Macro/meso/microporous carbon monoliths doped with sulfur have been prepared from sulfonated poly(divinylbenzene) networks followed by the activation with CO 2 resulted in the activated carbon monoliths with high surface area of 2400 m 2 g 1 . The monolithic electrode of the activated carbon shows remarkably high specific capacitance (175 F g 1 at 5 mV s 1 and 206 F g 1 at 0.5 A g 1 ).Increasing demands for the electrochemical devices, such as batteries, 1 fuel cells, 2 and electric double-layer 5 capacitors (EDLCs), 3-6 has triggered the development of porous carbon materials. The physical properties of carbon materials, including surface area, pore volume and pore size, must be controlled to be suitable for each application, because they are closely related to the electrochemical performance. A practical polarized electrode material for EDLCs is activated carbon with a high specific surface area 7-9 because EDLCs are based on electrostatic interactions, i.e. the electric charge is accumulated on an electric double-layer of the polarized electrode, and the electrodes with 10 the higher specific surface area can store higher energy. However, the conventional electrodes consisting of microporous carbon particles or powders are not effective enough because the narrow and disordered pores inbetween particles or powders are not suitable for the effective transport of ions to the micropore surfaces. In other words, a certain portion of micropores are inaccessible for ions and remain unused. For the better capacitive characteristics, therefore, it is indispensable for porous carbons to have the well-defined larger pores (mesopores and 15 macropores) in addition to the micropores. The mesopores and macropores facilitate the diffusion of the electrolyte ions in the materials while the micropores can provide abundant adsorbing sites for ions. 7,10,11 Thus, great efforts are focused on the preparation of macro/microporous, meso/microporous, and macro/meso/microporous hierarchically porous carbons for EDLCs. [12][13][14][15][16][17][18][19][20][21] Monolithic porous carbons are more advantageous for EDLCs rather than the traditional composite pellet electrodes, since the pellet electrodes are fabricated using a mixture of activated carbon 20 powders and binders, such as polytetrafluoroethylene (PTFE), which lower the electric conductivity, and the electrodes are possibly broken into fragments during the charge-discharge cycles. In addition, there is a possibility

An all-solid-state electric double-layer capacitor was fabricated with an inorganic-organic hybrid membrane from 3-glycidoxypropyltrimethoxysilane, tetraethoxysilane, and orthophosphoric acid as an electrolyte, and activated carbon fiber cloth as polarized electrodes. The electrochemical properties of the capacitor were studied in a temperature range from room temperature to 100°C. The specific capacitance of the capacitor was 41 F/g at 100°C with 12% relative humidity, and the capacitor showed good cycle performance.Electric double-layer capacitors ͑EDLCs͒ have recently attracted attention because of their practical applications as energy storage devices for memory backups, electric vehicles, and other devices. [1][2][3][4][5][6][7][8][9][10][11] Typical EDLCs are composed of two polarized electrodes and a liquid electrolyte. 1-3 The use of a liquid electrolyte causes some disadvantages such as electrolyte leakage, solvent corrosion, packing difficulty, and less compactness. To overcome these disadvantages, replacing a liquid electrolyte with a solid or gel electrolyte is proposed. In addition, the operation at high temperatures is required. However, the EDLCs using a liquid electrolyte are unable to operate at high temperatures because of volatilization of the solvent. By using a solid or gel electrolyte, the operation at high temperatures would be possible. Thus, all-solid-state capacitors have been strongly desired in recent years. All-solid-state capacitors were investigated during the past decades. 4-11 For example, Staiti et al. fabricated an all-solid-state EDLC using Nafion as a solid electrolyte. 4,5 The characteristics of the capacitor were studied in a voltage window of 0-1 V. The cyclic voltammograms were almost rectangular, and the charge-discharge curves were linear, suggesting the ideal capacitive behavior. A gel electrolyte impregnated with an aqueous or organic electrolyte solution in an organic polymer matrix was also used. 6-11 By swelling with an aqueous solution, the gel electrolyte showed high conductivity, leading to high specific capacity. [6][7][8][9] In either case, the all-solid-state capacitors were not operated at high temperature because the organic polymers generally show low thermal stability and the electrolyte solutions evaporate at high temperatures. However, inorganic materials generally have thermal stability.We have fabricated all-solid-state EDLCs using acid-doped inorganic silica gels as an electrolyte and activated carbon powders hybridized with the gels as polarized electrodes, and the capacitance of these all-solid-state capacitors was comparable to that of the capacitors with liquid electrolytes. 12-14 However, these gels were obtained as powders and have poor shaping ability. The use of organic polymer components should contribute to changing these gel powders to flexible membranes. We have reported that proton conductive inorganic-organic hybrid membranes from 3-glycidoxypropyltrimethoxysilane ͑GPTMS͒, tetraethoxysilane ͑TEOS͒, and phosphoric acid were flexible and s...

Macro/meso/microporous carbon monoliths doped with sulfur have been prepared from sulfonated polydivinylbenzene networks followed by the activation with CO 2 resulted in the activated carbon monoliths with high surface area of 2400 m 2 g −1 . The monolithic electrode of the activated carbon shows remarkably high specific capacitance (175 F g −1 at 5 mV s −1 and 206 F g −1 at 0.5 A g −1 ). INTRODUCTIONIncreasing demands for the electrochemical devices, such as batteries [1], fuel cells [2], and electric double-layer capacitors (EDLCs) [3,4], has triggered the development of porous carbon materials. The physical properties of carbon materials, including surface area, pore volume and pore size, must be controlled to be suitable for each application, because they are closely related to the electrochemical performance. A practical polarized electrode material for EDLCs is activated carbon with a high specific surface area [5,6] because EDLCs are based on electrostatic interactions, i.e., the electric charge is accumulated on an electric double-layer of the polarizable electrode, and the electrodes with the higher specific surface area can store more energy. However, the conventional electrodes consisting of microporous carbon particles or powders are not effective enough because the narrow and disordered pores in-between particles or powders are not suitable for the effective transport of ions to the micropore surfaces. In other words, a certain portion of micropores are inaccessible for ions and remain unused. For the better capacitive characteristics, therefore, it is indispensable for porous carbons to have the well-defined larger pores (mesopores and macropores) in addition to the micropores. The mesopores and macropores facilitate the diffusion of the electrolyte ions in the materials while the micropores can provide abundant adsorbing sites for ions [5,7,8]. Thus, great efforts are focused on the preparation of macro/microporous, meso/microporous, and macro/meso/microporous hierarchically porous carbons for EDLCs [9][10][11][12][13][14]. Monolithic porous carbons are more advantageous for EDLCs rather than the traditional composite pellet electrodes, because the pellet electrodes are fabricated using a mixture of activated carbon powders and binders, such as polytetrafluoroethylene (PTFE), which lower the electric conductivity, and the electrodes are possibly broken into fragments during the charge-discharge cycles. In addition, there is a possibility that binders unfavorably fill the pores of the activated carbons. Meanwhile, monolithic carbons with continuous skeletons can reduce the internal resistance of the electrode because no binders are needed and all of the pores should remain open and accessible. Hence, the porous carbon monoliths with high surface area are expected to possess the large capacity and show good cycle characteristics. However, there have been very