Accelerating Na ⁺ Diffusion Kinetics of Na ₃ V ₂ (PO ₄ ) ₃ Cathode for High-Performance Sodium-Ion Batteries via In Situ Configured Cross-Linked Carbon Networks

Na₃V₂(PO₄)₃ has garnered significant attention as a promising cathode material for sodium-ion batteries due to its excellent ionic conductivity and robust structural stability. However, its further large-scale practical application has been hindered by its low electrical conductivity and poor interface kinetics. Therefore, it is reported in this study that the discharging/charging cycling and rate performance of Na₃V₂(PO₄)₃ cathodes are dramatically improved by the uniformly formed 3D carbon networks. Evidently, the Na₃V₂(PO₄)₃ cathode material prepared under the optimized conditions exhibited a relatively high initial capacity of 109.30 mAh/g at 0.1C with an initial Coulombic efficiency (ICE) of 99% and achieved an appreciable capacity of 99.42 mAh/g with a capacity retention of 96.39% after 400 cycles at 2C. Based on different characterizations and electrochemical performances, both the formation and sodium storage mechanism of Na₃V₂(PO₄)₃-based composite cathodes were initially concluded, which is significant and important for improving electrical conductivity and designing practical carbon-cladding strategies for Na-ion batteries.