Molecular tailoring of electrolyte solvents for high-performance lithium–metal batteries beyond temperature and voltage boundaries

Abstract

Electrolyte optimization is recognized as a critical strategy for enhancing both the long-term cycling stability and safety performance of lithium-ion batteries. Modified electrolytes must possess the following critical properties, including suppressed decomposition reactions, reduced viscosity at low temperatures, and enhanced ionic transport capabilities, while ensuring compatibility with high-voltage cathodes and optimizing the formation of both solid electrolyte interphases (SEI) and cathode electrolyte interphases (CEI). With the inherent limitations of traditional carbonate-based systems, emerging solvents including fluorinated, ether, sulfone and siloxane-based solvents demonstrate significant potential due to their intrinsic safety and wide temperature adaptability. Fluorinated solvents reduce the formation of lithium dendrites to improve safety, and ether-based solvents have low viscosity and excellent low-temperature performance for extreme environments, while sulfone and siloxane-based solvents exhibit excellent thermal stability and interfacial compatibility to extend cell longevity, respectively. Through synergistic molecular design and experimental optimization, such advanced electrolyte systems not only underpin the development of high-energy-density lithium-ion batteries but also establish the basis for breakthroughs in energy storage technology, especially in electric vehicles, renewable energy systems and operation under extreme conditions. Future research should prioritize innovations in high-performance electrolytes that will accelerate the progress of the global energy transition and contribute to carbon neutrality objectives.