Continuous activation of Li2MnO3 component upon cycling in Li1.167Ni0.233Co0.100Mn0.467Mo0.033O2 cathode material for lithium ion batteries

Li-rich layered cathode materials are very promising candidates for next generation high energy lithium ion batteries. One of the Li-rich layered cathode materials, Li1.167Ni0.233Co0.100Mn0.467Mo0.033O2 is prepared by a co-precipitation method. In this report, we focus on anomalous changes upon cycling in Li1.167Ni0.233Co0.100Mn0.467Mo0.033O2 cathode material in a voltage range of 2.0-4.55 V at room temperature. The structural transitions upon cycling are analyzed by ex situ X-ray diffraction. In addition, the changes in local structure during cycling are studied by X-ray absorption near edge structure. With differential capacity plots by controlling the cut-off voltage, the voltage decay during cycling is intensively studied. The continuous activation process of the residual Li2MnO3 component during cycling is correlated with voltage decay during cycling, and increasing capacity during the initial several cycles. Also, the electrochemical performance in Li1.167Ni0.233Co0.100Mn0.467Mo0.033O2 cathode material below 4.4 V is discussed. Furthermore, cycle performance is improved by reassembling Li1.167Ni0.233Co0.100Mn0.467Mo0.033O2 into another cell after washing.