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.

Conductive polymer PEDOT:PSS, sandwiched between two conductive yarns, has been proven to have capacitive behavior in our textile energy storage devices. Full understanding of its underlying mechanism is still intriguing. The effect of the PEDOT to PSS ratio and the configuration of the electrode yarns are the focus of this study. Three commercial PEDOT:PSS yarns, Clevios P-VP-AI-4083, Ossila AI 4083, and Orgacon ICP 1050, as well as stainless steel and silver-coated polybenzoxazole (Ag/PBO) yarns, in various combinations, were used as solid electrolytes and electrodes, respectively. Analyses with NMR, ICP-OES, TGA, and resistivity measurement were employed to characterize the PEDOT:PSS. The device charge-discharge performance was measured by the Arduino microcontroller. Clevios and Ossila were found to have identical characteristics with a similar ratio, that is, 1:5.26, hence a higher resistivity of 1000 Ω.cm, while Orgacon had a lower PEDOT to PSS ratio, that is, 1:4.65, with a lower resistivity of 0.25–1 Ω.cm. The thermal stability of PEDOT:PSS up to 250 °C was proven. Devices with PEDOT:PSS having lower conductivity, such as Clevios P-VP-AI-4083 or Ossila AI 4083, showed capacitive behavior. For a better charge-discharge profile, it is also suggested that the PEDOT to electrode resistance should be low. These results led to a conclusion that a larger ratio of PEDOT to PSS, having higher resistivity, is more desirable, but further research is needed.

The photocatalytic decolorization and degradation of an anthraquinone-based reactive dye, C.I. Reactive Blue 19, was carried out in laboratory-scale experiments with the systematic variation of several operational parameters, including electron acceptor (hydrogen peroxide) concentration, initial pH, use of buffer solution, aeration, and the specific chemical nature of the buffer solution. Photodegradation was performed under simulated natural light, and conditions were chosen to mimic those found in industry. Mineralization and decolorization were monitored by UV-vis spectroscopy and total organic carbon analysis, and kinetics were modelled using an in-series first-order combination mechanism. Reaction products were examined and monitored by high-resolution mass spectrometry. Under the conditions explored, the reaction rate was found to depend not only on pH and electron acceptor concentration, but also on the specific chemical nature of the buffer used.

Purpose: The purpose of this paper is to develop a capacitor fully integrated into a wearable textile fabric for the application on smart clothing. Design/methodology/approach: A small capacitor with stainless steel yarns as the electrodes and poly-(3,4–ethylenedioxythiophene): polystryrene sulphonate (PEDOT:PSS) as the dielectric material has been made, integrated into a textile fabric. The electric performance of the capacitor was analyzed and compared with other kinds of electric capacitors. Findings: The fabricated small, PEDOT:PSS capacitor could finally power a calculator for 37 s with the energy stored in it. Originality/value: This finding is of an important significance for a further development on the capacitor with a better performance.

Unusual noisy discharge profiles were observed from some of our textile-based energy storage devices having asymmetrical electrodes consisting of pure stainless steel and silver-coated polybenzoxazole yarns. Our hypothesis was that it was due to the ionic shot noise behavior that occurred in electrochemical devices and is a well-known phenomenon in electronic devices. The poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) polymer coverage on the cell surface, which functioned as a solid electrolyte in this system, was believed to play an important role. To confirm this assumption, devices made with different drop-coating strategies to obtain thin and thick layers of PEDOT:PSS polymer on the cell surface were prepared. The noisy discharge profiles were observed from devices with thin polymer layers, while those with thick layers exhibited normal discharge profiles. The morphology of cell surfaces was characterized by a stereo microscope. Cross-section analysis of a device with a thick layer was employed to further characterize its film formation and elemental properties using Scanning Electron Microscopy-Electron Dispersive Spectroscopy. Formation of multilayers of PEDOT:PSS polymer on the cell surface allowed a continuous interaction between electrode metals and PEDOT:PSS ions at the interface area. The noisy component was caused by the movement of silver ions hopping from one trap to the next. A qualitative model of the autocorrelation function executed to the data with noisy behavior further confirmed the ionic shot noise phenomenon.