Pseudocapacitive Vanadium-based Materials toward High-Rate Sodium-Ion Storage

Sodium-ion battery materials and devices are promising candidates for largescale applications, owing to the abundance and low cost of sodium sources.Emerging sodium-ion pseudocapacitive materials provide one approach for achieving high capacity at high rates, but are currently not well understood.Herein, a comprehensive overview of the fundamentals and electrochemical behaviors of vanadium-based pseudocapacitive materials for sodium-ion storage is presented. The insight of sodium-ion storage mechanisms for various vanadium-based materials, including vanadium oxides, vanadates,vanadium sulfides, nitrides, and carbides are systematically discussed and summarized. In particular, areas for further development to improve fundamental understanding of electrochemical and structural properties of materials are identified. Finally, we provide a perspective on the application of pseudocapacitive materials in high-power and high-energy sodium-ion storage devices(e.g., sodium-ion capacitors).