随着能源问题和环境问题的日趋严重，氢能、核能等清洁能源受到越来越多的关注。高温电解水蒸气制氢（HTSE）技术能够高效利用第四代先进核反应堆提供的电能和工艺热来电解水蒸气，获得高纯的H2和O2，此法是未来大规模制氢的理想方法之一，且转换效率能达到50%。固体氧化物电解池（SOEC）是固体氧化物燃料电池（SOFC）的逆过程装置，也是高温电解水蒸气制氢的核心装置。但由于工作环境、电极极化方向的不同，SOEC对于材料的合成、电解池的制备及运行等都提出了全新的要求，因此开发更高效、更优异的材料和电解池制备工艺是实现SOEC商业化的重要课题。本文的主要研究成果如下：1）钙钛矿结构的材料具有结构稳定、氧化还原性能稳定、催化活性高等优点，能够成为常见的氢电极材料Ni-YSZ的替换材料。采用固相法合成Sr2FeNbO6、La0.9Sr0.1Ga0.8Mg0.2O3-δ和La0.8Sr0.2O3三种（双）钙钛矿结构材料，并证明了这三种材料在高温下结构和物理化学性质的稳定。结果表明：固相法得到的这三种材料物相单一，均属于钙钛矿结构；在温度低于1400℃时，SFN与LSGM能够稳定存在，不会发生固相反应；SFN-LSGM复合氢电极材料具有较高的电导率，导电性能优异，且与电解池材料LSGM热膨胀系数相近，可以应用于SOEC氢电极。2）采用干压法制备SOEC氢电极支撑体，并采用丝网印刷的方式制备电解质层和氧电极层，得到了结构为SFN-LSGM/LSGM/LSM-LSGM的电解池。该电解池在1.3V的电解电压下，在850℃，结构为SFN-LSGM/LSGM/LSM-LSGM的电解池制氢效率约为110ml/cm2?h。3）通过调整氢电极中造孔剂的掺入量调节其孔隙率，研究了氢电极孔隙率对电解池电化学性能及产氢速率的影响，结果表明：随着氢电极支撑体中孔隙率的增加，电解池的欧姆阻抗与极化阻抗均有所下降，产氢速率则有所提高，说明在一定范围内，提高氢电极层的孔隙率能在一定程度上提高SOEC的产氢速率。
With the energy and environment issues becoming increasingly serious, some clean energy such as hydrogen energy, nuclear energy catches more and more attentions. High temperature steam electrolysis (HTSE) can electrolyse steam into pure hydregon and oxygen efficiently by combining electric energy with thermal energy which are provided by the 4th generation reactors. This method is considered to be one of the best hydregon production methods on a large scale, and the transfer efficiency can reach about 50%. Solid oxide electrolysis cell (SOEC) is the key device of HTSE, and it is the inverse process of Solid oxide fule cell (SOFC). However, because of the difference about its working environment and the direction of the electro polarization, SOEC arises many new demands on the synthesis and preparation of materials, the preparation and operations of the cells. Therefore, developing more efficient materials and preparation technologies become a significant research project for the commercialization of SOEC. The double-perovskite materials like Sr2FeNbO6 are stable in redox conditions at high temperature, and they also have high catalytic activities, which makes it possible for these materials to replace Ni-YSZ and be applied to the cathode electrode of SOEC. Sr2FeNbO6 (SFN)、La0.9Sr0.1Ga0.8Mg0.2O3-δ (LSGM) and La0.8Sr0.2O3 (LSM) were synthesized by the solid-phase synthesis, and the structural stability and some other properties of these materials were investigated. The results show: these materials are pure and stable; SFN and LSGM can exist stably at high temperature; the electrical properties of the composite electrode made by SFN and LSGM are excellent; their coefficient of thermal expansion agrees with LSGM, which makes it perfect for the cathode electrode of SOEC.The support of SOEC was made by dry pressing method, and the electrolyte layer and the positive electrode layer were made by silk-screen printing method. The hydrogen production rate of the SOEC (SFN-LSGM/LSGM/LSM-LSGM) was about 110mL/cm2/h under experimental conditions at 850℃.The mass fraction of starch in cathode electrode was changed to adjust the porosity, in order to study the influence of porosity on the electrochemical properties and hydrogen production rate of the SOEC. The results show: with the increase of the porosity, the resistance of the SOEC was decreased slightly, and the hydrogen production rate was increased, which proved that to some extent, the increment of the porosity in the cathode electrode can rise the hydrogen production rate.
