Citric acid etched zinc anode surface to improve the stability of aqueous zinc-ion battery

Aqueous zinc-ion batteries (AZIBs) are expected to be the next generation of energy storage devices, but severe dendrite growth hindering the large-scale application of AZIBs. In this paper, a citric acid (CA) etching method is used to optimize zinc anode, which is referred to as CA-Zn. After citric acid etching, the zinc anode surface was exposed to a high proportion of (002) crystal planes, and the stable (002) crystal planes inhibited the formation of zinc surface by-products. Moreover, acid etching etched micro-grooves on the zinc surface, which increased the electrochemically active surface area of the zinc anode. And the plating/stripping kinetics of Zn/Zn2+ was enhanced. Consequently, the CA-Zn symmetric battery has a stable cycle of 550 h at 1 mA cm−2 and 1 mAh cm−2. AZIBs composed of CA-Zn and activated carbon showed a specific capacity of up to 83.5 mAhg−1 and CE close to 100% during cycling 1500 cycles at a current density of 0.5 A g−1. This paper explores a new method to protect zinc metal by citric acid etching, which provides a new idea for future research.