Seawater-based electrolyte for zinc–air batteries

Aqueous zinc–air batteries (ZABs) are highly regarded as a promising electrochemical energy storage device owing to high energy density, low cost, and intrinsic safety. The employment of seawater to replace the currently used deionized water in electrolyte will bring great economic benefits and broaden the application occasions of ZABs. However, ZABs using seawater-based electrolyte remain uninvestigated without an applicable cathode electrocatalyst or a successful battery prototype. Herein, seawater-based electrolyte is successfully employed in ZABs with satisfactory performances. The influence of chloride anions on the cathode electrocatalytic reactivity and battery performance is systemically investigated. Both noble-metal-based and noble-metal-free electrocatalysts are applicable to the chloride-containing alkaline electrolyte. Further evaluation of ZABs with seawater-based electrolyte demonstrates comparable battery performances with the conventional electrolyte in terms of polarization, capacity, and rate performance. This study demonstrates a successful prototype of seawater-based ZABs and enlightens the utilization of natural resources for clean and sustainable energy storage.