摘要固体氧化物燃料电池（SOFC）是一种在中高温下直接将储存在燃料和氧化剂中的化学能高效、环保地转化为电能的全固态化学发电装置。本文主要研究对象为LSCF-SDC纳米结构复合阴极，对以下几个内容进行研究：钐稳定氧化铈（SDC）粉体的制备、SDC浆料的制备、丝网印刷制备骨架、离子浸渍法制备电极并且对LSCF-SDC纳米结构复合阴极的低温制备与电化学性能进行研究。通过X射线衍射仪（XRD）、扫描电镜（SEM）与电化学阻抗谱等，推断样品相组成、观察其微观结构，分析烧结性能，表征其极化电阻及电化学性能，从而得出纳米粒子浸渍量与煅烧温度对阴极性能产生的影响。研究结果显示：离子浸渍法可以获得LSCF-SDC纳米离子的多孔结构，LSCF纳米颗粒均匀分布于SDC的多孔骨架中，二者间没有生成中间反应物。通过离子浸渍工艺制备的LSCF-SDC复合阴极在800℃下煅烧，形成LSCF纳米粒子均匀附着的复合阴极。LSCF-SDC纳米结构复合阴极在工作温度为700℃时阻抗值为0.327Ωcm2，约为未浸渍电池阻抗值（0.458Ωcm2）的71%，工作温度为750℃时阻抗值为0.172Ωcm2，约为未浸渍电池阻抗值（0.274Ωcm2）的63%，工作温度为800℃时阻抗值为0.124Ωcm2，约为未浸渍电池阻抗值（0.195Ωcm2）的64%。复合阴极的极化电阻相比于单纯的LSCF电极的极化电阻较低，因此适合做中温固体氧化物电池材料。浸渍法制备工艺能够明显降低电解质与阴极之间的热膨胀系数的差距，有效地解决了阴极与电解质热膨胀系数差距大所引起的热应力问题，避免高温工作下，电池因热膨胀失配而失效的问题。68046

毕业论文关键词  固体氧化物燃料电池  复合阴极  离子浸渍法

Title  Regulation of the microstructure of LSCF-SDC nanoelectrode

Abstract

Solid oxide cells (SOFC) is an energy conversion device converting chemical energy which is stored in the fuel and oxidizer to electrical energy efficiently and environmentally friendly in a high temperature. In this paper, nano-structured LSCF - SDC composite cathode is studied, Researches include the following sections: the preparation of SDC powder, preparation of SDC slurry, preparing frame by screen printing, the preparation of electrodes by Ion impregnation and the low temperature preparation with electrochemical properties of nano-structured LSCF - SDC composite cathode. Its phase composition, microstructure, sintering properties, the polarization resistance and electrochemical properties are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical impedance spectroscopy. The results show that: ion impregnation method can get LSCF-SDC porous structure of nano-ions. The nano-particles LSCF distributed in the porous skeleton of the SDC, there has no reactants produced between them. LSCF-SDC composite cathodes  prepared by ion- impregnation process and calcined at 800 ℃ form LSCF composite cathodes which nano-particles adhered uniformly.The polarization resistance of nano-structured LSCF-SDC composite cathode at 700 ℃and 750 ℃ are0.327Ωcm2 and 0.172Ωcm2. The polarization resistance of composite cathode is lower than pure LSCF electrode. There for, it’s suitable for intermediate temperature solid oxide battery materials. Composite cathodes prepared by impregnation can significantly reduce TEC gap between the electrolyte and the cathode, effectively solving the problem that TEC of cathode and the electrolyte does not match each other,which is caused by thermal stress, avoiding failure of the batteries due to thermal expansion mismatch in high temperatures.

Keywords solid oxide fuel cell(SOFC)  composite cathode  Ion impregnation method

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