Zhao Hongyuan, Nie Yongfang, Que Dongyang, Hu Youzuo, Li Yongfeng
School of Mechanical and Electrical Engineering, Henan Institute of Science and Technology, Xinxiang 453003, China.
Zhumadian Power Supply Company, State Grid Henan Electric Power Company, Zhumadian 463500, China.
Materials (Basel). 2019 Aug 31;12(17):2807. doi: 10.3390/ma12172807.
In this work, the spinel LiMnO cathode material was prepared by high-temperature solid-phase method and further optimized by co-modification strategy based on the Mg-doping and octahedral morphology. The octahedral LiMnMgO sample belongs to the spinel cubic structure with the space group of Fd3m, and no other impurities are presented in the XRD patterns. The octahedral LiMnMgO particles show narrow size distribution with regular morphology. When used as cathode material, the obtained LiMnMgO octahedra shows excellent electrochemical properties. This material can exhibit high capacity retention of 96.8% with 100th discharge capacity of 111.6 mAh g at 1.0 C. Moreover, the rate performance and high-temperature cycling stability of LiMnO are effectively improved by the co-modification strategy based on Mg-doping and octahedral morphology. These results are mostly given to the fact that the addition of magnesium ions can suppress the Jahn-Teller effect and the octahedral morphology contributes to the Mn dissolution, which can improve the structural stability of LiMnO.
在本工作中，采用高温固相法制备了尖晶石LiMnO正极材料，并基于Mg掺杂和八面体形貌的共改性策略对其进行了进一步优化。八面体LiMnMgO样品属于空间群为Fd3m的尖晶石立方结构，XRD图谱中未出现其他杂质。八面体LiMnMgO颗粒尺寸分布窄，形貌规则。当用作正极材料时，所制备的LiMnMgO八面体表现出优异的电化学性能。该材料在1.0 C下第100次放电容量为111.6 mAh g时，可展现出96.8%的高容量保持率。此外，基于Mg掺杂和八面体形貌的共改性策略有效地提高了LiMnO的倍率性能和高温循环稳定性。这些结果主要归因于镁离子的加入可抑制 Jahn-Teller 效应，且八面体形貌有助于Mn的溶解，从而可提高LiMnO的结构稳定性。
