Electrochemical Capacitance of Nanocomposite Polypyrrole/Cellulose Films

Porous nanocomposites consisting of cellulose nanocrystals (CNXLs) and polypyrrole (PPY) were fabricated using electrochemical co-deposition. The CNXLs were extracted from cotton using sulfuric acid hydrolysis and were subjected to 2,2,6,6-tetramethylpiperidine-1-oxyl-mediated oxidation, in which primary hydroxyls were oxidized to carboxylate moieties. The PPY/CNXL composites were electrodeposited from a solution of the carboxylated CNXLs and pyrrole (PY) monomers, and the negatively charged CNXLs were incorporated as the counteranion during electrodeposition. The resulting PPY/CNXL nanocomposites were characterized using scanning electron microscopy, cyclic voltammetry, and electrochemical impedance spectroscopy (EIS). Cyclic voltammetry and EIS analysis of the PPY/CNXL nanocomposites showed that the stability and specific capacitance of the nanocomposite material were higher than that of PPY containing Cl− anions. The electrochemical performance of the PPY/CNXL nanocomposites was also compared to that of a PPY/carbon nanotube (CNT) composite deposited under the same conditions, which revealed that the PPY/CNXL nanocomposites had a capacitance similar to that of the PPY/CNT nanocomposite and was at least equally as stable as the PPY/CNT nanocomposite.