N-Doped carbon supported Co3O4 nanoparticles as an advanced electrocatalyst for the oxygen reduction reaction in Al–air batteries

Abstract

Low-cost and high-performance catalysts are highly desirable for the oxygen reduction reaction (ORR) in metal–air batteries. Herein, a Co₃O₄/N-doped Ketjenblack (Co₃O₄/N-KB) composite is proposed as a high performance catalyst for Al–air batteries. The synergistic effect between Co₃O₄ and N-KB enables the Co₃O₄/N-KB composite to have a much higher cathodic current, a much more positive half-wave potential and more electron transfer in comparison with Co₃O₄ or N-KB alone. The Co₃O₄/N-KB composite favors a direct four electron pathway in the ORR process, and its ORR current density even outperforms the commercial Pt/C (20 wt%). Al–air batteries using the as-prepared catalyst in the air electrode were constructed, which displayed a high discharge voltage plateau of ∼1.52 V, comparable to that of the commercial Pt/C. The developed Co₃O₄/N-KB composite here could meet the requirements of large-scale application of metal–air batteries due to the much cheaper cobalt source and more economically commercialized carbon source compared to the commercial Pt/C.