Research

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12 pages, 3641 KiB

Open AccessArticle

Photoelectrochemical Hydrogen Production System Using Li-Conductive Ceramic Membrane

by Ihor A. Rusetskyi, Leonid L. Kovalenko, Michail O. Danilov, Ivan A. Slobodyanyuk, Sergii S. Fomanyuk, Vitaliy O. Smilyk, Anatolii G. Belous and Gennadii Ya. Kolbasov

Membranes 2022, 12(12), 1189; https://doi.org/10.3390/membranes12121189 - 25 Nov 2022

Cited by 2 | Viewed by 972

Abstract

Based on the LiLaTiO₃ compound, a ceramic membrane for a photoelectrochemical cell was created. The microstructure, phase composition, and conductivity of a semiconductor photoelectrode and a ceramic membrane were studied by using various experimental methods of analysis. A ceramic Li conducting membrane [...] Read more.

Based on the LiLaTiO₃ compound, a ceramic membrane for a photoelectrochemical cell was created. The microstructure, phase composition, and conductivity of a semiconductor photoelectrode and a ceramic membrane were studied by using various experimental methods of analysis. A ceramic Li conducting membrane that consisted of Li_0.56La_0.33TiO₃ was investigated in solutions with different pH values. The fundamental possibility of creating a photoelectrochemical cell while using this membrane was shown. It was found that the lithium-conductive membrane effectively works in the photoelectrochemical system for hydrogen evolution and showed a good separating ability. When using a ceramic membrane, the pH in the cathode and anode chambers of the cell was stable during 3 months of testing. The complex impedance method was used to study the conductive ceramic membrane in a cell with separated cathode and anode chambers at different pH values of the electrolyte. The ceramic membrane shows promise for use in photoelectrochemical systems, provided that its resistivity is reduced (due to an increase in area and a decrease in thickness). Full article

(This article belongs to the Special Issue Ceramic Membranes for Fuel Cell Applications and Hydrogen Production)

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18 pages, 5628 KiB

Open AccessArticle

Processing Ceramic Proton Conductor Membranes for Use in Steam Electrolysis

by Kwati Leonard, Wendelin Deibert, Mariya E. Ivanova, Wilhelm A. Meulenberg, Tatsumi Ishihara and Hiroshige Matsumoto

Membranes 2020, 10(11), 339; https://doi.org/10.3390/membranes10110339 - 12 Nov 2020

Cited by 19 | Viewed by 3685

Abstract

Steam electrolysis constitutes a prospective technology for industrial-scale hydrogen production. The use of ceramic proton-conducting electrolytes is a beneficial option for lowering the operating temperature. However, a significant challenge with this type of electrolyte has been upscaling robust planar type devices. The fabrication [...] Read more.

Steam electrolysis constitutes a prospective technology for industrial-scale hydrogen production. The use of ceramic proton-conducting electrolytes is a beneficial option for lowering the operating temperature. However, a significant challenge with this type of electrolyte has been upscaling robust planar type devices. The fabrication of such multi-layered devices, usually via a tape casting process, requires careful control of individual layers’ shrinkages to prevent warping and cracks during sintering. The present work highlights the successful processing of 50 × 50 mm² planar electrode-supported barium cerium yttrium zirconate BaZr_0.44Ce_0.36Y_0.2O_2.9 (BZCY(54)_8/92) half cells via a sequential tape casting approach. The sintering parameters of the half-cells were analyzed and adjusted to obtain defect-free half-cells with diminished warping. Suitably dense and gas-tight electrolyte layers are obtained after co-sintering at 1350 °C for 5 h. We then assembled an electrolysis cell using Ba_0.5La_0.5CoO_3−δ as the steam electrode, screen printed on the electrolyte layer, and fired at 800 °C. A typical Ba_0.5La_0.5CoO_3−δ|BaZr_0.44Ce_0.36Y_0.2O_3−δ(15 μm)|NiO-SrZr_0.5Ce_0.4Y_0.1O_3−δ cell at 600 °C with 80% steam in the anode compartment reached reproducible terminal voltages of 1.4 V @ 500 mA·cm⁻², achieving ~84% Faradaic efficiency. Besides electrochemical characterization, the morphology and microstructure of the layered half-cells were analyzed by a combination of high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and energy-dispersive X-ray spectroscopy. Our results also provide a feasible approach for realizing the low-cost fabrication of large-sized protonic ceramic conducting electrolysis cells (PCECs). Full article

(This article belongs to the Special Issue Ceramic Membranes for Fuel Cell Applications and Hydrogen Production)

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17 pages, 5452 KiB

Open AccessArticle

A Novel Laser 3D Printing Method for the Advanced Manufacturing of Protonic Ceramics

by Shenglong Mu, Yuzhe Hong, Hua Huang, Akihiro Ishii, Jincheng Lei, Yang Song, Yanjun Li, Kyle S. Brinkman, Fei Peng, Hai Xiao and Jianhua Tong

Membranes 2020, 10(5), 98; https://doi.org/10.3390/membranes10050098 - 12 May 2020

Cited by 16 | Viewed by 4265

Abstract

Protonic ceramics (PCs) with high proton conductivity at intermediate temperatures (300–600 °C) have attracted many applications in energy conversion and storage devices such as PC fuel/electrolysis cells, PC membrane reactors, hydrogen pump, hydrogen or water-permeable membranes, and gas sensors. One of the essential [...] Read more.

Protonic ceramics (PCs) with high proton conductivity at intermediate temperatures (300–600 °C) have attracted many applications in energy conversion and storage devices such as PC fuel/electrolysis cells, PC membrane reactors, hydrogen pump, hydrogen or water-permeable membranes, and gas sensors. One of the essential steps for fulfilling the practical utilization of these intermediate-temperature PC energy devices is the successful development of advanced manufacturing methods for cost-effectively and rapidly fabricating them with high energy density and efficiency in a customized demand. In this work, we developed a new laser 3D printing (L3DP) technique by integrating digital microextrusion-based 3D printing and precise and rapid laser processing (sintering, drying, cutting, and polishing), which showed the capability of manufacturing PCs with desired complex geometries, crystal structures, and microstructures. The L3DP method allowed the fabrication of PC parts such as pellets, cylinders, cones, films, straight/lobed tubes with sealed endings, microchannel membranes, and half cells for assembling PC energy devices. The preliminary measurement of the L3DP electrolyte film showed a high proton conductivity of ≈7 × 10⁻³ S/cm. This L3DP technique not only demonstrated the potential to bring the PCs into practical use but also made it possible for the rapid direct digital manufacturing of ceramic-based devices. Full article

(This article belongs to the Special Issue Ceramic Membranes for Fuel Cell Applications and Hydrogen Production)

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23 pages, 4887 KiB

Open AccessArticle

Inkjet Printed Y-Substituted Barium Zirconate Layers as Electrolyte Membrane for Thin Film Electrochemical Devices

by Theodor Schneller and David Griesche

Membranes 2019, 9(10), 131; https://doi.org/10.3390/membranes9100131 - 11 Oct 2019

Cited by 3 | Viewed by 3001

Abstract

In this work, the inkjet printing of proton conducting Y-substituted barium zirconate (BZY) thin films was studied. Two different kinds of precursor inks, namely a rather molecular BZY precursor solution and a BZY nanoparticle dispersion, have been synthesized and initially investigated with regard [...] Read more.

In this work, the inkjet printing of proton conducting Y-substituted barium zirconate (BZY) thin films was studied. Two different kinds of precursor inks, namely a rather molecular BZY precursor solution and a BZY nanoparticle dispersion, have been synthesized and initially investigated with regard to their decomposition and phase formation behavior by thermal analysis, X-ray diffraction, and scanning electron microscopy. Their wetting behavior and rheological properties have been determined in order to evaluate their fundamental suitability for the inkjet process. Crystalline films have been already obtained at 700 °C, which is significantly lower compared to conventional solid-state synthesis. Increasing the temperature up to 1000 °C results in higher crystal quality. Permittivity measurements gave values of around 36 that are in good agreement with the literature while also proving the integrity of the materials. A modification of the as-synthesized BZY stock solution and nanoparticle dispersion by dilution with propionic acid improved the jetability of both inks and yielded homogeneous BZY coatings from both inks. In order to study the electrochemical properties of BZY films derived from the two printed inks, BZY coatings on sapphire substrates were prepared and characterized by electrochemical impedance spectroscopy. Full article

(This article belongs to the Special Issue Ceramic Membranes for Fuel Cell Applications and Hydrogen Production)

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12 pages, 4421 KiB

Open AccessArticle

Channelized Substrates Made from BaZr_0.75Ce_0.05Y_0.2O_3−d Proton-Conducting Ceramic Polymer Clay

by Sandrine Ricote, Benjamin L. Kee and W. Grover Coors

Membranes 2019, 9(10), 130; https://doi.org/10.3390/membranes9100130 - 09 Oct 2019

Cited by 3 | Viewed by 2447

Abstract

A novel process for producing thick protonic ceramics for use in hydrogen separation membrane reactors is demonstrated. Polymer clay bodies based on polyvinyl acetate (PVA) and mineral oil were formulated, and they permitted parts with complex architectures to be prepared by simple, low-pressure [...] Read more.

A novel process for producing thick protonic ceramics for use in hydrogen separation membrane reactors is demonstrated. Polymer clay bodies based on polyvinyl acetate (PVA) and mineral oil were formulated, and they permitted parts with complex architectures to be prepared by simple, low-pressure molding in the unfired, “green” state. Ceramic proton conductors based on doped barium zirconate/cerate, made by solid-state reactive sintering, are particularly well-suited for the polymer clay process. In this work, the ceramic proton conductor, BZCY755 (BaZr_0.75Ce_0.05Y_0.2O_3−d) was fabricated into a variety of shapes and sizes. Test coupons were produced to confirm that the polymer clay route leads to a high-quality ceramic material suitable for the demanding environment of high-temperature membrane reactors. It has been demonstrated that protonic ceramic specimens with the requisite properties are easily prepared at the laboratory scale. The polymer clay fabrication route opens up the possibility of high-volume, low-cost manufacturing at a commercial scale, by a process similar to how dinnerware and sanitary porcelain are produced today. Full article

(This article belongs to the Special Issue Ceramic Membranes for Fuel Cell Applications and Hydrogen Production)

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16 pages, 6604 KiB

Open AccessArticle

Factors Limiting the Apparent Hydrogen Flux in Asymmetric Tubular Cercer Membranes Based on La₂₇W_3.5Mo_1.5O_55.5−δ and La_0.87Sr_0.13CrO_3−δ

by Zuoan Li, Jonathan M. Polfus, Wen Xing, Christelle Denonville, Marie-Laure Fontaine and Rune Bredesen

Membranes 2019, 9(10), 126; https://doi.org/10.3390/membranes9100126 - 24 Sep 2019

Viewed by 2857

Abstract

Asymmetric tubular ceramic–ceramic (cercer) membranes based on La₂₇W_3.5Mo_1.5O_55.5−δ-La_0.87Sr_0.13CrO_3−δ were fabricated by a two-step firing method making use of water-based extrusion and dip-coating. The performance of the membranes was [...] Read more.

Asymmetric tubular ceramic–ceramic (cercer) membranes based on La₂₇W_3.5Mo_1.5O_55.5−δ-La_0.87Sr_0.13CrO_3−δ were fabricated by a two-step firing method making use of water-based extrusion and dip-coating. The performance of the membranes was characterized by measuring the hydrogen permeation flux and water splitting with dry and wet sweep gases, respectively. To explore the limiting factors for hydrogen and oxygen transport in the asymmetric membrane architecture, the effect of different gas flows and switching the feed and sweep sides of the membrane on the apparent hydrogen permeability was investigated. A dusty gas model was used to simulate the gas gradient inside the porous support, which was combined with Wagner diffusion calculations of the dense membrane layer to assess the overall transport across the asymmetric membrane. In addition, the stability of the membrane was investigated by means of flux measurements over a period of 400 h. Full article

(This article belongs to the Special Issue Ceramic Membranes for Fuel Cell Applications and Hydrogen Production)

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11 pages, 4006 KiB

Open AccessArticle

Thermoelectric Behavior of BaZr_0.9Y_0.1O_3−d Proton Conducting Electrolyte

by Dmitry Tsvetkov, Ivan Ivanov, Dmitry Malyshkin, Vladimir Sereda and Andrey Zuev

Membranes 2019, 9(9), 120; https://doi.org/10.3390/membranes9090120 - 13 Sep 2019

Cited by 9 | Viewed by 2801

Abstract

BaZr_0.9Y_0.1O_3-δ (BZY10), a promising proton conducting material, exhibits p-type conduction under oxidative conditions. Holes in BZY10 are of the small polaron type. However, there is no clear understanding at which places in the lattice they are localized. The [...] Read more.

BaZr_0.9Y_0.1O_3-δ (BZY10), a promising proton conducting material, exhibits p-type conduction under oxidative conditions. Holes in BZY10 are of the small polaron type. However, there is no clear understanding at which places in the lattice they are localized. The main objectives of this work were, therefore, to discuss the nature of electronic defects in BZY10 on the basis of the combined measurements of the thermo-EMF and conductivity. Total electrical conductivity and Seebeck coefficient of BZY10 were simultaneously studied depending on partial pressures of oxygen (pO₂), water (pH₂O) and temperature (T). The model equation for total conductivity and Seebeck coefficient derived on the basis of the proposed defect chemical approach was successfully fitted to the experimental data. Transference numbers of all the charge carriers in BZY10 were calculated. The heat of transport of oxide ions was found to be about one half the activation energy of their mobility, while that of protons was almost equal to the activation energy of their mobility. The results of the Seebeck coefficient modeling indicate that cation impurities, rather than oxygen sites, should be considered as a place of hole localization. Full article

(This article belongs to the Special Issue Ceramic Membranes for Fuel Cell Applications and Hydrogen Production)

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12 pages, 5184 KiB

Open AccessArticle

Correlation between Concentrations of Ni and Y in Y-Doped BaZrO₃ Electrolyte in Co-Sintered Cells: A Case of Controlled NiO Activity by Using MgO-NiO Solid Solution as Anode Substrate

by Donglin Han, Kenji Kuno and Tetsuya Uda

Membranes 2019, 9(8), 95; https://doi.org/10.3390/membranes9080095 - 02 Aug 2019

Cited by 10 | Viewed by 3343

Abstract

BaZr_0.8Y_0.2O_3-δ (BZY20) is promising to be applied as an electrolyte in fuel cells, electrolysis cells, etc. However, when a half cell composed of a BZY20 electrolyte layer and a BZY20-NiO composite anode substrate is co-sintered (1400–1600 °C), Ni [...] Read more.

BaZr_0.8Y_0.2O_3-δ (BZY20) is promising to be applied as an electrolyte in fuel cells, electrolysis cells, etc. However, when a half cell composed of a BZY20 electrolyte layer and a BZY20-NiO composite anode substrate is co-sintered (1400–1600 °C), Ni diffuses from the anode substrate into the electrolyte layer. Y content in the electrolyte layer decreases dramatically, since BZY20 cannot be equilibrated with NiO at such high temperature. Such Ni diffusion and Y loss are detrimental to the electrochemical performance of the electrolyte layer. In this work, we added MgO-NiO solid solution into the anode substrate to adjust the NiO activity (a_NiO) during the co-sintering process, and used three different co-sintering methods to control the BaO activity (a_BaO). The results revealed that by decreasing a_NiO in the system, the as-co-sintered electrolyte layer had the composition shifting towards the direction of high Y and low Ni cation ratios. A clear correlation between the intra-grain concentration of Ni and Y was confirmed. In other words, to prepare the electrolyte with the same Y cation ratio, the Ni diffusion into the electrolyte layer can be suppressed by using the MgO-NiO solid solution with a high MgO ratio and a low Ni ratio. Moreover, by increasing a_BaO, we found that the Y cation ratio increased and approached the nominal value of the pristine BZY20, when Mg_1−xNi_xO (x = 0.3 and 0.5) was used. In summary, both a_NiO and a_BaO play important roles in governing the composition of the electrolyte layer prepared by the co-sintering process. To evaluate the quality of the electrolyte layer, both the intra-grain Y and Ni concentrations should be carefully checked. Full article

(This article belongs to the Special Issue Ceramic Membranes for Fuel Cell Applications and Hydrogen Production)

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Review

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17 pages, 3528 KiB

Open AccessReview

Electrochemical Synthesis of Ammonia: Recent Efforts and Future Outlook

by Ioannis Garagounis, Anastasios Vourros, Demetrios Stoukides, Dionisios Dasopoulos and Michael Stoukides

Membranes 2019, 9(9), 112; https://doi.org/10.3390/membranes9090112 - 30 Aug 2019

Cited by 41 | Viewed by 8275

Abstract

Ammonia is a key chemical produced in huge quantities worldwide. Its primary industrial production is via the Haber-Bosch method; a process requiring high temperatures and pressures, and consuming large amounts of energy. In the past two decades, several alternatives to the existing process [...] Read more.

Ammonia is a key chemical produced in huge quantities worldwide. Its primary industrial production is via the Haber-Bosch method; a process requiring high temperatures and pressures, and consuming large amounts of energy. In the past two decades, several alternatives to the existing process have been proposed, including the electrochemical synthesis. The present paper reviews literature concerning this approach and the experimental research carried out in aqueous, molten salt, or solid electrolyte cells, over the past three years. The electrochemical systems are grouped, described, and discussed according to the operating temperature, which is determined by the electrolyte used, and their performance is valuated. The problems which need to be addressed further in order to scale-up the electrochemical synthesis of ammonia to the industrial level are examined. Full article

(This article belongs to the Special Issue Ceramic Membranes for Fuel Cell Applications and Hydrogen Production)

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