Dimensionality Reduction Engineering to Construct a Highly Stable Zn Powder Anode in Aqueous Zn-Ion Batteries

Three-dimensional (3D) Zn powders are usually used as anode materials for aqueous zinc-ion batteries, but the problems of dendrites, structural instability, hydrogen generation, and side reactions caused by their large activity and special spherical structure greatly limit the stability of the anode. The idea of dimensionality reduction for the Zn powders by using mechanical ball milling to design a stable two-dimensional (2D) Zn powder anode is proposed in this work. The special planar structure of the 2D-Zn powder displays significant advantages in buffering the formation of dendrites, side reactions, and hydrogen generation, improving the stability of the anode. As a result, the 2D-Zn powder anode can be cycled stably for 90 h in the symmetrical cell at 2 mA cm^-2/1 mAh cm^-2, which is longer than the 3D-Zn (<1 h). In addition, the cycle life of 2D-Zn is nearly four times that of 3D-Zn in the MnO₂ full cell at 1 A g^-1. Therefore, the change in the dimensions of the Zn powder greatly enhances the stability of the anode.