Establishing Ohmic contact with ultra-thin semiconductor layer through magnetron sputtering for dendrite-free Zn metal batteries.

The improvement in reversibility and kinetics for Zn metal anodes is crucial to facilitate the further application of aqueous zinc ion batteries. However, the abnormal surface-caused dendrites and parasitic reactions significantly impede the commercial application. Herein, we established Ohmic contact by fabricating an ultrathin semiconductor ZnTe (∼150 nm) layer on the Zn surface via magnetron sputtering to form an electron enrichment region for zinc ions attraction. Particularly, the ZnTe with a higher work function than that of Zn could render a spontaneous electron transfer from Zn to ZnTe, accelerating the zinc ions diffusion, and repelling water and negative sulfate radicals. As a result, the ultrathin ZnTe layer decreases the nucleation and deposition barrier of Zn leading to homogeneous deposition, and restrains the Zn from corrosion and hydrogen evolution reaction. The ZnTe-modified symmetric cells can stably cycle for over 2,400 h and 1,100 h at current density 1 mA cm with area capacity of 1 mAh cm and 5 mAh cm, respectively. The full cell matched with CaVO·nHO shows a 63 % capacity retention after 3,000 cycles at 3 A/g. Our work demonstrates that the construction of Ohmic contact could be an effective way to obtain highly reversible Zn anodes and promote the development of aqueous zinc ions batteries.