Developing high-performance and low-cost electrocatalysts is key to achieve the clean-energy target. Herein, a dual regulation method is proposed to prepare a 3D honeycomb-like carbon-based catalyst with stable Fe/Co co-dopants. Fe atoms are highly dispersed and fixed to the polymer microsphere, followed by a high-temperature decomposition, for the generation of carbon-based catalyst with a honeycomb-like structure. The as-prepared catalyst contains a large number of Fe/Co nanoparticles (Fe/Co NPs), providing the excellent catalytic activity and durability in oxygen reduction reaction, oxygen evolution reaction and hydrogen evolution reaction. The Zn-air battery assembled by the as-prepared catalyst as air cathode shows a good charge and discharge capacity, and it exhibits an ultra-long service life by maintaining a stable charge and discharge platform for a 311-h cycle. Further X-ray absorption fine structure characterization and density functional theory calculation confirms that the Fe doping optimizes the intermediate adsorption process and electron transfer of Co.

Although the Zn-air battery has many advantages, its short practical life hinders its development. Many solutions have been proposed and extensively studied. In this paper, a cobalt-nitrogen co-doped hierarchical porous carbon-based bifunctional catalyst (Co/N-HPCs-800) is reported, using sustainable and low-cost sodium alginate (Na-Alg), a common seaweed extract, as a precursor to complex excess metal particles. The hydrogel network formed by the exchange of sodium ions with metal cation (Co 2+ ) ions is the key to the controllable synthesis of highly dispersed metal atoms. Co/N-HPCs-800 shows excellent catalytic performance and durability in oxygen reduction reaction (E 1/2 = 0.86 V) and oxygen evolution reaction (367 mV @ 10 mA cm −2 ). Importantly, we only attenuated the half-wave potential by 8 mV after more than 50,000 cycles. In addition, the Zn-air batteries (ZABs) using Co/N-HPCs-800 as a cathode exhibit a power density up to 159.67 mW cm −2 and a high specific capacity of 787.94 mA h g −1 . This work opens up practical new strategies for synthesizing excess metal catalysts in low cost, effectively improving the service life of Zn-air batteries.

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