1D/2D hierarchical Co1-xFexO@N-doped carbon nanostructures for flexible zinc–air batteries

Flexible zinc–air batteries (ZABs) are capable of powering the wearable electronic devices due to its high energy density and low cost. However, the sluggish oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) of the cathode materials greatly impede the practical application of ZABs. Here, we propose a synthetic strategy to prepare a unique 1D/2D hierarchical Co1-xFexO@NC nanostructures grown on flexible carbon cloth (Co1-xFexO@NC/CC), featuring enhanced OER and ORR reaction kinetics. The unique architecture is obtained from 1D Co1-xFex carbonate hydroxide hydrate nanowires grafted with 2D Co1-xFex-ZIF (ZIF = zeolitic imidazolate framework) nanosheets. For OER, the overpotential of Co0.68Fe0.32O@NC/CC is 260 mV. The half-wave potential of Co0.68Fe0.32O@NC/CC is 0.81 V for ORR. Moreover, the voltage gap is only 0.68 V. The assembled Co0.68Fe0.32O@NC/CC-based flexible ZABs exhibits a high open-circuit potential of 1.300 V, a high specific capacity of 673 mAh gZn−1, excellent cycling stability and outstanding flexibility, overwhelming the state-of-the-art Pt/C-based ZABs. The work will open up a new avenue for the development of the practical application of ZABs in wearable electronic devices.