Synthesis of Solid Oxide Fuel Cell with Graded Structure from Aqueous Solution

为了实现固体氧化物燃料的实际应用，实现大面积、低电阻的轻量化、紧凑的电池堆是必要的，薄膜形状的陶瓷材料的使用是重要的。与CVD法、溅射法、溶胶-凝胶法等传统的薄膜形成方法相比，水溶液合成陶瓷薄膜可以形成面积大、形状复杂的均匀薄膜。该技术不需要热处理，但热处理对薄膜的变形和开裂是有害的。这是一个低成本的过程，因为不需要昂贵的设备。利用该技术的这些特点，可以通过逐渐改变溶液的组成来制备具有梯度结构的燃料电池。采用梯度结构制造燃料电池，可以使热膨胀系数连续变化，避免电池因热应力而断裂。在金属-氟配合物溶液中加入硼酸，使其与氟离子形成稳定的络合物，进行氟配合物的水解。通过该反应，可以在水溶液中合成氧化锆和镧过渡金属钙钛矿型氧化物。通过在真空球箱中合成，消除了空气中氧气的影响，对材料进行了精细控制。利用LB薄膜装置对衬底表面进行了精细控制。机理分析结果表明，种子晶体在水溶液合成中起着重要的作用。在常温常压条件下，可以在YSZ衬底上均匀高密度地沉积LaMnO_3颗粒。推测YSZ的部分溶解和LaMnO_3的沉积是同时进行的。这一结果提示了制造梯度结构的可能性。梯度结构燃料电池是解决电池热应力断裂问题的有效方法。由于LaMnO_3颗粒表面有许多不规则性，电极也被期望具有很高的活性。少

For the practical use of solid oxide fuel, the realization of lightweight and compact cell stack with large area and low electric resistance is necessary and the use of ceramic materials in thin film shape is important. Comparing with conventional methods for forming thin film, such as CVD, spattering and sol-gel method, synthesis of ceramic thin film from aqueous solution can form uniform thin film with large area and complicated shapes. This technique needs no heat treatment, which is injurious because of the possibility of deformation and crack of the thin film. It is low-cost process, because no expensive equipment is required. Using these characteristics of this technique, fuel cell with a graded structure can be made by gradually changing the composition of the solution. By making a fuel cell with graded structure, a coefficient of thermal expansion changes continuously and the fracture of the cell by thermal stress can be avoided. By adding boric acid, which can make stable comp … More lex with fluoride ion to metal-fluoro-complex solution, hydrolysis of the fluoro-complex proceeded. By using this reaction, zirconia and lanthanum-transition metal perovskite type oxide could be synthesized from aqueous solution. By synthesizing in a vacuum globe box, the influence of oxygen in air was eliminated and fine control of the material was conducted. By using LB films apparatus, the surface of substrates was finely controlled. The result of analyzing the mechanism made it clear that seed crystals play an important role in the synthesis from aqueous solution. By using this technique, LaMnO_3 particles could be deposited uniformly and in high density on an YSZ substrate at normal temperature and under normal pressure. It is supposed that partial dissolution of YSZ and deposition of LaMnO_3 proceeded simultaneously. This result suggests the possibility of manufacturing graded structure. A fuel cell with graded structure is promising solution for the fracture problem of the cell by thermal stress. The electrode is also expected remarkably high activity, because the surface of the LaMnO_3 particles has many irregularities. Less