Dendrite-Free Zinc Anode for Zinc-Based Batteries by Pre-Deposition of a Cu-Zn Alloy Layer on Copper Surface via an In Situ Electrochemical Oxidation-Reduction Reaction

The prevention of uncontrollable growth of zinc dendrites on the zinc electrodes is one of the key challenges, hindering the widespread commercialization of zinc-based energy storage technologies. Herein, we report a facile method to mitigate dendrite growth on a copper surface by an initial in situ coating of a Cu-Zn alloy layer, before zinc deposition. During further zinc deposition, the initially formed Cu-Zn alloy layer provides uniform nucleating sites and promotes homogeneous zinc deposition. A symmetrical cell, assembled using a Cu-Zn/Cu electrode could be stably cycled for over 1000 cycles in ZnSO4 solution, at a current density of 30 mA/cm(2) and a coulombic efficiency of 99.9%. A zinc-air cell, assembled using Zn@Cu-Zn/Cu as the anode and rGO/Co3O4 composite as the cathode, exhibited a very stable performance at a high current density of 50 mA/cm(2) and coulombic efficiency of similar to 93%, for over 400 cycles. After cycling experiments, the X-ray photoelectron spectroscopy and the X-ray diffraction analysis confirmed the formation of the Cu-Zn alloy layer. Hence, the present method provides an easy route for fabricating a dendrite-free zinc electrode, for a wide range of zinc anode-based batteries.