Long-range interconnected nanoporous Co/Ni/C composites as bifunctional electrocatalysts for long-life rechargeable zinc-air batteries

Zinc-air batteries are considered to be a promising candidate for use as a sustainable power source, due to their higher energy density and more economical features. However, it is necessary to design efficient and durable electrocatalysts, especially the durability, for bifunctional oxygen reduction (ORR) and oxygen evolution reactions (OER). Therefore, it is imperative to developing reliable zinc-air batteries with long-lasting cycle lifetime. Herein, we report long-range interconnected nanoporous Co/Ni/C composites in mu m-length scale as highly active and stable bifunctional electrocatalysts for long-life rechargeable zinc-air batteries. The composite catalysts consist of N and S co-doped hollow carbon and carbon-encapsulated CoNi alloy nanoparticles, which serve as catalytically active sites for the ORR/OER. Meanwhile, the long-range interconnected nanoporous carbon structure in mu m-length scale favors fast ion and electron transfer during the reactions, and can prevent the catalyst deterioration against nanoparticles collapse and agglomerate into large ones during the long-term battery operation. As a result, compared to the commercial precious metal-based catalysts, the Co/Ni/C composite catalysts exhibit a significantly improved stability towards the ORR/OER with small activity decay after 100 h/10 h of operation under chronoamperometric polarization. Especially, the resulting zinc-air battery demonstrates remarkable cycling stability exceeding 620 h and 430 h at 5 and 10 mA cm(-2), respective.

Automated summary

This study presents long-range interconnected nanoporous Co/Ni/C composites as highly active and stable bifunctional electrocatalysts for long-life rechargeable zinc-air batteries. The composite catalysts consist of hollow carbon and carbon-encapsulated CoNi alloy nanoparticles, which serve as active sites for the oxygen reduction and oxygen evolution reactions. The interconnected nanoporous carbon structure facilitates fast ion and electron transfer and prevents catalyst deterioration.