A thermal evaporation-trapping strategy to synthesize flexible and robust oxygen electrocatalysts for rechargeable zinc-air batteries

• Published in: Energy & environmental science Vol. 17; no. 23; pp. 9375 - 9382
• Main Authors: Zhang, Hong-Bo, Meng, Yu, Fang, Lingzhe, Yang, Fei, Zhu, Shangqian, Li, Tao, Yu, Xiaohua, Rong, Ju, Chen, Weiwei, Su, Dong, Mei, Yi, Hou, Peng-Xiang, Liu, Chang, Shao, Minhua, Li, Jin-Cheng
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 26.11.2024
• Subjects: Carbon fibers; Chemical synthesis; Cobalt ferrites; Downsizing; Electrocatalysts; Evaporation; Intermetallic compounds; Iron; Metal air batteries; Nanoparticles; Oxygen; Raman spectroscopy; Trapping; Zinc-oxygen batteries
• ISSN: 1754-5692; 1754-5706
• DOI: 10.1039/d4ee03005b

Great efforts have been devoted to the development of bifunctional electrocatalysts to accelerate the sluggish kinetics of cathodic oxygen reduction/evolution reactions (ORR/OER) in zinc-air batteries (ZABs). Here we report a thermal evaporation-trapping synergistic strategy to fabricate a bifunctional electrocatalyst of flexible N-doped carbon fiber cloth loaded with both CoFe-oxide nanoparticles and single-atom Co/Fe-N x sites, in which the thermal evaporation process functions in both downsizing CoFe-oxide nanoparticles and trapping the evaporated Co/Fe species to generate Co/Fe-N x sites. The obtained flexible electrocatalyst, directly serving as an oxygen electrode, displays a small potential gap of 0.542 V for the OER/ORR, large peak power densities (liquid-state ZAB: 237.4 mW cm −2 ; solid-state ZAB: 141.1 mW cm −2 ), and excellent charge-discharge cycling stability without decay after working more than 770 hours. Furthermore, in situ Raman spectroscopy characterization and theoretical calculations reveal that CoFe 2 O 4 species is responsible for the OER while atomic Fe/Co sites play a key role in the ORR. A thermal evaporation-trapping strategy is developed to fabricate a flexible N-doped carbon fiber cloth loaded with both CoFe-oxide nanoparticles and atomic Co/Fe-N x sites, showing outstanding oxygen electrocatalytic performance.