Ce-doped Na3V1.9Ce0.1(PO4)2F3 as a cathode material for high-performance sodium-ion batteries†

Abstract

The sodium-based polyanionic cathode material Na₃V₂(PO₄)₂F₃ has emerged as a promising candidate due to its exceptional energy density and robust structural stability. In this study, an innovative synthesis strategy integrating freeze-drying with microwave sintering was employed to fabricate the Na₃V₂(PO₄)₂F₃ cathode material. Furthermore, Ce³⁺ doping was strategically incorporated to optimize the material's electrochemical performance. The structural and morphological characteristics of the synthesized material were systematically investigated through X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy. The electrochemical performance of the material was evaluated via galvanostatic charge–discharge measurement. The research findings reveal that the NVPF-Ce0.1 sample exhibits superior particle size uniformity compared to NVPF. Electrochemical characterization reveals that the NVPF-Ce0.1 sample exhibits a low charge transfer resistance of 125.6 Ω and delivers an initial discharge capacity of 113.68 mA h g⁻¹. Remarkably, NVPF-Ce0.1 retains 98.8 mA h g⁻¹ after 100 cycles at 1C rate, outperforming all comparable samples in our study. Further electrochemical analysis reveals that NVPF-Ce0.1 exhibits a reduced peak potential compared to pristine NVPF, indicating significantly decreased polarization and improved reaction kinetics.