In-situ grown porous protective layers with high binding strength for stable Zn anodes

Zinc (Zn) metal is a promising anode material for aqueous batteries. Unfortunately, undesirable issues such as dendrite growth, intricate side reactions, and limited reversibility restrict its large-scale applications. Herein, a porous ZIF-8 protecting layer is in-situ constructed on the Zn surface (named as Zn@ZIF8) to effectively manipulate the Zn plating/stripping behavior. The in-situ formation of porous ZIF-8 layer not only shows excellent bonding strength with Zn substrate but also affords low nucleation overpotential and uniform Zn²⁺ electrolyte flux and reduces intricate side reactions, thus leading to homogeneous Zn plating/stripping behavior. These merits enable substantially stable symmetric Zn cells and Zn-based electrochemical energy storage devices. In detail, the Zn ion capacitor based on Zn@ZIF8 anodes demonstrates superior cycling stability (∼100% capacity retention after 20 000 cycles), much better than those with bare Zn anodes. This work presents a facile and effective approach for manipulating Zn dendrites growth and realizing ultra-stable Zn-based batteries.