Yimei Chen1
University of Alberta1
The practical application of aqueous zinc-ion batteries for large-grid scale systems is still hindered by uncontrolled zinc dendrite and side reactions. Regulating the electrical double layer via the electrode/electrolyte interface layer is an effective strategy to improve the reversibility and stability of Zn anodes. Herein, the ultrathin zincophilic ZnS layer synthesized via a facile electrodeposition method is selected as a model regulator. At a given cycling current, the cell with Zn@ZnS electrode displays a lower potential drop over the Helmholtz layer across the electrode surface and a suppressed diffuse layer, indicating the regulated charge distribution and decreased electric double layer repulsion force. This protective layer also enables redistributed uniform electric fields and highly suppressed side reactions. Consequently, the cell with the ZnS protection layer exhibits a long cycling stability of around 3000 hours at 1mA cm<sup>-2</sup>, accompanied by a high reversibility of 98.9% over 2500 cycles at 5mA cm<sup>-2</sup>. When coupled with I<sub>2</sub>/AC cathode, the cell demonstrates a high rate performance of 160 mAh g<sup>-1</sup>at 0.1 A g<sup>-1</sup> and long cycling stability of over 10000 cycles at 10A g<sup>-1</sup>. The Zn||MnO<sub>2</sub> also sustains both high capacity and long cycling stability of 130 mAh g<sup>-1</sup> after 1200 cycles at 0.5A g<sup>-1</sup>.