A Vanadium‐Based Fluoroxide Cathode Material for Lithium‐Ion Storage with High Energy Density

Abstract High‐performance lithium‐ion batteries (LIBs) are required for the rising energy storage demand, while their development depends mainly on cathode materials. Vanadium‐based compounds are considered to be promising due to the feasibility of multielectron reactions arising from the rich valence states of vanadium (+2 to +5). Herein, for the first time the electrochemical properties of a vanadium‐based fluoroxide, β‐KVOF 3 , as a cathode for LIBs, are reported. After optimization, a reversible capacity as high as 274 mAh g −1 , a stable 300 cycles lifetime, and an energy density comparable to LiFePO 4 (650 vs 550 Wh kg −1 ) are achieved. Experiments and simulation study of reaction mechanism illustrate that such performance originates from the reversible V 3+ /V 5+ redox reaction, high structural stability of β‐KVOF 3 , and the pseudocapacitive process during charging and discharging. This study reveals that β‐KVOF 3 is a promising cathode for Li‐ion storage and provides a new design idea for developing high‐performance LIBs cathode materials.