Study of the properties of LiAlO2-coated spinel LiMn2O4 prepared by a one-step liquid-phase method

Abstract

The LiMn2O4@xLiALO2 (0, 0.5 %, 1 %, 2 %, 3 %) cathode material of LiMn2O4 coated with LiAlO2 was prepared by an optimized liquid phase coating process, namely one step liquid phase method, and its electrochemical properties were tested, characterized by SEM, TEM, EDS, XRD, etc. The results showed that: After coating, a layer of dense LiAlO2 coating is formed on the surface of the material, the shape of the material is like spherical particles, and the cyclic performance of the material is improved significantly at room temperature and high temperature. Among them, LMO@2 % sample at 25 °C 0.2 C(1 C=148 mA h/g) first discharge specific capacity is 110.29 mA h/g, 1 C cycle 100 weeks discharge specific capacity is 99.4 mA h/g, the 1 C cycle retention rate is 95 %; At 55 °C, the initial discharge specific capacity of 0.2 C was 111.48 mA h/g, the discharge specific capacity of 1 C cycle 100 weeks was 90.23 mA h/g, and the cycle retention rate of 1 C was 84 %, while the cycle retention rate of LMO samples for 100 weeks was only 72 %. CV and EIS tests show that coated LiAlO2 can effectively inhibit electrode polarization and increase the diffusion rate of Li+.