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291.
《International Journal of Hydrogen Energy》2023,48(40):15248-15257
A new honeycomb-shaped La0·5Sr0·5Fe0·9P0·1O3-δ (LSFP) material has been proposed as a cathode for proton-conducting solid oxide fuel cells (H–SOFCs). Compared with conventional LSFP, the honeycomb-shaped does not change the crystal structure or the electronic structure of the material but offers a much higher surface area. The unique honeycomb structure allows the easier diffusion of air and H2O evaporations in the cathode, thus benefiting the application of LSFP as a cathode for LSFP. The honeycomb LSFP cathode's fuel cell shows a peak power density of 1474 mW cm−2 at 700 °C, which is higher than the conventional LSFP cell. In addition, the fuel cell performance is also the highest ever reported for H–SOFCs based on the Sr-doped LaFeO3 (LSF) cathodes, making a new life for the first-generation LSF cathode for H–SOFCs. The distribution of relaxation times (DRT) analysis for the cell reveals that the honeycomb-shaped cathode improves the oxygen reduction reaction (ORR) at the cathode, thus improving the cathode kinetics. 相似文献
292.
《International Journal of Hydrogen Energy》2023,48(33):12168-12175
Oxidation behavior of porous P434L ferritic stainless steel, used for the fabrication of metal-supported solid oxide electrolysis cells (MS-SOEC), is studied under oxygen-side and steam-side conditions. The impact of oxygen content on the oxygen side and steam:hydrogen ratio on the steam side is determined at 700 °C for bare, as-sintered samples. For these conditions, oxidation is more aggressive in the steam-side atmosphere. Oxygen with 3% humidification and steam:hydrogen ratio of 90:10 are selected for further assessment with pre-oxidized, catalyst-coated, and CuMn1·8O4-coated samples. The rapid oxidation at 700 °C and breakaway oxidation at 600 °C observed for bare stainless steel in 90:10 steam:hydrogen is mitigated by pre-oxidizing the sample in air before exposure. In oxygen, addition of the catalyst or CuMn1·8O4 coatings moderately increases the oxidation rate, due to consumption of Cr via reaction between the coatings and Cr-oxide scale. The results for ex-situ controlled oxidation are similar to oxidation observed after 1000 h operation of a full MS-SOEC. In general, the oxidation behavior at 700 °C is found to be acceptable. 相似文献
293.
《International Journal of Hydrogen Energy》2023,48(35):12949-12957
Metal-supported solid oxide electrolysis cells (MS-SOECs) operating at 600–700 °C are attractive for storage of intermittent renewable electricity from solar and wind energy due to their advantages of easy sealing and fast startup. This paper reports on the fabrication of MS-SOECs consisting of dense scandium stabilized zirconia (SSZ) electrolytes, Ce0.8Sm0.2O2−δ (SDC)/Ni impregnated 430L/SSZ cathodes and SmBa0.5Sr0.5Co2O5+δ (SBSCO) impregnated SSZ anodes supported on porous 430L alloys. Such cells demonstrated excellent electrolysis performance with current densities at 650 °C as high as 0.73 A⋅cm−2 at 1.3 V in 50% H2O-50% H2 and 0.95 A⋅cm−2 at 1.5 V in 90% CO2-10% CO. Electrochemical impedance measurements indicated that the cell performance was largely limited by the ohmic losses for steam electrolysis and by the cathodic reduction reactions for CO2 electrolysis, especially at reduced temperatures. Pronounced degradation was observed for both steam and CO2 electrolysis over the preliminary 90-h stability measurements at 600 °C. SEM examination and EDS mapping of measured cells showed significant aggregation and coarsening of impregnated Ni particles, resulting in smaller activities for H2O and CO2 reduction reactions. As evidenced by the almost unaltered ohmic resistances over the measurement durations, the 430L stainless steel substrates demonstrate excellent resistances against corrosions from H2O and CO2 and thus show great promise for applications in reduced-temperature MS-SOECs. 相似文献
294.
《International Journal of Hydrogen Energy》2023,48(36):13633-13649
Polymer Electrolyte Membrane Fuel Cell (PEMFC) is a promising electricity-producing technology but needs further improvement to become economically viable. Oxygen transfer to reaction zone is known as one of the main PEMFC performance-limiting factors. Accordingly, various recent studies have been focused on fuel cell design to improve oxygen transfer. The present study numerically investigates the influences of converting a straight (or planar) PEMFC to a bent (arc-shaped) one. The idea of PEMFC bending originates from the fact that it can create a velocity component perpendicular to gas diffusion layer (GDL) and exert centrifugal force on channel gas flow towards the GDL; thereby, enhancing oxygen transfer. The results indicate that PEMFC bending can enhance performance up to about 8.33% for the examined operating conditions. It is also observed that PEMFC bending impact factor generally increases with operating pressure, stoichiometry ratio and bending angle, but decreases with operating voltage. 相似文献
295.
《Ceramics International》2023,49(16):26359-26368
Rare earth zirconates have incomparable chemical thermophysical properties, yet the difficulty of preparation methods limit their application as fibrous material. In present work, a spinnable La2Zr2O7 precursor, named as carboxylate lanthanum-zirconium (COLZ), was developed using carboxylic acids as structural and functional ligands. When COLZ is in its liquid state, it can be readily processed into desired shapes, allowing preparation of high aspect ratio precursor fibers with dense and bonding-strong internal structures. The spinnability was explained by the transformation from solid to liquid state under external forces, in which dynamic bridging of carboxylate and hydroxyl between nano-sized colloidal particles play a key role. Due to weakly acidic ligands, organics in COLZ can be easily removed, making direct heat treatment at the target temperature possible, which is beneficial for massive production. The strategy of developing spinnable precursor could also be applied to prepare other rare earth zirconate fibers or new multi-oxide fibers. 相似文献
296.
在长期进化过程中,自然界中的多种动物、植物形成了独特的轻质、高强结构,以此来抵抗外界的复杂冲击载荷,保护自身完整,满足生存需要。生物轻质高强结构的优越性,启发了科研和工程人员采用结构仿生学的方法来对管状和板状两大类吸能结构进行设计优化和改进。对竹子、茎秆/树干、羽轴、骨骼四类管状生物结构和甲虫鞘翅、贝壳、柚子皮、龟壳四类板状生物结构进行综述,阐述了分层、多孔、螺旋、中空等多种结构与轻质高强特性之间的关系。在此基础上,对比和分析了相应的结构元素在单胞管、多胞管、嵌套管、波纹管等管状吸能结构和蜂窝夹芯板、复合材料板、混合结构板等板状吸能机构中起到的作用。进一步对当前仿生吸能领域存在的结构复杂、质量大、缺乏普适性的机理和过渡“桥梁”等问题做出了分析;最后对仿生吸能技术的形式简单化、结构轻量化、理论通用化、“形神兼备”化发展趋势做出展望。 相似文献