Supercapacitive properties of electrodeposited polyaniline electrode in acrylic gel polymer electrolytes

• Polyaniline electrode is electrodeposited and its supercapacitive properties are characterized in acrylic gel polymer electrolytes.
• The supercapacitor exhibits higher capacitance at high scan rates due to interaction between the H2SO4 and acrylic polymers.
• The acrylic gel polymer electrolytes enhance the long-term stability of polyaniline supercapacitors.

Polyaniline (PAn) electrode for a supercapacitor is prepared by electrodepositing on a platinum substrate. Its supercapacitive properties are characterized after adopting acrylic gel polymer electrolytes, such as poly(acrylic acid) (PAA), potassium polyacrylate (PAAK), and poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPS). The electrodeposited PAn (ePAn) exhibits a network structure compactly connected with particles or particle aggregates to yield a porous morphology with an average pore size of 4 μm. The cyclic voltammogram of the ePAn electrode shows redox pair peaks on both cathodic (around 0.2 V) and anodic scans (around 0.1 V vs. Ag/AgCl) at low scan rates, but the redox peak potentials shift to give a higher potential difference at high scan rates, implying higher polarization. Except for the H2O/PAMPS electrolyte, the ePAn supercapacitor that adopts the acrylic gel polymer electrolytes exhibits comparable specific capacitance of 400–500 F g−1, even at high scan rates, due to specific interactions between the H2SO4 solvent molecules and acrylic polymers.