Electrochemical Behavior of a Hybrid Nanocomposite Based on Poly(3,6-di(3-aminophenyl)amino-2,5-dichloro-1,4-benzoquinone and Single-Walled Carbon Nanotubes on Graphite Foil in a Lithium Aprotic Electrolyte

Resumo

Hybrid nanocomposites based on poly(3,6-di(3-aminophenyl)amino-2,5-dichloro-1,4-benzoquinone) and single-walled carbon nanotubes were obtained under monomer polymerization conditions in concentrated formic acid under the action of benzoyl peroxide in the presence of single-walled carbon nanotubes. The electrochemical behavior in an aprotic lithium electrolyte of composite electrodes having the form of strips of anodized graphite foil having on its surface an active layer of a stable suspension of the nanocomposite in formic acid was examined in the absence of any binding and electrically conducting additives. The specific electrochemical capacitance of the coating reaches a value of 500 F g⁻¹ at a charge-discharge current of 1.5 mA cm⁻² in an inorganic electrolyte composed of 1 M LiClO₄ in propylene carbonate. It was found that the Faraday pseudo-capacitance makes an insignificant contribution to the electrochemical capacitance of composite electrodes, which is mostly determined by the charging of an electric double layer. The nanocomposite coatings are characterized by high stability of their electrochemical characteristics at a coulomb efficiency of 97–100%. The fall of the capacitance upon prolonged cycling (>300 cycles) does not exceed 4%. The electrochemical characteristics of electrodes on friable substrates of anodized graphite foil strongly surpass those for electrodes obtained on nickel or rolled graphite foil as substrates.