Oxygen functional groups and electrochemical capacitive behavior of incompletely reduced graphene oxides as a thin-film electrode of supercapacitor
Oxygen functional groups and electrochemical capacitive behavior of incompletely reduced graphene oxides as a thin-film electrode of supercapacitor
复制标题
DOI：
10.1016/j.electacta.2013.11.040
复制
发表时间：
2014-01-10
影响因子：
6.6
通讯作者：
Park, Seung Bin
中科院分区：
文献类型：
--
作者：
Oh, Young Joon;Yoo, Jung Joon;Park, Seung Bin
研究了不完全还原氧化石墨烯中羧基、苯酚、羰基和醌等含氧官能团对电化学电容行为的影响。为了制备RGO薄膜电极，应用通过（i）滴加和蒸发氧化石墨烯（GO）溶液、（ii）照射脉冲光和（iii）在类似于360 ℃的200 ℃下热处理的简单制造工艺。值得注意的是，脉冲光照射可以有效地防止热还原过程中沉积的GO薄膜的变形。从XRD分析，层间距离的RxD逐渐减少，从0.379到0.354 nm。随着热还原温度从200 ℃升高到360 ℃，XPS O Is谱分析表明，R10的羧基和苯酚原子百分比分别保持在5.40 +/- 0.36和4.77 +/-0.41at%。同时，随着热还原温度的变化，RGO中的羰基和醌的含量分别从3.10at%逐渐下降到1.81at%和从1.32at%逐渐下降到0.65at%。对于所有RGO薄膜电极，在6 M KOH中的CV测量的比电容维持为约1.5V。在5 mV s（-1）扫描时，220 F g（-1）。然而，在1 M H2SO 4中，比电容从171逐渐降低到136 F g（-1）。在6 M KOH、1 M H2SO 4和0.5M Na 2SO 4中进行100，000次循环后，RGO（200 ℃）电极显示出约100，000次循环。分别为初始电容的92%、54%和104%。在循环测试后，参与赝电容法拉第反应的氧官能团的原子百分比降低。特别是在1 M H_2SO_4中，醌基减少到约1.5。48%的初始原子百分比，这似乎是电容急剧下降的主要原因。在6 M KOH中，羧基或酚基的每单位原子百分比的比赝电容为12.59 F g（-1）at%（-1）。对于1 M H2SO 4中的羰基，其值略微偏离，为13.55 F g（-1）at%（-1）。对于1 M H2SO 4中的醌基团，其为27.09 F（C）2013 Jong-Huy Kim。由爱思唯尔有限公司出版。保留所有权利。
For incompletely reduced graphene oxides (RGOs), an effect of oxygen functional groups such as carboxyl, phenol, carbonyl, and quinone on electrochemical capacitive behavior was studied. To prepare RGO thin-film electrodes, a simple fabrication process by (i) dropping and evaporating the graphene oxide (GO) solution, (ii) irradiating pulsed light, and (iii) heat-treating at 200 similar to 360 degrees C was applied. It was notable that the pulsed light irradiation was effective to prevent the disfiguring of deposited GO thinfilm during the thermal reduction. From XRD analyses, interlayer distances of the RGOs were gradually decreased from 0.379 to 0.354 nm. As increasing the thermal reduction temperature from 200 to 360 degrees C, XPS O Is spectra analyses showed that the atomic percentages of carboxyl and phenol of the RGOs were sustained as 5.40 +/- 0.36 and 4.77 +/- 0.41 at% respectively. Meanwhile, those of carbonyl and quinone of the RGOs were gradually declined from 3.10 to 1.81 and from 1.32 to 0.65 at% with different thermal reduction temperature respectively. For all RGO thin-film electrodes, the specific capacitance from the CV measurement in 6 M KOH was sustained as ca. 220 F g(-1) at the scan of 5 mV s(-1). However, in 1 M H2SO4, the specific capacitance was gradually decreased from 171 to 136 F g(-1). After 100,000 cycles in 6M KOH, 1 M H2SO4, and 0.5 M Na2SO4, the RGO (200 degrees C) electrodes showed ca. 92, 54, and 104% of the initial capacitances respectively. The atomic percentages of the oxygen functional groups involved in the pseudocapacitive Faradaic reaction were decreased after the cycle test. Especially in 1 M H2SO4, quinone group was decreased to ca. 48% of initial atomic percentage, which seems to be a main reason for the drastic reduction of capacitance. The specific pseudocapacitance per unit atomic percentage for either carboxyl or phenol group in 6 M KOH was obtained as 12.59 F g(-1) at%(-1). For carbonyl group in 1 M H2SO4, it was a slightly deviated value as 13.55 F g(-1) at%(-1). For quinone group in 1 M H2SO4, it was 27.09 F (C) 2013 Jong-Huy Kim. Published by Elsevier Ltd. All rights reserved.