Reversible Zinc Metal Anode for Aqueous BatteriesS. Himmelstein | April 17, 2018
Metallic zinc represents an ideal anode material for aqueous batteries because of its high theoretical capacity (820 mA h g–1), low potential (−0.762 V versus the standard hydrogen electrode), high abundance, low toxicity and intrinsic safety. However, irreversibility issues evident in terms of low coulombic efficiency and dendrite formation plague aqueous Zn chemistry.
University of Maryland researchers designed a water-based zinc battery to overcome these limitations. The aqueous electrolyte used is based on metallic Zn and lithium salts at high concentrations. The resulting rechargeable device could offer a low-cost, safe alternative for consumer electronics, cars and electrical grid storage. The aqueous zinc battery could also eventually be used in extreme conditions to improve the performance of safety-critical vehicles such as those used in aerospace, military and deep-ocean environments.
Problems posed by battery fire incidents affecting cell phones, laptops and electric vehicles are eliminated with this battery chemistry, which also maintains energy densities comparable to or exceeding those of conventional lithium-ion systems. Reversibility was realized by altering the solvation sphere structure of zinc cation. Dendrite growth during usage and recharging, as well as sustained water consumption, are not performance issues with this battery design.