Ultrathin surface coating of Cu enabling long-life Zn metal anodes

Aqueous zinc-ion batteries (AZIBs) are regarded as promising energy storage devices due to their low cost, high capacity, and ecological safety. Nevertheless, the severe dendritic growth and side reactions hinder their practical applicability significantly. Herein, an ultrathin Cu coating layer (~ 200 nm) is decorated on zinc foils via filtered cathodic vacuum arc deposition technology, aiming to achieve high-performance AZIBs. The Cu layer effectively suppresses chemical corrosion and hydrogen evolution reactions and enables preferential (002) Zn deposition during the stripping/plating cycles. Consequently, the Cu@Zn anode represents an elongated cycle life over 4,000 h at 2 mA·cm −2 /2 mAh·cm −2 . Even in conditions of high current density of 5 and 10 mA·cm −2 , the Cu@Zn anode shows prolonged cycling stability exceeding 4000 and 2000 h, respectively. Such advantages also bring high Coulombic efficiency of 99.87% under 5 mAh·cm −2 in Cu@Ti||Zn half-cell over 1500 cycles. Moreover, the Cu@Zn||MnO 2 full cell demonstrates a superior cyclability with a specific capacity of 203 mAh·g −1 after 500 cycles at 1 A·g −1 . Graphical abstract