High-Energy Cathode Materials Based on Anion Redox
Conventional intercalation cathodes predominantly rely on the redox of transition metal cations, which is typically limited to single-electron transfer processes that constrain their achievable capacity. A renowned example is the commercial NMC (LiNixMnyCozO2) cathodes in lithium-ion batteries, which are approaching their theoretical capacity limit.
Activating anionic redox chemistry in cathode frameworks enables multi-electron transfer reactions, offering a promising pathway to dramatically enhance charge storage capacity, and holding the potential to push the energy boundary of existing cathode materials. However, this process presents significant challenges: the evolving valence states of oxygen/sulfur during redox processes frequently induce local structure distortions, triggering lattice oxygen release through over-oxidation, and ultimately lead to irreversible cathode degradation and performance fading.
Our research systematically investigates the fundamental mechanisms of anionic redox and multi-electron transfer processes in layered cathode materials. Through strategic band structure engineering and design of protective surface coatings, we aim to achieve precise control over anionic redox activity. This approach enables us to develop novel cathode materials that combine high capacity with excellent structural stability, paving the way for next-generation high-energy battery systems.
