Ultrathin ZrO2 coating layer regulates Zn deposition and raises long-life performance of aqueous Zn batteries

Rechargeable aqueous zinc metal batteries (ZMBs) have been regarded as one of the promising energy storage technologies for low-cost, use-safe, and large-scale applications. However, Zn metal anode is known to suffer from serious inherent problems of unwanted dendrite growth and side reactions, which significantly affect the cycling stability. Herein, a dense and ultrathin ZrO2 coating is purposely designed on the Zn surface by atomic layer deposition (ALD). The ZrO2 coating thus developed enables uniform Zn deposition, lowers the nucleation overpotential for Zn2+ deposition, and effectively suppresses side reaction of Zn anode, whereby generating an interfacial polarization effect, and thus promoting reversible Zn2+ plating/stripping behavior. Therefore, the Zn anode with optimized ZrO2 coating thickness of 40 nm ZrO2 shows an excellent cycling life. Additionally, the surface protection of ZrO2 is extended to boost the cycling performance of Zn–MnO2 battery, achieving a durable life of over 2500 cycles at 10 C.