Interphase Engineering by Electrolyte Additives for Lithium-Rich Layered Oxides: Advances and Perspectives

Lithium-rich layered oxides (LLOs) are fascinating high-energy-density cathode materials for next-generation lithium-ion batteries (LIBs). However, the high voltage causes severe decomposition of conventional carbonate-based electrolytes at LLOs' surfaces, often producing a non-uniform, unstable, and non-protective cathode–electrolyte interphase (CEI), hindering the Li+ diffusion and reducing the electrochemical efficiency. Various side reactions, such as the release of lattice oxygen, dissolution of transition metals (especially manganese), and irreversible structural transformations, also occur and severely attenuate the electrochemical performance. Electrolyte additives provide a facile and effective approach to optimize the battery performance by in situ regulating the physical/chemical structures/properties of CEI. This paper reviews the research progress in functional electrolyte additives for LLOs and discusses the mechanisms of CEI construction with diverse functions. Finally, we tentatively propose suggestions to construct CEI by screening and customizing electrolyte additives to promote the large-scale application of LLOs for LIBs.