Three dimensional reduced graphene hydrogels with tunable pore sizes using thiourea dioxide for electrode materials in supercapacitors
Three dimensional reduced graphene hydrogels with tunable pore sizes using thiourea dioxide for electrode materials in supercapacitors
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DOI：
10.1016/j.electacta.2015.07.150
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发表时间：
2015-09
影响因子：
6.6
通讯作者：
Lingbao Xing;Jing-Li Zhang;Juan Zhang;Shu-Fen Hou;Jin Zhou;Weijiang Si;Hongyou Cui;Shuping Zhuo-Shuping-Zhu
中科院分区：
文献类型：
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作者：
Lingbao Xing;Jing-Li Zhang;Juan Zhang;Shu-Fen Hou;Jin Zhou;Weijiang Si;Hongyou Cui;Shuping Zhuo-Shuping-Zhu
在目前的工作中，我们展示了一种快速简便的方法，通过在氧化石墨烯（GO）和氨的水溶液中使用二氧化硫脲作为还原剂来制备三维（3D）还原石墨烯水凝胶（RGHs）。通过x射线粉末衍射、拉曼光谱和傅里叶变换红外光谱可以证实氧化石墨烯悬浮液向水凝胶的转变。通过氮气吸附实验、扫描电镜和x射线光电子能谱分析，证实了其孔隙度、结构和表面化学性质。添加不同量的二氧化硫脲后，得到的RGHs还原程度不同，比表面积和孔径分布可控，性能与超级电容器不同。在KOH电解液中，基于RGHs的超级电容器在0.1 a g−1时的比电容分别为258.6、167.3和198.3 F g−1。此外，该电容在重复充放电循环测试中也表现出良好的电化学稳定性和高度的可逆性。
In present work, we demonstrate a rapid and easy approach to fabricate three-dimensional (3D) reduced graphene hydrogels (RGHs) by using thiourea dioxide as reducing agents in an aqueous solution of graphene oxide (GO) with ammonia. The transformation of GO suspension to the hydrogels can be confirmed by X-ray powder diffraction, Raman spectroscopy, and Fourier transform infrared spectroscopy. The hierarchical porosity, structure and surface chemical properties can be demonstrated by N2sorption experiments, scanning electron microscopy and X-ray photoelectron spectroscopy. With adding different amounts of thiourea dioxide, the obtained RGHs behave different degree of reduction, controlled specific surface area and pore size distribution, and unlike performances in supercapacitors. Benefiting from well-defined and cross-linked 3D porous network architectures, the supercapacitors based on the RGHs in KOH electrolyte exhibited a high specific capacitance of 258.6, 167.3 and 198.3 F g−1at 0.1 A g−1for RGHs-1, RGHs-2 and RGHs-5, respectively. Furthermore, this capacitance also showed good electrochemical stability and a high degree of reversibility in the repetitive charge/discharge cycling test.