Enhanced oxygen evolution performance of spinel Fe0.1Ni0.9Co2O4/Activated carbon composites

• Published in: Electrochimica acta 2019-12, Vol.326, p.134986, Article 134986
• Main Authors: Lu, Yi-Ting, Wu, Jianyuan, Lin, Zhi-Xiu, You, Ting-Hsuan, Lin, Sheng-Chi, Tiffany Chen, Hsin-Yi, Hardwick, Laurence J., Hu, Chi-Chang
• Format: Article
• Language: English
• Subjects: Activated carbon; Catalytic activity; Charge transfer; Cobalt oxides; Composite materials; Cycles; Cycling stability; Electrocatalysts; Electrochemical impedance spectroscopy; Energy storage; Iron-doped nickel cobalt oxide; Metal air batteries; Oxidation; Oxygen evolution reaction; Oxygen evolution reactions; Rechargeable batteries; Rechargeable zinc-air battery; Rotating disks; Storage systems; Zinc; Zinc-oxygen batteries
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2019.134986

A series of iron-doped nickel cobalt oxide/activated carbon (Fe0.1Ni0.9Co2O4/AC) composites with various ratios of activated carbon were synthesised via a microwave-assisted hydrothermal method. The introduction of activated carbon significantly promotes the catalytic activity of Fe0.1Ni0.9Co2O4 for the oxygen evolution reaction (OER); meanwhile the complete coverage of nanoparticulate Fe0.1Ni0.9Co2O4 onto activated carbon particles prevents the carbon oxidation, leading to improved cycling durability of a zinc-air cell. Scanning electron microscopy images shows a good protective coverage of the nanoparticulate Fe0.1Ni0.9Co2O4 onto the activated carbon particles. Rotating disk electrode voltammetry and electrochemical impedance spectroscopic results reveal that the OER overpotential and charge-transfer resistance of the Fe0.1Ni0.9Co2O4 electrocatalyst are substantially lowered by the introduction of activated carbon. With respect to the cycling stability, Fe0.1Ni0.9Co2O4/1.0 wt%AC and Fe0.1Ni0.9Co2O4/1.5 wt%AC composites maintain excellent activity for 80 h in a rechargeable zinc-air battery, due to the uniformly protective coverage of metal oxide on activated carbon. Furthermore, the Fe0.1Ni0.9Co2O4/3.7 wt%AC composite was examined in a prolonged rechargeable zinc-air battery test for 120 h and the charge-discharge voltage gap was negligibly enlarged (0.02 V increment after 120 h), which showed their potential as electrocatalysts for long-term energy storage systems. The OER activity of Fe0.1Ni0.9Co2O4 is enhanced by the introduction of activated carbon (AC). [Display omitted] •Activated carbon (AC) enhances the O2 evolution reaction activity of Fe0.1Ni0.9Co2O4.•Fe0.1Ni0.9Co2O4 particles cover the AC and prevent carbon corrosion.•The composite shows stable cycling in the 120-h test.•The zinc-air cell shows a power density of 99 mW cm−2 at 100 mA cm−2.