Mo-doping for improving the ZrF4 coated-Li[Li0.20Mn0.54Ni0.13Co0.13]O2 as high performance cathode materials in lithium-ion batteries
Mo-doping for improving the ZrF4 coated-Li[Li0.20Mn0.54Ni0.13Co0.13]O2 as high performance cathode materials in lithium-ion batteries
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DOI：
10.1016/j.jallcom.2018.07.068
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发表时间：
2018-10
影响因子：
6.2
通讯作者：
Yi Lu;Shiliang Shi;Fan Yang;Zhang Tianyu;Hui-yong Niu;Tao Wang
中科院分区：
文献类型：
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作者：
Yi Lu;Shiliang Shi;Fan Yang;Zhang Tianyu;Hui-yong Niu;Tao Wang
采用碳酸盐共沉淀法和湿法包覆工艺对Li[Li0.20Mn0.54Ni0.13Co0.13]O2正极材料进行了不同含量的Mo6+和2 wt%ZrF4包覆层的共修饰。并通过X射线衍射仪、扫描电子显微镜、透射电子显微镜和恒流充放电测试研究了Mo6+掺杂和表面涂层对正极晶体结构、形貌和电化学性能的影响。ZrF4coated-Li[Li0.20Mn0.52Ni0.13Co0.13Mo0.02]O2demonstrated含量为2 wt%时，阳离子混合程度较低，在阴极颗粒表面包覆了15~35 nm的薄膜。与未涂覆的正极相比，包覆和掺杂Mo6+的样品具有较小的不可逆容量损失、较好的高倍率性能和更好的循环性能，这是由于Li+在SEI膜上的迁移阻抗较低以及正极体内Li+的迁移速度较快所致。其中，ZrF4coated-Li[Li0.20Mn0.52Ni0.13Co0.13Mo0.02]O2showed质量分数为2 的正极材料的电化学性能最好，在55 °C循环100次后的容量保持率为88.7%，远高于原始正极材料的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%−低21.9mAhg
The different amounts of Mo6+and the 2 wt% ZrF4coating layer have been co-modified the Li[Li0.20Mn0.54Ni0.13Co0.13]O2cathode material via using the carbonate co-precipitation method and wet coating process. And the influences of Mo6+doping and ZrF4surface 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% ZrF4coated-Li[Li0.20Mn0.52Ni0.13Co0.13Mo0.02]O2demonstrated 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 ZrF4coating 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% ZrF4coated-Li[Li0.20Mn0.52Ni0.13Co0.13Mo0.02]O2showed 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]O2delivered a discharge capacity of 21.9 mAh g−1lower than that of 2 wt% ZrF4coated-Li[Li0.20Mn0.52Ni0.13Co0.13Mo0.02]O2.