Xu Wangqiong, Zheng Yonghui, Cheng Yan, Qi Ruijuan, Peng Hui, Lin Hechun, Huang Rong
Key Laboratory of Polar Materials and Devices (MOE) and Department of Electronics Sciences, School of Physics and Electronic Science, East China Normal University, Shanghai 200062, China.
Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China.
ACS Appl Mater Interfaces. 2021 Sep 29;13(38):45446-45454. doi: 10.1021/acsami.1c11315. Epub 2021 Sep 17.
It is well known that the electrochemical performance of spinel LiMnO can be improved by Al doping. Herein, combining X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, and spherical aberration-corrected scanning transmission electron microscopy (Cs-STEM) with electron-beam (E-beam) irradiation techniques, the influence of Al doping on the structural evolution and stability improvement of the LiMnO cathode material is revealed. It is revealed that an appropriate concentration of Al ions could dope into the spinel structure to form a more stable LiAlMnO phase framework, which can effectively stabilize the surface and bulk structure by inhibiting the dissolution of Mn ions during cycling. The optimized LiAlMnO sample exhibits a superior capacity retention ratio of 80% after 1000 cycles at 10 C (1 C = 148 mA h g) in the voltage range of 3.0-4.5 V, which possesses an initial discharge capacity of 90.3 mA h g. Compared with the undoped LiMnO sample, the Al-doped sample also shows superior rate performance, especially the capacity recovery performance.
众所周知，通过铝掺杂可以提高尖晶石LiMnO的电化学性能。在此，将X射线衍射、拉曼光谱、X射线光电子能谱以及球差校正扫描透射电子显微镜（Cs-STEM）与电子束（E-beam）辐照技术相结合，揭示了铝掺杂对LiMnO正极材料结构演变和稳定性提高的影响。结果表明，适当浓度的铝离子可以掺入尖晶石结构中，形成更稳定的LiAlMnO相框架，通过抑制循环过程中锰离子的溶解，能有效稳定表面和体相结构。优化后的LiAlMnO样品在3.0-4.5 V电压范围内，于10 C（1 C = 148 mA h g）下循环1000次后，展现出80%的优异容量保持率，其初始放电容量为90.3 mA h g。与未掺杂的LiMnO样品相比，铝掺杂样品还表现出优异的倍率性能，尤其是容量恢复性能。
