Solvent Descriptors Guided Wide‐Temperature Electrolyte Design for High‐Voltage Lithium‐Ion Batteries

Abstract Lithium‐ion batteries are increasingly required to operate under harsh conditions, particularly at high temperatures above 55 °C. However, existing electrolytes suffer from inadequate thermal stability and significant interphasial side reactions. Moreover, there is a lack of clear guidelines for developing electrolytes that can withstand high temperatures. Here a solvent screening descriptor is introduced based on dual local softness and dielectric constant. The findings indicate that solvents with moderate dielectric constants and low reactivity are ideal candidates for high‐temperature electrolytes. Among the solvents evaluated, tetraethyl orthosilicate (TEOS) is identified as a suitable option and is utilized to formulate a localized high‐concentration electrolyte (TEOS‐based LHCE). Remarkably, the 1‐Ah LiNi 0.8 Co 0.1 Mn 0.1 ||graphite pouch cell utilizing this TEOS‐based LHCE demonstrates 95.8% capacity retention after 300 cycles at 60 °C. Interphasial analysis reveals that the TEOS‐based LHCE promotes the formation of thin, uniform LiF‐rich interphases, effectively suppressing interfacial side reactions at elevated temperatures. This screening strategy not only enhances the understanding of electrolyte performance but also paves the way for high‐throughput screening of electrolytes suitable for wide‐temperature lithium‐ion batteries.