Tailored Solvation and Interface Structures by Tetrahydrofuran‐Derived Electrolyte Facilitates Ultralow Temperature Lithium Metal Battery Operations

Abstract Ineffectiveness of Li‐ion batteries (LIBs) in cold climates hinders electronics to work in various conditions including frigid environments, despite high demands. Given that intrinsic properties of LIB materials cause this problem, optimized cell chemistries ultimately are required for low‐temperature usage. In this study, Li‐metal batteries (LMBs) composed of a Li‐metal anode (LMA) stabilized by a localized high‐concentration electrolyte (LHCE) are found to significantly enhance low‐temperature performance. The LHCE allows the LMA to have compact and regular deposition and excellent plating/stripping efficiency at sub‐zero temperatures. The LHCE produces an inorganic‐rich solid‐electrolyte interphase with larger amounts of Li2O/LiF interfaces, dominance of ion aggregates in Li+ solvation, and enhanced Li+ transport, which can greatly improve the LMA stability. LMB full cells based on LiNi0.8Co0.1Mn0.1O2 cathodes with the tailored electrolyte show high retentions of 75 and 64 % at −20 and −40 °C, respectively. Furthermore, the LMB configuration retains its charge−discharge capability even at −60 °C.