Improved Lithium Ion Diffusion and Stability of a LiNi <sub>0.8</sub> Co <sub>0.1</sub> Mn <sub>0.1</sub> O <sub>2</sub> Cathode via the Synergistic Effect of Na and Mg Dual-Metal Cations for Lithium Ion Battery
Sun Yanxia, Hai Chunxi, Shen Yue, Zeng Jinbo, Zhang Lijuan, Xiang Li, Xiufeng Ren, Dong Shengde, Zhang Guotai, Sun Chao, Yuan Zhou
Abstract
Nickel-rich ternary material LiNi 0.8 Co 0.1 Mn 0.1 O 2 is the promising cathode for lithium ion battery, but it has the disadvantage of structural instability. The common method for modifying its electrochemical performance is element doping, such as sodium, aluminum, magnesium and other elements, because the elements with different types and valences have varied ionic radii and binding energies to oxygen. They are incorporated into the layered nickel-rich ternary material to play the distinct roles. In this work, we investigate the effect of Na and Mg co-doping on Li(Ni 0.8 Co 0.1 Mn 0.1 )O 2 . Our results suggest that the mixed doping has no effect on the crystal structure and morphology of the material. The Rietveld refinement results demonstrated that cation mixing reduced. The electrochemical test results show that the proper amount of Na and Mg mixed doping improves the cyclic reversibility and reduces the resistance of the material. Na and Mg elements can promote each other to improve the electrochemical performance of the material. At the same time we note that high doping concentrations might mitigate the Li diffusion rates.