Dielectric-Mediated Solvation Chemistry Unlock Ah-Level Nail-Penetration-Resistant TiNb₂O₇ Pouch Cells Operating at −60°C

Ultra-low-temperature lithium-ion batteries face challenges such as sluggish ion transport and uncontrolled dendrite growth. Herein, we propose in situ tuning interfacial kinetics by coupling dielectric-mediated solvation engineering with niobium-based oxides (TiNb₂O₇) anode to enhance low-temperature performance. Theoretical calculations and in situ characterizations indicate that the dielectric-mediated solvation design possesses a weaker solvation ability and anion-rich inner solvation shells conducive to regulating interfacial chemistry. This regulatory mechanism improves the rate capability (208.9 mAh g⁻¹ at 50 C) of Li||TiNb₂O₇ cells and cycling stability with negligible degradation over 4500 cycles at −30°C. The assembled 2 Ah-level pouch cell retains the capacity retention of 88.0% after 3500 cycles at −30°C and remains operational even at −60°C. Even at nail penetration conditions, the pouch cell exhibits neither smoke nor fire, demonstrating exceptional safety. This work provides a valuable guideline for molecular-level electrolyte design in developing extreme-condition batteries.