Journal of Power Sources, Vol.196, No.8, 3761-3765, 2011
Solid oxide fuel cell with compositionally graded cathode functional layer deposited by pressure assisted dual-suspension spraying
In this work, the benefit of compositionally grading a cathode functional layer (CFL) for solid oxide fuel cells (SOFCs) is explored. Cells are prepared wherein either a standard cathode functional layer (SCFL) or a linearly compositionally graded cathode functional layer (CGCFL) is placed between the cell electrolyte and cathode current collecting regions. The electrochemical performance of these cells is compared with a SOFC cell containing no CFL All cells are fabricated using a pressurized dual-suspension spraying system. Electrolytes, cathode functional layer, and cathode current collecting materials are deposited on a powder compacted anode support. SEM and EDAX area maps are taken to study the resulting micro-structures and to verify that the desired CFL profiles are produced. The EDAX area map verifies that a compositionally graded CFL and a SCFL are obtained. The cells are analyzed using impedance spectroscopy to evaluate the electrochemical performances of each cell. The open circuit voltage (OCV) and peak power densities of all three cells are 1.04V with 80 mW cm(-2), 1.12V with 108 mW cm(-2), and 1.08V with 193 mW cm(-2) at 850 degrees C for the SCFL cell, the cell without a CFL, and the compositionally graded CFL cell respectively. The results show that this approach is a viable means for producing SOFC functional layers with unique composition and interfacial properties. (c) 2010 Elsevier B.V. All rights reserved.
Keywords:Functional layer;Compositionally graded cathode;Solid oxide fuel cells (SOFC);Anode supported;Spray processing