Localized Negatively Charged Interfaces for Seawater Electrolyte-Based Zinc-Air Batteries

Seawater electrolyte-based zinc-air batteries (S-ZABs) are considered the promising choice for highly efficient marine power supply, owing to their high specific energy, low cost, and eco-friendliness. However, the air-cathode suffers from the sluggish oxygen reduction reaction (ORR) kinetics together with the severe adsorption of Cl- in seawater electrolytes, which severely limits the service life and efficiency of S-ZABs. Herein, precisely decorating axially coordinated Cl ions (Cl-) on Fe atomic sites (Cl-FeSA/NC) to construct a local negatively charged interface to inhibit the adsorption of Cl- is proposed, which exhibits a desirable ORR activity, and good stability with almost no loss in electrocatalytic performance after long-term stability test. Moreover, the assembled battery achieves a peak power density of 208.0 mW cm-2, which is 1.45 times higher than commercial Pt/C-based S-ZABs. Density functional theory calculations reveal that the axially coordinated Cl- not only constructs a local negatively charged interface to inhibit the corrosion and poisoning of Fe active sites by Cl-, but also regulates the electronic states of Fe active sites to optimize adsorption/desorption energy of intermates, thus improving the electrocatalytic activity and stability of Cl-FeSA/NC.