Biomass-derived cobalt/carbon hierarchically structured composites for efficient oxygen electrocatalysis and zinc-air batteries

Rechargeable zinc-air batteries with low-cost and highly active bifunctional electrocatalysts have aroused extensive research interests. Herein, a hierarchically structured electrocatalyst was synthesized from biological waste (bovine serum albumin, BSA), integrating encapsulated Co nanoparticles and Co-N-C moieties. The obtained electrocatalysts exhibited superior activities for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), providing a small potential gap (Delta E) of 0.74 V between the ORR half-wave potential and the OER potential at 10 mA cm(-2). Furthermore, the aqueous and flexible quasi-solid-state zinc-air batteries assembled with these hierarchically structured composites demonstrated excellent electrochemical performance with maximum power densities of 173.7 mW cm(-2) and 79.6 mW cm(-2), as well as long-term cycling stability. This integrated strategy opens up an effective way for the development of novel nanostructured electrocatalysts from biological waste.

Automated summary

This study successfully synthesized a hierarchically structured electrocatalyst from biological waste, which exhibited superior activity for both oxygen reduction and oxygen evolution reactions. The zinc-air batteries assembled with this catalyst showed excellent electrochemical performance and long-term cycling stability. This integrated strategy provides an effective way for the development of novel nanostructured electrocatalysts from biological waste.