Improved Electrochemical Properties of LiMn₂O₄-Based Cathode Material Co-Modified by Mg-Doping and Octahedral...

In this work, the spinel LiMn₂O₄ cathode material was prepared by high-temperature solid-phase method and further optimized by co-modification strategy based on the Mg-doping and octahedral morphology. The octahedral LiMn_1.95Mg_0.05O₄ sample belongs to the spinel cubic structure with the space group of Fd3m, and no other impurities are presented in the XRD patterns. The octahedral LiMn_1.95Mg_0.05O₄ particles show narrow size distribution with regular morphology. When used as cathode material, the obtained LiMn_1.95Mg_0.05O₄ octahedra shows excellent electrochemical properties. This material can exhibit high capacity retention of 96.8% with 100th discharge capacity of 111.6 mAh g^-1 at 1.0 C. Moreover, the rate performance and high-temperature cycling stability of LiMn₂O₄ are effectively improved by the co-modification strategy based on Mg-doping and octahedral morphology. These results are mostly given to the fact that the addition of magnesium ions can suppress the Jahn-Teller effect and the octahedral morphology contributes to the Mn dissolution, which can improve the structural stability of LiMn₂O₄.