Sodium cholate orchestrated synthesis of silver deposited camphorsulphonic acid doped rodlike polypyrrole architecture for asymmetric supercapacitor applications

Abstract

An asymmetric supercapacitor (ASC) was developed using camphorsulphonic acid (CSA)-doped polypyrrole (PPY) nanorods as the positive electrode and activated carbon as the negative electrode. The CSA doping and rod-like morphology enhanced the conductivity and electrochemical activity of PPY. Density functional theory (DFT) analysis revealed that CSA significantly lowers the HOMO–LUMO energy gaps of pyrrole oligomers, particularly with increasing chain length, indicating improved electronic properties favorable for charge storage. Electrochemical testing showed that the pristine CSA-doped PPY electrode exhibited a moderate specific capacitance of 180 F g⁻¹ at 2 mV s⁻¹, which decreased at higher scan rates. However, after silver nanoparticle deposition on the PPY surface, it displayed a highly reversible and rectangular-type cyclic voltammetry (CV) profile, indicating ideal capacitive behavior, with a specific capacity of 527.28 F g⁻¹ at a scan rate of 2 mV s⁻¹. This enhancement was attributed to the strong interaction between silver and the CSA-doped PPY nanorods, which synergistically improved the capacitive performance. The energy density value obtained from the Ragone plot was 12.57 Wh kg⁻¹. These findings demonstrated the potential of metal-doped conductive polymers for high-performance supercapacitor applications. For real-time evaluation, cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) tests were performed on the assembled asymmetric supercapacitor (ASC). The ASC employed an Ag-deposited, CSA-doped polypyrrole (PPY) positive electrode and a biowaste-derived activated porous carbon negative electrode. The device delivered a specific capacitance of 208.88 F g⁻¹ at 2 mA cm⁻², with corresponding gravimetric energy and power densities of 41.78 Wh kg⁻¹ and 886.89 W kg⁻¹, respectively.