Degradation mechanism of spinel LiAl0.2Mn1.8O4 cathode materials on high temperature cycling

The structural degradation of the Al-doped spinel material, LiAl0.2Mn1.8O4, before and after charge–discharge cycling in the 4 V region at elevated temperature has been studied by X-ray diffraction and high-resolution transmission electron microscopy. The capacity loss during cycling was noticeably increased with cell operation temperature from 50 to 80 °C. The formation of tetragonal Li2Mn2O4 and the rocksalt phase Li2MnO3 in the spinel electrode cycled at elevated temperature could be responsible for the main cause of the capacity loss.