Preparing LiNixCoyMn1-x-yO2 via hydrothermal precipitation

• 1、Chongqing Vehicle Test & Research Institute, Chongqing 401122, China

Abstract：Using urea as precipitating agent, three cathode materials LiNi1/3Co1/3Mn1/3O2, LiNi0.5Co0.2Mn0.3O2 and LiNi0.8Co0.1Mn0.1O2 were synthesized by hydrothermal precipitation method. According to the XRD spectrum, the cation mixing phenomenon appeared in the materials with high Ni content. The SEM diagramshowed that the LiNi0.5Co0.2Mn0.3O2 Preparing LiNixCoyMn1-x-yO2 via hydrothermal precipitationsample has obvious core-shell structure, which is caused by the different solubility product of metal ions. The increase of Ni content can improve the capacity of cathode materials.However, Ni2+ is difficult to be completely oxidized to Ni3+ during the calcination process,and the presence of Ni2+ aggravates the cation mixing phenomenon, which seriously affects the reversible capacity, cycle performance and rate performance of the material. Therefore, the LiNi0.5Co0.2Mn0.3O2 sample showed the highest initial discharge specific capacity of 166.7mAh/g, while the LiNi1/3Co1/3Mn1/3O2 sample has the best cycle performance and rate performance. The sample of LiNi1/3Co1/3Mn1/3O2delivered a discharge specific capacity of 85.6 mAh/g at 2 C rate. The discharge specific capacity was 106.0 mAh/g after 50 cycles at 0.5 C rate, and the capacity retention rate was 83.0 %.

Keywords： Li-ion battery；cathode material；hydrothermal precipitation method