IBS Center for Integrated Nanostructure Physics, Institute for Basic Science, Sungkyunkwan University , Suwon 440-746, Republic of Korea.
ACS Nano. 2015 Feb 24;9(2):2018-27. doi: 10.1021/nn507079x. Epub 2015 Feb 5.
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.
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、重量与体积密度之间的权衡。优化结构参数是克服这些权衡的关键。我们在此报告了通过正电荷 CNT 与负电荷氧化石墨烯片之间的库仑相互作用合成碳纳米管（CNT）桥接的石墨烯 3D 构建块，然后进行 KOH 活化。CNT 被插入到纳米多孔石墨烯层中以构建支柱 3D 结构，从而增加可及表面积并允许快速离子扩散。得到的石墨烯/CNT 薄膜是独立的和灵活的，具有 39400 S m(-1) 的高电导率和 1.06 g cm(-3) 的合理质量密度。使用这些薄膜制造的超级电容器在离子液体电解质中表现出出色的电化学性能，在最大功率密度为 424 kW L(-1) 或 400 kW kg(-1) 时，最大能量密度为 117.2 Wh L(-1) 或 110.6 Wh kg(-1)，这是基于总活性材料的厚度或质量。
