Capacitive performance of electrode materials affected by the Cu2O template morphologies in graphene/polyaniline nanotube/ZIF-67 nanocages porous composite

Abstract

Graphene/polyaniline nanotube/ZIF-67 nanocages (G/PANI-NT/Z) composites were successfully prepared in a co-precipitation manner and used as electrode material for supercapacitor application. ZIF-67 nanocages, including cube and hexapod, were designed via a simple and fast one-step Cu₂O template etching route. The properties of the as-synthesized nanoparticles were perused by N₂ adsorption–desorption, X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), and electrochemical manners. In particular, the super-capacitive performance of the synthesized materials was perused by changing the morphology of the nanostructures. Results represent that the as-synthesized ZIF-67 nanocages maintain the shape and size of the Cu₂O templates with a hollow, which depicts various capacitive demeanors. Amongst, the two morphologies, the G/PANI-NT/Z-hexapod (h) composite has a larger specific capacitance of 4400 mF g⁻¹, while G/PANI-NT/Z-cubic (c) has a lower one of 3630 mF g⁻¹ at 10 mA g⁻¹ current density. This is mainly due to the presence of ZIF-67 nanocages with hexapod morphology and a larger surface area of 73.58 m²/g in the G/PANI-NT/Z-h composite, which leads to fast interfacial electron transfer and an increase in the diffusion rate of electrolyte ions for higher power density. This demonstrates G/PANI-NT/Z-h electrode is promising for applications in renewable energy storage.