Abstract The different amounts of Mo6+ and the 2 wt% ZrF4 coating layer have been co-modified the Li[Li0.20Mn0.54Ni0.13Co0.13]O2 cathode material via using the carbonate co-precipitation method and wet coating process. And the influences of Mo6+ doping and ZrF4 surface coating on the cathode crystal structure, morphology and electrochemical properties were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), Transmission Electron Microscope (TEM) and galvanostatic charge–discharge tests. The 2 wt% ZrF4 coated-Li[Li0.20Mn0.52Ni0.13Co0.13Mo0.02]O2 demonstrated the lower cation mixing and a thickness of 15–35 nm film coated on the surface of cathode particles. Compared with the pristine cathode, the samples after ZrF4 coating and Mo6+ doping exhibited the less irreversible capacity loss, better high rate capability and superior cyclic performance owing to the lower impedance for Li+ migration across the SEI film and the faster Li+ migration speed in the cathode bulk. Among all samples, the 2 wt% ZrF4 coated-Li[Li0.20Mn0.52Ni0.13Co0.13Mo0.02]O2 showed the optimum electrochemical properties, with a high capacity retention of 88.7% after 100 cycles at 55 °C, much higher than that (82.9%) of the pristine cathode. Besides, when the electric current increased to 5C high rate, the pristine Li[Li0.20Mn0.54Ni0.13Co0.13]O2 delivered a discharge capacity of 21.9 mAh g−1 lower than that of 2 wt% ZrF4 coated-Li[Li0.20Mn0.52Ni0.13Co0.13Mo0.02]O2.

中文翻译：

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Mo掺杂改善ZrF 4 包覆Li[Li 0.20 Mn 0.54 Ni 0.13 Co 0.13 ]O 2 作为锂离子电池高性能正极材料

摘要 通过碳酸盐共沉淀法和湿法包覆工艺，不同量的Mo6+和2wt%的ZrF4涂层共改性Li[Li0.20Mn0.54Ni0.13Co0.13]O2正极材料。并通过X射线衍射（XRD）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）和恒电流充放电测试研究了Mo6+掺杂和ZrF4表面涂层对阴极晶体结构、形貌和电化学性能的影响. 2 wt% ZrF4 涂层-Li[Li0.20Mn0.52Ni0.13Co0.13Mo0.02]O2 表现出较低的阳离子混合和涂覆在阴极颗粒表面上的 15-35 nm 膜厚。与原始正极相比，ZrF4 涂层和 Mo6+ 掺杂后的样品表现出较小的不可逆容量损失，由于跨 SEI 膜的 Li+ 迁移阻抗较低且正极体中的 Li+ 迁移速度更快，因此具有更好的高倍率能力和优异的循环性能。在所有样品中，2 wt% ZrF4 包覆的-Li[Li0.20Mn0.52Ni0.13Co0.13Mo0.02]O2 表现出最佳的电化学性能，在 55°C 下循环 100 次后容量保持率高达 88.7%，远高于比原始阴极 (82.9%) 高。此外，当电流增加到 5C 高倍率时，原始 Li[Li0.20Mn0.54Ni0.13Co0.13]O2 的放电容量比 2 wt% ZrF4 包覆的 Li[Li0 .20Mn0.52Ni0.13Co0.13Mo0.02]O2。52Ni0.13Co0.13Mo0.02]O2 显示出最佳的电化学性能，在 55°C 下循环 100 次后容量保持率为 88.7%，远高于原始正极的容量保持率 (82.9%)。此外，当电流增加到 5C 高倍率时，原始 Li[Li0.20Mn0.54Ni0.13Co0.13]O2 的放电容量比 2 wt% ZrF4 包覆的 Li[Li0 .20Mn0.52Ni0.13Co0.13Mo0.02]O2。52Ni0.13Co0.13Mo0.02]O2 显示出最佳的电化学性能，在 55°C 下循环 100 次后容量保持率为 88.7%，远高于原始正极的容量保持率 (82.9%)。此外，当电流增加到 5C 高倍率时，原始 Li[Li0.20Mn0.54Ni0.13Co0.13]O2 的放电容量比 2 wt% ZrF4 包覆的 Li[Li0 .20Mn0.52Ni0.13Co0.13Mo0.02]O2。