In situ-Induced Crystal Facet Engineering to Enhance the Rate Performance of Zn²⁺ Storage

In recent years, aqueous zinc-ion batteries (ZIBs) have shown considerable promise in the energy storage sector, attributed to their inherent high safety and cost-effectiveness. Zn₃V₂O₇(OH)₂·2H₂O (ZVO) has emerged as a promising candidate for Zn²⁺ storage in recent years, owing to its exceptional structural stability that endows it with an excellent cycle life. However, an unsatisfactory rate performance is a limiting factor for its development in ZIBs. Crystal facet engineering can be employed to rationally adjust the number of exposed diffusion channel entrances, thereby effectively enhancing the rate performance of ZIBs. Here, theoretical calculations are employed to analyze the diffusion energy barrier of Zn²⁺, providing guidance for selecting the optimal crystal facet. The obtained ZVO via electrochemical in situ conversion (e-ZVO) with increased exposed diffusion channel entrances of Zn²⁺ was proposed to enhance the rate performance. The modulation of ZVO crystal facet orientation and exposed diffusion channel entrances is achieved by manipulating the adsorption-induced surface energy of (CF₃SO₃)^- on crystal facets. As a result, the e-ZVO achieves a high-rate performance of 57 mAh g^-1 at 50 A g^-1 and a capacity output of 41 mAh g^-1 at 40 A g^-1 even at -20 °C.