Electric and Temperature Field-Modulated Periodic Repair of the Electrode/Electrolyte Interface toward Long Cycle Stability of Low-Temperature Li-Ion Batteries

This study tackles the poor low-temperature performance of lithium-ion batteries through a synergistic strategy that modulates electrode–electrolyte interfacial chemistry via coordinated temperature and electric field control. The research uncovers distinct interfacial evolution mechanisms: at −20 °C, strengthened solvent–Li + affinity causes solvation structure reorganization and interfacial deterioration, whereas at 25 °C, enhanced anion participation promotes formation of stable inorganic-rich interphases. Reduced electric field intensity further facilitates the construction of stable interfaces. Based on these findings, a variable-temperature constant-current cycling protocol with periodic room-temperature activation is developed. This approach effectively restores stable interfaces and substantially minimizes polarization, enabling commercial lithium iron phosphate (LFP) batteries to maintain nearly 100% initial capacity after 150 cycles at −20 °C—significantly surpassing conventional strategies (80.4% retention). Notably, this optimization method regulates interfacial chemistry through external field parameters without electrolyte formulation changes, demonstrating both theoretical innovation and engineering practicality. This work provides a novel paradigm for low-temperature battery design by decoupling interfacial regulation from material modification.