Isolating the effect of pore size distribution on electrochemical double-layer capacitance using activated fluid coke
Isolating the effect of pore size distribution on electrochemical double-layer capacitance using activated fluid coke
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DOI：
10.1016/j.jpowsour.2015.09.030
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发表时间：
2015-12
影响因子：
9.2
通讯作者：
J. E. Zuliani;S. Tong;D. Kirk;C. Jia
中科院分区：
文献类型：
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作者：
J. E. Zuliani;S. Tong;D. Kirk;C. Jia
电化学双层电容器（EDLC）利用高比表面积（SSA）材料的电容性双电层中的物理离子吸附来存储电能。以前的工作表明，当孔径小于1 nm时，SSA归一化电容增加。然而，仍然存在关于电荷存储机制的不确定性，因为没有在所有微孔材料中观察到增强的SSA归一化电容。在以前的研究中，电极材料的总比表面积和化学组成没有被控制。目前的工作是第一次报道的研究，系统地比较了由相同原料制备的活性炭的性能，具有相似的化学组成和比表面积，但不同的孔径分布。制备具有类似SSA但不同孔径的样品并不简单，因为增加孔径导致SSA降低。这项研究观察到，微孔活性炭具有更高的SSA归一化电容，14.1 μF cm−2，而中孔材料为12.4 μF cm−2。然而，这种增强的SSA归一化电容仅在阈值工作电压以上观察到。因此，可以得出结论，需要最小的施加电压来诱导这些亚纳米微孔中的离子吸附，这增加了电容。
Electrochemical double-layer capacitors (EDLCs) use physical ion adsorption in the capacitive electrical double layer of high specific surface area (SSA) materials to store electrical energy. Previous work shows that the SSA-normalized capacitance increases when pore diameters are less than 1 nm. However, there still remains uncertainty about the charge storage mechanism since the enhanced SSA-normalized capacitance is not observed in all microporous materials. In previous studies, the total specific surface area and the chemical composition of the electrode materials were not controlled. The current work is the first reported study that systematically compares the performance of activated carbon prepared from the same raw material, with similar chemical composition and specific surface area, but different pore size distributions. Preparing samples with similar SSAs, but different pores sizes is not straightforward since increasing pore diameters results in decreasing the SSA. This study observes that the microporous activated carbon has a higher SSA-normalized capacitance, 14.1 μF cm−2, compared to the mesoporous material, 12.4 μF cm−2. However, this enhanced SSA-normalized capacitance is only observed above a threshold operating voltage. Therefore, it can be concluded that a minimum applied voltage is required to induce ion adsorption in these sub-nanometer micropores, which increases the capacitance.