Flexible, Porous, and Metal-Heteroatom-Doped Carbon Nanofibers as Efficient ORR Electrocatalysts for Zn-Air Battery

HighlightsDoping and porosity generation were completed simultaneously.Metal-heteroatom-doped carbon nanofibers are flexible, porous, and well dispersed.Results include excellent oxygen reduction reaction and enhanced Zn-air battery performance. AbstractDeveloping an efficient and durable oxygen reduction electrocatalyst is critical for clean-energy technology, such as fuel cells and metal-air batteries. In this study, we developed a facile strategy for the preparation of flexible, porous, and well-dispersed metal-heteroatom-doped carbon nanofibers by direct carbonization of electrospun Zn/Co-ZIFs/PAN nanofibers (Zn/Co-ZIFs/PAN). The obtained Zn/Co and N co-doped porous carbon nanofibers carbonized at 800 degrees C (Zn/Co-N@PCNFs-800) presented agood flexibility, a continuous porous structure, and asuperior oxygen reduction reaction (ORR) catalytic activity to that of commercial 20wt% Pt/C, in terms of its onset potential (0.98V vs. RHE), half-wave potential (0.89V vs. RHE), and limiting current density (-5.26mAcm(-2)). In addition, we tested the suitability and durability of Zn/Co-N@PCNFs-800 as the oxygen cathode for a rechargeable Zn-air battery. The prepared Zn-air batteries exhibited ahigher power density (83.5mWcm(-2)), ahigher specific capacity (640.3mAhg(-1)), anexcellent reversibility, and abetter cycling life than the commercial 20wt% Pt/C+RuO2 catalysts. This design strategy of flexible porous non-precious metal-doped ORR electrocatalysts obtained from electrospun ZIFs/polymer nanofibers could be extended to fabricate other novel, stable, and easy-to-use multi-functional electrocatalysts for clean-energy technology.