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qun19870102

木虫 (小有名气)

[求助] 文献中的有个图实在看不懂,请大家帮忙解析一下,急!!!

(1)图中的横坐标是频率纵坐标是容量,这个图是怎么得到的或者是用什么测试方法得到的.
(2)图中红色和蓝色分别代表正极和负极,并且是在三电极体系中测得的。这里所说的正负极是指的组成的电容器的的正负极吗,如果是,这篇文章中的电容器是对称电容器,两个电极是基本相同的,为什么拿到三电极中测得的结果会差别那么大呢(如图中红色蓝色所示)?
(3)这是文章中对这幅图的解释。 Two and three-electrode cell were applied to deter-
mine total systemas well as electrodes of both polarity separately.Generally, for 1mHz frequency no significant improvement of capacitance (higher than 20%of initial value, i.e.without surfactant)was observed both for whole supercapacitors and for electrodes
considered separately. However, three-electrode cell investigation reveals interesting behavior of electrodes at higher frequencies.For positive electrode in 1mol L−1 H2SO4 enriched by 0.05mol L−1 anionic surfactant (sodium dodecyl sulphate solution) the capac-
itance reaches a peak of 450 F g−1 value at 1Hz frequency which is two times greater than for electrolyte without surfactant (see Fig. 5). Such discrepancy between capacitance behavior of single electrodes at the frequency range from 100mHz to 10Hz has been already observed especially for carbons rich in heteroatoms[22,23]. Themost convincing explanation for the observed anomaly is fact that among two capacitor electrodes one of them can pointout aggravated ability for good dynamic of charge propagation at higher frequencies. For this reason the second electrode supplies additional surplus capacitance to compensate this scarcity to equilibrate the total system. The question iswhy the negative electrode performs worse at higher frequencies, in other words, why the cations penetration into smaller pores is significantly aggravated.
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格格11

木虫 (小有名气)

【答案】应助回帖

qun19870102(金币+10): 很有帮助,谢谢呀 2011-10-24 14:57:03
有两种可能:一是直接用C= -1/(2*Pi*Z". 另一种(更可能)是计算了所谓的”real capacitance". 这是用C' = -Z“/(w|Z|^2).
4楼2011-10-24 11:18:44
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格格11

木虫 (小有名气)

【答案】应助回帖

上面的那个应该是半个括号。 但无法更改了。
5楼2011-10-24 11:21:33
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格格11

木虫 (小有名气)

严格地说Bode plot 只是有两张图组成, 一张是对数幅频特性,另一张是对数相频特性:参看http://hi.baidu.com/fwxh101/blog ... fecfa3a50f52f0.html
至于计算C 的方法资料很多,我先放两个:
J. Miller, R. Outlaw, B. Holloway, Science 2010, 329, 1637. (第一种)
P. Taberna, P. Simon, J. Fauvarque, J. Electrochem. Soc. 2003, 150, A292. (第二种)。这是几个法国人提出的(其中Simon 现在也是大牛)在欧洲用的很普遍。尤其是你贴的那篇文章是从波兰来的。 用后者的可能性更大一些。我们实验室也是常用这个的。
8楼2011-10-24 21:19:50
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格格11

木虫 (小有名气)

好吧,就先这两篇。
9楼2011-10-25 10:23:00
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