Enhancing Lithium-Ion-Battery Reliability through Weakly Solvating Molecule-Modified Carbonate Electrolytes

Abstract

Ester-based electrolytes, characterized by their high dielectric constant and low viscosity, have become the dominant commercial choice for lithium-ion batteries (LIBs). However, conventional solvents such as ethylene carbonate (EC) and dimethyl carbonate (DMC) exhibit strong coordination with Li⁺ ions, leading to high desolvation energy barriers that limit the battery performance. In this study, we propose a modified electrolyte system based on commercial ester electrolytes by introducing weakly solvated solvents 1,2-dimethoxyethane (DME) or methyl acetate (MA). Through combined first-principles calculations and molecular dynamics simulations, we elucidate the atomic-scale mechanisms underlying the superior performance of DME and MA as solvent molecules. Experimental results demonstrate that the incorporation of DME significantly enhances the cycling stability, with Li–LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) cells maintaining 80% capacity retention after 156 cycles at 4.3 V. This work provides fundamental insights for optimizing commercial LIB electrolytes and paves the way for developing next-generation electrolyte systems.