Nishihara Hirotomo, Itoi Hiroyuki, Kogure Taichi, Hou Peng-Xiang, Touhara Hidekazu, Okino Fujio, Kyotani Takashi
Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1, Katahira, Aoba-ku, Sendai, 980-8577, Japan.
Chemistry. 2009;15(21):5355-63. doi: 10.1002/chem.200802406.
An ordered microporous carbon, which was prepared with zeolite as a template, was used as a model material to understand the ion storage/transfer behavior in electrical double-layer capacitor (EDLC). Several types of such zeolite-templated carbons (ZTCs) with different structures (framework regularity, particle size and pore diameter) were prepared and their EDLC performances were evaluated in an organic electrolyte solution (1 M Et(4)NBF(4)/propylene carbonate). Moreover, a simple method to evaluate a degree of wettability of microporous carbon with propylene carbonate was developed. It was found that the capacitance was almost proportional to the surface area and this linearity was retained even for the carbons with very high surface areas (>2000 m(2) g(-1)). It has often been pointed out that thin pore walls limit capacitance and this usually gives rise to the deviation from linearity, but such a limitation was not observed in ZTCs, despite their very thin pore walls (a single graphene, ca. 0.34 nm). The present study clearly indicates that three-dimensionally connected and regularly arranged micropores were very effective at reducing ion-transfer resistance. Despite relatively small pore diameter ZTCs (ca. 1.2 nm), their power density remained almost unchanged even though the particle size was increased up to several microns. However, when the pore diameter became smaller than 1.2 nm, the power density was decreased due to the difficulty of smooth ion-transfer in such small micropores.
以沸石为模板制备的有序微孔碳被用作模型材料，以了解双电层电容器（EDLC）中的离子存储/转移行为。制备了几种具有不同结构（骨架规整度、粒径和孔径）的此类沸石模板碳（ZTC），并在有机电解质溶液（1 M四乙基氯化铵四氟硼酸盐/碳酸丙烯酯）中评估了它们的EDLC性能。此外，还开发了一种简单的方法来评估微孔碳与碳酸丙烯酯的润湿性。结果发现，电容几乎与表面积成正比，即使对于表面积非常高（>2000 m² g⁻¹）的碳，这种线性关系也得以保持。人们经常指出，薄的孔壁会限制电容，这通常会导致偏离线性关系，但在ZTC中并未观察到这种限制，尽管它们的孔壁非常薄（单层石墨烯，约0.34 nm）。本研究清楚地表明，三维连通且规则排列的微孔在降低离子转移电阻方面非常有效。尽管ZTC的孔径相对较小（约1.2 nm），但即使粒径增加到几微米，它们的功率密度几乎保持不变。然而，当孔径小于1.2 nm时，由于在如此小的微孔中离子难以顺利转移，功率密度会降低。
