Interface Engineering of CoO/N-Doped Carbon Nanomaterials as a Bifunctional Electrocatalyst for Rechargeable Zinc-Air Batteries

Robust bifunctional and highly efficient electrocatalysts for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) exhibits great prospect in a zinc-air battery (ZAB). Here, we demonstrated a facile route to synthesize a bifunctional electrocatalyst with CoO nanoparticles embedded in N-doped carbon by interface engineering. The precursor which consists of ball-milled polyaniline (BM-PANI), carbon nanotubes (CNTs) and cobalt acetate tetrahydrate (Co(Ac)2·4H2O) was obtained via homogeneous mixture in the presence of ethanol, and thus, satisfactory interface was formed. After calcination, the synthesized CoO/N-doped carbon composite material presents a half-wave potential of 0.818 V for ORR and an overpotential of 0.417 V at 10 mA cm−2 for OER, which endows it a power density of 92.04 mW cm−2 in a homemade rechargeable ZAB and a high stability outperforming commercial Pt/C. This work highlights the mixture of precursors by interface engineering, thus improving the synergistic effect between metal oxide and carbon and elevating the electrocatalytic activity.