Rapid thermal annealing-enabled fabrication of high-performance NASICON-Type Na3V2(PO4)3 thin films for sodium-ion batteries

The rapid advancement of wearable electronics and miniaturized medical devices demands high-safety, low-cost energy storage. Sodium-ion batteries (SIBs) attract attention for their resource advantages and lithium-ion battery-like electrochemical mechanisms, but their performance is limited by Na + ’s larger ionic radius—causing severe lattice stress and electrode degradation. This study focuses on NASICON-type Na 3 V 2 (PO 4 ) 3 (NVP) cathodes, developing an innovative sol–gel spin-coating method combined with rapid thermal annealing (RTA) to grow high-quality films on carbon-coated Ti substrates. Multi-scale characterization confirms the films have a typical NASICON structure, smooth surface, uniform element distribution, and stable vanadium valence. Electrochemically, the film electrode delivers an initial reversible capacity of 83mAh g −1 at 1 A g −1 (70.9 % of theoretical value) and retains 81.3 % capacity after 300 cycles. Cyclic voltammetry shows reversible redox peaks at 0.49/0.66 V, and electrochemical impedance spectroscopy gives a low ohmic resistance of 13.3 Ω. Notably, RTA enhances film crystallinity and densification while simplifying conventional 8–10 h multi-step sintering into a 1-h single step, offering an efficient, low-energy industrial solution for scalable all-solid-state SIB production.