Investigation of the Ion Storage/Transfer Behavior in an Electrical Double-Layer Capacitor by Using Ordered Microporous Carbons as Model Materials
Investigation of the Ion Storage/Transfer Behavior in an Electrical Double-Layer Capacitor by Using Ordered Microporous Carbons as Model Materials
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DOI：
10.1002/chem.200802406
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发表时间：
2009-01-01
影响因子：
4.3
通讯作者：
Kyotani, Takashi
中科院分区：
文献类型：
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作者：
Nishihara, Hirotomo;Itoi, Hiroyuki;Kyotani, Takashi
以沸石分子筛为模板制备了有序微孔炭材料，并以此为模型材料研究了双电层电容器（EDLC）中的离子存储/传输行为。制备了几种具有不同结构（骨架规则性、粒径和孔径）的沸石模板碳（ZTC），并在所有有机电解质溶液（1 M Et_4NBF_4/碳酸丙烯酯）中评价了它们的EDLC性能。此外，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程度。发现电容几乎与表面积成正比，并且即使对于具有非常高表面积（>2000 m2 g（-1））的碳也保持这种线性。经常指出，薄的孔壁限制电容，并且这通常引起与线性的偏差，但是在ZTC中没有观察到这种限制，尽管它们的孔壁非常薄（单个石墨烯，约100 μ m）。0.34 nm）。本研究清楚地表明，三维连接和规则排列的微孔是非常有效的，在降低离子传递阻力。尽管相对较小的孔径ZTC（约。1.2 nm）时，它们的功率密度几乎保持不变，即使颗粒尺寸增加到几微米。然而，当孔径变得小于1.2 μ m时，由于难以在这样小的微孔中顺利地离子转移，功率密度降低。
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 ail organic electrolyte solution (1 M Et4NBF4/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 rim, the power density was decreased due to the difficulty of smooth ion-transfer in such small micropores.