ABSTRACT Lithium metal batteries (LMBs) encounter critical challenges at low temperatures due to the sluggish ion transport and unstable lithium deposition. Localized high concentration electrolytes, a representative weak−solvation strategy, have been extended to gel polymer electrolytes with tunable solvation structures and improved low−temperature performance. Herein, a moderately fluorinated segment is selected for the localized high concentration polymer electrolytes (LHCPE) by balancing dilution, salt dissociation, and copolymerization compatibility through side chain screening. Fine−tuning the dilution effect within the polymer matrix enables the formation of anion−rich coordination that maintains structural integrity at low temperatures, reducing reliance on polymer segmental motion and enhancing Li + transport with high ionic conductivities (2.12 × 10 −3 S·cm −1 at 25°C). The compact, anion‐dominated solvation structure promotes the formation of an inorganic−rich solid electrolyte interphase, supporting long−term symmetric cell operation for over 4000 h at room temperature and 2800 h at −20°C. The initial capacity of the Li||NCM811 full cells retained 74.72% and 51.68% of their room‐temperature capacity at −20°C and −40°C, respectively, achieved 92.62% capacity retention after 125 cycles at −20°C and 80.91% after 55 cycles at −40°C. This study provides insight for the rational design of LHCPEs toward high−performance LMBs in extreme environments.
Fu et al. (Mon,) studied this question.