Simple Synthesis of K_0.5VOPO₄·1.5H₂O/Graphene Oxide Composite as a Cathode Material for Potassium-Ion Batteries

Potassium-ion batteries (PIBs) as an alternative to lithium-ion batteries have attracted much interest and develop rapidly. Among the cathode materials, polyanionic compounds present both high discharge voltage and considerable capacity owing to their unique skeleton and strong inductive effect from anion groups. In this work, a K0.5VOPO4·1.5H2O/graphene oxide composite as a polyanionic cathode material for PIBs was synthesized by a simple chemical precipitation method. The composite delivers a high capacity of 118 mA h g–1 with a competitive energy density of 402 W h kg–1. With GO modification, the composite also shows superior cycle and rate performance. The simple synthesis process and excellent performance enable it to have commercial potential in the future.