Elevating cyclability of an advanced KVPO4F cathode via multi-component coating strategy for high-performance potassium-ion batteries

Developing high-performance electrode materials is crucial to the practical applications of K-ion batteries (KIBs) in large-scale sustainable energy storage systems. KVPO4F is a highly promising cathode material for KIBs, but is still limited by its poor cycle life. Herein, we design and synthesize a surface modified KVPO4F via a multi-component coating strategy. The optimized KVPO4F-based sample delivers a reversible capacity of 100 mA h g−1 and improved cycling performance with coulombic efficiencies up to 97.3%. Upon electrochemical K+ storage process, the KVPO4F cathode undergoes a completely reversible structural evolution, as determined by in-situ XRD characterization. Furthermore, a full KIB consisting of KVPO4F//hard carbon can exhibit a high energy density up to 337 Wh kg−1 as well as superior capacity retention of 86% after 200 cycles.