TiO₂/FeCoS Heterojunction Anode for Fast-Charging Lithium-Ion Batteries

To develop fast-charging lithium-ion batteries (LIBs), optimizing insertion-type anode structure is crucial for achieving fast lithium-ion diffusion and high electronic conductivity. Here, we combine insertion-type TiO₂ with high-capacity FeCoS to construct a TiO₂/FeCoS heterojunction, which enhances electron/ion transport, lowers the ion diffusion energy barrier, and thereby improves quick-charging performance. The resulting anode exhibits a high reversible capacity of 627.7 mAh g^-1 at 0.1 A g^-1, 2.3 times that of TiO₂. Notably, it gives a remarkable capacity of 241.7 mAh g^-1 at 10 A g^-1 and maintains excellent stability over 10,000 cycles with an ultralow capacity decay of just 0.002% per cycle. Experiments and theoretical calculations confirm the superior performance originates from enhanced Li⁺ ions adsorption and reduced diffusion barrier at the heterointerface, which accelerates Li⁺ insertion/extraction kinetics. This work provides an effective pathway to accelerate electrochemical kinetics and enable fast-charging LIBs.