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BackgroundSolid oxide electrolysis cell (SOEC) offers a promising method for converting H2O into H2 at high temperatures ranging from 600 °C to 850 °C. Glass sealants, which are crucial materials in SOEC, fulfill most criteria for an ideal sealant when appropriate glass components at suitable stoichiometric proportions are selected. Nevertheless, they exhibit certain drawbacks, including limited stability, elevated gas leakage rates, and suboptimal thermal cycling performance during the SOEC operation.PurposeThis study aims to evaluate the performance of Al2O3 added Ba-Si-Ca sealant for SOEC.MethodsFirstly, a new Ba-Si-Ca system sealing glass (glass-P) was developed to enhance its properties, such as the coefficient of thermal expansion, glass transition, and softening temperatures, and a series of alumina additions to glass-P, intended for use as the SOEC sealant, were prepared using curtain coating. Then, the coefficients of thermal expansion of these sealants were evaluated using a thermal expansion instrument. The leak rate of the sealants, as well as the impact of different alumina additives on the material's thermal shock resistance and chemical stability, were assessed via a 1-cell stack measurement for extended SOEC operation. Finally, the elemental distribution of the specimen was observed using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (EDS).ResultsThe experimental results show that the leakage rate of the glass P-10 sealant is measured at 5.54×10-3 sccm∙cm-1, which is lower than that of glass P. After undergoing ten thermal cycles, the leakage rate of glass P-10 is found to be 2.275×10-2 sccm∙cm-1, lower than that of the others. An open circuit voltage (OCV) of approximately 1.169 V is recorded for glass P-10 after a 1 053-h test.ConclusionsThe addition of alumina to glass P significantly enhances the sealant's thermal stability and gas tightness.

A simulated interconnect/contact/cathode/cathode support test cell is fabricated to investigate the effectiveness of the high‐entropy alloy as the contact material on the microstructure and the performance of the converted spinel‐based layer. Although the CuMnNiFeCo alloy powder is selected as the contact precursor, it showed good sinterability after sintering at 900°C for 2 h in air. The electrical performance of the contact layer is evaluated by the area‐specific resistance measurement, including isothermal exposure and thermal cycling. The compatibility of the contact layer with adjacent components is investigated through observing the cross‐sectional view of the test cell. Furthermore, the effectiveness of the contact layer in inhibiting Cr migration is also assessed. [ABSTRACT FROM AUTHOR]

High efficiency, raw material availability, and compatibility with downstream systems will enable the Solid Oxide Electrolysis Cell (SOEC) to play an important role in the future energy transition. However, the SOEC stack's performance should be improved further by utilizing a novel flow-field design, and the channel shape is a key factor for enhancing gas transportation. To investigate the main effects of the novel channel design with fewer calculations, we assumed ideal gas laminar flows in the cathode channel. Furthermore, the cathode support layer thickness and electrical contact resistance are ignored. The conventional channel flow is validated first with mesh independence, and then the performance difference between the conventional and novel designs is analyzed using COMSOL Multiphysics. The process parameters such as velocity, pressure, current density, and mole concentration are compared between the conventional and novel designs, demonstrating that the novel design significantly improves electrolysis efficiency. Furthermore, it directly increased the concentration of product hydrogen in the novel channel. In addition to enhancing convection and diffusion of reaction gases in neighboring channels, the simple structure makes it easy to manufacture, which is advantageous for accelerating commercial use of the novel design. [ABSTRACT FROM AUTHOR]

Molten salts have been reported to be excellent media for the preparation of multicationic oxides, which require harsh conditions to crystallize. Molten salt synthesis provides a wider operational temperature range (usually extends to 1000 °C) and faster mass transport and nucleation processes, thus allowing the preparation of crystalline solids, which require higher temperatures, such as perovskites. However, the mechanisms that control the solid-state formation and phase selection are poorly understood. Herein, several typical molten alkali metal halide (Cl−) and oxosalt (CO32− and SO42−) systems were employed as the reaction media for the synthesis of LaCoO3 (LCO) crystals, and the effects of ionic salt species on the morphological, geometric and electronic structures of LCO crystals were examined by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray absorption spectroscopy (XAS). The LCO perovskite was successfully synthesized in a molten NaCl–KCl eutectic mixture at 700 °C, which was lower than that used for the conventional mixed oxide synthesis. Our results show that in the molten salt synthesis, the type of reaction medium, calcination temperature, the ratio of salt, and reaction time govern the microscopic mechanisms in the preparation of multicationic oxides. Most importantly, we observed that LaOCl was formed as an intermediate, which plays a key role in the reaction pathway for the phase-selective synthesis of perovskite LCO. [ABSTRACT FROM AUTHOR]

The electrochemical reduction of CO2 is a promising route to convert waste products to valuable chemicals. Search for suitable and efficient CO2 reduction electrocatalysts with high C2:C1 selectivity holds great promise. Herein, for the first time we have developed a molten salt oxidized method to modify the morphology and oxidation state of a Cu‐foam catalyst. The catalyst displayed a current density of 30 mA cm−2 (−1.4 V versus reversible hydrogen electrode) and an ethylene/methane ratio of 870. We provide insight into the improved performance of the catalysts by cross section scanning transmission electron microscopy and quasi in situ soft X‐ray spectroscope, which show that copper oxides are surprisingly reconstructed with Cu (I) and Cu (0) on the surface during the reaction. First principle calculations also demonstrate that the partly reduced Cu2O (111) surface has a high reactivity and selectivity for C2+ products. Furthermore, the molten salt treated catalysts could be applied to the direct synthesis of multi‐carbon fuels, including C3‐C4 compounds in high CO2 pressure electrocatalytic reduction. Our results demonstrate that molten salt are both the oxidizing agent and reaction medium, which is a promising approach for synthesis of highly active CO2 electrocatalysts, which may open a new way for industrial application. [ABSTRACT FROM AUTHOR]