高性能阴极是提高 SOFC 电池性能的关键因素。为了提高阴极电化学性能和降低阴极极化阻抗，本实验将Pechini 法制备的 LSM(La0.85Sr0.15MnO3)溶胶浸渍到 LSCF(La0.6Sr0.4Co0.2Fe0.8O3-δ)-GDC(10GDC)多孔阴极中，构成LSM-LSCF-GDC三相复合阴极。为了提高浸渍效率，研究了不同pH下LSM浸渍液的浸渍情况，研究发现： LSM浸渍液的 pH 是影响浸渍效果和浸渍量的直接因素。当 LSM 浸渍液为弱碱性时，络合物胶体粒子带负电，而LSCF-GDC的孔洞内壁带大量的负电，这样使得两者间的主要作用力为排斥力，有利于LSM胶体粒子进入阴极的孔洞内部。当LSM浸渍液pH为8.0时，生成的LSM纳米颗粒能较均匀地分布在阴极骨架内壁，随着浸渍次数的增加，阴极的极化阻抗先减后增，浸渍3次的复合阴极具有最低极化阻抗0.16??cm2(700℃空气中)。在700℃下，以H2+3% H2O为燃料、空气为氧化气体，浸渍与未浸渍的电池的最大功率密度分别为0.645 W/cm2和0.503 W/cm2。
The cathode with high performance is a key factor to improve the electrochemical properties of SOFC. In order to increase the electrochemical properties and reduce the polarization impedance of the cathode, LSCF (La0.6Sr0.4Co0.2Fe0.8O3-δ)-GDC(10GDC) porous cathode was dipped by the LSM(La0.85Sr0.15MnO3) sol which was preparedvia Pechini method, and then the LSM-LSCF-GDC three-phase composite cathode was constituted after calcinations. To improve the efficiency of impregnation, LSM sol with different pH was used to impregnate. The pH of LSM sol was the most important factor which affected impregnated effect and amount of impregnation. The complex colloid particles was negatively charged when LSM sol appeared weak alkaline. Meanwhile, a large num-ber of negative charges was existing on LSCF-GDC hole inner wall, indicaing the repelling force was the main force between the colloid particles and hole wall, helpful to the LSM colloid particles impregnate into the inside hole of the cathode. The results showed that the generated LSM nano particles could be evenly distributed on the inner wall of the cathode skeleton when the pH of LSM sol was equal to 8.0. Cathode polarization impedance in-creased firstly and then reduced with the increase of impregnation times. The composite cathode impregnated in LSM sol for 3 times attained the minimum polarization impedance of 0.16??cm2 (700℃in the air). The maximum power densities of impregnated and un-impregnated cells were 0.645 W/cm2 and 0.503 W/cm2, respectively, at the working temperature of 700℃, using 3% H2+H2O as fuel and air as oxidizing gas.
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