Delocalized electronic engineering of TiNbO enables low temperature capability for high-areal-capacity lithium-ion batteries.

High areal capacity and low-temperature ability are critical for lithium-ion batteries (LIBs). However, the practical operation is seriously impeded by the sluggish rates of mass and charge transfer. Herein, the active electronic states of TiNbO material is modulated by dopant and O-vacancies for enhanced low-temperature dynamics. Femtosecond laser-based transient absorption spectroscopy is employed to depict carrier dynamics of TiNbO, which verifies the localized structure polarization accounting for reduced transport overpotential, facilitated electron/ion transport, and improved Li adsorption. At high-mass loading of 10 mg cm and -30 °C, TNO@N microflowers exhibit stable cycling performance with 92.9% capacity retention over 250 cycles at 1 C (1.0-3.0 V, 1 C = 250 mA g). Even at -40 °C, a competitive areal capacity of 1.32 mAh cm can be achieved. Such a fundamental understanding of the intrinsic structure-function put forward a rational viewpoint for designing high-areal-capacity batteries in cold regions.