Synthesis of confining cobalt nanoparticles within SiOx/nitrogen-doped carbon framework derived from sustainable bamboo leaves as oxygen electrocatalysts for rechargeable Zn-air batteries

Well-dispersed cobalt nanoparticles (NPs) are synthesized on a silicon oxide/nitrogen-doped carbon framework derived from sustainable bamboo leaves through in situ pyrolysis of cobalt silicate/nitrogen-doped carbon. The three-dimensional (3D) transmission electron microscopy (TEM) tomography technique reveals the detailed distribution of Co NPs on the framework. The framework ensures a fine distribution, provides an interconnected conductive network, and improves the catalytic activity and stability of the ternary Co catalysts. Consequently, the optimized CR900 electrocatalyst exhibits superior electrochemical activity, including a low overpotential of 263 mV at 10 mA cm−2 and a half-wave potential of 0.81 V for OER and ORR, respectively. Furthermore, the Zn-air battery with the CR900 catalyst displays a maximum power density of 138.2 mW cm−2 and prominent cycling durability after 400 h. Furthermore, we provide insights into the scalable synthetic strategy of metal or alloy-based catalysts towards high-performance rechargeable metal-air batteries.