Preparation of three dimensionally ordered macroporous carbon with mesoporous walls for electric double-layer capacitors

Abstract

Three dimensionally ordered macroporous (3DOM) carbons with mesoporous walls were prepared by a colloidal crystal templating method. A three dimensionally ordered composite consisting of monodisperse polystyrene (PS) latex (100-450 nm) and colloidal silica (5-50 nm) was prepared by an evaporation process of suspensions containing PS latex and colloidal silica in water. In the course of the heat treatment of this composite membrane at 573 K under an inert atmosphere, the PS was melted and penetrated into the spaces between the colloidal silica. The penetrated PS was carbonized during further heat treatment to provide a very thin carbon layer on the colloidal silica, and the macropore corresponding to the PS particle size was formed simultaneously. After this procedure, the 3DOM carbon with mesoporous walls was obtained by removing the silica particles. From the results of scanning electron microscope observations and nitrogen adsorption-desorption measurements, it was confirmed that the prepared carbon had a bimodal porous structure, and the sizes of macropores and mesopores of prepared carbon were in good agreement with the sizes of the PS and silica particles used as templates, respectively. The bimodal porous carbon, which had a specific surface area of 1500 m 2 g À1 and 5 nm mesopores, showed highest capacitance of 120 F g À1 in propylene carbonate solution containing 1 mol dm À3 (C 2 H 5 ) 4 NBF 4 . The mesopore size rather than macropore size gave significant effects on the rate capability of carbon electrode during charge and discharge. The bimodal porous carbon having 5 nm mesopores showed an excellent rate capability and its capacitance at a high current density of 4 A g À1 was 109 F g À1 .

Recent Advances in Continuum Modeling of Interfacial and Transport Phenomena in Electric Double Layer Capacitors

“…The dimensions of the simulated electrode structure were identical to those of the bimodal mesoporous carbon CP204-S15 electrodes synthesized. 166 Figure 6 shows the measured gravimetric capacitance C g (in F/g) of different bimodal carbon films 166 as a function of the specific surface area, ranging from 910 to 1030 m 2 /g, obtained using 1 M TEABF 4 in PC. Figure 6 also shows the numerically predicted gravimetric capacitance as a function of specific surface area.…”

“…The latter was varied by changing the macropore radius R 0 from 50 to 150 nm while other geometric parameters such as the carbon wall thickness and mesopore radius respectively remained 2 and 7 nm and identical to those of CP204-S15 mesoporous carbon. 166 The numerical results were obtained using either the solvated or the non-solvated effective ion diameters reported in the literature as a = 1.40 nm 159,160 or a = 0.68 nm, 158 respectively. It is evident that the predicted and experimentally measured gravimetric capacitances C g increased linearly with increasing specific surface area.…”

“…To avoid this simplification and faithfully simulate the porous electrode morphology, Wang 166 with (a) highly ordered macropores and (b) mesoporous walls separating the large pores. Figures 5c and 5d show schematics and dimensions of the mesoporous structure simulated.…”

Electrospun Metal Oxide/Carbon Nanofiber Composite Electrode for Supercapacitor Application

“…The interconnected mesopores sized 3-5 nm provide a good charge propagation and ability for high current loads. Moreover, high pore volumes with mesopores are beneficial for providing quick pathways for electrolyte transportation [66][67][68].…”

Double Layer Capacitance Properties of Monodisperse Carbon Particles with High Porosity Derived from Polyacrylonitrile Synthesized by Dispersion Polymerization

“…Porous carbon materials have been attracting wide attention for various applications such as adsorbents, 1 catalyst supports, 2 separation media, 3 electrodes for batteries 4 and capacitors, 5 hydrogen 6 and carbon dioxide 7 storing materials. During the past years, electric double layer capacitor (EDLC) is considered to be one of the most promising energy storage device owing to its long lifetime and high power density.…”