Silver nanoflake-mediated anode texture control enabling deep cycling of aqueous zinc-ion batteries

The escalating popularity of aqueous zinc-ion batteries has prompted substantial research efforts directed at mitigating zinc dendrites and parasitic reactions. Modifying Zn foil electrodes with Ag metal/alloy has emerged as an efficacious strategy owing to the exceptional zincophilicity and remarkable electrical conductivity of Ag. Nevertheless, previous studies predominantly rely on either 3D architectures or Ag nanowires/particles. The former approach may increase costs and compromise energy density, while the latter inadequately guides planar zinc deposition. In this work, Ag nanoflakes synthesized by a solution method are employed to control Zn anode texture through a facile drop-casting technique. The nanoflake morphology facilitates the horizontal arrangement of Ag modification layer, thereby readily promoting horizontal zinc deposition. It is also found that the Ag nanoflakes can improve electrolyte wettability, augment anti-corrosion ability, homogenize electric field, diminish nucleation overpotential, reduce desolvation activation energy, impede two-dimensional Zn2+ ion diffusion, reduce exchange current density, lower electrochemical impedances, and result in the formation of AgZn3 alloy. Correspondingly, the zinc stripping/plating reversibility is significantly improved, accompanied by considerably inhibited parasitic reaction, contributing to the realization of deep cycling for both Zn//Zn cell and Zn//MnO2 battery. This study unveils a viable morphology-tailored methodology to achieve dendrite-free characteristic.