Electrospun NaVPO₄F/C Nanofibers as Self-Standing Cathode Material for Ultralong Cycle Life Na-Ion Batteries

NaVPO₄F has received a great deal of attention as cathode material for Na-ion batteries due to its high theoretical capacity (143 mA h g⁻¹), high voltage platform, and structural stability. Novel NaVPO₄F/C nanofibers are successfully prepared via a feasible electrospinning method and subsequent heat treatment as self-standing cathode for Na-ion batteries. Based on the morphological and microstructural characterization, it can be seen that the NaVPO₄F/C nanofibers are smooth and continuous with NaVPO₄F nanoparticles (≈6 nm) embedded in porous carbon matrix. For Na-storage, this electrode exhibits extraordinary electrochemical performance: a high capacity (126.3 mA h g⁻¹ at 1 C), a superior rate capability (61.2 mA h g⁻¹ at 50 C), and ultralong cyclability (96.5% capacity retention after 1000 cycles at 2 C). 1D NaVPO₄F/C nanofibers that interlink into 3D conductive network improve the conductivity of NaVPO₄F, and effectively restrain the aggregation of NaVPO₄F particles during charge/discharge process, leading to the high performance.