Sodium vanadium oxides: From nanostructured design to high-performance energy storage materials

· Be the first to have an overview of NVO materials family, which is a promising materials category for energy storage systems. · Summarize with an insight into crystal structures, morphologies, mechanisms and the electrochemical energy storage performances. · Discuss the electrochemical behaviors, which provide further insight into metal-ion storage mechanisms in NVO materials family. Developing high-capacity and low-cost cathode materials for metal-ion rechargeable batteries is the mainstream trend and is also the key to providing breakthroughs in making high-energy rechargeable batteries. Vanadium has a variety of valence states and can form a variety of vanadate structures. As a typical positive electrode material, vanadate has abundant ion adsorption sites, a unique “pillar” framework, and a typical layered structure. Therefore, it has the advantages of high specific capacity and excellent rate performance, possessing the prospect of being a large-capacity energy storage material. In this review, we focus on applications of sodium vanadium oxides (NVO) in electrical energy storage (EES) devices and summarize sodium vanadate materials from three aspects, including crystal structure, electrochemical performance, and energy storage mechanism. The recent progress of NVO-based high-performance energy storage materials along with nanostructured design strategies was provided and discussed as well. This review is intended to serve as general guidance for researchers to develop desirable sodium vanadate materials.