Dielectric-ion-conductive ZnNb$_2$O$_6$ layer enabling rapid desolvation and diffusion for dendrite-free Zn metal batteries

Rechargeable aqueous zinc-metal batteries (AZMBs) are promising candidates for large-scale energy storage systems due to their low cost and high safety. However, their performance and sustainability are significantly hindered by the sluggish desolvation kinetics at the electrode/electrolyte interface and the corresponding hydrogen evolution reaction where active water molecules tightly participate in the Zn (H$_2$O)$^{2+}$$_6$ solvation shell. Herein, learnt from self-generated solid electrolyte interphase (SEI) in anodes, the dielectric but ion-conductive zinc niobate nanoparticles artificial layer is constructed on metallic Zn surface (ZNB@Zn), acting as a rapid desolvation promotor. The zincophilic and dielectric-conductive properties of ZNB layer accelerate interfacial desolvation/diffusion and suppress surface corrosion or dendrite formation, achieving uniform Zn plating/stripping behavior, as confirmed by electronic/optical microscopies and interface spectroscopical measurements together with theoretical calculations. Consequently, the as-prepared ZNB@Zn electrode exhibits excellent cycling stability of over 2000 h and robust reversibility (99.54%) even under high current density and depth of discharge conditions. ... mehrMeanwhile, the assembled ZNB@Zn-based full cell displays high capacity-retention rate of 80.21% after 3000 cycles at 5 A g$^{-1}$ and outstanding rate performance up to 10 A g$^{-1}$. The large-areal pouch cell is stabilized for hundreds of cycles, highlighting the bright prospects of the dielectric but ion-conductive layer in further application of AZMBs. Ó 2024 Science Press and Dalian