Carbon Nanotube-Bridged Graphene 3D Building Blocks for Ultrafast Compact Supercapacitors
Carbon Nanotube-Bridged Graphene 3D Building Blocks for Ultrafast Compact Supercapacitors
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DOI：
10.1021/nn507079x
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发表时间：
2015-02-01
期刊：
影响因子：
17.1
通讯作者：
Lee, Young Hee
中科院分区：
文献类型：
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作者：
Duy Tho Pham;Lee, Tae Hoon;Lee, Young Hee
在保持高功率密度的同时实现高电化学能量密度的主要障碍是能量与功率以及重量与体积密度之间的权衡。优化结构参数是绕过这些取舍的关键。本文报道了阳离子表面活性剂接枝的带正电的碳纳米管与带负电的氧化石墨烯之间的库仑相互作用，然后用氢氧化钾活化，合成了碳纳米管桥接的石墨烯3D构筑块。碳纳米管被插入到纳米多孔石墨烯层中，构建了柱撑3D结构，增加了可获得的表面积，并允许快速离子扩散。制得的石墨烯/碳纳米管薄膜具有良好的柔性，电导率为39400 S m(1)，合理的质量密度为1.06g cm(3)。用这些薄膜制备的超级电容器在离子液体电解液中表现出优异的电化学性能，根据总活性物质的厚度或质量，最大能量密度为117.2 WH L-1或110.6 WH kg(1)，最大功率密度为424kW L-1或400kW kg(1)。
The main obstacles to achieving high electrochemical energy density while retaining high power density are the trade-offs of energy versus power and gravimetric versus volumetric density. Optimizing structural parameters is the key to circumvent these trade-offs. We report here the synthesis of carbon nanotube (CNT)-bridged graphene 3D building blocks via the Coulombic interaction between positively charged CNTs grafted by cationic surfactants and negatively charged graphene oxide sheets, followed by KOH activation. The CNTs were intercalated into the nanoporous graphene layers to build pillared 3D structures, which enhance accessible surface area and allow fast ion diffusion. The resulting graphene/CNT films are free-standing and flexible with a high electrical conductivity of 39?400 S m(1) and a reasonable mass density of 1.06 g cm(3). The supercapacitors fabricated using these films exhibit an outstanding electrochemical performance in an ionic liquid electrolyte with a maximum energy density of 117.2 Wh L-1 or 110.6 Wh kg(1) at a maximum power density of 424 kW L-1 or 400 kW kg(1), which is based on thickness or mass of total active material.