以还原氧化石墨烯网络/金线构建高性能柔性线型电化学电容器

High-performance flexible wire-shaped electrochemical capacitors based on gold wire@reduced graphene oxide

  • 摘要: 将金丝插入盛有氧化石墨烯和抗坏血酸混合物的毛细管中,密封条件下于30℃反应48小时制得具有三维网络结构的还原氧化石墨烯/金线(rGON/WAu)柔性复合纤维。通过扫描电子显微镜观测,发现rGON/WAu复合纤维由三维网络结构的还原氧化石墨烯包裹在金丝周围形成。用电化学测试方法详细研究了rGON/WAu复合纤维的电容性能,结果表明:当扫描速度为1 mV s-1时,纤维的长度和质量比电容分别可达5.47 mF cm-1和176.7 F g-1。以磷酸/聚乙烯醇为凝胶电解质,rGON/WAu为电极组装的对称全固态柔性电化学电容器的长度、面积和体积比电容分别可达到2.06 mF cm-1、6.87 mF cm-2和411.9 mF cm-3,其功率密度为0.017 mW cm-2时,能量密度可达9.48×10-4 mWh cm-2。此外,以rGON/WAu为电极的柔性超级电容器还具有很好的稳定性和柔性,三个柔性电容器串联充电后可以点亮电压阈值为2.5 V的发光二极管。

     

    Abstract: Flexible gold@reduced graphene oxide sheathed wires (WAu@rGO) were prepared by soaking a gold wire (100 μm in diameter) in the center of glass capillaries with inner diameters of 1.0, 1.3 and 1.8 mm in a suspension of graphene oxide (GO) in a L-ascorbic acid aqueous solution at 30℃ for 48 h. The WAu@rGO wires were obtained after removal of the capillaries, and their microstructures were characterized by SEM and their electrochemical properties as flexible electrodes in electrochemical capacitors were investigated by electrochemical tests. Results show that the specific capacitance of the WAu@rGO wire with the smallest diameter is 5.47 mF cm-1 or 176.7 F g-1 at a scan rate of 1 mV s-1. A symmetric all-solid-state flexible electrochemical capacitor based on the two smallest wires and a polyvinyl alcohol/H3PO4 gel electrolyte shows a maximum capacitance of 2.06 mF cm-1, or 6.87 mF cm-2 or 411.9 mF cm-3. The solid-state capacitor has energy and power densities of 9.48×10-4 mWh cm-2 and 0.017 mW cm-2, respectively, based on the whole device. Three devices connected in series can light a light-emitting diode with a threshold voltage of 2.5 V. Moreover, the device also shows a long cyclic stability and a good bending ability.

     

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