Kumar Amit, Kumar Nagesh, Sharma Yogesh, Leu Jihperng, Tseng Tseung Yuen
Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu, 300, Taiwan.
Institute of Electronics, National Chiao Tung University, Hsinchu, 300, Taiwan.
Nanoscale Res Lett. 2019 Aug 6;14(1):266. doi: 10.1186/s11671-019-3100-1.
Herein, we report a novel, simple, and cost-effective way to synthesize flexible and conductive rGO and rGO/MWCNT freestanding films. The effects of MWCNT addition on the electrochemical performance of rGO/MWCNT nanocomposite films are investigated in some strong base aqueous electrolytes, such as KOH, LiOH, and NaOH via three-electrode system. The supercapacitor behavior of the films is probed via cyclic voltammetry, galvanostatic charging-discharging, and electrochemical impedance spectroscopy. The structural and morphological studies of the films are performed by X-ray diffractometer, Raman spectrometer, surface area analyzer, thermogravimetric analysis, field emission scanning electron microscope and transmission electron microscope. The rGO/MWCNT film synthesized with 10 wt% MWCNTs (GP10C) exhibits high specific capacitance of 200 Fg, excellent cyclic stability with 92% retention after 15,000 long cycle test, small relaxation time constant (~ 194 ms), and high diffusion coefficient (7.8457 × 10 cm s) in 2 M KOH electrolyte. Furthermore, the symmetric supercapacitor coin cell with GP10C as both anode and cathode using 2 M KOH as electrolyte demonstrates high energy density of 29.4 Whkg and power density of 439 Wkg at current density 0.1 Ag and good cyclic stability with 85% retention of the initial capacitance at 0.3 Ag after 10,000 cycles. Such a high performance of the GP10C film in the supercapacitor can be ascribed to the large surface area and small hydration sphere radius and high ionic conductivity of K cations in KOH electrolyte.
在此，我们报告了一种新颖、简单且经济高效的方法来合成柔性导电的还原氧化石墨烯（rGO）和rGO/多壁碳纳米管（MWCNT）独立薄膜。通过三电极系统，研究了在一些强碱水溶液电解质（如KOH、LiOH和NaOH）中添加MWCNT对rGO/MWCNT纳米复合薄膜电化学性能的影响。通过循环伏安法、恒电流充放电和电化学阻抗谱来探究薄膜的超级电容器行为。利用X射线衍射仪、拉曼光谱仪、表面积分析仪、热重分析、场发射扫描电子显微镜和透射电子显微镜对薄膜进行结构和形态研究。含10 wt% MWCNT合成的rGO/MWCNT薄膜（GP10C）在2 M KOH电解质中表现出200 F/g的高比电容、在15000次长循环测试后具有92%的优异循环稳定性、小弛豫时间常数（~194 ms）和高扩散系数（7.8457×10 cm²/s）。此外，以GP10C作为阳极和阴极、使用2 M KOH作为电解质的对称超级电容器硬币电池在电流密度0.1 A/g时表现出29.4 Wh/kg的高能量密度和439 W/kg的功率密度，并且在10000次循环后于0.3 A/g时具有85%的初始电容保持率的良好循环稳定性。GP10C薄膜在超级电容器中的这种高性能可归因于KOH电解质中K⁺阳离子的大表面积、小水合球半径和高离子电导率。
