Nickel-iron layered double hydroxides interlinked by N-doped carbon network as bifunctional electrocatalysts for rechargeable zinc-air batteries

Abstract

The rational design and fabrication of electrocatalysts with low cost and excellent bifunctional properties for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are desirable for high-efficiency rechargeable zinc-air batteries. Herein, we report the synthesis of NiFe LDHs nanoparticles interconnected by the one-dimensional N-doped carbon nanotubes (CNTs) and two-dimensional graphene nanosheets (NiFe-CNTs-rGO). The in-situ formed N-doped carbon and Fe-N-C active sites highly improve the ORR activity and the loading of NiFe LDHs nanoparticles promotes the OER. The integration of NiFe LDHs with intertwined CNTs and netlike rGO guarantees the good electrical conductivity of NiFe-CNTs-rGO. The unique composition and microstructure endow NiFe-CNTs-rGO with superior bifunctional activity toward ORR and OER. Moreover, the rechargeable zinc-air battery assembled with NiFe-CNTs-rGO electrocatalyst as air cathode shows a high capacity of 793 mA h g−1 and works stable for 100 h at 10 mA cm−2, outperforming commercial Pt/C and RuO2 mixture.