“Setaria viridis”-like cobalt complex derived Co/N-doped carbon nanotubes as efficient ORR/OER electrocatalysts for long-life rechargeable Zn–air batteries

The development of efficient and facile strategies to prepare metal and nitrogen codoped carbon (M-N-C) materials as oxygen electrocatalysts in rechargeable Zn-air batteries with high performance and a long life is challenging. Herein, we report a simple route to synthesize cobalt and nitrogen codoped carbon nanotubes (denoted as Co/N-CNT) as bifunctional oxygen electrocatalysts for rechargeable Zn-air batteries (ZABs). The Co/N-CNT are fabricated through the surface modification of carbon nanotubes with cobalt salt and melamine followed by pyrolysis, which delivers outstanding oxygen reduction/evolution reaction (ORR/OER) activity with a low overall potential gap (ΔE = 0.77 V) and remarkable durability. The home-made Zn-air batteries exhibit a high power density (130 mW cm-2vs. 82 mW cm-2), a large specific capacity of (864 mA h g-1Znvs. 785 mA h g-1Zn), and a long cycling life (1200 h vs. 60 h) in both aqueous and solid media. This work opens an avenue for the reasonable surface modification of carbon nanotubes with various metals and heteroatoms to achieve high-performance electrocatalysts for clean and sustainable energy conversion and storage devices.