檜から作ったナノポーラスカーボン : 細孔構造の制御と電気二重層キャパシタへの応用

Abstract

Nanoporous carbons were successfully prepared from cypress chips under a flow of super-heated steam. The cypress charcoals thus obtained were used as electrodes of electric double layer capacitor with 1 M H_2SO_4 electrolyte. Pore structure in cypress charcoals could be controlled by changing carbonization conditions (temperature of super-heated steam, supplying and transferring rates of chips). Under the condition with 15 kg/h supply of chips and 4.7 rpm rotation of transferring paddles, mesopore-rich charcoals with external surface area of about 500 m^2/g, which was comparable with microporous surface area, were obtained at 800～870℃ and micropore-rich charcoals with microporous surface area of about 900 m^2/g were obtained above 900℃. Electric double layer capacitor constructed from these cypress charcoals had relatively high capacitance, about 190 F/g with the current density of 50 mA/g and about 140 F/g with 1000 mA/g, which were comparable with the reference activated carbon. The performance rating defined by C_<1000>/C_<50> was in a range of 0.65～0.85, which was higher than the reference activated carbon.