High-Rate Cathode Based on Phosphate-Modified Moss-like Carbon-Coated Na3V2(PO4)2F3 Composite Materials for Fast-Charging Sodium-Ion and Zinc-Ion Batteries.

Among numerous polyanionic structural compounds (NASICONs), Na3V2(PO4)2F3 (NVPF) is considered a highly promising cathode due to its excellent electrochemical performance. However, the development of NVPF has been hindered by many factors, such as slow ion diffusion and low electronic conductivity. In this study, a phosphate-modified mosslike carbon-coated NVPF composite was successfully prepared. The unique moss-like structure effectively shortens the ion transport pathways and enhances charge transfer efficiency. Meanwhile, the in situ formed carbon layer and Na3PO4 buffer layer synergistically improve kinetics and structural stability of NVPF. When evaluated as a cathode material, it delivers a high initial capacity of 96.6 mAh g-1 at 30 C in sodium-ion batteries (SIBs) and a specific capacity of 147 mAh g-1 at 0.5 C in zinc-ion batteries (ZIBs). This study presents a successful approach to develop a cathode offering excellent performance by employing deliberate structural design and chemical adjustment at interfaces.