Electrochemical properties enhancement of flexible textile based supercapacitor

Abstract

Recently developed textile and paper based supercapacitors are well-suited for wearable energy storage devices due to their mechanical flexibility and stretchability. In order to apply widely applications, wearable energy storage systems need to improve high energy density and power density. In this study, we fabricated the high energy and power density supercapacitor by using conductive polymer polypyrrole thin film and Ag nanowire network depositied on the MnO2 and CNT coated textile electrode. In addition, the effects of mechanical straining on carbon nanotube coated textiles are studied, and we demonstrate the pre-straining of the textile can result in an enhanced specific capacitance as well as power and energy densities. Two different carbon nanotube textiles based on polyester and cotton with different mechanical behaviors were examined, where the polyester textile showed an increase in specific capacitance from 53.6Fg-1 to 85.7Fg-1 after the textile was pre-strained to 30% permanent elongation prior to electrochemical testing, constituting a 37% enhancement. Similarly, the cotton textile showed an enhancement in specific capacitance from 122.1Fg-1 to 142.0Fg-1 after 30% permanent elongation, which is a 22% enhancement. Furthermore, the overall specific capacitance was the highest for the addition of polypyrrole on MnO2 coated CNT-cotton textile 461.0F/g, and the enhancement in reliability and electrochemical performance upon addition of polypyrrole thin film. Our results indicate that the polypyrrole thin film and Ag nanowire network and the simple mechanical pre-straining of the textile fibers contribute to significant enhancements in the electrochemical performance of the supercapacitors.