Thickness Of Electrolyte Layer Research Articles

A Rotating Cathode with Periodical Changes in Electrolyte Layer Thickness for High-Rate Li‒O2 Batteries.

Li-O2 batteries (LOBs) possess the highest theoretical gravimetric energy density among all types of secondary batteries, but they are still far from practical applications. The poor rate performance resulting from the slow mass transfer is one of the primary obstacles in LOBs. To solve this issue, a rotating cathode with periodic changes in the electrolyte layer thickness is designed, decoupling the maximum transfer rate of Li+ and O2. During rotation, the thinner electrolyte layer on the cathode facilitates the O2 transfer, and the thicker electrolyte layer enhances the Li+ transfer. As a result, the rotating cathode enables the LOBs to undergo 58 cycles at 2.5mA cm-2 and discharge stably even at a high current density of 7.5 mA cm-2. Besides, it also makes the batteries exhibit a large discharge capacity of 6.8 mAh cm-2, and the capacity decay is much slower with increasing current density. Notably, this rotating electrode holds great promise for utilization in other electrochemical cells involving gas-liquid-solid triple-phase interfaces, suggesting a viable approach to enhance the mass transfer in such systems.

Mns-MWCNT Composite, as a Superior Electrode Material for Asymmetric Flexible Quasi Solid-State Supercapacitors

Nowadays, renewable and sustainable energy sources are being explored and promoted to curb global pollution and to solve the issue of depleting fossil fuel resources. However, these renewable energy sources are intermittent in supply, therefore, it becomes necessary to store them for future usage. The traditional storage devices for electrical energy storage are different kinds of batteries but the sluggish performance of batteries, use of toxic heavy metals, issues pertaining to safety and low cycling efficiency are some of its major drawbacks. Recent proliferation of portable, wearable and flexible electronics and adoption of electric vehicles have forced the scientists to look for fast charging, light weight, leak proof, safe, toxic material free, durable energy storage devices like supercapacitors. Supercapacitors possess fast charge-discharge characteristics, high cycling stability and eco-friendliness in comparison to batteries. But they suffer from extremely low energy density (<10 Wh kg-1), high cost, bulk size, high self-discharge and significant drop in power density while increasing its energy density. The rational synthesis of electrode-materials has a significant impact on the development of high-performance electrodes for energy storage devices. Traditionally semiconducting materials like transition metal oxides are used as pseudocapacitive materials but transition metal oxides have very low electronic and ionic conductivity. Recently, transition metal sulfides, another class of semiconductors, are being investigated as they exhibit better conductivity and reaction kinetics compared to oxides. In this work, α-MnS is selected as an alternative to transition metal oxides. α-MnS is the most stable polymorph among other possible crystal structures of MnS, and has a hexagonal sheet like structure along with high operational potential window than many other metal sulfides. Although it is more conducting than transition metal oxides, it still needs conductivity enhancers like activated carbon, graphene, multiwall carbon nanotubes (MWCNT) etc. External mixing of conductivity enhancers is not effective enough to enhance the conductivity. Hence, MWCNT is mixed during the synthesis step to have a better bonding with α-MnS and create high conductivity channels. α-MnS + MWCNT composite shows a specific capacitance of 115 F g-1 at 1 A g-1 in 3 M KOH electrolyte under 3 electrode configuration. α-MnS + MWCNT composite is deposited on flexible conducting carbon cloth as cathode material and Vulcan carbon is deposited on carbon cloth as anode material. A mixture of poly vinyl alcohol PVA+ 3 M KOH is used as the gel type electrolyte. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), galvanostatic charge discharge (GCD), electrochemical impedance spectroscopy (EIS), cycling stability are performed to characterize the active material and the device performance. The assembled device shows a potential window of 1.4 V, alongside a specific capacitance of 27.7 F g-1 at 1 A g-1 and with 80% of capacity retention after 10,000 cycles. These results prove that transition metal sulfides can be viable alternative materials for supercapacitor application. This quasi-solid state or gel type electrolyte significantly reduces the conductivity and specific capacitance. Enhancing the ionic conductivity of the gel and finding out the optimum thickness of gel electrolyte layer between the electrodes are expected to open new pathways in enhancing the performance of the device. Figure 1

Improving Cell-Level Specific Energy for All-Solid-State Lithium Sulfur Batteries

All-solid-state lithium-sulfur (Li-S) batteries are considered as one of the top choices toward 500 Wh/kg of specific energy, a key metric for an energy storage system that enables large regional electric aircrafts. Many obstacles remain, such as S utilization in the cathode, cyclability with regard to both cathode and anode as well as electrode-electrolyte interfaces, and effective means to increase the S content within the all-solid-state cell architecture. The latter is directly related to cell-level specific energy when considering the weights of all battery cell components. In this presentation, we discuss the efforts in both cathode optimization and cell-level improvement toward increasing the overall specific energy. Various strategies in improving S utilization and reducing the solid electrolyte layer thickness will be presented.

Optimization of Device Parameters for Back‐Contact Transparent Conductive Oxide–Less Dye‐Sensitized Solar Cells Fabrication

Transparent conductive oxide–less (TCO‐less) dye‐sensitized solar cell (DSSC) has been constructed and characterized employing mesoporous TiO2‐coated stainless‐steel mesh (S‐S‐mesh or Mesh) as a bendable photoanode and iodine‐based redox electrolyte. Efforts have been directed toward optimizing electronic parameters to enhance the power conversion efficiency (PCE) of TCO‐less DSSC to equalize its TCO‐based DSSC counterpart. It is found that protection of Mesh is essential for increasing the PCE of TCO‐less DSSCs employing iodine electrolyte as assured by suppressed reverse saturation current and better diode factor. The PCE of 5.6% is obtained with TCO‐less DSSC compared with TCO‐based DSSC with PCE of 6.09%. A bit of decrease in PCE with TCO‐less DSSC is due to larger resistance in TiO2/dye/electrolyte as well as within electrolyte as evident by electrochemical impedance spectroscopy (EIS) study owing to the Mesh having perforated holes and larger thickness of electrolyte absorbing sheet of the porous polytetrafluoroethylene film (35 μm) compared to TCO‐based DSSC without any barriers and lower electrolyte layer thickness of 25 μm.

Material selection in making electrochemical impedance spectroscopy sensor for electrolyte thickness measurement in marine atmosphere

In this work, the material of the electrochemical impedance spectroscopy based (EIS-based) sensor was optimized to achieve in-situ electrolyte layer thickness (hs) monitoring under marine atmosphere. Results show that the sensor made by easy-corrosion materials not only can induce the high-frequency dispersion in EIS curves, but also cause unpredictable evolution of electrolyte conductivity, leading to an inaccurate measurement of hs. Nevertheless, the Ni sensor with a thin and corrosion-resistant oxide film can eliminate those distractions and achieve accurate hs response in dynamic environments. Finally, methods for optimizing EIS-based sensor were summarized, which paves a new way for hs monitoring.

A facile path from fast synthesis of Li-argyrodite conductor to dry forming ultrathin electrolyte membrane for high-energy-density all-solid-state lithium batteries

All-solid-state lithium batteries (ASSLBs), utilizing sulfide solid electrolyte, are considered as the promising design on account of their superior safety and high energy density, whereas the time-consuming preparation process of sulfide electrolyte powders and the thickness of electrolyte layer hinder their practical application. Herein, an innovative ultimate-energy mechanical alloying plus rapid thermal processing approach is employed to rapidly synthesize the crystalline Argyrodite-type conductor Li5.3PS4.3ClBr0.7 (LPSClBr) with superior ionic conductivity (11.7 mS cm−1). Furthermore, to realize the higher energy density of the battery, an ultrathin LPSClBr sulfide electrolyte membrane with superior ionic conductivity of 6.5 mS cm−1 is fabricated with the aid of polytetrafluoroethylene (PTFE) binder and the reinforced cellulose mesh. Moreover, a simple solid electrolyte interphase (SEI) is constructed on the surface of lithium metal to enhance anodic stability. Benefiting from the joint efforts of these merits, the modified ASSLBs with a high cell-level energy density of 311 Wh kg−1 show an excellent cyclic stability. The assembled all-solid-state Li2S/Li pouch cell can operate even under the severe conditions of bending and cutting, demonstrating the enormous potential of the sulfide electrolyte membrane for ASSLBs application.

The effect of dip-coating parameters on the thickness and uniformity of BCZYZ electrolyte layer on porous NiO-BCZYZ tubular supports

The effect of dip-coating parameters on the coating thickness and uniformity have been investigated for BaCe0.7Zr0.1Y0.16Zn0.04O3-δ (BCZYZ) electrolyte on porous NiO-BCZYZ tubular supports. The calculated thicknesses of electrolyte using both pre-fired and full fired tubes' dimensions and both wet and dry weight gains have been compared to the measured ones using Scanning Electron Microscopy (SEM) analysis after full firing. The calculated thicknesses using pre-fired tubes’ dimensions using both wet and dry weight gains are found in a good agreement with the measured thicknesses. The minimum coating thickness of 20.49 ± 3.36 μ with 16% standard deviation (StDev) is achieved using 1.91 mm s−1 (20 step.s-1) withdrawal speed and 30 s dwell time. The most uniform coating layer is obtained using that withdrawal speed and 60 s dwell time, leading 23.14 ± 1.69 μ coating thickness and the minimum StDev% of 7%. Using the polynomial fit between StDev% and dwell time, the minimum StDev% can be achieved at that withdrawal speed has been determined as 80 s. The coating parameters have been optimized as 1.91 mm s−1 withdrawal speed and 80 s dwell time for BCZYZ electrolyte on porous Ni/NiO-BCZY tubular supports.

Counterbalancing light absorption and ionic transport losses in the electrolyte for integrated solar water splitting with III–V/Si dual-junctions

Recently, significant progress in the development of III–V/Si dual-junction solar cells has been achieved. This not only boosts the efficiency of Si-based photovoltaic solar cells but also offers the possibility of highly efficient green hydrogen production via solar water splitting. Using such dual-junction cells in a highly integrated photoelectrochemical approach and aiming for upscaled devices with solar-to-hydrogen (STH) efficiencies beyond 20%, however, the following frequently neglected contrary effects become relevant: (i) light absorption in the electrolyte layer in front of the top absorber and (ii) the impact of this layer on the Ohmic and transport losses. Here, we initially model the influence of the electrolyte layer thickness on the maximum achievable solar-to-hydrogen efficiency of a device with an Si bottom cell and show how the top absorber bandgap has to be adapted to minimize efficiency losses. Then, the contrary effects of increasing Ohmic and transport losses with the decreasing electrolyte layer thickness are evaluated. This allows us to estimate an optimum electrolyte layer thickness range that counterbalances the effects of parasitic absorption and Ohmic/transport losses. We show that fine-tuning of the top absorber bandgap and the water layer thickness can lead to an STH efficiency increase of up to 1% absolute. Our results allow us to propose important design rules for high-efficiency photoelectrochemical devices based on multi-junction photoabsorbers.

Development of Low-temperature SOECs with Excellent Performance for CO2 and H2O Co-Electrolysis

Because of the advantages of high efficiency, safety, pollution-free and the waste gas can be converted into clean fuel (such as methane) in situ [1], using the solid oxide electrolysis cells (SOECs) to co-electrolyze water and carbon dioxide to produce oxygen has great application potential in the aerospace field. As early as the 1960s, NASA has begun to research on the use of SOECs to supply oxygen to astronauts [2]. However, the existing SOECs can only operate in high temperature range (750~850 ºC) with short lifetime and high energy consumption [3]. Therefore, it is urgent to reduce the operating temperature of SOECs in order to extend the operating life and shorten its start-up time, then providing a feasibility guarantee for its service in the aerospace industry.However, lowering the cells’ operating temperature will bring about the problem of low oxygen ion conductivity. There are two strategies to solve this problem. One is to select materials with high oxygen ion conductivity in the low temperature range; the other is to reduce the thickness of the electrolyte layer to shorten the mass transfer distance. Herein, GDC was selected as the thin electrolyte material. And by adjusting the paste ratio of screen-printing method and sintering process parameters, the thickness of the dense electrolyte layer can be reduced to <5 μm. Besides, Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) and GDC are mechanically mixed as the anode materials. The measured ohmic resistance and polarization resistance are only 0.079 and 0.019 Ω·cm2 at 650 ºC, and the maximum output power density reaches 1.229 W/cm2 in SOFC mode. In SOEC mode, the steam and carbon dioxide are injected into the cell at a volume ratio of 3:1. The output current density is as high as 1.2 A/cm2 at 650 ºC under an applied voltage of 1.1 V. All these results confirm that the cells are promising for the applications in low temperature SOECs.

Effects of Flow Channel Arrangement and Electrolyte Thickness on Thermal Stress for Planar Solid Oxide Fuel Cell Stacks

Typical operating temperature for solid oxide fuel cells (SOFC) is between 700~800°C. A large temperature gradient and thermal stress caused by internal losses and electrochemical reactions may cause SOFC stack performance degradation and even structural damage, which has become a hindrance to its applications.In this study, a three-dimensional multiphysics CFD (computational fluid dynamics) model is developed and applied for a planar SOFC stack to study the temperature and thermal stress distribution, as well as effects of structure and design parameters, including the flow channel arrangement (e.g., co- and count-flow) and thickness of the electrolyte layer. The stack is composed of three-unit cells, metallic interconnect layers, sealing and anode/cathode current collectors.The simulation results reveal that the temperature difference in the counter-flow mode is smaller and the thermal stress is lower than those in the co-flow mode. The overall performance of the stack is better when the electrolyte layer thickness becomes smaller, but the stack temperature and the temperature gradient become higher. In addition, a large temperature gradient due to the thin electrolyte layer leads to a significant increase of the thermal stress in the electrolyte. The findings and research method from this study can be applied to optimize the design of the stack structures, by consideration of the maximum thermal stress and its distribution.AcknowledgementsThis work is supported by the National Key Research and Development Project of China (2018YFB1502204), the Ningbo major special projects of the Plan “Science and Technology Innovation 2025” (2018B10048).

Artificial neural network modeling and optimization of the Solid Oxide Fuel Cell parameters using grey wolf optimizer

Using Green and carbon-free energy sources is a new concept in the energy conversion, power generation, and energy management framework. Since there is a relatively small number of neural network applications in the field of fuel cells, especially in the case of solid oxide fuel cells, this work adopts the Artificial Neural Network model for modeling aims according to the empirical datasets. Besides, a new optimization method is applied to optimize the solid oxide fuel cell efficiency. The grey wolf optimizer with fast, robust, and simple features is applied to obtain the optimal operational variables of solid oxide fuel cells. The key operational parameters used for the optimization comprise the thickness of the anode support layer, the porosity of the anode layer, the thickness of the electrolyte layer, and the thickness of the cathode layer. The modeling results compared to the laboratory that confirms the ability of the artificial neural network model and optimization method in parameter identification. Two case study optimization procedure was assessed. Firstly, the variables optimized under the operational temperature of 800 °C and the values of 19 μm, 0.52 mm, 62.16 μm, and 75% are obtained for the electrolyte layer thickness, anode support layer thickness, cathode thickness, and anode support layer porosity, respectively. For the second case study, the power density based on the suggested method maximized up to 28% compared to the experimental results.

On the quality of tape-cast thin films of sulfide electrolytes for solid-state batteries

All-solid-state lithium batteries (ASSLBs) have the potential to increase energy density, improve safety, and allow for lower manufacturing costs compared to conventional, liquid-based Li-ion batteries. The thickness of solid electrolyte (SE) layer dictates the cell-level energy density and it is desirable to make the SE layer as thin as possible while maintaining uniformity and defect-free. Manufacturing a high-quality, thin sulfide SE layer at large-scale, however, is challenging. Previous studies have addressed the compatibility of materials used for manufacturing thin sulfide SE films, paving the way for further investigation of processing conditions and film quality. Here we report a strong correlation between the solid loading of dispersions and the quality of tape-casted thin sulfide SE films. We also demonstrate a method for quantifying the quality of thin SE films by observing both pin-hole defects and larger heterogeneous agglomerations of particles in the films. Our thin sulfide SE films containing ∼5 wt% binder are defect-free and show similar ionic conductivity compared to a cold-pressed, binder-free, thick SE pellet, resulting in an ∼11X reduction of area specific resistance. This work on the solid loading of the dispersion used in a scalable tape casting process provides insight for manufacturing high-quality, thin sulfide SE films and to increase the cell-level energy density of ASSLB.

Ultra-thin free-standing sulfide solid electrolyte film for cell-level high energy density all-solid-state lithium batteries

All-solid-state lithium batteries with high safety and high energy density are one of the most promising next generation energy storage devices. However, the enhancement of energy density of all-solid-state lithium batteries is generally hindered by the thick and heavy solid electrolyte layer. In this work, a 5 nm thick homogeneous polydopamine layer is coated on the Li6PS5Cl electrolyte particles in organic alkali solution, resulting in a modified adhesive particle surface. Free-standing polydopamine-coated Li6PS5Cl thin film with thickness of 35 μm could be achieved by cold pressing. All-solid-state lithium battery with the polydopamine-coated Li6PS5Cl thin film is assembled and exhibits a discharge capacity of 485.1 mAh g−1 after 100 cycles with a capacity retention of 78.5% at 0.1 C and 25 °C. A high full-cell level energy density of 284.4 Wh kg−1 can be realized with reduced thickness and weight of electrolyte layer.

Limiting Current Density of Oxygen Reduction under Ultrathin Electrolyte Layers: From the Micrometer Range to Monolayers

AbstractThe oxygen reduction reaction (ORR) under ultrathin electrolyte layers is a key reaction in many processes, from atmospheric corrosion to energy conversion in fuel cells. However, the ORR current under ultrathin electrolyte layers is difficult to measure using conventional electrochemical methods. Hence, reliable data are scarce for the micrometer range and totally missing for the sub‐micrometer range of the electrolyte layer thickness. Here, we report a novel hydrogen‐permeation‐based approach to measure the ORR current underneath thin and ultrathin electrolyte layers. By using a Kelvin‐probe‐based measurement of the potential, which results from dynamic equilibrium of oxygen reduction and hydrogen oxidation, and the corresponding hydrogen charging current density, the full current‐potential relationship can be constructed. The results shed a new light on the nature of the limiting current density of ORR underneath ultrathin layers of electrolyte.

(Corrosion Division Morris Cohen Graduate Student Award Address) A Systematic Study of Critical Parameters Affecting the Galvanic Corrosion between Al Alloy and Stainless Steel in Atmospheric Condition

Connections between dissimilar materials are frequently encountered in complex structures involved in the aerospace industry. In a typical aircraft structure, one of the most common couples encountered is that of an aluminum-alloy-based airframe component and noble fasteners such as stainless steel. When this type of galvanic couple is exposed to a atmospheric marine environment, it can develop cracks that pose increased risk and require costly maintenance and repair. In this work, a complementary modeling and experimental approach is applied to systematically investigate the effect of electrolyte layer thickness, solution chemistry and materials surface properties on the electrochemical and corrosion distributions in the galvanic coupling between AA7050 and SS316L, and capture the underlying mechanism of the dependence of corrosion distributions on each external variable.To validate the robustness of our modeling approach, a Laplace-Equation based modeling coupled using mathematically-fitted electrochemical kinetics from experiment as boundary conditions was applied to simulate galvanic corrosion between Zn plate and SS 316 rods under thin layer electrolyte conditions. The modeling results were compared with experimental results from a four-day modified B117 test. It shows that: electrolyte layer thickness (WL)=3,500~4, 000 \U0001d707m would be the appropriate WL range formed on the sample surface during modified B117 salt fog testing; the robustness of Laplace-Equation based modeling is highly dependent on the boundary conditions, experimentally-determined electrochemical kinetics as boundary conditions can truly reflect the electrochemical response of anode/cathode to the surrounding solution environment, which in turn yields the simulated results mostly close to experimental measurement.In the study of the effect of electrolyte layer thickness, the total cathode current capacity of a surface on the electrolyte film thickness and cathode size in a galvanic couple to support the corrosion of AA7050 was accessed. The total cathode current capacity was studied over the range of WL thickness from full immersion conditions (where the total cathode current scales directly with cathode size) to the thin film regime in which the WL is the diffusion boundary layer thickness. In order to fully assess the transition from thin film to thick film condition, an understanding of the natural convection layer thickness is required. For the conditions studied here, the natural convection boundary layer was found to be close to 800 um. The WL thickness, cathode length and electrochemical kinetics interact to create four regimes of total cathode current as a function of WL thickness.In the study of the solution chemistry, the effect of Al3+ on the electrochemical and galvanic corrosion distributions between SS316L and AA7050was emphasized as it represents the major dissolved metal species from AA7050. It is found that Al3+ accelerates the hydrogen evolution reaction (HER) kinetics due to enhanced proton diffusivity, with the effect being observed not only on Al alloys, but also on Pt and stainless steel. The cation study for the galvanic couple indicates that Al3+ is also galvanic corrosion accelerator.The effect of oxide film properties on the cathodic kinetics of stainless steel were investigated because cathodic kinetics can significantly affect the degree of galvanic corrosion based on mixed potential theory. The study focused on the oxygen reduction reaction (ORR) and was studied by electrochemical (potentiodynamic polarization, cyclic voltammetry, potentiostatic test, and electrochemical impedance) techniques and x-ray photoelectron spectroscopy surface analysis. This study shows that the kinetics of ORR on stainless steels is determined by a combined effect of oxide film composition, film thickness, and resistivity.This work has improved the fundamental understanding of the effect of several pertinent variables on the galvanic-coupling induced localized corrosion of Al alloy, provided an approachable modeling means to predict corrosion distribution at given conditions in a timely fashion as well as develop corresponding corrosion mitigation strategies, and complemented continuum/meso-scale atmospheric corrosion modeling studies in this field. Acknowledgements The financial support from the Office of Naval Research (ONR) via Grants No. N00014-14-1-0012 and No. N00014-17-1-2033, the Sea-Based Aviation Program, and William Nickerson, Program Manager is gratefully acknowledged. The assistance of my advisor, Prof. R. G. Kelly is gratefully acknowledged. Helpful technical discussions with Profs. S. J. McDonnell, J. R. Scully, and J. T. Burns (University of Virginia), Dr. Jayendran Srinivasan (the Ohio State University), Dr. Piyush Khullar (Medtronic), Dr. Veronica Rafla (SpaceX) and Mr. Victor Yang (University of Virginia) are also acknowledged.

In-Situ GI-XRD of Electrochemically Formed Thin Gold-Oxide Layers

In-situ XRD analysis is a valuable tool to maximize understanding of complex (electro-)chemical reactions while eliminating errors or changes in the structure when instable compounds or materials that react with air are analysed ex-situ. Surface analysis has been a key aspect in the basic research of metal corrosion. Nevertheless, there is more work to be done to achieve complete understanding which is in part because of the lack of proper in-situ analyses. Unfortunately, previous setups for in-situ XRD analysis come along with their own set of problems. In these constructions a low signal/noise ratio can be seen as the beam has to penetrate the electrolyte. High energy synchrotron radiation and long exposure is needed to get information of surface reactions which makes it very laborous and hard to get high quality data. Various researchers like M. Fleischmann et al [1] introduced new XRD cells in which electrolyte layer thickness was minimized to reduce the energy loss and get more accurate XRD information. However, due to issues with current density distribution and other restrictions like depletion of electroactive species or unfavorable reference electrode position electrochemical processes with high reaction rates cannot be investigated accurately in this setup.In a new setup S. Reither et al [2] introduced a XRD cell where copper is sputtered on a XRD-transmittable polyimide foil as a working electrode. The XRD beam is directed through the polyimide and the thin metal film where the reaction happens without passing the electrolyte underneath. A normal electrochemical cell can be used at the side of the working electrode with inlets for counter- and reference electrode. Depending on the reaction rate the setup also includes an in- and outlet to circulate electrolyte if required. Gracing incidence XRD geometry allows for improvement of the signal intensity of thin-film surface reactions.To demonstrate the strength of the setup the oxidation of polycrystalline gold was investigated. Gold is used as the surface reactions are unique compared to other metals due to its stability against oxide formation. L D Burke et al [3] have tried to investigate the reactions taking place at high voltages to create monolayers and thick oxide layers under different conditions. While normal metal oxidation occurs at the surface, gold oxidation occurs beneath a monolayer of adsorbed hydroxy-ions and is catalysed by repulsion triggered ion exchanges at the surface, increasing the influence of conditions and reaction time as well as the current. Our goal is to use the novel in-situ-XRD system to better understand how gold behaves in various electrolytes using both cyclic and constant voltages to create oxide films. It is suspected that gold oxides have porous or amorphous structure. Therefore, a direct XRD-analysis might be difficult. On the other hand, the correlation of electrochemical data with XRD-data allows the indirect categorization between amorphous and crystalline phases at different conditions as pH and temperature.The details of the in-situ XRD-cell as well as its contribution to analysing gold oxide are presented in this contribution.Image explanation:1 .. counter electrode2 .. polymer window with working electrode3 .. reference electrode4, 5 .. solution in- and outlet[1] M. Fleischmann, A. Oliver, and J. Robinson, ‘In Situ X-ray diffraction studies ofelectrode solution interfaces’, Electrochimica Acta, vol. 31, no. 8, pp. 899–906, (1986)[2] S. Reither, W. Artner, A. Eder, S. Larisegger, M. Nelhiebel, C. Eisenmenger-Sittner, G.Fafilek, ‘On the In-Situ Grazing Incidence X-Ray Diffraction of Electrochemically FormedThin Films’, ECS Transactions, 80 (10) 1231-1238, (2017) 10.1149/08010.1231ecst[3] L.D. Burke and P.E Nugent, Electrochim. Acta, 42, 399, (1997) Figure 1

Recent moth-flame optimizer for enhanced solid oxide fuel cell output power via optimal parameters extraction process

Abstract This paper proposes a recent approach-based moth-flame optimizer (MFO) to enhance the output power of solid oxide fuel cell (SOFC) via identifying the optimal parameters of its model. The cell is modeled via artificial neural network (ANN) trained by experimental dataset. Six inputs are fed to ANN to get the SOFC terminal voltage. Levenberg-Marquardt is used in training process with minimizing the mean squared error (MSE). The SOFC model polarization curves are compared to experimental data under variable operating conditions. The proposed MFO is employed to estimate the optimal values of SOFC model, anode support layer (ASL) thickness; ASL porosity; thickness of electrolyte and cathode functional layer (CFL) thickness to enhance the SOFC extracted power. Furthermore, a quantitative and qualitative comparative study with ANN-based SOFC optimized via Genetic Algorithm (GA), Social Spider Optimizer (SSO), Radial Movement Optimizer (RMO) and the experimental data is presented under different operating conditions. Sensitivity analysis is performed by changing the upper and lower thresholds of the estimated variables. The proposed ANN-MFO approach enhanced the SOFC power by 18.92% and 5.56% in comparison with ANN-GA and ANN-RMO respectively. The obtained results confirmed the significance of the proposed MFO in enhancing of the SOFC output power.

Influences of NH4+ ions and thin electrolyte layers (TEL) thickness on the corrosion behavior of AZ91D magnesium alloy

In this study, the influences of NH4 + ions and the thin electrolyte layer (TEL) thickness on the corrosion behavior of the AZ9D magnesium alloy in NH4+‐containing environments were investigated by electrochemical measurements and surface characterization. The experimental results indicate that NH4+ greatly accelerates the corrosion of AZ91D magnesium alloy whether in a bulk solution or in a TEL. As the TEL thickness decreasing, the corrosion resistance of the AZ91D magnesium alloy is strengthened. According to the corrosion morphology, electrochemical analysis, and characterization analysis of corrosion products, the corrosion mechanism of AZ91D under TELs with different thicknesses is divided into three stages: (a) uniformly distributed corrosion pits with deep depth and large size when TEL thickness is higher than or equal to 500 μm; (b) slightly corrosion with randomly distributed corrosion pits and the accumulation of small amount of corrosion product when TEL thickness is between 100 μm and 200 μm; (c) no corrosion pit with only deposition of corrosion product when TEL thickness is lower than or equal to 100 μm. Among which, the roles of NH4+, TEL thickness, and corrosion product are emphasized and discussed in the corrosion process of AZ91D magnesium alloy under TEL with different thicknesses.

Effect of direct current electric field intensity and electrolyte layer thickness on oxygen reduction in simulated atmospheric environment

The effect of direct current (DC) electric field and electrolyte layer thickness on oxygen reduction in simulated atmospheric environment were investigated using electrochemical measurements. The results show that the limiting diffusion current density (ilim) decreases with increasing the thin electrolyte layers (TELs) thickness but it increases with increasing the DC electric field intensity. The potential shifts negatively with the DC electric field. It is found that the DC electric field enables OH− ions to quickly migrate from the solution/electrode interface to the electrolyte layer. All these features promote the cathodic reduction process thereby enhancing the metal corrosion rate.

Corrosion behavior of Sn-3.0Ag-0.5Cu alloy under chlorine-containing thin electrolyte layers

Corrosion behavior of Sn-3.0Ag-0.5Cu lead-free solder alloy under chlorine-containing thin electrolyte layers is studied. The emphasis is laid on discussion about influences of addition of alloying elements, concentration of chloride ion and thickness of electrolyte layer on its corrosion behavior. Results indicate that: mainly local corrosion occurs to the alloy; Existence of intermetallic compounds and β-Sn crystal boundary facilitates the process of Cl− infiltration into the base and galvanic corrosion. Metal ions are accumulated in pitting corrosion region, and hydrolysis of metallic ions promotes the solution acidification and transverse development of pitting corrosion.