Aqueous zinc metal batteries are attractive for long duration and grid scale energy storage because they are intrinsically safe, sustainable, and based on low cost, abundant materials. However, their broader adoption is still limited by challenges at the zinc metal anode, including dendrite formation and parasitic reactions associated with water reduction. These processes undermine reversibility and make it difficult to achieve long term cycling stability at practical current densities.

Our work introduces an electrolyte design strategy that enables stable zinc plating and stripping without relying on traditional highly concentrated water in salt formulations. We show that the local zinc ion coordination environment can be tuned to resemble water in salt behavior even in moderately dilute electrolytes when using coordinating, non-fluorinated anions such as acetate. This provides the interfacial and solvation benefits typically associated with concentrated systems while preserving the high conductivity, low viscosity, and lower environmental footprint of dilute electrolytes. The results highlight that extreme salt concentrations are not necessary for dendrite suppressed zinc deposition; instead, the coordination strength and identity of the anion emerge as key molecular design parameters.

In parallel, we investigate complex zinc electrolyte systems that contain supporting salts and demonstrate how their composition alters zinc ion solvation, ion transport, and concentration polarization, all of which strongly influence dendrite morphology and high rate performance. Because standard approaches such as the Bruce Vincent method do not accurately quantify cation transference numbers in multicomponent electrolytes, we developed a new measurement framework that resolves the transport contributions of zinc ions and the accompanying ions in solution. This enables a mechanistic link between electrolyte composition, transport behavior, and interfacial stability.

Taken together, these insights establish a path toward environmentally benign, low cost aqueous electrolytes that support stable, high-rate zinc metal cycling. By coupling controlled solvation chemistry with accurate ion transport characterization, our work provides design principles for next generation zinc-based batteries that can meet the needs of grid energy storage systems.