One-step electrosynthesis of polypyrrole/PbOx composite in acetonitrile as supercapacitor electrode material

This study explores the single step electrochemical synthesis of polypyrrole/PbOx composite on the Pb-intercalated (intc.) graphite electrode in acetonitrile medium, including Py, TBABF4, HBF4, H2O, Pb(BF4)2, TX100 and carboxymethyl cellulose. The coatings on Pb-intc. graphite surface are analyzed by SEM-EDX, BET, TEM, XPS, and XRD techniques. The effects of the additives on the capacitive properties are investigated electrochemically in an H2SO4/water medium. PbOx and carboxymethyl cellulose enhance the specific capacitance and the cyclic stability. Although the amount of PbOx in the composite is low (1.2% atomic percentage of Pb), it contributes significantly to the specific capacitance due to the homogenous distribution of PbOx in nanostructures. The amount of specific capacitance of the composite film (4.0 mg cm−2 loading) on the Pb-intc. pencil graphite is calculated as 377 F.g−1 at 2.0 A.g−1 in 100 mM H2SO4 by subtracting that of bare graphite. The two electrode cells (asymmetric and symmetric) are constructed using Teflon Swagelok in polyvinyl alcohol/H2SO4 gel electrolyte. In the symmetric supercapacitor configuration, the composite coating (10 mg cm-2 loading) on Pb-intc. graphite paper electrode has 0.29 kW kg−1 and 22 Wh. kg−1 at 0.5 A g−1. The results also indicate a good cycle performance (94% after 5000 cycles) in the potential range of 0.8 V.