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This paper focuses on long‐term tests held during 1,000 h on different Membrane‐Electrode‐Interconnect Assemblies (MEIAs), consisting of an Fe‐Ni alloy interconnect and an electrochemical cell based on a Ce0.8Sm0.2O2–δ electrolyte, the double‐layer working electrode with a La2NiO4 + δ – Ce0.8Sm0.2O2–δ composite functional layer, and a LaNi0.6Fe0.4O3–δ current collector layer, and a platinum reference electrode (O2, LaNi0.6Fe0.4O3–δ|La2NiO4 + δ – Ce0.8Sm0.2O2–δ|Ce0.8Sm0.2O2–δ|Pt, O2). These tests were carried out on MEIAs with the Cr‐free 47ND alloy of the Fe–Ni system with and without surface modification at 850°C in air. The electrochemical performance of MEIAs was studied without polarization as well as under cathodic and anodic polarization with current density 0.5 A cm−2 by means of electrochemical impedance spectroscopy (EIS). The mechanism of the MEIA evolution during long‐term test is discussed. [ABSTRACT FROM AUTHOR]

Implantable medical devices require protective encapsulation to isolate them from the biological environment. Parylene‐C (PaC) is a prevalent encapsulation polymer but is susceptible to cracking, delamination, oxidation, and moisture penetration over time. This study demonstrates that 3D micro‐anchors fabricated by direct laser writing (DLW) greatly enhance PaC lifetime and encapsulation properties. The PaC film is vapor deposited onto these anchor points, followed by ultraviolet radiation (UV)‐curing‐induced shrinkage. Electrochemical impedance spectroscopy (EIS) during accelerated aging tests in reactive solutions (87 °C, 15 mM H2O2) is performed to monitor film degradation over time. Unpatterned PaC films failed before reaching the 3.25 accelerated year benchmark, while 100 µm spaced micro‐anchors extended encapsulation up to 5.5 equivalent years. Subsequent improvements are achieved with a spacing of 50 µm, demonstrating viability up to ≈6 equivalent years. This research demonstrates the benefit of engineering anchor points for preventing delamination of the PaC layer and significantly enhancing encapsulation properties. Printed 3D micro‐anchors are an extremely flexible platform, with many different shapes and sizes possible which can further enhance longevity. The success in increasing coating lifetimes offers a promising direction for improving long‐term implantable medical devices, potentially revolutionizing their longevity and reliability. [ABSTRACT FROM AUTHOR]

The corrosion resistance properties of a new type of environmentally-friendly organic inhibitor containing amino ketone molecules are presented in this paper. To evaluate the prevention effect of the inhibitor on corrosion of reinforcement, the electrochemical characteristics of steels in the simulated concrete pore solution (SPS) were investigated under varied conditions of the relevant parameters, including concentrations of the inhibitor and NaCl, pH value, and temperature. The inhibition efficiency of the material was characterized through electrochemical impedance spectroscopy (EIS), potentiodynamic polarization, and the weight loss of steels. The results reveal a significant improvement in the corrosion resistance of steels with the inhibitor. A maximum resistance value of 89.07% was achieved at an inhibitor concentration of 4%. Moreover, the new organic inhibitor exhibited good corrosion protection capability for steels under different NaCl concentrations. Its inhibition efficiency was determined to be 65.62, 80.06, and 66.30% at NaCl concentrations of 2, 3.5 and 5%, respectively. On the other hand, it was found that an alkaline environment was favorable for an enhanced corrosion prevention effect, and an optimal pH value of 11.3 was observed in this work. Besides, the inhibition efficiencies at different temperatures showed a trend of 25 > 35 > 40 > 20 > 30 °C, with a maximum value of 81.32% at 25 °C. The above results suggest that the new organic material has high potential to be used as an eco-friendly and long-term durable inhibitor for steel corrosion prevention under complex conditions. [ABSTRACT FROM AUTHOR]

Molten nitrates or nitrate–nitrite mixtures have been used as heat transfer fluid as well as thermal energy storage medium in concentrated solar power plants and other industrial applications. However, containment materials in contact with these molten salts are subjected to molten salt corrosion, which has been a concern over the years. In this investigation, the corrosion behavior of pure Ni, Fe, Cr, and Fe‐5Cr alloy (in weight percent) has been examined at 400°C in molten nitrates using electrochemical impedance spectroscopy and gravimetric tests. It is shown that Ni, Fe, and Fe‐5Cr exhibit mass gain, with the best corrosion resistance for Ni followed by Fe‐5Cr and Fe, while pure Cr goes through fast dissolution, forming hexavalent chromium product K3Na(CrO4)2. The increase of salt basicity from Solar Salt to Hitec could accelerate the dissolution of Cr. Nevertheless, the formation of an inner Cr‐containing scale could still offer the alloy good protection because the external insoluble Ni or Fe oxides can protect it from dissolution. [ABSTRACT FROM AUTHOR]

In this research, corrosion inhibition of 2-(4-methoxyphenyl)-benzothiazole as a novel inhibitor was considered by electrochemical impedance spectroscopy (EIS). Obtained data from EIS were assessed to model the corrosion inhibition procedure over the equivalent circuit. Experimental design approach in the field of corrosion science was studied in this research. It is an essential step in studying the corrosion of mild steel data of multifaceted chemical systems to control the number of principal factors. The multivariate statistical design of experiments (DOE) method represents a hopeful and efficient optimization technique, which can overwhelm the limits of traditional optimization methods. Achieved optimum values by DOE were 25 °C, 0.001 M and 2 M for temperature, inhibitor and hydrochloric acid concentrations, respectively, which gave 97.8% inhibition efficiency. The inhibitory and adsorption of the inhibitor molecules were investigated by the quantum calculation and molecular dynamics (MD) simulation. The quantum calculations reveal suitable intrinsic molecular parameters of the inhibitor. MD simulations predicted the parallel orientation of the inhibitor on the Fe(110) surface and the proper adsorption energy. [ABSTRACT FROM AUTHOR]

The corrosion behavior of electrodeposited nickel-based coatings with W, Mo, and TiOx as potential catalytic material for hydrogen evolution reaction (HER) in highly aggressive media, 0.5 M H2SO4 and 6 M KOH, is presented. A wide range of electrochemical and spectroscopic methods have been used, such as linear sweep voltammetry, open-circuit potential (OCP), electrochemical impedance spectroscopy (EIS), X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS) to characterize the coatings before and after a residence time of 336 h in the model corrosion environment. The NiW alloy and the NiWTiOx composite coating demonstrate the best corrosion resistance in an acidic environment due to the stable tungstate phase formation (H0.33O3W and H2O4W) on the surface. In alkaline environments, all the systems studied show enviable resistance, but the alloys containing molybdenum stand out. [ABSTRACT FROM AUTHOR]

In this work, effect of varying lithium perchlorate (LiClO4) salt concentration in polymer gel electrolytes (PGE) containing heat resistant polymethyl methacrylate (PMMA), and succinonitrile (SN) is investigated via electrochemical and physical properties. The electrolyte specimen with high LiClO4 salt concentration of 1.5 M supports maximum ionic conductivity of 4.9 × 10–5 S cm−1 and electrochemical stability window of ~ 4 V. The ion-transport parameters evaluated from the tangent loss studies confirms that the optimized electrolyte possesses diffusivity (D) of 4.52 × 10–2, mobility (μ) of 1.746 cm2 V−1 s−1, number of charge carriers (N) of 1.78 × 1014 cm−3 and Nµ of 3.106 × 1014 cm−1 V−1 s−1. The dielectric constant studies show that the optimized electrolyte possesses maximum dielectric constant and lower value of modulus towards the high frequency region. The thermogravimetric and differential scanning calorimetry studies confirms that the prepared electrolytes offer weight loss of < 9% up to 373 K and maintains the gel phase up to 570 K, respectively. X-ray diffraction suggest that the PGE system becomes more amorphous with progressive addition of LiClO4 up to 1.5 M, while the Fourier transform Infra-red (FTIR) spectroscopy study reveal the salt-polymer interactions. [ABSTRACT FROM AUTHOR]

Na 3 Zr 2 Si 2 P 2 O 12 (NZSP) has potential use as a solid electrolyte in Na-ion solid-state batteries due to its high ionic conductivity (10−3–10−4 Scm−1) at room temperature. It is established that all previous preparations involving the solid-state method for NZSP compositions contain m -ZrO 2 as a secondary phase. Here, the solid-state method is used to prepare single-phase NZSP by modifying the mole fractions of the ZrO 2 reactant. Reducing ZrO 2 concentration may also create Zr and O vacancies and potentially increase the hopping sites for Na-ion conduction. X-ray diffraction, scanning electron microscopy, Raman and Fourier Transform Infrared spectroscopy, dilatometry and impedance spectroscopy were used to characterise the structure, morphology and electrical properties of single-phase NZSP, and the results were compared with samples that have m -ZrO 2 secondary phase (Na 3 Zr 2 Si 2 PO 12). The role of m -ZrO 2 impurities on the conductivity of NZSP is investigated and compared with available literature. [ABSTRACT FROM AUTHOR]

Miniaturized three‐electrode electrochemical sensors (MES) are widely used in the advancement of innovative technologies for remote sensing applications. MESs consist of conductive electrodes that are applied onto an inert solid substrate using various techniques, such as photolithography, electroplating, and screen printing. Typical MES systems comprise working (WE) and counter (CE) electrodes based on gold (Au), paired with a reference electrode (RE) based on silver (Ag). This configuration is commonly selected due to Au's high conductivity, low resistance, and compatibility with robust organothiol chemistries, especially for the WE. Moreover, Ag is often preferred for REs owing to its low toxicity, stability, and high conductivity. Nevertheless, in uncontrolled environments outside of cleanrooms, both Au and Ag surfaces are prone to atmospheric contamination, resulting in significant sensor variability and compromised analytical performance. Therefore, it is crucial to integrate a pre‐processing stage into the sensor manufacturing process to guarantee the quality and cleanliness of MES electrode surfaces for sensor functionalization and precise electrochemical measurements. Considering the potential negative effects of methods tailored for a specific electrode material on another material, this study extensively investigates 18 different treatment methods for MESs incorporating Au CEs and WEs, along with Ag REs. Employing a multi‐parametric analysis, this study aims to identify the most effective treatment for a variety of electrode materials, thereby improving analytical accuracy and reproducibility for subsequent MES (bio)sensor applications. [ABSTRACT FROM AUTHOR]

During the power operation of the primary loop of a water cooled–water moderated energy reactor (WWER), the water chemistry evolves from a high-boron high-potassium composition to significantly lower concentrations of both constituents at the end of a campaign, and the Li concentration reaches ca. 0.7–0.9 ppm. In the present paper, the effect of primary water chemistry evolution during operation on the corrosion rate and conduction mechanism of oxides on Alloy 690 is studied by in situ impedance spectroscopy at 300 °C/9 MPa during 1-week exposures in an autoclave connected to a re-circulation loop. At the end of exposure, the samples were anodically polarized at potentials −0.8 to −0.1 V vs. SHE to evaluate the stability of the passive oxide. Simultaneously exposed samples of Alloy 690 were subsequently analyzed by XPS to estimate the thickness and in-depth composition of oxides. Impedance data were quantitatively interpreted using the mixed-conduction model (MCM) for oxide films. The effect of water chemistry evolution on the corrosion rate and conduction mechanism in the oxide on Alloy 690 in a primary coolant is discussed based on the obtained parameters. [ABSTRACT FROM AUTHOR]

A new Mg-4Zn X Ti-6Al-4V (TC4, of 0, 1, and 3 wt.%) alloy was successfully fabricated by a simple and low-cost gravity casting method and heat treatment at 150 °C for 24 h. The composite was examined by XRD, uniaxial tests, FESEM/EDS, potentiostat/EIS, and immersion tests for the material's microstructures, mechanical properties, electrochemical characteristics, and corrosion resistance. Experimental results indicate that heat treatment enables the precipitation of Zn along the Mg grain boundaries and drives the co-precipitation of Al around the TC4 particles and nearby grain boundaries. Uniaxial tensile tests reveal that TC4 reinforces the Mg-Zn matrix material with higher elastic modulus, ultimate tensile stress, and toughness. The heat treatment further enhanced these mechanical properties. Electrochemical tests show that 1 wt.% TC4 composite exhibits the highest open circuit potential among all tested samples, which implies the 1 wt.% TC4-added Mg-Zn is better resistant to the oxidation of the essential metals Mg, Zn, and Al. The immersion tests in the HBSS solution further show that the 1 wt.% TC4 composite has the lowest rise of pH values after 14 days, and EDS for the corroded surface signifies that Mg is the main element vulnerable to oxidation by corrosion. [ABSTRACT FROM AUTHOR]

Biodiesel is a mixture of saturated and unsaturated Fatty Acid Methyl Esters (FAMEs) whose composition affects the corrosion behavior of metal containers during storage. This study examines the effect of the C=C bond present in selected FAMEs (Methyl Stearate, Methyl Oleate, and Methyl Linoleate) in aluminum corrosion in the absence of oxygen. First, mass loss assays were carried out at 100, 200, and 280 °C for 1000 h using pure Methyl Stearate (MS), 5% Methyl Oleate in Methyl Stearate (MS-5% MO), and 5% Methyl Linoleate in Methyl Stearate (MS-5% ML). Next, chemical changes in FAMEs were studied using FTIR, TGA, and GC/MS. SEM/EDS analysis allowed us to inspect the aluminum surfaces and their chemical characterization. We estimated higher corrosion rates for MS assays than those of unsaturated methyl ester mixtures. In a separate set of experiments, we used electrochemical techniques (potentiodynamic polarization, linear polarization resistance, and electrochemical impedance spectroscopy) to investigate aluminum corrosion induced by thermal-degraded products from FAMEs at 100, 200, and 280 °C for 300 h able to dissolve in aqueous extracts. These electrochemical experiments revealed that the products in the aqueous extracts from the unsaturated methyl ester mixture form a passive layer on the Al surface thicker than pure MS at the corresponding degradation temperatures. [ABSTRACT FROM AUTHOR]

Energy harvesting and energy storage are two critical aspects of supporting the energy transition and sustainability. Many studies have been conducted to achieve excellent performance devices for these two purposes. As energy‐storing devices, supercapacitors (SCs) have tremendous potential to be applied in several sectors. Some electrochemical characterizations define the performance of SCs. Electrochemical impedance spectroscopy (EIS) is one of the most powerful analyses to determine the performance of SCs. Some parameters obtained from this analysis include bulk resistance, charge‐transfer resistance, total resistance, specific capacitance, response frequency, and response time. This work provides a holistic and comprehensive review of utilizing EIS for SC characterization. Overall, researchers can benefit from this review by gaining a comprehensive understanding of the utilization of electrochemical impedance spectroscopy (EIS) for characterizing supercapacitors (SCs), enabling them to enhance SC performance and contribute to the advancement of energy harvesting and storage technologies. [ABSTRACT FROM AUTHOR]

Being an efficient approach to the utilization of hydrogen energy, the hydrogen oxidation reaction (HOR) is of particular significance in the current carbon‐neutrality time. Yet the mechanistic picture of the HOR is still blurred, mostly because the elemental steps of this reaction are rapid and highly entangled, especially when deviating from the thermodynamic equilibrium state. Here we report a strategy for decoding the HOR mechanism under operando conditions. In addition to the wide‐potential‐range I–V curves obtained using gas diffusion electrodes, we have applied the AC impedance spectroscopy to provide independent and complementary kinetic information. Combining multidimensional data sources has enabled us to fit, in mathematical rigor, the core kinetic parameter set in a 5‐D data space. The reaction rate of the three elemental steps (Tafel, Heyrovsky, and Volmer reactions), as a function of the overpotential, can thus be distilled individually. Such an undocumented kinetic picture unravels, in detail, how the HOR is controlled by the elemental steps on polarization. For instance, at low polarization region, the Heyrovsky reaction is relatively slow and can be ignored; but at high polarization region, the Heyrovsky reaction will surpass the Tafel reaction. Additionally, the Volmer reaction has been the fastest within overpotentials of interest. Our findings not only offer a better understanding of the HOR mechanism, but also lay the foundation for the development of improved hydrogen energy utilization systems. [ABSTRACT FROM AUTHOR]

The concentration effect of Tradescantia spathacea (T. spathacea) as corrosion inhibitor of API 5L X52 steel in 0.5 M of H2SO4 was studied here through electrochemical and gravimetric techniques. To achieve it, samples of the material were prepared to be submitted to each of the tests. Results from electrochemical impedance spectroscopy (EIS) showed that there was an optimum concentration of the inhibitor in which is reached the maximum inhibition efficiency, displaying the best inhibition characteristics for this system with a maximum inhibition of 89% by using 400 ppm. However, the efficiency decreased until 40% when the temperature was increased to 60°C. Potentiodynamic polarization curves (PDP) revealed that some of the present compounds of T. spathacea may affect anodic and cathodic process, so it can be classified as a mix-type corrosion inhibitor for API 5LX52 in sulfuric acid. Also, this compound followed an adsorption mechanism; this can be described through a Frumkin isotherm with an adsorption standard free energy difference (Δϋ") of -56.59 kJmol-1. Metal surface was studied through scanning electron microscope, results revealed that by adding inhibitor, the metal surface is protected; also, they evidenced low damages compared with the surface with no inhibitor. Finally, Tradescantia spathacea inhibited the corrosion process with 82% efficiency. [ABSTRACT FROM AUTHOR]

Despite the critical role of hydrogels in material science and biotechnology, current methods for analyzing their formation lack real‐time monitoring and require complex sample preparation and instrumentation. In this work, an innovative methodology is introduced for the real‐time analysis of enzymatically catalyzed hydrogelation. Electrochemical impedance spectroscopy (EIS) coupled with interdigitated electrodes (IDEs) to sense and transduce the gelation reaction of model precursor carboxymethyl cellulose‐tyramine (CMC‐TA) conjugates that undergoes enzymatic cross‐linking by horseradish peroxidase (HRP) and hydrogen peroxide (H2O2). Real‐time monitoring involves single‐frequency analyses at 3 × 105 Hz, where the measured impedance consists solely of a resistive component, and the admittance equates to solution conductance. The gelation trajectories for all tested enzymatically cross‐linked hydrogel component combinations are determined by substituting the conductance data in the modified Michaelis–Menten kinetic model. Specifically, for CMC‐TA cross‐linked by HRP, the authors calculate apparent KM and kcat values of 82.1 µM and 95.5 s−1, respectively. These findings are further validated through rheological characterization, including oscillatory shear measurements and microrheology. Overall, this research paves the way for a streamlined, accurate, and cost‐effective approach to controllable enzymatically initiated hydrogel synthesis, enhancing their successful application in various fields ranging from material science to biotechnology. [ABSTRACT FROM AUTHOR]

In this paper, the mechanism of proton exchange membrane fuel cell (PEMFC) cathode cycling is discussed and the high potential suppression control problem for fuel cell vehicles is investigated by using cathode cycling. Firstly, a rigorous single-cell experimental investigation is performed to reveal the impact mechanism of cathode recirculation on the internal polarization processes of PEMFC. Results show that an increase in the recirculation ratio leads to an increase in the polarization impedance in the low and medium frequency regions but decreases the ohmic impedance. Consequently, when the recirculation ratio increases to 1, the voltage drop rates are 2.2%, 3%, 4.6%, 5.8%, and 7% as the current density varies from 0 to 0.2 A/cm2, respectively, and the ohmic impedance decreases by 28.1%. On the basis, the optimal control scheme for high potential suppression based on cathode circulation in vehicular PEMFC system is proposed. The performance comparison of different control method is carried out on a software-in-the-loop testing platform. The results show that, for the same control objective, the model predictive control (T-S MPC) method is 55.5% and 16.7% lower than the proportional integral (PI) controller and the Takagi-Sugeno linear quadratic Gaussian (T-S LQG) in terms of controller input cost. On the contrary, the cumulative error of voltage tracking is reduced by 62% and 30.4% and the voltage response against disturbances is improved by 9.7% and 42.8%. Overall, the T-S MPC achieves the optimal control effect with less control effort. • An insight into the mechanism of cathode recirculation affecting PEMFC performance. • Cathode recirculation reduces ORR reaction rate and oxygen diffusion rate. • The T-S MPC provides optimal closed-loop control of high potential suppression. [ABSTRACT FROM AUTHOR]

Identifying and quantifying accessible nutrients in the soil are critical in agriculture since plants require particular amounts of micro and macronutrients to grow successfully. However, there is no well-defined method for quantifying macronutrients in the field at present. In this work, chitosan and chitosan-molybdate membranes were deposited onto stainless steel (SS) and carbon (C) substrates and evaluated as promising candidates for the quantification of phosphorous species available in cultivated soil. The membranes were morphologically and structurally studied by atomic force microscopy and infrared spectroscopy to determine their appearance, roughness, and chemical conformation. Electrochemical impedance spectroscopy was the electrochemical tool used to evaluate the quantification capacity of phosphorus species of the membrane-based electrodes; it was found that the chitosan-molybdate membranes deposited onto the SS/C interface presented the best performance when the electrodes change in charge transfer resistance and chemical capacitance were measured as a function of the concentration of phosphorus species available in a synthetic sample. Thus, based on the presented results, chitosan biosensors have shown the capability of attracting ionic species, which contributes to the minimization of preference zones on the surface of a sensing electrode. [ABSTRACT FROM AUTHOR]

The stem extract of Solanum Lycopersicum prepared using the methanol extraction method has been investigated as an environment-friendly inhibitor for low-carbon steel in monoprotic(1N HCl) and diprotic(1N H2SO4) solvents and characterized with FT-IR. A maximal inhibition efficiency of 81.8% in 1 N Hydrochloric acid and 92.92% in 1 N Sulfuric acid is assessed under a certain set of conditions of inhibitor concentration and temperature using weight loss, electrochemical impedance spectroscopy and potentiodynamic polarization. The results present Solanum Lycopersicum extract as a mixed-type inhibitor that predominantly influences the cathodic reaction and followed the Langmuir adsorption isotherm. Reduction in the value of average roughness (Ra)of the surface from 217 nm to 55 nm (in 1 N HCl) and 139.6 nm to 28 nm (in 1 N H2SO4) was observed with AFM after the application of the inhibitor which confirms the formation of a protective membrane and provides green inhibition on the low-carbon steel/solution interface. [ABSTRACT FROM AUTHOR]

Phytotoxins produced by marine microalgae, such as paralytic shellfish toxins (PSTs), can accumulate in bivalve molluscs, representing a human health concern due to the life-threatening symptoms they cause. To avoid the commercialization of contaminated bivalves, monitoring programs were established in the EU. The purpose of this work is the implementation of a PST transforming enzyme—carbamoylase—in an impedimetric test for rapid simultaneous detection of several carbamate and N-sulfocarbamoyl PSTs. Carbamoylase hydrolyses carbamate and sulfocarbamoyl toxins, which may account for up to 90% of bivalve toxicity related to PSTs. Conformational changes of carbamoylase accompanying enzymatic reactions were probed by Fourier transform mid-infrared spectroscopy (FT-MIR) and electrochemical impedance spectroscopy (EIS). Furthermore, a combination of EIS with a metal electrode and a carbamoylase-based assay was employed to harness changes in the enzyme conformation and adsorption on the electrode surface during the enzymatic reaction as an analytical signal. After optimization of the working conditions, the developed impedimetric e-tongue could quantify N-sulfocarbamoyl toxins with a detection limit of 0.1 µM. The developed e-tongue allows the detection of these toxins at concentration levels observed in bivalves with PST toxicity close to the regulatory limit. The quantification of a sum of N-sulfocarbamoyl PSTs in naturally contaminated mussel extracts using the developed impedimetric e-tongue has been demonstrated. [ABSTRACT FROM AUTHOR]

AbstractCurrent global 3D metal printing research is focused on powder bed fusion and direct energy deposition. Several materials are presently under research to assess their post-additive manufacturing properties, and to process them in industries using advanced manufacturing techniques. This study investigates the electrochemical, mechanical, and metallurgical properties of wire arc additively manufactured (WAAM) ER70S-6 alloy walls on AISI S235 plates, emphasizing ship component fabrication. The corrosion resistance of both materials is assessed through Electrochemical Impedance Spectroscopy and Potentiodynamic Polarization testing in a 3.5% NaCl solution. Surface and cross-sectional morphologies are analyzed using optical microscopy and scanning electron microscopy, while energy dispersive spectroscopy is employed to study the chemical composition of the corrosion products. Moreover, the hardness of the WAAM-deposited ER70S6 wall is found to be highest in the uppermost layers of deposition due to the presence of acicular ferrite and ferritic-bainite microstructure. Tensile and Charpy impact strength for AISI S235 and WAAM-deposited ER70S-6 exhibit similar performance at room and low temperatures. Interestingly, the WAAM sample demonstrates a 60% higher elongation than the AISI S235 sample. Hence, the findings from this experimental work suggest that WAAM-deposited carbon steel exhibits favourable corrosion resistance and comparable mechanical properties to AISI S235. Consequently, WAAM is emerging as a promising alternative to conventional manufacturing techniques for fabricating ship components, repairing and modifying hull structures, manufacturing nozzles, propeller blades, fin-like structures, structural components, and more. [ABSTRACT FROM AUTHOR]

The combination of TiO2 and Nb2O5 in thin films has proven promising for preventing the corrosion of AISI 304. The thin films are developed using sol–gel and dip‐coating techniques, followed by heat treatment. Morphological and X‐ray diffraction analyses indicate a predominant anatase phase in TiO2, and isomorphic substitution of up to 20% Nb occurs in the thin‐film composition. Phase segregation above 30% is observed. Electrochemical tests are conducted in a 2 mol L−1 HCl solution. Scanning electron microscopy reveals satisfactory thin film deposition on AISI 304 but shows the presence of regions with discontinuities. Polarization curves show a corrosion current of 128.72 μA for pure AISI 304, an average corrosion current of 0.34 μA for thin films, and an average of 6.44 μA for films with discontinuities. This significant reduction in current demonstrates the efficiency of the corrosion protection of the film at the studied concentrations because of the high corrosion inhibition percentages. Electrochemical impedance spectroscopy results suggest a high charge transfer resistance, indicating a lower corrosion rate in xTiO2 the yNb2O5 films compared to uncoated AISI 304. [ABSTRACT FROM AUTHOR]

Proton Exchange Membrane Water Electrolyzers (PEMEL) are promising for the production of green hydrogen, but costs have to be reduced and lifetime has to be improved. In this study we investigate PEMEL with low catalyst loading achieved by Atomic Layer Deposition (ALD) and 3D printing of the electrodes. Degradation processes were characterized and allocated using different electrochemical and physicochemical methods. The cell setup was optimized using Distribution of Relaxation Times Analysis (DRT) of the Electrochemical Impedance Spectroscopy (EIS) measurements and the long-term performance of the optimized cell was investigated using different electrolytes (sulfuric acid and deionized water). • PEMWE cells with a low catalyst loading and 3D printed electrode show high mass activity. • Cell configuration is optimized using electrochemical methods. • Cell degradation is shown by polarization curves and impedance measurements. • Degradation processes can be allocated using DRT analysis. [ABSTRACT FROM AUTHOR]

In this work, the effect of low air relative humidity on the operation of a polymer electrolyte membrane fuel cell is investigated. An innovative method through performing in situ electrochemical impedance spectroscopy is utilised to quantify the effect of inlet air relative humidity at the cathode side on internal ionic resistances and output voltage of the fuel cell. In addition, algorithms are developed to analyse the electrochemical characteristics of the fuel cell. For the specific fuel cell stack used in this study, the membrane resistance drops by over 39 % and the cathode side charge transfer resistance decreases by 23 % after increasing the humidity from 30 % to 85 %, while the results of static operation also show an increase of ∼2.2 % in the voltage output after increasing the relative humidity from 30 % to 85 %. In dynamic operation, visible drying effects occur at < 50 % relative humidity, whereby the increase of the air side stoichiometry increases the drying effects. Furthermore, other parameters, such as hydrogen humidification, internal stack structure, and operating parameters like stoichiometry, pressure, and temperature affect the overall water balance. Therefore, the optimal humidification range must be determined by considering all these parameters to maximise the fuel cell performance and durability. The results of this study are used to develop a health management system to ensure sufficient humidification by continuously monitoring the fuel cell polarisation data and electrochemical impedance spectroscopy indicators. • PEM Fuel cell inlet air relative humidity regulation using a passive humidifier with fuzzy logic control. • Using EIS characteristics to quantify the effect of air relative humidity on PEMFC performance. • Air RH affects PEMFC significantly depicted by mean cell voltage and internal resistances. • Electrochemical analyses using EIS oriented algorithms to develop a health management system. [ABSTRACT FROM AUTHOR]

In the present paper, the effect of the evolution of primary water chemistry during power operation on the corrosion rate and conduction mechanism of oxide films on stainless steel is studied by in situ impedance spectroscopy at 300 °C/9 MPa during 1-week exposure periods in an autoclave connected to a recirculation loop. At the end of the exposure period, the samples were anodically polarized in a wide range of potentials to evaluate the stability of the passive oxide. Separate samples of the same steel were simultaneously exposed to the coolant and subsequently analyzed by glow discharge optical emission spectroscopy (GDOES) in order to estimate the thickness and the in-depth composition of the formed oxides. Impedance data were quantitatively interpreted using the mixed-conduction model for oxide films (MCM) to estimate the rates of metal oxidation at the alloy/oxide interface, oxide dissolution and restructuring at the film/coolant interface, and ion transport in the protective corrosion layer. [ABSTRACT FROM AUTHOR]

Monitoring early stages of polymeric deposit formation and its prevention were studied by in‐situ electrochemical impedance spectroscopy (EIS) in a continuously operating reactor employed for polymer production. An EIS flow cell was designed and employed during the emulsion polymerization of vinyl acetate. The electrochemical analysis of the complex impedance at the solution/reactor interface allows the time‐resolved detection of film formation processes. In comparison to oxide‐covered stainless steel, an anti‐adhesive sol‐gel coated alloy showed a significant inhibition of poly(vinyl acetate) fouling. The EIS‐based approach proved to be a valuable tool for monitoring both thin barrier film performance and fouling processes under harsh process conditions. [ABSTRACT FROM AUTHOR]

The addition of dry ice as an admixture to cement pastes has many advantages such as improving the compressive strength and sequestration of CO2. However, its effect on the hydration mechanism of cement pastes is still unknown and will be investigated using electrochemical impedance spectroscopy in this paper. Based on the linear correlation of cumulative hydration heat from the isothermal calorimetry test and the logarithm of high-frequency resistivity, a modified Knudson equation is derived. Corresponding hydration kinetic parameters are calculated by applying the boundary nucleation and growth theory and kinetics model, including Avrami, geometrical contraction, and diffusion equations. The boundary area per unit volume (OvB) for the control specimen and specimens with 0.2% and 0.5% cement weight dry ice addition is 0.1171, 0.1250, and 0.1562, respectively, indicating that the dry ice addition increases the surface area of the nucleation process. In addition, the results show that the Avrami equation for monitoring the nucleation process is limited. Regarding the hydration curves, the transition from the nucleation and growth stage to the interaction of phase boundaries (I) stage is delayed by adding dry ice to the mixture. [ABSTRACT FROM AUTHOR]

Porous carbon-supported CoFe-layered double hydroxide (LDH)-based catalysts were synthesized and utilized as excellent oxygen evolution reaction catalysts in alkaline medium. High-resolution transmission electron microscopy images and N2-sorption experiments suggested vertical growth of LDH on the carbon support and a narrow mesoporous nature of the materials, respectively. We proposed that the surface oxygen functional groups of carbon materials provided the nucleation sites for the crystal growth of the LDH on the carbon support utilizing short-range electrostatic interactions, which led to vertical growth of LDH with a narrow mesoporous nature. Among the synthesized materials, CoFe-LDH/MMC showed a remarkable mass activity of 559.2 A g–1, a turnover frequency of 4.22 s–1, and a massive roughness factor value of 269. This excellent reactivity has been attributed to (a) the vertically aligned narrow mesoporous nature of the material that increased the electrolyte accessibility inside the material and thus improved active sites for catalysis, (b) the high electrical conductivity of the material that also enhanced accessibility, reduced resistance for charge transfer at the electrode/electrolyte interface, and reduced resistance for intermediate formation during water oxidation, and (c) the increased electron contribution to the 3d orbital of cobalt from carbon that weakened the Co–oxygen bond and thus further facilitated the formation of the O–O bond and O2 desorption during water oxidation. [ABSTRACT FROM AUTHOR]

In the era of Industry 4.0, achieving optimization in production and minimizing environmental impact has become vital. Energy management, particularly in the context of smart grids, plays a crucial role in ensuring sustainability and efficiency. Lithium-ion batteries have emerged as a leading technology for energy storage due to their versatility and performances. However, accurately assessing their State of Health (SOH) is essential for maintaining grid reliability. While discharge capacity and internal resistance (IR) are commonly used SOH indicators, battery impedance also offers valuable insights into aging degradation. This article explores the use of Electrochemical Impedance Spectroscopy (EIS) to define the SOH of lithium batteries. By analyzing impedance spectra at different frequencies, a comprehensive understanding of battery degradation is obtained. A life cycle analysis is conducted on cylindrical Li–Mn batteries under various discharge conditions, utilizing EIS measurements and an Equivalent Circuit Model (ECM). This study highlights the differential effects of aging on battery characteristics, emphasizing the variations at different life stages and the behavior changes on each region of the impedance spectrum. Furthermore, it demonstrates the efficacy of EIS and the advantages of this technique compared to the solely IR measurements used in tracking SOH over time. This research contributes to advancing the understanding of lithium battery degradation and underscores the importance of EIS in defining their State of Health for Smart Grids applications. [ABSTRACT FROM AUTHOR]

Polypyrrole–oxalate (PPy-O) electrodes were electropolymerized from the oxalate solutions containing oxalic acid and pyrrole (Py) monomer. The structural, electrochemical and capacitive behaviors were studied depending on the monomer concentration, the applied current density and the film thickness. PPy-O has very ordered structural and electronic properties. The specific capacitance value was found as 657.1 F/g, but the lifetime was very short. Polypyrrole–sulfate (PPy-S) electrodes were electropolymerized from the sulfate solutions containing sulfuric acid and Py monomer. They were investigated as a function of the monomer concentration and the applied current density. The PPy-S electrodes are in disordered structure. The highest specific capacitance value was found as 1066.7 F/g. A symmetric capacitor was fabricated from PPy-S electrodes. The energy density is 26.4 Wh/kg and power density is 155.4 W/kg. Those supercapacitors are convenient to use for devices working at a low-medium power density. [ABSTRACT FROM AUTHOR]

In low‐temperature environment, the residual water in the membrane electrode assembly (MEA) will freeze after the operation of proton exchange membrane fuel cells, which will cause damage to the MEA. In this paper, the effect of freeze–thaw cycles on MEA was studied. Six sets of MEA samples with 0, 20, 40, 60, 80, and 100 times freeze–thaw cycles were set up, and the damage on MEAs is analyzed by polarization curves, electrochemical impedance spectra, cyclic voltammetry curves, and scanning electron microscope. It was found that the freeze–thaw cycles caused degradation on MEA, and the ohmic resistance of MEA increases with the number of cycles increases before the 60 freeze–thaw cycles, and after 60 freeze–thaw cycles, a gap appeared between the proton exchange membrane (PEM) and the catalyst layer, which led to more water entering the PEM and the ohmic resistance of MEA decreased. Besides, according to the data analysis, the experimental samples are divided into three categories (normal MEA, lightly damaged MEA, and seriously damaged MEA). A classifier model combining inception network and light gradient boosting machine (LGBM) was established, and it was found that the combined model was better than inception–dense and LGBM for classification, reaching 96.89%. [ABSTRACT FROM AUTHOR]

The proton exchange membrane fuel cell (PEMFC) stands at the forefront of advancing energy sustainability. Effective monitoring, control, diagnosis, and prognosis are crucial for optimizing the PEMFC system's sustainability, necessitating a dynamic model that can capture the transient response of the PEMFC. This paper uses a dynamic fractional-order model to describe the behaviors of a stationary micro combined heat and power (mCHP) PEMFC stack. Based on the fractional-order equivalent circuit model, the applied model accurately represents the electrochemical impedance spectroscopy (EIS) and the dynamic voltage response under transient conditions. The applied model is validated through experiments on an mCHP PEMFC stack under various fault conditions. The EIS data is analyzed under different current densities and various fault conditions, including the stoichiometry of the anode and cathode, the stack temperature, and the relative humidity. The dynamic voltage response of the applied model shows good correspondence with experimental results in both phase and amplitude, thereby affirming the method's precision and solidifying its role as a reliable tool for enhancing the sustainability and operational efficiency of PEMFC systems. [ABSTRACT FROM AUTHOR]

Flexible polymer electrolytes with efficient electrochemical characteristics were necessary to meet the requirements of smart electronics technology and foldable electronics. It is both important and difficult to design and construct a flexible lithium polymer electrolyte with higher ionic conductivity and better dielectric properties for use in electrochemical storage devices because of the need to increase storage capacity and electrochemical stability. This research describes the inclusion of Nickel oxide nanoparticles (n-NiO), which are environmentally benign, doped lithium flexible polymer electrolytes (n-FLPEs), via the solution-cast method with polymer matrices of poly (vinylidene fluoride-hexafluoropropylene) (PVdF-HFP), poly (ethylene oxide) (PEO), which is a biodegradable polymer, as well as Lithium trifluoromethanesulfonate (LiCF3SO3). When n-NiO is incorporated into FLPEs, the ionic conductivity increases by a factor of nearly four and a half. The εʹmax value increased four times, and ε″max value increased seventeen times owing to n-NiO inclusion. We used cyclic voltammetry (CV) and chronoamperometry (CA) to study the charge carrier buildup, ionic strength, and transference number in the optimal n-FLPE membrane. n-FLPEs have been shown to be electrochemically stable and capable of transporting ions due to chemical shifts in functional groups illustrated by X-ray photoelectron spectroscopy (XPS) investigations. The significance of the [υs(SO3)] mode in ionic conductivity has been extensively addressed. We analysed the FESD's discharging behaviour at a 0.04 C assessment, or an average current during discharge of 5.128 mA over 25 h. [ABSTRACT FROM AUTHOR]

In this study, we employed classic electrochemical techniques including cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) to perform electrochemical characterization on atomic-level single-crystal TiO2 electrodes and extract capacitive and resistive properties of single-crystal TiO2 electrode/solution interface in KCl and KCl/K3PO4 at various pH levels. The lattice structure and crystal appearance were characterized using X-ray diffractometry (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy to facilitate the in-depth exploration of heterogeneous reaction dynamics and theory. Furthermore, this study aimed to verify and improve the theory and application of capacitance at the single-crystal TiO2 electrode/solution interface. The electrochemical measurements indicate that, in the same pH, the presence of PO43− significantly increases the total capacitance (CT), outer capacitance (CO), electrical double-layer capacitance (Cdl), and diffusion layer capacitance (Cdiff) at single-crystal TiO2 electrode/solution interface. This enhancement is attributed to the direct interaction between PO43− and the single-crystal TiO2 electrode surface, leading to the specific adsorption of PO43− on the electrode surface, revealing higher current and stronger electrochemical activity in the interaction between TiO2 and PO43−. Additionally, our XPS results indicate the adsorption of PO43− on the single-crystal TiO2 electrode surface. The interaction of PO43− with the TiO2 surface demonstrates increased hydrophilicity and enhanced adsorption capacity through mechanisms such as ligand exchange or cation bridging, thereby augmenting the Cdl at the single-crystal TiO2 electrode/solution interface. [ABSTRACT FROM AUTHOR]

In this work, a comparative study is presented utilizing a K+ conducting gel polymer electrolyte (GPE) system comprising of a poly(vinylidene fluoride-hexafluoropropylene) (PVdF-HFP) polymer matrix combined with potassium permanganate (KMnO4) salt and two different plasticizers as a binary combination of ethylene carbonate (EC) + propylene carbonate (PC) and tetraethylene glycol dimethyl ether (TEGDME). The electrolyte with TEGDME solvent shows an ionic conductivity (σ) of 7.01 × 10−6 S cm−1 with hopping of ions as charge transport behavior. The fabricated electrolyte possesses > 98% contribution from the ions, and the electro-chemical stability range is up to 3.2 V. The dielectric analysis shows that the electrolyte with TEGDME solvent possesses a higher value of the dielectric constant, dielectric loss, tangent loss, and dc conductivity, along with a higher free ion number density (N) in comparison to the counter-electrolyte specimens with EC:PC solvent. The thermal studies confirm the gel phase of both electrolytes with negligible weight loss till 100 °C. Polymer-salt complex interactions are confirmed using Fourier transform infrared spectroscopy (FTIR), while X-ray diffraction (XRD) analysis is used to study the variations in crystallinity brought about by the polymer and both electrolyte samples. [ABSTRACT FROM AUTHOR]

Electrochemical impedance spectroscopy (EIS) is a measurement method widely used for non-destructive analysis and diagnostics in various electrochemical fields. From the measured dependence of the battery impedance on the frequency, it is possible to determine the parameters of various equivalent electrical circuit models of the battery. The conventional method of battery measurement using single-sine EIS is currently one of the most widely used methods for the analysis of lithium-ion batteries. However, its most significant disadvantage is the relatively long measurement time. For this reason, there is a growing demand for faster methods using fast-Fourier transform or pseudo-random sequences. A description of various EIS methods applications is provided in this paper. [ABSTRACT FROM AUTHOR]

In this study effect of Ni single-layer coating and Ni/Cr bilayer coating on room temperature corrosion of Sm2Co17 substrate in 3.5wt% NaCl solution was extensively performed. However, severe pitting corrosion occurred to the bare Sm2Co17 substrate and resulted in formation of cracks. Ni coating had good adhesion to the Sm2Co17 substrate but could not effectively improve the corrosion resistance of the substrate due to its porous nature. The Ni/Cr bilayer-coated magnet exhibited excellent corrosion resistance due to the prevention of Cl− ions penetration by the Cr coating. Additionally, no prominent negative effect on magnetic properties was evidenced after Ni or Ni/Cr coating. Hence, based on above-mentioned outcome Ni/Cr coating above Sm2Co17 magnet is potentially recommended to mitigate the corrosion problem of permanent magnets operating in marine conditions. [ABSTRACT FROM AUTHOR]

Ti-6Al-4V selective dissolution occurs in vivo on orthopedic implants as the leading edge of a pitting corrosion attack. A gap persists in our fundamental understanding of selective dissolution and pre-clinical tests fail to reproduce this damage. While CoCrMo clinical use decreases, Ti-6Al-4V and the crevice geometries where corrosion can occur remain ubiquitous in implant design. Additionally, most additively manufactured devices cleared by the FDA use Ti-6Al-4V. Accelerated preclinical testing, therefore, would aid in the evaluation of new titanium devices and biomaterials. In this study, using temperature, we (1) developed an accelerated pre-clinical methodology to rapidly induce dissolution and (2) investigated the structure-property relationship between the dissolving surface and the oxide layer. We hypothesized that solution temperature and H 2 O 2 concentration would accelerate oxide degradation, increase corrosion kinetics and decrease experimental times. To assess this effect, we selected temperatures above (45 °C), below (24 °C), and at (37 °C) physiological levels. Then, we acquired electrochemical impedance spectra during active β dissolution, showing significant decreases in oxide polarization resistance (R p) both over time (p = 0.000) and as temperature increased (p = 0.000). Next, using the impedance response as a guide, we quantified the extent of selective dissolution in scanning electron micrographs. As the temperature increased, the corrosion rate increased in an Arrhenius-dependent manner. Last, we identified three surface classes as the oxide properties changed: undissolved, transition and dissolved. These results indicate a concentration and temperature dependent structure-property relationship between the solution, the protective oxide film, and the substrate alloy. Additionally, we show how supraphysiological temperatures induce structurally similar dissolution to tests run at 37 °C in less experimental time. Within modular taper junctions of total hip replacement systems, retrieval studies document severe corrosion including Ti-6AL-4V selective dissolution. Current pre-clinical tests and ASTM standards fail to reproduce this damage, preventing accurate screening of titanium-based biomaterials and implant designs. In this study, we induce selective dissolution using accelerated temperatures. Building off previous work, we use electrochemical impedance spectroscopy to rapidly monitor the oxide film during dissolution. We elucidate components of the dissolution mechanism, where oxide degradation precedes pit nucleation within the β phase. Using an Arrhenius approach, we relate these accelerated testing conditions to more physiologically relevant solution concentrations. In total, this study shows the importance of including adverse electrochemical events like cathodic activation and inflammatory species in pre-clinical testing. [Display omitted] [ABSTRACT FROM AUTHOR]

A microbial electrolysis cell integrated in an anaerobic digestion system (MEC-AD) is an efficient configuration to produce methane from an exhausted vine shoot fermentation broth (EVS). The cell worked in a single-chamber two-electrode configuration at an applied potential of 1 V with a feeding ratio of 30/70 (30% EVS to 70% synthetic medium). In addition, an identical cell operated in an open circuit was used as a control reactor. Experimental results showed similar behavior in terms of carbon removal (70–76%), while the specific averaged methane production from cycle 7 was more stable and higher in the connected cell (MECAD) compared with the unpolarized one (OCAD) accounting for 403.7 ± 33.6 L CH4·kg VS−1 and 121.3 ± 49.7 L CH4·kg VS−1, respectively. In addition, electrochemical impedance spectroscopy revealed that the electrical capacitance of the bioanode in MECAD was twice the capacitance shown by OCAD. The bacterial community in both cells was similar but a clear adaptation of Methanosarcina Archaea was exhibited in MECAD, which could explain the increased yields in CH4 production. In summary, the results reported here confirm the advantages of integrating MEC-AD for the treatment of real organic liquid waste instead of traditional AD treatment. [ABSTRACT FROM AUTHOR]

The effects of thallium(I) ions on the surface morphology, cathode current efficiency, cathode potential, polarization behavior, and electrochemical impedance spectroscopy of zinc electrowinning were studied by scanning electron microscopy and electrochemical measurements. The results showed that with increasing thallium(I) ion concentration in the electrolyte, the hydrogen evolution reaction and the galvanic effect produced during zinc electrowinning increased. When the concentration of thallium(I) ions in the electrolyte was 0.6 mg L-1, the exchange current density of the zinc electrowinning process was maximum and the polarization was minimum. At this time, the Rct of the equivalent circuit was minimum, the CPE value was minimum, and the charge transfer rate was maximum. The cathodic current efficiency decreased from 80% to 55% when the thallium(I) ion concentration was 1.5 mg L-1. The presence of thallium(I) ions also affected the surface macro- and microstructure of the zinc deposits. This result confirmed that thallium(I) ions have a significant negative influence on the electrowinning of zinc. [ABSTRACT FROM AUTHOR]

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Effectively extracting a lithium-ion battery's impedance is of great importance for various onboard applications, which requires consideration of both the time consumption and accuracy of the measurement process. Although the pseudorandom binary sequence (PRBS) excitation signal can inject the superposition frequencies with high time efficiency and an easily implementable device, processing the data of the battery's impedance measurement is still a challenge at present. This study proposes a fast impedance spectrum construction method for lithium-ion batteries, where a multi-density clustering algorithm was designed to effectively extract the useful impedance after PRBS injection. According to the distribution properties of the measurement points by PRBS, a density-based spatial clustering of applications with noise (DBSCAN) was used for processing the data of the lithium-ion battery's impedance. The two key parameters of the DBSCAN were adjusted by a delicate workflow according to the frequency range. The validation of the proposed method was proved on a 3 Ah lithium-ion battery under nine different test conditions, considering both the SOC and temperature variations. [ABSTRACT FROM AUTHOR]