Advanced V-based materials for multivalent-ion storage applications

Multivalent ion batteries (MIBs), as promising alternative or supplementary technologies to lithium-ion batteries (LIBs), have increasingly attracted recently. Various advanced materials have been presented to pursue potential breakthroughs in energy and power. Among them, V-based materials benefiting from abundant resources, various polymorphs and valences, especially most with large interlayer spacings, are good candidates for multivalent-ion storage. However, limited by multiple inherent issues, e.g., strong electrostatic interactions, poor electronic conductivity, structure collapse or materials dissolution under battery operation, etc., various strategies have sprung many advanced materials and application, and also brought about new challenges that are in urgent need to clarify and summarize. Hence, advanced vanadium-based compounds developed for multivalent-ion storage in the past few years are selectively summarized and systematically analyzed, including vanadium oxides and sulfides, vanadates, and V-based MXenes and phosphates. Not only crystal structures and electrochemical properties, but also mainstream ion storage mechanisms are critically reviewed. Through analyzing the challenges accompanying multivalent ion storage, potential opportunities are anticipated.