Fabrication Of Electrodes Research Articles

Fabrication of the carbon paste electrode modified with Trametes versicolor laccase immobilized on carboxyl functionalized multi-walled carbon nanotubes and its application for measurement of dopamine.

Dopamine (DA) shows numerous roles in a wide range of physiological and pathological processes. In this study, an immobilized laccase-derived biosensor was developed for DA detection. The carboxyl functionalized multi-walled carbon nanotubes (MWCNTs-COOH) was applied for immobilization of laccase from Trametes versicolor (TvLac). According to Plackett-Burman statistical design, the optimum conditions showed at 5 mg/mL of MWCNTs-COOH, 25 mM phosphate buffer (pH 6.0), sonication time for 15 min, 2.5 U/mg of enzyme concentration, immobilization time for 4 h at 4 °C, and rotation at 100 rpm. At these conditions, the experimental and predicted specific activities were 14.19 ± 1.41 U/mg and 13.99 ± 1.54 U/mg, respectively. The activity of immobilized TvLac was >90 % at 60 °C and pH 7.0 as well as after 10 sets of uses. The carbon paste electrode (CPE) modified with the immobilized TvLac was then fabricated, characterized and applied as a biosensor (TvLac@MWCNTs-COOH/CPE) for determination of DA. The mean of diffusion coefficient for DA was considered to be 9.1 × 10-6 cm2/s. The TvLac@MWCNTs-COOH/CPE represented a linear dynamic range of 0.005-100.0 μM with detection limit of 1.0 nM. The TvLac@MWCNTs-COOH/CPE might be introduced as a suitable sensor for monitoring of DA in real specimens which merit further studies.

Fabrication of a 3D-printed electrode applied to electrochemical sensing of lamotrigine (LTG)

A novel miniature 3D-printed electrode featuring a working area made from conductive filament, with the electrode body formed through resin injection and UV curing is described. To enhance the conductivity and electrochemical performance, the electrode surface was laser ablated, and modified with graphene oxide (GO), and thorn-like gold nanostructure (TLGNS). The electrode was then utilized for the sensitive detection of lamotrigine (LTG), an important anti-epilepsy drug, using chronoamperometry. This method yielded a linear detection range from 0.01 nmol L−1 to 300 µmol L−1, a limit of detection (LOD) of 0.01 nmol L−1, and a limit of quantification (LOQ) of 0.05 nmol L−1. Additionally, the electrochemical sensor demonstrated excellent intra-sensor reproducibility, with a relative standard deviation of 1.5% (n=9, single sensor).

A Quantitative Method to Guide the Integration of Textile Inductive Electrodes in Automotive Applications for Respiratory Monitoring

Abstract: Induction-based breathing sensors in automobiles enable unobtrusive respiratory rate monitoring as an indicator of a driver’s alertness and health. This paper introduces a quantitative method based on signal quality to guide the integration of textile inductive electrodes in automotive applications. A case study with a simplified setup illustrated the ability of the method to successfully provide basic design rules about where and how to integrate the electrodes on seat belts and seat backs to gather good quality respiratory signals in an automobile. The best signals came from the subject’s waist, then from the chest, then from the upper back, and finally from the lower back. Furthermore, folding the electrodes before their integration on a seat back improves the signal quality for both the upper and lower back. This analysis provided guidelines with three design rules to increase the chance of acquiring good quality signals: (1) use a multi-electrode acquisition approach, (2) place the electrodes in locations that maximize breathing-induced body displacement, and (3) use a mechanical amplifying method such as folding the electrodes in locations with little potential for breathing-induced displacement.

Highly Selective Electroreduction of Carbon Dioxide Using Defect-Driven Catalysis.

The production of methanol from the electrochemical reduction of CO2 is a promising method of mitigating climate change while simultaneously producing a useful liquid fuel. In this study, we design self-assembled monolayers (SAMs) of thiols on metal and metal oxide electrodes that operate via cooperative catalysis between the thiolated surface sites and exposed electrode defect sites. This defect-driven mechanism enables the fabrication of SAM-modified ZnO electrodes that yield methanol with an extraordinarily high Faradaic efficiency of up to 92%. To understand the origin of this high selectivity, we study the effect of the chain length of the alkanethiols, different tail functional groups, and applied voltages on catalyst performance. These results combined with density functional theory calculations give a detailed atomic-level understanding of catalyst operation. Furthermore, the SAM linkage tolerates CO2 reduction conditions, and the catalyst's excellent selectivity for methanol remains high after 10 h of continuous conversion. Taken together, these findings with SAM-based electrodes convey a new and facile design strategy for the creation of highly selective CO2 reduction electrocatalysts.

The Use of Textile Electrodes for Electrical Resistivity Tomography in Periglacial, Coarse Blocky Terrain: A Comparison With Conventional Steel Electrodes

The Use of Textile Electrodes for Electrical Resistivity Tomography in Periglacial, Coarse Blocky Terrain: A Comparison With Conventional Steel Electrodes

Advancing Human–Machine Interface (HMI) through Development of a Conductive‐Textile Based Capacitive Sensor

AbstractSmart wearable sensors in human–machine interfaces (HMI) facilitate communication and interface between humans and robots, as well as among humans. Conventional wearables face significant limitations, including performance degradation under various deformations (e.g., strain and pressure), limited stretchability and flexibility, poor comfort, and breathability, complicating their integration into HMI applications. In response to these limitations, a smart, sewable, high‐precision HMI device based on a soft, textile‐based sensor with machine learning (ML)‐assisted data processing is proposed. The (Ag)‐based fabric electrode integrated into polymeric composite dielectric layer, exhibiting hysteresis error of (≤4%), a tensile strain sensitivity of gauge factor (GF) ≃ 1.03 at 100% elongation, a pressure sensitivity of ≈1.583 × 10−2 kPa−1 at pressures (<50 kPa) and excellent stability (>1000 cycles). To demonstrate its versatility in HMI, the textile‐based sensor is integrated into a glove for real‐time control of a commercially available prosthetic hand and a drone, as well as for sign language recognition, achieving 95.4% classification accuracy using the random forest (RF) classifier across 10 gestures. Beyond gesture recognition, the sensor measures a range of subtle physiological activities (>0.35 kPa), functioning as a force myograph, esophageal manometry, and in gait analysis, among other strain and pressure‐related applications, highlighting exceptional capabilities for advanced wearable systems.

Application and evaluation knitted electrodes for body signal measurement using adhesive intermediate electrode

Textile electrode is capable of measuring the myoelectric potentials of skeletal muscles such as electromyography (EMG), owing to their outstanding low weight, flexibility, breathability, and comfort properties. Nonetheless, textile surfaces often exhibit intermittent adhesion between the electrode surface and the skin, which can result in fluctuations in electrical resistivity due to the inherent characteristics of textiles. This study aimed to suggest the solutions to improve adhesive of textile electrode for the improvement of electrode performance with high quality signal by minimizing these intermittent contacts. For this, an adhesive intermediate, two different conductive materials, between the skin and the textile electrode was introduced to improve the instability skin contact, respectively. To assess the impact of various adhesive intermediates on knitted electrodes, two different types of adhesive intermediates were utilized: a conductive hydrogel-based adhesive intermediate and a conductive paste-based adhesive intermediate. Moreover, the durability of knitted electrodes with adhesive intermediate was evaluated by assessing the changes of signal quality during drying time for 180 min. As a results of sEMG measurement, it was confirmed that the sEMG signal was stably detecting by applying the adhesive intermediate. Both types of adhesive intermediate significantly increased the signal acquisition performance of knitted electrodes by more than threefold. After five washing cycle, the knitted electrodes with two types of adhesive intermediate maintained approximately 80% of their initial SNR values. Therefore, the use of the adhesive intermediate presented in this study not only improves the performance of the electrode but also ensures reusability.

Breaking Activity‐Durability Inverse Relationship via Electrode Engineering by Utilizing β‐MnO2/RuO2 Heterostructures for Efficient Seawater Electrolysis

AbstractSignificant efforts are underway to enhance the efficiency of water electrolysis for sustainable hydrogen production. Approaches that were explored are the design of an efficient anode, engineering of electrolytes, and application of diffusion protective layer over the catalyst to protect it from corrosive reactions. Here we are exploring the engineering of electrode fabrication to enhance the efficacy of anode catalysts by ensuring that the materials are carefully selected. β‐MnO2 has been used to develop a cost‐effective method for electrode fabrication that establish a Schottky junction at heterostructure interface. This method transforms commercial RuO2, which is considered to be less active and stable, highly selective for chlorine oxidative reactions, into a highly active, stable, and OER‐selective in alkaline medium and surrogate seawater. With the help of thorough electrochemical techniques, we found that this engineering significantly improves the effective electrochemical surface area, and higher kinetics and conversion per unit site, profoundly affecting the charge transfer mechanism and optimizing the adsorption of OER intermediates, resulting in much‐increased mass activity. It is observed that the selectivity of the OER was enhanced due to the Lewis acid repercussions of β‐MnO2.

Enhancing activated carbon supercapacitor electrodes using sputtered Cu-doped BiFeO3 thin films

This work describes the fabrication of a composite supercapacitor electrode made of Cu-doped BiFeO3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$_3$$\\end{document} (Cu-BFO) films on an activated carbon (AC) electrode using radio-frequency (RF) magnetron sputtering. To prevent exfoliation of Cu-BFO and AC upon immersion in an electrolyte, the nickel foam sandwiching electrode technique was introduced. The Cu-BFO films significantly enhanced electrochemical properties, increasing specific capacitance by up to 151% compared to that of an AC electrode. This was attributed to Faradaic reactions and specific surface area in the Cu-BFO/AC electrode. The highest specific capacitance achieved was 169 F g-1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\hbox {g}^{-1}$$\\end{document} at 0.5 A g-1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\hbox {g}^{-1}$$\\end{document} , and cycling stability retention was 93.12% after 500 cycles. However, the remaining percentage of the specific capacitance decreased differently with increasing thickness, which is also discussed. Furthermore, an asymmetric supercapacitor using Cu-BFO/AC and AC electrodes demonstrated a high energy density of 4.71 Wh kg-1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\hbox {kg}^{-1}$$\\end{document} , power density of 2.66 kW kg-1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\hbox {kg}^{-1}$$\\end{document}, and over 90% retention after 1000 cycles, highlighting its durability. The uniform RF magnetron sputtering deposition is vital for mass production. Combined with impressive retention in asymmetric supercapacitors, this scalability suggests a promising pathway for large-scale manufacturing. Consequently, this work could pave the way for the large-scale production of supercapacitors.

Fabrication of High-Performance Neural Stimulation Electrode through Pulsed Electrochemical Deposition of IrOx onto Nano-Porous Platinum

Abstract Electrodes for neural stimulation are pivotal in medical and brain science applications. This study aims to prepare novel neural stimulating electrodes with enhanced electrochemical performance and improved mechanical stability through a two-step electrochemical deposition process. Initially, a highly porous platinum (Porous-Pt) electrode with high nanoscale roughness is fabricated, followed by the incorporation of IrOx onto the Porous-Pt surface. The resulting IrOx/Porous-Pt electrode combines the advantages of both materials, offering low impedance, significantly increased CIC, and improved mechanical stability. Scanning electron microscopy revealed that the porous surface of the electrode consisting of sphere-shaped Pt nanoparticles offers a significant effective surface area, promoting strong adhesion and stability for uniform IrOx deposition onto Porous-Pt. This characteristic contributed to the long-term mechanical stability of the IrOx/Porous-Pt electrode.

Self-limited and reversible surface hydration of Na2Fe(SO4)2 cathodes for long-cycle-life Na-ion batteries

Air stability is a crucial factor in the practical application of a battery material, as it profoundly affects the material's preparation, storage, and electrode fabrication processes. Sodium iron sulfate cathodes, despite their attractive attributes in cost and electrochemical performance, are widely believed to be unstable upon air exposure because of the sulfate group. Here we report remarkable air-stability of the Na2Fe(SO4)2-based (NFS) cathodes (minimal decay in 20 % RH air for 60 days, 91.9 % capacity retention after 3500 cycles in half cells) and their outstanding cycle performance in practically relevant pouch-type full cells (∼100 Wh kg-1 specific energy, >1000 cycle-life). Although the NFS cathodes do react with moisture H2O to produce Na2Fe(SO4)2⋅4H2O but the hydration is spatially confined at the NFS particles’ surface and not propagating into their bulk. Further, the structural changes are reversible when the surface-hydrated NFS particles are heated in the typical electrode vacuum-drying process, avoiding extra treatment and additional cost. This work reveals the promising properties of the NFS cathode materials towards high-performance and sustainable Na-ion batteries.

Side-Reactions of Polyvinylidene Fluoride and Polyvinylidene Chloride Binders with Aluminum Chloride-Based Ionic Liquid Electrolyte in Rechargeable Aluminum-Batteries

Rechargeable aluminum batteries (RABs) use a Lewis acidic aluminum chloride (AlCl3) and 1-Ethyl-3-methylimidazolium chloride (EMImCl) ionic liquid electrolyte. Electrode fabrication often relies on procedures from lithium-ion batteries (LIBs), including the use of Polyvinylidene fluoride (PVdF) as a binder. However, PVdF reacts with Al2Cl7 − in the RAB electrolyte, making it unsuitable for new battery types. The literature lacks details on the products formed, changes in the ionic liquid electrolyte, and the implications for electrochemical performance. With potential European Chemical Agency restrictions on per- and polyfluoroalkyl substances (PFAS) by 2025, Polyvinylidene chloride (PVdC) is being explored as an alternative binder. In contact with AlCl3:EMImCl (1.50:1.00) electrolyte, both, PVdF and PVdC transform into amorphous carbon during dehydrofluorination and dehydrochlorination, respectively, as confirmed by Raman spectroscopy. Furthermore, via 19F-NMR, it is shown that the reaction time between the soaked polymers and the ionic liquid has a significant influence on the newly formed aluminum chlorofluoride complexes. Electrochemical tests of graphite-based electrodes indicate increasing specific capacity of PVdF compared to PVdC with a continuous number of cycles. Amorphous carbon can prevent the disintegration of graphite and enhance conductivity. Furthermore, newly formed AlF4 − can run a co-intercalation and lead to increasing specific capacity.

Porous activated carbon electrodes derived from Eleusine coracana biowaste in electric double layer capacitors: Nanoarchitectonics and performance

The development of high-performance supercapacitors from biowaste is crucial for advancing sustainable and renewable energy storage technologies. In this study, we report the fabrication of electrodes for high-performance supercapacitors using porous carbon derived from red millet (Eleusine coracana) straw. Porous carbon was synthesized via a two-step chemical activation process using KOH, resulting in a hierarchical pore structure comprising macro-, meso-, and micropores. The red millet-based porous carbon electrodes, assembled in a two-electrode symmetrical supercapacitor, exhibited a specific capacitance of 68 Fg⁻1 at a current density of 0.5 Ag⁻1 in a 1 M Na₂SO₄ aqueous electrolyte. At a mass loading of 5 mg per electrode, the system demonstrated a specific capacitance of 300 Fg⁻1 at 1 Ag⁻1, with an energy density of 9.1 Whkg⁻1 and a power density of 1.86 kWkg⁻1, as determined from galvanostatic charge-discharge measurements. Additionally, the supercapacitor showed excellent cyclic stability, retaining 98.78% of its initial capacitance after 5000 cycles at 10 Ag⁻1. These findings highlight the potential of porous carbon derived from agricultural biowaste for scalable applications in electric double-layer capacitors.

Silver‐Copper Oxide Core‐Shell Nanoparticles/β‐Cyclodextrin Functionalized Single‐Walled Carbon Nanotubes Based Electrochemical Sensor for 4‐Chloro‐3‐Methylphenol Detection

AbstractChlorophenols are high‐priority organic pollutants that harm the environment and human health. Therefore, it is crucial and urgent to detect and quantify chlorophenols in the environment selectively and sensitively. For this, the introduction of smart nanomaterials to create electrochemical sensors is a noteworthy development. In the present article, a glassy carbon electrode was fabricated by Agcore‐CuOshell nanoparticles (Ag@CuO) and β‐cyclodextrin functionalized single‐walled carbon nanotubes (β‐CD‐fSWCNT) through drop‐casting method (Ag@CuO‐β‐CD‐fSWCNT‐nafion‐GC) and applied for the selective and sensitive detection of chlorophenols, particularly 4‐chloro‐3‐methylphenol (CMP). The Ag@CuO nanoparticles with core‐shell configuration were synthesized and characterized by using various analytical techniques like UV–vis spectroscopy, X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), high‐resolution transmission electron microscopy (HR‐TEM), selected area electron diffraction pattern (SAED), and energy dispersive X‐ray spectroscopy (EDS). The electrode fabrication steps were monitored and confirmed by using field‐emission scanning electron microscopy (FE‐SEM), attenuated total reflectance – Fourier transform infrared spectroscopy (ATR‐FTIR), and cyclic voltammetry (CV) studies. The electrochemical sensing of CMP was done by using differential pulse voltammetry (DPV) and the results showed that the peak current is linear with increasing concentration in the range of 10–50 µM at the modified electrode. The detection limit of 1.4 nM (S/N = 3) was obtained with a correlation coefficient of 0.998. The electrode showed good reproducibility with a relative standard deviation (RSD) of 1.56% and sensitivity of 15.67 µAcm−2µM−1 toward CMP. The sensor showed anti‐interference properties and long‐term stability. The real sample analysis results indicated that the sensor electrode could be used to detect low concentrations of CMP in wastewater with a recovery of 103.3% and has good potential for use in practical applications.

Development of Graphene Coated Wearable Electronic Textiles for Biomedical and Health Monitoring Devices

Graphene-based highly, conductive, flexible, washable, and breathable textile electrodes have been developed using the pad-dry-cure method. It is found that the electrical conductivity of the graphenecoated textile electrodes was significantly improved by padding process.

Fabrication of Flat-Interface Nerve Electrodes for Recording Neural Activity

Fabrication of Flat-Interface Nerve Electrodes for Recording Neural Activity

Fabrication of Flat-Interface Nerve Electrodes for Recording Neural Activity

Fabrication of Flat-Interface Nerve Electrodes for Recording Neural Activity

Fabrication of a disposable electrode based on recordable gold compact disc modified with Bi-Bi2O2CO3@ graphitic carbon nitride nanocomposite for the simultaneous detection of mesalazine and uric acid in biological fluids

A homemade disposable gold electrode was fabricated from gold compact disc (Au-CDs) and modified with Bi-Bi2O2CO3@g-C3N4 nanocomposite for the simultaneous detection of mesalazine (5-amino salicylic acid; 5-ASA) and uric acid (UA) in aqueous solutions. The Bi-Bi2O2CO3@g-C3N4 nanocomposite was characterized by Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, field emission scanning electron microscopy and photoluminescence spectroscopy. The analytical response of the modified g-CDs electrode towards 5-ASA and UA was evaluated by cyclic voltammetry and differential pulse voltammetry. Under optimal conditions, the modified g-CDs electrode was able to detect 5-ASA and UA in the concentration ranges of 1.0–160 µmol L−1 and 10–190 µmol L−1 with detection limits of 0.65 µmol L−1 and 3.07 µmol L−1 for 5-ASA and UA, respectively. The prepared Bi-Bi2O2CO3@g-C3N4 nanocomposite exhibited high sensitivity and selectivity towards 5-ASA and UA in urine and plasma samples with recoveries in the range of 91.0 % - 109.3 %.

Scattering-Free and Fast Response Polymer Brush-Stabilized Liquid Crystals Beam Steering Using Surface-Initiated Polymerization Technique.

Nonmechanical fast response optical beam steering technology is increasingly essential for telecommunications, imaging systems, optical sensing, displays, and military applications. Polymer network liquid crystal (PNLC) beam steering can achieve submillisecond response times but faces limitations due to scattering issues arising from the refractive index mismatch between the polymer network and the liquid crystals (LCs). In this article, we demonstrate a scattering-free, fast-response LC beam steering by using polymer brushes to stabilize the gradient refractive index. First, the initiator is incorporated into the alignment layer and the monomer is mixed into the LC layer. Surface-initiated polymerization (SIP) is then employed to grow the polymer brushes exclusively on the substrate's surface, thus confining the polymer network's growth to the LC bulk and reducing interfacial scattering. For polymer brush stabilized liquid crystal (PBSLC) beam steering device with a period size of 225 μm and a cell gap of 7.2 μm, the average transmission rate reaches 88% in the visible light spectrum with a haze value of only 6.91. The steering angle is 0.16, and the diffraction efficiency is 80.3%. When a voltage of 35 Vrms is applied, the primary energy can be tuned to the zeroth order, with a response time close to 1 ms. By cascading two PBSLC beam steering devices with opposite steering directions, the primary energy of the beam can be adjusted between zeroth, +1, and -1 order. This method requires only a UV light source, a precision displacement stage, a power supply, and a mask, avoiding the need for expensive equipment and complex electrode fabrication. By adjustment of the phase change period, step width, and number of steps during fabrication, the steering angles and diffraction efficiency of the PBSLC beam steering device can be easily controlled, highlighting its significant potential for industrial production.

Advances and Challenges of Carbon‐Free Gas‐Diffusion Electrodes (GDEs) for Electrochemical CO2 Reduction

AbstractElectrochemical CO2 reduction reaction (CO2RR) coupled with renewable electricity holds promises for efficient mitigation of carbon emission impacts on the environment and turning CO2 into valuable chemicals. One important task in CO2RR development is the design and fabrication of efficient electrodes for stable operation in the long term. Gas‐diffusion electrodes (GDEs) have been employed to continuously feed CO2 to the electrolyzers. Despite significant advances in GDE design and tailoring GDE properties, the present GDEs often suffer from the critical issue of flooding due to the electrowetting of carbon‐based substrates, which hinders the transition to industrial application. To address flooding, GDEs with intrinsically hydrophobic polymeric substrates have been recently fabricated and have shown promising performances. Herein, the advances and challenges associated with carbon‐free GDEs are reviewed for CO2RR. This review first briefly outlines GDE and electrolyzers basics. Through critical discussion around the shortcomings of conventional carbon‐based GDEs, the most recent efforts to resolve flooding are summarized. Subsequently, the advances, advantages, and challenges of carbon‐free GDEs are elaborated. Finally, priorities for future studies are suggested, with the aim to support the advancement and scale‐up of carbon‐free GDEs and extend them to other electrochemical systems where gas and the electrolyte are in contact.