CoP nanoparticles embedded in three-dimensional porous network-like structured N, O co-doped carbon nanofibers as an effective bi-functional electrocatalyst for rechargeable zinc-air batteries

The development of noble metal-free bi-functional electrocatalysts is consistent with the current concept of sustainable development of energy systems. In this study, we develop a strategy to prepare ZIF-67-derived CoP nanoparticles embedded in three-dimensional porous network-like structured N, O co-doped carbon nanofibers (CoP@N, O co-doped PCNFs) through the processes of electro-blown spinning, carbonization, and in situ phosphorization. And they are regarded as an ORR/OER bi-functional electrocatalyst, which is applied in rechargeable zinc-air batteries. The hierarchically porous structure of the carbon nanofibers facilitates the diffusion of dissolved oxygen and the formation of abundant gas-liquid-solid interfaces in the liquid electrolyte, leading to enhanced ORR/OER activity. Therefore, the ORR half-wave potential of the CoP@N, O co-doped PCNFs reached 0.81 V. In particular, the OER overpotential exhibited 250 mV at 10 mA cm(-2). More importantly, the zinc-air battery constructed with the CoP@N, O co-doped PCNF catalyst has a high specific capacity (797.2 mA h g(-1)) and energy density (927.9 W h kg(-1)) at a current density of 10 mA cm(-2) and can stably cycle for 500 h at a current density of 2 mA cm(-2). The findings will provide a new paradigm for designing more practical noble metal-free bi-functional electrocatalysts for rechargeable zinc-air batteries.

Automated summary

The study developed a strategy to prepare CoP nanoparticles embedded in three-dimensional porous network-like structured N, O co-doped carbon nanofibers. The resulting material showed enhanced ORR/OER activity and was used as a bi-functional electrocatalyst in rechargeable zinc-air batteries. The zinc-air battery with the CoP@N, O co-doped PCNF catalyst exhibited high specific capacity and energy density, and stable cycling performance.