Entropy‐Stabilized NASICON Cathodes Enabling Efficient V ⁴⁺ /V ⁵⁺ Redox and Unprecedented Cycling Durability for Sodium‐Ion Batteries

ABSTRACT Constructing cathode materials combining high operating voltage with long‐term stability is critical for sodium–ion batteries (SIBs). Although Na 3 V 2 (PO 4 ) 3 (NVP) is regarded as a promising candidate, its practical application is limited by low intrinsic electronic conductivity and structural distortion at high voltages. Herein, we regulate the configurational entropy by co–introducing Cr 3+ , Al 3+ , Mg 2+ , Mn 2+ and Cu 2+ into NVP to develop a novel Na 3.18 V 1.7 (CrAlMgMnCu) 0.3 (PO 4 ) 3 (NVMP) cathode. Through the successful activation of the reversible V 4+ /V 5+ redox couple at ∼4.0 V, the configurational entropy regulation strategy in NVMP effectively enhances the intrinsic electronic conductivity and reaction kinetics. Concurrently, it optimizes the phase transition behavior during (de)intercalation, which collectively contributes to superior rate capability and long–term cycling stability. As a result, NVMP exhibits an average operating voltage of 3.64 V and a high energy density of approximately 425 Wh kg −1 . Notably, it retains 95.9% of its initial capacity after 5000 cycles at a high rate of 20 C, demonstrating exceptional cycling stability. This work provides valuable insights for designing high–performance NASICON–type cathodes for SIBs.