カーボンエアロゲルの巨視的形態の制御による高機能化

抄録

Carbon aerogels are promising materials for the electrodes in electric double-layer capacitors, catalyst supports, and adsorbents because they are monolithic and have a high mesoporosity, high electric conductivity, and excellent chemical stability. The most representative carbon aerogels are obtained by carbonizing resorcinol-formaldehyde (RF) aerogels derived from the sol-gel reaction of RF aqueous solutions and supercritical drying with carbon dioxide. Since these aerogels are neither fusible nor soluble, the macroscopic shape of the carbon aerogels can be controlled only during the sol-gel reaction. The reaction, which requires long-term heating, should be conducted in a closed container to suppress the evaporation of water. Large blocks of RF wet gels can be easily recovered from closed containers, which is why most prior work has been on carbon aerogels with a blocky shape. When attempting to obtain carbon aerogels in the form of spheres, fibers, or films, special techniques are required. In the first half of this review, we summarize previous reports on RF-based carbon aerogels in the form of spheres, hollow-fibers, and films, and in the latter half, we describe recent studies on organic and carbon aerogel films derived from polyimides.