Interfacial Confinement Effect of Self-Adsorbed Monolayer Enables Highly Reversible Zn Metal Anodes

The practical applications of aqueous Zn metal batteries are promising, yet still impeded by the corrosion reactions and dendrite growth on the Zn metal anode. Here, a self-adsorbed monolayer (SAM) is designed to stabilize the Zn metal anode. Theory and experiment results show that the interfacial confinement effect of the SAM, for one thing, greatly suppresses the corrosion reactions through the H₂O-poor inner Helmholtz plane because of the steric-hindrance effect, and for another, alleviates the Zn²⁺ concentration gradient on the anode surface through the Zn²⁺ enrichment behavior and eventually inhibits the dendrite growth. Consequently, the Zn||Cu cell maintains a Coulombic efficiency of 99.3% at 10 mA cm^-2/1 mAh cm^-2 for 2000 cycles, and the Zn||Zn cell can stably cycle for 1400 h at 1 mA cm^-2/1 mAh cm^-2. Additionally, the NVO||Zn pouch cell shows impressive cycling stability (over 200 cycles) and low gassing behavior at 3 A g^-1. This work provides a novel perspective for the interface engineering of Zn metal anodes.