Switching Hydrophobic Interface with Ionic Valves for Reversible Zinc Batteries.

Developing hydrophobic interface has proven effective in addressing dendrite growth and side reactions during zinc (Zn) plating in aqueous Zn batteries. However, this solution inadvertently impedes the solvation of Zn 2+ with H 2 O and subsequent ionic transport during Zn stripping, leading to insufficient reversibility. Herein, we propose an adaptive hydrophobic interface that can be switched "on" and "off" by ionic valves to accommodate the varying demands for interfacial H 2 O during both the Zn plating and stripping processes. We validate this concept using octyltrimethyl ammonium bromide (C 8 TAB) as the ionic valve, which can initiatively establish and remove a hydrophobic interface in response to distinct electric-field directions during Zn plating and stripping, respectively. Consequently, the Zn anode exhibits an extended cycling life over 2500 hours with a high Coulombic efficiency of about 99.8%. The full cells also show impressive capacity retention of over 85% after 1000 cycles at 5 A g -1 . Our findings provide a new insight into interface design for aqueous metal batteries. This article is protected by copyright. All rights reserved.