Janus-like WC-Co Heterostructures Enable Orbital-Level Modulation for Durable Seawater Zinc-Air Batteries

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Seawater-based zinc-air batteries (SWZABs) are promising for marine energy due to high energy density and electrolyte availability.
• Practical use is hindered by chloride corrosion, catalyst poisoning, and slow oxygen reduction/evolution reaction (ORR/OER) kinetics.

Purpose of the Study:

• To develop a durable and highly active bifunctional catalyst for SWZABs that overcomes limitations in marine environments.
• To investigate the catalytic mechanism and electronic modulation effects of a novel heterostructured catalyst.

Main Methods:

• Fabrication of a heterostructured catalyst (CoNP/WC@CoNC) comprising WC-Co nanoparticles and atomically dispersed Co sites on N-doped carbon.
• In situ electrochemical characterization and computational calculations to analyze catalytic activity and electronic structure.
• Performance testing of the catalyst in SWZABs, evaluating power density and lifespan.

Main Results:

• The CoNP/WC@CoNC catalyst demonstrated efficient bifunctional oxygen electrocatalysis under seawater conditions.
• WC acted as an electronic modulator, downshifting the Co d-band center via W 5d-Co 3d hybridization, enhancing ORR/OER kinetics.
• The catalyst exhibited suppressed chloride-induced corrosion, a small ORR/OER potential gap (0.68 V), and a peak power density of 233.4 mW cm⁻².
• The derived SWZAB achieved a superior lifespan exceeding 2500 hours.

Conclusions:

• The heterostructured catalyst CoNP/WC@CoNC provides a robust solution for seawater-based energy devices.
• Utilizing 5d transition-metal carbides as interfacial electronic modulators is an effective strategy for designing advanced electrocatalysts.
• This research paves the way for durable and high-performance catalysts in challenging marine environments.