Powder electrochemical properties with different particle sizes of spinel LiAl0.05Mn1.95O4 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 (LiAl0.05Mn1.95O4) with different particle sizes were obtained through ball milling. The effects of particle size on the electrochemical performance of LiAl0.05Mn1.95O4 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; LiAl0.05Mn1.95O4 with D50 = 17.3 μm shows better capacity retention: LiAl0.05Mn1.95O4 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.