Oxygen redox chemistry in lithium-rich cathode materials for Li-ion batteries: Understanding from atomic structure to nano-engineering

Lithium-rich oxide compounds have been recognized as promising cathode materials for high performance Li-ion batteries, owing to their high specific capacity. However, it remains a great challenge to achieve the fully reversible anionic redox reactions to realize high capacity, high stability, and low voltage hysteresis for lithium-rich cathode materials. Therefore, it is critically important to comprehensively understand and control the anionic redox chemistry of lithium-rich cathode materials, including atomic structure design, and nano-scale materials engineering technologies. Herein, we summarize the recent research progress of lithium-rich cathode materials with a focus on redox chemistry. Particularly, we highlight the oxygen-based redox reactions in lithium-rich metal oxides, with critical views of designing next generation oxygen redox lithium cathode materials. Furthermore, we purposed the most promising strategies for improving the performances of lithium-rich cathode materials with a technology-spectrum from the atomic scale to nano-scale.