Suppressing the Exacerbated Hydrogen Evolution of Porous Zn Anode with an Artificial Solid-Electrolyte Interphase Layer

Rechargeable Zn batteries are widely studied as aqueous, safe, and environmentally friendly alternatives to Li-ion batteries. The 3D porous Zn anode has been extensively reported for suppressing Zn dendrite growth and accelerating the electrode kinetics. However, we demonstrate herein that the undesirable hydrogen evolution reaction (HER) is also exacerbated for porous Zn electrode. Therefore, a polytetrafluoroethylene (PTFE) coating is further applied on the porous Zn serving as the artificial solid-electrolyte interphase (SEI), which is demonstrated to effectively inhibit the hydrogen evolution and maintain the Zn plating kinetics. By utilizing the synergistic effects of the porous morphology and artificial SEI layer, better performances are obtained over porous Zn or bare Zn foil, including dendrite-free Zn plating/stripping up to 2000 h at 2 mA cm-2 and extended cycling in the Zn||V2O5 cell. This work suggests two complementary strategies for achieving simultaneously dendrite-free and side-reaction-suppressed Zn batteries.