Self‐Assembled 3D N/P/S‐Tridoped Carbon Nanoflower with Highly Branched Carbon Nanotubes as Efficient Bifunctional Oxygen Electrocatalyst Toward High‐Performance Rechargeable Zn‐Air Batteries

Abstract

AbstractHeteroatom doping and 3D nanostructures with large specific surface area and hierarchical porous structure can synergically improve oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). In this study, the 3D N/P/S‐tridoped nanoflower with highly branched carbon nanotubes bifunctional catalyst (Co/SP‐NC) is prepared by a simple self‐assembly pyrolysis method. The powerful driving force of coordination interaction of ammonium ion can promote the self‐assembly of 2D ZnCo‐ZIF nanosheets into 3D ZnCo/S‐ZIF nanoflowers at room temperature stirring. The 3D ZnCo/S‐ZIF nanoflower surface is driven by sodium hypophosphite to form highly branched carbon nanotubes during the pyrolysis process. Moreover, Density functional theory (DFT) calculations also confirm that the simultaneous introduction of N/P/S can promote the redistribution of electron density at the catalyst interface. The proper P‐doping not only enhances the electronic conductivity of the substrate, but also facilitates the charge transfer in the OER/ORR process. Therefore, Co/SP‐NC cathode assembled zinc‐air batteries (ZABs) have a higher power density (187 mW cm−2), a larger specific capacity (801 mAh gZn−1) and excellent cycle stability compared to Pt/C‐RuO2 assembled ZABs. This work will pave the way to regulate the components interactions by designing 3D hierarchical porous structures.