Effect of sodium source on electrochemical performance of Na₃V₂(PO₄)₃ cathode material

Na₃V₂(PO₄)₃ structure cathode material of sodium ion battery of NASICON was synthesized under different sodium source via sol-gel and high temperature sintering method. The morphology, crystal structure, electrochemical performance and electrochemical impendance spectroscopy for Na₃V₂(PO₄)₃ cathode material were characterized and tested by means of scanning electron microscopy (SEM), powder X-ray diffraction (XRD), galvanostatic charge-discharge tests and electrochemical workstation. The results show that Na₂CO₃ as a sodium source synthesized Na₃V₂(PO₄)₃ has batter particle size, morphology and structure integrity. The best electrochemical performance and the smallest internal impedance are also obtained. The initial discharge specific capacity of the material is as high as 110.8 mAh/g at 0.2 C within the voltage range of 2.5~4.0 V, the capacity retention ratio is 85.1 % after 50 cycles.