Electrochemical Property of Li-Mn Cation Disordered Li-Rich Li2MnO3with NaCl Type Structure

A cation disordered Li2MnO3 with NaCl type structure is found to show good electrochemical performance. The initial charge profile of the disordered Li2MnO3 shows a plateau at 4.1 V, while the ordered Li2MnO3 shows a plateau at 4.4 V. The good electrochemical activity affects the subsequent electrochemical performance, i.e., its initial charge and discharge capacities are 410 mA h g− 1 and 320 mA h g− 1. An iodometry and an X-ray fluorescence reveals that Mn ion in Li2MnO3 reduces from 4+ to ca. 3.7+ accompanying some amount of O2 release from Li2MnO3, during the disordering process. Such oxygen deficiency might be one of the key factors that improves the initial electrochemical activity of the Li2MnO3(4+). Ex-situ XRD reveals that the lattice size of the disordered Li2MnO3 changes by about 3% during cycling.