The quasi-perpetual electricity generating device based on ceramic fuel cell for closed systems

The features of ceramic fuel cells developed in Ukraine are discussed and their  application for production of hydrogen and oxygen in a closed loop device combining ceramic fuel cells (CFC) and ceramic  electrolyser cells (CEC)  is  considered.  High-temperature electrolysis  is profitable for production of hydrogen and oxygen from hot water steam, that is outcoming gas of CFC’s reactions and released traditionally in environment, as it is demonstrated theoretically

Joint Impedance Spectroscopy and Fractography Data Analysis of Ceria Doped Scandia Stabilized Zirconia Solid Electrolyte modified by powder types and sintering temperature

Parameters of the non-Debye relaxation in the 10Sc1CeSZ solid electrolyte made of various types of ZrO2 powder stabilized with 10-mol.% Sc2O3 and 1-mol.% CeO2 were studied. The influence of powder properties and their sintering temperatures on the impedance spectra is analyzed. In regard to electrical response, the polycrystalline ceramic electrolytes may be considered as a single-phase or a two-phase material consisting of a grain bulk and a boundary. In many cases, the boundary resistance is independent practically on dopants and their distribution across the powders and sintering temperatures. The powder compositions suitable for an electrolyte and electrodes are specified

Zirconium Oxide Stabilized By Scandium (III) And Cerium (IV) Complex Oxides As The Basis For Preparation Of Thick Films And Multilayers Structures For Low Temperature (600 °C) Fuel Cell

Weakly agglomerated zirconium dioxide nanopowders stabilized by complex oxides of scandium (III) and cerium (IV) were synthesized by precipitation from aqueous solutions. Using weakly agglomerated nanopowders, thick films were prepared by tape casting on a-Al2O3 substrates. These thick films have high oxygen conductivity; and their electron conductivity is lower than oxygen conductivity by 4 orders of magnitude. A multilayer system consisting of films of polycrystalline porous anode and solid electrolyte was prepared. The diffusion of cations in the anode boundary layer and change in the chemical composition of the electrolyte film are not observed at optimum synthesis conditions

Influence of reduction conditions of NiO on its mechanical and electrical properties

Yttria stabilized zirconia with a nickel catalyst (Ni-YSZ) is the most developed, widely used cermet anode for manufacturing Solid Oxide Fuel Cells (SOFCs). Its electro-catalytic properties, mechanical durability and performance stability in hydrogen-rich environments makes it the state of the art fuel electrode for SOFCs. During the reduction stage in initial SOFC operation, the virgin anode material, a NiO-YSZ mixture, is reduced to Ni-YSZ. The volume decrease associated with the change from NiO-YSZ to Ni-YSZ creates voids and causes structural changes, which can influence the physical properties of the anode. In this work, the structural, mechanical and electrical properties of NiO samples before and after reduction in pure H2 and a mixture of 5 vol. % H2-Ar were studied. The NiO to Ni phase transformations that occur in the anode under reducing and Reduction-Oxidation (RedOx) cycling conditions and the impact on cell microstruc-ture, strength and electrical conductivity have been examined. Results show that the RedOx treatment of the NiO samples influence on their properties controversially, due to structural transformation (formation of large amount of fine pores) of the reduced Ni. It strengthened the treated samples yielding the highest mechanical strength values of 25.7 MPa, but from another side it is resulting in lowest electrical conductivity value of 1.9×105 S m-1 among all reduced samples. The results of this investigation shows that reduction conditions of NiO is a powerful tool for influence on properties of the anode substrate

Behaviour of Solid Oxide Fuel Cell Materials in Technological Environments

The YSZ–NiO ceramics for SOFC anodes and MAX-phases of Ti-Al-C systems for interconnects have been investigated. Based on the tests of YSZ–NiO specimens preconditioned by one-time reduction or by redox cycling at 600 or 800 °C, a certain mode of the material treatment was established which provides its improved physicomechanical properties. The oxidation behaviour of MAX-phases has been investigated at 600 °C in air. It was found that the intense initial oxidation of hot-pressed Ti3AlC2-based material can be eliminated by a certain mode of pre-oxidation. The oxidation resistance of the material can be significantly improved by niobium addition

Design of Anode Materials for IT SOFC:Effect of Complex Oxide Promoters and Pt Group Metals on Activity and Stability in Methane Steam Reforming of Ni/YSZ (ScSZ) Cermets

Ni/YSZ or Ni/ScCeSZ cermets were promoted by up to 10 wt % of fluoritelike (Pr-Ce-Zr- O, La-Ce-Zr-O, and Ce-Zr-O) or perovskitelike (La-Pr-Mn-Cr-O) oxides and small (up to 1.4 wt %) amounts of Pt group metals (Pd, Pt, or Ru). Reactivity of samples, their lattice oxygen mobility, and their ability to activate methane were characterized by temperature-programed reduction by CH4. The catalytic properties of these samples in methane steam reforming were studied at 500-850 degrees C and short contact times (10 ms) in feeds with 8 mol % of CH4 and steam/methane ratio of 1: 3. Oxide promoters ensure stable performance of cermets in stoichiometric feeds at T &gt; 650 degrees C by suppressing carbon deposition. Copromotion with precious metals enhances performance in the intermediate temperature (450-600 degrees C) range due to more efficient activation of methane. Factors determining specificity of these cermet materials' performance (chemical composition, microstructure, oxygen mobility in oxides, interaction between components, and reaction media effect) are considered. The most promising systems for practical application are Pt/Pr-Ce-Zr-O/Ni/YSZ and Ru/La-Pr-Mn-Cr-O/Ni/YSZ cermets demonstrating a high performance in the intermediate temperature range under broad variation in steam/CH4 ratio. [DOI: 10.1115/1.3117255]</p