Dynamic reconstruction of Ni-Zn alloy solid-electrolyte interface for highly stable Zn anode

Aqueous zinc ion batteries (AZIBs) are ideal candidates for large-scale battery storage, with a high theoretical specific capacity, ecological friendliness, and extremely low cost but are strongly hindered by zinc dendrite growth. Herein, Ni-Zn alloy is artificially constructed as a solid-electrolyte interface (SEI) for Zn anodes by electrodeposition and annealing. The Ni-Zn alloy layer acts as a dynamic shield at the electrode/electrolyte interface. Interestingly, the zinc atoms migrate out of the electrode body during zinc stripping while merging into the electrode body during the plating. In this way, the Ni-Zn alloy is able to guide the zinc deposition in the horizontal direction, thereby suppressing the formation of dendrite. Benefiting from those, the Ni-Zn alloy symmetric cell shows a greatly improved cycle life and is able to operate stably for 1,900 h at a current density of 0.5 mA·cm⁻². The present study is a strategy for negative electrode protection of AZIBs.