Enzymatic synthesis of biocompatible polypyrrole with enhanced electrochemical properties for supercapacitors

This study focuses on the biocompatible and ecofriendly enzymatic synthesis of conductive polypyrrole (PPy) using mediators for supercapacitor electrode material. The work investigates the effects of various mediator systems on laccase-catalyzed oxidation of pyrrole and is confirmed through Fourier transform infrared spectroscopy (FTIR) and Ultraviolet (UV) visible spectroscopy. The x-ray diffraction (XRD) and transmission electron microscopy (TEM) analysis has revealed that both mediators and laccase can produce crystalline and amorphous PPy with agglomeration of globular-shaped particles. The PPy-ABTS (2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonate) demonstrates higher decomposition temperatures, indicating superior thermal stability up to 400 °C. Electrochemical studies such as cyclic voltammetry (CV), galvanometric charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS) revealed that PPy-ABTS possesses good electrochemical properties. Compared to other laccase-mediated materials synthesized PPy in this study, PPy-ABTS exhibits higher specific capacitance values (242 F g−1 by CV at 10 mV s−1 and 153 F g−1 by GCD at 1 A g−1), with a capacitance retention of nearly 90 % after 10000 cycles. Cytotoxicity study shows that PPy-ABTS has an IC50 value of 528 μg ml−1 against human breast adenocarcinoma (MCF-7) cells, indicating its biocompatibility. Consequently, PPy-ABTS emerges as a promising electrode material for high-performance supercapacitors. Its unreported biocompatibility opens up possibilities for diverse biomedical applications.