Grooved Cathode Enabled High Areal Capacity Lithium-Air Batteries.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Thick cathodes in lithium-air batteries (LABs) face challenges with oxygen (O2), ion, and electron transport.
• This limits catalyst active site accessibility, hindering high areal capacity and practical application of LABs.

Purpose of the Study:

• To design a heterostructure catalyst (Fe3O4@MnO2) for improved Li-air battery performance.
• To precisely tune electrode tortuosity for enhanced reactant and product transport.

Main Methods:

• Fabrication of a Fe3O4@MnO2 heterostructure catalyst.
• Modulation of porous electrode structure to achieve specific tortuosities (5.05, 2.58, 1.31).
• Characterization of electrode architecture and electrochemical performance.

Main Results:

• Optimized cathode with low tortuosity (1.31) and vertically aligned channels.
• Demonstrated rapid O2/Li+ transport and accommodation of discharge products.
• Achieved a record areal capacity of 23.01 mAh cm-2 in ambient air.
• Sustained 1600 hours of cycling at 6 mAh cm-2.

Conclusions:

• The grooved cathode design with Fe3O4@MnO2 catalyst significantly enhances Li-air battery performance.
• Precisely controlled electrode tortuosity is crucial for practical ambient-air LABs.
• This work bridges structural engineering with electrochemical performance breakthroughs.