Facile synthesis of pure Na3V2(PO4)3 powder via a two-stage carbothermal reduction strategy

Sodium super ion conductor (NASICON) structure materials, known for fast diffusion channels for Na + , are promising solid electrolyte materials for sodium-ion batteries (SIBs). However, the high carbon content in the NASICON electrolyte materials originated from the carbothermal reduction (CR) reaction will cause short-circuit and self-discharge of the batteries. Herein, we developed a facile and straightforward two-stage calcining strategy to prepare Na 3 V 2 (PO 4 ) 3 (NVP) with high purity and crystallinity. By precisely controlling the dosage of reducing agent and heat temperature, the purity of NVP can reach 99.97%. Moreover, the NVP film was prepared by the as-synthesized pure NVP powder via fast hot-pressing sinter, whose Vickers hardness is (5.0 ± 0.4) × 10 2 HV and relative density is 99.05%. This study provides a safe and facile strategy to prepare high-purity NVP powder and high-quality NVP films, which is of great significance in exploring NVP as a solid electrolyte for SIBs. Graphical abstract