Printable and disposable supercapacitor from nanocellulose and carbon nanotubes

Supercapacitors are promising energy storage devices providing capacitance much higher than conventional capacitors and higher power density and longer cycle life than Li-batteries. We report printable and disposable supercapacitors fabricated from solution-processed carbon nanotube (CNT) composite material as active electrodes and nanocellulose (NC) as a separator. Use of a highly porous and electrically conducting CNT film as electrode materials eliminates the need of current collector. NC is a robust separator material used instead of conventional polymer separator films. Supercapacitor characterization was done with a galvanostatic discharge method according to an industrial standard. The capacitance of 1.8 cm2 devices was 14.9-16.5 mF (7.4-9.1 mF/cm2 or 2.4-2.9 F/g) and equivalent series resistance (ESR) 74-155 Ω. This type of low-cost energy storage devices fabricated from safe and environmentally friendly materials have obvious applications in autonomous intelligence and disposable low-end products.