A dendrite-free Zn@CuxZny composite anode for rechargeable aqueous batteries

Abstract Rechargeable aqueous zinc-ion batteries (ZIBs) are attractive candidates for next-generation batteries because of low cost and high safety merits. However, ZIBs still suffer from the problems of dendrites growth during the electrostripping/electroplating process, leading to low cycling stability and hindering the application of ZIBs. Here, a facile and effective strategy of decorating zinc surface with copper alloy layer is developed. The copper alloy layer can act as a nucleating agent and mitigate Zn dendritic growth by guiding uniform Zn deposition. Symmetrical cells assembled with CuxZny coated Zn (denoted as Zn@CuxZny) electrode can achieve stable cycling for 500 h with a low voltage hysteresis (23 mV) at 1 mA/cm2, compared to bare Zn cell with less than 100 h. The superiority of the prepared anode can also be confirmed by the repeated plating/stripping tests at current density of 0.25, 0.5 and 2 mA/cm2, respectively. More impressively, when paired with a CNT/MnO2 cathode, the full cell with Zn@CuxZny anode can maintains a more than twice the discharge capacity after 1000 cycles than that of the full cell with bare Zn anode (144 vs 57 mAh/g at 1 A/g). This strategy is scalable, versatile and cost-effective for fabricating a broad range of zinc metal anodes.