Total Polarization Resistance Research Articles

Enhancing oxygen reaction kinetics in lanthanum nickelate Ruddlesden-Popper electrodes via praseodymium oxide infiltration for solid oxide cells.

This study explores the effect of praseodymium oxide (PrOx) impregnation in lanthanum nickelate Ruddlesden-Popper (RP) type materials for use in oxygen electrodes of solid oxide cells (SOCs). These mixed conductors are free of cobalt and strontium, which are increasingly being avoided in solid oxide cell applications. We investigate two compositions, La2NiO4+δ (L2N1) and La4Ni3O10-δ (L4N3), demonstrating distinct electrical and oxygen kinetic properties. The L2N1 material exhibits superior performance due to its higher bulk oxygen-ion diffusion, which governs the enhanced ambipolar conduction, crucial for the oxygen exchange process. In the PrOx-impregnated samples, at 700 °C, the total polarization resistance (Rpol) values decrease to ∼0.6 Ω cm2 for L2N1 + PrOx and ∼0.8 Ω cm2 for L4N3 + PrOx, representing reductions by factors of ∼7 and ∼17, respectively, compared to the non-impregnated counterparts. Electrochemical measurements as a function of oxygen partial pressure suggest that surface-exchange processes may be rate-limiting. The impregnated PrOx acts as a catalyst for the dissociative adsorption of oxygen and improves the charge transfer, leading to significant enhancements in the polarization processes. The electrochemical properties and stability of these RP phases in oxidizing conditions, combined with the oxygen transport capabilities and mixed oxidation state of praseodymium oxide (Pr4+/Pr3+), offer promising Co- and Sr-free oxygen electrodes for SOC applications.

Optimization of misfit calcium cobaltite oxygen electrodes for solid oxide fuel cells through electrospinning processing

The calcium cobaltite (CCO) electrode processed by electrospinning (ES) benefits from reduced grain size and increased grain-to-grain contact, decreasing the total polarization resistance, compared to that produced by Solid State Reaction (SSR).

INFLUENCE OF THE METHOD OF FORMING A Pr2CuO4-BASED CATHODE ON THE ELECTROCHEMICAL CHARACTERISTICS OF A PLANAR ELECTROLYTE-SUPPORTED SOFC

The influence of the method of organising the cathode microstructure based on Pr2CuO4 (PCO) on the electrochemical characteristics of a model electrolyte-supported solid oxide fuel cell (SOFC) has been investigated. It is shown that an increase in the thickness of the PCO cathode layer and the introduction of a pore-forming agent contribute to an increase in the power density of the SOFC test cell compared to a sample with an initial unmodified cathode structure, whose power density at 850°C was 34 mW/cm2. It was found that the optimum thickness of the cathode layer to achieve maximum electrochemical performance was in the range of 40-50 μm, while the power density achieved was 116 mW/cm2 at 850°C. At the same time, the transition from a single-phase PCO cathode to a composite of PCO-Ce0.9Gd0.1O1.95 (60/40 wt. %) provides an increase in power density up to 130 mW/cm2 at 850°C, while the dynamics of its decrease with reducing temperature is slower compared to the single-phase cathode. The analysis of the changes in the values of the total electrode polarisation resistance of the model SOFC, determined by impedance spectroscopy, as a function of the method of cathode formation, showed that during the transition from the initial sample to the samples with increased thickness of the cathode layer and the composite cathode, a twofold (in the first case) and threefold (in the second case) decrease in the level of polarisation losses is observed, which correlates with an increase in the power density. The proposed methods of modifying the initial cathode microstructure based on PCO show a positive dynamic of increasing the electrochemical activity of the cathode/electrolyte interface and the power density characteristics of the fuel cell as a whole.

Architecture design of TiO2 with Co-doped CdS quantum dots photoelectrode for water splitting.

Photoelectrochemical hydrogen production is a critical key to solving the carbon-zero goal of countries due to renewable sources of solar light and combustion products of hydrogen-only water. Here, an architecture design for an n-type nano rosettes-rod TiO2 (RT) surface using CdS and Co-doped CdS quantum dots (QDs) is carried out utilizing the SILAR (simple ionic layer adsorption and reaction) method. Furthermore, the photocatalytic behaviour of Co-doped CdS QDs SILAR cycles deposition is investigated in various cycles, including 5, 8, 10, and 12. The FESEM, Raman XRD, Uv-Vis spectrometer, and vibration modes are used to evaluate the photoelectrode surface structure, crystal structure, and solar light absorption, respectively. FESEM images and XRD pattern revealed successive CdS QDS and Co-doped CdS QDs deposition on the RT boundary and rising SILAR cycles of Co-doped CdS QDs lead to further coverage of RT surface. UV-vis spectrometer indicated shifting solar light absorption to the visible region by applying more SILAR cycles of Co-doped CdS QDs deposition. The electrochemical parameters obtained from EIS showed total polarization resistance (Rp) of the RT electrode dramatically decreased with 10 SILAR cycle Co-doped CdS QDs deposition (5093 Ω cm2 and 617 Ω cm2). Linear sweep voltammetry (LSV) and chronoamperometric photocatalytic performance measurements indicated Co-doped CdS QDs on RT extremely enhanced photoresponse under solar irradiation and 10 SILAR cycle Co-doped CdS QDs improved photocurrent density about fourfold according to blank RT electrode.

B-Site Super-Excess Design Sr2V0.4Fe0.9Mo0.7O6-δ-Ni0.4 as a Highly Active and Redox-Stable Solid Oxide Fuel Cell Anode.

In-situ exsolution type perovskites as solid oxide fuel cell (SOFCs) anode materials have received widespread attention because of their excellent catalytic activity. In this study, excessive NiO is introduced to the Sr2V0.4Fe0.9Mo0.7O6-δ (SVFMO) perovskite with the B-site excess design, and in-situ growth of FeNi3 alloy nanoparticles is induced in the reducing atmosphere to form the Sr2V0.4Fe0.9Mo0.7O6-δ-Ni0.4 (SVFMO-Ni0.4) composite anode. Here, with H2 or CH4 as SOFCs fuel gas, the formation of FeNi3 nanoparticles further enhances the catalytic ability. Compared with SVFMO, the maximum power density (Pmax) of Sr2V0.4Fe0.9Mo0.7O6-δ-Ni0.4 (SVFMO-Ni0.4) increases from 538 to 828 mW cm-2 at 850 °C with hydrogen as the fuel gas, and the total polarization resistance (RP) decreases from 0.23 to 0.17 Ω cm2. In addition, the long-term operational stability of the SVFMO-Ni0.4 anode shows no apparent performance degradation for more than 300 h. Compared with SVFMO, the Pmax of SVFMO-Ni0.4 increases from 138 to 464 mW cm-2 with methane as fuel gas, and the RP decreases from 1.21 to 0.29 Ω cm2.

Enhancement of Ni-YSZ Fuel Electrode Performance Via Pressurization and GDC Infiltration

Solid oxide cell systems are often designed for operation with a pressurized stack. Although the cell performance is expected to improve with pressurization, the details of how pressure affects the performance of various technologically-relevant electrodes are typically not known. Here we investigate the electrochemical characteristics of Ni-YSZ and GDC-infiltrated Ni-YSZ fuel electrodes in Ni-YSZ-supported cells as a function of total pressure P from 1 to 5 atm in H2/H2O fuel mixtures with humidification of 25%, 50%, and 75% and temperatures of 600˚C and 700˚C. Using electrochemical impedance spectroscopy, the two limiting electrode processes are identified: charge transfer reactions and gas diffusion. The charge transfer resistance is significantly reduced for Ni-YSZ:GDC compared to Ni-YSZ for all conditions, with total polarization resistance RP reduced by 30 - 40%. Fitting the data to a power-law dependence, RP ∝ P−n, yields a power law exponent of n = 0.28 for Ni-YSZ and 0.36 for Ni-YSZ:GDC (at 600˚C) and n = 0.32 for Ni-YSZ and 0.39 (at 700˚C). That is, GDC infiltration improved electrode performance more at higher pressure. Increasing the total pressure from 1 to 5 atm results in a 42% and 47% reduction in RP for infiltrated electrodes at 600˚C and 700˚C; these values are averaged for all humidities. Increasing humidity from 25 to 50% at 1 atm resulted in a ~26% reduction in total RP. The Ni-YSZ:GDC electrode at 5 atm had a RP value 63% - 65% lower than that of the Ni-YSZ electrode at 1 atm, a very substantial combined effect. The impact of pressurization on overall cell area-specific resistance is assessed based on the present data combined with prior measurements of oxygen electrode pressurization effects.

Non-Linear Kinetics of The Lithium Metal Anode on Li6 PS5 Cl at High Current Density: Dendrite Growth and the Role of Lithium Microstructure on Creep.

Interfacial instability, viz., pore formation in the lithium metal anode (LMA) during discharge leading to high impedance, current focusing induced solid-electrolyte (SE) fracture during charging, and formation/behaviour of the solid-electrolyte interphase (SEI), at the anode, is one of the major hurdles in the development of solid-state batteries (SSBs). Also, understanding cell polarization behaviour at high current density is critical to achieving the goal of fast-charging battery and electric vehicle. Herein, via in situ electrochemical scanning electron microscopy (SEM) measurements, performed with freshly deposited lithium microelectrodes on transgranularly fractured fresh Li6PS5Cl (LPSCl), the LiǀLPSCl interface kinetics are investigated beyond the linear regime. Even at relatively small overvoltages of a few mV, the LiǀLPSCl interface shows non-linear kinetics. The interface kinetics possibly involve multiple rate-limiting processes, i.e., ion transport across the SEI and SE|SEI interfaces, as well as charge transfer across the LiǀSEI interface. The total polarization resistance RP of the microelectrode interface is determined to be ≈ 0.8 Ω cm2 . It is further shown that the nanocrystalline lithium microstructure can lead to a stable LiǀSE interface via Coble creep along with uniform stripping. Also, spatially resolved lithium deposition, i.e., at grain surface flaws, grain boundaries, and flaw-free surfaces, indicates exceptionally high mechanical endurance of flaw-free surfaces toward cathodic load (>150mA cm-2 ). This highlights the prominent role of surface defects in dendrite growth.

Enhancement of Ni-YSZ Fuel Electrode Performance Via Pressurization and GDC Infiltration

Ni–(Y2O3)0.08(ZrO2)0.92 (YSZ) and Ce0.8Gd0.2O2 - δ (GDC) infiltratedNi-YSZ fuel electrodes are investigated using impedance spectroscopy as a function of total pressure P from 1 to 5 atm in 25%, 50%, and 75% humidified H2 mixtures at a temperature of 600˚C. The charge transfer resistance decreases significantly with infiltration for all conditions, and the total polarization resistance RP is reduced by ~20%. Fitting the P dependence to a power-law, RP ∝ P−n, yields an exponent of ~0.21 for both un-infiltrated and infiltrated tests. Increasing the total pressure from 1 to 5 atm results in an average 29% reduction in RP for both electrodes. Increasing the humidification from 25 to 75% generally results in a reduction in RP. The Ni-YSZ:GDC electrode at 5 atm had a RP value ~44% lower than that of the Ni-YSZ electrode at 1 atm, a substantial combined effect.

Impedance of a tubular electrochemical cell with BZCY electrolyte and Ni-BZCY cermet electrodes for proton ceramic membrane reactors

In this work, impedance spectroscopy has been employed to explore the electrochemical behaviour of a 15 cm2 complete tubular cell with BaZr0.8Ce0.1Y0.1O3-δ (BZCY) electrolyte and two asymmetric Ni-BCZY cermet electrodes for hydrogen separation. Analyses of impedance spectra at different temperatures and gas compositions reveal that the thick inner electrode contributes most to the total polarisation resistance (Rp). For Rp there are four contributions with well-separated time constants of which gas phase hydrogen diffusion within the porous Ni-BZCY anode is predominant. The other three can be ascribed to proton migration through the space charge layer of the BZCY electrolyte adjacent to the Ni electrode, hydrogen redox charge transfer reactions, and hydrogen diffusion within Ni bulk. The present study guides the way to parameterise and, on this basis, optimise electrodes for scalable proton ceramic electrochemical cells.

Ba2NiMoO6-δ as a potential electrode for protonic ceramic electrochemical cells

A novel layered double perovskite-based electrode of composition Ba2NiMoO6-δ (BNMO) is proposed for application in Protonic Ceramic Electrochemical Cells (PCECs). Structural characterization by X-ray diffraction (XRD) revealed good chemical compatibility with a BaCe0.7Zr0.1Y0.2O3-δ (BCZY712) electrolyte and phase stability in oxidizing atmospheres. In this study, symmetrical cells of both the pure BNMO electrode and a composite electrode with 50 vol% of BCZY712 material were prepared by screen printing and sintering in air at 950 °C. Microstructural characterization by Scanning Electron Microscopy (SEM) showed good adhesion of the electrode films with the substrate, while Energy-dispersive Spectroscopy (EDS) revealed good percolation of both phases in the case of the composite electrode. Electrochemical studies made by Electrochemical Impedance Spectroscopy (EIS) on the pure BNMO electrode demonstrated that the total polarization resistance was lower in wet conditions in the case of N2 atmospheres, corroborating a potential protonic contribution, while in O2 atmospheres this term was similar between wet and dry conditions, due to dominant p-type electronic conductivity. Conversely, performance was aggravated by the addition of the BCZY712 composite phase; a result clarified to be due to an insufficient level of electronic conductivity in the composite electrode. To the best of our knowledge this is the first study of BNMO for proton conducting applications, providing important information on preparation, compatibility and electrochemical performance, as required for its further optimization.

A novel symmetrical bi-electrode supported ceramic oxygen pump for efficient oxygen production

Based upon the solid oxide electrolysis cell (SOEC) technology, ceramic oxygen pumps (COPs) show great promise owing to their distinctive advantage of continuous and in situ production of high-purity oxygen with control easiness. Here we report on the fabrication of novel ceramic oxygen pumps by the phase-inversion tape casting, lamination and co-firing methods, featuring thin yttria-stabilized zirconia (YSZ) electrolytes supported on symmetrical La0.8Sr0.2 MnO3-δ (LSM)-YSZ electrodes with straight open pores. A current density of 0.33 A•cm−2 is obtained at 750°C and 0.6 V for the ceramic pumps to separate oxygen out of air. Impregnating nano-scale La0.6Sr0.4CoO3-δ (LSC) catalysts into both LSM-YSZ electrodes yields a sharp increase in the performance. For example, the pumping current density at 750°C and 0.6 V increases by a factor of 8 to 2.56 A•cm−2. The total interfacial polarization resistance decreases from 1.17 Ω•cm2 by a factor of 20 to 0.06 Ω•cm2. Analysis of impedance data in the homogeneous environments of air and oxygen indicates that the oxygen separation capability is predominantly limited by the surface oxygen exchange kinetics, which is substantially promoted by the added LSC catalysts. Preliminary short-term measurements show good stability in oxygen separation, indicating excellent resistance of the nano-scale LSC catalysts against coarsening at elevated temperatures. Furthermore, the present symmetrical ceramic oxygen pumps also demonstrate excellent thermal cycling durability.

PGM-Free Electrocatalytic Layer Characterization by Electrochemical Impedance Spectroscopy of an Anion Exchange Membrane Water Electrolyzer with Nafion Ionomer as the Bonding Agent

Low-cost anion exchange membrane (AEM) water electrolysis is a promising technology for producing “green” high-purity hydrogen using platinum group metal (PGM)-free catalysts. The performance of AEM electrolysis depends on the overall overvoltage, e.g., voltage losses coming from different processes in the water electrolyzer including hydrogen and oxygen evolution, non-faradaic charge transfer resistance, mass transfer limitations, and others. Due to the different relaxation times of these processes, it is possible to unravel them in the frequency domain by electrochemical impedance spectroscopy. This study relates to solving and quantifying contributions to the total polarization resistance of the AEM water electrolyzer, including ohmic and charge transfer resistances in the kinetically controlled mode. The high-frequency contribution is proposed to have non-faradaic nature, and its conceivable nature and mechanism are discussed. The characteristic frequencies of unraveled contributions are provided to be used as benchmark data for commercially available membranes and electrodes.

Study of the efficiency of composite LaNi0.6Fe0.4O3-based cathodes in intermediate-temperature anode-supported SOFCs

The paper focuses on the performance comparison of LaNi0.6Fe0.4O3-δ (LNF) composite cathodes comprising Ce0.8Sm0.2O1.9 (SDC) and Bi1.5Y0.5O3 (YDB) electrolytes and La0.6Sr0.4Fe0.8Co0.2O3-δ (LSFC)-SDC cathodes in anode-supported SOFCs with YSZ/GDC electrolyte films obtained by magnetron sputtering. Cathodes with LNF-SDC and LNF-YDB functional layers and the LNF-YDB-CuO oxide collector show a sufficient thermo-mechanical compatibility with the electrolyte. The performance of the anode-supported SOFC with the LNF-YDB/LNF-YDB-CuO cathode, reaches 650 and 1050 mW/cm2 at 700 and 800 °C, respectively, which is significantly higher than that obtained in other works for anode-supported cells with LNF cathodes. The initial total polarization resistance of the NiO-YSZ/YSZ/GDC/LNF-YDB/LNF-YDB-CuO cell, is 0.53 Ω cm2, which is lower than the initial resistance of the similar anode-supported cell with the LNF-SDC/LNF-YDB-CuO cathode (1.35 Ω cm2) and LSFC-SDC cathode with LNF-YDB-CuO (1.71 Ω cm2) and La0.6Sr0.4CoO3 (1.17 Ω cm2) collectors. The most probable reason for the LNF-YDB electrode aging is the growth of Bi-containing particles. Experimental results show that LNF-based composite cathodes are competitive with cobalt-containing cathodes and can be promising for anode-supported SOFCs with decreased operating temperature, that allows extending the material choice for both functional and collector cathode layers.

On the Operational Conditions’ Effect on the Performance of an Anion Exchange Membrane Water Electrolyzer: Electrochemical Impedance Spectroscopy Study

The performance of an anion exchange membrane water electrolyzer under various operational conditions (including voltage, KOH-supporting electrolyte concentration, and flow rate) is studied using conventional time-domain technics and electrochemical impedance spectroscopy (EIS). The water electrolyzer EIS footprint, depending on the variation in operational conditions, is studied and discussed, providing valuable data on the faradaic and non-faradaic processes in MEA, considering their contribution to the total polarization resistance. The distribution of the AEMWE cell voltage contributions is valuable to accessing the key directions in the system performance improvement.

One-pot impregnation to construct nanoparticles loaded scaffold cathode with enhanced oxygen reduction performance for LT-SOFCs

Constructing nanoparticles loaded scaffold cathode is an effective strategy to reduce the polarization resistance of cathode for Low-temperature Solid Oxide Fuel Cells (LT-SOFCs). Here, self-assembled Ce0.9Gd0.1O2-δ (GDC) microrods were prepared by liquid precipitation method, and used for constructing cathode scaffold. There are interconnected micron level pores with the porosity up to 81.03% in the cathode scaffold, benefitting for directly impregnating solution and even nanoparticles, and gaseous oxygen transport under cell testing. The electrochemical impedance spectra and corresponding distribution of relaxation times results reveal that the porous and continuous distribution of La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF) nanoparticles loaded on GDC scaffold via one-pot impregnation could significantly provide the rapid gas diffusion, abundant adsorption sites, enough reactive sites and unobstructed ionic/electronic conduction to obtain the excellent oxygen reduction performance under lower operating temperatures. The cathode with the GDC scaffold impregnated the LSCF nanoparticles only one time exhibits the total polarization resistance of 0.293 Ω·cm2, significantly less than 0.615 Ω·cm2 of the traditional cathode at 600 °C. The porous nanoparticles loaded scaffold cathode with simple preparation process and excellent oxygen reduction performance is expected to promote the further development of LT-SOFCs.

Identification of internal polarization dynamics for solid oxide fuel cells investigated by electrochemical impedance spectroscopy and distribution of relaxation times

Reliability and durability are two major problems restricting for Solid oxide fuel cells (SOFCs) industrial applications. To ensure the long-term stability, understood the internal operation mechanism of SOFC was necessary. The polarization curve combined with the distribution of relaxation times (DRT) method to analyze the electrochemical impedance spectroscopy (EIS) was used to identify the SOFCs modulation and degradation effect through the excitation frequency. Dynamic evolution of carbon deposition process and specific time constants were determined employing EIS and DRT. Special attention was paid to the dependency between the complex reaction processes that occur during the different operation of SOFC. The corresponding frequencies of concentration and activation polarization resistances in EIS were investigated under various gas compositions. The high concentration polarization resistance caused by the addition of nitrogen and hydrogen starvation was the key limiting factor for high cell power density. The total polarization resistance increased from 1.50 Ω/cm2 to 5.26 Ω/cm2 when the H2:N2 ratio decreased from 1:0 to 1:5. The anode did not deteriorate due to the poisoning of Ni particles in a short-term tested under 0.5 A/cm2 current density when the fuel was methane.

Synthesis and characterization of phenolphthalein derivatives, detailed theoretical DFT computation/molecular simulation, and prevention of AA2024-T3 corrosion in medium 3.5% NaCl

BackgroundAluminum alloy corrosion prevention is a significant problem in the industry. The development of an effective protection strategy is a popular research area. In this work, two organic inhibitors phenolphthalein (P1) and (3-oxo-1, 3-dihydroisobenzofuran-1,1-diyl)bis(4,1-phenylene) bis(4-methyl benzenesulfonate) (P2) were used in 3.5% NaCl medium for alloy AA2024-T3 corrosion mitigation. Corrosion inhibition behavior was investigated by a combination of experimental and theoretical studies. MethodsThe surface morphology of AA2024 -T3 has been identified by scanning electron microscopy coupled with Energy Dispersive X-Ray Spectroscopy (SEM/EDS), and Infrared spectroscopy (FT-IR) confirms the adsorption of functional groups on the surface of the aluminum alloy. Furthermore, the adsorption energies of P1 and P2 on Aluminium (111) interfaces were computed by Molecular Dynamics (MD), and quantum chemical computations (density functional theory, DFT) were chosen for obtaining basic electronic/atomic-scale details about the compound adsorption on target alloy aluminum and their active sites. Significant findingsThe effect of two organic inhibitors phenolphthalein (P1) and (3-oxo-1, 3-dihydroisobenzofuran-1,1-diyl)bis(4,1-phenylene) bis(4-methyl benzenesulfonate) (P2) on the corrosion protection of Aluminium alloy in 3.5% NaCl solution was examined using electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization (PPD) methods. The Total polarization resistance (RTot) increased, and the corrosion current density declined with the increasing inhibitor concentration. Inhibition efficiency revealed the maximum value of 85% for the P1 and 93% for P2 at 10−4 M, respectively. the two inhibitors were categorized as mixed-type inhibitors since they inhibited both cathodic and anodic corrosion.

Enhancement corrosion resistance of mild steel in 15% HCl solution by a novel bio-based polyurethane for oil well acidizing

A novel thermally stable inhibitor was developed based on citric acid and glucose (CAGCI) to inhibit the corrosion of mild steel (MS) in simulated acidic oilfield water for oil well acidizing. All electrochemical measurements were performed in a temperature range of 293–363 K to evaluate the inhibition power of CAGCI. The results of electrochemical tests clearly revealed that CAGCI effectively inhibited MS corrosion via a mixed-type mechanism and 77 × 10−4 M of the inhibitor provided the highest inhibition efficiency of 90%, 93.6%, 93.7%, and 89.9% at 293 K, 313 K, 333 K, and 363 K, respectively. In addition, CAGCI provided a total polarization resistance of 416.7 Ω cm2 for MS at 293 K and decreased the corrosion rate of the metal 7.6 times compared to blank at 363 K. Moreover, the UV–visible results demonstrated the formation of the Fe2+-CAGCI complex and the results of the surface analysis confirmed the presence of a protective film of CAGCI molecules on the MS surface. Finally, the experimental outcomes were well complemented by results obtained from density-functional study and molecular dynamics (MD) simulation. According to quantum calculations, citric acid and aromatic rings in the structure of CAGCI played the main role in electron exchanges with the MS surface. The results of the MD simulation were also confirmed that a hydrophobic barrier can be formed by CAGCI molecules on the MS surface with a parallel adsorption configuration.

Superhydrophobic films-based nonanyl carboxy methylcellulose grafted polyacrylamide for AISI-stainless steel corrosion protection: Empirical explorations and computational models

The current work offers an alternate environmental and facile technique to fabricate a thin coating based on the superhydrophobic film of Nonanyl carboxy methylcellulose grafted polyacrylamide (NCMC-g-PAAm-SB) which could be applied as protective layers for AISI-stainless steel corrosion. FTIR and FESEM apparatuses were used to characterize the synthesized NCMC-g-PAAm-SB. Furthermore, water uptake measurements were tested to prove the hydrophobicity character of NCMCPAAm. The thermal permanence of the NCMC-g-PAAm-SB was detected by thermo-gravimetric examination (TGA) display thermal steadiness up to 250 °C. The anticorrosive performance of the pristine and coated AISI-steel was estimated in a combination of diverse chloride solution, 3.5% NaCl + 1.0 M HCl. PDP, EIS, and potential-time experiments were performed to assess the corrosion protection features. Moreover, LPR corrosion rate tests were completed for the long-term to determine the stability of coating films in the corrosive medium. The impact of the film thickness (number of coating layers) on the corrosion characteristics was inspected. The total polarization resistance increased to 1560.3 Ω cm2 for AISI-steel coated with the NCMC-g-PAAm-SB five layers compared to 55.8 Ω cm2 for pristine AISI-steel, displayed outstanding anticorrosion behavior with 96.4% of protection capacity. FESEM was utilized to describe the surface topology of the uncoated and coated AISI-steel samples before and after exposure in the aggressive medium. The computational models were accomplished to extremely examine the corrosion protection coating mechanism of AISI-steel. Owing to their remarkable physicochemical characteristics, such superhydrophobic films are an economically and innovative accessible substitute to progress the stainless of AISI-steel corrosion resistance and can be utilized in steel protection in acidic chloride environments.

Sr Substituted La2−xSrxNi0.8Co0.2O4+δ (0 ≤ x ≤ 0.8): Impact on Oxygen Stoichiometry and Electrochemical Properties

Lanthanide nickelate Ln2NiO4+δ (Ln = La, Pr, or Nd) based mixed ionic and electronic conducting (MIEC) materials have drawn significant attention as an alternative oxygen electrode for solid oxide cells (SOCs). These nickelates show very high oxygen diffusion coefficient (D*) and surface exchange coefficient (k*) values and hence exhibit good electrocatalytic activity. Earlier reported results show that the partial substitution of Co2+ at B-site in La2Ni1−xCoxO4+δ (LNCO) leads to an enhancement in the transport and electrochemical properties of the material. Herein, we perform the substitution at A-site with Sr, i.e., La2−xSrxNi0.8Co0.2O4+δ, in order to further investigate the structural, physicochemical, and electrochemical properties. The structural characterization of the synthesized powders reveals a decrease in the lattice parameters as well as lattice volume with increasing Sr content. Furthermore, a decrease in the oxygen over stoichiometry is also observed with Sr substitution. The electrochemical measurements are performed with the symmetrical half-cells using impedance spectroscopy in the 700–900 °C temperature range. The total polarization resistance of the cell is increased with Sr substitution. The electrode reaction mechanism is also studied by recording the impedance spectra under different oxygen partial pressures. Finally, the kinetic parameters are investigated by analyzing the impedance spectra under polarization. A decrease in exchange current density (i0) is observed with increasing Sr content.