Mechanisms and principles of Na3V2(PO4)3 modification by carbon materials

Na3V2(PO4)3 (NVP) has been considered as an ideal cathode material. However, the poor intrinsic electronic conductivity restricts its development. The modification of NVP by carbon-based materials is an effective method to improve the properties. Specifically, carbon coating can significantly enhance the electronic conductivity and decline direct contact between NVP crystal and electrolyte to avoid the side effects. Carbon-based materials can establish an efficiently interconnected conductive network to facilitate the kinetic characteristics of NVP. In the process of in situ synthesis and sintering, carbon-based materials are used as structural guiding agents and templates to regulate the structure and morphology of NVP, establishing beneficial skeletons to relieve the stress caused by current stimulation on NVP crystal. In this review, three modification mechanisms of carbon coating, carbon matrix compositing and carbon-based materials controlling morphology are summarized. Furthermore, we outline the challenges and prospects of NVP electrode materials modified by carbon-based materials.