Abstract:

A one-step electrochemical exfoliation method was appliled to electrolyze a graphite rod in the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF₄]), and the exfoliation product was thermal-treated to obtain graphene/ionic liquid composite (GNs/[Bmim][BF₄]). Then, the composite was characterized by methods of infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray powder diffraction (XRD), and Raman spectroscopy. The plenty porous structure which can facilitates the retention of the electrode structure and the transfer of charge during charge and discharge was found in the composite of GNs/[Bmim][BF₄]. When the composite was used in supercapacitor electrode, the performence was found to be superior to graphite. At 0.2 A/g current density, the specific capacitance can reach 221.32 F/g, and when the power density was 456.32 W/kg, the energy density was up to 83.51 (W·h)/kg.

Key words: ionic liquid, electrochemistry, electrolysis, composite, specific capacitance, energy density

摘要：

应用一步电化学剥离法，在离子液体1-丁基-3-甲基咪唑四氟硼酸盐([Bmim][BF₄])电解液中电解石墨棒，产物进行热处理，制得石墨烯/离子液体复合物(GNs/[Bmim][BF₄])。对此复合物进行了红外光谱(FT-IR)、扫描电镜(SEM)、X射线粉末衍射(XRD)、拉曼光谱(Raman)等表征，发现GNs/[Bmim][BF₄]复合物具有良好的孔隙结构，在充放电过程中有利于电极结构的保持和电荷的转移。将其应用到超级电容器中，发现其性能较石墨要更加优异，在0.2 A/g电流密度下，比电容可达到221.32 F/g，在功率密度为456.32 W/kg下，能量密度可达83.51 (W·h)/kg。

关键词: 离子液体, 电化学, 电解, 复合物, 比电容, 能量密度