X-ray absorption fine structure study on Li-Mn-O compounds: LiMn2O4, Li4Mn5O12 and Li2MnO3

The lithium manganese oxide spinel LiMn2O4 obtained at different preparation temperatures shows different discharge characteristics. In order to study the difference between the discharge curves of HT-LiMn2O4 (HT: high temperature) and LT-LiMn2O4 (LT: low temperature), we have analyzed the XAFS (X-ray absorption fine structure) of synthesized LiMn2O4 and the products formed from an electrochemical oxidation—reduction process. It was found that, on discharge, the energy shifts of the edge of the X-ray absorption near edge structure (XANES) spectra were different between HT-LiMn2O4 and LT-LiMn2O4 and were not directly proportional to the discharge capacity. Moreover, the change in the Mn-Mn bond length of HT-LiMn2O4 with discharge was greater than that of LT-Mn2O4.