Accelerating Triple Transport in Zinc-Air Batteries and Water Electrolysis by Spatially Confining Co Nanoparticles in Breathable Honeycomb-Like Macroporous N-Doped Carbon

Rational engineering electrode structure to achieve an efficient triple-phase contact line is vital for applications such as in zinc-air batteries and water electrolysis. Herein, a facile MOF-in situ-leaching and confined-growth-MOF strategy is developed to construct a breathable trifunctional electrocatalyst based on N-doped graphitic carbon with Co nanoparticles spatially confined in an inherited honeycomb-like macroporous structure (denoted as Co@HMNC). The unique orderly arranged macroporous channels and the ships in a bottle confinement effect jointly expedite the triple transport, endowing the catalysts with fast reaction kinetics. As a result, the obtained Co@HMNC catalyst presents superb trifunctional performance with a positive half-wave potential (E-1/2) of 0.90 V for oxygen reduction reaction (ORR), and low overpotentials of 318 and 51 mV for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) at 10 mA cm(-2), respectively. The Co@HMNC-based liquid Zn-air battery reaches a large specific capacity of 859 mA h g(Zn)(-1), a high-power density of 198 mW cm(-2), and long-term stability for 375 h, suggesting its promise for actual applications.

Automated summary

The Co@HMNC catalyst, prepared using a strategy of MOF in-situ-leaching and confined-growth-MOF, exhibits excellent tri-functional performance in zinc-air batteries and water electrolysis, with fast reaction kinetics, high stability, and promising potential for practical applications.