Luffa-like Interconnective Porous Nanofiber with Anchored Co/CoCr2O4 Hybrid Nanoparticles for Zinc–Air Batteries

The development of robust oxygen reduction reaction (ORR) catalyst with fast kinetics and good durability is significant for rechargeable zinc–air batteries (ZABs) but still remains a great challenge. Herein, inspired by the chain-like interconnective porous structure of plant luffa, an ORR catalyst of Co/CoCr2O4@ IPCF is fabricated, with Co and CoCr2O4 hybrid nanoparticles (NPs) embedding into interconnective porous carbon nanofibers (IPCF). Contributing to CoCr2O4 NPs stabilized Co active sites, the resulting ZABs assembled with Co/CoCr2O4@IPCF as an air cathode catalyst delivering sustainable cycling stability of 550 h, surpassing that of Co@IPCF based on ZABs (215 h). Also, the Co/CoCr2O4@IPCF has a high ORR performance with a half-wave potential (E1/2) of 0.866 V in alkaline medium. The cycling stability originates from the IPCF carrier and the synergistic effect of Co NPs and CoCr2O4 NPs. The chain-like interconnective porous structure of the fibers provides more active sites and facilitates mass transfer to avoid the accumulation of OH− and the exposure of H2O2, while the CoCr2O4 NPs can serve as a regulator for stabilizing the Co NPs electrochemical performance.