Application of Nanocarbons Modified with Anthraquinone Polycondensation Polymer to Electrochemical Double Layer Capacitance

Carbon-based fine particles have been widely used as fillers for enhancing the reinforcement for bulk materials. In addition, the excellent physical stability and unique chemical properties of these fine particles expand their potential utility in electroconductive materials, carriers for catalysis, packing materials such as pigment and colorant for inks, paints, and resins. Recently, it was reported that one-pot polymerization of 1.5-dihydoroxynaphtalene (DHN) and 1,3,5-1,3,5-trimethyl-1,3,5-triazinane(TA) in ethanol or other related solvents without any additives, and subsequent calcination at relatively enables us to control the diameter of the resultant particle in the range of submicron to a couple of microns. In this study we report that the nano carbons modified with an anthraquinone polycondensation polymer prepared by this one-pot polymerization method using an aromatic hydrocarbon with OH groups and TA function as an electrochemical double layer capacitors (EDLC). Anthraquinone derivatives having two OH groups and 1,3,5-trimethyl-1,3,5-triazinane (TA) were purchased from Tokyo Chemical Industry Co., Ltd. and used as received. Carbon black powders (DENKA Black) and mineral oil were purchased from DENKA Co. Ltd. and Sigma, respectively. Cyclic voltammetry (CV) and potential step chronocoulometry were performed with a ALS model 621 electrochemical analyzer. A platinum plate and Ag/AgCl (KCl sat.) were used as a counter and reference electrode, respectively. CV in 0.1 M HClO4 at a bare carbon black (CB) electrode shows very small charging current without redox waves. In contrast, at the CB modified with anthraquinone condensation polymer (AQP), redox waves of anthraquinone moieties associated with a large charging current. The capacitance calculated from CV depended on the kind and concentration of the supporting electrolyte used, the kind of carbon black, and modification conditions of the AQP. The capacitance of 1.34 F cm-2 was obtained at the AQP modified CB (DENKA Black HS-100) in 0.1 M HClO4. This modification method is very simple, versatile, and effective for modifying nanocarbons.