A lithium-rich manganese-based cathode material, Li1.25Ni0.2Co0.333Fe0.133Mn0.333O2, was prepared using a polyvinyl alcohol (PVA)-auxiliary sol-gel process using MnO2 as a template. The effect of the PVA content (0.0–15.0 wt%) on the electrochemical properties and morphology of Li1.25Ni0.2Co0.333Fe0.133Mn0.333O2 was investigated. Analysis of Li1.25Ni0.2Co0.333Fe0.133Mn0.333O2 X-ray diffraction patterns by RIETAN-FP program confirmed the layered α-NaFeO2 structure. The discharge capacity and coulombic efficiency of Li1.25Ni0.2Co0.333Fe0.133Mn0.333O2 in the first cycle were improved with increasing PVA content. In particular, the best material reached a first discharge capacity of 206.0 mAhg−1 and best rate capability (74.8 mAhg−1 at 5 C). Meanwhile, the highest capacity retention was 87.7% for 50 cycles. Finally, electrochemical impedance spectroscopy shows that as the PVA content increases, the charge-transfer resistance decreases.

中文翻译：

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聚乙烯醇辅助溶胶-凝胶法合成锂离子电池Li1.25Ni0.2Co0.333Fe0.133Mn0.333O2正极材料的电化学性能改善

以MnO2为模板，采用聚乙烯醇（PVA）-辅助溶胶-凝胶法制备了富锂锰基正极材料Li1.25Ni0.2Co0.333Fe0.133Mn0.333O2。研究了 PVA 含量（0.0-15.0 wt%）对 Li1.25Ni0.2Co0.333Fe0.133Mn0.333O2 电化学性能和形貌的影响。通过 RIETAN-FP 程序对 Li1.25Ni0.2Co0.333Fe0.133Mn0.333O2 X 射线衍射图的分析证实了层状 α-NaFeO2 结构。Li1.25Ni0.2Co0.333Fe0.133Mn0.333O2在第一次循环中的放电容量和库仑效率随着PVA含量的增加而提高。特别是，最好的材料达到了 206.0 mAhg-1 的首次放电容量和最佳倍率性能（5 C 时为 74.8 mAhg-1）。同时，最高容量保持率为 87.7%，循环 50 次。最后，