Lithium-rich layered oxides are promising candidate cathode materials for the Li-ion batteries with energy densities above 300 Wh kg−1. However, issues such as the voltage hysteresis and decay hinder their commercial applications. Due to the entanglement of the transition metal (TM) migration and the anionic redox upon lithium extraction at high potentials, it is difficult to recognize the origin of these issues in conventional Li-rich layered oxides.