A study of process parameters of LSM and LSM-YSZ composite cathode films prepared by screen-printing

A screen-printing technique was developed to fabricate porous cathode film for solid oxide fuel cells. Several key process parameters such as the selection of binders, the mesh of screen, sintering temperature and sintering time were investigated and reported. SEM results showed that the selected process parameters exerted obvious influences on the structure of the screen-printed cathode film. Impedance spectra data were used to evaluate the performance of cathode films made by different process parameters. The optimized process parameters were as follows: ethyl cellulose used as a binder, 120 mesh screen-printing sintering at 1200 degrees C for 2 It. Based on the optimized parameters, the polarization resistance of pure LSM cathode was 0.396 Omega cm(2) at 800 degrees C; the LSM-YSZ composite cathode displayed R(p) value of 0.2027 Omega cm(2) at 850 degrees C, 0.2463 Omega cm(2) at 800 degrees C and 0.5168 Omega cm(2) at 750 degrees C, respectively. The performance of the LSM-YSZ composite cathode improved significantly after being polarized at 300 mA cm(-2) and 800 degrees C for 150 h. After 150 h, the over-potential of the composite cathode was stable. (C) 2007 Elsevier B.V. All rights reserved.