NASICON-Type Na₃V_1.5Cr_0.4Fe_0.1(PO₄)₃: High-Voltage and High-Rate Cathode Materials for Sodium-Ion Batteries

Cationic alteration related to a sodium super ion conductor (NASICON)-structured Na 3 V 2 (PO 4 ) 3 (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 Na 3 V 1.5 Cr 0.4 Fe 0.1 (PO 4 ) 3 cathodes for SIBs with high-rate capability (∼71 mAh g –1 at 100 C) and an extreme cycle life output (∼75 mAh g –1 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. Therefore, the proposed cosubstitution method can enhance the performance of SIBs by improving their structural stability, electronic conductivity, and phase-change behavior.