Self-Adaptive Built-in Electric Fields Drive High-Rate Lithium-Ion Storage in C@Li3VO4 Heterostructures

While the high theoretical capacity and low operating voltage of Li₃VO₄ (LVO) make it an ideal anode material for lithium-ion batteries (LIBs), its unsatisfactory high-rate performance and lack of efficient methods for designing high-rate LVO anodes severely hinder its application in fast-charging LIBs. Herein, self-adaptively tuning the built-in electric field is first adopted and demonstrated as a valid strategy to design high-rate LVO-based anodes, using a specifically designed heterostructure of LVO nanoparticles in situ grown on industrial waste yeast cell wall-derived carbon (C@LVO). A built-in electric field from external LVO to inner C in the C@LVO accelerates Li⁺ diffusion during lithiation. After full lithiation, a new heterojunction of Li_yC@Li_3+xVO₄ forms with a flipped built-in electric field. This adaptive field reversal accelerates Li⁺ diffusion during both lithiation and delithiation, consistently triggering excellent reaction kinetics. The as-synthesized C@LVO anode exhibits an exceptional reversible capacity of 855.0 mAh g⁻¹ and impressive rate performance (500 mAh g⁻¹/5 A g⁻¹). Furthermore, C@LVO‖LiFePO₄ full cell demonstrates excellent fast-charging capability, achieving 223.5 Wh kg⁻¹ at 9.1 kW kg⁻¹, while maintaining 95.8% capacity retention after 2000 cycles. This work provides a new way to construct high-rate LVO-based anodes, which may pave the way for the practical application of LVO.