Dielectric‐Mediated Solvation Chemistry Unlock Ah‐Level Nail‐Penetration‐Resistant TiNb ₂ O ₇ Pouch Cells Operating at −60°C

Abstract

ABSTRACT 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 (TiNb 2 O 7 ) 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||TiNb 2 O 7 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.