Cotton Electrode Research Articles

Synthesis of MXene-based nanocomposite electrode supported by PEDOT:PSS-modified cotton fabric for high-performance wearable supercapacitor

The rapid development of wearable and portable electronic devices prompts the ever-growing demand for wearable, flexible, and light-weight power sources. In this work, a MXene/GNS/PPy@PEDOT/Cotton nanocomposite electrode with excellent electrochemical performances was fabricated using cotton fabric as a substrate. Poly (3,4-ethylenedioxythiophene): poly (styrenesulfonate) (PEDOT:PSS) was coated on the cotton fabric to obtain a conductive substrate through a controllable dip-drying coating process, while a nanocomposite consisting of MXene, Graphene nanoscroll (GNS), and polypyrrole (PPy) was directly synthesized and deposited on the PEDOT:PSS-modified cotton fabric via a one-step in situ polymerization method. The resultant MXene/GNS/PPy@PEDOT/Cotton electrode delivers excellent electrochemical performances including an ultra-high areal capacitance of 4877.2 mF·cm−2 and stable cycling stability with 90 % capacitance retention after 3000 cycles. Moreover, the flexible symmetrical supercapacitor (FSC) assembled with the MXene/GNS/PPy@PEDOT/Cotton electrodes demonstrates a prominent areal capacitance (2685.28 mF·cm−2 at a current density of 1 mA·cm−2) and a high energy density (322.15 μWh·cm−2 at a power density of 0.46 mW·cm−2). In addition, the application of the FSC for wearable electronic devices was demonstrated.

Screen printed textile electrodes using graphene and carbon nanotubes with silver for flexible supercapacitor applications

The eco-friendly conductive cotton textile is promising alternatives for the flexible substrates in wearable devices since the cotton is as an inexpensive natural fabric material and compatible in modern portable electronics with adequate electrical conductivity. In this work, flexible conductive cotton-based electrodes are prepared via a screen-printing method using the carbonaceous nanomaterials such as carbon nanotubes (CNTs) and graphene with an additional component of conductive silver (Ag) powder and textile ink. The prepared conductive cotton electrodes exhibit lower sheet resistance (<10 Ω) along with superior mass loading (20-30 mg.cm-2). On the basis of the performance of cotton electrodes prepared, an all-solid-state flexible supercapacitor device was successfully fabricated which exhibits a high specific areal capacitance of 677.12 mF.cm-2 at 0.0125 mA.cm-2 for a suitable electrode composition (60% of Ag and 40% CNTs) using a PVA-KOH gel electrolyte. The flexible device endures a stable electrochemical performance under severe mechanical deformation using different bending angles (0°, 30°, 45°, 60° and 90°) of the device and possesses excellent cyclic stability with the capacitance retention of ~80% even after 3000 CV cycles.

Textile-based electrode for electrocardiography monitoring

The increasing demand of smart garment for monitoring people’s health is due to comfortability, lightweight and flexibility properties of the textile could offer to the user. The textile-based electrocardiography (ECG) electrode is an alternative of commercially available silver/silver chloride (Ag/AgCl) electrode which could cause skin allergies to certain users and is not suitable for long-term monitoring electrode. In this paper, we report the performance of reduced graphene oxide (rGO) coated cotton fabric electrode to the effect of longevity and temperature. The ECG waveform and signal-to noise ratio (SNR) of the rGO-coated cotton electrodes were compared to that the performance of Ag/AgCl electrodes. The reliability characterization confirmed the rGO-coated cotton fabric conductance maintain at more than 80% even after 100 days of fabrication and the conductance measurement is increasing with respect to the temperature applied. The electrode shows lower in impedance value and the performance in acquiring ECG signal is comparable with the Ag/AgCl electrode. The vertical position rectangle-shaped electrode is recommended in measuring ECG signals. In conclusion, the rGO-coated cotton electrode with flexible dry-type electrode and excellent performance especially reliability and in capturing ECG signal had shown a promising result for further development.

Optimization of Reduced GO-Based Cotton Electrodes for Wearable Electrocardiography

The quality of Electrocardiography (ECG) signal is dependent on the electrode's performance. Comfort and long-term monitoring are the main benefits of a dry and flexible electrode compared to conventional silver/silver chloride (Ag/AgCl) electrode. The main objective of this study is to develop high performance textile-based electrode by optimising fabrication method and electrode design. Cotton fabric was dipped into graphene oxide (GO), followed by reduction process to form reduced graphene oxide-cotton (rGOC), where L-ascorbic acid (C6H8O6) was used as the reducing agent. Conductivity and skin-electrode interface impedance of the fabricated cotton were characterized using Four-point probe (Van der Pauw) and Potentiostat, respectively. This study focuses on the investigation of electrode design that includes fabrication methods, electrode sizes and shapes. The performance of the reduced GO-based cotton (rGOC) electrode in terms of ECG signal quality was compared to conventional Ag/AgCl electrode and metal clamp under static and dynamic wearable conditions. Results from the conducted experiments show that the fabricated electrode's performance is influenced by dipping time and electrode design, with circle-shape electrode shows the highest conductivity (up to 9k S/m at 1 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> area) compared to square- and rectangular-shape electrodes (<; 8k S/m and 14.55 S/m, respectively, at 1 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> area). The circle-shape rGOC electrode's performed better (SNR 14.85±0.22 dB) than Ag/AgCl electrode (SNR 11.26±0.18 dB) and metal clamp (SNR 12.28±0.72 dB) in capturing static ECG signal. A wearable circle rGOC electrode with 1.7 cm radius performed also similarly under static (SNR 32.60±0.72 dB) and dynamic (SNR 30.27±1.37 dB) ECG monitoring, respectively.

Effects of three fabric weave textures on the electrochemical and electrical properties of reduced graphene/textile flexible electrodes.

Textile textures formed through woven, knitted or nonwoven weaving technology have critical effects on the electrical and electrochemical properties of flexible electrodes. Therefore, the effects of textile structures, including porosity and pore configuration, on the loading amount of reduction graphene (RGO), the electrical and electrochemical properties were systematically studied. The results show that knitted fabric had the highest mass loading of RGO sheets and lowest sheet resistance among these three fabrics. However, the specific capacitance of woven fabric was optimum 40.5 F g−1 at a scan rate of 5 mV s−1 within the voltage window of 0–0.8 V, which was ascribed to its suitable porosity and pore size firmly anchoring the RGO sheets. Also, the RGO/woven cotton electrodes exhibited good cycling stability and excellent electrochemical stability without an obvious loss in the capacitive performance. The above results provide a theoretical basis for the selection of textile substrates for high-performance flexible electrodes.

Functionalization of textile cotton fabric with reduced graphene oxide/MnO2/polyaniline based electrode for supercapacitor

In this work, a new cotton electrode has been synthesized by coating ternary materials of reduced graphene oxide (rGO), manganese dioxide (MnO2), and polyaniline (PANi) on textile cotton fabric. First, Graphene oxide was deposited on cotton fibers by a simple ‘dip and dry’ method and chemically reduced into rGO/cotton fabric. MnO2 nanoparticles were accumulated on rGO/cotton fabric by in situ chemical deposition method. PANi layer was coated on rGO/MnO2/cotton fabric by in situ oxidative polymerization technique. A thin PANi coating layer acts as a protective layer on rGO/MnO2/cotton fabric to restrain MnO2 nanoparticles and rGO from dissolution in H2SO4 acidic electrolyte. The specific surface area of cotton electrode was measured using the Brenauer-Emmett-Teller (BET) method. The cyclic voltammetry (CV) results show that the cotton electrode has good capacitive behavior. The ternary cotton electrode exhibits high specific capacitance values of 888 F g−1 and 252 F g−1 at a discharge current density of 1 A g−1 and 25 A g−1 in 1 M H2SO4 electrolyte solution. The high areal specific capacitance of 444 Fcm−2 was achieved for as-fabricated electrode. Also, the cotton electrode retains around 70% of specific capacitance after 3000 cycles at charge-discharge current density of 15 A g−1. The slow decrease in specific capacitance is observed with increased discharge current density which proves its excellent rate capability. These results of rGO/MnO2/PANi/cotton fabric electrode show that this can be an excellent electrode for supercapacitor in energy storage devices.

Synthesis of wearable and flexible NiP0.1-SnOx/PANI/CuO/cotton towards a non-enzymatic glucose sensor

Ni-SnOx, PANI and CuO nanoparticles were synthesized on cotton fabric through chemical methods to make a new flexible high-performance non-enzymatic glucose sensor. FESEM, XRD, XPS, EDS and ATR analysis were employed to characterize the structure and the morphology of the nanomaterials. The high electrochemical performance of nickel and copper oxide and hydroxide on a conductive template leads to fabrication of a wearable and flexible cotton electrode with an excellent electrocatalytic activity to oxidize glucose. This hybrid system on the fabric as an electrode indicates a detection limit of 130 nM with wide linear range of 0.001–10 mM. The sensitivity was measured to be 1625 and 1325 μA mM−1 cm−2 for the ranges of 0.001–1 and 1–10 mM, respectively. Long-term stability, appropriate selectivity and reusability for many times make possibility for utilizing the fabricated sensor in the practical applications. The fabric is a wide linear range electrode with low detection limit to sense glucose concentration in the body fluids as well as the human blood that can be presumably suggested for designing other similar flexible types of sensor.

Wash-stable, oxidation resistant conductive cotton electrodes for wearable electronics.

Commercial, untreated cotton fabrics have been directly silver coated using one-step electroless deposition and, subsequently, conformally encapsulated with a thin layer of poly(perfluorodecylacrylate) (PFDA) using initiated chemical vapor deposition (iCVD). The surface of these PFDA encapsulated fabrics are notably water-repellent while still displaying a surface resistance as low as 0.2 Ω cm−1, making them suitable for incorporation into launderable wearable electronics. X-ray photoelectron spectroscopy confirms that the PFDA encapsulation prevents oxidation of the silver coating, whereas unencapsulated samples display detrimental silver oxidation after a month of air exposure. The wash stability of PFDA-encapsulated, silver-coated cotton is evaluated using accelerated laundering conditions, following established AATCC protocols, and the samples are observed to withstand up to twenty home laundering cycles without notable mechanical degradation of the vapor-deposited PFDA encapsulation. As a proof-of-concept, PFDA-Ag cotton is employed as a top and bottom electrode in a layered, all-fabric triboelectric generator that produces voltage outputs as high as 25 V with small touch actions, such as tapping.

Solid‐State Supercapacitor Fabricated in a Single Woven Textile Layer for E‐Textiles Applications

This paper presents for the first time a solid‐state supercapacitor fabricated in just a single woven cotton textile layer. The controlled spray coating process enables the depth of the activated carbon electrodes to be precisely controlled from both sides of the textile. This leaves an uncoated region within the cotton textile layer that acts as the separator and also minimizes the effect of the added functional materials on the feel of the textile. The cotton electrode is then vacuum impregnated with the gel electrolyte to ensure good coverage of the electrode by the electrolyte. After drying, the single textile layer supercapacitor has been fully characterized and demonstrates good capacitance and excellent electrochemical cycling stability even after mechanically straining the textile.

A highly active biomass-derived electrode for all vanadium redox flow batteries

In this work, we report an environmentally friendly and low-cost approach to synthesize an all biomass-derived electrode from cotton through a pyrolysis process and apply this novel electrode to a VRFB for the first time. It is demonstrated that this carbonized cotton (CC) electrode presents a higher BET surface area, a larger number of oxygen-containing functional groups, a better wettability and higher catalytic activity for vanadium reactions than commercial carbon papers (CPs) do. As a result, the CC electrode improves the reversibility toward VO2+/VO2+ by 100mV lower peak separation as compared with commercial CPs. Moreover, the VRFB assembled with the prepared electrodes delivers a high voltage efficiency of 75.4% at a current density of 100mAcm−2, outperforming the oxidized CPs (68.3%), and a better rate performance during the charge-discharge test at various current densities. These results suggest that the carbonized cotton electrode offers a great promise for the large-scale application in VRFBs.

Simple and Efficient: Validation of a Cotton Wick Electrode for Animal Electroretinography

Purpose: Electroretinography (ERG) is a widely used technique to test retinal function in humans and animals. Recordings are particularly dependent on the type of electrodes used, with the best electrodes often being expensive and not always easy to use. The need of a simple and effective electrode type has led us to search the efficacy of different types of electrodes used in practice and compare them with the modified cotton wick electrode. Material and Methods: A modified type of electrode made of a cotton wick and impregnated with NaCl is described, and the ERG results were compared with other types of electrodes. Results: Compared with standard metal wire loop electrodes, the cotton wick electrode results in obtaining higher amplitudes, a better inter-eye correlation in the same animal and a better reproducibility of the recordings over time. Conclusion: This cotton electrode is simple to make and easy to place. It provides reliable recordings during the entire life span of the animal and reliable comparisons between contralateral eyes, thus providing a powerful tool for ERG studies.

Electroanesthesia for Military Application

Abstract : The study was conducted to assess the potential usefulness of general electroanesthesia in dentistry. Experimental subjects were rhesus macaque monkeys. Circuitry was designed and constructed to yield a waveform comprised of a high frequency (100 KHZ) pulse train modulated by a low frequency (100 HZ) pulse train. The modulated waveform was applied transcranially through saline-soaked cotton electrodes placed at nasion (cathode) and inion (anode). The current was increased from an initial level of 10 ma (peak) to a maximum of 50 ma (peak) over a 20-minute induction period. Average values of the initial and final currents were 1.0 ma and 5.0 ma, respectively. Induction was accomplished with and without the use of chemical adjuncts. However, medication (phencyclidine hydrochloride 0.5 mg per kg body weight) prior to administration of the current appeared to alleviate discomfort elicited by the low frequency component of the waveform. Conventional restorative, endodontic and oral surgical procedures were accomplished readily at low current levels.