Application of Isomorphic Anion Incorporation to Enhance Electrochemical Performance in Vanadium-Based NASICON Cathode Materials

Abstract

Polyanionic fluorophosphate NaVPO4F is an ideal cathode material for high power sodium-ion batteries due to its high theoretical specific capacity and operating voltage. However, its practical application has been hindered by low electronic conductivity and limited ionic mobility. To address this issue, this study successfully prepared SiO44- incorporating NaV(PO4)1-x(SiO4)xF cathode material. Research findings indicate that the incorporation of SiO44- not only markedly reduces the material's diffusion activation energy but also enhances the kinetics of sodium-ion transport. Consequently, the modified NaV(PO4)0.9(SiO4)0.1F (NVPF-SiO10) cathode material exhibits a several orders of magnitude improvement in sodium-ion diffusion rate, leading to superior rate performance (achieving a specific capacity of 89.3 mAh g-1 at 30 C) and exceptional cycling stability (retaining 75.3% capacity after 2000 cycles at 10 C). Furthermore, when integrated into full battery with hard carbon, the battery exhibits exceptional reliability and stability for high-performance applications.