Michel Cassir

École nationale supérieure de chimie de Paris · LECIME

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 an...

The matrix material in a Molten Carbonate Fuel Cell, usually LiAlO2, has an important role in the ionic conduction, gas sealing and electrolyte retention. To avoid cracking, this material has been reinforced with various additives, mostly Al-based, which are subject to in situ lithiation. In this work, matrices were systematically synthesized throu...

Co-electrolysis of water and carbon dioxide in molten carbonates is nowadays a key issue in MCEC (molten carbonate electrolysis cell) and, reversely, for a better understanding of MCFC (molten carbonate fuel cell). The products of water and carbon dioxide reduction are the fuels that might be used in MCFC or other energy devices. The present study...

Gadolinia doped ceria coatings were elaborated 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 micros...

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...

AISI 430 stainless steel is an attractive material to be used in the healthcare industry, particularly as a sensor due to its low cost, corrosion resistance, as well as being Ni-free. AISI 430 was evaluated in an artificial sweat solution with the presence of Escherichia coli, and Staphylococcus aureus. Surface microbial analyses did not reveal col...

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 temper...

CO2 plays a major role in the molten carbonate fuel cell (MCFC) and its reverse process, the molten carbonate electrolysis cell (MCEC), because of the capability of the mentioned electrolyte to capture big amounts of this greenhouse gas. In particular, the co-electrolysis process together with water, would ideally yield syngas (H2 + CO). The reduct...

In order to reduce carbon dioxide emission, one solution is to convert into valuable chemicals or fuels, e.g. transforming CO2 into CO by electrochemical reduction. Thus, this greenhouse gas could be re-used in particular as syngas (CO + H2) by co-electrolysis of CO2/H2O. High temperature electrolysis cells can be the best energetic devices to prod...

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 in...

As the capture and valorization of CO2 in molten carbonates is nowadays becoming a strategic energy topic, the need of accurate solubility measurements of such molecule is becoming compulsory. This study provides a new set of reliable CO2 solubility values, determined by a a carefully adapted manometric setup, in Li2CO3-K2CO3 (62:38 mol%), Li2CO3-N...

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. Corrosio...

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 like quantum storage or information processing. Here we present Atomic Layer Deposition (ALD) of...

In this work, PdFe2O3 bimetallic materials containing oxygen vacancies (Ov, from 10 to 75%) and two bimetallic nanoparticles based on noble metals (PdAu and PdPt) were obtained and evaluated for the ethanol electro‒oxidation reaction (EOR) in alkaline medium. For this purpose, bimetallic nanoparticles were synthesized keeping similar crystallite si...

This study is focused on the search of new electrolyte/cathode interface architecture for intermediate temperature solid oxide fuel cells (IT-SOFCs). India-doped zirconia (IDZ) thin multilayer with three different contents of indium oxide, allowing to pass from an ionic conductor (30 mol% of InO1.5) to an electronic one (80 mol% of InO1.5) are depo...

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 recently attracted an increasing interest in the field of quantum technologies for which they are considered as promising candidates in quantum memories...

Oxide-carbonate composite electrolytes are complex materials whose peculiar conductivity performances are yet to be fully understood. Stability issues however arise when the carbonate is combined to an oxide such as TiO2, preventing practical fuel cell application of TiO2-based composites. To investigate the origin of such instability, a combined e...

Sorbitol is a potentially cheap fuel that can be easily produced from biomass. However, despite its renewable character, the sorbitol electro-oxidation reaction (SOR) has been barely studied, being mostly analyzed using massive or nanoparticulate Pt-based materials, exhibiting poor activity. This work proposes the green synthesis of Au/C, Pd/C and...

The accelerated degradation of a commercial LSCF/YDC/YSZ/Ni-YSZ solid oxide electrolyzer cell (La0.6Sr0.4Co0.2Fe0.8O3-δ/Y0.1CeO1.95/Y0.08Zr0.92O1.96/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...

Degradation-related issues are among the main limitations to make solid oxide electrolysis cells (SOEC) meet performance targets economically viable for long-term operation. In this study, the considered cell presents a premature degradation during electrolysis operation observed after sealing the cell holder and the support pieces providing and re...

This paper is dedicated to the impact of pressure on the electrochemical behaviour of LSCF (La1-xSrxCoyFe1-yO3-δ) anode in high-temperature electrolysers. This study was carried out with symmetrical cells associating LSCF electrodes to a 3YSZ (yttrium-stabilised zirconia) electrolyte. Impedance spectroscopy measurements were performed using a three...

Small fiber peripheral neuropathy is an early complication of diabetes. Electric skin response to some stimulus, as electrochemical skin conductance ECS, is a promising route in the early follow‐up of such diseases. It is related to sweat gland innervations and their permeability to chlorides and protons; it is non‐invasive, quantitative and reprod...

This is an overview of the electrochemical characterization of nickel and stainless steel (so‐called SS) as electrodes in medical devices for the early diagnosis of small fiber neuropathy that originates from type‐2 diabetes or cystic fibrosis. The electrical current responses obtained during the clinical tests are related to the amount of chloride...

Adsorption of self-assembled monolayer (SAM) of different imidazolines derivatives was investigated on Fe2O3 (0 0 0 1) surface with DFT calculations to understand their corrosion inhibition mechanism. Quantum chemistry calculations enable us acquiring a better insight on the nature of imidazoline/surface interactions, i.e. partly covalent bonds, an...

A comprehensive density functional theory (DFT) investigation of conduction mechanisms of both intrinsic and extrinsic species found in oxide-carbonate composite electrolytes materials used in SOFC is presented. An interface model of YSZ-LiKCO3 is used as a case study to investigate transport properties, considering different mechanistic assumption...

In this work, La2NiO4+δ is used as cathode material for Intermediate temperature solid oxide fuel cells (IT-SOFC). Scanning electron microscopy, X-ray diffraction, and electrochemical impedance spectroscopy are used to investigate the effect of the presence of an ultrathin La2NiO4+δ layer (80 nm) deposited by dip-coating or sputtering at the interf...

AISI 304L is used in SudoscanTM technology (Impeto Medical Inc.) for the early diagnosis of small fiber neuropathy caused by type-2 diabetes or cystic fibrosis. In a recent paper, several substitute electrodes were analyzed, among which the biocompatible nickel-free AISI 430 appeared as an interesting material. In the present work, we compare in de...

In order to improve the electrochemical performances of the zinc-air cells, the material Nd1.98Sr0.02Ni0.99Co0.01O4 ± δ was prepared following the citrate method and used as cathode materials for alkaline room temperature fuel cells towards the oxygen reduction reaction (ORR). The microstructure and morphology before and after the ORR process were...

Room temperature ionic liquids (RTILs) attract much attention as a new type of environmentally benign electrolytes for Li-ion batteries due to their numerous interesting physicochemical properties. Here, in this paper, Li intercalation/deintercalation in presence of the N-butyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl) imide (PYR14TFSI) a...

The development routes to improve the performances of SOFCs are globally well identified and lead to shift the characteristic i/v curve towards higher potentials and current densities, an effect that is consistent with a lowering of the three overpotentials (activation, resistance and concentration). An increase of the Triple Phase Boundary (TPB) d...

Due to the problems with greenhouse gas emission, fossil fuels consumption and air pollution, solid oxide fuel cells (SOFC) are a promising power generation technology, because of its good efficiency and low emissions. The key challenge is to achieve a competitive balance between cost, efficiency and durability. The aim of this work is to develop c...

In the perovskite structures widely investigated and used as Solid Oxide Fuel Cells (SOFC) cathodes, oxygen reduction is mainly limited to the triple phase boundary (TPB), where oxygen (air), electrode and electrolyte are in contact. It is possible via the sol-gel modified Pechini method to: 1) control the material grain size, which can increase TP...

The oxygen reduction reaction (ORR) was investigated using two new cathode materials based on neodymium nickelate with formula Nd2-xSrxNi1-yCoyO4±δ (with x and y=0 or 0.05) prepared by the citrate method. The ORR was measured in 0.5M NaOH with a rotating disk electrode (RDE) at different rotation speeds after purging with pure oxygen. The synthesiz...

High-purity-doped ceria compounds Ce1-xRExO2-δ (RE = Sm, Gd; 0 ≤ x ≤ 0.30) were synthesized by the Pechini method at 400 °C. Nanostructured products of crystallite size 5–11 nm were obtained, presenting a single fluorite cubic phase and high surface area values in the range of 75–110 m²g⁻¹. Dense ceramic products with a relative density of 96–98 %...

Carbon capture and valorization is a new route increasingly discussed to reduce greenhouse gas emissions. One of the paths foreseen for CO2 valorization is its transformation into fuels by electrochemical reduction of carbon dioxide. In this approach, molten carbonates are of particular interest since they can be used to capture CO2 molecule becaus...

This chapter is dedicated to the unique fuel cell using a molten salt electrolyte, the molten carbonate fuel cell (MCFC). This generator device operating at 650 °C has produced more power in the last 3 years (250 MW) than any other fuel cell. Our aim is to describe briefly the principles, including a focus on electrode reactions, and configuration...

Correction for ‘Modeling composite electrolytes for low-temperature solid oxide fuel cell application: structural, vibrational and electronic features of carbonate–oxide interfaces’ by Chiara Ricca et al., J. Mater. Chem. A, 2016, DOI: 10.1039/c6ta06827h.

We present a combined experimental and theoretical investigation of the YSZ-LiKCO3 composite, as an electrolyte alternative for low-temperature solid oxide fuel cells (LT-SOFC). Insights on its structure, stability, and electronic and vibrational properties are presented and discussed. The large adhesion energy computed (3.19 eV) indicates a strong...

Improvement of the molten carbonate fuel cell electrolyte is a key parameter to increase the performance of such electrochemical generator. One of the main challenges is to enhance the global oxygen reduction at the state-of-the-art porous nickel cathode. In this study, the effect of adding 5 mol% of caesium in Li[single bond]K and Li[single bond]N...

In a changing world, the paradigm of energy and environment is also evolving and the importance of hydrogen and fuel cells is progressively increasing. This evolution is slow but sure because fuel cells play already an important role in a transition phase, where fossil fuels are still predominant, and also for the future where renewable energies wi...

The electrochemical transformation of CO2 into more valuable chemicals such as CO offers great interest in the energetic field. In this paper, the feasibility of this valorisation process is investigated by cyclic voltammetry in different binary molten carbonates: Li2CO3 Na2CO3 (52:48 mol. %), Li2CO3 K2CO3 (62:38 mol. %) and Na2CO3 K2CO3 (56:44 mol...

Carbonate/oxide composites are very promising electrolyte materials in hybrid fuel cells which could operate at lower temperature than the usual Molten Carbonate Fuel Cells (MCFC) or Solid Oxide Fuel Cells (SOFC), presenting 0.1 S cm(-1) at 600 degrees C. This paper shows some significant and/or unexpected experimental data obtained by impedance sp...

Among promising applications, LiKCO3 can be used as component of the oxide-carbonate electrolytes for low temperature solid oxide fuel cells (LT-SOFCs), but the species ensuring the transport at the interface between the two phases is still undetermined. In view of better clarifying the role of the carbonate phase in these materials, we studied the...

This study addresses the problem of the nickel cathode dissolution, decreasing the lifetime of molten carbonate fuel cells, by a protective coating of Nb2O5 processed by atomic layer deposition ALD onto the porous cathode substrate. Samples of different thicknesses were tested electrochemically in molten Li2CO3-K2CO3 eutectic at 650 °C during 230 h...

Phases constituted by La2-xCuxNiO4±δ (0.01 ≤ x ≤ 0.1) of the Ruddlesden-Popper family (Lan+1NinO3n+1; n = 1) were prepared and then mixed with La4Ni3O10, in a weight ratio of 50:50 wt%, in order to be used as solid oxide fuel cell cathodes. ASR values relative to the symmetrical cells constituted by yttria-stabilized zirconia electrolyte and the fo...

The structural, electronic and surface properties of the mixed lithium-sodium (LiNaCO3) and lithium-potassium (LiKCO3) carbonates were studied through periodic calculations performed at the density functional theory (DFT) level, using three different exchange-correlation functionals. The hybrid functional PBE0 was found to be the best one to descri...

Atomic layer deposition (ALD) offers the opportunity to design and engineer surface structures at the atomic scale, targeting improved performance of not only fuel cells but also electrochemical sensors, electrolyzers, and pumps. Two types of high-temperature fuel cells, operating between 600 and 1000 °C, are developed: molten carbonate fuel cells...

The capture and utilization of CO2 is becoming progressively one of the significant challenges in the field of energetic resources. Whatever the energetic device, it is impossible to avoid completely the production of greenhouse gas, even parting from renewable energies. Transforming CO2 into a valuable fuel, such as alcohols, CO, or even C, could...

Optimization of the molten carbonate electrolyte is the most challenging topic in order to increase the lifetime and performance of the molten carbonate fuel cell (MCFC). Besides controlling electrolyte properties such as stability, conductivity, volatility, surface tension, molar volumes etc., it is mandatory to reduce the dissolution of the LixNi...

A non-invasive device based on measurements of electrochemical skin conductance can detect small fiber neuropathy, a sweat gland dysfunction implicated in several diseases. The measurement is related to sweat composition and notably to chloride concentration. To optimize the electrode material, in vitro experiments are performed in mimetic sweat so...

Increasing the performance of SOFC is many-fold: i/at low current density, through the enhancement of the catalytic properties of the electrodes; ii/in the ohmic loss region, through lower resistance; iii/in the high current density region, via the optimization of the electrodes microstructure. The present work proposes to explore how the corrugati...

In view of increasing SOFCs lifetime, lowering the working temperature is probably the most convenient solution. The targeted range is 400-600°C, low enough to minimize the degradation kinetics while keeping rather good electrochemical performance. Carbonate/oxide composites are promising materials as electrolyte in hybrid fuel cells, which could o...

Electrochemical Impedance Spectroscopy (EIS) is used here in a two-electrode configuration to acquire a deeper comprehension of high-temperature solid oxide electrolysis cells (SOEC), distinguishing different phenomena related to electrochemical and degradation processes. Such approach is applicable to any kind of electrochemical cell. In the prese...

The route for the increase in SOFC performances is many-fold: i/ in the low current density domain, through the enhancement of the catalytic properties of the electrodes, i.e. via a higher Triple Phase Boundary (TPB) density, hence a higher exchange current and a lower activation overpotential, ii/ in the ohmic loss region, through lower resistance...

In view of increasing the lifetime of high temperature fuel cells, lowering the working temperature is probably the most convenient solution. The targeted temperature range is 400-600°C, low enough to minimize the degradations kinetics while keeping rather good electrochemical performances and good conversion efficiencies. Carbonate/oxide composite...

Our world is facing energy needs always growing, the mid-term disappearance of important energy resources such as fossil fuels and global warming issues consecutive to massive greenhouse gas production. A possible answer to produce renewable and clean energy consists in combining promising technologies such as solar photovoltaic, wind turbine and f...

The surface chemistry is one of the most important factor influencing the electrochemical performance of LiBs. The modification of the chemical composition of electrode materials is related to formation of a passive layer, named as a Solid Electrolyte Interphase (SEI) layer ¹ , due to decomposition of electrolyte mostly during the first cycle of ch...

In order to improve the industrial attractiveness of high temperature steam electrolysis (HTSE), increasing the operating pressure is one of the most promising solutions. In this context, this study is dedicated to the analysis of the pressure influence on the electrochemical reactions occurring in HTSE. The behavior of half-cells constituted by YS...

Small fiber neuropathy is a dysfunction caused by diseases such as type II diabetes and cystic fibrosis. Nowadays, it is possible to analyze neuropathy with Sudoscan TM technology (Impeto Medical Inc.) which provides a rapid and non-invasive early diagnosis. This technology is based on measurements of the electrochemical conductance of the skin via...

Thin ceria layers of 120 nm were processed by atomic layer deposition on both YSZ(100) single crystal substrates and polycrystalline YSZ ones. The CeO2 layer deposited on the oriented substrate proved to be epitaxial after a low temperature annealing used to remove some crystallisation defects. The quality of the film was characterized by scanning...

Perovskite-type structures with the composition LaNixCo1−xO3 (x=0.3, 0.5, 0.7) were synthesized by a modified sol-gel method. Using transitional metal elements on the lanthanum base perovskites, properties could be tuned by doping the structure. Thermogravimetric analysis (TGA) evidenced a temperature of 350 °C as the start point of the perovskite-...

A detailed theoretical study concerning the formation of oxygen vacancies on the clean (111) surface of cubic ZrO2 and the structural and electronic properties of the (111) surface of yttria-stabilized zirconia (YSZ, 8 mol% Y2O3) was carried out using DFT methods in a periodic approach. For the formation of oxygen defects on the clean (111) surface...

During the past decade, the number of terrorism acts has increased and the need for efficient explosive detectors has become an urgent worldwide necessity. A prototype, Nebulex™, was recently developed in our laboratory. Basically, it couples the solubilization of an analyte from the atmosphere by a nebulization process and in-situ detection. This...

The bulk structure, the relative stability, and the electronic properties of monoclinic, tetragonal, and cubic ZrO2 have been studied from a theoretical point of view, through periodic ab initio calculations using different Gaussian basis sets together with Hartree–Fock (HF), pure Density Functional Theory (DFT), and mixed HF/DFT schemes as found i...

Understanding the electrode processes occurring at the electrode/electrolyte interface and in the bulk electrode material is necessary for developing the electrochemical performances of lithium-ion (LIB), sodium-ion, sulfur or metal-air batteries. The main electrode processes are insertion/extraction reactions that induce changes in the host electr...

In the world of alternative energy sources, the Molten Carbonate Fuel Cell (MCFC) is one of the promising technologies for the efficient conversion of hydrogen or hydrocarbons to power and heat. One of the main issues for optimizing this device is the control of the dissolution of the state-of-the-art porous nickel oxide cathode. A protective coati...