All-solid-state flexible supercapacitors based on papers coated with carbon nanotubes and ionic-liquid-based gel electrolytes

• Published in: Nanotechnology 2012-02, Vol.23 (6), p.065401-1-6
• Main Authors: Kang, Yu Jin, Chung, Haegeun, Han, Chi-Hwan, Kim, Woong
• Format: Article
• Language: English
• Subjects: Capacitors; Carbon nanotubes; Electrodes; Electrolytes; Nanostructure; Offices; Supercapacitors
• ISSN: 0957-4484; 1361-6528
• DOI: 10.1088/0957-4484/23/6/065401

All-solid-state flexible supercapacitors were fabricated using carbon nanotubes (CNTs), regular office papers, and ionic-liquid-based gel electrolytes. Flexible electrodes were made by coating CNTs on office papers by a drop-dry method. The gel electrolyte was prepared by mixing fumed silica nanopowders with ionic liquid, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][NTf2]). This supercapacitor showed high power and energy performance as a solid-state flexible supercapacitor. The specific capacitance of the CNT electrodes was 135 F g−1 at a current density of 2 A g−1, when considering the mass of active materials only. The maximum power and energy density of the supercapacitors were 164 kW kg−1 and 41 Wh kg−1, respectively. Interestingly, the solid-state supercapacitor with the gel electrolyte showed comparable performance to the supercapacitors with ionic-liquid electrolyte. Moreover, the supercapacitor showed excellent stability and flexibility. The CNT/paper- and gel-based supercapacitors may hold great potential for low-cost and high-performance flexible energy storage applications.