In Situ Formation of Lattice-Distorted Mn-Based Catalysts Boosting High Energy-Efficiency Aqueous Metal-Air Batteries

Area of Science:

• Electrochemistry
• Materials Science
• Sustainable Energy

Background:

• Rechargeable aqueous metal-air batteries (AMABs) are promising for sustainable energy storage due to safety and cost.
• Sluggish oxygen redox kinetics, particularly in CO2-tolerant near-neutral electrolytes, hinder practical AMAB performance.

Purpose of the Study:

• To develop a novel catalyst strategy for enhancing oxygen redox kinetics in AMABs.
• To improve the efficiency, durability, and CO2 tolerance of AMABs.

Main Methods:

• Introduced Mn2+ into aqueous electrolytes for in situ MnO2 formation.
• Investigated electrodeposited MnO2 with lattice contraction via X-ray diffraction and electrochemical analysis.
• Evaluated catalyst performance in Zn-air and Mn-air battery systems.

Main Results:

• Electrodeposited MnO2 exhibited a 3% lattice contraction, upshifting the d-band center.
• Lattice distortion accelerated oxygen evolution reactions (OER) by optimizing *OOH intermediate formation energy.
• Zn-air batteries showed a 35.9% reduction in OER/ORR overpotential and >1000 h cycling stability.
• Mn-air batteries achieved low overpotential (0.29 V) and high energy efficiency (84.2%).

Conclusions:

• The Mn2+-induced in situ MnO2 formation with lattice contraction is a viable strategy for efficient AMABs.
• This approach enhances OER kinetics and improves battery stability in near-neutral, CO2-tolerant electrolytes.
• The developed method offers a universal strategy for high-performance, durable, and CO2-tolerant AMABs.