Improved electrochemical performance of magnesium-doped LiNi0.8-xMgxCo0.1Mn0.1O2 by CTAB-assisted solvothermal and calcining method

As high nickel ternary material is becoming more superior to other positive electrode material for its high-specific capacity and the characteristics of low cost, it has been widely researched recently, especially for the LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode material used in lithium-ion batteries, which lowers metal cobalt content in the precursors, thus greatly reduce the cost of the raw material. However, it is well known that with the increase of nickel, the Li/Ni mixing phenomenon becoming more and more obvious, leading to the NCM811 did very badly on electrochemical performance, especially for the cycle performance. In this paper, Mg-doped LiNi0.8-x MgxCo0.1Mn0.1O2 (x = 0, 0.01, 0.03, 0.05) material with good crystallinity and uniformed particles is synthesized by solvothermal and calcining method. The cation mixing effect was inhibited by a fact that the ionic radius of Mg2+ is closer to that of Ni2+ than that of Li+. Results showed that the first discharge specific capacity of doped material is 218 mAh center dot g(-1) at the current of 18 mA/g(0.1 C), and the capacity retention is 87.3% after 100 cycles, which are improved at 38 mAh center dot g(-1) and 12.3%, respectively, compared with pristine material. We attributed this improvement mechanism to the improvement of the order of layered structure in NCM811 by Mg doping, which provide the improvement of the structure in crystal dynamics.

Automated summary

This study synthesized Mg-doped LiNi0.8-xMgxCo0.1Mn0.1O2 material using solvothermal and calcining method. By inhibiting cation mixing effect, the performance of the material was improved.