Enhanced Electrochemical Performance of Ca-Doped NaV(PO)F/C Cathode Materials for Sodium-Ion Batteries.

NaV(PO)F (NVPF) with a NASICON structure has garnered attention as a cathode material owing to its stable 3D structure, rapid ion diffusion channels, high operating voltage, and impressive cycling stability. Nevertheless, the low intrinsic electronic conductivity of the material leading to a poor rate capability presents a significant challenge for practical application. Herein, we develop a series of Ca-doped NVPF/C cathode materials with various Ca doping levels using a simple sol-gel and carbon thermal reduction approach.