Desolvation Effect Triggered by TiS₂‐TiO₂ Heterostructure for Ultrahigh‐Rate Aqueous Zinc‐Ion Batteries

Abstract Aqueous Zn ion batteries (AZIBs) represent a promising candidate for the next‐generation energy storage and conversion systems due to their high safety and cost‐effectiveness. However, sluggish kinetics arising from interface desolvation processes pose challenges in achieving high‐power density and long cycle life for AZIBs. Here, it is discovered for the first time that heterostructures utilize built‐in electric field forces to promote the desolvation process at the electrode‐electrolyte interface. Density functional theory (DFT) calculations and structural characterization demonstrate that heterogeneous structures simultaneously accelerate the desolvation process and enhance ion diffusion, resulting in the outstanding rate performance (160.9 mA h g⁻¹ at 5 A g⁻¹) of TiS₂‐TiO₂ heterostructures, far exceeding that of a conventional TiS₂ electrode with 14.2% capacity retention. Meanwhile, the insertion/extraction of the desolvated charge carriers reduced the volume change of TiS₂‐TiO₂ material during the charging/discharging processes, enabling the long‐lasting cycling stability (108.6 mA h g⁻¹ after 2000 cycles at 0.5 A g⁻¹). This study provides instructive electrode design strategies for the construction of fast‐charging electrochemical energy storage systems.