Large-scale synthesis of few-layered copper antimony sulfide nanosheets as electrode materials for high-rate potassium-ion storage.
Metal chalcogenides (MCs) have received widespread attentions in potassium ion storage, due to their high theoretical specific capacity and low cost. However, practical applications are still a challenge because of the slow diffusion rate and large ionic radius, leading to dramatic volume expansion and slow rate performance. Herein, we introduce a simple and large scale solvothermal method to synthesize high-quality two-dimensional (2D) layered CuSbS2 nanosheets with a thickness of about 5 nm. The thin 2D layered structure has a weak van der Waals gap and a large exposed surface area to contact the electrolyte and promotes rapid K+ diffusion kinetics. In addition, the in-situ copper exsolution during potassiation process enhances the rate capability of K+ storage. CuSbS2 half cells exhibited excellent rate performance, delivering specific capacities of 573, 505, 476, 230, 177 mAh g-1 at current densities of 0.1, 0.5, 1, 5, 10 A g-1, respectively. The unique K+ electrochemical storage mechanism and resistance change during reaction process was revealed in detail by operando XRD, XPS and TEM. Finally, potassium ion hybrid capacitors (PIHCs) with CuSbS2 nanosheets as anode and AC as cathode demonstrated excellent performances with the maximum energy density of 127 W h kg-1 and the power density of 2415 W kg-1, providing an example of rationally design a high rate battery-type PIHC anode.
['Chang|Che-Bin|CB|', 'Chen|Kuan-Ting|KT|', 'Tuan|Hsing-Yu|HY|']
Nanosheets High-rate Metal chalcogenides Potassium ion storage Hybrid capacitors