Temperature-Adaptive Electrolyte Enables Stable Cycling of Liquid Lithium Pouch Cells at ≥100 °C

Development of lithium batteries capable of operating over ultrawide temperature ranges, from subzero to temperatures ≥ 100 °C, is urgently needed yet remains highly challenging. This is primarily due to the inherent trade-off between sluggish kinetics at low temperatures and poor structural stability at high temperatures and high voltages. Herein, by systemically investigating the temperature responsiveness of various anions, a temperature-adaptive weakly solvating electrolyte (TAE) is elaborately designed in which the solvation structures are sensitive to temperature. As a result, TAE not only exhibits a higher Li⁺ transference number and ionic conductivity comparable to commercial electrolytes at ambient and subzero temperatures, but also leads to anion-derived gradient inorganic-rich interphases at high temperatures/cutoff voltages. Consequently, LiCoO₂ || Li cells using TAE achieve capacity retentions of 89.6% after 500 cycles at ambient temperature and a cutoff voltage of 4.5 V, and 90.8% after 450 cycles at 80 °C. Moreover, 6.5 Ah pouch lithium-ion cells using TAE, with enhanced safety and ultrawide temperature ranges from -30 to 130 °C, deliver a capacity retention of 86.1% after 100 cycles at 100 °C. Notably, even at 120 °C, the cells retain 71.1% of their initial capacity over 60 cycles without significant swelling. This strategy empowers lithium batteries to autonomously adapt to external temperature, enabling reliable operation across diverse extreme environments.