Sheilla Atieno Odhiambo

Discharge characteristics of poly(3,4-ethylene dioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) textile batteries; comparison of silver coated yarn electrode devices and pure stainless steel filament yarn electrode devices

This paper investigates textile-based energy storage devices fabricated with poly(3,4-ethylene dioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as an electro-active polymer and conductive yarns as the electrodes. The conductive yarns are sewn into a textile substrate and then coated with PEDOT:PSS systematically. Two different sets of devices were made. A comparison of the devices made with silver coated polybenzoxazol filament yarns and the devices made with pure stainless steel filament yarns is performed. The devices were charged and their self-discharge was measured by voltage decay. A study of the influence of charging time on the decay and the effect brought by various load resistors on the voltage decay is also performed. In this research, the devices with electrodes of pure stainless steel filaments yarns performed better than the devices with silver coated yarns; this outcome has been reported as standard by various researchers.

Electrochemical impedance analysis of a PEDOT:PSS-based textile energy storage device

A textile-based energy storage device with electroactive PEDOT:PSS (poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate)) polymer functioning as a solid-state polyelectrolyte has been developed. The device was fabricated on textile fabric with two plies of stainless-steel electroconductive yarn as the electrodes. In this study, cyclic voltammetry and electrochemical impedance analysis were used to investigate ionic and electronic activities in the bulk of PEDOT:PSS and at its interfaces with stainless steel yarn electrodes. The complex behavior of ionic and electronic origins was observed in the interfacial region between the conductive polymer and the electrodes. The migration and diffusion of the ions involved were confirmed by the presence of the Warburg element with a phase shift of 45° (n = 0.5). Two different equivalent circuit models were found by simulating the model with the experimental results: (QR)(QR)(QR) for uncharged and (QR)(QR)(Q(RW)) for charged samples. The analyses also showed that the further the distance between electrodes, the lower the capacitance of the cell. The distribution of polymer on the cell surface also played important role to change the capacitance of the device. The results of this work may lead to a better understanding of the mechanism and how to improve the performance of the device.

Performance of different types of yarn electrodes in PEDOT:PSS charge storage devices

Abstract This chapter explains fundamental research on fabrication of suitable charge storage devices well integrated into textiles for smart textile systems application. The devices were developed from cotton/polyester fabric as the textile substrate, three different types of conductive yarns as yarn electrodes, and polyethylene dioxythiophene:polystyrene sulfonate (PEDOT:PSS) as the electrolyte. The developed devices are lightweight, flexible, reliable, and well integrated within the textile material. The devices were charged and their discharge recorded in terms of voltage decay. Despite the self-discharge, the devices made with stainless steel yarn electrodes performed better than the ones made with silver-coated and copper-coated yarn electrodes. The charge stored in the devices depended on the charging time to a certain extent. The physics/chemistry behind the charge storage devices is quite complicated. However, the work motivates making of fully integrated electric energy storage in textiles.

Use of electric energy stored in a textile-based PEDOT:PSS capacitor

Flexible capacitors were made using stainless steel yarns as yarn electrodes on textile substrate. The electrolyte material used was a dispersion of polyethylene dioxythiophene (PEDOT) : polystyrene sulphonate (PSS). After charging the capacitor for sufficient time, a sharp voltage drop was observed initially for a few seconds, then the voltage discharge slows down. It was not easy to establish the energy stored in the capacitor due to the self-discharge, however the capacitor could be used to power a TOSHIBA LC-810 calculator for 37. seconds.