Improving Electrochemical Performance of The Layer-Structured Ncm Cathode Materials For Large-Scale Lithium Ion Batteries

Ni-rich layered LiNi x Co y Mn(1- x - y )O 2 (x≥0.8) has been considered as promising candidate cathodes due to their large specific capacity, high rate capability and low cost. However, Ni-rich materials suffer from severe capacity fading, especially, when cycled at high temperatures due to the formation of highly reactive Ni 4+ at charge state. Ni 4+ has strong oxidizing property and the reaction between Ni 4+ and the electrolyte will be accompanied by gas evolution, which causes severe swelling of the cell. Moreover, the formation LiOH and Li 2 CO 3 on the surface is prone because of residual lithium on the surface, which is remained dut to an excess of lithium to creat a well ordered layered phase. The reaction with electroytes negatively impact the cycling performance by decomposing electrolytes. Therefore, it is necessary to improve the structure and interfacial stability, and many studies have indicated coating and doping approach. The coating for NCM materials is often used with stable metal oxides such as ZrO 2 , Al 2 O 3 , TiO 2 , SiO 2 and Li 2 ZrO, and the commonly used dopant elements are Al, Mg, Ti, Zr and Fe. In this work, TiO 2 coated and Ti doped LiNi 0.8 Co 0.1 Mn 0.1 O 2 were synthesized at the same time to improve the structure stability and suppress the side reaction with electrolytes. TiO 2 nano-powder as a raw material was used to coating and doping through a convenient solid state synthesis process. As a result, the electrochemical performance of LiNi 0.8 Co 0.1 Mn 0.1 O 2 cathode was enhanced.