Preparation and Characterization of Carbon Nanotubes-Based Composite Electrodes for Electric Double Layer Capacitors

Abstract

E-mail: sjpark@inha.ac.krReceived November 26, 2011, Accepted February 3, 2012In this work, we prepared activated multi-walled carbon nanotubes/polyacrylonitrile (A-MWCNTs/C)composites by film casting and activation method. Electrochemical properties of the composites wereinvestigated in terms of serving as MWCNTs-based electrode materials for electric double layer capacitors(EDLCs). As a result, the A-MWCNTs/C composites had much higher BET specific surface area, and porevolume, and lower volume ratio of micropores than those of pristine MWCNTs/PAN ones. Furthermore, somefunctional groups were added on the surface of the A-MWCNTs/C composites. The specific capacitance of theA-MWCNTs/C composites was more than 4.5 times that of the pristine ones at 0.1 V discharging voltageowing to the changes of the structure and surface characteristics of the MWCNTs by activation process.Key Words : Multi-walled carbon nanotubes, Polyacrylonitrile, Composites, Activation, ElectrochemicalpropertiesIntroductionIn recent years, electrochemical capacitors have beenstudied in terms of their practical application as high powerdevices, since they have higher power density than batteriesand higher energy density than ordinary capacitors, as wellas a long cycle life. Electrochemical capacitors can bedivided into two types according to the energy storage mech-anism: electrochemical double-layer capacitors (EDLCs)and redox supercapacitors. EDLCs are being considered fora variety of applications such as the capacitive deionizationof water and as pulse power sources for cellular devices.