An Anion Outer-Regulated Electrolyte with Rapid Desolvation Effects Enables High-Voltage Lithium Metal Batteries†

Abstract

Ion/solvent-solvent interactions have garnered extensive attention to construct anion-dominated solvation structure for high-voltage batteries. While it is acknowledged that the macroscopic dragging effect can reduce desolvation energy, there remains a significant gap in the in-depth analysis of the dynamic mechanisms underlying electron transfer. This deficiency hampers the ability to formulate high-performance electrolytes in a targeted and effective manner. In this study, we propose an anion outer-regulated electrolyte (AORE) by interfering with the electronic interactions between solvated anions and peripheral solvents to reconstruct the dynamic solvation structure and accelerate the desolvation process. Combining multispectral characterization and theoretical calculations, the deep electron transfer nature of the anionic drag effect is revealed, confirming that AORE can significantly enhance the lithium-ion transference number (0.8) and ion conductivity (8.24 mS cm−1), as well as the flame retardant properties. The assembled LiCoO2 || Li cell maintains a retention ratio of 90.41% capacity even after 600 cycles at a high voltage of 4.6 V, and the capacity loss of the pouch battery is only 8% after 100 cycles, which can successfully provide takeoff and hovering power for micro unmanned aerial vehicles. This study provides a new paradigm for advanced electrolyte design through molecular charge engineering strategies.