Turning Cotton to Self-Supported Electrocatalytic Carbon Electrode for Highly Efficient Oxygen Reduction

Exploring self-supported electrodes with effective oxygen reduction reaction (ORR) activity and durability is of great significance for the future development of metal-air batteries and fuel cells. However, there remain serious challenges in identifying suitable materials and developing sustainable fabrication processes to achieve highly efficient, durable and low-cost self-supported air cathodes. In this work, we report a facile and environmentally friendly method to fabricate electrocatalytic carbon electrodes from commercial cotton fabrics with excellent ORR activity. The iron and nitrogen co-doped carbon fabrics possess outstanding ORR catalytic performance comparable with that of Pt/C, with an onset potential of 0.92 V (vs. RHE) and an electron transfer number close to 4. The experimental results have shown that our carbonisation process can give a high specific surface area (1769 m²/g) with a hierarchical porous structure. Doping leads to the formation of Fe-N_χ species with excellent catalytic activity and durability. Finally, both fundamental understanding of liquid Zn-air battery with well-ground catalysts powders from carbon fabric and practical application of self-supported carbon fabric electrode in solid-state Zn-air battery exhibit promising performance. Our results strongly suggest that natural cellulose fabrics can be a promising material for fabricating highly active, durable and affordable air cathodes for many renewable energy devices such as metal-air batteries and fuel cells.