Insights into solvent molecule design for advanced electrolytes in lithium metal batteries

Abstract

Lithium metal batteries have attracted significant attention due to their promising high energy density. However, inherent limitations of lithium metal anodes, such as high reactivity, lithium dendrite growth, and the formation of “dead Li”, restrict their practical application. Electrolyte engineering can significantly enhance the performance of lithium metal batteries by optimizing the solvation structure, wherein the solvent molecules play a crucial role in determining the intrinsic physicochemical properties of the electrolytes. Through rational molecular structure optimization, the performance of the electrolyte can be intrinsically enhanced, and its formulation can be substantially improved. Herein, a comprehensive and in-depth summarization of recent advances in the design of electrolyte solvents for lithium metal batteries is presented, along with a critical evaluation of the strengths and limitations of various solvent molecules, including esters, ethers, and other solvent molecules containing heteroatoms. Additionally, an overview of fundamental molecular design principles has been distilled to effectively guide the exploitation of new solvents.