Nowadays flexible solid-state supercapacitors (FSCs) have received more and more attention than conventional capacitors due to the good operability and flexible fabrication process as well as high specific/volumetric energy density. In general,carbon based materials including amorphous carbon,carbon nanotube,grapheme,etc. can be used to fabricate electrolytic double-layer capacitance(EDLC)-type FSCs due to its extraordinary cyclic stability at high current density. Aligned carbon nanotube(ACNT)arrays are one of the ideal electrode candidates for energy storage due to their good capacity,highly efficient charge transfer rate,excellent rate performance and long cycle life compared with those of other carbon-based materials carbon nanotubes. However,the low density and the weak interaction between the carbon tubes cause the CNT arrays to tend to easily collapse during processing and transferring. Thus pure carbon nanotube arrays are unable to be directly used to assemble flexible electronic devices. In this paper, we use ethyl alcohol to shrink the CNT array to increase the density and mechanical strength. At the same time we embed the conductive polyvingle alcohol (PVA) gel into the carbon nanotube array to fabricate a flexible solid supercapacitor. Hydrogel-based solid electrolytes have been long considered to be used to prepare FSCs, because this method possesses obvious advantages including low cost,good environmental compatibility and simple manufacturing process. The ACNT/PVA complex can maintain good mechanical stability and flexibility during its folding and bending,and can also keep the high orientation of carbon nanotubes. The maximum capacitance of the hybrid flexible device can reach 458 mF·cm?3at a current density of 10 mA·cm?3, which is much higher than the capacitance reported in the literature. After 5000 charging-discharging cycles,a capacity still keeps nearly 100%. The maximum energy density of CNTs/gel composite device can reach 0.04 mW·h·cm?3with an average power density of 3.7 mW·cm?3. The capacitance can be further increased to 618 mF·cm?3by a simple in-situ electrochemical oxidation treatment. The energy density can be further increased to 0.07 mW·h·cm?3by the electro-oxidation treatment. The electrochemical performance of the device is far superior to that of EDLC-typed FSC reported in the literature. Additionally the equivalent series resistance (RESR) of the devices decreases from 120 ? to 30 ? and also the charge transfer resistance declines from 90 ? to 10 ?. This is mainly due to the effect of pseudo capacitance and electro-wetting effect caused by electro-oxidation. This easy-to-assemble hybrid devices thus potentially pave the way for manufacturing wearable devices and implantable medical devices.%柔性超级电容器因其加工方式灵活,具有高的能量密度和可剪裁可弯曲的特性,近年来受到广泛的关注.碳纳米管阵列凭借其自身良好的电化学性能、高效的电荷转移率和良好的循环寿命被视为理想的能量储存材料.然而原始碳纳米管阵列密度较小,且因管间较弱的相互作用力使得其在加工和转移过程中容易倒塌散落,从而限制了碳纳米管阵列直接用于组装柔性电子器件.本文应用无水乙醇对阵列进行收缩处理,在保持阵列高度取向优势的前提下大大增加了阵列的密度和机械强度,同时使用生物相容性好的聚乙烯醇(PVA)导电凝胶包埋碳纳米管阵列来制备柔性固态超级电容器件.PVA包埋的阵列复合体在折叠、弯曲过程中既能保持良好的机械稳定性和柔性,又能保持碳纳米管的高度取向性.使用原位电氧化对碳纳米管阵列外壁进行简单的电化学修饰,可以进一步提高该复合器件的性能.该方法为未来研发可穿戴电子器件以及可植入医学器件提供了新思路.
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