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In this study, polyvinyl alcohol (PVA)/Na-Bentonite composites were prepared. In the preparation of composites, a maximum of 13% polymer by mass was loaded into the clay. Structural properties of composites prepared by solution mixing technique were examined using X-ray fluorescence spectrometry (XRF), Fourier Transform infrared spectrometry (FTIR) and X-ray diffraction (XRD) techniques. Dielectric properties were determined with the help of Dielectric spectroscopy (DS). From the XRF study, it was understood that the origin of the clay was Calcium bentonite (Ca-Bentonite) provided from the Asbro-Horio reservoir on the island of Milos, Greece, and that the Supplier (Imerys-Türkiye) converted the clay into NaBentonite through the sodium enrichment process. From XRD and FTIR measurements, it was observed that PVA interacted with the Na-Bentonite surface instead of being located between the Na-Bentonite galleries. This interaction between polymer and clay limited both the segmental movement of the polymer chains and the orientation of the hydroxyl groups on the clay surface. The electrode polarization effect is significantly reduced in composites with low PVA content. In low-dimensional capacitive systems, the use of materials with low dielectric constant comes to the fore to prevent resistance-capacitance (RC delay) delay. The important factor affecting the dielectric constant in the low frequency region is the electrode polarization effect. Thus, the low electrode polarization effect composites produced in this study can serve this purpose [ABSTRACT FROM AUTHOR]

The frequency‐domain dielectric spectroscopy (FDS) of humid insulating paper has been measured at different temperatures. The data show three independent dielectric processes: electrode polarization, hopping conductivity and interfacial polarization. The dielectric properties of humid insulating paper are composed of hopping conductivity and interfacial polarization, and its equivalent dielectric model can be represented by a Havriliak‐Negami (HN) relaxation branch parallel hopping conductivity. At high temperatures and low frequencies, the measured dielectric spectroscopy bends downward, which is caused by the electrode polarization. In this case, the equivalent dielectric model is composed of the body impedance of insulating paper and the electrode polarization in series. According to the equivalent dielectric model, the components of electrode polarization, hopping conductivity, and interface polarization can be separated, thereby eliminating the parasitic effect of electrode polarization on the dielectric properties of insulating paper. Both of hopping conductivity and interface polarization of insulating paper move toward high‐frequency direction with temperature increasing. For humid insulating paper with a moisture content of 5.9%, the activation energies of hopping conductivity and interface polarization are 1.18 and 0.99 eV, respectively. This difference in activation energies results in the inability of the spectrums of insulating paper to overlap with each other at different temperatures. Based on the insulating paper without oil immersion, the results obtained in this article are not affected by oil or oil‐immersion operations. This provides a reference for exploring the dielectric properties and physical mechanisms of oil‐paper composite insulation materials widely used in high‐voltage equipment. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Soft robotics systems are currently under development using ionic electroactive polymers (i‐EAP) as soft actuators for the human‐machine interface. However, this endeavor has been impeded by the dilemma of reconciling the competing demands of force and strain in i‐EAP actuators. Here, the authors present a novel design called "ions‐silica percolated ionic dielectric elastomer (i‐SPIDER)", which exhibits ionic liquid‐confined silica microstructures that effectively resolve the chronic issue of conventional i‐EAP actuators. The i‐SPIDER actuator demonstrates remarkable electromechanical conversion capacity at low voltage, thanks to improved ion accumulation facilitated by interpreting electrode polarization at the electrolyte‐electrode interface. This approach concurrently enhances both strain (by approximately 1.52%) and force (by roughly 1.06 mN) even at low Young's modulus (merely 5.9 MPa). Additionally, by demonstrating arachnid‐inspired soft robots endowed with user‐desired tasks through control of various form factors, the development of soft robots using the i‐SPIDER that can concomitantly enhance strain and force holds promise as a compelling avenue for ushering in the next generation of miniaturized, low‐powered soft robotics. [ABSTRACT FROM AUTHOR]

In electrochemically active systems, such as fuel cells, electrolyzers, and batteries, researchers often modify the material chemistry or operating variables at one of the electrodes (e.g., the cathode) to investigate its properties. This approach assumes that changes in measured polarization and cell performance result solely from the modifications made to the selected electrode, while the conditions at the other electrode (e.g., the anode) remain constant. However, the potential interactions between the polarizations of these two electrodes have remained unclear. In our study, we utilize a voltage probe capable of precisely determining electrode polarization. Our findings reveal three key insights: 1. The quantification of electrode polarization becomes feasible through the implementation of a voltage probe. 2. The fuel electrode plays a pivotal role in the performance of state-of-the-art solid oxide cells, with its influence being comparable to that of the oxygen electrode. 3. A reciprocal interaction exists between the two electrodes within a solid oxide cell. Consequently, when there are changes in the chemistry or operational conditions at one electrode, the polarization of the other electrode changes simultaneously.

The feasibility of electrolytic conductivity is performed using two-electrode system. A precision LCR meter is utilized to measure the ac resistance of electrolytic solution which is traceable to reference standard of impedance at CSIR-National Physical Laboratory. KCl solutions with different molality are used to establish the measurement system. The measurement of ac resistance is performed at frequencies above 10 kHz to minimize the impact of electrode polarization. Initially, the measurement setup was validated using a certified reference material. The KCl solutions with different molality are prepared gravimetrically. Thereafter, electrolytic conductivity of the aqueous solutions is computed for different molality of KCl solutions. The preliminary measurement suggested that the two-electrode system may be utilized for the measurement of electrolytic conductivity from 0.005 to 0.1 M upto 1 MHz. [ABSTRACT FROM AUTHOR]

An improvement in ion transport behavior and dielectric properties of polyethylene oxide based polymer electrolytes have been investigated upon the dispersal of TiO2 nanoparticles. TiO2 nanoparticle is synthesized with the help of well‐known sol–gel technique. The different compositions of polymer electrolyte systems are prepared by the solution cast technique. Nanocomposite polymer electrolytes (NCPEs) films are synthesized by loading of nanoTiO2 particle in a pristine polymer electrolyte matrix. The structural and morphological behaviors of nanocomposite polymer electrolytes (NCPEs) have been subsequently characterized by XRD and SEM studies. The ionic behavior of synthesized NCPEs is ascertained by Wagner's polarization technique. AC and DC conductivity of polymer electrolyte films have been carried out using impedance spectroscopic techniques. Dielectric relaxation studies of polymer electrolytes are examined using impedance spectroscopic data. The conductivity relaxation mechanism of NCPEs has been concluded with the help of modulus formalism. DC conductivity of best ion‐conducting NCPEs at room temperature has been found to σ = 2.5 × 10−5 S cm−1. The electrode polarization effect has completely vanished in the dielectric and modulus formalism and the conductivity scaling data show a single master curve observed in ion dynamics. The change in ionic conductivity with frequency and temperature is studied by impedance spectroscopic investigations. The effect of salt on dielectric parameters of NCPEs is also extracted from impedance spectroscopic data to explore underlying ion dynamics. [ABSTRACT FROM AUTHOR]

The complex dielectric permittivity of hydroxypropyl methyl cellulose (HPMC)-water mixture was measured by using Time Domain Reflectometry (TDR) and Frequency Domain (LCR) Technique at 25 oC. The complex dielectric permittivity ε*(ω), complex electrical modulus M*(ω), complex electrical conductivity σ*(ω), loss tangent (tanδ), static dielectric constant (ε0) and relaxation time (τ) have been determined for the cellulose-water system. [ABSTRACT FROM AUTHOR]

Dielectric polarization and electric polarization of electrodes are the common features of polar materials. We described methods to analyze their contributions and showed that both dependencies on temperature of dielectric conductivity and electrode polarization and the exponents characterizing these dependencies are excellent markers of phase transitions. Proposed methods were applied to several compounds, such as liquid crystals, pharmacological compounds, monoalcohols, polyalcohols, and various thermodynamic phases. Common behavior was noted for materials under study. In similar phases, various substances have the same values of the exponents characterizing electric conductivity and contribution from the electrode polarization. These exponents show discontinuities at phase transition temperatures between crystal-like and liquid-like phases. [ABSTRACT FROM AUTHOR]

With the rapid development of electric vehicles, people have higher requirement for the energy density and lifespan of power batteries. The cycle performance and rate performance of lithium-ion batteries can be effectively improved through the modification of the positive and negative active materials, the application of new conductive agents and binders, and the optimized design of the electrode group distribution ratio. However, the problems caused by the preparation process of the traditional electrode and the characteristics of the single-layer electrode structure put a limit on the further improvement of the performance of the lithium-ion battery. Therefore, solving the problems of the traditional single-layer electrode structure itself is an important direction of lithium-ion battery research. Three solutions to solve the problems of the single-layer electrode structure by analyzing the related research on the multilayer composite electrode structure were summarized in this paper which are increasing the stability of the electrode surface, increasing the conductivity of the electrode surface and adjusting the internal component distribution of the electrode, and they have their own advantages.By analyzing the characteristics and limitations of different schemes and preparation processes, new directions and ideas for electrode design and engineering application of lithium-ion batteries and other battery systems were proposed in this paper. Finally, the current research status of the multilayer composite electrode structure was summarized in this paper.

[Display omitted] • Extracting correct results from the electrical measurements are very important. • Extreme low and high frequency dielectric data are affected by parasitic elements. • Electrode polarisation capacitance and dc conductance cause huge problem in low frequency region. • An impedance model has been utilised to eliminate the effect of electrode polarisation capacitance and dc conductance. • With the elimination of parasitic effects, it becomes possible to extract true values of permittivity and loss. Dielectric materials are supposed to possess very high resistance (infinite in an ideal case) so that there is no direct current loss in the capacitors using these materials. However, despite best efforts, dielectric materials possess some ionic impurities. When an electrical signal is applied on these materials through electrodes, these ions move to electrodes and mask them. This phenomenon is called electrodes polarization. Electrode polarization phenomenon prohibit to determine correct values of the dielectric parameters of such materials particularly in the low frequency region (below ∼ 10–100 kHz). Here, a model has been used to successfully remove electrode polarization effect from the dielectric data and thereby resulting measurement of true characteristic parameters of the materials. Success of the model has been demonstrated by exhibiting appropriate examples of the permittivity and loss data on the materials exhibiting wide variety of molecular relaxations mechanisms. [ABSTRACT FROM AUTHOR]

Dielectric polarization and electric polarization of electrodes are the common features of polar materials. We described methods to analyze their contributions and showed that both dependencies on temperature of dielectric conductivity and electrode polarization and the exponents characterizing these dependencies are excellent markers of phase transitions. Proposed methods were applied to several compounds, such as liquid crystals, pharmacological compounds, monoalcohols, polyalcohols, and various thermodynamic phases. Common behavior was noted for materials under study. In similar phases, various substances have the same values of the exponents characterizing electric conductivity and contribution from the electrode polarization. These exponents show discontinuities at phase transition temperatures between crystal-like and liquid-like phases.

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In this work, we intended to investigate the antimicrobial activity, biocompatibility, and study the electrical conductivity of the polypyrrole on the surface of the conducting hydrogel such as carboxymethyl cellulose-g-poly (acrylamide-co-acrylamido-2-methyl-1-propane sulfonic acid). Broadband dielectric spectroscopy was employed to follow up the electrochemical double layer that developed at the electrode surfaces. Biocompatible conducting hydrogel showed the establishment of the electrical double layer in a wide range of frequencies, and the DC-conductivity values were in top of the semiconductors range. The addition of polypyrrole not only diminishes the effect of water transformations on conductivity, but also manifests the permittivity's value (from 1.7 × 106 to 2.4 × 108). In addition, it lowers the charging–discharging loss of energy. Comparing the prepared conductive hydrogels to the ionic liquids, it showed that hydrogels have more ability to be applicable in the energy storage systems. Also, the prepared hydrogels biocompatibility was tested against normal cell line (Vero cells) which recorded the excellent compatibility with cells. The antimicrobial activity was examined against some pathogens; (i) Gram-negative bacteria: Escherichia coli (NCTC-10416) and Pseudomonas aeruginosa (NCID-9016); (ii) Gram-positive bacteria: Bacillus subtilis (NCID-3610); (iii) unicellular fungi: Candida albicans (NCCLS-11) and (iv) filamentous fungi Aspergillus niger (ATCC-22342). [ABSTRACT FROM AUTHOR]

This paper yields an overview on the evolution of the concept of polarization applied to electrochemical systems, ranging from electrodes to cells. The historical discussion starts at the early phase of the development of electrochemistry when current-controlled measurements were possible only, and when the early definitions of polarization, depolarization and depolarizer were created. A number of contemporary handbooks, recommendations and other reference resources are listed in which these concepts are represented in various ways, from conservative definitions to attempts of redefining them. The traditional definitions are confronted with the everyday use of professional language, drawing attention to the fact that the widespread application of potential-controlled electrochemical measurements led to new meanings. Some suggestions are made that open room for the application of the term of polarization in accord with the modern methodologies, without compromising the traditional introduction of the term. Polarization-related phenomena in biological membranes are not dealt with in the present work. [ABSTRACT FROM AUTHOR]

A precision LCR meter along with a liquid dielectric cell have been used to measure the capacitance and resistance of the binary mixtures of methyl ethers with water at 298.15 K in the frequency range of 20 Hz to 2 MHz. The measured values are used to compute the complex dielectric permittivity ε*(ω). The parameters like complex electrical modulus M*(ω), complex electrical conductivity σ*(ω) and loss tangent (tan δ)are obtained from the complex dielectric permittivity values of the samples. The values of excess dielectric permittivity of the samples are calculated using the respective static dielectric permittivity values. The refractive indices of all the samples were measured using Abbe's refractometer at 298.15 K. All these parameters are used to gain insight into the concentration dependent variation in dielectric and electrical properties of the binary mixtures. A dominance of electrode polarization effect in the lower frequency region is observed for all the samples studied here. [ABSTRACT FROM AUTHOR]

Although microbial fuel cells (MFCs) are a very clean electricity-producing bioelectrochemical technology, their large internal resistance limits their power generation capacity. To reduce the MFC internal resistance, according to the principle of favorable electric field, a microbial electrolysis cells (MECs) was coupled with MFC to form two kinds of MFC-MEC coupling systems: a shared anode MFC-MEC system (SA-MFC) and a shared cathode MFC-MEC system (SC-MFC). Compared with those of the uncoupled MFC, the total internal resistances (R tol) of the SA-MFC and the SC-MFC were 2119.04 Ω and 2416.44 Ω, respectively, lower than that of the uncoupled MFC (3392.05 Ω). The average working voltages of the SA-MFC and the SC-MFC reached 121.40 mV and 100.43 mV, respectively, which were 41.71% and 17.23% higher than that of the uncoupled MFC (85.67 mV), and the maximum power output reached 121.03 mW and 94.09 mW, respectively, which were 1.93 times and 1.50 times that of the uncoupled MFC (62.58 mW), indicating that the SA-MFC had optimal power production performance. The reasons for these differences were that the external electric field provided by the MEC created an additional driving force for the electrode reaction, extracellular electron transfer and liquid phase mass transfer, resulting in weakened electrode polarization. This research provides a new way to reduce the internal resistance of MFCs and increase their power output. [Display omitted] • Constructing a microbial fuel cell coupling microbial electrolytic cell system. • Shared anode coupling system achieves optimal power production performance. • Calculate the contribution rate of the internal resistance to the power output. • Electric field can improve electrochemical performance of microbial fuel cell. [ABSTRACT FROM AUTHOR]

Dielectric spectroscopy (DS) is a promising cell screening method that can be used for diagnostic and drug discovery purposes. The primary challenge of using DS in physiological buffers is the electrode polarization (EP) that overwhelms the impedance signal within a large frequency range. These effects further amplify with the miniaturization of the measurement electrodes. In this study, we present a microfluidic system and the associated equivalent circuit models for real-time measurements of cell membrane capacitance and cytoplasm resistance in physiological buffers with 10 s increments. The current device captures several hundreds of biological cells in individual microwells through gravitational settling and measures the system’s impedance using microelectrodes covered with dendritic gold nanostructures. Using PC-3 cells (a highly metastatic prostate cancer cell line) suspended in cell growth media (CGM), we demonstrate stable measurements of cell membrane capacitance and cytoplasm resistance in the device for over 15 min. We also describe a consistent application of the equivalent circuit model, starting from the reference measurements used to determine the system parameters. The circuit model is tested using devices with varying dimensions, and the obtained cell parameters between different devices are nearly identical. Further analyses of the impedance data have shown that accurate cell membrane capacitance and cytoplasm resistance can be extracted using a limited number of measurements in the 5 MHz to 10 MHz range. This will potentially reduce the timescale required for real-time DS measurements below 1 s. Overall, the new microfluidic device can be used for the dielectric characterization of biological cells in physiological buffers for various cell screening applications.

• The freezing point of tissue of isotonic osmolality is −0.6 ∘C. • At −5 ∘C impedance was increased by more than an order of magnitude. • We estimated that at −5 ∘C 89% of the water in the extracellular space was frozen. • Phase shifts at low temperatures reflect slower freezing in the intracellular space. Increasing impedance during freezing might be a valuable marker for guiding cardiac cryo-ablation. We provide model based insights on how decreasing temperature below the freezing point of tissue relates to the percentage of frozen water. Furthermore, we provide experimental data for comparing this percentage with the increase in impedance. Measurements were performed on a bovine tissue sample at frequencies between 5 and 80 kHz. Slow cooling and heating rates were applied to minimize temperature gradients in the myocardial sample and to allow accurate assessment of the freezing point. Computer simulation was applied to link impedance with temperature dependent conductivities. The osmotic virial equation was used to estimate the percentage of frozen water. Measurements identified the freezing point at −0.6 ∘C. At −5 ∘C, impedance rose by more than a factor of ten compared to that at the freezing point and the percentage of frozen water was estimated as being 89%. At −49 ∘C impedance had increased by up to three orders of magnitude and ice formation was most pronounced in the extracellular space. Progressive ice formation in tissue is reflected by a large increase in impedance, and impedance increases monotonically with the percentage of frozen water. Its analysis allows for experimental assessment of factors relevant to cell death. Solid ice contributes to the rupture of the micro-vasculature, while phase shifts reflect concentration differences between extra- and intracellular space driving osmotic water transfer across cell membranes. [ABSTRACT FROM AUTHOR]

Computational models including electrode polarization can be essential to study electrode/electrolyte interfacial phenomena more realistically. We present here a constant‐potential classical molecular dynamics simulation method based on the extended Lagrangian formulation where the fluctuating electrode atomic charges are treated as independent dynamical variables. The method is applied to a graphite/ionic liquid system for the validation and the interfacial kinetics study. While the correct adiabatic dynamics is achieved with a sufficiently small fictitious mass of charge, static properties have been shown to be almost insensitive to the fictitious mass. As for the kinetics study, electrical double layer (EDL) relaxation and ion desorption from the electrode surface are considered. We found that the polarization slows EDL relaxation greatly whereas it has little impact on the ion desorption kinetics. The findings suggest that the polarization is essential to estimate the kinetics in nonequilibrium processes, not in equilibrium. © 2019 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

4-electrode setups are usually used to measure the dielectric response (complex conductivity) of sandstones, as it is known that 2-electrode systems are sensitive to unwanted electrode polarization at low frequency. Moreover, electrode polarization (EP) occurs in the frequency range where the characteristic relaxation associated to the grain size also occurs, which can therefore theoretically be assessed using 4-electrode setups. Nonetheless, we find that other parameters of interest (porosity, salinity) can easily be extracted from the frequency range ~ 1–10 kHz, beyond the one affected by EP using a 2-electrode setup. An additional unwanted effect (“pseudo-inductance”) is observed in the frequency range 10 kHz–1 MHz during our experiments. Even though the origin of this effect remains unknown, it is shown to be correlated with the ionic strength of the system and the electrode separation. The bulk polarization region, i.e., the region of intermediate frequencies devoid of EP and pseudo-inductance polarizations, is the one of interest, as the complex conductivity of the system is there only dependent on material parameters such as the porosity of the sandstone and the conductivity of the electrolyte. We demonstrate that in the bulk region the model predicts the complex conductivity response, when these porosity and ionic strength are known. The model has been validated using laboratory measurements on a Bentheim sandstone saturated with five different NaCl concentrations: 5, 10, 100, 170, and 540 mM.

Abstract Complex dielectric function ε⁎(ω) = ε′(ω) − ε″(ω) of the binary mixtures of amino silicone oil and methyl ethyl ketone were measured using precision LCR meter in the frequency range 100 Hz to 2 MHz at 298.15 K temperature. Complex dielectric function data are represented in different formalisms like complex a.c. conductivity σ⁎(ω), complex modulus M⁎(ω) and complex impedance Z⁎(ω). The refractive index of the same system was determined at 298.15 K temperature using Abbe's refractometer. These presentations are used to find out different parameters such as electrode polarization relaxation time (τ EP), relaxation time (τ EP ′), ionic conduction relaxation time (τ σ), dc conductivity (σ dc) and static permittivity (ε 0) of the liquid samples. Determined parameters are used to gain information about the effect of concentration variation on dielectric and electrical properties of the mixtures. Complex impedance Z⁎(ω) data were fitted to an equivalent circuit, having four elements including capacitance (C 2) representing electrode double layer capacitance. The geometric relaxation time was calculated using product of resistor (R 2) and capacitor (C 1) of the equivalent circuit. Lower frequency dielectric data is dominated by the EP effect. The systematic change is observed in all the parameters with change in concentration of amino silicone oil in methyl ethyl ketone. Viscosity dependence of dc conductivity of the system is also investigated. Graphical abstract Unlabelled Image Highlights • Complex permittivity data of ASO-MEK mixtures fit well to Coelho model. • Relaxation dynamics of all mixtures are in between the parent compounds. • Dielectric, electrical properties of mixture show strong concentration dependence. • dc conductivity and viscosity show inverse proportionality relationship. • Dynamical process of EDL phenomenon is independent of mixture concentration. [ABSTRACT FROM AUTHOR]

The microwave effect on barium strontium ferrate (BSF) was determined, and core-shell BSF-xCe cathode was co-fired with ceria-based electrolyte in a focused microwave cavity. The solubility of cerium (Ce) in BSF was up to x = 10 mol%. The grain size of the microwave-sintered BSF was smaller. The conductivity of BSF-20Ce cathode with the lower transition temperature was significantly higher than that obtained by conventional sintering. The ohmic (R ohm ) and electrode polarization (R p ) resistances of the fuel cells were significantly reduced. The open-circuit voltage and peak power density of the microwave co-fired fuel cells increased with the Ce coatings. The high ionic conductivity at high operation temperature was due to the generation of more oxygen vacancies without clustering, caused by the effective absorption of microwave by the low valence iron oxide. Thus, the enhanced diffusion of Ce and the reduced R p and R ohm by the microwave energy improved the performance of fuel cells. [ABSTRACT FROM AUTHOR]

The current work reports the concurrent passivation of interstitial and oxygen vacancy mediated defect states in low temperature processed ZnO electron transport layer (ETL) via Ultraviolet-Ozone (UVO) treatment for fabricating highly efficient (maximum efficiency: 16.70%), triple cation based MA 0.57 FA 0.38 Rb 0.05 PbI 3 (MA: methyl ammonium, FA: formamidinium, Rb: rubidium) perovskite solar cell (PSC). Under UV exposure, ozone decomposes to free atomic oxygen and intercalates into the interstitial and oxygen vacancy induced defect sites in the ZnO lattice matrix, which contributes to suppressed trap-assisted recombination phenomena in perovskite device. UVO treatment also reduces the content of functional hydroxyl group on ZnO surface, that increases the inter-particle connectivity and grain size of perovskite film on UVO treated ZnO ETL. Owing to this, the perovskite film atop UVO treated ZnO film exhibits reduced micro-strain and dislocation density values, which contribute to the enhanced photovoltaic performance of PSC with modified ZnO ETL. The modified PSCs exhibit higher recombination resistance (R Rec ) ∼40% compared to pristine ZnO ETL based control devices. Adding to the merit, the UVO treated ZnO PSC also demonstrates superior device stability, retaining about 88% of its initial PCE in the course of a month-long, systematic degradation study. [ABSTRACT FROM AUTHOR]

The accuracy of data obtained with the Direct Current (DC) electrical method is reduced by the electrode polarization effect, which is caused by current stimulation when the electrodes of the multi-electrode acquisition system are alternately used as the current and the potential electrodes. With the purpose of studying the characteristics of electrode polarization, the continuous potential responses of the electrodes in a conventional multi-electrode acquisition system (single-mode multi-electrode acquisition system) and the proposed double-mode multi-electrode acquisition system were adopted before and after current stimulation, by varying the electrode material, voltage amplitude and current duration. The results showed that for the single-mode acquisition system the electrode polarization was stronger and the electrodes possessed a stronger chemical activity, a longer current duration and a higher voltage amplitude that increased rapidly and then decayed after current stimulation. The average time for the potential to be restored to the background level was greater than 1.5 h, and the electrode polarization of a stainless steel electrode was found to be stronger than a copper one. Thus, along with the action of current stimulation, the potential data was significantly influenced by the electrode polarization when adopting a conventional multi-electrode acquisition system. The results also demonstrated that the electrode polarization had a relatively weak influence on the resistivity data due to the data reprocessing. [ABSTRACT FROM AUTHOR]

Developing oxygen electrodes with improved polarization is a major concern for improving the commercial viability of solid oxide electrolyzers (SOECs). SrTi 0.3 Fe 0.7 O 3− δ (STF) has recently emerged as a catalytically active and highly stable oxygen electrode, and its performance has been shown to improve when it is deficient in Sr. However, the mechanism by which Sr deficiency alters the STF polarization behavior still remains to be clarified. In this study, we explored the electrochemical characteristics of Sr 1− x Ti 0.3 Fe 0.7 O 3− δ (STF x ; x = 0.03 and 0.06) to elucidate the effect of Sr deficiency on electrode polarization. The results showed that Sr deficiency effectively improves the electrode/electrolyte interfacial resistance and oxygen-transport kinetics. However, the latter effect was observed to be rather diminished by the degraded microstructure, possibly owing to enhanced sinterability of the Sr-deficient compositions. Symmetric cell life tests conducted over ∼1110 h revealed that STF x maintains low polarization to prevent electrode delamination. The Ni–YSZ supported cell with the STF0.06 electrode exhibits improved steam electrolysis performance, yielding a high current density of ∼2.71 A cm–2 at 750 °C and 1.3 V. • Electrochemical evaluation of Sr-deficient SrTi 0.3 Fe 0.7 O 3−δ oxygen electrodes. • Sr deficiency improves electrode/electrolyte interfacial contact and O 2 transport. • Reduced porosity and surface area are observed for Sr-deficient compositions. • Sr-deficient SrTi 0.3 Fe 0.7 O 3−δ exhibits improved steam electrolysis performance. [ABSTRACT FROM AUTHOR]

Inappropriate handling of copper (Cu) and lead (Pb)-containing wastewater resulting from metallurgical and smelting industries in Northwest China encourages their migration to surrounding environments. Their accumulation causes damage to liver and kidney function. The electrokinetic (EK) technology is considered to be an alternative to traditional remediation technologies because of its great maneuverability. The EK remediation is accompanied by the electrode polarization and the focusing effect toward affecting removal efficiency. In this study, a nanocomposite hydrogel (NCH) electrode was proposed and applied to the EK remediation of Cu- and Pb-contaminated loess. The mechanical, adsorption capacity, adsorption kinetics, and electrochemical properties of the NCH electrode were investigated in detail, followed by microscopic analyses of Scanning Electron Microscope (SEM), Energy Dispersive X-ray Spectroscopy (EDS), and Raman spectrometer. Results showed that the enhancement of the mechanical properties of the NCH electrode was attributed to the crosslinks of graphene nanoparticles, calcium alginate, and hydrogen bonds, while the Cu or Pb adsorption by the NCH electrode was in a chemisorption manner. The second layer formation might address the increase in adsorption capacity with increasing temperature. These results highlight the relative merits of the NCH electrode and verify the potential of applying the NCH electrode to the EK remediation of Cu- and Pb-contamianted loess. [Display omitted] • Hydrogen bonds promoted the crosslinked structure formation. • The surface functional groups reduced the mobility of copper and lead ions. • The non-faradaic nature of the proposed NCH electrode reduced the polarization. • The proposed NCH electrode outperformed traditional electrodes. [ABSTRACT FROM AUTHOR]

• A disposable in-line cell density sensor using low-cost materials is developed. • A distance-preserving loss function between conversions is used in data fitting. • A physics-inspired method is developed to leverage α-relaxation for sensing. • The gray-box model has shown good performance in predicting new data. • α-relaxation reflects cell density accurately by a power-law relation. This paper presents the development of low-cost, disposable impedance-based sensors for real-time, in-line monitoring of suspension cell culture. The sensors consist of electrical discharge machining (EDM) cut aluminum electrodes and polydimethylsiloxane (PDMS) spacers, both of which are low-cost materials that can be safely disposed of. Our research demonstrates the capability of these low-cost sensors for in-line, non-invasive monitoring of suspension cell growth in cell manufacturing. We use a hybrid equivalent circuit model to extract key features/parameters from intertwined impedance signals, which are then fed to a novel physics-inspired (gray-box) model designed for α-relaxation. This model determines viable cell count (VCC), a critical quality attribute (CQA) in cell manufacturing. Predicted VCC trends are then compared with image-based cell count data to verify their accuracy. [ABSTRACT FROM AUTHOR]

The presented work demonstrates the development of highly stable low temperature processed Cesium compound incorporated ZnO electron transport layer (ETL) for perovskite solar cells (PSCs). Cesium compounds such as CA (cesium acetate) and CC (cesium carbonate) modified ETLs are employed for fabricating highly efficient (PCE: ~ 16.5%) mixed organic cation based MA 0.6 FA 0.4 PbI 3 PSCs via restricted volume solvent annealing (RVSA) method. Here, CA ETL demonstrates a 50 meV upshift in Fermi level position with respect to CC ETL, contributing to higher n-type conductivity and lower electron injection barrier at the interface. Furthermore, CA ETL also exhibits profound influence on the perovskite microstructure leading to larger grain size and uniform distribution. Cesium acetate incorporated devices exhibit about 82% higher PCE compared to conventional CC devices. In addition to higher photovoltaic performance, CA devices exhibit mitigated photo-current hysteresis phenomena compared to CC devices, owing to suppressed electrode polarization phenomena. Besides, the stability of the CA devices are 400% higher than the conventional CC devices, retaining almost 90% of its initial PCE even after a month-long (30 days) systematic degradation study. The mechanism behind superior performance and stability is investigated and discussed comprehensively. [ABSTRACT FROM AUTHOR]

Natural rubber (NR) isolated from Hevea Brasiliens and reinforced with different amounts of cellulose nanowhiskers (extracted from the rachis of date palm tree) was investigated using differential scanning calorimetry and dielectric spectroscopy in the frequency range 0.1 Hz to 1 MHz, and the temperature range −80 to 200 °C. The experimental dielectric data were analysed within the formalisms of dielectric permittivity, complex conductivity and complex modulus. The results were discussed in terms of dc conductivity, interfacial polarization and electrode polarization. The paper aims to investigate especially the electrode polarization observed at low frequency and/or high temperature (LF/HT). It is exhibited that the understanding of the frequency space charge relaxation behaviour trapped close to the material/electrode interface will help one to elucidate the charge dynamics in the quasi static range. So charge carrier concentration and mobility in the sample at high temperature can be evaluated through the electrode polarization modeling of broadband dielectric spectroscopy data. [ABSTRACT FROM AUTHOR]

By re-evaluating the outcome of conductivity measurements on carbonate-based composites recently reported in the literature, it is demonstrated that the disregard of fundamental relationships of electrochemistry makes the interpretation provided in the literature a pure speculation. Therefore, the supposed evidence of multi-ionic conduction and ionic conductivity enhancement must be regarded as completely unfounded. Despite the non-existence of these exceptional conduction properties, composite electrolytes comprising an alkali ion and an oxygen ion conductor may prove to be more advantageous than single-phase electrolytes due to a substantial difference in the nature of the electrode polarization during ion flow. [ABSTRACT FROM AUTHOR]

Development of a simple electrochemical immunosensor, for the direct detection of biotin, is important for monitoring biotin content. A displacement assay was used in biotin detection, in which surface-bound antibodies were dissociated from the surface of immunosensor in the presence of free biotin. Pre-treatment of samples is not required for biotin detection using this electrochemical immunosensor. Using this electrochemical immunosensor, the recoveries of biotin in the two infant formulas A and B were 93.9% and 91.3%, respectively, of their biotin concentrations as stated on their packaging. The direct detection of biotin, with this electrochemical immunosensor, in supplements X, Y, and Z, showed recoveries as high as 92.9%, 106.5%, and 100.0%, respectively. The accuracy of our electrochemical immunosensor was validated with high pressure liquid chromatography (HPLC). The surface of immunosensor had a strong anti-fouling property and high specificity for actual applications in complex matrices. Additionally, the developed immunosensor shows good stability, reproducibility, and intra- and inter-day precision. This electrochemical immunosensor can directly detect biotin in infant formulas, biotin-containing supplements, and serum. [ABSTRACT FROM AUTHOR]

We, herein, reported a giant positive dielectric tunability of ∼70% at room temperature under an applied field of 200 V/cm in nominally pure Na 1/2 Bi 1/2 Cu 3 Ti 4 O 12 ceramics. Our results reveal that both Schottky and Langevin effects have contribution to this tunability. 10% Bi-overdose switches the positive dielectric tunability to a giant negative dielectric tunability. Hopping oxygen vacancies blocked by the electrode yielding the so-called electrode polarization is believed to be responsible for the negative dielectric tunability. [ABSTRACT FROM AUTHOR]

The dielectric spectra of colloidal systems often contain a typical low frequency dispersion, which usually remains unnoticed, because of the presence of strong conduction losses. The KK relations offer a means for converting  into  data. This allows us to calculate conduction free  spectra in which the l.f. dispersion will show up undisturbed. This interconversion can be done on line with a moving frame of logarithmically spaced  data. The coefficients of the conversion frames were obtained by kernel matching and by using symbolic differential operators. Logarithmic derivatives and differences of  and  provide another option for conduction free data analysis. These difference-based functions actually derived from approximations to the distribution function, have the additional advantage of improving the resolution power of dielectric studies. A high resolution is important because of the rich relaxation structure of colloidal suspensions. The development of all-in-1 modelling facilitates the conduction free and high resolution data analysis. This mathematical tool allows the apart-together fitting of multiple data and multiple model functions. It proved also useful to go around the KK conversion altogether. This was achieved by the combined approximating  and  data with a complex rational fractional power function. The all-in-1 minimization turned out to be also highly useful for the dielectric modelling of a suspension with the complex dipolar coefficient. It guarantees a secure correction for the electrode polarization, so that the modelling with the help of the differences  and  can zoom in on the genuine colloidal relaxations.

Miniaturized electrodes are introduced in life sciences in a great number and variety. They are often designed for a special purpose without the need of quantitative analysis, such as for detecting cells or water droplets in a fluid channel. Other developments aim in monitoring a single quantity in a process where all other factors held constant.

In this study, the dielectric behavior of polyanionic electrically conductive superabsorbent hydrogel based on sodium alginate- g -poly(AM-co-ECA-co-AMPS) was investigated by broadband dielectric spectroscopy (BDS). The dielectric spectra obtained from −70 to 70 °C showed a superposition of three distinctive processes, electrode polarization, charge carrier's transport, and a molecular relaxation process. These dynamic processes were further analyzed along with the effect of both temperature and reduced graphene oxide (rGO) content. The development of a clear electrochemical double layer (ECDL) at the electrode/hydrogel interface strongly supports its possible application in supercapacitors' forms of energy storage. TGA, DSC, rheology, and electrochemical properties were studied. Furthermore, when the composite hydrogel with rGO content of 2.5 % was assembled into a symmetric supercapacitor, it displayed a specific capacitance of 756 F.g−1 at 1 A.g−1 and 704 F.g−1 after 5000 cycles with high capacitance retention of 93.2 %. The superior conductivity and porous structure of the rGO composite hydrogel are credited with the hydrogel's excellent electrochemical capabilities. [ABSTRACT FROM AUTHOR]