Enhanced cycling stability of hierarchical Cu2WS4/C hollow octahedron anode for lithium-ion batteries by tuning its potential window

Abstract

Abstract The operating potential window is critical for enhancing the cycling stability of transition metal sulfide anode, because the lithium ion storage mechanism strongly depends on it. Herein, we report hierarchical hollow octahedral nanostructured Cu2WS4/C composites prepared by a polyvinylpyrrolidone-assisted solvothermal process, and their lithium-ion storage behavior. It has been demonstrated that the surfactant is a key factor that affects the morphology of Cu2WS4/C. By tuning the operating potential window, the cycling performance of Cu2WS4/C anode can be optimized, which delivers a high reversible capacity of 400 mAh/g at 0.2 A/g and displays excellent cycling stability in the optimized potential window 1.0–2.5\u202fV. The volume expansion can be accommodated by hierarchical hollow octahedral structure, suppressed polysulfides dissolution in ether-based electrolyte, and enhanced reversibility of electrochemical reaction in the optimized potential window all contribute to its superior electrochemical performance.