Hollow Tubular Structure of NiCo2S4/NiFe‐LDH can Function as a Bifunctional Catalyst for Aqueous and Flexible Zinc‐Air Batteries

This work initially prepares 1D hollow rod‐like NiCo2S4 nanomaterials using the solvothermal method, and subsequently grew NiFe‐ layered double hydroxide (LDH) nanosheets on their surface, thereby obtaining NiCo2S4/NiFe‐LDH composite materials. The uniform dispersion and growth of the sheet‐like NiFe‐LDH on the surface of the NiCo2S4 nanorods effectively maintained structural stability during the catalytic process, thus achieving efficient and stable catalytic performance. Additionally, the hollow NiCo2S4 nanorods maximize the exposure of active sites, thereby exhibiting excellent oxygen reduction reaction (ORR) performance. Meanwhile, the sheet‐like NiFe‐LDH grown on the surface of the NiCo2S4 nanorods demonstrates excellent oxygen evolution reaction (OER) activity. Furthermore, NiCo2S4/NiFe‐LDH exhibits excellent bifunctional catalytic activity for both ORR and OER (ΔE = 0.75 V). The overpotential of the OER is 320mv and the half‐wave potential of the ORR is 0.80 V. The catalyst was used as a cathode material for zinc‐air batteries. When tested at a current density of 3 mA cm−2, the charge/discharge cycle can be stabilized for ≈450 h. When tested at a current density of 5 mA cm−2, the battery was able to maintain stable charge/discharge cycling for ≈350 h.