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Improving the reaction interface is imperative for increasing catalyst utilization and enhancing overall cell performance in proton exchange membrane electrolyzer cells (PEMECs). Herein, a thin Nafion-carbon-mixed microporous layer coated carbon paper (Nafion-C MPL/CP) is first developed as an efficient cathode liquid/gas diffusion layer for PEMECs. With the Nafion-C MPL/CP, low cell voltages of 1.64, 1.74 and 1.84 V are delivered, which are 50, 80 and 140 mV lower than those of the conventional bare carbon paper at 2, 4 and 6 A/cm2, respectively, achieving about 3-fold higher catalyst utilization. Meanwhile, superior performance is also demonstrated compared to the commercial PTFE-C MPL/CP. The remarkable performance of the Nafion-C MPL/CP should be attributed to the enhanced reaction interface, which not only provides rich active sites with abundant electron and proton transport pathways for the electrochemical reaction but also reduces the interfacial contact resistance and mass transport losses. Moreover, excellent stability of the Nafion-C MPL/CP is demonstrated at a current density of 1.8 A/cm2 with no performance degradation during over 100-h operation. Due to the enhanced reaction interface with significantly improved catalyst utilization, the developed Nafion-C MPL/CP shows great potential to reduce the hydrogen production cost and accelerate PEMEC commercialization. [ABSTRACT FROM AUTHOR]

To further enhance the long-term durability of the cost-effective Ir-based catalysts, some acid-stable oxides are used as supports for acidic OER catalysts. Herein, taking carbon paper (CP) as the substrate, we prepared a self-standing IrW/WO 3-x @NC/CP electrode via a layer-by-layer modified method. Among it, N-doped porous C framework not only provides a large specific surface for the attachment of WO 3-x , but also makes up for the lack of conductivity of WO 3-x and accelerates the electron transport process. The interaction between Ir and W sites in the form of IrW alloy which has generated during the high-temperature calcination and the dispersed Ir in WO 3-x matrix improve the intrinsic catalytic activity. And due to the Pt-like effect of W and the tuning role of the electronic structure by the IrW alloy, IrW/WO 3-x @NC/CP with an Ir content of only 19.1 µg cm−2 exhibits excellent bifunctional activity in acidic media. To obtain 10 mA cm−2, IrW/WO 3-x @NC/CP just needs overpotential of 22 mV (for HER) and 206 mV (for OER) respectively with a mass specific activity of 4.008 A mg Ir −1 at 1.55 V. For the whole water splitting, it only requires 1.52 V and 1.70 V to reach 10 mA cm−2 and 100 mA cm−2 respectively, and can operate continuously for over 40 h. [ABSTRACT FROM AUTHOR]

In this work, the direct current vs. voltage (DC) characteristics, and the alternate current (AC) impedance of a 1D four-electrode electrochemical cell, operating under redox-cycling conditions, are presented and discussed. The analysis refers to a four-electrode electrochemical system with one positively biased working electrode, one negatively biased working electrode, one auxiliary electrode, and one reference electrode operating in a redox cycling mode. This configuration is useful, for example, for electrochemical biosensors that can benefit from the inherent redox-cycling amplification of the apparatus. An aqueous buffered electrolyte is assumed, containing electrochemically active species that can be oxidized on the anode, with a positive overpotential. Meanwhile, the product of the oxidation reaction can diffuse to the other working electrode which has a negative overpotential, where the product is reduced. The analysis in this paper assumes that oxidation is the dominant mechanism at the anode, reduction is the dominant mechanism at the cathode, and the transport between them is dominated by diffusion. Since it is a 1D model, an ideal lossless redox cycling, i.e. both working electrodes' currents (anodic and cathodic) are of the same magnitude with opposite signs, is assumed. Next, the small signal (AC) impedance of the electrochemical cell was calculated assuming that the AC signal modifies the oxidation reaction rate at the anode while the reduction reaction rate at the cathode is fixed. The impedance under redox cycling is calculated vs. frequency for various oxidation and reduction rates and both Bodé and Nyquist plots of the impedance are presented. The last part of the paper presents measured data for both DC and AC (i.e. Bodé and Nyquist plots) experiments with interdigitated array (IDA) electrodes, 5 & 10 μm spacing, operating under redox cycling conditions. The DC measurements were conducted in a 6 mM ferricyanide [K 3 Fe(CN) 6 ] in 0.1 M Phosphate Buffer Saline (PBS) solution, pH 7.4. The AC measurements were conducted in 10 mM & 100 nM ferricyanide (K 3 Fe(CN) 6) in 100 mM KNO 3 aqueous electrolyte. A critical discussion follows the results section where the highlights and problems of the models are discussed. [ABSTRACT FROM AUTHOR]

• An unsupervised feature extraction method of Li-ion batteries' EIS is proposed. • The latent variables are extracted automatically without prior knowledge. • The extracted latent variables are related to battery aging. • The capacity of batteries for uneven usage during degradation is estimated. • The proposed method generates reliable EIS data. In this paper, we propose an unsupervised feature extraction technique using a variational autoencoder and generative adversarial network (VAEGAN) that automatically extracts meaningful latent variables from the electrochemical impedance spectra (EIS) of lithium-ion (Li-ion) batteries. These variables accurately reflect the degree of Li-ion battery degradation and are closely related to its capacity. By analyzing the latent variables, it was found that the network can learn the effect of Li-ion battery capacity degradation on the EIS. The extracted latent variables are then used as input features for Gaussian Process Regression (GPR) to estimate the capacity of Li-ion batteries under uneven usage and with unknown historical data. The results show that the capacity prediction method proposed in this paper can significantly reduce prediction errors compared to the current state-of-the-art methods. The method not only provides a more reliable capacity estimation but is also robust to highly noisy EIS data, making it more suitable for practical application scenarios. [Display omitted] [ABSTRACT FROM AUTHOR]

• The proposed method can detect lithium plating earlier in the charging process. • Compared with other methods, this method is more sensitive and simple. • Combined with the model, the source of lithium plating signal is analyzed. • The universality of the method is verified by model simulation. Lithium plating is one of the most severe problems threatening the durability and safety of lithium-ion batteries. Therefore, accurate detection of lithium plating is crucial for the health management and charging control of lithium-ion batteries. In this paper, an impedance-based method is proposed to detect lithium plating of lithium-ion battery by comparing the normalized charing internal resistance profiles. After verifying that the model-based method is effective and feasible, it was used to analyze the reason and internal mechanism of the detection signal compared with the more frequently used lithium plating detection procedures today. The proposed detection method is more sensitive and accurate and expected to detect lithium plating in real-time during the charging process. Finally, the model showed that the method remained effective and reliable for lithium plating detection when the charging conditions changed. This paper, through the analysis, simulation, and experimental verification of online lithium plating detection method based on charging internal resistance, provides innovative ideas for the subsequent development of lithium plating detection and stimulates potential technologies for future development. [ABSTRACT FROM AUTHOR]

• Development of a dual-templated molecularly imprinted electrochemical sensor for the simultaneous analysis of brilliant blue FCF and tartrazine. • MIP film was generated by electro-polymerization of 3-aminophenyl boronic acid with brilliant blue and tartrazine as templates. • High surface area modification enables the formation of complementary binding sites for both analytes on the MIP sensor surface during fabrication. • Successful application of the developed sensor in real food samples. In this study, a dual-templated molecularly imprinted polymer-based electrochemical sensor was developed for the simultaneous analysis of two food additive dyes, brilliant blue FCF and tartrazine. Using a 3-aminophenyl boronic acid (3-APBA) monomer and the dual templates of brilliant blue FCF (BB) and tartrazine (TZ), the molecularly imprinted polymer (MIP) layer was electropolymerized on the carbon fibre paper (CFP) electrode. By using BB and TZ as template molecules along the electro-polymerization of 3-APBA, then removing both template molecules, the MIP film was generated on the surface of the CFP electrode. Due to the high surface area provided by modification, several complementary binding sites for template molecules are formed on the surface of the MIP sensor during this process of sensor fabrication. On the MIP/CFP electrode, the electrochemical behavior of BB and TZ was assessed. The monomer/template ratio, pH values, and influencing parameters like the electro-polymerization scanning cycles were all optimized. This sensor was applied to detect brilliant blue FCF and tartrazine in beverage and food samples using MIPAPBA/CFP electrode. [Display omitted] Graphical representation of the sensor fabrication process [ABSTRACT FROM AUTHOR]

Lithium-ion battery (LIB) occupies a major position in rechargeable batteries. However, if the state of charge (SOC) estimation of LIB is not accurate, it will lead to the decline of battery life. SOC is often estimated by the extended Kalman filter (EKF) algorithm, but this method depends on the accuracy of model parameters. The sampling point interval time can affect the accuracy of SOC estimation. In this paper, the first-order RC model parameters are identified by two methods and the SOC is estimated by the EKF algorithm. Using this method, the battery parameters are received more accurate and the SOC estimation error is smaller. When the sampling interval is 0.03 s, the SOC estimation error is the smallest. And the second-order RC model can receive the same result. When the sampling interval is 0.03 s, the SOC estimation error of the 1RC-1 method is less than 1.4 %, the SOC estimation error of the 1RC-2 method is less than 0.017, and the root mean square error (RMSE) is 0.0087 and 0.01084. The conclusion is also used in the second-order RC model and contributes to the improvement of the SOC estimation accuracy. An effective method to estimate the battery SOC range is also proposed. This paper provides an effective method for obtaining more accurate SOC. [ABSTRACT FROM AUTHOR]

This paper presents an exhaustive how-to guide on measuring the total vanadium concentration and state of charge of vanadium electrolytes using UV–Visible spectroscopy. The study is provided with an open-access database (GitHub) that supports the methods and procedures and facilitates access to the calibration data. The study covers the three types of electrolyte solutions relevant to vanadium redox flow batteries, namely the anolyte V II / V III , the catholyte V IV / V V , and the V III / V IV commercial electrolyte, meant to be preconditioned to either V III or V IV before battery operation. Analytical expressions to calculate the concentration of different vanadium species in the electrolyte solutions are provided based on either empirical correlations or spectral deconvolution methods. The paper also examines the limitations of the measurement technique and provides insightful recommendations for future research. The open-access database provided by the authors is expected to serve as a valuable repository for scholars and scientists working in the field of vanadium redox flow batteries. • UV–Visible spectroscopy is used to characterize vanadium electrolytes. • We studied the anolyte V II / V III , the catholyte V IV / V V , and V III / V IV . • An empirical method and a deconvolution method are proposed for each electrolyte. • The methods are calibrated over a wide range of concentrations (0.91–1.83M). • Total vanadium concentration and state of charge can be accurately measured. • Accuracy is 25–35 mM for the concentration and 1.0–1.5% for the state of charge. [ABSTRACT FROM AUTHOR]

• Different carbon-based electrodes following a nature-inspired solution were tested by CV and EIS. • Glass-carbon electrodes (GCE) and carbon paper-based electrodes (CPE) with and without polytetrafluoroethylene (PTFE) were evaluated. • The electrodes' performance was assessed by employing the ferri/ferrocyanide ([Fe(CN) 6 ]3-/4−) electrochemical probe. • Surface properties of the commercial electrodes materials were evidenced from AFM and water contact angle measurements. • Best results were achieved with CPE without PTFE, given its hierarchical porous structure and absence of the insulating binder. Carbon electrodes are widely accepted as very versatile platforms, with applications ranging from electrocatalysis to sensors and other devices, like fuel cells and water electrolyzers. However, there are still difficulties given that over time, at high potentials, the oxidation of carbon materials (as a catalyst and/or catalyst support) can play a detrimental role, undermining the efficiency and stability of the electrochemical processes and devices performance. In this paper, it is reported the research work followed by resourcing to electrochemical analytical techniques, like cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), along with complementary atomic force microscopy (AFM) and water contact angle (WCA) measurements. These techniques were used to characterise glass-type and paper-based carbon electrodes. On a nature-inspired solution, we took advantage of the different interfacial carbon-support hierarchical porous structures to boost the carbon electrocatalytic effect towards sensing the ferri/ferrocyanide redox couple ([Fe(CN) 6 ]3-/4−) in aqueous solution. It is shown that the best results were achieved with carbon paper electrodes without wet proofing, given its hierarchical porous structure and absence of the insulating binder. This research endeavors to contribute to the ongoing advancements in the field of electrochemical green energy conversion by exploring innovative approaches and materials, with the ultimate aim of developing carbon substrates that not only enhance performance but also promote environmental sustainability. [Display omitted] [ABSTRACT FROM AUTHOR]

• The basic model of high C-rate is determined by the model configuration analysis. • Sampling frequency and time domain influences model parameters are analyzed. • A model parameter correction method based on the rule of different overpotentials is proposed. • A modified high C-rate model is innovatively established with current dependence and concentration modification. • The modified model is validated up to the 6C rate at different temperature. The current battery equivalent circuit models are mainly suitable for room temperature or low C-rate conditions. However, the polarization phenomenon is serious at high C-rate, which results in the obvious voltage drop and significantly reduces the model accuracy at high C-rate. In this paper, the characteristics analysis of different RC models is firstly studied. It is found that the first-order RC circuit model is more suitable for high C-rate conditions due to the coupling of model parameter extraction. Based on the first-order RC model, a basic equivalent circuit model adapted to high C-rate condition is then determined. Secondly, the influences of sampling frequency and the identified time domain on instantaneous impedance and polarization resistance are researched. Thirdly, the change rules of different polarizations at high C-rate are analyzed. Furthermore, the relationship between the change rule of the model parameters and that of different overpotentials are researched. Subsequently, a modified high C-rate model is innovatively established, which considers the current dependence and concentration/temperature modification of instantaneous impedance and polarization resistance. Finally, the accuracy of the modified high C-rate model is verified at 5 °C, 25 °C, and 55 °C, respectively. Results show that the modified high C-rate model can improve the simulation accuracy of the voltage at high C-rate (≤6C), and the mean absolute error (MAE) and Root Mean Squared Error (RMSE) are within 68 mV. Compared with the existing high C-rate model, the accuracy of the modified high C-rate model proposed in this paper is improved and the complexity is also significantly reduced. [ABSTRACT FROM AUTHOR]

Two-dimensional nanolayered Mo 2 CT x is an excellent electrode material due to its large surface area and high conductivity. In this paper, Mo 2 C powders and metal Ga with the molar ratio of 1:3 as raw materials were used to prepare phase-pure Mo 2 Ga 2 C ceramic materials by non-pressure sintering at 750 °C, and two-dimensional nano-layered Mo 2 CT x materials were etched successfully using a facile oil bath method by HF. Capacitive behaviors of flexible and freestanding Mo 2 CT x film electrode prepared by the facile vacuum filtration in 1 M H 2 SO 4 , 1 M Na 2 SO 4 and 1 M NaOH electrolytes were systematically investigated for the first time. Mo 2 CT x film electrode exhibits the pseudo-capacitive behavior in H 2 SO 4 electrolyte, while double layer capacitance is presented in Na 2 SO 4 and NaOH electrolytes. The maximum volumetric specific capacitance of 563.05 F/cm3 at 2 mV/s is in H 2 SO 4 electrolyte, corresponding to the mass specific capacitance of 154.26 F/g. This is due to the obvious redox reaction in sulfuric acid solution Notably, density functional theory (DFT) calculation was executed to investigate the capacitive behavior and mechanism of the Mo 2 CT x film electrode in the three different electrolytes. [ABSTRACT FROM AUTHOR]

• Synthesis of MIL-100 (Fe) from Fe(OH) 3 slag from hydrometallurgy. • Porous structure improves the rate-multiplying performance of PIBs. • The porous structure improves the K+ migration reaction kinetics. • Incomplete coordination leads to higher carbon content. Recycling spent cathode materials is crucial for sustainably developing lithium-ion battery technology. To achieve the high-value utilization of spent LiFePO 4 (LFP) cathodes, this paper proposes a method for preparing MIL-100(Fe) based on solid waste residues from spent LFP cathodes. R-FeS 2 @C derived from MIL-100(Fe) can serve as an anode material for potassium-ion batteries featuring a porous structure. Electrochemical tests demonstrate that the R-FeS 2 @C exhibits more stable cycling performance compared with the FeS 2 @C derived from the traditional MIL-100(Fe), reaching 525 mAh g−1 after 100 cycles at a current density of 100 mA g−1. Impressively, R-FeS 2 @C also showcases excellent rate performance (343 mAh g−1 specific capacity at 5 A g−1). Furthermore, full cells assembled with PI@rGO cathodes also exhibit excellent rate performance and stable cycling performance. The porous structure of R-FeS 2 @C provides numerous voids to accommodate volume changes and introduces sufficient channels for electrolyte penetration. The higher carbon content enhances the electrical conductivity improving the kinetics of the K+ migration reaction. These researches can provide guidance for the recycling of spent lithium-ion batteries and the design of sulfide electrodes for PIBs. [Display omitted] [ABSTRACT FROM AUTHOR]

• A heterostructure consisting of Co@NC and NiMo-LDH was achieved. • Electron coupling in heterogeneous structures accelerates the electron transport rate. • The DFT results confirm the synergetic effect between the Co@NC and NiMo-LDH. • The assembled Zn-air battery exhibit a high paek density of 210 mW cm-2. It remains an urgent task to design electrocatalysts with fast oxygen evolution reaction (OER) kinetics and enriched active sites for flexible Zn-air batteries. In this paper, a structure engineering strategy is proposed to design an electrocatalyst with a heterostructure comprising Co@NC and NiMo-LDH on carbon cloth, which serves as an air electrode for a quasi-solid-state Zn-air battery. This unique heterostructure significantly enhances electrocatalytic activity, producing low OER overpotentials of 198 mV at 10 mA cm-2. Moreover, the assembled rechargeable Zn-air battery exhibits a high peak density and long cycle stability. Density functional theory calculations indicate that the multimetallic heterostructure induced synergistic and electronic coupling effects among the metal active sites, facilitating rapid ion and electron transport during the OER process. In addition, the migration of oxygen species at the Ni and Mo sites reduces the reaction potential barrier, resulting in a low OER overpotential of 160 mV. The construction of multi-metallic heterostructures enables optimisation of the electronic environment around the active sites and synergistic enhancement of the OER activity, leading to high performance quasi-solid-state Zn-air batteries. [Display omitted] [ABSTRACT FROM AUTHOR]

In this paper, (NH 4) 2 V 4 O 9 nanosheets coexisting with carbon nanotubes were prepared by hydrothermal method as cathode materials for aqueous zinc ions, which can improve the electrochemical performance of the battery. The structure, morphology and electrochemical properties of (NH 4) 2 V 4 O 9 /CNTs were studied and analyzed by physical characterization and electrochemical tests. Carbon nanotubes coexisting with (NH 4) 2 V 4 O 9 provide an electron transfer channel, significantly improving the rate performance of the material. The discharge specific capacity of (NH 4) 2 V 4 O 9 /CNTs is 445 mAh g −1 at a current of 0.1 A g −1; while the discharge specific capacity still remains 207.16 mAh g −1 when the current up to 5.0 A g −1. After 2000 cycles at a high current density of 10 A g −1, the discharge specific capacity of the battery remained 93.1 mAh g −1 from 115.2 mAh g −1 in the first cycle, showing good cycle performance. Therefore, (NH 4) 2 V 4 O 9 /CNTs has fast charge-discharge performance and cycle stability. [ABSTRACT FROM AUTHOR]

Silicon (Si) and silicon monoxide (SiO) have attracted great interest as next-generation anode materials for lithium-ion batteries (LiBs) due to their high energy density. However, their commercialization has been hindered by rapid capacity fading, which stems from mechanical degradation (e.g., cracking and delamination) and the aggressive formation of solid electrolyte interphase (SEI) layer. While understanding these degradation mechanisms in batteries necessitates in-operando measurement techniques, very few non-destructive analytical methods have been documented in literature. This paper highlights the effectiveness of combined electrochemical impedance spectroscopy (EIS) and distribution of relaxation times (DRT) techniques in performing systematic characterization of LiNi 0.6 Mn 0.2 Co 0.2 O 2 (NMC)/nano-Si and NMC/micro-SiO full-cells. The systematic design of experiments enabled the separate deconvolution of anode and cathode aging using symmetrical cells. This approach offered a clear understanding of the overall degradation mechanisms in the full-cells. The major impedance sources in the NMC/nano-Si full-cell were anode contact impedance, resulting from mechanical degradation of Si, and cathode charge transfer impedance, due to significant lithium loss and consequently deeper extraction of lithium ions in NMC. In contrast, micro-SiO anodes exhibited less electrode-level degradation, as evidenced by SEM images and relatively stable impedance behaviors during extended cycling, which strongly corroborate its superior capacity retention (66 % at 300th cycle) compared to that of nano-Si anode in full-cells (26.5 % at 300th cycle). [ABSTRACT FROM AUTHOR]

• The corrosion of multiphase al-zr-fe alloys containing intermetallics was studied in aqueous solutions of 3.5 % NaCl, H 3 BO 3 and 3.5 % nacl + H 3 BO 3. • 8-week immersion corrosion tests in 3.5 % nacl at 40 °C confirmed different corrosion mechanisms between Al 71 Zr 24 Fe 5 and Al 65 Zr 20 Fe 15 alloys. • High volta potential differences between al-zr and al-fe-zr phases were registered using SKPFM. • The Al 65 Zr 20 Fe 15 alloy was characterized by greater wear resistance in dry conditions and corrosive solutions. • Severe delamination and brittle fracture mechanism was identified for the Al 71 Zr 24 Fe 5 alloy after tribological tests. In this study, the structure of Al 65 Zr 20 Fe 15 and Al 71 Zr 24 Fe 5 alloys was studied using neutron diffraction and SEM with EDX maps. This paper presents the electrochemical measurement results performed in 3.5 % NaCl, H 3 BO 3 , and 3.5 % NaCl+H 3 BO 3 solutions at 40 °C. The Al 71 Zr 24 Fe 5 alloy showed higher corrosion resistance in acidic solution, whereas the Al 65 Zr 20 Fe 15 alloy was more resistant in 3.5 % NaCl+H 3 BO 3. Moreover, the corrosion behavior was described for the samples immersed for 8 weeks in 3.5 % NaCl at 40 °C. SKPFM indicated high Volta potential differences between Al-Zr and Al-Fe-Zr phases. Moreover, the higher wear resistance for Al 65 Zr 20 Fe 15 compared to the Al 71 Zr 24 Fe 5 alloy was demonstrated. [ABSTRACT FROM AUTHOR]

In this paper, the effects of chloride ions, oxygen, and carbon dioxide on the corrosion resistance of passive films formed on 316 L stainless steel were investigated in the aggressive oilfield environment using electrochemical testing and microscopic characterization techniques. The results showed that Cl− accelerated the anodic dissolution of the metal and compromised the structure and densification of the passive film, thus reducing its corrosion resistance. An increase in the partial pressure of carbon dioxide initially promotes pitting, but subsequently inhibited further corrosion development. The presence of oxygen enhanced the cathodic reaction and passive film formation, effectively preventing the invasion of aggressive chloride ions, thus inhibiting further corrosion. These findings provide a significant scientific basis for material selection and protection of oil extraction equipment in oilfield environments. [ABSTRACT FROM AUTHOR]

• [Mn(H 2 O) 6 ]2+ can accumulate in oriented sulfonate-functionalized silica thin films. • Their reaction with Na 2 WO 4 ●2H 2 O enables in situ' synthesis of a polyoxometalate. • The immobilized [Mn(H 2 O) 3) 2 (H 2 W 12 O 42)] n 6n- polyoxometalate is electroactive. • [Mn(H 2 O) 3) 2 (H 2 W 12 O 42)] n 6n- in silica exhibits good voltammetric operational stability. We present in this paper the 'in situ' preparation of manganese-containing polyoxotungstate [Mn(H 2 O) 3) 2 (H 2 W 12 O 42)] n 6n- (1) chains in vertically-oriented mesoporous silica thin films on indium-tin oxide (ITO) electrodes. Taking advantage of a soft sequential method allowing the formation of 1 inside the mesoporous matrix, we succeed in its 'in situ' formation according to two main steps: (i) a first one consisting of the immobilization of [Mn(H 2 O) 6 ]2+ in sulfonate-functionalized silica thin films; and (ii) a second one involving the reaction of the [Mn(H 2 O) 6 ]2+ moieties with Na 2 WO 4 2H 2 O. The electrochemical characterization of the functionalized materials obtained clearly demonstrates that the content of sulfonate groups in the starting films is a critical parameter to get the expected electroactive [Mn(H 2 O) 3) 2 (H 2 W 12 O 42)] n 6n- compound inside the silica nanochannels. The experimentally determined chemical composition of the films performed by X-ray Photoelectron spectroscopy (XPS) is in good agreement with the expected composition of 1 in the case of films obtained with the optimal content of sulfonate functions (i.e. , 5–6.5 % sulfonate with respect to silica). Energy Dispersive analysis of X-rays coupled with Transmission Electron Microscopy (TEM-EDX) carried out on the cross section of the films show that a uniform composition in terms of Mn/W ratio is obtained after the functionalization process. This confirms the formation of [Mn(H 2 O) 3) 2 (H 2 W 12 O 42)] n 6n- uniformly within the whole thickness of the silica film (i.e. , 80 nm), explaining also the long-range charge transfer reactions occurring through such insulating silica membrane. Using sulfonated silica films as template, we develop a robust 'in situ' synthesis strategy to assemble 1D linear polyoxotungstates onto ITO electrodes, exhibiting a stable electrochemical response once confined within the silica nanochannels. [ABSTRACT FROM AUTHOR]

• The current density is 10 mA cm-2 at 1.0 M KOH, the HER and OER showed an underpotential of 159.6 mV and 320.8 mV. • The catalyst was assembled as anode and cathode form a double electrode, and the overall water splitting and urea decomposition voltages were 1.65 V and 1.63 V. • Au 2 /CeO 2 ‖Au 2 /CeO 2 showed no significant change in 10 mA cm-2 for 100 h continuous stability test. The development of exceptionally active and stable trifunctional electrocatalysts is essential to facilitate industrial applications of proton exchange membrane electrolyzers. Rare earth catalysts have a wide range of applications in alkaline solution oxidation, but limitations in their stability and activity prevent their further application. In this paper, Au doped CeO 2 coated porous Au x /CeO 2 (x = 1,2,3) was designed as a three-function electrocatalyst with excellent performance and stability. At 1 M KOH conditions, both the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER) reactions exhibit excess potentials of 159.6 and 320.8 mV at a current density of 10 mA cm-2. In addition, when incorporated into an Au 2 /CeO 2 (0.05 mmol, HAuCl 4 ·4H 2 O) microparticles, the catalyst exhibits the potential of 1.42 V(10 mA cm-2) containing 0.33 M urea in 1 M KOH. Remarkably, for hydrogen production driven by urea electrolysis, Au 2 /CeO 2 demonstrated exceptional performance by requiring only a voltage input of 1.63 V. The reducing agent that forms the Au/CeO 2 heterojunction modulates the electronic structure of the Au active site and optimizes the adsorption of the intermediate. In addition, the interaction of the Au monolayer with the CeO 2 nanosphere effectively prevents excessive oxidation and dissolution of Au, and the porous hollow structure provides additional exposed active sites and facilitates mass transfer. [Display omitted] [ABSTRACT FROM AUTHOR]

• Faradaic efficiency calculations to diversify between two and four-electron water oxidation. • Molybdenum (VI) oxide as a promising catalyst towards two-electron water oxidation. • In-situ tracking of wastewater analogue (methylene blue) concentration during electrolysis process. The measurements of gas volumes evolved during electrochemical wastewater treatment provide the information on the process faradaic efficiency. This work demonstrates how it enables identification of the water oxidation pathway (2 or 4 electron) in flow electrolysis process through the application of the formulae suggested in the study. This way, the real wastewater oxidation strength, i.e. production of hydrogen peroxide can be determined based on calculations. These provide more accurate results than direct measurements of accumulated hydrogen peroxide concentration after the electrolysis process, as its instability may lead to its immediate decomposition and false results. As an example provided in the paper, the application of MoO 3 as a catalyst in the carbon composite electrode indicates almost no hydrogen peroxide detected after the process, whereas its oxidative properties owing to production of hydroxyradicals demonstrate complete decomposition of wastewater analogue (methylene blue). The calculations point to high production of H 2 O 2. Using pure carbon material without the catalyst in the same experiment, decomposition occurs at much lower rate. The possible mechanisms behind the processes are discussed. The approach presented in the work can aid to efficient development of catalysts towards two-electron water oxidation. [Display omitted] [ABSTRACT FROM AUTHOR]

Ferrocenyl aniline is an excellent catalyst used conventionally for heterocyclic syntheses. The use of ferrocenyl aniline, in the presence of electropolymerized thiophene-3-acetic acid (TAA) on carbon fibre paper is novel and found to be an exceptional electrocatalyst, for the synthesis of a proven anti-fungal, anti-proliferative and anti-bacterial, 2-(4-methoxyphenyl)-1 H -benzo[ d ]imidazole. The electrode performance was examined with activity studies and EIS, along with surface characterizations including optical profilometry, FE-SEM, FT-IR and XPS. The synthesis was performed in a single-cell three electrode system, using platinum as counter and saturated calomel electrode (SCE) as the reference, with ethanol as the electrolyte and lithium perchlorate supporting electrolyte. The reaction was performed with o- phenylenediamine and anisaldehyde as starting materials at ambient temperature and pressure, at 1.35 V constant potential for 3 h, and product was isolated and purified using column chromatography to obtain 91% yield and characterized with GC–MS and NMR. This synthesis method is noteworthy, due to its environmentally friendly performance, and high yield for a benzimidazole derivative that is pharmacologically vital. [ABSTRACT FROM AUTHOR]

• A robust electrocatalyst ZnO-POPD-GCN-TCFP electrode was developed. • The electrochemical oxidation of furfuryl alcohol was successfully carried out at the developed electrode under benign reaction conditions. • An affordable, sustainable, and environmentally friendly approach for synthesizing furfural was designed. In this work, Poly(o-phenylenediamine) (POPD) and zinc oxide (ZnO) nanoparticles were electrochemically deposited on GCN (graphitic carbon nitride) coated TCFP (Toray carbon fiber paper) electrode. The modified electrode ZnO-POPD-GCN-TCFP was assessed by Field emission scanning electron microscopy (FESEM), X-ray diffraction analysis (XRD), and X-ray photoelectron spectroscopy (XPS) studies. The electrochemical studies were carried out via cyclic voltammetry (CV) and electrochemical impedance spectroscopic (EIS) methods. The developed electrode was employed for the oxidation of furfuryl alcohol (FA) using 4-ACT (4-acetamido TEMPO) as a mediator in an alkaline medium via bulk electrolysis. Proton nuclear magnetic resonance (1H NMR) spectroscopy was used to characterize the final product. The oxidation of FA to furfural was accelerated by the heterogeneous catalyst ZnO-POPD-GCN-TCFP electrode owing to its good electrocatalytic activity and stability. Hence, a sustainable electrochemical method for synthesizing furfural, with significance in the realm of green chemistry, was developed. The Electro-oxidation of FA offers a clean alternative to traditional methods utilizing electricity, potentially from renewable sources, to drive the reaction, reducing reliance on harsh chemicals and minimizing environmental impact. By adjusting parameters like electrode potential and electrolyte composition, it is possible to optimize the reaction conditions for furfural production with optimal yield, which has several applications in daily life. [Display omitted] [ABSTRACT FROM AUTHOR]

Electrokinetic energy conversion (EEC) offers a promising avenue for transforming elusive natural energy into electric power, showing a wide application spectrum. Unlike prevalent studies that chiefly utilize symmetrical electrolyte solution (e.g., KCl) and uniformly structured negatively charged nanochannels for EEC, this paper delves into a thorough examination of EEC characteristics—streaming current, streaming potential, and output power—in both positively and negatively charged conical nanochannels with symmetrical and asymmetric (CaCl 2 and LaCl 3) electrolytes solutions. Operating under the assumption that the electrolyte solutions (KCl, CaCl 2 , and LaCl 3) possess equivalent ionic strength and, thereby, a common Debye length, our findings reveal a significant dependency of EEC characteristics and their regulation parameters on the electrolyte type, nanochannel charge polarity, and ionic strength. As the ionic strength increases, both the streaming current and output power initially rise to a peak before subsequently declining, with the ionic strength at the peak being influenced by the cation valence: lower valence leads to lower ionic strength. In asymmetric electrolyte scenarios, optimal EEC characteristic is observed in positively charged conical nanochannels under a reverse pressure difference, attributed to the ion-selective and ionic concentration distribution in the charged conical nanochannels. Moreover, the complex behaviors of the regulation parameters of EEC characteristics are unveiled. Notably, a tri-valent electrolyte's regulation parameters exceed those of a bi-valent electrolyte, indicating that ionic valence asymmetry enhances the regulation effects on EEC in conical nanochannels. [ABSTRACT FROM AUTHOR]

Hematite (α-Fe 2 O 3) is considered a promising electrode material due to its cost-effectiveness and high theoretical specific capacity. In this paper, we prepared Fe 2 O 3 nanoparticles by hydrothermal method. To improve the drawbacks such as poor conductivity and low practical capacity, NiCo 2 O 4 nanorods and graphene oxide (rGO) are added to Fe 2 O 3 nanoparticles. The composite exhibits a specific capacity of 644 F g−1 at a current density of 1 A g−1. The higher ion diffusion rate can improve the specific capacity and energy density in optimized composites. At a current density of 1 A g−1, compared to Fe 2 O 3 , the specific capacity and energy density of Fe 2 O 3 /NiCo 2 O 4 /rGO were increased by 278.8 % and 304.5 %, respectively. In order to stimulate more potential applications, we encapsulated Fe 2 O 3 /NiCo 2 O 4 /rGO-//Co 3 O 4 asymmetric supercapacitors with binder-free Co 3 O 4 as the counter electrode. Determining the optimal positive and negative active substance mass ratio by controlling the amount of charge, the device can deliver a high specific capacity of 280.6 F g−1 at a current density of 1 A g−1 and power density of 354.8 W Kg−1 while providing a high energy density of 56.1 Wh Kg−1. These results indicate that Fe 2 O 3 /NiCo 2 O 4 /rGO has potential for electrochemical energy storage, which could provide new ideas for new commercial supercapacitors. [ABSTRACT FROM AUTHOR]

Mn 0.5 Ti 2 (PO 4) 3 with a NASICON structural is used as an anode material in potassium-ion batteries due to its abundance of vacancies that can hold potassium ions. This characteristic not only contributes to its excellent stability but also results in a high specific capacity. However, the poor electrical conductivity of the polyanionic type structure limits the material's ability to fully utilize its capacity. In this paper, the conductivity and electrochemical stability of the Mn 0.5 Ti 2 (PO 4) 3 anode material are enhanced through composite formation with an F-doped carbon layer. The introduction of F into the carbon matrix creates a large number of vacancy defects and F active sites. The vacancies enhance the transport of potassium ions on the Mn 0.5 Ti 2 (PO 4) 3 material's surface, while the active sites exhibit strong electronegativity, improving the absorption of potassium ions. Therefore, the diffusion impedance of potassium ions is significantly reduced, leading to an increased diffusion rate of potassium ions. Attributing to the improved reaction kinetics, the Mn 0.5 Ti 2 (PO 4) 3 @F-doped carbon composite demonstrates a high specific capacity of 86 mA h g−1 at 10,000 mA g−1 when used as the anode for potassium-ion batteries. Even more, the specific capacity remains a capacity of 136 mA g−1 after 3000 cycles at 1000 mA h g−1. This study enhances our comprehension of material design by investigating the alteration of carbon matrix to promote the electrochemical characteristics of materials. [ABSTRACT FROM AUTHOR]

• A hand-torn bread-like 3D porous structure anode was firstly proposed in MFCs. • A new mode of accelerating electronic transfer was explored. • PANI-PPy-Ag NWs/CF hydrogel anodes are hydrophilic and biocompatible. • It has high COD removal rate (96.69 %) and power density output (2196.61 mW/m3). • The two direct electron transfer pathways were achieved simultaneously. Microbial fuel cell (MFC) can generate electrons through microbial metabolism of organic matter in sewage. In this paper, carbon felt as base material, the conductive polymers polyaniline and polypyrrole combined with silver nanowires were doped in hydrogel, a super hydrophilicity, low electron transfer resistance, good biocompatibility hydrogel MFC anode (PANI-PPy-Ag NWs/CF) were prepared. It showed a hand-torn bread structure, this three-dimensional (3D) porous structure increased microbial attachment amount. The anode could reach a maximum voltage output of 0.66 V in only 5.5 h, and produce a maximum power density of 2196.61 mW/m3. Due to the doping of silver nanowire, a new electronic mode was explored, coulomb efficiency of 31.01 % and an ultra-high COD removal rate (96.69 %) was obtained. This study introduces a conductive composite hydrogel MFC anode, which provides a new idea for the material diversity, electrical production and sewage removal performance of MFC anode. [ABSTRACT FROM AUTHOR]

This paper introduces the combination of an advanced double-layer model with electrochemical kinetics to explain electrolyte effects on the alkaline hydrogen evolution reaction. It is known from experimental studies that the alkaline hydrogen evolution current shows a strong dependence on the concentration and identity of cations in the electrolyte, but is independent of pH. To explain these effects, we formulate the faradaic current in terms of the electric potential in the double layer, which is calculated using a mean-field model that takes into account the cation and anion sizes as well as the electric dipole moment of water molecules. We propose that the Volmer step consists of two activated processes: a water reduction sub-step, and a sub-step in which OH − is transferred away from the reaction plane through the double layer. Either of these sub-steps may limit the rate. The proposed models for these sub-steps qualitatively explain experimental observations, including cation effects, pH-independence, and the trend reversal between gold and platinum electrodes. We also assess the quantitative accuracy of the water-reduction-limited current model; we suggest that the predicted functional relationship is valid as long as the hydrogen bonding structure of water near the electrode is sufficiently maintained. [ABSTRACT FROM AUTHOR]

• Multi-step electrodeposition significantly reduces total electrodeposition time and facilitates large-scale production of high-performance electrodes. • Multi-step electrodeposited layers are more uniform, the deposition mass is controllable, reaching 12–13 mg. • A high areal capacitance of 7881 mF cm-2 was achieved for the NiCo-LDH electrode by multi-step electrodeposition. In comparison with single-step electrodeposition, multi-step electrodeposition for electrode preparation is more effective in releasing internal stresses, utilizing the highly efficient deposition time at the beginning of the electrodeposition, improving deposition efficiency, and producing adhesive-free high-performance electrodes with controllable mass. In this paper, NiCo layered double hydroxide (NiCo-LDH) with similar mass was successfully deposited by a two-electrode constant-current electrodeposition method using nickel foam as the substrate through different electrodeposition steps. A comparative study was conducted on the effects of NiCo-LDH deposition steps on the morphology, total deposition time, and electrochemical performance of NiCo-LDH samples. The results show that the mass of NiCo-LDH grown on foam nickel is similar when the number of deposition steps is from 1 to 6 at 12–13 mg, the coating of foam nickel substrate became more uniform. The total deposition time has decreased from 2550 s for 1-step deposition to 1542 s for 6-step deposition, reducing the occupation time of the electrodeposition equipment. As the number of deposition layers increases, the specific capacitance of NiCo-LDH shows a trend of first increasing and then stabilizing. The high mass specific capacitance of NiCo-LDH electrode material deposited in 6 steps is 953 F g −1 at a current density of 3 mA cm−2. The assembled asymmetric supercapacitor device achieved an energy density of 0.309 mWh cm−2 at a power density of 4.25 mW cm−2, and a capacitance retention rate of 94% after 10,000 cycles at a current density of 40 mA cm−2. This indicates that the NiCo-LDH material prepared by multi-step electrodeposition method has good capacitance performance, providing a simple and time-saving method for manufacturing large-scale multi-step electrodeposition of adhesive-free supercapacitor electrodes. [ABSTRACT FROM AUTHOR]

Symmetrical solid oxide fuel cells (SSOFCs) use the same materials as electrode, thereby reducing fabrication processes, simplifying interface problem and improving tolerance to coking and sulfur. In this paper, the multifunctional Sr 2 Ti 0.8 Ni 0.2 FeO 6– δ (STN02F) oxide is successfully synthesized and evaluated to be as symmetrical electrodes for SOFCs. The Ni-Fe alloy nanoparticles can be exsolved from STN02F sample in high temperature reducing atmosphere. The impedance stability test demonstrates that the polarization resistance (R p) of STN02F exhibited no obvious change in both air and H 2. The fuel cells obtain the maximum power densities of 710 mW cm–2 in H 2 , 581 mW cm–2 in CH 3 OH, 527 mW cm–2 in C 3 H 8 and 213 mW cm–2 in direct C at 800 °C. The fuel cell exhibited no output performance degradation during the 200 h test in H 2. The current densities of 0.84 A cm−2 at 1.3 V in 50%H 2 O/50%H 2 and 0.77 A cm−2 at 1.5 V in CO 2 were obtained for electrolysis cell at 800 °C. The efficient and stable symmetrical electrode STN02F is a promising candidate material for SOCs. [Display omitted] [ABSTRACT FROM AUTHOR]

• The effect of the concentration boundary layer thickness on the MMFC performance is investigated. • The proposed modification enhances mass transport as it thins the concentration boundary layer. • The limiting current density increases by 91.5 % as the concentration overpotentials are reduced. • The oxidant concentration on the electrode surface is increased from 0.055 mol/m3 to 0.19 mol/m3. The concentration boundary layer thickness is one of the most important parameters used to characterize the performance of membraneless microfluidic fuel cells. Low concentration boundary layer thickness leads to a high electrochemical reaction over the electrodes, improving the performance of the fuel cell. For this purpose, this paper proposes a modified microchannel which directs the fuel and the oxidant to the electrode surfaces. According to the results obtained, the amount of concentration on the cathode electrode surface and therefore the amount of current density increased with the modified microchannel. At the same point of the cathode electrode surface, the oxidant concentration in the conventional microchannel was 0.055 mol/m3, while it was 0.19 mol/m3 in the modified microchannel. Since the concentration overpotential reduced, the limiting current density was 0.372 mA/cm2 in the conventional microchannel and 0.741 mA/cm2 in the modified microchannel. Thus, the limiting current density value increased by 91.5 %. [ABSTRACT FROM AUTHOR]

• Variations of battery expansion force during charge and discharge are quantified. • Variation patterns of expansion force during thermal runaway are compared. • Time series of expansion force versus T, V during thermal runaway are compared. • Feasibility of expansion force and its growth rate as warning signals are verified. In recent years, lithium-ion batteries have been widely adopted by the automotive industry because of their high energy density and environmentally friendly nature. However, the thermal runaway of lithium-ion batteries poses a significant risk of explosions, fires, and other hazards. Therefore, it is crucial to have effective thermal runaway warning systems to enhance the safety of battery applications. Currently, the main warning signals for thermal runaway include voltage, temperature, internal resistance, gas composition, and smoke. However, these signals suffer from issues such as low accuracy and delayed warnings. During thermal runaway, voltage, temperature, internal resistance, expansion force, and smoke undergo abnormal changes at varying times, with expansion force abnormalities detected notably earlier. To improve the accuracy and timeliness of thermal runaway warnings, it is crucial to quantitatively measure the changes in expansion force and signal progression related to voltage and temperature during thermal runaway through experiments. In this study, the 51 Ah LiNi 0.5 Co 0.2 Mn 0.3 O 2 /Graphite commercialized Li-ion batteries were used to study the characteristics of thermal runaway expansion force at different states of charge (SOCs) (25%, 50%, 100%, 110%). The variation patterns of thermal runaway parameters such as temperature, voltage, internal resistance, expansion force, and flame were analyzed. The test results indicate that the expansion force in lithium-ion batteries is related to the lithium-ion concentration in the negative electrode and remains below 2000 N with a rate of change under 1.8 N/s during normal charging and discharging. However, it surpasses 5000 N for thermal runaway. This paper suggests using a 2000 N expansion force as an early warning signal for thermal runaway, which precedes approximately 11.6 s earlier than the voltage signal and 10 s earlier than the internal resistance and temperature signals. Adopting a 1.8 N/s growth rate can further enhance warning time, issuing alerts 134.2 s before thermal runaway. Research confirms that using expansion force as the main signal significantly improves warning time and alarm accuracy in lithium-ion battery safety. [ABSTRACT FROM AUTHOR]

Electrochemical ammonia production from molecular nitrogen and nitrate reduction reactions at ambient conditions has gained a lot of attention in recent years, making this topic more and more appealing. The race towards good and quick results in terms of Faradaic efficiency and productivity is not always focused on the possible source of ammonia contamination. In particular, Nafion membrane is the most commonly used in this field as cell separator, discarding the possible known disadvantages coming from ammonium ions absorption and release. The wettable microporous Celgard membrane has been proposed as a substitute for Nafion membranes, despite the separation mechanism, in this case, is only dimension-driven, so it does not assure ammonium ions retention. This paper reveals that the mechanism of ammonium ions absorption and release by Nafion 117 is strongly related to the cations present in the electrolyte and to a lesser extent by its pH value. On the other hand, Celgard membrane does not show any relevant ammonium ions absorption. Moreover, the different trend of ammonium ions motion from catholyte to anolyte solution inside a flow-cell reactor shows that none of the membranes is able to avoid ammonium ions crossover and that there is a correlation between the applied potential and the motion trend. Electrochemical nitrogen and nitrate reduction tests confirm how Nafion membrane can have a big impact on the final result of ammonium ions production, especially when dealing with low production quantities, leading to mistakes in the real quantity of ammonium ions coming from the reduction reaction. [ABSTRACT FROM AUTHOR]

• The evolution of EIS of zinc-rich coatings is explained in detail. • The corrosion product layer causes the shielding effect of zinc-rich coatings. • Semi-logarithmic relationships suggest that t1/2 axis is useful for impedance studies. • Linear correlations help in designing equivalent circuits (EE). • Linear correlations help in elucidating the physical meaning of EE components. This paper focuses on elucidating the variation rules of equivalent circuit elements of electrochemical impedance spectra (EIS) of two different thicknesses of epoxy zinc-rich coatings (EZRCs) and silicate ethyl zinc-rich coatings (ZRCs). The correlation between the circuit elements and the low-frequency impedance modulus (|Z| 0.01 Hz) and the open-circuit potential (OCP) is investigated, and an explanation of the barrier effect and the evolution law of corrosion potential (E corr) is given. The results show that there is a linear or piecewise linear relationship between the logarithm of |Z| 0.01 Hz and the circuit elements with a square root of time (t1/2), and the piecewise linear relationship between the OCP and t1/2. Further, there is a large amount of linear correlation between circuit elements. The semi-logarithmic linear relationship suggests that the square root axis can be a conventional choice for coating impedance studies. Linear correlations help in designing equivalent circuits and elucidating the physical significance of components in equivalent circuits. The barrier effect of ZRCs mainly refers to the blocking effect of the corrosion product layer on the outer surface of the coating. The barrier effect of ZRCs can be neglected. Designing equivalent circuits: location of circuit elements and current assignments, fitting accuracy, trends in model parameters, linear correlation of elements. [Display omitted] [ABSTRACT FROM AUTHOR]

Graphitic carbon nitride (g-C 3 N 4) is characterized by easy synthesis, high porosity and high nitrogen doping level. It has good application prospects as an negative electrode material for metal-ion batteries. However, graphitic carbon nitride (g-C 3 N 4) cannot be directly used as negative electrode material (NEMs) for lithium-ion batteries due to poor electrical conductivity and poor cycling performance. To solve this problem, in this paper, g-C 3 N 4 is synthesized on the surface of reduced graphene oxide by in situ synthesis method. The prepared rGO-g-C 3 N 4 composites have high surface capacitance process occupancy due to the presence of a large amount of pyridinic-N and pyrrolic-N, and various defects and pores generated during the synthesis process provide a large lithium-ion mobility rate for the rGO-g-C 3 N 4 composites. The rGO-g-C 3 N 4 composites have excellent electrochemical properties and excellent lithium storage performance, the capacity of 1 A/g after cycling 300 laps to maintain a high lithium storage capacity of 708.6 mAh/g, and is still in the rising state, even if the current density of 15 A/g under the cycle of 10,000 laps, the highest lithium storage capacity of up to can still be up to 423.6 mAh/g, and stabilized in the 306.8 mAh/g. This work provides a new idea for the preparation of new negative electrode materials with low cost and high capacity. [ABSTRACT FROM AUTHOR]

Impedance spectroscopy is nowadays in use in a wide range of applications where there is a particular need for efficient embedded measurement systems. Several embedded impedance spectrometers based on Field Programmable Gate Array (FPGA) have been proposed but have several drawbacks, notably high power consumption, high cost, and complex development frameworks. Meanwhile, microcontrollers have become more powerful, enabling the efficient design of embedded impedance spectrometers. A major challenge, however, is to achieve high measurement performance in terms of accuracy while complying with the conditions for impedance spectroscopy. This paper addresses the potential of microcontroller-based system design for embedded impedance spectrometers and proposes a methodology to comprehensively design compact and efficient microcontroller-based impedance measurement systems. After a review of possible measurement methods, we focus on the optimization of multi-sine excitation signals,the acquisition of current and voltage signals, and the efficient signal analysis, which are key elements in realizing embedded impedance measurement systems that achieve high quality measurements while maintaining linearity and system stability conditions. We demonstrate the efficiency of the proposed design methodology in the two application scenarios of battery diagnosis and bioimpedance spectroscopy. • Critical aspects in designing impedance spectrometer systems with limited resources. • Methodology for efficient embedded impedance measurement based on microcontrollers • Dedicated excitation signals and signal processing techniques for implementation on microcontrollers • Optimization of multisine excitation signals for maintaining linearity and stability conditions • Demonstration of the proposed methodology in battery impedance spectroscopy and bioimpedance spectroscopy. [ABSTRACT FROM AUTHOR]

Co-Ni bi-metallic thin films with different stoichiometries have been deposited by magnetron co-sputtering technique on Ni foam (NF), Si and carbon paper substrates. The structural and morphological characterisations of these films have been done by X-ray diffraction, X-ray absorption spectroscopy and Field Emission Scanning Electron Microscope measurements. The performances of these films for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) have been evaluated through electrochemical measurements like Linear Sweep Voltammetry, Cyclic Voltammetry and Electrochemical Impedance Spectroscopy measurements. Operando X ray absorption near edge spectroscopy measurements have also been carried out during HER and OER to decipher the redox reaction mechanisms. It has been observed that the HER and OER performance of all the Co Ni bi-metallic thin films on NF are found to be better than that of bare NF. The CoNi sample with composition of 58.7 % Co and 41.3 % Ni shows the best catalytic activity and stability towards HER and OER reactions. Though the HER activity is not the best but is comparable to many results reported in the literature, however the catalyst shows excellent OER activity with overpotential of 214 mV for 10 mA/cm2 current density. This is much better than that of the OER benchmark catalyst RuO 2 and most of those reported in the literature. The OER is kinetically slower than HER and requires more overpotential, hence a significant improvement in the catalytic OER activity will definitely enhance the overall water splitting activity and hydrogen production efficiency. Thus the Co-Ni bi-metallic catalyst prepared by an easily scalable and highly reproducible magnetron co-sputtering technique has significant potential to emerge out as a technologically viable water splitting catalyst. [ABSTRACT FROM AUTHOR]

Anodic aluminum oxides (AAO) with attractive morphological properties might be obtained by pulse anodizing via controlled hydrogen release during the cathodic step. In order to enhance such processes currently relying on empirical studies, the present paper aims to investigate basically the AAO formation on pure aluminum in sulfuric acid during a bipolar pulse anodizing process, by combining in situ electrochemical measurements and cross-section scanning electron microscopy. Results show that the hydrogen evolution at the metal/oxide interface during the cathodic step can be easily managed by current control. Actually, under cathodic galvanostatic conditions, successive mechanisms occur, depending on both the duration and the current density: a first stage corresponds to the reorganization of the electric charges and the migration of H + through the AAO barrier layer and is followed by hydrogen evolution at the metal/oxide interface, which induces the formation of local or more extended defects at the metal/oxide interface until the detachment of the AAO layer. [ABSTRACT FROM AUTHOR]

• A PEO/MgAlLa LDHs-MXene@A composite coating was prepared on LPSO Mg-Gd-Y-Zn alloy. • Aminosilane promoted the compounding of MXene sheets with 4-aminophenol corrosion inhibitor. • The structure of LDHs was optimized by MXene@4-Aminophenol and can carry more corrosion inhibitor. • The P/MgAlLa LDHs-M@A coating had excellent corrosion resistance and self-healing properties. • The self-healing mechanism and process of the P/MgAlLa LDHs-M@A coating were elucidated. This paper provides an effective method to solve the problems that magnesium alloys easily corrode and their coatings are easily damaged. The micro-pores of PEO coating on the Mg alloy were sealed by in-situ growth of MgAlLa LDHs, and then compounded with MXene doped 4-aminophenol corrosion inhibitor to obtain PEO/MgAlLa LDHs-MXene@4-Aminophenol (P/MgAlLa LDHs-M@A) composite coating. The structure, morphology and composition of the P/MgAlLa LDHs-M@A coating contained the successful combination of MgAlLa LDHs and MXene@4-Aminophenol. The P/MgAlLa LDHs-M@A coating had excellent corrosion resistance and self-healing properties, with an impedance modulus | Z | 0.01 of 8.8 × 107 Ω cm2. Scratch defects were self-healed within 12 h. In addition, the mechanisms of corrosion resistance and self-healing were explained. [Display omitted] [ABSTRACT FROM AUTHOR]

Multiple drug concentrations concurrent detection and quantification based on electrochemical sensors are of great importance for therapeutic drug monitoring (TDM) and the development of personalized therapy. Cyclic voltammogram (CV) results obtained by electrochemical sensors can be used to offer quantitative information about drug concentrations. Several approaches have been proposed for single-concentration quantification based on CV results and machine learning (ML) models with lower training difficulty. However, insufficient measured dataset hinders the application of diverse large-scale ML algorithms in this field. A new method for automatic parameter estimation by ML of measured CV samples is here illustrated with the aim to generate a large simulated dataset for generalized drug concentration quantification model training in this paper. We present an ML-based approach that combines k-means clustering, polynomial regression, and Gaussian Mixture Model (GMM), which automates parameter estimation and simulation using peak detection, baseline subtraction, and peak Gaussian fitting with a small number of measurements. Large simulation datasets constructed on the basis of the estimation results open the possibility of training ML models for more generalized drug concentration quantification. The simulated dataset is processed to assess the efficiency of the proposed method. The Mean Average Percentage Error (MAPE) was 0.32% for etoposide (ETO) and 4.78% for methotrexate (MTX). • Automatic parameter estimation of measured cyclic voltammogram samples by machine learning. • Integration of machine learning algorithms for peak detection, baseline subtraction, and peak Gaussian fitting. • Large simulated dataset generation to achieve generalized drugs quantification model training. [ABSTRACT FROM AUTHOR]

• Oxygen vacancies were introduced by NaOH etching. • Oxygen vacancies increase active site and promote charge transfer. • The NH 3 yield and FE of the catalyst reach 13.18 μg h −1 mg−1and 16.51%. Electrocatalytic nitrogen reduction reaction (NRR) is a green and environmentally friendly ammonia production method, which is expected to replace the conventional Haber-Bosch process. In this paper, a Bi 2 MoO 6 electrocatalyst with abundant oxygen vacancies was obtained by solvothermal method and sodium hydroxide etching treatment. The introduction of oxygen vacancies increased the active site of the catalyst and promoted the charge transfer and N 2 adsorption, which finally significantly increased the activity of the catalyst. In 0.1 M Na 2 SO 4 solution at a potential of -0.2 V (vs. RHE), the Bi 2 MoO 6 with oxygen vacancies obtained an excellent Faradaic efficiency of 16.51% and an NH 3 yield of 13.18 μg h −1 mg−1, which is about 4 times that of bare Bi 2 MoO 6. This study provides a new idea to improve the activity of the catalyst for NRR. Schematic diagram of electrochemical N 2 reduction. [Display omitted] [ABSTRACT FROM AUTHOR]

Lithium (Li) metal has been widely regarded as the optimal anode material for the high-energy density rechargeable batteries, due to its ultrahigh theoretical specific capacity and lowest electrochemical potential. However, the formation of Li dendrites presents a significant safety concern, which limits its practical application. In this paper, to address this issue, an efficient and cost-effective strategy was proposed to prepare a zinc-copper composite collector (ZCC) with outstanding electrochemical performance, which can effectively suppress the formation of lithium dendrites. The lithophilic surface with ZnCu alloy nanoparticles was achieved through physical vapor deposition followed by annealing treatment. The ZCC collector enables dendrite-free deposition of Li due to its negligible nucleation overpotential. Even at high area capacity of 3 mAh cm−2 at 1 mA cm−2 in half-cells, the ZCC exhibits exceptional cycling performance and high coulomb efficiency. Preloaded with Li, the composite electrode (Li/ZCC) delivers an enhanced lifespan with low overpotential evidently. Matched with LiFePO 4 (LFP) cathode, LFP||Li/ZCC full cells reveal a superior cycling stability with enhanced capacity retention of 85 % (after 1000 cycles at 1 C) and 87 % (after 800 cycles at 3 C) respectively. [ABSTRACT FROM AUTHOR]