Electrophoretic co-deposition of Bi2O3–multiwalled carbon nanotubes coating as supercapacitor electrode

Nafion is suggested as an efficient assistant in preparing supercapacitor by employing nanoparticles. In this work, using a bi-additive of 0.10-mM NaOH + 0.10 g L −1 Nafion, Nafion-assisted electrophoretic co-deposition of Bi 2 O 3 –multiwalled carbon nanotubes (MWCNTs) coating is successfully realized in ethanol solvent. The capacitance performances of the electrophoretic coatings in 6.0-M KOH electrolyte are investigated by cyclic voltammetry and galvanostatic charge–discharge techniques. Comparing with Bi 2 O 3 coating prepared with electrophoretic deposition (EPD) by employing other additive (such as polyethyleneimine), the Bi 2 O 3 coating prepared by Nafion-assisted EPD shows a better capacitance performance. Benefiting from the improvement in coating conductivity caused by MWCNTs, with a small additional amount of 4.0 wt.%, the Bi 2 O 3 –MWCNTs coating exhibits an amazing 164% increase of mass-specific capacitance (473 F g −1 at the current density of 1.0 A g −1 ) in comparison with pure Bi 2 O 3 coating (179 F g −1 at the current density of 1.0 A g −1 ). The cyclic stability test exhibits excellent capacitance retention of 88.7% over 3000 cycles at a constant current density of 10.0 A g −1 . This work combines the advantages of MWCNTs, Nafion, and EPD to provide a facile route for preparing Bi 2 O 3 -based coating as a high-performance supercapacitor electrode.