Electrophoretic Codeposition of La_(0.6)Sr_(0.4)Co_(0.8)Fe_(0.2)O_(3-δ) and Carbon Nanotubes for Developing Composite Cathodes for Intermediate Temperature Solid Oxide Fuel Cells

摘要

Carbon nanotubes (CNTs)/La_(0.6)Sr_(0.4)Co_(0.8)Fe_(0.2)O_(3-δ) (LSCF) composite films have been fabricated by electrophoretic codeposition on Ce_(0.9)Gd_(0.1)O_(1.95) (CGO) substrates. CNTs are used as a sacrificial phase to produce ordered porous LSCF cathodes for intermediate temperature solid oxide fuel cells. The synthesis of LSCF powder by a modified sol-gel route is presented. The possible mechanism of formation of CNT/LSCF composite nanoparticles in suspension is discussed. Moreover the optimal suspension composition and the conditions for achieving successful electrophoretic deposition (EPD) of CNTs/ LSCF composite nanoparticles were evaluated. Experimental results showed that the CNTs were homogeneously distributed and mixed with LSCF nanoparticles forming a mesh-like structure, which resulted in a highly porous LSCF film when the CNTs were burned out during heat treatment in air at 800℃ for 2 h. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD) techniques were employed to characterize the microstructure of the precursors and of the composite films.