Development of Solid Oxide Fuel Cell by Using Synthesis from Aqueous Solutions

Fuel Cells can convert chemical energy into electrical energy efficiently，avoiding the Carnot restriction。The solid oxide fuel cell(SOFC)is an all-solid-state power system which operates at high temperatures。SOFCs have mulitlayer structures where anode layer，electrolyte layer and cathode layer，all made of ceramics，are piled in sequence like sandwiches.Fabrication of highly efficient SOFC systems requires components in the form of thin films.Methods for synthesizing solid oxide fuel cell ceramic materials from aqueous solutions at ordinary temperatures and ordinary pressures are advantageous because of the applicability to making films with wide areas and/or complicated shapes with no requirement of vacuum or high temperature，and because of lower cost.Solutions of fluoro-complex ions were obtained by dissolving sodium hexafluorozirconate in distilled water or dissolving LaMeO Iai D23 I D 2(Me=Cr，Mn，Fe，Co)or(La，Sr)MeO I D 23 I D 2 perovskite prepared by usual solid state reaction in hydrofluoric acid.Boric acid was added into the solution，the fluoride ions were consumed by the formation of BF I D14-I D1 complex ion，and then the fluoro-complex ions were hydrolyzed to ZrO I D 22 I D 2，LaMeO I D 23 I D 2 or(La，Sr)MeO I D 23 I D 2 in order to increase the amount of fluoride ions.The high crystallinity of the product was confirmed by sharp and strong X-ray diffraction peaks.Aggregates of synthesized ZrO I D22 I D 2，LaMeO I D 23 I D 2 or(La，Sr)MeO I D 23 ii D 2 were observed on the substrates in scanning electron microscope images.Deposition of LaMnO I D23 II D2 on yttria stabilized zirconia substrate was performed by using this method。

Fuel Cells can convert chemical energy into electrical energy efficiently, avoiding the Carnot restriction. The solid oxide fuel cell(SOFC)is an all-solid-state power system which operates at high temperatures. SOFCs have mulitlayer structures where anode layer, electrolyte layer and cathode layer, all made of ceramics, are piled in sequence like sandwiches. Fabrication of highly efficient SOFC systems requires components in the form of thin films. Methods for synthesizing solid oxide fuel cell ceramic materials from aqueous solutions at ordinary temperatures and ordinary pressures are advantageous because of the applicability to making films with wide areas and/or complicated shapes with no requirement of vacuum or high temperature, and because of lower cost. Solutions of fluoro-complex ions were obtained by dissolving sodium hexafluorozirconate in distilled water or dissolving LaMeOィイD23ィエD2 (Me=Cr, Mn, Fe, Co)or (La,Sr)MeOィイD23ィエD2 perovskite prepared by usual solid state reaction in hydrofluoric acid. Boric acid was added into the solution, the fluoride ions were consumed by the formation of BFィイD14-ィエD1 complex ion, and then the fluoro-complex ions were hydrolyzed to ZrOィイD22ィエD2, LaMeOィイD23ィエD2or(La,Sr)MeOィイD23ィエD2 in order to increase the amount of fluoride ions. The high crystallinity of the product was confirmed by sharp and strong X-ray diffraction peaks. Aggregates of synthesized ZrOィイD22ィエD2, LaMeOィイD23ィエD2or(La,Sr)MeOィイD23ィエD2 were observed on the substrates in scanning electron microscope images. Deposition of LaMnOィイD23ィエD2 on yttria stabilized zirconia substrate was performed by using this method.