NASICON-Type NaVCrFe(PO): High-Voltage and High-Rate Cathode Materials for Sodium-Ion Batteries.

Cationic alteration related to a sodium super ion conductor (NASICON)-structured NaV(PO) (NVP) is an effective strategy for formulating high-energy and stable cathodes for sodium-ion batteries (SIBs). In this study, we altered the structure of NVP with dual cations, namely, Cr and Fe, to develop NaVCrFe(PO) cathodes for SIBs with high-rate capability (∼71 mAh g at 100 C) and an extreme cycle life output (∼75 mAh g with 95% capacity retention for 10,000 cycles). These excellent electrochemical properties can be ascribed to the synergistic effects of Cr and Fe in the NVP structure, as verified experimentally and theoretically.