Doping Mg2+ to improve the Li+ diffusion rate and electrochemical performance of spinel LiMn2O4

In order to improve the normal temperature and high temperature cycling performance of spinel LiMn2O4, Mg2+-doped LiMn2-xMgxO4(0 ≤ x ≤ 0.1) cathode material was synthesized by the liquid phase method. XRD and EDS tests show that the doped Mg2+ successfully replaced part of Mn3+ into the lithium manganate cathode material lattice. After doping, the crystal structure is a spinel structure without impurity phase. Electrochemical performance tests show that different Mg2+ doping amount can effectively inhibit LiMn2O4 capacity attenuation during charging and discharging. The specific capacity of LiMn1.95Mg0.05O4 is 111.9 mAh/g at the current density of 0.2C at room temperature for the first discharge, the first discharge specific capacity of 1C was 110.06 mAh/g, and the discharge specific capacity was 105.79 mAh/g after 100 cycles, and the capacity retention rate is 96.12%. The specific capacity of the first discharge at a 0.2C current density at high temperature was 113.4 mAh/g, and after 100 cycles at 1C current density, the specific capacity is 99.29 mAh/g, and the capacity retention rate is 89.32%. The normal temperature and high temperature cycle performance of the sample is higher than that of the undoped Mg2+ sample.