Density functional theory, combined with numerical simulation of growth, indicates that this process involves rapid formation of low MW oligomers, followed by assembly of these species into low MW sheets. These can grow through further addition of low MW oligomers or by fusion into larger sheets. The mechanism of these growth processes leads to the prediction that even‐numbered sheets should be favored, and this surprising result is confirmed by ESI‐MS monitoring experiments of both activator growth and MAO aging.Methylaluminoxane (MAO) activators have sheet structures which form ion‐pairs on reaction of neutral donors such as octamethyltrisiloxane (OMTS). The ion‐pairs can be detected by electrospray ionization mass spectrometry (ESI‐MS) in polar media. The growth of these reactive precursors during hydrolysis of Me Modelling of kinetics using density functional theory, combined with numerical simulation, reveals that methylaluminoxane activators are sheets formed by assembly of linear oligomers, wherein the statistics and mechanism of aggregation favor formation of even‐numbered sheets. Hydrolytic methylaluminoxane (h‐MAO) is often used as an activator in single‐site polymerization catalysis. It serves multiple roles such as scavenging of impurities, alkylation of the catalyst precursor, and ionization to form active catalyst.3Al by a controlled hydrolysis.3Al present in all samples of h‐MAO can have deleterious effects on catalyst activity.Despite its useful properties, a large excess is required for high activity in solution3Al in dilute toluene suspension. The process is conducted isothermally below room temperature to provide a mixture of h‐MAO and unreacted Me3Al with very little gel formation.3Al, as in a suspension, which leads to cross‐linking, formation of insoluble aluminoxane as reported in the case of Et3Al,The commercial production of h‐MAO is achieved in a continuous process involving intimate mixing of water and a 3–5 fold excess of Me3Al has been studied in detail, both experimentally and also theoretically. At low temperatures and in a donor solvent , which moderates the hydrolysis reaction, the principle products formed are (Me2AlOAlMe2)n or (Me2AlOH)n (n≥2) depending on stoichiometry.2AlOAlMe2)n has never been obtained in pure form, is predominantly trimeric in solution, and is known to form h‐MAO+Me3Al when distillation is attempted.2AlOH)n is unstable at room temperature in donor solvents and is said to form MAO but with unusual characteristics such as 5‐coordinate Al, with residual OH groups.3Al that when the initial hydrolysis in non‐donor media is controlled, insoluble aluminoxane of this type can be converted to soluble aluminoxane through addition of an equimolar excess of Et3Al and also contains residual OH groups.The hydrolysis of Me3Al, furnished low MW oligomeric material, as might be expected for a classical, step‐growth condensation. Sinn invoked aggregation of these materials via dative Al−O interactions to form higher MW MAO as was hypothesized earlier.2Al(OAlMe)3OAlMe2) for the active component of MAO. We should note that Sinn and co‐workers adopted a different nomenclature based on the number of Al atoms (i. e. a Sinn pentamer) which we will use going forward.In non‐donor solvents, the preparation and composition of MAO has been studied at low temperature using both solvent fractionation, cryoscopy and NMR by the group of Sinn and co‐workers.3Al,3Al was required for effective catalyst activation using strained, t‐butylaluminoxane cages.n.2O2 rings are minimized. G2Al(OMTS)]+ [(MeAlO)n(Me3Al)mMe]− which can be detected and characterized by ESI‐MS.3Al in fluoroarene solvents.3Al with water and the composition of the mixture evolved on a longer time scale (tens of minutes to hours) to furnish a simpler mixture of ionic species. The final anion distribution was dominated by an anion with m/z 1375 with composition [(MeAlO)16(Me3Al)6Me]− – hereinafter −.MAO prepared by hydrolysis reacts with chelating donors such as OMTS to form ion‐pairs − the preferred pathway is [Me]− abstraction from Me3Al‐OMTS, while the most stable anions are derived from less stable, lower MW sheets such as 7,5 by the process of [Me2Al]+ abstraction. In practice it is difficult to distinguish between these ionization processesMost recently, we showed that there was very good agreement between ion intensities of these final mixtures as measured by ESI‐MS and what would be predicted based on both the stability and reactivity of likely neutral precursors, undergoing ionization by the most favourable process.3Al,3Al3Al is interpretable, based on anion vs. neutral stability.These theoretical and experimental results, especially those involving reaction of h‐MAO with R3Al‐OH2 formed reversibly from Me6Al2. The growth steps involve reaction of Me3Al‐OH2 with itself, Me3Al, or higher MW oligomers to form species with μ‐OH groups as summarized in Scheme Before we present our results, we would like to briefly review the work of Hall and co‐workersaE=9.2–50 kJ mol−1) consistent with experimental results. On the other hand, termination steps involve reaction of these same intermediates with Me3Al, and those steps possess even lower barriers (aE=2.1–3.5 kJ mol−1) dominated by the entropy loss in the transition state. Finally, two morphologies were identified for low MW oligomers; open ladder structures vs. “nido” cage precursors, ultimately leading to small and then larger cages. Though cage precursors were favoured thermodynamically over open, ladder structures by 9.2 kJ mol−1, the initial growth reactions leading to the cage precursors featured significantly higher activation energies (aE=58.5 vs. 25.1 kJ mol−1 for the rate determining steps). On this basis one would predict a kinetic preference for ladders of about 700,000 : 1 at 298 K as termination is much faster than growth, especially in the presence of a local excess of Me3Al.All of these growth steps feature fairly low activation energies  is in reasonable agreement with the experimental values for dissociation in gas phase (▵Ho=85.4 kJ mol−1 with ▵So=180.3 J mol−1 K−1).The first dissociation equilibrium has been studied in detail both experimentallyH≠ for exchange of terminal and bridging methyl groups in Me2Al6 is about 63–71 kJ mol−1 in hydrocarbon or toluene solution at −50 °C. A mechanism involving dissociation into monomeric Me3Al is widely accepted for this exchange process, though the solvent may play a role as the energetics differ significantly between hydrocarbon and toluene solution. Reanalysis of the original line shape dataH≠=72.8 kJ mol−1 with ▵S≠=107 J mol−1 K−1 for the rate‐determining, dissociation step. Since the temperature range of these experiments was only 10 °C, the entropy value is a rough estimate. However, on this basis one would expect ▵G≠=40.7 kJ mol−1 at 298 K in solution.However, it is known from experiment that ▵G=32.0 kJ mol−1 at 298 K, the free energy barrier to dimerization in solution (∼8.7 kJ mol−1) appears dominated by the loss of entropy in the transition state. From a practical perspective, it is widely appreciated that dimerization of Me3Al occurs at essentially diffusion controlled rates in solution at all temperatures (kd∼7.56×109 M−1 s−1 at 298 K).=[Me3Al]=0.055 M (i. e. [Me6Al2]=0.0275 M). Consumption of free water (green curve) is complete within 100 msec ‐ assuming homogeneous conditions, and efficient mixing. Consumption of Me6Al2 (dark red) occurs much faster; evidently, none of the monitoring experiments=0.04125 M), comparable amounts of (Me2AlOH)2 and Me5Al2OH are produced, though the latter predominates. Even at a 2 : 1 stoichiometry (Me2AlOH)2 and intermediates containing OH groups are still present, though soluble aluminoxanes, principally 1,2  are now dominant in the mixture. At this stoichiometry, there is a continuous excess of Me6Al2 over water, whereas the converse is true at lower Al : O ratios. At a 3 : 1 stoichiometry, most of the OH‐containing intermediates are consumed, though some residual (Me2AlOH)2 remains, while a mixture of 1,2, with 2,2 in lower amounts is formed. This feature is preserved at higher amounts of Me3Al, though little (Me2AlOH)2 would be formed at a 4 : 1 ratio.These conclusions are unaffected by the Al : O ratio within limits. For example, with a 50 mol% excess of Me2AlOH)n or Me5Al2OH are unstable at room temperature, and yet the simulation predicts that these compounds would dominate in the mixture at short time scales. With barriers to unimolecular CH4 elimination of at least 100 kJ mol−1, these compounds would have 12‐lives of nearly 10 h at 298 K and might even be isolable.It is generally known that compounds such as  and [tBu2AlOAltBu2]2 n with n=6, 9 and 12. On the other hand, hydrolysis of tBu3Al using a hydrated salt followed by thermolysis affords a mixture of compounds of which II and (tBuAlO)8 (III) predominate suggesting a different fate when I (or tBu2AlOH) is generated in the presence of tBu3Al. On the theoretical front species such as (Me2AlOH)n (n=3 or 4) are also considered plausible precursors for formation of much more stable nanotubes,This is certainly the case for direct hydrolysis of oth tBuAlOH3 (I)2AlOH)2 or Me5Al2OH with Me6Al2 thinking their direct association might be competitive with steps involving monomeric Me3Al, for which no barrier is predicted but the equilibrium concentration of monomer is very low relative to Me6Al2. These reactions are facile with barriers in the range 50–60 kJ mol−1 for the dinuclear Al‐OH species (n+m=2) shown in Scheme 6Al2 is used up rapidly under stoichiometric condition, while both (Me2AlOH)n or Me5Al2OH are much more reactive towards monomeric Me3Al when excess Me6Al2 is present.We examined the binding of MeAlOH2 or 2AlOH)2 or Me5Al2OH. For example, either might react with excess Me6Al2 to furnish in the case of Me5Al2OH, either 1,2+Me3Al  and methane. We calculated barriers of 110.8 and 113.3 kJ mol−1 for this initial reaction, involving Me5Al2OH and (Me2AlOH)2, respectively. The only process studied that is even roughly competitive is the reaction of (Me2AlOH)2 with itself, producing the species IV shown in Scheme −1. This species can undergo intramolecular CH4 elimination to form 2,0,2 but with a more significant barrier of 87.1 kJ mol−1.We have examined other possible reaction pathways of  might form (MeAlO)8 with a structure analogous to that proposed for (tBuAlO)8.−1) is significantly lower in energy than that for forming the nido form (101.9 kJ mol−1) it is possible for the ladder form to isomerize to the more stable nido form (ΔΔG=−9.3 kJ mol−1) via ring opening and this barrier is surprisingly low (64.1 kJ mol−1). Thus, cage precursors can still be generated in this manner. We note that formation of a 4,0 cube from the nido 2,0,2 structure is kinetically quite unfavourable (ΔG≠=143 kJ mol−1) so absent reaction with Me3Al, further hydrolysis, or self‐condensation this compound would persist in solution.Note that 2AlOH)2 with Me5Al2OH, or condensation of Me5Al2OH with itself are also feasible. In these two cases, the products are expected to form 2,1,1 and i‐2,2 via subsequent intramolecular elimination of CH4 2 acts as a proton source , while the other scenario , involves barriers of 72.5 and 102.9 kJ mol−1. Since the first step for the latter process is much lower in energy than the alternative, while the second step is over 100 kJ mol−1 it is clear that the intermediate formed  would dominate and persist in solution. Formation of i‐2,2 from Me5Al2OH involves barriers of 80.5 and 86.2 kJ mol−1 while this aluminoxane is 41.1 kJ mol−1 higher in energy than 2,2 and would isomerize readily.Reaction of 2. At a 3 : 1 stoichiometry we return to the same conditions as in Figure 1,2 with lesser amounts of 2,2 and very little 4,2 .We incorporated these reactions into the model and the results are depicted in Figure IV (X=Y=OH) is an A3B3 type of monomer2 groups are the reactive groups present with respect to further methane elimination. The usual result of a step‐growth reaction involving an A3B3 monomer is an insoluble, network polymer. This may be related to the formation of insoluble, aluminoxane gels that are always generated during hydrolyses of either Me3Al (or Et3Al) under near stoichiometric conditions. We suspect the other multi‐functional intermediates such as 2,0,2 or i‐1,1,2 are also capable of gelation, either on their own, or certainly through reaction with other multi‐functional intermediates. Conversely, Me3Al‐rich species such as 1,2  might serve as a source of Me3Al leading to aluminoxane gel depleted in OH groups.Note that structure 3Al . In our monitoring studies we never detected anionic species with OH groups, though these form during adventitious hydrolysis of commercial MAO solutions so we can't exclude their formation. Certainly, OH groups are vanishingly small in commercial MAO by other spectroscopic methods.Not much is known about aluminoxane gel other than it does contain residual OH groups and can be dissolved upon addition of sufficient Me3Al over dissolved water, and these conditions (e. g. slow or controlled addition of water to Me3Al) reflect how MAO is prepared both in the laboratory and under industrial conditions. The initial product distribution is characterized by low MW oligomers – see Figure In essence, to produce high yields of soluble aluminoxane, one must be working with a significant excess of Me16,6 is certainly driven by thermodynamics− (m/z=463) derived from 4,3 or 4,4 was seen in these monitoring experiments.4,3 is also accessible in fewer steps through dimerization of 2,3, forming 4,5+Me3Al. Indeed, when this process is included, one would predict that sheet 4,3 would be the major aggregation product formed from a mixture of 1,3 and 2,4 formed via hydrolysis.An anion − or − via direct reaction, accompanied by loss of Me6Al2.Another feature of the experimental growth reaction is that under certain conditions, low MW anion precursors are transforming directly to higher MW precursors without the detectable intervention of intermediates. These observations suggest it might also be possible for larger sheets to fuse together at some point in the growth process, thus by‐passing intermediates that can only form in a step‐wise manner involving low MW oligomers like 12,7 which differ in energy by 3.4 kJ mol−1. The more stable 5‐C sheet might have formed by fusing the Sinn tetramer (or a saturated version thereof) with saturated versions of 4,3 and 5,3  but we have not investigated these reactions as we are uncertain as to which combinations give rise to which larger sheets.This concept finds some support in the structures of the larger 5‐C sheets23, 2416,6. To model this complex process, we made several simplifying assumptions, based on the theory just presented.We have suggested that there are at least three growth phases ‐ assembly of small sheets from linear precursors, possible fusion of small sheets into larger ones, all of which at a certain size range become detectable by ESI‐MS, and a slower growth phase, related to aging, that leads to maturation of the larger sheets which have a local minimum in stability with 3Al where the stable forms 1,3 and 2,4 located by theory are favoured at equilibrium. We used a simplified set of reactions to represent this process rather than the detailed simulation discussed earlier.First, water is consumed through rapid formation of the Sinn dimer and trimer, stabilized by binding of Me−1 min−1 as this roughly corresponds to the overall rate constant for this multi‐step process. Similarly, binding of Me3Al to the products was simplified to one step with a rate constant of 8800 M−1 min−1. In both cases binding is very favourable (see earlier discussion) and was rendered irreversible for convenience. This makes no difference to the simulation results within limits.The two hydrolysis steps were rate determining with a rate constant set to 1200 MSecond, these linear oligomers associate to form more stable aluminoxanes as was demonstrated in Figure −1 min−1. This may seem artificial but in the actual simulation  the 4,m sheets were always favoured upon completion, and even during the initial kinetic stages.Here is where we introduced a kinetic bias between odd‐ vs. even‐numbered species, where the fastest process (the third) proceeded 4 times more quickly than the slowest (the first). The fastest process had a rate constant of 8800 M3,4 and 4,4 to combine so as to produce a mixture of 6,4, 7,4 and 8,4 (+ 2 Me6Al2) at identical rates (k=2200 M−1 min−1). Then, these intermediate sheets were combined to produce 12,6‐16,6 (+ Me6Al2) as suggested earlier but at 2‐fold lower rates (k=1100 M−1 min−1) compared with the slowest initial aggregation steps. This is largely based on the intuitive expectation that more steps are required for these fusion processes, and also by comparison of simulated to the experimental data, particularly the increase in average m/z ratio with time .We then allowed 1,2 or 2,3 at the slowest rates (k=250 or 500 M−1 min−1). We retained a kinetic bias between reactions involving 1,2 (slowest) vs. 2,3 (faster). In order to reproduce the basic features seen we also required that conversion of 16,6 to higher MW sheets was 20× slower than conversion of lower MW sheets to 16,6. This is consistent with a sheet of this size being a local minimum in stability.Finally, we invoked “aging” of the mixture through reaction of these product sheets with 7,4]− is the most stable anion per aluminoxane repeat unit) to weight the solution concentrations resulting from simulation. Full details are provided as Supporting Information.The final part of the simulation deals with solution concentrations vs. anion intensities. In order to model the latter, we used the results of theory discussed in Ref. [24] , heightened amounts of − are present using larger Al : O ratios and the reaction to form − is actually slower at higher Al : O ratios. The finding that even‐numbered anions are favoured over odd‐numbered ones upon completion of the growth reaction is related to the initial assumptions about the reactivity of 2,3 vs. 1,2 as outlined in Scheme 16,6), it is likely a more sophisticated simulation would capture the observed phenomena more accurately.It is interesting to note that we are able to reproduce some of the experimental features of the growth reaction where the relative intensity of the low MW anions 6,− to 8,46,4− to [3Al under controlled conditions will produce a mixture of low MW, mainly linear aluminoxane precursors. These can aggregate into sheets, where the latter can grow either via the aging process involving addition of a low MW oligomer, or by mutual reaction along reactive edges. Cessation of growth by this process favors the formation of even‐numbered sheets as is observed experimentally.Density functional theory, combined with numerical simulation provides a framework for the interpretation of the oligomerization reactions studied by ESI‐MS. Namely that hydrolysis of excess MeAs both theory and experiment concur that sheet structures are the reactive components in the size range of MAO suggested by experiment, it is of interest as to how for example metallocene catalyst activation occurs by MAO. We view the details of this process as still an open question, especially considering that the theoretical models for MAO employed to study this in the past were cages.19, 21Normalized ESI‐MS intensity data  are included as Supporting Information . Anion intensities were calculated using anion stability data reported in ref. 24 in PhF solvent using the Boltzmann distribution. These values were then used to weight the solution concentrations obtained by numerical simulation of the growth reaction using the COPASI software.T=298 K and p=1 atm.Density functional theory calculations were carried out by Gaussian 16 software,The authors declare no conflict of interest.As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re‐organized for online delivery, but are not copy‐edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors.Supporting InformationClick here for additional data file.


Density functional theory calculations demonstrate that the Co SAC aggregates can interact with the sulfur species in a synergistic manner that enhances the electrocatalytic effect and promote the performance of sulfur cathodes. For example, Li–S cells prepared from the Co SAC aggregates exhibit outstanding capacity retention  and excellent rate capability . An ultrahigh area specific capacity of 12.52 mA h cm−2 is achieved at a high sulfur loading of 11.8 mg cm–2.Electrocatalysis is critical to the performance displayed by sulfur cathodes. However, the constituent electrocatalysts and the sulfur reactants have vastly different molecular sizes, which ultimately restrict electrocatalysis efficiency and hamper device performance. Herein, the authors report that aggregates of cobalt single‐atom catalysts (SACs) attached to graphene via porphyrins can overcome the challenges associated with the catalyst/reactant size mismatch. Atomic‐resolution transmission electron microscopy and X‐ray absorption spectroscopy measurements show that the Co atoms present in the SAC aggregates exist  Aggregates of Co single‐atom catalysts (SACs) on graphene are synthesized from a Co(II) porphyrin complex and graphene oxide. The Co atoms in the aggregates exist with spatially‐resolved dimensions that are commensurate with the sulfur species found in sulfur cathodes. As a result, the Co SAC aggregates synergistically interact with the sulfur species and thus maximize electrocatalytic effect in sulfur cathodes. The synthesis of graphene‐based SACs typically consists of three steps: mixing a suspension of graphene oxide (GO) with an aqueous solution of an inorganic metal salt, freeze‐drying the combined suspension, and then thermally annealing the obtained composite under the reducing atmosphere of ammonia. In the last step, ammonia provides a means to simultaneously dope the graphene with beneficial heteroatoms  while complexing the single‐atom metals. Such processes are often challenged by the use of a toxic gas as the heteroatom source and the tendency of the metal atoms to form clusters or even larger particles during the annealing step. The difficulty can be expected to be managed through molecular design as the unique surface of graphene provides opportunities to form π‐stacking interactions with conjugated molecules such as pyrene, perylene bisimide, polythiophene, and, notably, porphyrins. Such noncovalent approaches are attractive when compared to their covalent counterparts as the former do not affect the π‐conjugated structures of graphene and can even mitigate the structural defects that are often found on the basal planes of graphene. Indeed, graphene‐based composites that are prepared via noncovalent interactions have been employed in a number of applications, including sensing, photothermal systems, lithium‐ion batteries, OER chemistry, and the oxygen reduction reaction.Graphene holds great promise for constructing high‐performance functional materials because of its extraordinary physical and chemical properties, such as a conjugated electronic structure, an ultra large specific surface area, and tunable surface chemistry.1 Sing–1) as well as the high abundance and environmental friendliness of sulfur. However, their commercial applications are severely restricted by two critical factors: 1) a loss in the active material sulfur during iterative charge/discharge cycles due to the “shuttle effect” of the polysulfides and 2) sluggish cathode kinetics. Considerable efforts have been employed to overcome these limitations, typically by utilizing electrocatalysts to promote the chemical reactions in sulfur cathodes. So far, a variety of nanostructured materials, including nanoparticles , nanotubes (MoS2), nanorods , nanosheets , nanocubes (Ni3N0.85), nanoribbons (VN), and nanoclusters (Nb2O5–x) have been incorporated into carbon materials and used as electrocatalysts in sulfur hosts. Since only the exposed surfaces and edges of these electrocatalysts are active, the sulfur host materials typically require a relatively high catalyst loading (often >20 wt%) or even pure catalyst matrices to achieve satisfactory effects. By contrast, SACs can be expected to exhibit a 100% atomic utilization efficiency and a number of SACs have been demonstrated to promote the cathode reactions in Li–S batteries. However, current SACs typically do not deliver optimal catalytic activities in sulfur cathodes because of a range of intrinsic challenges, including a propensity of the SACs to coalesce during preparation and the size mismatch between the SACs and the relatively large reactants, such as S8 and polysulfides, which restricts interaction between the two components. Matching the distances between the metal atoms in the SACs with the molecular sizes of the sulfur species found in sulfur cathodes, while suppressing the detrimental coalescence of the single‐atom metals, can be expected to enhance the electrocatalytic effects and afford Li–S batteries that exhibit superlative performance metrics.Lithium–sulfur (Li–S) batteries are often regarded as next‐generation energy storage devices because of their high energy density (2600 W h kgf sulfur.12 How4) was preserved and effectively prevented the formation of Co—Co bonds in the aggregates. As a result, the aggregates of the Co SACs promoted the catalytic activity of the Co atoms by enabling synergistic interactions with polysulfides. When used as an electrocatalytic sulfur host, the Co‐NG(800) significantly enhanced the performance of Li–S batteries in terms of specific capacity and rate capacity  as well as a cycling stability (505 mA h g−1 after 600 cycles at 0.5 C). Ultrahigh area specific capacities were also measured from cells with high sulfur loadings . In addition to establishing a new approach to solving the longstanding challenges associated with Li–S batteries and to realizing high‐performance devices, the strategy described offers a general guide for adapting SACs for use in a broad range of contemporary applications.Herein, we report aggregates of Co SACs that feature commensurate size with the sulfur reactants found in sulfur cathodes and show that these catalysts significantly enhance the electrocatalytic effects required by sulfur cathode chemistry. The key material, designated as Co‐NG(800), was obtained by combining a Co(II) porphyrin complex with GO followed by hydrothermal treatment and thermal annealing. A series of high‐angle annular dark field‐scanning transmission electron microscopy (HAADF‐STEM) and X‐ray absorption spectroscopy (XAS) measurements in conjunction with density functional theory (DFT) calculations revealed that the intrinsic coordination structure of the Co(II) porphyrin complex porphyrin tetraiodide ([CoTMPyP]I4), a water‐soluble Co(II) porphyrin complex. First, an aqueous solution of [CoTMPyP]I4 was mixed with an aqueous suspension of GO. A series of spectroscopic and Zeta potential measurements revealed that the porphyrins were attached to the GO sheets via π‐stacking interaction and electrostatic attraction  was hydrothermally treated at 180 °C and then thermally annealed at 400 or 800 °C to convert GO into graphene, which was simultaneously doped with heteroatom N and loaded with Co atoms during the processes. The products were designated as Co‐NG(400) and Co‐NG(800), depending on the annealing temperature. As will be shown below, the use of the higher annealing temperature facilitated transformation of the Co SACs to an aggregated form that differed from those found in metal clusters or nanoparticles  was used, and a graphene (designated as G) that was obtained by repeating the synthesis in the absence of a porphyrin additive.As summarized in s Figure . The res8 and various polysulfides  are common reactants found in the cathodes of Li–S batteries. These species are larger than those found in the HER, OER, O2, and CO2 reduction reactions . Size matching is a key criterion in SACs as size differentials between the catalysts and the reactants can hamper efficiency, even if the isolated metal atoms are fully exposed. A potential solution to this issue is shown in Figure Macrocyclic S2.2Figure Alternatively, the Co SACs may be incorporated into the graphene plane via chemical reactions between the Co porphyrin complex and the GO starting material as GO is known to feature myriad structural defects and functional groups.The Co‐NG(800), NG, and G were further investigated using X‐ray photoelectron spectroscopy (XPS). The Co content of Co‐NG(800) was determined to be 2.50 wt%. The N content values measured for Co‐NG(800) and NG were relatively high , particularly when compared to G (2.23 wt%), due to the porphyrin additive used during the synthesis. Deconvolution of the XPS data indicated that pyridinic‐, pyrrolic‐, and graphitic‐type N atoms were present, and that the pyridinic N atoms were dominate. Moreover, the pyridinic N atoms appeared to be complexed to Co as the corresponding binding energy recorded for Co‐NG(800) was found to be 0.3 eV higher than that recorded for NG or G.K‐edge X‐ray absorption near‐edge structure (XANES) spectrum recorded for Co‐NG(800) contained a weak pre‐edge feature at 7709 eV, which was assigned to a 1s → 3d transition, as well as a shoulder peak and well‐resolved double absorption‐edge peaks at 7715.2, 7726.9, and 7734.5 eV, which corresponded to 1s → 4p transitions. The weak pre‐edge absorption indicated that the Co atoms adopted a centrosymmetric coordination structure. In addition, the absorption edge recorded for Co‐NG(800) was located in‐between those recorded for a Co foil (Co0) and Co3O4 , and thus enabled the oxidation state of the complexed Co atoms in Co‐NG(800) to be ascertained.The chemical environment of the Co atoms in Co‐NG(800) was further investigated using XAS. As shown in Figure nsitions.25 TheR space, as obtained from the k3‐weighted extended X‐ray absorption fine structure (EXAFS) data, for Co‐NG(800), Co3O4, and a Co foil. In contrast to the peaks observed at 1.50 and 2.42 Å, which stemmed from the Co—O and Co—Co bonds in Co3O4, and the peak at 2.18 Å, which was assigned to the Co—Co bonds in the Co foil, the dominate peak at 1.41 Å in the spectrum recorded for the Co‐NG(800) was attributed to the presence of Co—N bonds. Fitting the EXAFS spectra enabled a coordination number of four  to be assigned to the Co atoms in Co‐NG(800)  was attributed to Co—N contributions  may form via thermally facilitated processes. To test this hypothesis, the CoTMPyP‐GO composite was annealed at a lower temperature (400 °C) and the corresponding product was designated as Co‐NG(400). The Co content of Co‐NG(400) was measured by XPS to be 2.55 wt%. HAADF‐STEM confirmed that the Co atoms in the Co‐NG(400) adopted an isolated form and the Co K‐edge XAS data indicated that the Co atoms retained the Co–N4 coordination structure  atoms while forming stabilizing interactions with the underlying graphene substrate. Phthalocyanines, salens, bipyridines, and other heteroaromatics with structures and functions that are similar to those of the porphyrins can be expected to serve as potential alternative organic ligands.Since single atoms have high surface free energy, they are thermodynamically unstable and prone to form clusters or nanoparticles, particularly at elevated temperatures.27 Lik2.3m) in a mixture of 1,3‐dioxolane (DOL) and 1,2‐dimethoxyethane (DME) (1:1 v/v) containing LiNO3 (2 wt%) as electrolyte. Preliminary tests demonstrated that the Li–S cells prepared from S@Co‐NG(800) afforded higher performance metrics than the cells prepared from S@Co‐NG(400) , S@Co‐NG(400), S@NG, and S@G, respectively. The sulfur loading was confirmed by the significant decreases in the specific surface areas and pore values measured for the host materials  and then to insoluble Li2S2 and Li2S. In the following anodic scan, the dominate oxidation peak was attributed to the conversion of Li2S to S8. The conversion of S8 to lithium polysulfides at the S@Co‐NG(800) cathode  occurred at more positive potential when compared to the cathodes containing S@NG or S@G . Similarly, oxidation of the Li2S at the S@Co‐NG(800) cathode  took place at more negative potential than that recorded for the S@NG and S@G cathodes . Moreover, the S@Co‐NG(800) cathode exhibited the greatest redox peak currents among the three cathodes tested. Galvanostatic charge/discharge profiles were also recorded at a current rate of 0.1 C (1 C = 1675 mA g–1). As shown in Figure –1 vs 1257 or 1171 mA h g–1, respectively). Collectively, these data indicated that the Co SACs embedded in the S@Co‐NG(800) were capable of promoting the cathode reaction kinetics.–1 vs 301 and 190 mA h g–1, respectively). When the current rate was re‐set back to 1 C, a specific capacity of 864 mA h g–1 was measured for the S@Co‐NG(800) cathode. The value was comparable to the initial value of 877 mA h g–1, indicating good reversibility of the S@Co‐NG(800) cathode. Indeed, after 50 subsequent cycles, a specific capacity of 838 mA h g–1 was measured, corresponding to a capacity retention of 97%. The excellent rate capability and capacity retention of the S@Co‐NG(800) cathode were attributed to the embedded Co SACs that promote the cathode reactions of Li–S cells. Figure E) between the charge and discharge plateau was correlated with the polarization of the cathode. In contrast to the galvanostatic profiles acquired for the S@NG and S@G cathodes . The smaller polarization recorded for the S@Co‐NG(800) cathode reflected faster reaction kinetics and was attributed the electrocatalytic effects provided by the Co SACs.The rate capabilities of the cells were evaluated by increasing the current rate from 0.2 C to 6 C Figure . Of the  cathode.22d In–1 and retained a value of 505 mA h g–1 after 600 cycles, corresponding to a capacity decay of only 0.08% per cycle. For comparison, the capacity decays were measured to be 0.21% and 0.24% per cycle for the S@NG and S@G cathodes, respectively, after 200 charge/discharge cycles. Additionally, the S@Co‐NG(800) cathode also exhibited a constant Coulombic efficiency that was close to 100% over the long‐term cycling study, which is in sharp contrast to the significant decreases observed for the S@NG and S@G cathodes.The long‐term cycling stabilities of the Li–S cells were measured at 0.5 C since the shuttle effect of polysulfides is pronounced at low current rates Figure . The S@C–2, the corresponding Li–S cells exhibited ultrahigh area specific capacities of 6.20, 9.37, or 12.52 mA h cm–2 at 0.05 C, respectively. The values are significantly higher than the threshold required for commercial lithium‐ion batteries (4 mA h cm–2). Cycling stability tests were further performed at 0.1 C and the data showed that the Li–S batteries prepared with gradually increased sulfur loadings worked well along with Coulombic efficiencies that were close to 100%. In particular, the Li–S cell prepared at a sulfur loading of 11.8 mg cm–2 displayed an area specific capacity of 10.47 mA h cm–2 initially and 8.86 mA h cm–2 after 75 cycles at 0.1 C, corresponding to a capacity retention of 85%. The area sulfur loading and area specific capacity values described are higher than the values reported for the Li–S batteries that contained SACs , Li–S cells were prepared with cathodes that contained relatively high sulfur loadings. As summarized in Figure  h cm–2).29 Cyc2.4Figure–1 for electrodes containing Co‐NG(800), NG, or G. As opposed to a featureless CV curve that was recorded from a blank electrolyte , the two reduction peaks detected at ≈ –1.08 and –1.41 V in the cathodic scan (labeled as A and B) were ascribed to the conversion of S8 to polysulfides and then to Li2S, respectively. In the anodic scan, two oxidation peaks were detected at –1.24 and –1.04 V (labeled as C and D) and were attributed to the reverse reactions . The intensities of the peak currents of the redox events followed the order: Co‐NG(800) > NG > G. This finding indicated that the SACs present in the Co‐NG(800) facilitated the conversions of sulfur at the corresponding electrode. Furthermore, as shown in Figure The electrocatalytic properties of Co‐NG(800) were further investigated using a three‐electrode system . –1. As shown in Figure DLi+) values using the Randles–Sevcik equation , A is the area of the electrode, CLi+ is the concentration of Li ions in the electrolyte, and ν is the scan rate.To gain a deeper understanding of the underlying reaction kinetics, CV curves were collected at a series of scan rates that ranged from 1 to 49 mV sDLi+ values since they maintained their shapes as the scan rate was increased. As shown in Figure Ip increased linearly as a function of the square root of scan rate (v1/2) in both oxidation and reduction processes (reflective of a mass transport limited process), from which the DLi+ values were derived. During oxidation, the DLi+ value measured for the Co‐NG(800) electrode  was 1.4 and 6.1 times higher than the values measured for the NG and G electrodes . Similarly, for the reduction reaction, the DLi+ value measured for the Co‐NG(800) electrode  was 1.6 and 5.6 times higher than those measured for the other electrodes . Notably, the Co‐NG(800) electrode  exhibited faster reaction kinetics when compared with the Co‐NG(400) electrode   electrode were measured to be 2.1 and 2.2 times higher than the values measured for the Co‐NG(400) electrode , NG, or G . As shown in Figure2S8, the nucleation and growth of Li2S, and the reduction of Li2S6, respectively. As expected, the capacity corresponding to the Li2S precipitation recorded for the Co‐NG(800) cathode  was significantly higher than those recorded for the NG and G cathodes . This result indicated that the Co SAC aggregates substantially promoted the conversion of Li2S. Aggregates of the Co SACs were also found to promote Li2S precipitation more readily than their isolated form, as the corresponding specific capacity recorded for the former (103.6 mA h g–1) was 1.5 times higher than that recorded for the latter  and S@NG composites. The difference was attributed to the formation of new interactions, presumably between the sulfur and the N heteroatoms and/or the Co SACs, that facilitate the cathode reactions of Li–S batteries. Significantly, the new absorption peak recorded for S@Co‐NG(800) was stronger than that recorded for S@NG, indicating that the Co SACs provide stronger interactions and thus may play a dominate role in promoting the sulfur cathode reactions.To unveil the electrocatalytic mechanism of the Co‐NG(800), XANES spectroscopy was used to analyze the interactions formed between Co‐NG(800) and the sulfur species present during the charge/discharge processes. K‐edge XANES spectra were collected from the cathode materials retrieved at different charge/discharge states . These results indicated that the structure of the single‐atom Co aggregates was essentially unchanged during the charge/discharge cycle and that interactions formed between the Co SACs and the sulfur species persisted throughout the electrochemical process.Co  As shown in Figure 4). After geometry optimization, the distances between the adjacent Co atoms were determined to be 0.32, 0.40, and 1.37 nm, consistent with experimental values  is beyond the size of a Li2S6 molecule and thus the absorption can occur only through one Co atom. By contrast, in the Co‐NG‐0.40 and Co‐NG‐0.32 models, a Li2S6 molecule can be simultaneously absorbed by two Co atoms because the distances of the adjacent Co atoms  are commensurate with the size of a Li2S6 molecule. Therefore, the bidentate nature of such absorption can be expected to enhance the binding with a Li2S6 molecule. The adsorption of other sulfur species was found to be similar to the manners described for Li2S6 on the different substrates  values calculated for each model, which follow the order: Co‐NG‐0.32 > Co‐NG‐0.40 > Co‐NG‐1.37. These results indicate that the aggregates of Co SACs exhibit stronger absorption characteristics with various sulfur species than their isolated forms.G) values calculated for the reactions on the different substrates. The ΔG values calculated for the conversion of Li2S2 to Li2S is the least negative, indicating that the reaction is the rate‐limiting step. The ΔG values calculated for this step using the Co‐NG‐0.32 and Co‐NG‐0.40 models are more negative than those calculated with the Co‐NG‐1.37 model or an isolated state. This result is consistent with the experimental data which showed that the single‐atom Co aggregates facilitate the conversion of Li2S2 to Li2S more efficiently than their isolated form. Furthermore, the ΔG values for each step were found to change in the following order: Co‐NG‐0.32 > Co‐NG‐0.40 > Co‐NG‐1.37 > isolated state, suggesting that the single‐atom Co aggregates promote the entire discharge process more markedly than their isolated form. Collectively, these results explain why the Li–S cells prepared using the Co‐NG(800) material as a sulfur host exhibit better performance in terms of specific capacity, rate capability, and cycling stability when compared with the analogous cells that were prepared from the Co‐NG(400) material.Figure ing step.22 The32S precipitation tests revealed that electrodes containing the Co SAC aggregates exhibited faster Li+ diffusion coefficients and an increased Li2S precipitation when compared to control electrodes that contained the Co SACs existing in an isolated form. The Li‒S cells prepared using Co‐NG(800) as a sulfur host also showed outstanding performance metrics, including a high specific capacity (1346 mA h g‒1 at 0.1 C), a high rate capacity (648 mA h g‒1 at 6 C), and excellent cycling stability . Moreover, an ultrahigh area capacity of 12.52 mA h cm−2 was measured from a Li–S cell with a high sulfur loading of 11.8 mg cm−2. Collectively, these results provide new insights into the electrocatalytic processes in the sulfur cathodes of Li‒S cells, and the methodology described offers a general strategy for adapting other SACs for use in contemporary electrocatalytic reactions.In summary, aggregates of Co SACs on graphene were synthesized from readily available reagents, including a Co(II) porphyrin complex and GO. The Co atoms on the graphene sheets can migrate and aggregate when heated yet, due to the intrinsic coordination environment of the metals, are prevented from forming Co—Co bonds in the aggregates. DFT calculations revealed that the Co atoms can form synergistic interactions with relatively large reactant sulfur species and, as a result, maximize electrocatalytic effects. A series of three‐electrode measurements and Li4The details of the methods are provided in the Supporting Information.The authors declare no conflict of interest.Supporting InformationClick here for additional data file.


The methylation of lysine residues has been involved in the multiple biological and diseases processes. Recently, some particular non‐histone proteins have been elucidated to be methylated by SMYD2, a SET and MYND domain protein with lysine methyltransferase activity.SMYD2 was evaluated in synovial tissue and cells derived from rheumatoid arthritis patients. We confirmed TRAF2 could be methylated by SMYD2 using Mass spectrometry, pull‐down, immunoprecipitation, methyltransferase assay, ubiquitination assay, luciferase reporter assays, and western blot analyses. Using loss‐ and gain‐of function studies, we explored the biological functions of SMYD2 in vitro and in vivo. Using acute and chronic inflammation with different mice models to determine the impact of SMYD2.Here, we first time confirmed that the cytoplasmic protein TRAF2 as the kernel node for NF‐κB signaling pathway could be methylated by SMYD2. SMYD2‐mediated TRAF2 methylation contributed to the durative sensitization of NF‐κB signaling transduction through restraining its own proteolysis and enhancing the activity. In addition, we found knocking down of SMYD2 has different degrees of mitigation in acute and chronic inflammation mice models. Furthermore, as the lysine‐specific demethylase, LSD1 could resist methylation on TRAF2 induced by SMYD2.Our data uncovered an unprecedented cytoplasmic protein network that employed methylation of TRAF2 for the maintenance of NF‐κB activation during inflammatory diseases. We confirmed that the cytoplasmic protein TRAF2 as the kernel node for the activation of the NF‐κB signaling pathway could be methylated by SMYD2 in various inflammatory diseases, and methylation of TRAF2 by SMYD2 contributed to the durative sensitization of NF‐κB signaling transduction through restraining its proteolysis and enhancing the activity. NF‐κB plays the pivotal role in the survival, activation and differentiation of various innate immune cells that potentially functions the first line of defense against the foreign invasion.SMYD2 is increased in synovial tissue and cells derived from rheumatoid arthritis patients.The cytoplasmic protein TRAF2 can be methylated by SMYD2 in various inflammatory diseases.TRAF2 methylation contributes to the durative sensitization of NF‐κB signaling transduction.Knocking down of SMYD2 has different degrees of mitigation in acute and chronic inflammation mice models.TRAF family includes seven members in mammalian cells and has been reported to engage in innate and adaptive immunity. All TRAFs share a universal RING domain that potentially functions as E3 ubiquitin ligase.Here, we reveal that TRAF2 is the crucial positive factor for the activation of NF‐κB signaling in inflammation and the methylation of TRAF2 induced by SMYD2 could aggravate the inflammatory response. The methylation of TRAF2 avoids degradation by ubiquitin‐proteasome proteolytic, thus stabilizing TRAF2, which contributes to the prolonged NF‐κB signaling transduction in inflammatory diseases. Meanwhile, the first identified demethylase LSD1 has the capacity of reversing the methylation of TRAF2.22.1Although a part of biologic functions for SMYD2 has been clarified, the roles of SMYD2 in non‐neoplastic cellular biology and diseases like inflammation remain largely unclear. We examined SMYD2 expression in clinical synovium samples collected from RA and osteoarthritis (OA) patients and healthy donators. We found a significant increase of SMYD2 expression in RA compared with healthy or OA tissues Figure  and B. T2.2Tnfaip3), is a deubiquitinase enzyme with a crucial function in the inhibition of various proinflammatory molecules, including RIPK1 and IKKγ. It has been demonstrated that Ash1L, an H3K4 methyltransferase, could enhance A20 expression through induction of H3K4 modification at the Tnfaip3 promoter.SMYD2, the results revealed that silence of SMYD2 led to the reduced A20 mRNA expression in TNF‐α stimulated cells  was used to identify interacting partners in 293T cells. We found a distinct band at ∼55 kDa only in Myc‐SMYD2 samples Figure . Each lay Figure . These r2.5Since SMYD2 could interplay with TRAF2, considering its methytransferase function, we next asked whether SMYD2 could methylate TRAF2. The SMYD2 knockout 293T cells were transfected with TRAF2, and stimulated with TNF‐α. The extent of lysine methylation of TRAF2 was greatly increased by cotransfection with SMYD2 and was significantly declined in SMYD2 knockout cells Figure . In vitr2.6SMYD2, the K63 modification on RIPK1 was decreased accordingly  was less than the WT mice, but the immature B cells (CD19+ IgM+ IgD−) showed no difference in both groups. Next, we purified the pan B cells from mice spleen and evaluated the survival capability without any stimulation. As Figure Smyd2+/− mice compared with WT mice  is the first enzyme identified to remove the methyl group from methylated lysines on histone proteins.2.10Smyd2+/‐ mice to evaluate the roles of SMYD2 on colitis, collagen‐induced arthritis (CIA) and imiquimod induced psoriasis. Initially, western blot determined that SMYD2 levels remained low in main organs and macrophages of Smyd2+/‐ mice compared to the WT mice   Figure . Furthers Figure . It has s Figure  and E.Smyd2fl/fl and Smyd2fl/flCD19‐Cre mice with acute colitis induced by DSS. As shown in Figure Smyd2fl/flCD19‐Cre mice were pronouncedly longer. H&E staining demonstrated that the administration of DSS leaded to colonic ulceration associated with a larger range of epithelial crypt loss and more inflammatory cell infiltration into the mucosa in the Smyd2fl/fl mice. We observed a marked decrease in the expression of CD19 in the spleen from Smyd2fl/flCD19‐Cre mice, further substantiating the finding  induced phosphorylation.et al showed that the phosphorylation of TRAF2 by PKC mediated its K63‐linked polyubiquitination.SMYD2 belongs to the Smyd family and is known for its methylation of H3 at lysine 4 or lysine 36 as the methyltransferase with the results of specific genes transcription. Recently, much more information about its methylation of the nonhistone proteins was uncovered and which implies multiple functions of SMYD2 in physical or pathological conditions.Smyd2 heterozygous mice owed much less matured B cells in the spleen, and the survival of B cells was also shorter compared with the wild type mice. In a word, the modulation effects of TRAF2 on NF‐κB activations are much more complicated and elaborate.As the hinge point of the canonical and noncanonical signaling pathway, TRAF2 together with TRAF3, BIRC2 and BIRC3 could suppress the noncanonical NF‐κB signaling pathway in resting cells by targeting NIK for degradation.As the first identified histone demethylase LSD1 has proved to demethylate the non‐histone proteins methylated by SMYD2. For example, the tumor suppressor p53 could interact with LSD1 and be demethylated on K370me induced by SMYD2.4Our results show that the overexpression of SMYD2 could promote both the canonical and non‐canonical NF‐κB pathway in the inflammation diseases. And firstly, we point out that TRAF2 could interact with SMYD2 and be methylated by SMYD2, so as to promote the NF‐κB activation, and which could be antagonized by LSD1 specifically. Our data provide the novel clues for the treatment of inflammation diseases.5Detailed methods can be found in the Supplementary materials 1.5.1Smyd2+/‐ heterozygous mice and Smyd2fl/fl mice were obtained from Institute of Model Animal, Wuhan University. They were crossed with Cd19‐Cre mice to generate Smyd2fl/flCd19‐Cre mice. Control mice for all experiments in this study were littermate Smyd2fl/fl mice lacking the Cre transgene. Mice were housed in individually cages fed a standard diet with freely available food and water. All the mouse strains were used at an age range of 8–10 weeks.All the animal operation was complied with the guiding principles of laboratory animal care formulated by Fudan University. Eight‐week‐old male C57bl/6J mice were purchased from SLAC Laboratory Animal Co.,Ltd, Shanghai China. For induction of collagen‐induced arthritis (CIA) in C57 mice, chick type II collagen (Chondrex) emulsified in an equal volume of Freund's complete adjuvant (CFA) (Chondrex). Mice were immunized with 100 μl of the emulsion intradermally at the base of the tail. At day 21 after the first immunization, mice received another booster injection with an emulsion of collagen and CFA. Arthritis will develop in 28–35 days following the first immunization. Acute colitis was induced by treatment of mice with 3.5% (w/v) DSS  (MW 36–50 kDa) dissolved in sterile, distilled water for 7–9 days. The mice received the inhibitor as indicated by oral administration. For the mouse model of psoriasis, mice were administered a daily topical dose of 62.5 mg of the cream containing 5% imiquimod (Mingxinlidi Laboratory) on hair‐free back of mice for 7 days and treated with the inhibitor as mentioned before.5.2post hoc comparisons and Student's t‐test was applied when comparing between two groups. *p < 0.05, **p < 0.01, ***p < 0.001.All data were presented as the means ± SD and all data analysis was done by GraphPad Prism 5 software. Statistical analyses were performed using one‐way analysis of variance with Tukey's test for All data in our study are available upon request.The Research Ethics Committee of Fudan university granted ethical approval for the use of human subjects. All participants gave informed consent to be included in the study.Animal studies in nude mice were approved by the Institutional Animal Experiment Committee of Fudan university and carried out in accordance with the “Guide for the Care and Use of Laboratory Animals” prepared by the National Academy of Sciences and published by the National Institutes of Health (NIH publication 86‐23 revised 1985).The authors of this manuscript have no conflicts of interest to disclose.Supporting informationClick here for additional data file.


This structural motif can be reproduced by a reaction of trimethylsilyl compounds of methane, halogens, or pseudo‐halogens with excess sodium tert‐butoxide. A nucleophilic substitution releases the corresponding anion, which is then encapsulated by the sodium alkoxide units. The compounds are soluble in hydrocarbon solvents, enabling studies of solutions by high‐resolution NMR spectroscopy and IR/Raman studies of the crystalline materials.Alkali metal alkoxides are widely used in chemistry due to their Brønsted basic and nucleophilic properties. Potassium alkoxides assist alkyllithium in the metalation of hydrocarbons in Lochmann‐Schlosser‐bases. Both compounds form mixed aggregates, which enhance the thermal stability, solubility, and the basic reactivity of these mixtures. A very unusual spherical mixed alkoxy aggregate was discovered by Grützmacher et al., where a central dihydrogen phosphide anion is surrounded by a highly dynamic shell of thirteen sodium atoms and a hull of twelve  Sodium alkoxide with a pinch of salt: The in situ release of organic or inorganic anions from silyl compounds allows for their encapsulation in a sodium alkoxide shell. These spherical mixed aggregates incorporate anions ranging from the organic and basic methyl anion, halides, and pseudo‐halides to the nitrate anion. In this form, such anions can be studied as isolated entities unaffected by the influence of strongly coordinating solvents. Their roles in synthetic chemistry range from precursor for metal oxide layers,n‐butyllithiumnC4H9] and potassium tert‐butoxide [KOtBu].2tBu, LiNp] was used in combination with KOtBu, the product of this mixture could be identified as mixed aggregates combining all four components, lithium, potassium, alkyl, and alkoxy groups side by side.iso‐butyllithium,tert‐butyllithium,2SiMe3], despite its commercial availability. Other useful properties of the trimethylsilylmethyl group are based on the carbon‐silicon bond polarity and negative hyperconjugation2tBu>CH2SiMe3), or advantageous crystallization behavior due to the group polarities.Alkali metal 2SiMe3],[2SiMe3],[2SiMe3],2SiMe3]4Np(OtAm)3] (OtAm=OCMe2Et).2SiMe3] and an excess of [KOtBu] or [KOtAm], only intractable products were obtained. The use of the corresponding sodium compounds, NaCH2SiMe3 [NaR] and NaOtBu, turned out to be more successful. Heating of solutions in n‐hexane or n‐heptane resulted in clear, yellowish solutions, which produced yellowish octahedral crystals of compound 3@1CH : 0.70 g, 60 %) with the composition [Na13(CH3)(OtBu)12]  is expressed in it hexameric2O2 four‐ring and its extension are found as central structural motif, which can be described as ring‐laddering.The same result was observed when LiCH3@1CH is a close analogue of a predecessor compound reported about as 2@1PH by Grützmacher et al. in 2010 as sodium alkoxide/dihydrogen phosphide complex with the formula Na13(PH2)(OtBu)12.a between 19 and 20 Å (2@1PH: 19.3622(3) Å at 30 K; 3@1CH: 19.4734(21) Å at 173 K) with a face‐centered cube packing. The peripheral region of the spherical molecule is formed by a symmetrical arrangement of twelve tert‐butoxy groups in both cases 12]+ aggregate. However, due to the profound disorder, the central anion appears as an indefinable atom. In addition, parallel to 2@1PH, the positions of the attached hydrogen atoms in 3@1CH cannot be determined. As the X‐ray crystallography supplies no definite information about the central anion, detailed spectroscopic information was consulted in this regard. On first inspection, the 1H NMR spectrum of solution of these crystals in deuterated cyclohexane [C6D12] revealed merely a singlet for the OtBu protons. However, the signal is slightly shifted to lower field in respect to pure NaOtBu in the same solvent . A similar shift is observed in solutions of deuterated benzene [C6D6] , which speaks against the presence of pure NaOtBu. Closer inspection of the 1H NMR spectra revealed a second weak singlet (intensity ∼1 : 40) in the far high field . The non‐identity with NaOtBu suggests that the tBu signal and the high field signal belong to the same molecule. This data would be in accordance with a mixed sodium alkoxide/hydride aggregate. Comparable lithium aggregates were reported by Thomas et al., which were characterized by 2H and 7Li NMR spectroscopy as Li10H(OtBu)9 (LiH ⋅ 9LiOtBu) or Li12H(OtBu)11 (LiH ⋅ 11LiOtBu).13C satellites with a coupling of 96 Hz at the high field signal and a cross peak in the HSQC spectrum . The presence of a methyl entity was revealed by a 1 : 3 : 3 : 1 quartet in a proton coupled 13C NMR spectrum =100 Hz), and the occurrence of CH3D1 with D2O. The composition of 3@1CH qualifies it as a proper alkyl/alkoxy mixed aggregate, though the endohedral position of the methide group should hamper its basicity.1H NMR of 3@1CH in [D8]toluene.1H NMR measurement in [D8]THF of 3@1CH demonstrated its complete destruction by this coordinating solvent.This interpretation was substantiated by a positive‐phased signal in a 3SiCH2 group, the destruction of which would be in accordance with the lack of results of the corresponding Lochmann‐Schlosser chemistry. To test this hypothesis, we used α‐mono‐deuterated trimethylsilylmethyllithium [LiCHDSiMe3] (degree of deuteration of 80 %). However, after the reaction with excess NaOtBu , only small amounts of the mono‐deuterated 2D@1CH (<20 %) beside 3@1CH could be detected in the 1H NMR with secondary isotopic shift2ΔH(D)=+0.035 ppm. In contrast, when α‐ and γ‐deuterated trimethylsilyl‐methyllithium [LiCHDSi(CH2D)3] with 70 % deuteration was used, the degree of deuteration in 2D@1CH was retained methyl sodiumThese results clearly point towards the trimethylsilylmethyl group as source of the methyl anion in 1J(1H‐13C) coupling constant of 96 Hz, which is comparable to the corresponding coupling in methyllithium [LiMe] with 98 Hz,2J(H−H) coupling of 10 Hz (derived from the corresponding 2J(H−D) coupling of 1.5 Hz) is lower than the value for methyllithium with 13 Hz.3@1CH offers the opportunity to study an alkali metal methide compound in solution by high‐resolution NMR spectroscopy, without the presence of a donor solvent. Carbon‐sodium interactions are considered predominantly ionic; the coordination of the central methide by 13 highly mobile sodium atoms in 3@1CH makes the description as highly polar multi‐centered covalent interaction even less applicable.The observed 3@1CH and 3@1CD (the latter was obtained by reaction of fully deuterated trimethylsilyl methyllithium [LiCD2Si(CD3)3] with excess NaOtBu; yield: 0.14 g, 36 %), show significant differences from NaOtBu. However, no absorption band could be assigned to the corresponding vibrations of the CH3 or CD3 anions.The IR and Raman spectra of both Neither spectroscopic data nor X‐ray diffractometry allow to draw valid conclusions about the conformation of the methyl anion. Regarding the low inversion barrier of the free methide anion3@1CH from sub‐ideal ratios of NaR and NaOtBu  regularly led to a second high field CH3 singlet signal of lower intensity in the 1H NMR spectrum at −3.25 ppm in C6D12 or −3.13 ppm in C6D6. When present, this signal is accompanied by two other singlets , similar to the signals of pure NaR6D12: CH2: −2.23 ppm, SiMe3: 0.05 ppm; in C6D6: CH2: −2.44 ppm, SiMe3: 0.15 ppm). This result is consistent with the replacement of a peripheral OtBu group by a CH2SiMe3 group, associated with a low field shift of the 1H NMR signal of the central methide anion. The possibility of another unknown central anion causing the lower field signal was ruled out by the addition of NaR to a pure sample of 3@1CH, which intentionally replicated the signal pattern. The low solubility of NaR in alkanes prevents the addition of more than one R group to 3@1CH. The partial or complete replacement of OtBu groups in 3@1CH was achieved by another sodium alkoxide, sodium 1‐methylcyclohexanolate3@1CH transformed the original methide singlet in the 1H NMR by a new signal of apparently high‐multiplicity (e. g. nonet or higher), showing a striking resemblance to the 2H NMR signal of Li10H(OtBu)9 and Li12H(OtBu)11, caused by the coupling with 6Li.6D6: 9.6 Hz; C6D12: 4.6 Hz), which is not consistent with a proton‐proton coupling but with a roughly proportional change of the chemical shift by a step‐by‐step exchange of OtBu groups with OMeCyc groups in 3@1CH.Earlier attempts to produce 3@Na13(OMeCyc)12] is formed in analogy to 3@1CH by a reaction of NaR with an excess of NaOMeCyc, as confirmed by 1H NMR spectroscopy (OMeCyc: 0.9–1.8 ppm). When this compound is mixed with 3@1CH in C6D6, an exchange of alkoxy groups between these compounds can be observed by 1H NMR spectroscopy 12) and −3.23 ppm (3@1CH) after several minutes. It is possible to assign these 13 roughly equidistant resonances to mixed alkoxy species of the formula CH3@Na13(OtBu)12‐x(OMeCyc)x, with x=0 (3@1CH) to x=12 (CH3@Na13(OMeCyc)12). The intensities of the peaks, each representing several conformational isomers, follow a statistical Gauss contribution; the position of the maximum depends on the ratio of the starting materials. So far, it is not clear how changes in the alkoxy shell of 3@1CH influence the NMR chemical shift of the methide group. Possible influential properties are the molecular weight of participating groups, group basicity, and/or changes in interactions with the sodium cations affecting their dynamic movement. However, the gradual change in the composition of alkoxy sphere in 3@1CH resulting in a proportional change of the chemical shift of the methide anion is consistent with its central position inside the spherical arrangement consisting of twelve alkoxide units. To test whether the exchange of alkoxide group proceeds through a dissociative or associative process, additional NaOtBu was added to freshly produced mixtures of 3@1CH and CH3@Na13(OMeCyc)12, which were supposed to accelerate the reaction in case of an associative path. Beside a significant deceleration of the alkoxide‐exchange, changes in the evolution of the signal patterns are also observed  between the two original methide 3SiX] in reactions with excess NaOtBu would demonstrate that other anionic units can be released in situ by nucleophilic substitutionX@1] as well. In this case spherical mixed aggregates emerge as ubiquitous structural motifs for the encapsulation of small organic and inorganic anions.As the source of the methide anion is the trimethylsilylmethyl group [R], its formation requires the cleavage of a C−Si bond13C‐enriched trimethylsilylcyanide [Me3Si13CN] in a reaction with excess NaOtBu in n‐hexane; heating resulted in a clear solution, which afforded colorless octahedral crystals of 13CN@1 . X‐ray diffractometry revealed a cubic cell with the cell constant very close to 3@1CH and 2@1PH (a=19.430(3) Å, 173 K, Table To monitor the occurrence of this reaction by NMR spectroscopy, we used 3@1CH and 2@1PH, the structure reveals a disorderly icosahedral arrangement of OtBu groups and thirteen sodium atoms on twenty positions. The central electron density can be interpreted as diatomic unit, but the profound disorder of the molecule prevents a reliable assignment. 1H NMR in C6D6 revealed an OtBu singlet at 1.39 ppm. The corresponding 13C NMR spectrum shows a resonance at 164.7 ppm for the CN group beside the two OtBu signals at 37.7 (OCMe3) and 66.6 ppm (OCMe3). The 13C resonance of 13CN is very similar to the corresponding sodium salt in D2O (164.8 ppm).CN@1  were obtained using the same protocol as for 13CN@1. The IR and Raman spectraCN@1 and 13CN@1 are almost identical to 3@1CH. However, additional bands of the C≡N triple bond are observed at 2079 cm−1 (CN@1) or at 2036 cm−1 (13CN@1), respectively.−1.In analogy to X@1 . X‐ray crystallography revealed cubic cells with similar cell constants compared to 2@1PH, 3@1CH, and CN@1. Plotting the corresponding cell volumes against the calculated anion‐volumes .Other trimethylsilyl compounds of inorganic ions were tested in similar reactions. However, the halides as obvious candidates do not allow the definite characterization of 1 Scheme , producis Figure , places 3SiF. When Ph3SiF was used instead, large colorless blocks were obtained. X‐ray crystallography revealed the product as Na11F(OtBu)10, 2‐F (OtBu)10, 2‐OH (space group 1Pca2).2‐OH is described as a fusion of a [4.4.4.4] fenestrane, centered with the hydroxide anion and a distorted hexaprismane. For compound 2‐F, a modified description is suggested: 2‐F and 2‐OH share a square antiprismatic arrangement of eight sodium atoms; one of the square faces  is μ4‐capped and four of the eight triangular faces are μ3‐capped by four oxygen atoms of OtBu groups. The fluoride anion is situated inside the square antiprism close to the central square face  −2.4399(9) Å), which is also part of a virtual distorted Na8‐cube, with the five residual faces μ4‐capped by the oxygen atoms of OtBu groups. However, the positions of two of the peripheral four sodium atoms are generated by a positional disorder of Na11, which also affects the position of the two other sodium atoms (Na9 and Na10) of the same face. In fact, two Na3 triangles are superimposed (approximately occupation: 70/30 %), presenting a distorted Na4 trapezoid. Although the 11 sodium atoms are not dynamically distributed over 12 positions, compound 2‐F gives an impression of how the formal addition of two additional NaOtBu units and the replacement of fluoride by a larger and softer anion X− leads to the transformation of the OtBu square antiprism into a pentagonal antiprism of an icosahedron, resulting in the formation of the spherical and highly dynamic arrangement of X@1.Compound 2‐F, Cl@1, Br@1, and I@1 are sufficiently soluble in C6D6 to allow their characterization by NMR spectroscopy. The 1H NMR spectra exhibited only singlet signals for the OtBu protons . The NMR spectra of the quadrupolar halides  yielded sharp resonances with linewidths comparable to the signals of the references in D2O . This indicates a highly symmetric environment of the halide ions in respect to the NMR time‐scale, which is in accordance with a highly dynamic movement of the 13 sodium atoms sharing 20 positions. The chemical shift of 2‐F in the 19F NMR with −223.3 ppm is very similar to NaF3). In contrast, the signals of the heavier halide compounds are shifted considerably to the high field region  compared to the solid‐state MAS NMR spectra of the corresponding sodium salts . These findings suggest that the differences in the structures of 2‐F and Cl@1, Br@1, and I@1 continue to exist in soluble phase.Similar to the compounds discussed before, Halide anions as central anions surrounded by a distorted spherical sodium/europium alkoxide aggregate@1, is also applicable to produce the pseudohalide compounds OCN@1, SCN@1, and 3@1N  were studied by NMR and IR/Raman spectroscopy. All three compounds produced singlet OtBu resonances in the 1H NMR spectra . The three linear three‐atomic units showed characteristic bands in the vibrational spectra , which are in good accordance with the spectra of the corresponding sodium salts. is available by a reaction of silver nitrate [AgNO3] with trimethylsilyl chloride [Me3SiCl].3SiNO3 with excess NaOtBu produced colorless octahedral crystals of 3@1NO . C6D6 solutions of these crystal showed single resonances at 1.36 ppm in the 1H NMR spectrum (OtBu). The central nitrate ion is identified by characteristic bands in the vibrational spectra .[153@1NO. The corresponding trimethylsilyl nitrate [Me3Si15NO3] was accessible by a reaction of 15N‐enriched ammonium 15N‐nitrate with bis(trimethylsilyl) sulfate.15N NMR signal of 153@1NO could be detected as a singlet resonance at −6.8 ppm.as 1369 cm−1; γ 815 cm−1); the symmetric νs vibration visible in the Raman spectrum at 1076 cm−1 is not affected.As it became clear that large, linear anions such as thiocyanate, or chemically reactive anions such as azide can be accommodated by spherical mixed aggregates, the question was raised if even larger and less inert anions are candidates for inclusion in such aggregates. The nitrate anion with its planar four‐atomic arrangement and its oxidizing potential offers interesting additional properties. Trimethylsilyl nitrate13(OtBu)12]+ unit (+1), it is premature to speculate about systematic influences on the properties of the corresponding anions. Possible effects of the highly dynamic Na13 shell on the electronic properties 3@1CH (1H and 13C), and the halide anions in Cl@1, Br@1, and I@1 show characteristic high‐fields shifts of the corresponding resonances. Remarkably, the 35Cl, 79Br, and 127I NMR data suggests that the environment of the halide anions is highly symmetric in the NMR time‐scale, as it is reflected by the sharp singlet resonances of these quadrupolar nuclei allowing their easy detection by NMR spectroscopy. Nevertheless, the observed change of the 1H chemical shift following changes of the sodium alkoxide capsule demonstrates its significance for interactions of the central ion with the outside. The high sodium cation mobility is a consequence of the energetic equivalence of the 20 possible positions and low activation barriers between them. Compound 2‐F, which is structurally well defined and considerably less disordered, also exhibits 12 possible positions for 11 localized sodium cations, resulting in the disorder of four sodium cations over three positions. Further studies will have to show whether structural vibrations/deformations of the alkoxy group arrangement support this dynamic behavior in X@1.With only some examples of anions encapsulates by a spherical cationic [Na2@1PH and 3@1CH can be expected to be induced by the interaction with the highly dynamic environment of the sodium cations, too. The dynamic environment possibly hinders the detection of C−H bonds in 3@1CH by IR/Raman spectroscopy by massive broadening of the corresponding bands. The vibrations of heavier atoms are affected in a much smaller scale. In this respect parallels to the corresponding sodium salts in solid or molten state can be drawn. The vicinity of equidistant 13 sodium cations (in averaged 20 positions) should result in a pulling or pressing effect onto the central anionic molecule, depending on the size (longest axis or diameter). However, the vibrations of the central anions observed by IR or Raman spectroscopy are very similar to those of sodium salts, solutions, or gas phase theoretical calculations of the corresponding anions. The assumption of a flexible Na13(OtBu)12+ capsule, which is adaptable to an ellipsoid deformation, would be in line with these observations. This deformation would also explain, why the introduction of larger linear anions has only a minor effect on the corresponding cell parameters of the compounds . For anions such as chloride or larger, the electrostatic attraction of the ions is weak enough and the Pauli repulsion between the atomic cores is strong enough to allow an arrangement with a high coordination number . Calculations involving point charges reveal that the electrostatic potential inside an averaged spherical arrangement similar to +1 is comparably flat over a large diameter. This observation can be traced back to an additive overlay of the individual charges at the center of the structure. This eventually leads to a weaker increase of attractive forces when the central ion is shifted away from the center.The flexibility and adaptability of the sodium alkoxide shell towards the encapsulated anion also play a pivotal role in the process of its trapping. The hydroxide or fluoride anions in compound 3@1PH by Grützmacher et al. into a whole family of compounds X@1 was achieved by replacing the central ion with a range of halide anions, pseudohalide anions, methide, or nitrate. The in situ release of the corresponding anion from a silyl compound enable its trapping by an excess of sodium alkoxide. The presented examples range from strongly reducing and highly basic anions (methide) to anions of strong acids with oxidizing properties (nitrate). The number of atoms in the anionic center ranges from one  up to four (methide and nitrate). If the size of the anion falls below the size of chloride, the mixed alkoxide aggregates adapt a different, well defined arrangement of the formula Na11X(OtBu)10 .The evolution of the original phosphide compound X@1 arises not solely from the fact that it is possibly present in small amounts in many reported syntheses using sodium alkoxide, without having been detected or recognized. This can include the use of sodium alkoxides for the synthesis of alkyl or silyl ethers, the formation of metal alkoxides from the corresponding halides, or the formation of the sodium alkyl compounds starting from alkyllithium and sodium alkoxides. In addition, the encapsulation can lead to an unintentional masking of anions on one hand or their unintended introduction into reaction mixtures on the other hand. The awareness of these effects may help to understand undesired reaction outcomes and to improve corresponding synthetic procedures. The results concerning 3@1CH also explain the lack of Lochmann‐Schlosser superbase chemistry of the otherwise very useful and versatile trimethylsilylmethyl group.The relevance of alkoxide compounds of type The vagueness and lack of crystallographic accuracy of this class of alkali metal alkoxide compounds are richly compensated by several singular properties, which are rarely seen in this combination. The inverse‐micellar arrangement encapsulates anions in a way that enables their solubilization in non‐polar media; the release of the anion can be achieved in highly polar solvents such as THF. Furthermore, the encapsulation enables the study of such otherwise insoluble anions in solution by high resolution NMR or UV/Vis spectroscopy. This option is even more intriguing, when the in situ isolation and characterization of highly reactive and otherwise not isolable anions is rendered possible by this approach. However, the influence of the highly dynamic capsule on the spectroscopic properties is not yet fully understood.The modification of both the central ion and the peripheral alkoxy groups offers the opportunity to evolve the spherical entities into larger structures, retaining the high sodium cation mobility for ion‐conducting applications. The replacement of the peripheral alkoxy groups by other available groups will introduce new properties, such as redox‐activity, or super‐basicity when organic alkyl groups are introduced.Crystallographic data: Deposition numbers 2061407, 2061408, 2061409, 2061410, 2061411, and 2061412 contain the supplementary crystallographic data for this paper. These data are provided free of charge by the joint Cambridge Crystallographic Data Centre and Fachinformationszentrum Karlsruhe Access Structures service.The authors declare no conflict of interest.As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re‐organized for online delivery, but are not copy‐edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors.Supporting InformationClick here for additional data file.


Herein, a novel lithium–oxygen full cell coupling a lithium anode protected by a composite layer of polyethylene oxide (PEO)/lithium aluminum titanium phosphate (LATP)/wax to a LiOH‐based cathode is constructed. The protected lithium is stable in air and water, and permits reversible, dendrite‐free lithium stripping/plating in a wet nonaqueous electrolyte under ambient air. The LiOH‐based full cell reaction is immune to moisture (up to 99% humidity) in air and exhibits a much better resistance to CO2 contamination than Li2O2, resulting in a more consistent electrochemistry in the long term. The current approach of coupling a protected lithium anode with a LiOH‐based cathode holds promise for developing a long‐life, high‐energy lithium–air battery capable of operating in the ambient atmosphere.Realizing an energy‐dense, highly rechargeable nonaqueous lithium–oxygen battery in ambient air remains a big challenge because the active materials of the typical high‐capacity cathode (Li A highly rechargeable lithium‐air battery operating directly in ambient environment is successfully demonstrated by coupling a LiOH‐based cathode and an air‐stable lithium anode with a composite protective layer. Key advantages of the system include: 1) outstanding electrochemical stability; 2) Li dendrite‐free; 3) superior resistance to humidity (99%) and CO2; 4) being applicable to highly wet electrolytes (up to 50vol%). But none of these electrode materials are air stable. Li2O2 and Li2O would spontaneously react with H2O and CO2 to form LiOH and eventually Li2CO3, the latter inducing high overpotentials on recharging and causing further parasitic reactions to carbon cathodes and electrolytes , especially moisture, alongside the conventional problems pertaining to an unstable solid‐electrolyte interphase (SEI) and Li dendrite formation  lithium–air battery.To achieve stable electrochemical Li stripping/plating, many previous studies have employed solid‐state Liatteries.27 The2 contamination compared to Li2O2 and Li2O  have been demonstrated as reversible four‐electron oxygen reduction (ORR) and evolution reactions (OER), i.e. CuI‐complex enzyme, sodium trifluoromethanesulfonate as additives in nonaqueous electrolytes or the use of solid catalysts . However, no study so far has evaluated the electrochemical stability of a LiOH‐based cell reaction in ambient air, and investigated whether or how H2O and CO2 in air would alter the nature of the reaction product.At the cathode, LiOH being an alternative active material, is theoretically immune to moisture and more resistant to COO Figure .3] 3 2 co2, H2O, CO2 with mediator or enzyme additives and shuttling of these redox species; it also exhibits a consistent LiOH‐based electrochemistry throughout the whole capacity with low overpotentials and relatively good rechargeability. As such, it allows a true assessment of air effects on the stability of this cathode electrochemistry in both short and long terms. In addition, we have designed a hierarchical multifunctional layer on the Li anode to enable stable operation of a full battery in ambient air , chemical titration, X‐ray diffraction (XRD), solid state nuclear magnetic resonance (ssNMR), Fourier transformed infrared spectroscopy (FTIR), X‐ray photon‐electron spectroscopy (XPS), and so on  on the electrochemistry of two cell systems: one uses Super P (SP) carbon as the cathode and anhydrous Lithium bis(trifluoromethanesulfonyl)imide in dimethyl sulfoxide (LiTFSI/DMSO) as the electrolyte, and the other uses a ruthenium decorated SP (Ru/SP) cathode  atmosphere caused a few notable changes to the electrochemistry of cells using SP cathodes  per cycle for around 100 times, before the capacity starts to fade. The above data demonstrate that the Ru/SP‐catalyzed reaction at the cathode possesses a higher electrochemical stability and better rechargeability in air than the typical Li2O2‐based cell reaction.Switching to a dry air  to approximately four electrons per O2 ; this mixed and evolving electrochemistry using a Ru/SP cathode hinders a clear‐cut comparison of air resistance between the Li2O2‐ and LiOH‐based systems, and thus a SP cathode, instead, has been used for comparison.It is worth mentioning that we have also investigated the electrochemistry of cells using Ru/SP cathodes and Figure 2, consistent with dominant Li2O2 formation. Chemical titration of the discharged electrodes in dry air , together with LiOH (10%) and Li2CO3 (15%) due to side reactions, the quantities of these by‐products being 2% and 6% higher than those obtained in pure O2 , and that around 2% of the products was Li2CO3, 7.5 times lower than the Li2CO3 amount detected in the Li2O2 case. No Li2O2 was identified to the detection limit of the titration method. The presence of Li2CO3 (characteristic absorption bands at 857 and 1400 cm−1) was also confirmed by FTIR measurements on discharged samples in air  the influence of dry air and ambient air on LiOH‐based electrochemistry are basically the same during discharge, both leading to a small increase in Li2CO3 formation, and moisture in air does not alter the reaction product at cathodes; 3) the effect of air is more adverse on the process of Li2O2 formation than LiOH formation, with the former showing a rise in Li2CO3 quantity 3 times that of the LiOH case. Upon charging the Ru/SP cells, no oxygen was released . Some CO2 evolution has been recorded, corresponding to the 3.65 V plateau, which is in an agreement with previous assignment of this plateau to Li2CO3 decomposition. The amount of released CO2 in the LiOH case was much less than that in the Li2O2 case  becomes the other major process. On the other hand, for cells using Ru/SP cathodes and wet electrolytes, the prevailing electrochemistry during discharge at the fourth (90%) and seventh cycle (≈88%) is still LiOH formation in both dry and ambient air  and removal were the main processes over 12 discharge–charge cycles, further supporting good rechargeability.XRD, ssNMR, and SEM characterizations also support that the electrochemistry of Ru/SP cells is predominated by LiOH formation and decomposition over extended cycles in ambient air. Over 30 cycles, the only observable Brag reflections Figure  at the eH Figure  illustra  an2, which tends to cause more Li2CO3 formation during discharge and more CO2 evolution on recharging. The Ru/SP‐catalyzed LiOH electrochemistry is more resistant to this CO2‐induced conversion of discharge product and is immune to moisture in air, exhibiting a better electrochemical stability than Li2O2. Next, we begin to uncover the origins of Li2CO3 formation and discuss the key factors modulating the CO2 effect on the LiOH‐based electrochemistry.Thus far, it has become clear the prominent air constitute that impacts on the cathode electrochemistry is CO2 to form Li2CO3 via reaction 2, 2/CO2 batteries employing much higher CO2 concentrations (>10%) in the atmosphere. In the current study, the concentration of CO2 for cell reactions used was only 0.038%, the same as in ambient air. Typically, no appreciable drop in the CO2 OEMS baseline has been observed during the 1st cell discharge, which however was not the case in subsequent discharges. Figure 2 in cases with and without a resting period between the prior charge and the following discharge. During a cell charge followed by a resting period  indicating 0.62 µmol more CO2 being consumed, whereas in the Ru/SP cells, this quantity of electrochemical reduced CO2 following a charge was three times smaller  was electrochemically reduced again , faster cycling rates, and deeper discharge capacities tended to lead to smaller fractions of Li2CO3.Li2O2 and LiOH, the former being more vulnerable to CO2 contamination, thus forming more Li2CO3. As the water concentration was increased , where it is known that DMSO is unable to form a stable SEI on lithium and water reacts violently with lithium releasing heat and H2 gas  proof to liquid electrolyte so that the protected Li anodes can be compatible with a wide range of nonaqueous electrolytes, even those with high water contents; 3) supporting a high Li+ conductivity; 4) possessing a stable interface between lithium metal and the protective layer; 5) having a sufficient mechanical strength so that Li dendrite formation is suppressed. Given the above consideration, we have constructed a nonporous composite protective layer  repelling Nr Figure , which i and a gapless contact with the LATP layer for Li+ conduction. The nonporous, mechanically strong LATP‐wax composite layer is designed to protect the rest of the Li anode from air and reactive species in electrolytes, as well as help suppress Li dendrite growth. Ideally, the thickness of the all‐solid‐state composite layer should be made thinner (<50 µm) in order reduce resistance for charge transfer and improve the rate capacity of the lithium anode. Conventional polymers containing polar segments such as PEO, PAA (Polyacrylic acid), cannot replace the role of wax, because these polymers are microporous and permeable to water vapor and electrolyte solvents. During cell operation, components of air and liquid electrolytes are not allowed to get across this protective layer  in air started to show severe capacity fade and larger polarization after just 5 cycles , with one discharge and two charge plateaus at 2.7, 3.2 and 3.65 V, respectively; the electrochemical profiles were similar to those observed in half cells where lithium iron phosphate was used as the counter electrode , and compared to results obtained using bare lithium as anodes. Without Li protection, the full cell using wet electrolytes  of LATP surfaces, suggesting that LATP was not reduced by lithium dendrite. The appearance of protected Li anodes after cycling remained white  and growing on top of the surface  with substantial amount of water. The current approach of coupling a protected lithium anode with a LiOH‐based cathode holds promise for developing a long‐life, high‐energy lithium–air battery in the ambient atmosphere.In conclusion, we have shown that the most prominent constitute in air that affects the OThe authors declare no conflict of interest.Supporting InformationClick here for additional data file.Supporting InformationClick here for additional data file.