Towards stable electrode–electrolyte interphases: Regulating solvation structures in electrolytes for rechargeable batteries

Abstract

Rechargeable batteries are highly in demand to power various electronic devices and future smart electric grid energy storage. The electrode–electrolyte interphases play a crucial role in influencing the electrochemical performance of batteries, with the solvation chemistries of the electrolyte being particularly significant in regulating these interfacial reactions. However, the reaction mechanisms of electrolyte solvation and their specific functions in batteries are not yet fully understood. In this review, we embark on an exploration of the fundamental principles governing solvation and present a comprehensive overview of how solvation structures impact interfacial reactions at the electrode–electrolyte interface. We underscore the significance of interactions among cations, anions, and solvents in shaping electrolyte solvation structures. The primary strategies for controlling solvation structures are also discussed, including the optimization of salt concentrations, solvent interactions, and the introduction of functional cosolvents. Furthermore, we elucidate the oxidation/reduction reaction mechanisms of electrolyte components in different solvation structures and the new understanding of electrolyte additives in modulating interfacial chemistries in batteries. Additionally, we emphasize the importance of incorporating new characterization techniques and theoretical simulations to attain a deeper understanding of the intricate processes taking place within batteries. This review provides an in-depth understanding in solvations and interphasial properties and new ideas for designing advanced functional electrolytes for rechargeable batteries.