Abstract:

Sodium vanadium phosphate (Na₃V₂(PO₄)₃, abbreviated as NVP）, exhibits unique advantages in sodium?ion batteries due to its excellent thermal stability and broad sodium?ion transport channels. However, the expensive vanadium raw materials have diminished the attention on the commercial development of NVP. In this work, NVP was successfully synthesized using solid?state methods from NaVO₃, a byproduct from the upstream of the vanadium extraction industry, and compared with NVP synthesized from V₂O₅ and NH₄VO₃ at different calcination temperatures. The results indicate that the vanadium source has a significant impact on the structure and morphology of NVP, which further influences the battery capacity and rate performance. NVP prepared using NaVO₃ at 750 ℃ exhibits excellent electrochemical performance, achieving an initial high capacity of 105.6 mA·h/g at 0.1 C, and still obtaining high capacities of 101.5, 99.9, and 92.9 mA·h/g at subsequent rates of 1.0, 2.0, and 5.0 C, respectively. Moreover, it achieves a reversible capacity of 97.1 mA·h/g and a high capacity retention rate of 94.6% after 300 cycles at 1.0 C, and retains 94.0% capacity after 500 cycles at 5.0 C. This simple, efficient, and cost?effective synthesis strategy provides a reference for the scaled?up production of NVP.

Key words: Sodium?ion batteries, Cathode material, Na₃V₂(PO₄)₃, NaVO₃, Solid?phase method

摘要：

磷酸钒钠（Na₃V₂(PO₄)₃，简称NVP）由于其较强的热稳定性和宽阔的钠离子传输通道,在钠离子电池的应用中具有独特优势。然而，价格昂贵的钒原料减弱了NVP在商业化发展中的关注度。以提钒工业上游产物NaVO₃为钒源,利用固相法成功合成了NVP，并将其与以V₂O₅和NH₄VO₃为钒源、在不同煅烧温度下合成的NVP进行对比。结果表明，钒源对NVP的结构和形貌具有重要影响，并进一步影响电池的比容量和倍率性能；以NaVO₃为钒源、在750 ℃合成的NVP展现出优异的电化学性能，在0.1 C下获得了较高的初始比容量（105.6 mA·h/g），并且在1.0、2.0、5.0 C下仍能保持101.5、99.9、92.9 mA·h/g的高比容量；在1.0 C下循环300圈后，可逆比容量达97.1 mA·h/g，容量保持率高达94.6%，在5.0 C下循环500圈后容量保持率仍达94.0%。这种基于简单高效且使用廉价原料的合成策略对NVP的规模化生产具有借鉴意义。

关键词: 钠离子电池, 正极材料, 磷酸钒钠, 偏钒酸钠, 固相法