Abstract The present study, report the sodium (Na) substituted lithium (Li) in LiMnPO4/C structure as an active material for lithium-ion batteries, and its effect on structure, morphology and electrochemical performances. Sodium with different concentrations has been substituted in the LiMnPO4 system using the solution combustion method. The XRD analysis confirmed a pure orthorhombic structure well indexed, which confirms a good substitution of Li+ ions by Na+. A maximum discharge capacity of 136.7 mAh g−1 was achieved for Li0.97Na0.03MnPO4/C composite cathode material compared to LiMnPO4/C (126.9 mAh g−1) with a coulombic efficiency of 93.8% higher than that of LiMnPO4/C (82.3%). It can be observed that the irreversible loss of capacity has been reduced by adding sodium (x = 0.03) Li0.97Na0.03MnPO4/C compared to LiMnPO4/C. With remarkable stability achieved, for the three doped samples (x = 0.01, 0.03 and 0.05 compared to x = 0.00), during the charge/discharge process.

中文翻译：

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Na取代LiMnPO4作为改进锂离子电池正极材料的合成与表征

摘要 本研究报告了LiMnPO4/C 结构中钠(Na) 取代锂(Li) 作为锂离子电池活性材料及其对结构、形貌和电化学性能的影响。使用溶液燃烧法在 LiMnPO4 系统中替代了不同浓度的钠。XRD 分析证实了纯斜方晶结构的良好索引，这证实了 Na+ 对 Li+ 离子的良好取代。与 LiMnPO4/C（126.9 mAh g-1）相比，Li0.97Na0.03MnPO4/C 复合正极材料的最大放电容量为 136.7 mAh g-1，库仑效率比 LiMnPO4/C 高 93.8%（ 82.3%）。可以观察到，与 LiMnPO4/C 相比，通过添加钠 (x = 0.03) Li0.97Na0.03MnPO4/C 减少了容量的不可逆损失。