Understanding anionic redox chemistry from the perspective of electronic structure

Abstract

The rapidly growing electric cars and energy storage systems have extremely promoted the development of advanced lithium and sodium ion batteries and stimulated evolution of high-capacity cathodes. Li/Na-rich layered cathodes consisting cationic and anionic reactions as the most typical representative of high-capacity cathodes have shown its tremendous potential. However, there is a long way to go before commercialization because of unsatisfactory performances including large voltage hysteresis, voltage fade and poor cycle performance. Numerous investigations on redox mechanisms and engineering strategies have been performed from the point view of structure and made significant progress, which has been well reviewed. Meanwhile, the unacceptable issues are essentially correlated to the electronic configuration of anionic redox and its interaction with adjacent transition metal cations, which can be well depicted from electronic structure. However, the investigations on anionic reaction process in the viewpoint of electronic structure have been much less summarized. This review aims to compile the current knowledge of anionic redox from the point view of electronic structure, including configuration, origination, evolution, detection and coupling relationship with cationic redox. This work is attempted to inspire new perspectives and design approaches for the development of high-capacity cathodes.

Graphical Abstract