Functionalized polyethersulfone–CoFe2O4 as electrode material for high-performance supercapacitor

Polyethersulfone (PES), widely used in the separation membrane industry, generates significant waste, presenting an opportunity for repurposing into high-performance supercapacitor electrode materials. This study explores the synthesis of carbon materials with nitrogen-containing functional groups using amine-functionalized polyethersulfone (P-NH₂) as a precursor. These amine groups enabled the binding of cobalt ferrite (CoFe₂O₄), which was produced using D-glucose in a sol-gel method. The resulting composite material, P-NH₂-MO, was subsequently calcined at 200 °C. Various mass ratios of the composite, specifically 1:1, 1:2, and 1:3 (P-NH₂: CoFe₂O₄), were drop-cast onto a current collector. Among these, the 1:2 mass ratio sample exhibited the highest performance, with a specific capacitance of 241 F/g at a current density of 0.5 A/g, surpassing other ratios in electrochemical performance and stability. This sample, labeled P-NH₂-MO-2, also maintained excellent rate performance, retaining 84.21% of its capacitance after 2500 cycles and 78.94% after 5000 cycles at increased current densities (up to 5 A/g). These findings highlight P-NH₂-MO-2 as a promising material for energy storage applications, offering excellent electrochemical performance and long-term stability. • Amine-functionalized polyethersulfone (P) was used as functional carbon materials. • Amine groups bind cobalt ferrite (CoFe₂O₄), which was synthesized via the sol-gel method. • A high specific capacitance was obtained along with long-term cycle life.