Suppressing Anti‐Site Defects via Entropy Regulation Enables High‐Rate Sodium‐Ion Battery Cathodes

Abstract NASICON‐type Na 4 MnV(PO 4 ) 3 (NMVP) holds great promise for sodium‐ion batteries (SIBs) due to its high dual‐electron redox capability. However, its practical application is hindered by inherent structural and kinetic limitations, including Na/Mn anti‐site disorder, Jahn–Teller distortions induced by Mn 3+ , and sluggish Na + transport, which ultimately lead to rapid capacity degradation and poor cycling stability. Herein, this study proposes an entropy‐regulation strategy that leverages the synergistic effects among multiple elements to suppress structural distortion during cycling and enhance multi‐electron redox activity and reversibility. Density functional theory (DFT) calculations reveal that the high‐entropy configuration increases the formation energy of Na/Mn anti‐site defects, effectively mitigating the occurrence of Na/Mn anti‐site defects. The resulting high‐entropy NMVP (NMVP‐HE) exhibits outstanding rate capability (44.8 mAh g −1 at 100C) and exceptional long‐term cycling stability (75.4% capacity retention after 20 000 cycles). Additionally, the NMVP‐HE//hard carbon (HC) full cell achieves a high energy density of 255.0 Wh kg −1 (based on cathode and anode mass) and excellent cycling stability. This work presents entropy regulation as a powerful and versatile strategy to unlock fast kinetics and long‐term stability in NASICON‐type cathodes, offering a viable pathway toward high‐performance SIBs for practical applications.