Structural Analysis of Carbon Materials with Low Crystallinity

Abstract

This review focuses on the structure of carbon materials with low crystallinity, especially ones prepared at relatively low temperature (500-1000°C). The category includes chars, cokes, and activated carbons, some of which are very attractive considering their future applications to the energy storage. Aside from non-carbon atoms such as hydrogen, oxygen, nitrogen, etc., these types of carbon materials are composed of small aromatic layers, partly surrounded with sp3 hybridized carbon atoms. The aromatic layers are present as a single or stacking layers, often playing important roles for formation of pores. These facts complicate the structure of such carbon materials from the viewpoint of chemical bonding, basic structure, micro-and macro-texture. Actually, experimental results for characterization of carbon materials with low crystallinity do not show distinct features in many cases. Structural information obtained by analyzing the experimental results therefore tends to be still unclear. On the other hand, some recent topics show the availability of new techniques for the quantitative structural characterization, followed by submission of model or detailed description on it. Also, combination of appropriate measurements is effective to cover the unclearness of each measurement. Here, characterization results carried out in our laboratory are shown as examples.