A highly flexible solid-state supercapacitor based on the carbon nanotube doped graphene oxide/polypyrrole composites with superior electrochemical performances

Flexible electrodes of ternary composites, in which highly conductive carbon nanotube films (CNFs) are coated with carbon nanotube-doped graphene oxide/polypyrrole (CNT-GO/PPy), have been fabricated via facile electrochemical synthesis. Long and short CNTs are separately doped into the composites (lCNT-GO/PPy and sCNT-GO/PPy) and their electrochemical performances are compared. Electrochemical measurements indicate that the doping of CNTs in the composites significantly improves the electrochemical behaviors of the GO/PPy electrodes. Notably, the lCNT-GO/PPy electrodes show superior electrochemical properties with respect to the sCNT-GO/PPy electrodes, which is related to the introduction of abundant CNTs in the former electrodes and their special microstructures. Two symmetric electrodes with the lCNT-GO/PPy composites coated on CNFs are assembled to fabricate a solid-state supercapacitor device, which features lightweight, ultrathinness, and high flexibility. The device achieves a high areal and volumetric specific capacitance of 70.0 mF cm(-2) at 10 mV s(-1) and 6.3 F cm(-3) at 0.043 A cm(-3), respectively. It also shows superior rate performance and cycle stability, with a capacitance retention rate of 87.7% for 10,000 cycles. The supercapacitor device fabricated is promising for the use in lightweight and flexible integrated electronics. (C) 2016 Elsevier B.V. All rights reserved.