Chapter 13 - Carbon Nanotubes as a Novel π-Electron Material and Their Promise for Technological Applications

Abstract

The π-electron materials have extended π-electron clouds in the solid state and have various peculiar properties such as high electron mobility and chemical/biological activities. A set of techniques for synthesizing carbonaceous π-electron materials has been developed, especially crystalline graphite and carbon nanotubes, at temperatures below 1000°C. New types of physical or chemical interactions between π-electron materials and various other materials have been revealed. The unique interactions found in various π-electron materials, especially carbon nanotubes, are helpful for developing novel functional, electronic devices. Physics and chemistry of graphite intercalation compounds (GICs), or the intercalation of carbonaceous π-electron materials in general, have entered upon a new stage of development, partly because new intercalants like alkali metal oxides and various gases are introduced. And partly because they have come to have a very significant technological importance in that the capacity of lithium-ion secondary batteries strongly depends on the nature of carbon electrodes. Various new carbon materials including amorphous carbons starting from polymeric materials and CNTs have been examined as a high-capacity cathode. The CNTs, especially SWCNTs, have found their utility in the area of energy storage technology as in hydrogen storage reservoirs and electrochemical capacitors.