The large-scale fabrication of highly efficient and low-cost bifunctional catalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is critical to the development of rechargeable zinc-air batteries (ZABs).… Click to show full abstract
The large-scale fabrication of highly efficient and low-cost bifunctional catalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is critical to the development of rechargeable zinc-air batteries (ZABs). Herein, a scalable dealloying strategy is proposed to obtain hierarchically porous spinel-type oxide with minor hereditary Al doping. Benefiting from the well-structured porosity and native dopant, O-np-Ni5Co10(Al), namely Al-NiCo2O4, exhibits excellent electrocatalytic ORR and OER activities, giving a small potential gap of 0.71 V. Meaningfully, the rechargeable ZAB with O-np-Ni5Co10(Al) as cathode catalyst delivers a high specific capacity of 757 mAh g-1, a competitive peak power density of 142 mW cm-2 and a long-term discharge-charge cycling stability. Furthermore, density functional theory (DFT) calculations evidence that appropriate Al doping into NiCo2O4 could significantly reduce the Gibbs free energy (ΔG) difference to 1.71 eV. This work is expected to inspire the design of performance-oriented bifuntional electrocatalysts for wider application in renewable energy systems.
               
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