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

Tuesday, 15 May 2018
Ballroom 6ABC (Washington State Convention Center)
H. S. Kim (KERI), S. Sim (Korea Electrotechnology Research Institute), and B. S. Jin (KERI)
Ni-rich layered LiNixCoyMn(1-x-y)O2 (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 Ni4+ at charge state. Ni4+ has strong oxidizing property and the reaction between Ni4+ and the electrolyte will be accompanied by gas evolution, which causes severe swelling of the cell. Moreover, the formation LiOH and Li2CO3 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 ZrO2, Al2O3, TiO2, SiO2 and Li2ZrO, and the commonly used dopant elements are Al, Mg, Ti, Zr and Fe.

In this work, TiO2 coated and Ti doped LiNi0.8Co0.1Mn0.1O2 were synthesized at the same time to improve the structure stability and suppress the side reaction with electrolytes. TiO2 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 LiNi0.8Co0.1Mn0.1O2 cathode was enhanced.