纳米YSZ阵列的制备及固体氧化物电解池堆性能研究

发布时间：2018-03-26 03:48

  本文选题：固体氧化物电解池　切入点：纳米阵列　出处：《中国地质大学(北京)》2015年硕士论文

【摘要】：固体氧化物电解池是一种新型的能源利用方式,可以将电能转化为化学能,且具有高效、清洁的优点。现有的固体氧化物电解池多为无序化的多孔复合陶瓷结构,存在电极强电化学极化、强浓差极化、原料气转化率低以及短寿命的关键科学问题。此外,传统的SOEC以YSZ为电解质、Ni-YSZ为氢电极、LSM-YSZ为氧电极,由于LSM-YSZ氧电极的氧离子电导率过低,而具有混合电导的LSCF氧电极材料因具有更高的催化活性和更高的电导率而受到广泛关注。本论文主要分为两部分。第一部分为固体氧化物电解池中有序化纳米电解质材料的制备工作。本部分通过采用多种水热、电泳、溶胶凝胶和热压等制备方法,借以容易除去的AAO模板,制备有序化的YSZ纳米阵列。结果表明通过溶胶凝胶-模板法成功制备了高度有序化的YSZ纳米阵列,为后期纳米阵列电极的制备提供了良好基础。第二部分为以LSCF-GDC(La0.6Sr0.4Co0.2Fe0.8O3-δ-Ce0.9Gd0.1O1.95)为氧电极的固体氧化物电解池堆(30单元10×10 cm2的平板式电解池堆)的电解性能测试。在不同的操作温度、气体流量和水蒸气含量等实验条件下进行了电解水蒸气研究,并在前人的基础之上建立了电解水蒸气的电化学模型和系统效率模型主要得出了以下结论:高温有利于欧姆极化和电化学极化降低;高水蒸气含量能明显的降低电化学活化极化损失;氢气极气体的流量则对降低浓差损失作用明显;向氧气极通入空气能显著的降低电化学极化损失,但是纯氮气的通入却使电化学极化损失增加。通过计算不同实验条件下高温电解水蒸气实验的系统效率,结果发现:高温、高水蒸气含量、高气体流量及氧电极空气的通入虽然能降低极化损失,减少电解所需的电能,但是同时也增加了加热气体所需的能量;经对比发现,在800℃氧气极不通入气体,氢气极通入6 L·min-1湿度为90%氢气,电流密度为0.323 A·cm-2时,系统效率最大为80.8%。
[Abstract]:Solid oxide electrolysis cell is a new type of energy utilization method, which can convert electric energy into chemical energy, and has the advantages of high efficiency and cleanliness. There are some key scientific problems such as strong electrochemical polarization, strong concentration polarization, low conversion of raw gas and short life. In addition, the traditional SOEC uses YSZ as electrolyte Ni-YSZ as hydrogen electrode and LSM-YSZ as oxygen electrode, because the oxygen ion conductivity of LSM-YSZ oxygen electrode is too low. However, LSCF oxygen electrode materials with mixed conductance have attracted much attention because of their higher catalytic activity and higher conductivity. This thesis is mainly divided into two parts. The first part is the ordered nanoscale electricity in the solid oxide electrolytic cell. Preparation of pyrolytic materials. Electrophoretic, sol-gel and hot-pressing methods were used to prepare the ordered YSZ nanoarrays by removing the AAO templates easily. The results showed that the highly ordered YSZ nanoarrays were successfully prepared by the sol-gel template method. In the second part, the electrolysis performance of solid oxide electrolytic cell with oxygen electrode as oxygen electrode is measured by using LSCF-GDCA La0.6Sr0.4Co0.2Fe0.8O3- 未 -Ce0.9Gd0.1O1.95 as oxygen electrode. The electrolytic water vapor was studied under the experimental conditions such as gas flow rate and water vapor content. The electrochemical model and system efficiency model of electrolytic water vapor were established on the basis of previous studies. The main conclusions are as follows: high temperature is conducive to the reduction of ohmic polarization and electrochemical polarization; High water vapor content can obviously reduce the polarization loss of electrochemical activation, while the flow rate of hydrogen gas can obviously reduce the loss of concentration, and the loss of electrochemical polarization can be significantly reduced by air flowing into the oxygen pole. However, the input of pure nitrogen increases the electrochemical polarization loss. By calculating the system efficiency of high temperature electrolytic water vapor experiment under different experimental conditions, the results show that: high temperature, high water vapor content, Although the high gas flow rate and the air flow through the oxygen electrode can reduce the polarization loss and reduce the electric energy required for electrolysis, it also increases the energy required to heat the gas. By comparison, it is found that oxygen is extremely impassable at 800 鈩，

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