A Molecular Catalyst-Driven Sustainable Zinc-Air Battery Assembly

Area of Science:

• Electrochemistry
• Materials Science
• Renewable Energy

Background:

• Efficient electrocatalysts are crucial for metal-air batteries, particularly for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER).
• Molecular catalysts offer tunable properties but often lack stability in battery environments.

Purpose of the Study:

• To develop a robust, bifunctional electrocatalyst for ORR and OER in alkaline media.
• To integrate this catalyst into a quasi-solid-state zinc-air battery (ZAB) and evaluate its performance.

Main Methods:

• Covalent tethering of a molecular cobalt complex onto a functionalized silica surface.
• Characterization using X-ray absorbance spectroscopy (XAS).
• Assembly and testing of a quasi-solid-state ZAB using the catalyst on carbon paper, zinc foil, and a gel electrolyte.

Main Results:

• The molecular cobalt catalyst on silica demonstrated effective bifunctional ORR and OER activity in alkaline media.
• XAS confirmed the catalyst retained its molecular integrity during catalysis.
• The quasi-solid ZAB exhibited high power density (60 mW cm⁻²), specific capacity (818 mAh g⁻¹), energy density (757 Wh kg⁻¹), and long cycle life (28 h).

Conclusions:

• The developed molecular catalyst-silica composite is a highly effective and stable bifunctional ORR/OER electrocatalyst.
• The quasi-solid ZAB demonstrates significant potential for practical applications, powering electronic devices with its high energy output and stability.