Enhanced supercapacitor performance with cerium-doped polypyrrole nanofibers

Abstract

The current study assessed the potential use of cerium (Ce)-incorporated polypyrrole (PPy) nanofibers (PPy:Ce) as electrode materials for supercapacitors. Cerium incorporation improved the electrochemical performance of PPy, especially by overcoming limitations in cycling stability and energy storage capacity. The PPy and PPy:Ce nanofibers, synthesized using chemical oxidative polymerization, have been carefully examined using various characterization techniques. Electron Paramagnetic Resonance (EPR) investigations showed that cerium doping increased the density of paramagnetic centers in the PPy structure, improving electrical conductivity and redox activity. Cyclic voltammetry (CV) tests demonstrated that PPy:Ce nanofibers displayed superior electrochemical performance, achieving a specific capacitance of 203 F g⁻¹ and an energy density of 21.3 W h kg⁻¹. Electron microscopy investigations showed that cerium doping increased the diameter of the nanofibers, resulting in a more uniform shape and improved surface roughness. Brunauer–Emmett–Teller (BET) analysis revealed that while cerium doping reduces surface area, it optimizes the pore structure, enhancing ion transport and electrolyte access. This optimization allows for larger pore sizes that facilitate easier ion movement, compensating for the decreased surface area. Structural and electrochemical improvements have been achieved through the homogeneous incorporation of cerium doping into the PPy framework. Cerium doping boosts the cycling stability of PPy, providing an important advantage for long-term energy storage applications. This work presents an alternate method for producing supercapacitor electrodes that demonstrate outstanding efficacy in practical applications utilizing a two-electrode setup. This study significantly contributes to the literature by demonstrating the enhanced performance values achieved by directly incorporating cerium ions into the PPy matrix.