High-performance supercapacitors based on vertically aligned carbon nanotubes and nonaqueous electrolytes

Abstract

We demonstrate the high performance of supercapacitors fabricated with vertically aligned carbon nanotubes and nonaqueous electrolytes such as ionic liquids and conventional organic electrolytes. Specific capacitance, maximum power and energy density of the supercapacitor measured in ionic liquid were ~75 F g(-1), ~987 kW kg(-1) and ~27 W h kg(-1), respectively. The high power performance was consistently indicated by a fast relaxation time constant of 0.2 s. In addition, electrochemical oxidation of the carbon nanotubes improved the specific capacitance (~158 F g(-1)) and energy density (~53 W h kg(-1)). Both high power and energy density could be attributed to the fast ion transport realized by the alignment of carbon nanotubes and the wide operational voltage defined by the ionic liquid. The demonstrated carbon-nanotube- and nonaqueous-electrolyte-based supercapacitors show great potential for the development of high-performance energy storage devices.

Review of Electrochemical Capacitors Based on Carbon Nanotubes and Graphene

“…The combination of high surface area and super-aligned structure enabled a high specific capacitance of 160 F/g in organic electrolyte. Kim et al [71] tested ultracapacitors made of aligned CNT in ionic liquids electrolyte and nonaqueous organic electrolyte. The specific capacitance of ultracapacitor in ionic liquid was 160 F/g and the specific power reached very high value of 990 KW/kg because of the fast ion transport of the super-aligned CNT.…”

Defect Engineered 2D Materials for Energy Applications

“…This gap between capacitors and battery performance has been a major roadblock in electrochemical energy storage. Electrochemical double-layer capacitors (EDLCs) or supercapacitors have been proposed to bridge the gap between these disparate devices by incorporating elements of both technologies [12,[28][29][30][31][32][33]. The charge is stored in the electric double layer, which forms at the electrode/electrolyte interfaces and leads to a double-layer capacitance (C dl ).…”

From Nanotechnology to Nanoengineering

“…In addition, their wide range of power capability makes it possible to hybridize them with other energy-storage devices, such as batteries and fuel cells. The performance of supercapacitors have been further improved by using nanostructures (Frackowiak et al 2006;Cheng et al 2011;Kong et al 2013;Hahm et al 2012;Kim et al 2012). It is worth mentioning here that carbon nanostructures compared to the other types of nanostructures have been preferred to be used in the electrode materials.…”