DeeplyNesting Zinc Sulfide Dendrites in TertiaryHierarchical Structure for Potassium Ion Batteries: Enhanced Conductivityfrom Interior to Exterior

Transition metal sulfides are deemed as attractive anode materials for potassium-ion batteries (KIBs) due to their high theoretical capacities based on conversion and alloying reaction. However, the main challenges are the low electronic conductivity, huge volume expansion and consequent formation of unstable solid electrolyte interphase (SEI) upon potassiation/depotassiation. Herein, zinc sulfide dendrites deeply nested in the tertiary hierarchical structure through solvothermal-pyrolysis process are designed as an anode material for KIBs. The tertiary hierarchical structure is composed of the primary ultrafine ZnS nanorods, the secondary carbon nanosphere and the tertiary carbon-encapsulated ZnS subunits nanosphere structure. The architectural design of this mateiral provides stable diffusion path and enhances effective conductivity from interior to exterior for both K+ ions and electrons, buffers the volume expansion and constructs a stable SEI during cycling. A stable specific capacity of 330 mAh g-1 ...