Masafumi Uota

Plasma Surface Treatment of Carbonaceous Materials for Application in Electric Double Layer Capacitors

In this work, carbonaceous materials were modified in order to improve capacitance and charge density in electric double layer capacitors (EDLCs). Optimal conditions for plasma surface treatment of activated carbon have been examined for times from 1 to 10 h at 150 °C. The plasma is a high-frequency glow discharge in N2. The pressure of the gas is 13.3 Pa. The electrode is set up so that the EDLC sample is covered with the glow discharge. Specific capacitance and charge density can be improved by plasma surface treatment of carbon materials.

Synthesis of phenol/furfural polymer nanotubes

The first synthesis of phenol-furfural polymer nanotubes of 2–3nm hollow diameter is demonstrated as well as those with a hexagonal mesostructure. These nanopolymers were obtained by the templating method using a two-step reaction. At the first step, phenol and furfural were moderately reacted into cooligomers in the presence of NaOH. The resulting cooligomeric species were fully anionized and then reacted with additional phenol and alkyl trimetyl ammonium bromide at 40-80°C. The major phase for the 80°C product obtained at low concentration of surfactant was identified as nanotubular polymers of 1.9-3 nm inside and 6 nm outside diameters depending on the chain length of surfactant. In contrast, hexagonal mesostructured polymers characterized by a definite XRD peak occurred preferentially in the reaction using high surfactant-concentrations.