Recent advance in Mn-based Li-rich cathode materials: Oxygen release mechanism and its solution strategies based on electronic structure perspective, spanning from commercial liquid batteries to all-solid-state batteries

The current widespread use of lithium-ion batteries (LIBs) in transportation and consumer electronics has spurred the pursuit of developing cathode materials with enhanced energy density, aiming to commercialize LIBs with improved performance. Mn-based Li-rich layered oxides, among the various types of cathode materials, possess outstanding merits such as high energy density, low cost, and environmentally friendly, which make them the most promising commercial cathode materials for LIBs. However, the low initial cycle efficiency, voltage and capacity attenuation, and phase transformation significantly slow down the process of commercial application. The essential origin of the above drawbacks is the redox reaction from the lattice oxygen in the initial uptake/release process. Based on the advanced characterizations and theoretical analysis, researchers have gained a deep understanding of the fundamental issues and subsequent solution strategies. Firstly, this present article provides a comprehensive review of the redox reaction mechanism involving lattice oxygen in liquid lithium-ion battery avenue, focusing on the perspective of electronic energy levels. Then, the article provides an in-depth analysis and summary of the relevant solution strategies, as well as a detailed overview of the application and challenges of Li-rich cathode materials in all-solid-state lithium-ion batteries (ASSLBs). The primary objective of this review is to offer targeted guidance for the development of Li-rich cathodes that are both highly efficient and safe, with a particular emphasis on their potential application in the future all-solid-state battery technology. • The redox reaction mechanism of lattice oxygen is summarized from the perspective of electronic energy levels. • The strategies for alleviating lattice oxygen loss are summarized. • The failure mechanism and future development direction of LLMO in ASSLB are analyzed and discussed.