Novel glycerol assisted synthesis of polypyrrole nanospheres and its electrochemical properties

Stabilizer free polypyrrole nanospheres were synthesized in glycerol medium and used as an electrode material to study its electrochemical behavior. The synthesis of polypyrrole (PPy) was initiated via the oxidation of pyrrole by ferric chloride in glycerol medium in presence of sodium para-toluene sulfonate. Polymerization of pyrrole in glycerol (GPPY) were carried out at 0 °C and 50 °C, and with or without stirring affecting the morphology, pore size distribution and electrochemical behavior. At 0 °C under stirring a nearly uniform dispersion of polypyrrole nanospheres with a diameter of around 60 nm is obtained, which is about 6 times smaller than conventional polypyrrole (CPPY) synthesized in water. We suggest that the glycerol plays a key role in tailoring the nanostructures of polypyrrole during the polymerization, as a solvent medium which controls the polypyrrole particles size as a stabilizer. Mesopores with pores size between 20 and 80 nm and macropores (>80 nm) have been found more numerous in GPPY than in CPPY synthesized at 0 °C under stirring. The electrochemical behavior and charge storage performances of nanosized polypyrrole (GPPY) was studied in propylene carbonate 1 M tetraethylammonium tetrafluoroborate (Et4NBF4) solution and showed specific capacitance of 200.3 F g−1 for GPPY synthesized at 0 °C under stirring, while CPPY synthesized in water at 0 °C under stirring exhibits a specific capacitance of 151.0 F g−1.