Electrochemical behavior of novel electrode materials based on polydiphenylamine-2-carboxylic acid (PDPAC) binary and ternary nanocomposite coatings was studied for the first time. Nanocomposite materials were obtained in acidic or alkaline media using oxidative polymerization of diphenylamine-2-carboxylic acid (DPAC) in the presence of activated IR-pyrolyzed polyacrylonitrile (IR-PAN-a) only or IR-PAN-a and single-walled carbon nanotubes (SWCNT). Hybrid electrodes are electroactive layers of stable suspensions of IR-PAN-a/PDPAC and IR-PAN-a/SWCNT/PDPAC nanocomposites in formic acid (FA) formed on the flexible strips of anodized graphite foil (AGF). Specific capacitances of electrodes depend on the method for the production of electroactive coatings. Electrodes specific surface capacitances Csreach 0.129 and 0.161 F∙cm−2for AGF/IR-PAN-a/PDPACacand AGF/IR-PAN-a/SWCNT/PDPACac, while for AGF/IR-PAN-a/PDPACalkand AGF/IR-PAN-a/SWCNT/PDPACalkCsamount to 0.135 and 0.151 F∙cm−2. Specific weight capacitances Cwof electrodes with ternary coatings reach 394, 283, 180 F∙g−1(AGF/IR-PAN-a/SWCNT/PDPACac) and 361, 239, 142 F∙g−1(AGF/IR-PAN-a/SWCNT/PDPACalk) at 0.5, 1.5, 3.0 mA·cm−2in an aprotic electrolyte. Such hybrid electrodes with electroactive nanocomposite coatings are promising as a cathode material for SCs.