Electronic state modulation and defect engineering promote diffusion kinetics of T-Nb₂O₅ for low-temperature lithium-ion batteries

Lithium-ion batteries generally suffer from sluggish charge/mass transfer capability at high rates and low temperatures. Herein, a partially modulated structure of T-Nb₂O₅ is designed by heteroatom doping and vacancy regulation to enhance low-temperature reaction kinetics. We find that the synergistic effect can shorten the band gap, regulate the electronic active states and broaden the lithium-ion diffusion channel, thereby increasing charge transport ability and accelerating low-temperature Li⁺ transport behavior. Meanwhile, the structure modification significantly reduces the lattice expansion from 3.98 to 4.06 Å during the repeated lithiation-delithiation process. Benefiting from the structural advantages, Zr_0.05-Nb₂O₅ anode exhibits an excellent rate performance (136.9 mAh g⁻¹ at 20 C) and an impressive low-temperature cycle life with slight capacity degradation after 550 cycles at −30 °C. A full cell with a LiNi_0.5Co_0.2Mn_0.3O₂ cathode delivers capacity retention of 96.1% after 300 cycles at −30 °C, demonstrating its practical feasibility. This work presents a novel concept to improve low-temperature charge transfer of T-Nb₂O₅ for the development of long-life and fast-charging LIBs.