Department of Materials Science and Engineering and ‡Department of Mechanical Engineering, University of Maryland College Park , College Park, Maryland 20742, United States.
Nano Lett. 2016 Nov 9;16(11):7282-7289. doi: 10.1021/acs.nanolett.6b03888. Epub 2016 Oct 17.
Carbon nanomaterials exhibit outstanding electrical and mechanical properties, but these superior properties are often compromised as nanomaterials are assembled into bulk structures. This issue of scaling limits the use of carbon nanostructures and can be attributed to poor physical contacts between nanostructures. To address this challenge, we propose a novel technique to build a 3D interconnected carbon matrix by forming covalent bonds between carbon nanostructures. High temperature Joule heating was applied to bring the carbon nanofiber (CNF) film to temperatures greater than 2500 K at a heating rate of 200 K/min to fuse together adjacent carbon nanofibers with graphitic carbon bonds, forming a 3D continuous carbon network. The bulk electrical conductivity of the carbon matrix increased four orders of magnitude to 380 S/cm with a sheet resistance of 1.75 Ω/sq. The high temperature Joule heating not only enables fast graphitization of carbon materials at high temperature, but also provides a new strategy to build covalently bonded graphitic carbon networks from amorphous carbon source. Because of the high electrical conductivity, good mechanical structures, and anticorrosion properties, the 3D interconnected carbon membrane shows promising applications in energy storage and electrocatalysis fields.
碳纳米材料具有优异的电学和力学性能，但当它们被组装成块状结构时，这些优越的性能往往会受到影响。这种规模化的问题限制了碳纳米结构的应用，这可以归因于纳米结构之间较差的物理接触。为了解决这一挑战，我们提出了一种通过在碳纳米结构之间形成共价键来构建 3D 互连碳基质的新方法。高温焦耳加热以 200 K/min 的加热速率将碳纤维（CNF）薄膜加热到 2500 K 以上，使相邻的碳纤维与石墨碳键融合在一起，形成 3D 连续碳网络。碳基质的体电导率增加了四个数量级，达到 380 S/cm，面电阻为 1.75 Ω/sq。高温焦耳加热不仅使碳材料在高温下快速石墨化，而且为从非晶碳源构建共价键合的石墨碳网络提供了一种新策略。由于高导电性、良好的机械结构和耐腐蚀性，3D 互连碳膜在储能和电催化领域显示出有前途的应用。
