A high-performance solid-state synthesized LiVOPO4 for lithium-ion batteries

ε-LiVOPO4, a multi-electron cathode material for Li-ion batteries, suffers from structural disorder upon nanosizing by high-energy ball-milling, which impedes kinetics and promotes undesirable interfacial side reactions. This work presents a feasible way to decrease the disorder in the ball-milled composite of ε-LiVOPO4/C by post-annealing at 450 °C in an Ar atmosphere, with no reduction reaction caused by carbon and no particle growth. The post-annealed material shows recovered voltage plateaus, enhanced kinetics of Li diffusivity, and suppressed interfacial reactions. As a result, a high-performance solid-state synthesized ε-LiVOPO4 can be obtained, delivering a capacity of 270 mAh g−1 at C/5 with less than 4% degradation upon 100 cycles.