Developing nitrogen and Co/Fe/Ni multi-doped carbon nanotubes as high-performance bifunctional catalyst for rechargeable zinc-air battery

J Colloid Interface Sci. 2021 Jul:593:204-213. doi: 10.1016/j.jcis.2021.02.115. Epub 2021 Mar 9.

Abstract

Rational construction of advanced bifunctional catalysts with dual-active-sites is still challenging for both oxygen reduction (ORR) and oxygen evolution reactions (OER). Herein, metal-doped dicyandiamide formaldehyde resin is innovatively exploited to synthesize N/Co/Fe/Ni multi-doped carbon nanotubes (denoted as CoFeNi@CNT) with metal-nitrogen-carbon (MNC) and CoFeNi nanoparticles as the ORR and OER active sites, respectively. Abundant active sites and high degree of graphitization enable CoFeNi@CNT with a high ORR half-wave potential of 0.82 V and a low OER overpotential of 440 mV at 10 mA cm-2, which are comparable or superior to noble-metal catalysts. Particularly, the CoFeNi@CNT air electrode of rechargeable Zn-air batteries shows remarkable open circuit potential (1.46 V), discharge power density (152.3 mW cm-2), specific capacity (814 mAh g-1), and cycling stability for more than 250 h. It is worth emphasizing that this synthesis strategy is rather simple, low-cost, high yield, and the proportion and amount of doped metal ions can be easily adjusted according to the needs for different applications.

Keywords: Bifunctional catalyst; Carbon nanotubes; Dicyandiamide formaldehyde resin; FeNi nanoparticles; Metal-nitrogen-carbon; Zn-air battery.