Hydrothermal preparation of fluorinated graphene hydrogel for high-performance supercapacitors
Hydrothermal preparation of fluorinated graphene hydrogel for high-performance supercapacitors
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DOI：
10.1016/j.jpowsour.2016.02.057
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发表时间：
2016-04-30
影响因子：
9.2
通讯作者：
Feng, Wei
中科院分区：
文献类型：
--
作者：
An, Haoran;Li, Yu;Feng, Wei
采用一步水热法合成了氟化石墨烯水凝胶（FGH），并将其作为无粘结剂/添加剂的超级电容器电极材料。沿着氧化石墨烯（GO）的还原，氟原子通过取代过程与残留的酚、醚或羰基结合到石墨烯骨架中，随后形成不同的氟物种。氟含量和C-F键构型容易通过水热温度调节。X射线光电子能谱（XPS）和傅里叶变换红外光谱（FTIR）表明，所制备的FGH中主要存在半离子C-F键。FGH中的半离子C-F键有利于离子传输，提高电导率，并为法拉第反应提供活性位点。因此，FGH的电化学性能优于相同水热工艺制备的无氟石墨烯水凝胶。在水热温度为150 ℃时制备的FGH具有最高的比电容（227 F g（-1））和最好的倍率性能。相应的双极超级电容器在50 A g（-1）的电流密度下提供高达50.05 kW Kg（-1）的功率密度。这些结果表明，FGH是高功率超级电容器领域具有巨大潜力的理想电极材料。(C)© 2016 Elsevier B. V.版权所有。
Fluorinated graphene hydrogels (FGHs) are synthesized through a one-step hydrothermal process and applied as the binder/additive-free electrode materials for supercapacitors. Along with the reduction of graphene oxide (GO), fluorine atoms incorporate into the graphene framework through the substitution process with the residual phenol, ether or carbonyl groups, forming different fluorine species subsequently. The fluorine content and the C-F bond configuration are easily adjusted by the hydrothermal temperature. X-ray photo electron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectra indicate the mainly existent of semi-ionic C-F bonds in the prepared FGHs. The semi-ionic C-F bonds in FGHs facilitate the ion transport, enhance the electrical conductivity and provide active sites for the faradic reaction. Therefore, the electrochemical performances of FGHs are better than the fluorine-free graphene hydrogel prepared by the same hydrothermal process. FGH prepared at the hydrothermal temperature of 150 degrees C exhibit the highest specific capacitance (227 F g(-1)) and the best rate capability. The corresponding symmetric-supercapacitor delivers the power density as high as 50.05 kW Kg(-1) at the current density of 50 A g(-1). These results indicate the FGHs are the ideal electrode materials with the great potential in the field of high-power supercapacitors. (C) 2016 Elsevier B.V. All rights reserved.