Superdurable Bifunctional Oxygen Electrocatalyst for High-Performance Zinc-Air Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Rechargeable zinc-air batteries require efficient bifunctional electrocatalysts for oxygen reduction (ORR) and oxygen evolution (OER).
• Developing catalysts with high activity and durability is crucial for practical applications.
• Precise control over atomic and electronic structures is needed to achieve synergistic effects.

Purpose of the Study:

• To develop a novel bifunctional electrocatalyst for enhanced ORR and OER performance in zinc-air batteries.
• To investigate the synergistic effects of doping ruthenium dioxide with manganese at the atomic level.
• To evaluate the catalytic activity, durability, and overall battery performance.

Main Methods:

• Synthesis of atomic-scale Mn-doped RuO2 (Mn-RuO2) bimetallic oxide.
• Electrochemical characterization of ORR and OER activity and durability using techniques like cyclic voltammetry (CV).
• Fabrication and testing of zinc-air batteries with Mn-RuO2 catalysts.
• Theoretical calculations (e.g., DFT) to understand the electronic structure and adsorption properties.

Main Results:

• Mn-RuO2 exhibited remarkable ORR/OER activity with a low potential difference (ΔE) of 0.64 V.
• The catalyst demonstrated exceptional durability, with negligible decay after 250,000 CV cycles (ORR) and 30,000 CV cycles (OER).
• Zinc-air batteries using Mn-RuO2 showed high power density (181 mW cm-2) and ultralong lifespans at various current densities.

Conclusions:

• Mn-doped RuO2 is a highly promising bifunctional electrocatalyst for rechargeable zinc-air batteries.
• Atomic-scale doping optimizes the electronic structure, leading to enhanced catalytic performance and durability.
• The catalyst's performance is attributed to optimized valence states and d-band centers for intermediate adsorption.