Chloride Electrodes Research Articles

Investigation of electrochemical performance of gadolinium trichloride in asymmetric supercapacitor applications

The commercial Gadolinium tri chloride (GdCl3) electrode material exhibits high specific capacitance of 207.52Fg−1 in three electrode system at 1A/g with potential window 1.0 V. The GdCl3//Activated carbon (AC) asymmetric supercapacitor device in two electrode system achieves 188.14Fg−1 specific capacitance at 1 A/g with high potential window 1.7V. It possess high energy density 75.51Wh/kg, power density 850W/kg. and electrochemical stability of 92% of its initial capacitance after 5000 cycles. These demonstrate GdCl3 as an useful material for electrochemical energy storage devices. Further, electron paramagnetic resonance study on GdCl3 reveals g-factor 1.98 and line width ΔH = 221.8mT.

Label-Free Detection of Waterborne Pathogens Using an All-Solid-State Laser-Induced Graphene Potentiometric Ion Flux Immunosensor.

Waterborne pathogens are harmful microorganisms transmitted through water sources. Early and rapid pathogen detection is important for preventing illnesses and implementing stringent water safety measures to minimize the risk of contamination. This work introduces a miniaturized all-solid-state potentiometric ion flux immunosensor for the rapid and label-free detection of waterborne pathogens. A screen-printed silver/silver chloride electrode coated with a reference electrode membrane and polyurethane as an all-solid-state reference electrode was combined with a solid-state contact ion-selective electrode (ISE). An all-solid-state ISE was constructed on laser-induced graphene by coating it with a cationic marker and a carboxylated poly(vinyl chloride)-based membrane for immobilizing antibodies and controlling ion fluxes through the membrane. Proof-of-concept was achieved by detecting Escherichia coli and Salmonella enterica serovar Typhimurium using the assembled immunosensors within 10 min. The potentiometric response shift attributed to the blocking effect in the ion flux caused by pathogen-antibody interaction corresponded to pathogen concentration, indicating detection limits of 0.1 CFU/mL and working ranges of 0.1-105 CFU/mL. Furthermore, the developed sensors revealed high selectivity and were directly applied in groundwater and tap water without any sample preparation, demonstrating high recovery percentages. The simple operation and elimination of sample preparation are key benefits to further usability of the developed immunosensors for efficient pathogen detection.

The Solid‐State Battery Applicational Technology: Material Characteristics and Charge–Discharge Mechanisms of Iron Chloride Electrodes

ABSTRACTThis study delves into the unique characteristics of an iron chloride cathode with a solid‐state electrolyte (SSE) and the construction of a button cell battery (BT cell) for its evaluation. The iron ions in this system can provide either divalent or trivalent ions, which possess a higher electrical capacity (~200 mAh/g) and competitive advantages. The solid‐state electrolyte materials, iron compounds (chloride, oxide), exhibit high activation in electrochemistry. After the cycle test, the ferric chloride electrolyte transforms into another iron hydroxide compound due to its high activation. The study examines iron, ferric oxide (Fe2O3), and ferrous chloride (FeCl2) as cathode materials and evaluates their impact on the battery. Cyclic voltammetry compares the potential and current values of the redox reactions among the three. Finally, transmission electron microscopy (TEM) explores the ferric chloride layer and iron hydroxide in ferrous chloride. The study focuses on the high electrochemical activity of the iron chloride layer and explores the crystal structure and composition for electrochemical analysis. The findings of this study are crucial for understanding the potential of iron‐ion batteries and the role of iron compounds in improving battery performance.

A Novel Design of an Oral Appliance for Monitoring Electromyograms of the Genioglossus Muscle in Obstructive Sleep Apnea Syndrome.

Obstructive sleep apnea (OSA) is a prevalent source of sleep-disordered breathing. OSA is most commonly associated with dysfunctions in the genioglossus (GG) muscle. In this study, we present the first version of a medical device that produces an electromyogram (EMG) of the GG. The prototype is composed of a (custom-made) 3D-printed mouthpiece. Impressions were taken for the lower arch and scanned with a lab scanner to be converted into digital impressions. ExoCad software was used to design the appliance. Fusion 360 software was then used to modify the design and create tubes to house the electrodes in a bilateral configuration to secure excellent and continuous contact with the GG muscle. Silver-silver chloride electrodes were incorporated within the appliance through the created tubes to produce a muscle EMG. In this preliminary prototype, an EMG amplifier was placed outside the mouth, and isolated electric wires were connected to the amplifier input. To test the design, we ran experiments to acquire EMG signals from a group of OSA patients and a control group in wakefulness. The GG EMGs were acquired from the participants for 60 s in a resting state whereby they rested their tongues without performing any movement. Then, the subjects pushed their tongues against the fontal teeth with steady force while keeping the mouth closed (active state). Several features were extracted from the acquired EMGs, and statistical tests were applied to evaluate the significant differences in these features between the two groups. The results showed that the mean power and standard deviation were higher in the control group than in the OSA group (p < 0.01). Regarding the wavelength during the active state, the control group had a significantly longer wavelength than the OSA group (p < 0.01). Meanwhile, the mean frequency was higher in the OSA group (p < 0.01) at rest. These findings support research that showed that impairment in GG activity continues in the daytime and does not only occur during sleep. Future research should focus on developing the device to be more user-friendly and easily used at home during wakefulness and sleep.

Multi‐material direct‐ink‐writing of silver‐based flexible and highly deformable dry electrocardiogram biopatches

AbstractOf significant interest are three‐dimensional (3D) printed dry electrodes, a departure from traditional wet silver/silver chloride (Ag/AgCl) electrodes. These innovative electrodes not only incorporate 3D printed personalized materials but also eliminate the need for electrolyte gel, which tends to dehydrate over time. Additionally, these electrodes boast unique attributes such as stretchability, deformability, biocompatibility, wearable comfort, and cost‐effective manufacturing. While the advantages of dry electrodes are apparent, their performance optimization encounters challenges related to charge migration, particularly when scaled down to miniaturized dimensions, impacting biosignal detection. This study addresses these challenges by focusing on the development of scalable, stretchable, and highly deformable syringe‐printed dry electrocardiogram (ECG) patches. The approach employs straightforward multi‐material direct‐ink‐writing (DIW) techniques, realizing complete biopatches per print, resulting in a rapid and cost‐effective fabrication process. The achieved printing resolution reaches up to 200 µm, and the conductivity of Ag/AgCl dry electrodes reaches approximately ∼ 5 × 104 S/m. This not only ensures scalability but also expands the applications of metal‐based inks to various soft electronic devices, particularly in low‐resource settings and environments.

Redox behavior of unsubstituted cobalt phthalocyanine in nanostructured Langmuir-Schaefer films

Although the properties of unsubstituted metal tetrapyrroles in solutions have received attention in numerous work, the physico-chemistry of their thin films remains poorly investigated. In this work, we constructed thin films of unsubstituted cobalt phthalocyanine on the surface of quartz plates and indium tin oxide (ITO) electrodes using the Langmuir-Schaefer (LS) and drop casting techniques. In LS films, CoPc species are involved in strong intermolecular interactions, which result in formation of CoPc nanostructures and prominent changes in the ultraviolet-visible spectrum. Electrochemical reduction of CoPc in LS films at −0.9 V (versus silver chloride electrode) results in formation of Co(I) species. In contrast to the highly reactive nature of Co(I)Pc in solution, these species generated in thin films are relatively resistant to dioxygen due to the dense packing of CoPc units. These findings can further the development of CoPc-based resistive sensors utilizing not only common Co(II), but also Co(I) species, which may possess different sensitivity toward analytes.

For chloride electrodes to become truly selective, EQAs schemes need to be detective

For chloride electrodes to become truly selective, EQAs schemes need to be detective

Applications of integrated response surface methodology statistic techniques and artificial neural network‐based machine learning to optimize residual chlorine production and energy consumption

AbstractA multifactor interaction study was performed using the combined response surface methodology and an artificial neural network on the operational parameters and their influence on residual chlorine production. The operating variables, sodium chloride concentration, electrical potential, electrolysis time, and electrode gap, were evaluated over the response, residual chlorine and energy consumption. The results indicated that the optimum value for residual chlorine was 2450 mg/L achieved at an electrical potential of 8.8 V for 25 min in the presence of 25 g/L of sodium chloride and an electrode distance of 1 cm, and the optimum corresponding energy consumption was measured at 21.76 kWh/L. The study reveals that electric potential, sodium chloride concentration, and electrolysis time positively influence residual chlorine production. ANN models showed superior prediction ability compared with RSM models. This suggests electrolysis can be used for active chlorine production from saline solutions, potentially for industrial applications and water disinfection.

Chloride leaching of eucalyptus wood particles by water for pellets production

The impacts of climate change caused by the consumption of fossil fuels have encouraged the reduction of greenhouse gas emissions. The use of forest biomass for the pellets production is an alternative for energy generation. However, the high chloride content present in this forest biomass has caused human health and economic problems, which are factors that restrict the export of pellets. The main objective of this work was to reduce the chloride content in eucalyptus wood intended to produce pellets, by leaching the particles with water. Different parts of the eucalyptus tree (bark, branches, leaves, heartwood and sapwood) were characterized, and the biomass stock was determined. The chloride content determination was carried out using the selective chloride electrode and ion chromatography methods. Leaching was performed using a water/wood ratio of 25, 50, 75 or 100 L kg−1. The higher heating value (HHV) of the bark (18.47 MJ/kg), branches (20.01 MJ/kg) and leaves (22.04 MJ/kg) met the requirements of ISO 17225–2. However, their ash (1.91–4.32 %) and chloride content (0.120–0.627 %) were above what is allowed by the standard. The sapwood showed a higher content of volatile matter, ash and holocellulose, while higher values of HHV, fixed carbon, lignin and extractives content were observed for the heartwood. The chloride content present in heartwood was lower than that of sapwood and did not meet the requirements for ISO 17225–2 (≤0.03 % for B and ≤ 0.02 % for A pellets). In general, particle leaching did not significantly affect the energetic properties of wood. Leaching the particles with the lowest water/wood ratio (25 L/kg) was sufficient to remove chloride ions and meet the requirements of ISO 17225–2.

Chloride electrode composed of ubiquitous elements for high-energy-density all-solid-state sodium-ion batteries

Inexpensive and safe energy-storage batteries with high energy densities are in high demand (e.g., for electric vehicles and grid-level renewable energy storage). This study focused on using NaFeCl4, comprising ubiquitous elements, as an electrode material for all-solid-state sodium-ion batteries. Monoclinic NaFeCl4, expected to be the most resource-attractive Fe redox material, is also thermodynamically stable. The Fe2+/3+ redox reaction of the monoclinic NaFeCl4 electrode has a higher potential (3.45 V vs. Na/Na+) than conventional oxide electrodes (e.g., Fe2O3 with 1.5 V vs. Na/Na+) because of the noble properties of chlorine. Additionally, NaFeCl4 exhibits unusually high deformability (99% of the relative density of the pellet) upon uniaxial pressing (382 MPa) at 298 K. NaFeCl4 operates at 333 K in an electrode system containing no electrolyte, thereby realizing next-generation all-solid-state batteries with high safety. A high energy density per positive electrode of 281 Wh kg−1 was achieved using only a simple powder press.

A smart idea to reject motion artefacts from ECG measurements due to sensor-body impedance

Electrocardiogram (ECG) records the electrical activity of the heart and is the most significant diagnostic indicator of health. The electrical activity propagates towards the skin and is typically measured using gel silver/silver chloride (Ag/AgCl) electrodes. The quality of the measured signal depends on the amplitude of the electrical activity, the conductivity of the tissues and skin, and that of the measuring electrode. Gel electrodes can cause skin irritability and are not suitable for long-term measurements requiring the diagnosis of paroxysmal arrhythmias. Dry electrodes are comparatively comfortable to wear but are highly dependent on body hair, sweating, and movement. Non-contact electrodes on the other hand avoid ohmic contact with the skin by providing a capacitive coupling between the skin and the electrode. They can be easily worn over clothing or can be measured from a distance. However, motion artefact remains the biggest challenge in such systems. This study proposes a novel two-channel circuitry for ECG acquisition along with a mathematical model to mitigate the effect of changing sensor-electrode capacitance in non-contact sensors. This method was modeled and validated at different sensor-electrode positions or air-gaps. The effect of change in mutual and parasitic capacitance between the sensor’s channels, body tissue impedance, and the ratio of the areas of the two channels was also analysed in terms of Signal to Noise Ratio (SNR). The highest SNRs were achieved with smaller air-gaps and higher ratios of channels' areas.

Effects of preparation method on thermoelectric properties of poly(aniline‐co‐3,4‐ethylenedioxythiophene)/SWCNT composites

AbstractComposites of conducting polymer and single‐walled carbon nanotubes (SWCNTs) are attracting great attentions in harvesting low‐grade waste heat. Prefabricated SWCNTs film used as the working electrode was placed at the liquid interface between the inorganic phase (dilute sulfuric acid solution) and the organic phase consisting of dichloromethane (DCM), aniline (ANI), and 3,4‐ethylenedioxythiophene (EDOT), together with a platinum wire (the counter electrode) and a silver chloride (AgCl/Ag) electrode (the reference electrode), to perform electrochemical polymerization of ANI and EDOT at the liquid interface. Thermoelectric (TE) composites of poly(ANI‐co‐EDOT) and SWCNTs were produced. Compared with composites from ultrasonic mixing and coating methods, the 10 wt% SWCNTs‐composites in situ formed in electrochemical polymerization have the highest power factor (PF) of 41.56 ± 3.58 μW m−1 K−2, higher than the PF values of the composites formed by other two methods. The work indicates that the TE properties of ANI‐EDOT copolymer/SWCNT (poly[ANI‐co‐EDOT]/SWCNT) composites prepared by electrochemical polymerization were better than those of the composites obtained by physical mixing the electrochemically synthesized poly(ANI‐co‐EDOT) with SWCNTs. Moreover, SWCNTs treated with sodium dodecylbenzene sulfonate (SDBS) could further improve the TE properties of the composites.

Simulated solar-driven photo-assisted anodic oxidation of sulfadiazine by C3N4 modified Ti3+ self-doping TiO2 nanotube arrays

In this study, a C3N4 modified Ti3+ self-doping TiO2 nanotube arrays (C3N4-Ti3+/TiO2-NTA) material was innovatively fabricated using a three-step procedure consisting of anodization, chemical vapor deposition, and in-situ cathodic polarization. Simultaneously introducing C3N4 and Ti3+ significantly enhanced the light absorption property and charge separation efficiency of TiO2-NTA, while also increasing the oxygen evolution overpotential to 2.61 V vs the silver/silver chloride electrode. C3N4-Ti3+/TiO2-NTA with excellent optoelectronic properties was first applied as an anode in the simulated solar-driven photo-assisted anodic oxidation (PAO) system. It was found that the PAO system for the degradation of sulfadiazine (SDZ) exhibited 12.1-fold and 1.9-fold higher activity compared to the photocatalytic system and the anodic oxidation system alone, respectively, indicating the optoelectronic synergistic interactions over C3N4-Ti3+/TiO2-NTA. Quenching experiments and electron spin resonance results suggested that main reactive species during the degradation of SDZ by the PAO system were hydroxyl radical and superoxide radical. Additionally, three possible degradation pathways of SDZ by the PAO were proposed based on the identification of intermediate byproducts and theoretical calculation. Furthermore, the biosafety evaluation revealed a significant reduction in the biological toxicity of intermediate byproducts of SDZ. These findings provide new insights into the design and manufacturing of novel anode material for efficient degradation of recalcitrant pollutants in practical applications under solar irradiation.

Fast Ionic Actuators with Silver–Silver Chloride Electrodes and a Mixed Ionic Liquid Electrolyte

Excellent conductivity makes silver (Ag) an attractive electrode and current collector material for a variety of devices, also promising faster soft actuators. However, high reactivity challenges the use of Ag in electrochemical systems, as dendritic growth can create undesired conduction pathways and short‐circuit the oppositely polarized electrodes. The challenge of rapid Ag electrochemical migration is addressed using a mixed mixed‐room temperature ionic liquid (RTIL) system (l‐ethyl‐3‐methylimidazolium bis‐(trifluoromethylsulfonyl)‐imide and trihexyl(tetradecyl)phosphonium chloride) that prevents short‐circuiting by engaging the produced Ag+ ions with Cl− anions. The stability of the system is demonstrated on an ionic actuator using Ag–silver chloride (AgCl) electrodes and a mixed‐RTIL electrolyte. The work demonstrates fast (in 5 s) transfer of a large (0.2 C cm−2) charge to high‐specific‐surface‐area carbon without observable dendritic growth in cycling and good electromechanical performance: 4° s−1 deflection rate at 0.8 V s−1 scan rate. Simple spray‐deposition of the Ag–AgCl electrodes promises scalable and cost‐effective fabrication. The combination of high stability and vast charge capacity encourages the engagement of Ag‐based electrodes for many electrochemical applications involving organic electrolytes also beyond robotics.

Effect of Conductive Coating on Silver/Silver Chloride Electrodes for Cathodic Protection Application

Measurement of pipe to soil potential in a cathodic protection system is something that must be done which aims to monitor the performance of the installed cathodic protection system. The main measuring tool in measuring pipe to soil potential is the reference electrode. The stability of the reference electrode is important as a validation of the measurement results. So far, the stability of the reference electrode is very difficult to maintain due to frequent changes caused by the environment, especially for permanent reference electrodes that are buried in the underground or installed in seawater. Permanent reference electrode sensors commonly used in seawater is the Ag/AgCl reference electrode, but in fact the Ag/AgCl reference electrode is generally unstable and must be stabilized with a KCl solution and other problems have not been produced in Indonesia. This research will be carried out by adding a conductive layer to the Ag/AgCl electrode so that its stability can be increased. The sensor manufacturing process starts from pretreatment, electrolysis and product characterization. The results of the best coating thickness and weight gain experiments showed by the highest voltage variations and time variations (4000mV and 60 minutes). The presence of conductive solid material increases corrosion resistance from 0.00391 mm/year to 0.19549 mm/year and increases the stability of the Ag/AgCl layer ± 5 mV.

High resolution electrochemical monitoring of small pH changes

Usually pH measurements are carried out using potentiometric technique. However, sensitivity of this method is low due to limitation set by Nernst equation – the moderate resolution is a significant problem in today demand for tracking small pH changes in various application areas.We propose a novel approach that allows electrochemical monitoring of pH changes with resolution reaching below 0.01 units in alkaline, acidic or close to neutral media. The proposed method uses all-solid state pH sensitive electrode with syringaldazine (Syr) modified multi-walled carbon nanotubes as the reference electrode modulating amperometric signal of Ag|AgCl electrode used as the working one. Due to high slope of the current vs. potential dependence for low-polarizable silver / silver chloride electrode relatively small changes of reference (pH-sensitive) electrode potential are transformed to pronounced changes of the recorded current. Ultimately, this results in significant increase in resolution of traced pH changes. Moreover, the current recorded is found to be linearly dependent on changes of H+ or OH− ions concentration in a broad pH range, which additionally contributes to increased resolution readout. Advantages of herein proposed approach were fully verified by monitoring minute changes of solution pH resulting from dissolution of carbon dioxide.

Combined sustainable production technology of calcium chloride and lignin-derived porous carbon electrode materials

Sustainable co-production of materials and chemicals is essential to green production and reduction of contaminations. This work presents a sustainable production process for the co-production of porous carbon and calcium chloride using renewable lignin as the carbon precursor. The utilization of CaO as a hard template agent facilitates the creation of porous carbons through the homogeneous mixing of lignin precursors and CaO. Theoretically, it is possible to obtain carbon dioxide with high purity from the subsequent acid etching process. CaCl2 with high purity as a value-added product can be obtained by a straightforward crystallization process with a calcium collection efficiency of >93%. In this work, the formation mechanism of the pore structure evolution of LPC was elucidated by exploring the structural evolution of CaO during the reaction process. The obtained LPC has a hierarchical porous structure and specific surface areas around 700 m2 g−1. The obtained porous carbons showed excellent electrochemical performances as the cathodes of zinc ion hybrid capacitors. This combined sustainable production process could be developed as a practical process for the production of calcium chloride and porous carbons.

Electrode-Skin Impedance Model Parameter Estimation in the Frequency-Domain.

This paper presents a method for identifying parameter values for a double parallel resistor/constant-phase-element model of the electrode-skin interface for individual silver and silver/silver chloride electrodes. The impedance of each electrode was measured in five from 1 Hz-10 kHz. Phase features of these data were used to guide initial estimates for parameter values which were refined using a least squares algorithm. Resultant model impedances were compared with experimental data across a typical biosignal bandwidth (1 Hz-500 Hz). The method was effective in estimating component values in most datasets, and resulted in a mean relative RMS error of 7 % (σ = 8.3%) across the biosignal bandwidth.Clinical relevance- This work establishes a feature-based method for finding component parameter estimates for an electrode contact impedance model.

Frequency of galvanic pair detection of metal structures in the mouth in the absence of galvanic syndrome and pathological changes in the oral mucosa

BACKGROUND: Currently, numerous metal structures are used in dentistry, such as implants, pins, dentures, etc. These structures are often made of various metals and metal alloys with different electrochemical potentials. This circumstance can lead to the appearance of a galvanic cell, consisting of metal structures. In the existing literature, no data reveal the frequency of the detection of galvanic pairs of metal structures in the mouth in the absence of galvanic syndrome and oral mucosal diseases.&#x0D; AIM: To examine the detection frequency of galvanic pairs of metal structures in the mouth in the absence of galvanic syndrome and pathological changes in the oral mucosa.&#x0D; MATERIALS AND METHODS: A survey of 133 patients aged 3387 years was conducted to detect the presence of galvanic pairs of metal structures in the mouth. All patients do not have galvanic syndrome and pathological changes in the oral mucosa. The patients were divided into four age groups: 3344 years old (n = 33), 4559 years old (n = 35), 6074 years old (n = 35), and 7587 years old (n = 30). Electrochemical potentials of metal structures in the mouth were determined according to the method developed at the Department of Therapeutic Dentistry of the E. V. Borovsky Institute of Dentistry of the First Moscow State Medical University named after I.M. Sechenov (Sechenov University). An electrode made of 999 gold was used as an active indicator electrode, which was used to touch metal structures in the mouth during the study. An EHP-1 silver chloride electrode was used as a passive reference electrode. A Fluke 115 multimeter was used as a measuring device.&#x0D; RESULTS: In the group aged 3344 years, galvanic pairs were found in 18%, and they had 5.2 2.1 metal structures. The group aged 4559 years had 7.4 3.5 metal structures in the mouth, and 23% of the participants had galvanic vapors in the oral cavity. In the group aged 6074 years, 26% had galvanic vapors in the oral cavity. In this group, the maximum number of metal structures in the mouth was 7.9 4.1. In the group aged 7587 years, 20% had galvanic pairs of metal structures in the mouth, and they had 5.9 1.8 metal structures in the oral cavity.&#x0D; CONCLUSION: Galvanic pairs of metal structures in the oral cavity were found is 1826% of the participants in different age groups. The share is associated not so much with age but to a greater extent with the number of metal structures in the oral cavity. With the increased number of metal structures, the probability of the appearance of a galvanic pair in the mouth, formed by metal structures with different electrochemical potentials, increases.

Dual-ion electrochemical deionization system based on binder-free Bi2O3@MXene-Bi@MXene electrodes

Dual-ion electrochemical deionization (DEDI) system is a promising strategy for increasing the performance of capacitive deionization (CDI). We presented a simple strategy to simultaneously prepare chloride and sodium ion storage film electrode by combing MXene with Bi2O3. The sandwich-like three-dimensional (3D) structure Bi2O3@MXene film electrode can well storage sodium ions by intercalation reaction. Interestingly, the Bi@MXene film electrode can be prepared from Bi2O3@MXene film simply by reducing Bi2O3 to Bi, which can capture chloride ions by the electrochemical reaction of Bi and BiOCl. The MXene provides outstanding conductivity and flexibility for the composite film electrodes, and the introducing of Bi2O3 limits the re-stacking of MXene nanosheets while the Bi enhances the chloride ions adsorption of MXene by conversion reaction. When assembled as a DEDI device, it obtained a high desalination capacity of 86.8 mg/g at the current of 20 mA/g, and the fastest desalination rate of 3.21 mg/g/min under the current of 200 mA/g. Moreover, a strong power source built by two DEDI devices in series can drive an LED more than 5 min during the regeneration process. Such a simple and effective strategy can promote the development of binder-free electrode DEDI system.