Interfacial engineering Co and MnO within N,S co-doped carbon hierarchical branched superstructures toward high-efficiency electrocatalytic oxygen reduction for robust Zn-air batteries

Electronic regulation via interfacial formation is identified as a versatile strategy to improve the electrocatalytic activity. Herein, we report a feasible electrospinning-pyrolysis approach for the in-situ immobilization of Co/ MnO hetero-nanoparticles onto N,S co-doped carbon nanotubes/nanofiber-integrated hierarchical branched superstructures (abbreviated as Co/MnO@N,S-C NT/CNFs hereafter). The simultaneous realization of interfacial engineering and nanocarbon hybridization renders the fabricated Co/MnO@N,S-C NT/CNFs with abundant firmly anchored active sites, modified electronic configuration, improved electric conductivity, efficient mass transport pathways, and significantly reinforced stability. Profiting from the compositional synergy and architectural advantages, the Co/MnO@N,S-C NT/CNFs exhibit outstanding ORR activity, superior tolerance to methanol, and excellent long-term stability in KOH electrolyte. More encouragingly, as a proof-of-concept demonstration, the rechargeable aqueous and flexible all-solid-state Zn-air batteries using Co/MnO@N,S-C NT/NFs + RuO2 as the air-cathode afford higher power densities, larger specific capacities and superb cycling stability, outperforming the state-of-the-art Pt/C + RuO2 counterparts. This work demonstrates the great contribution of heterointerfaces for oxygen electrocatalysis.

Automated summary

The electrospinning-pyrolysis method immobilizes Co/MnO hetero-nanoparticles onto N,S co-doped carbon nanotubes/nanofiber-integrated superstructures, resulting in abundant active sites, modified electronic configuration, improved conductivity, efficient mass transport pathways, and significantly enhanced stability. The Co/MnO@N,S-C NT/CNFs show outstanding ORR activity, superior methanol tolerance, and excellent long-term stability in KOH electrolyte.