Promoted de-solvation effect and dendrite-free Zn deposition enabled by in-situ formed interphase layer for high-performance zinc-ion batteries

The use of aqueous electrolytes and Zn metal anodes in Zn-based energy storage systems provides several benefits, including competitive energy density, excellent safety, and low cost. However, Zn dendrites growth and slow ion transfer at the electrode/electrolyte interphase reduce the cycle stability and rate capability of the Zn anode. Herein, the V2O5-x interface layer was rationally and controllably constructed on the Zn surface through in situ spontaneous redox reaction between V2O5 and the Zn anode. The V2O5-x interface layer, with an optimized thickness, plays a crucial role in ion screening and de-solvation, leading to a uniform dispersion of Zn2+ions and dendrite-free morphology. Moreover, as Zn2+ transports through the V2O5-x interface layer, the V element in a low-valence state allows the oxygen anions to bind more easily with Zn2+. This interaction enables a fast Zn2+ diffusion channel in the interfacial layer. Consequently, symmetric cells with V@Zn anodes achieve stable plating/stripping for more than 1,400 h at 1 mA cm-2. In particular, the full cell paired with a V2O5 cathode exhibits a capacity of nearly 275.9 mA h g-1 at 5 A g-1 after 2,500 cycles without obvious capacity deterioration, further highlighting the potential for practical applications.