Dual-Functional LiCl Additive for Highly Reversible Zinc Metal Anode

Zinc metal has emerged as a promising candidate for high-capacity and low-cost anodes in aqueous zinc-ion batteries; nevertheless, it encounters serious obstacles, including low cycling stability and poor reversibility, caused by parasitic reactions and the formation of zinc dendrites. Herein, the study proposes a novel nonprotonic dimethylacetamide (DMAC)/ZnCl 2 /LiCl electrolyte that enables both solvation structural modulation of [ZnCl x ] 2-x and the cationic electrostatic shielding effect of [Li(DMAC)] + by controlling the concentration of LiCl. The optimal concentration of LiCl electrolyte (0.28 m ), which results in the highest ratio of [ZnCl 3 ] − , strikes a balance between low desolvation energy and a high mass transfer rate while promoting homoepitaxial deposition of Zn (002). Moreover, inert [Li(DMAC)] + ions, which possess a lower reduction potential, preferentially adsorb onto zinc protrusions, mitigating the tip effect. Leveraging electrolyte engineering, the zinc deposition/stripping process results in impressive long-term stability, surpassing 2,800 cycles, and the Zn||MnO 2 cell also achieves a stable lifespan extending beyond 1400 cycles. The research highlights the potential of LiCl as an additive in the modulation of water-free electrolytes.