Effect of the elevated temperature on the local structure of lithium manganese oxide studied by in situ XAFS analysis

Effect of the elevated temperature and that of the lithium deintercalation on the structure of stoichiometric material LiMn2O4 and lithium excess material Li(Mn1.85Li0.15)O4 were investigated by in situ XAFS technique. The stoichiometric material showed capacity loss after charge–discharge cycles at 60°C and gave deformed XAFS spectra, while the lithium excess material showed resistance to the high-temperature cycling and gave a similar XAFS spectra to the non-heated material. The XAFS analysis suggests that high-temperature cycles caused structural disorder of LiMn2O4, but not that of Li(Mn1.85Li0.15)O4. Since the lithium excess material has good structural stability against the cycling at the elevated temperature, this material will be suitable for the cathode material of the commercial batteries.