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 NiCo 2 S 4 nanomaterials using the solvothermal method, and subsequently grew NiFe‐ layered double hydroxide (LDH) nanosheets on their surface, thereby obtaining NiCo 2 S 4 /NiFe‐LDH composite materials. The uniform dispersion and growth of the sheet‐like NiFe‐LDH on the surface of the NiCo 2 S 4 nanorods effectively maintained structural stability during the catalytic process, thus achieving efficient and stable catalytic performance. Additionally, the hollow NiCo 2 S 4 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 NiCo 2 S 4 nanorods demonstrates excellent oxygen evolution reaction (OER) activity. Furthermore, NiCo 2 S 4 /NiFe‐LDH exhibits excellent bifunctional catalytic activity for both ORR and OER (Δ E = 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.