Folded Tangerine Peel-Like Layered Supported Na ₃ V ₂ (PO ₄ ) ₃ Composite as a High-Performance Cathode for Sodium-Ion Batteries

Na3V2(PO4)3 (NVP), featuring a Na super ionic conductor (NASICON) framework, has attracted considerable attention as a cathode material for sodium-ion batteries (SIBs) owing to its excellent structural robustness and favorable electrochemical characteristics. Nevertheless, its practical deployment remains constrained by insufficient energy density and pronounced capacity degradation during prolonged cycling. In this study, a folded tangerine peel-like layered supported carbon-coated Na3V2(PO4)3 composite was fabricated through the sol–gel route. The as-prepared carbon-coated NVP nanoparticles exhibiting an average size of approximately 200 nm were uniformly immobilized on a sodium polyacrylate (PAA) matrix, which effectively increases the specific surface area while maintaining the inherent NASICON crystal framework. Such a hierarchical configuration efficiently suppresses particle coarsening and aggregation, thereby promoting sodium-ion transport kinetics and improving electrochemical behavior. The resulting NVP/CP cathode delivers outstanding sodium storage performance, exhibiting a high operating voltage (3.32 V) and a high repeatable recovery capacitance performance of 101.52 mAh g–1 at 0.5 C. Even more unexpectedly, at a current density of 5C, the retention rate of its capacitance can still reach 87.6% after 5000 cycles, demonstrating excellent long-term cycling stability.