Temperature dependence of the initial coulombic efficiency in Li-rich layered Li[Li0.144Ni0.136Co0.136Mn0.544]O2 oxide for lithium-ions batteries

In this study we report on the temperature dependence of the initial coulombic efficiency (ICE) in Li-rich layered Li[Li0.144Ni0.136Co0.136Mn0.544]O2 oxide, consisting of rhombohedral LiNi1/3Co1/3Mn1/3O2 and monoclinic Li2MnO3 component confirmed by SXRD and SAED. The electrochemical result shows that the ICE increases from 74.6 to 91.5% with the applied charging/discharging temperature from 0 to 50 °C, and it reproducibly approaches 92% when discharged at 50 °C, regardless of the applied charging temperature. From the dQ/dV plots, it is observed that the discharging temperature significantly influences the lithium intercalation into the MnO2-like component derived from Li2MnO3 component, i.e. the discharge process determines the ICE. This phenomenon indicates that the lithium re-intercalation into the MnO2-like component appears to be the most important factor.