A Weak‐Aggregation Electrolyte Enables Lithium‐Ion Capacitors at Ultra‐Low Temperature

ABSTRACT The operation of low‐earth orbit satellites, Antarctic research stations, and certain extreme cold environments demands energy storage devices (ESDs) capable of functioning at −100°C or lower. Conventional electrolytes are limited by sluggish ion transport and unstable electrode‐electrolyte interphases at low temperatures, severely degrading the performance of electrochemical ESDs under extreme cold. Herein, we report a weak‐aggregation (AGG‐w) electrolyte reconciling bulk‐phase ion transport with interfacial kinetics at ultra‐low temperatures (ULT). This is achieved through the strategic incorporation of unilaterally fluorinated motif as strong electron‐withdrawing group, which enhances steric hindrance and reconfigure molecular dipole to reinforce dipole–dipole interaction with the solvents anchored in the primary solvation shell. Such restructuring enables unprecedented solvent‐anion cooperativity by weakening Li + ‐dipole interaction and promoting greater anion participation, thereby accelerating desolvation kinetics, reducing interfacial resistance, and simultaneously preserving low viscosity and high ionic conductivity at ULT. Notably, 1100 F real pouch cells with AGG‐w electrolyte maintain 97.9% capacity retention after 7 months of continuous operation at −40°C and demonstrate emerging discharge capability at −100°C, a milestone never previously reported. This work underscores weak‐interaction engineering as a critical paradigm for electrolyte design and establishes a generalizable strategy for high‐performance electrochemistry in extreme conditions.