Powder electrochemical properties with different particle sizes of spinel LiAl_0.05Mn_1.95O₄ synthesized by sol-gel method

An Al-doped spinel lithium manganese oxide was prepared by the adipic acid-assisted sol-gel method at 800°C, and the cathode materials (LiAl_0.05Mn_1.95O₄) with different particle sizes were obtained through ball milling. The effects of particle size on the electrochemical performance of LiAl_0.05Mn_1.95O₄ samples were investigated by differential thermal analysis and thermogravimetry, X-ray diffraction, galvanostatic charge-discharge test, cyclic voltammetry, and electrochemical impedance spectroscopy. The results indicate that all samples with different particle sizes show the same pure spinel phase and good crystal structure; LiAl_0.05Mn_1.95O₄ with D₅₀ = 17.3 μm shows better capacity retention: LiAl_0.05Mn_1.95O₄ cathode materials with small particle size have a bigger resistance of charge transfer than the large one, and the particle size has significant effects on the electrochemical performance of Al-doped spinel LiMn₂O₄ cathode materials.