Grishin et al. have shown [1] the role of the atmosphere composition in the stability of Sm-doped ceria/Molten Carbonates as electrolyte. Transport species, mechanisms and a focus on the interface role have been evidenced, explaining the origin of an exalted conductivity of 0.1 S.cm -1 above 500°C. The partial transformation of carbonates into hydroxides during the first heating/cooling cycle was accelerated by progressively adding hydrogen and even more water vapor. Nevertheless, it was fully inhibited when CO 2 was used. This previous work was conducted because of numerous controverses dealing with this approach in mixing both, molten salts and solid oxide phases as promising electrolyte for Intermediate Temperature-Solid Oxide Fuel Cell, assuming first protonic conduction in the molten carbonate phase and oxide ion conductivity through the solid oxide phase [2]. Based on Grishin’s results, electrode compositions and operating atmospheres have been adapted, leading progressively to performances such as 0.35 W.cm -2 and 0.48 A.cm -2 at 0.7 V and at 650°C as power density and current density, respectively. These performances have been obtained with symmetrical as-synthesized cells, based on (Li,Na,K) 2 CO 3 ternary eutectic mixture associated to Sm-doped ceria as electrolyte, on which are co-pressed electrode powders prepared by nitrates/urea auto-combustion. Hybrid electrodes are based on the electrolyte and Ni-based metallic alloy as hydrogen electrode and NiO-based composite as air electrode. A combination between MCFC and SOFC atmospheres has been defined, noted here (SO-MC)FC. A better shaping is under investigation to improve electrodes microstructures and thus single cells performances. In the current work, the evolution of the single cell architecture and the corresponding performances will be presented. It is worth mentioning that the total electrode area specific resistance is of 0.2 Ω.cm 2 at 650°C, which is a highly promising result (Figure 1). The choice has been done to show also the reversibility between fuel cell and water electrolysis modes, as presented in Figure 2. Furthermore, other fuels such as ammonia are tested in order to deal with the fuel transport challenges. Preliminary studies present encouraging performances with this cell configuration, requiring much attention and further investigations. References [1] A. Grishin, A. Ringuedé, Deeper Understanding of Ternary Eutectic Carbonates/Ceria-Based Oxide Composite Electrolyte through Thermal Cycling, Energies , 15 (7), 2688 (2022) [2] B. Zhu, Functional ceria–salt-composite materials for advanced ITSOFC applications, Journal of Power Sources , 114, 1 (2003) Ackowledgements. The authors would like to thank PSL (doctoral school ED621 and ED388) for funding Lamis Atwi and Simon Hubert. They also acknowledge the financial support from the French national research agency through the project POSEYDON-Grant number ANR-21-CE05-0025 Figure 1

Global energy demand has increased significantly due to world population growth and the industrialization of developing economies. Its production has been based mainly on fossil-fuel energy, increasing the global warming effect upon the rise of greenhouse gases in the atmosphere, such as carbon dioxide (CO 2 ). In this context, the International Energy Agency reported that the global temperature will increase by 2.7 °C by 2100, which can be decreased by using renewable energies, as written by the United Nations Framework Convention on Climate Change. Moreover, according to the last report of the Intergovernmental Panel on Climate Change, it is crucial to substantially reduce CO 2 emissions and other greenhouse gases to improve air quality and stabilize global temperatures. However, nowadays, world energy generation from renewable resources, such as wind, solar, hydroelectric, biomass, tidal, and geothermal, only corresponds to 40%. Fuel cell technology is an excellent opportunity for reducing the dependence on fossil fuels and carbon footprint production. FC uses clean energy with a high conversion efficiency and system configuration that facilitates the easy capture of CO 2 . Different FC exists according to the operation temperature, the electrolyte chemical nature, and the fuel, increasing the conversion efficiency at higher temperatures, such as in Molten Carbonate Fuel Cells and Solid Oxide Fuel Cells, or even more recent Hybrid Fuel Cells, combining both previously mentioned technologies. Although FC has existed for decades, challenges exist to improve its efficiency. Therefore, developing new functional materials for innovative devices or applications is crucial in our changing world. New paradigms are necessary to produce cleaner energy or cheaper and more efficient materials for transport or other domains. This work focuses on the corrosion performance of a nickel-aluminum bronze alloy (NAB) obtained by laser powder bed fusion exposed to molten carbonate at high temperatures under a hydrogen/nitrogen atmosphere. Using electrochemical measurements and surface analyses, NAB samples were monitored before and after 120 hours of exposure between 550 and 650 °C. Scanning electron microscopy and X-ray photoelectron spectroscopy of NAB demonstrated that an oxide film was formed on the NAB surface, rich in Al 2 O 3 and Cu 2 O. Open circuit potential and impedance analysis of NAB revealed that the oxide film was stable under the exposure condition. In addition, the impedance analyses showed a capacitive behavior associated with a porous behavior, relate to the oxide film, and a Warburg impedance.

For more than a century, alkaline electrolyzers and fuel cells (AEL and AFC) have been widely used due to their considerable power densities and lifetimes. However, AFCs encounter issues in managing liquid electrolytes, in operating at higher temperatures, and tolerating carbon dioxide. To solve these limitations a hybrid fuel cell is presented that uses a composite electrolyte containing solid oxide and molten hydroxide phases to operate at intermediate temperatures (400-600 degrees C). These materials are particularly interesting due to their potential to reduce the operating temperature of fuel cells while maintaining high power densities and conductivities. Previous research on oxide-carbonate composites found conductivity of 0.1 Scm(-1) at 600 degrees C. This paper focuses on the development of a new composite electrolyte based on solid oxide-molten hydroxide for hybrid fuel cells. Specifically, the hybrid system composed of samarium-doped ceria (SDC) and different hydroxides (LiOH, NaOH) was studied using a series of thermal, vibrational and electrochemical analyses in different operating conditions. A detailed examination of the electrolyte using differential scanning calorimetry was done to identify the phase transformation temperatures and the stability conditions for the hydroxide phase. A high conductivity of 0.04 Scm(- 1) was achieved with an SDC-NaOH (70-30 wt%) composite in a reducing H-2 atmosphere at 400 degrees C. Several challenges remain, particularly in the selection of new electrode materials and ensuring their long-term stability.

Stretchable elastic materials with high strength, toughness, and good ionic conductivity are highly desirable for wearable devices and stretchable batteries. Unfortunately, limited success has been reported to attain all of these properties simultaneously. Here, we report a family of ionically conductive elastomers (ICEs) without compromise between mechanical properties (high stiffness, reversible elasticity, fracture resistance) and ionic conductivity, by introducing a multiple network elastomer (MNE) architecture into a low T g polymer. The ICEs with the MNE architecture exhibit a room temperature ionic conductivity of the order of 10 - 6 S . cm - 1 and stress at break of ~8 MPa, whereas the simple networks without an MNE architecture show two orders magnitude lower ionic conductivity ( 10 - 8 S . cm - 1 ) and comparably low strength (<1.5 MPa) at 25 °C than their MNE architecture based counterparts. The MNE architecture with a low T g monomer combines the stiffness and fracture toughness given by sacrificial bond breakage while improving ionic conductivity through increased segmental mobility.

The ability to predict the thermal properties of molecular compounds is essential for their successful integration into vapor-phase processes such as atomic layer deposition (ALD) and chemical vapor deposition (CVD), as well as in catalysis and materials synthesis. In this work, we present a systematic study of 24 gallium amidinate complexes, designed to explore the relationship between molecular structure and thermal behavior. The series encompasses a range of structural variations: different ligand substituents, molecular symmetry, and co-ligands. Structural characterization, including in some cases single-crystal X-ray diffraction, was combined with detailed thermal analysis using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) under both atmospheric and reduced pressure conditions. The results reveal clear correlations between thermal properties and ligand architecture, with features such as alkyl chain type, methyl group presence, and overall symmetry playing key roles in determining volatility and stability. Importantly, both symmetric and dissymmetric complexes were found to possess the desired thermal characteristics for vapor-phase deposition processes. Beyond offering valuable design principles for gallium precursors, the dataset generated herein provides a foundation for improving predictive models-empirical and AI-driven alike-towards the rational development of next-generation functional molecular compounds.

The cement industry, responsible for 8% of global greenhouse gas emissions, necessitates developing sustainable materials to replace cement partially. This investigation examined the feasibility of using copper tailings, a byproduct of mining, as alternative materials for cement within mortars and reinforced mortars (0-15wt.%). The microstructural composition of the tailings was analyzed using scanning electron microscopy and X-ray diffraction. The corrosion resistance of mortars reinforced with copper tailings was elucidated through open-circuit potential measurements and electrochemical impedance spectroscopy. The results showed that incorporating 5 and 10wt.% of sieved copper tailings improved the mechanical strength and significantly enhanced the electrochemical stability, as indicated by more noble open-circuit potential values. Specifically, the sieved tailings played a crucial role in forming a more stable oxide film, which was confirmed by higher impedance values, suggesting a reduced corrosion rate. In contrast, mortars with 5wt.% of milled tailings exhibited properties like those of the control group. This electrochemical understanding highlights the potential of processed copper tailings in mitigating the environmental impact of cement production and enhancing the durability of cementitious composites.

Two new acentric oxycarbonates Na6Li4MO4(CO3)4 (M = W and Mo) were synthesized via a conventional solid-state route. Their structure was determined from X-ray diffraction data on single crystals. Na6Li4MO4(CO3)4 (M = W and Mo) crystallizes in the acentric cubic P-43m space group (a ≈ 7.15 Å). It is composed of MLi4O16 units built from MO4 and LiO4 tetrahedra and linked by CO32- groups to form a three-dimensional framework in which Na+ ions are inserted. We showed from differential scanning calorimetry and powder X-ray diffraction experiments that the melting is congruent (T ∼525 °C). In the solid and molten forms, conductivity was measured for both oxycarbonates by electrochemical impedance spectroscopy with three various gas compositions (CO2 100 vol %, CO2-air 70-30 vol %, and CO2-air 20-80 vol %). Each time, the stability of the electrical behavior was checked via heating and cooling cycles. The conductivity of both solid and molten phases is purely ionic and in the same order of magnitude as for the classical molten alkali electrolyte made of Li-Na or Li-K carbonates. As activation energies are also comparable, those new oxycarbonates appear to be promising electrolytes for electrochemical devices.

In the current context of ecological transition, alternative fuels are at the forefront. In particular, interest in high-temperature electrochemical devices such as fuel cells (FC) for the production of carbon-free electricity or electrolysers (EC) of water vapor and/or CO2 is growing. This article therefore aims to take stock of the two main high-temperature systems, namely solid oxide cells (SOFC/SOEC) or molten carbonate cells (MCFC/MCEC) as well as their association in a hybrid cell (HFC/HEC), making it possible to achieve high electrochemical performance, potentially reversible (FC/EC), at intermediate temperature. In addition, the interest for the ammonia vector, within the hydrogen sector, is presented.

The increase in longevity worldwide has intensified the use of different types of prostheses for the human body, such as those used in dental work as well as in hip and knee replacements. Currently, Ti-6Al-4V is widely used as a joint implant due to its good mechanical properties and durability. However, studies have revealed that this alloy can release metal ions or particles harmful to human health. The mechanisms are not well understood yet and may involve wear and/or corrosion. Therefore, in this work, commercial pure titanium and a Ti-6Al-4V alloy were investigated before and after being exposed to a simulated biological fluid through tribological tests, surface analysis, and ionic dissolution characterization by ICP-AES. Before exposure, X-ray diffraction and optical microscopy revealed equiaxed α-Ti in both materials and β-Ti in Ti-6Al-4V. Scratch tests exhibited a lower coefficient of friction for Ti-6Al-4V alloy than commercially pure titanium. After exposure, X-ray photoelectron spectroscopy and surface-enhanced Raman spectroscopy results showed an oxide film formed by TiO2, both in commercially pure titanium and in Ti-6Al-4V, and by TiO and Al2O3 associated with the presence of the alloys. Furthermore, inductively coupled plasma atomic emission spectroscopy revealed that aluminum was the main ion released for Ti-6Al-4V, giving negligible values for the other metal ions.

Due to a high conductivity of about 0.1 S·cm−1, Li-Na-K carbonate eutectic and Sm-doped ceria composite material is a good electrolyte candidate for hybrid fuel cells operating between 500 °C and 600 °C. The present paper aims at a deeper understanding of the species and mechanisms involved in the ionic transport through impedance spectroscopy and thermal analyses, in oxidizing and reducing atmospheres, wet and dry, and during two heating/cooling cycles. Complementary structural analyses of post-mortem phases allowed us to evidence the irreversible partial transformation of molten carbonates into hydrogenated species, when water and/or hydrogen are added in the surrounding atmospheres. Furthermore, this modification was avoided by adding CO2 in anodic and/or cathodic compartments. Finally, a mechanistic model of such composite electrical behavior is suggested, according to the surrounding atmospheres used. It leads to the conclusions that cells based on this kind of electrolyte would preferably operate in molten carbonate fuel cell conditions, than in solid oxide fuel cell conditions, and confirms the name of “Hybrid Fuel Cells” instead of Intermediate Temperature (or even Low Temperature) Solid Oxide Fuel Cells.

Driven by the increasing concern about the risk of diclofenac (DCF) residues as water pollutants in the aqueous environment and the growing need for its trace determination, a simple but sensitive electrochemical aptasensor for the trace detection of DCF was developed. To construct the aptasensor, the amine-terminated DCF aptamer was covalently immobilized on the surface of the carboxylic acid–functionalized multi-walled carbon nanotube (f-MWCNT)–modified glassy carbon electrode (GCE) through EDC/NHS chemistry. The f-MWCNTs provide a reliable matrix for aptamer immobilization with high grafting density, while the aptamer serves as a biorecognition probe for DCF. The obtained aptasensor was incubated with DCF solutions at different concentrations and was then investigated by electrochemical impedance spectroscopy (EIS). It displays two linear ranges of concentration for DCF detection, from 250 fM to 1pM and from 1 pM to 500 nM with an extremely low detection limit of 162 fM. Also, the developed biosensor shows great reproducibility, acceptable stability, and reliable selectivity. Therefore, it offers a simple but effective aptasensor construction strategy for trace detection of DCF and is anticipated to show great potential for environmental applications.

Due to their low melting point and high conductivity molten hydroxides are interesting electrolytes, or additive to other molten electrolytes for high-temperature electrochemical devices. There is nowadays a revival of such reactive media, first of all for their significant role in the electrode mechanisms in molten carbonate fuel cells (MCFCs) and the reverse co-electrolysis of water and carbon dioxide process, but also in different applications, among which direct carbon fuel cells (DCFCs), hybrid carbonate/oxide fuel cells. This overview shows the properties and interest of molten hydroxides and their use in relevant energy devices, pointing out their direct use as electrolytic media or as key species in complex kinetic processes. A thorough understanding of their behavior should allow improving and optimizing significantly fuel cells, electrolyzers, and probably also CO 2 capture and valorization.

Porous titanium materials have gained interest as prosthesis materials due to their similar mechanical properties to the human bone, biocompatibility, and high corrosion resistance. The presence of pores in the metal matrix implies a decrease in the elastic modulus and an increase in the active area, perhaps improving the osseointegration. Corrosion resistance is a critical consideration as corrosion may lead not only to mechanical failure but also the release of ions and/or particles to the bloodstream. In this work, a novel Ti-Nb-Ta-Fe-Mn alloy with varying percentage of porosity (25, 31 and 37 v/v%) was exposed to simulated body fluid (SBF) at 37 °C and its corrosion resistance was investigated using electrochemical techniques and surface analysis as a function of exposure time. Open circuit potential and polarization curves revealed that the effect of porosity was mainly on the shift of the corrosion potential to more negative values with a slight increase in the anodic current. A passive range was also observed, which was not influenced either by increased exposure time or increased porosity. Therefore, a change in the surface specific area could have taken place during the exposure, which is not necessarily related to a corrosion process. Moreover, a typical porous electrode behavior was identified by electrochemical Impedance spectroscopy, without any significant change over time. No release of metal ions was detected by on line ICP-AES, either at the open circuit potential or upon polarizing the samples up to 2 V vs. SCE, whereas only traces elements (Fe and Mn 1 nmol/s cm2) were detected in the electrolyte accumulating all released ions during 30 days of exposure. Additionally, the surface analysis showed thickening of the oxide layer with exposure time. Therefore, the stability of the passive layer and low release of ions indicate that the porous alloys are suitable for further study as prosthesis materials.

Ti-6Al-4V alloy has been widely investigated for biomedical applications due to its low density, high specific strength, and favorable corrosion resistance. However, some reported failures have imposed a challenge to improve bone regeneration and fixation, as well as antibacterial properties. A further opportunity for solving this problem is the introduction of porosity. However, this can induce metallic release and corrosion product formation. In this work, a Ti-6Al-4V alloy was exposed to Hank's solution, sterilized and inoculated with Staphylococcus aureus at 37 degrees C. Surface analysis was carried out by SEM-EDS and XPS. Electrochemical measurements were also performed using chronopotentiometry at open circuit potential, polarization curves, and electrochemical impedance spectroscopy. After exposure, FE-SEM showed some colonies of S. aureus on the sample with 22% porosity. However, XPS analysis revealed that the presence of bacterium influenced the composition of the oxide layer, even more drastically with the increase in added porosity. Moreover, the impedance analysis showed De Levie's behavior, revealing a reduction of pore resistance and modulus of the impedance in the low frequency range in inoculated medium, and polarization curves showed that the passivity potential range was decreased, whereas the passivity current increased in the presence of the S. aureus. (C) 2020 Elsevier B.V. All rights reserved.

A three-electrode electrochemical cell was used for the synthesis of ceria thin films in an aqueous nitrate media, using the electrogenerated base method. The choice of the precursor of hydroxide is important regarding the mechanisms involved and the morphology of the deposits. The current-time curves were analyzed for the estimation of the growth kinetics. The scanning electronic microscopy analyses showed that a needle-like shape is characteristic of the CeO2 thin films. For the thin films deposited within 20 and 60 min, the thickness was 336 nm and 1 mu m, respectively, confirming the linearity of the thickness with the deposition duration.

Crystalline rare‐earth (RE)‐doped Y2O3 films are an attractive system for a wide range of photonics applications including quantum technologies which aim at harnessing optical or spin transitions with long coherence times to achieve new functionalities such as quantum storage or information processing. Herein, atomic layer deposition (ALD) of Eu‐doped Y2O3 thin films with improved optical properties is presented. A crucial post‐treatment step to obtain high‐quality films is annealing at elevated temperatures (>900 °C). However, the main drawback of this approach is the formation of unwanted parasitic phases due to reaction at the interface with the substrate, especially with silicon. In this article, this issue is discussed for different kinds of substrates and buffer layers. The use of such modified substrates allows advantageously extending the maximum thermal treatment up to 1150 °C without being limited by interface reactions. It is demonstrated that the emission of the 5D0 → 7F2 transition for Eu3+ in Y2O3 film can be as narrow as that of bulk materials when optimized thermal treatments and a thin undoped Y2O3 buffer layer are used. Thus, a versatile method to reduce the impact of the substrate–film interface on the optical properties is proposed.

In this study, the electrochemical breakdown potentials (E b) of NiTi stents were assessed in correlation to their nonmetallic inclusion fractions in the extra low inclusion (ELI) range (inclu.% < 1% in area fraction, average size <39 μm). Quantitative investigations were performed to study the role of nonmetallic inclusions during pitting corrosion. Two stent samples with different inclusion fractions were fabricated using commercial NiTi tubes for studying the corrosion and mechanism. A survey of seven commercial stents in Europe was also conducted. Dependence was observed between the breakdown potentials and the inclusion fractions in the ELI stent (inclu.% = 0.2-0.8%), in which the breakdown potentials were found to be inversely proportional to inclusion fractions and densities (E b dropped from ∼800 to ∼400 mV). No breakdown occurred on the samples using high-purity NiTi materials (inclu.% < 0.1%). The roles of inclusions in pitting mechanisms were investigated using scanning electron microscopy (SEM) characterizations. The microstructural evidence showed that the impact of TiC and Ti2NiO x was very different in the pitting process. A maximum inclu.% ≤ 0.9% was required for obtaining E b ≥ 600 mV to meet the Food and Drug Administrations (FDA's) in vivo safety acceptance (low risk up to 6 months postimplantation). The high-purity stents (inclu.% < 0.1%) did not exhibit corrosion susceptibility until 1000 mV, suggesting superior corrosion resistance and thus long-term in vivo safety.

The SOFC/SOEC community is now convinced that it is necessary to reduce the operating temperature of fuel cells to make the systems more robust, more reliable and thus to consider large-scale development. At the material level, the change of the reference electrolyte (YSZ) by a cerium compounds allows a significant performance gain for lower temperatures of use. It is obviously necessary to keep in mind the constraints related to the electrolyte application in solid electrolyte device, namely: good ionic conductivity unlike the electrical conductivity which must be low, electrochemical compatibility with the electrodes, be dense and covering on porous substrates. In this study, Gadolinia doped ceria coatings were deposited by cathodic arc evaporation from a metallic Ce-Gd (90/10 at%) target inserted into a conventional multiarc Ti evaporation target in the presence of a reactive argon-oxygen gas mixture. The structural and chemical features of these films were determined by X-ray diffraction and scanning electron microscopy. Their electrical properties were characterised using impedance spectroscopy measurements. It is shown that the as-deposited coatings crystallise in the fluorite type fcc structure of ceria and that their composition is the same than that of the target. The morphology of the coatings is influenced by the evaporation parameter (stress and droplet). The electrical measurements showed two contributions in Nyquist representation (figure1) and the activation energy is slightly higher than that given in the literature data for the bulk material. Figure 1 : Nyquist impedance plots of GDC coating, registered at 400°C, for two a.c. signal amplitudes. Logarithms of frequencies are indicated in the figure. Figure 1

Atomic layer deposited (ALD) Y2O3 thin films have been thoroughly investigated for optical or electronic applications. The coherent spectroscopy of lanthanide ions doped into this material has also...

The accelerated degradation of a commercial LSCF/YDC/YSZ/Ni-YSZ solid oxide electrolyzer cell (La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3- δ /Y 0.1 CeO 1.95 /Y 0.08 Zr 0.92 O 1.96 /Ni-YSZ) contaminated by Si-containing impurities is studied with time under up to − 1.7 A cm −2 applied. Above ~ − 0.6 A cm −2 , a new region appears in the polarization curve. This region corresponds to electronic conduction in the yttria-stabilized zirconia (YSZ) electrolyte, induced by the reduction under high current conditions. A shift in the typical frequencies (relaxation times) toward lower frequencies is then observed for the entire impedance spectra. This shift results finally in the disappearance of the positive loop related to the polarization resistance and the appearance of a negative (inductance type) loop which crosses the real axis ( Z ’) at the lowest frequencies to become positive again. This is characteristic for an electrode process mode in which the electrochemical redox reactions vanish while the cell current becomes mainly electronic due to the reduction of the YSZ electrolyte. This trend increases with time. Such a characterization of the electronic conduction of the YSZ electrolyte by electrochemical impedance spectroscopy has not been reported to date under electrolysis mode, to the best of our knowledge. Post-mortem analysis by scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM/EDX) shows detrimental degradation of the electrolyte after only 360 h of overall testing duration with numerous micropores in the YSZ volume, and cracks and delamination at the yttria-doped ceria (YDC)/YSZ interface. EDX analysis reveals (i) a migration of La, Sr, Co, and Fe elements from lanthanum strontium cobalt ferrite (LSCF) anode to YDC layer and YSZ electrolyte and (ii) a very important shift of Ni from Ni-YSZ cathode to YSZ and YDC, and also to LSCF anode in a lower proportion. This study highlights the critical issue that impurities represent for solid oxide electrolysis cell operation.