Achieving excellent cycling stability in LiNi0.9Co0.05Mn0.05O2 by Mg2+ doping

Abstract

High-nickel layered oxide cathodes with a nickel content of >80% exhibits high capacity and low cost, showing a great potential for next-generation lithium-ion batteries (LIBs). However, high nickel content usually leads to the exacerbation of phenomena such as harmful phase transitions, micro-cracks, and cationic disordering in high-nickel cathode materials during the cycling process. In this work, the LiNi0.9Co0.05Mn0.05O2 (NCM)cathode material is modified by Mg2⁺ doping. The research results show that the incorporation of Mg2+ can enhance the order degree of the material and expand the interlayer spacing of the Li layer, which is beneficial to enhance the Li+ diffusion and Improved cycle performance. When the Mg2+ doping amount is 1%, at a current density of 0.1 C, the initial specific discharge capacity is 210.05 mAh g-1, and it is 187.60 mAh g-1 after 100 cycles. The capacity retention rate reaches 89.31%, which is higher than that of NCM (77.97%). At a current density of 1 C, the initial specific discharge capacity is 174.59 mAh g-1, and it is 157.51 mAh g-1 after 100 cycles. The capacity retention rate is 90.22%, which is higher than that of NCM (79.79%)