Dual-phase intergrown niobium-tungsten oxides for fast ion diffusion under extreme operating environments

Limited ion diffusion poses a major challenge for anode materials in lithium-ion batteries operating under extreme environments, where sluggish Li+ transport and poor electronic conductivity severely deteriorate lithium-ion storage performance. Since ion diffusion pathways are intrinsically governed by the crystal structure, rational structural regulation is essential to enable low-energy diffusion pathways. Herein, vanadium-doped Nb₂WO₈ is designed to construct a dual-phase heterostructure composed of Nb₂WO₈ and Nb₁₄W₃O₄₄, where vanadium incorporation introduces local lattice distortion and charge-compensation effects that destabilize the Nb₂WO₈ framework. The resulting dual-phase architecture introduces abundant heterointerfaces, which provide structurally disordered regions with reduced Li+ diffusion energy barriers and facilitate ion transport. Meanwhile, vanadium doping effectively enhances the electronic conductivity of the composite, synergistically improving charge-transfer kinetics. The dual-phase niobium-tungsten oxides exhibit high reversible capacities at −60 °C. A full cell assembled with LiCoO₂ delivers a capacity retention of 80.05% after 100 cycles at 0.5 C and −40 °C. This work provides new insights into the structural design of high-performance anode materials for extreme-environment lithium-ion batteries.