This title appears in the Scientific Report : 2014 

Tokariev, O. (Corresponding Author)
Berger, Cornelius / Orzessek, P. / Fang, Q. / Menzler, N. H. / Buchkremer, H. P.
Elektrochemische Verfahrenstechnik; IEK-3
Werkstoffsynthese und Herstellungsverfahren; IEK-1
6th Forum on New Materials, Montecatini Terme (Italy), 2014-06-15 - 2014-06-19
Conference Presentation
Helmholtz Interdisciplinary Doctoral Training in Energy and Climate Research (HITEC)
Solid Oxide Fuel Cell
Fuel Cells
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This work focuses on the fundamental research of porous storage materials for a novel high temperature rechargeable oxide battery (ROB). In the battery, a solid oxide cell (SOC) runs alternately in fuel cell (discharge cycle) and electrolyzer (charge cycle) modes. The hydrogen produced in the electrolyzer mode makes the utilization of the battery safer, by avoiding external hydrogen storage systems. The stagnant atmosphere in the battery, consisting of H2 and H2O vapor, is used as a reducing and oxidizing agent for a metal-metal oxide material, which serves as the integrated energy storage unit. The storage components have to meet requirements such as; good kinetics of redox reactions, high oxygen storage capacity, and high lifetime, in order to assure a continuous ROB operation for at least 10,000 hours.Storage components are manufactured by type casting or extrusion using iron oxide based slurries or pastes. Because of long-term redox cycling at 800 °C, the structure of the Fe/FeO storage material degrades, making the material incapable of storing oxygen for continuous redox reactions. Hence, to prevent storage degradation, the Fe/FeO matrix was supplemented by “inert” (ZrO2, 8YSZ, Al2O3, MgAl2O4) as well as reactive oxides (Mn2O3, CeO2, Cr2O3, TiO2, CuO, Y2O3, SrO, SiO2, CaO, MgO) which are capable of promoting and/or inhibiting ageing and the kinetics of redox reactions.Thermogravimetric, XRD, and microstructural analysis after redox cycling in the redox furnace (420 h) show that the “inert” oxides hinder to some extent structural degradation, whereas reactive mixed oxides are fully capable of preventing sintering for several redox cycles. The influence of the powder parameters on the thermochemical processes in the ROB were also revealed as significant characteristics.