Skrypnychuk Vasyl, Boulanger Nicolas, Nordenström Andreas, Talyzin Alexandr
Department of Physics, Umeå University, Umeå SE-901 87, Sweden.
J Phys Chem Lett. 2020 Apr 16;11(8):3032-3038. doi: 10.1021/acs.jpclett.0c00272. Epub 2020 Apr 3.
High-surface area activated graphene has a three-dimensional porous structure that makes it difficult to prepare dispersions. Here we report a general approach that allows the preparatioon of stable water-based dispersions/inks at concentrations of ≲20 mg/mL based on activated graphene using environmentally friendly formulations. Simple drying of the dispersion on the substrate allows the preparation of electrodes that maintain the high specific surface area of the precursor material (∼1700 m/g). The electrodes are flexible because of the structure that consists of micrometer-sized activated graphene grains interconnected by carbon nanotubes (CNTs). The electrodes prepared using activated graphene demonstrate performance superior to that of reduced graphene oxide in supercapacitors with KOH and TEA BF/acetonitrile electrolytes providing specific capacitance values of 180 and 137 F/g, respectively, at a specific current of 1 A/g. The high surface area of activated graphene in combination with the good conductivity of CNTs allows an energy density of 35.6 Wh/kg and a power density of 42.2 kW/kg to be achieved. The activated graphene dispersions were prepared in liter amounts and are compatible with most industrial deposition methods.
高比表面积的活性石墨烯具有三维多孔结构，这使得制备其分散体变得困难。在此，我们报道了一种通用方法，该方法基于活性石墨烯，使用环境友好型配方，能够在浓度≲20mg/mL的条件下制备稳定的水基分散体/油墨。将分散体简单干燥在基底上即可制备出电极，该电极能保持前驱体材料的高比表面积（约1700m²/g）。由于该结构由微米级的活性石墨烯颗粒通过碳纳米管（CNT）相互连接而成，所以电极具有柔韧性。使用活性石墨烯制备的电极在超级电容器中表现出优于还原氧化石墨烯的性能，在使用KOH和TEA BF₄/乙腈电解质时，在1A/g的特定电流下，比电容值分别为180和137F/g。活性石墨烯的高比表面积与碳纳米管的良好导电性相结合，可实现35.6Wh/kg的能量密度和42.2kW/kg的功率密度。活性石墨烯分散体的制备量可达升，并且与大多数工业沉积方法兼容。
