A comprehensive micro-scale model for transport and reaction in intermediate temperature solid oxide fuel cells

• Published in: Electrochimica acta Vol. 51; no. 17; pp. 3446 - 3460
• Main Authors: Nam, Jin Hyun, Jeon, Dong Hyup
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 25.04.2006; Elsevier
• Subjects: Applied sciences; Energy; Energy. Thermal use of fuels; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Exact sciences and technology; Fuel cell; Fuel cells; Micro-scale model; PEN (positive electrode/electrolyte/negative electrode); SOFC (solid oxide fuel cell); TPB (three phase boundary); Micro-scale model; TPB (three phase boundary); PEN (positive electrode/electrolyte/negative electrode); Fuel cell; SOFC (solid oxide fuel cell); Performance evaluation; Voltage current curve; Porous electrode; Theoretical study; Percolation theory; Solid oxide fuel cell; Transport process; Energetic efficiency; Numerical simulation; Electrochemical reaction; Electrical characteristic
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2005.09.041

A comprehensive model for detailed description of micro-scale transport and electro-chemical reaction in intermediate temperature SOFCs (solid oxide fuel cells) was developed by combining many relevant theoretical and experimental researches. Dependence of electro-chemical performance of PEN (positive electrode/electrolyte/negative electrode) on micro-structural parameters of electrodes was investigated through numerical simulation. Spatial distribution of transfer current density confirmed that TPBs (three phase boundaries) at electrode/electrolyte interface were most active for electro-chemical reaction and its contribution to overall reaction increased at higher current densities. Spatial gradient of total pressure in cathode was found to facilitate oxygen transport while that in anode hinder hydrogen transport. Among various micro-structural parameters for electrodes, particle diameter was found to be the most important one that governs the PEN performance; smaller particle diameter decreased activation overpotential with larger TPB length, while increasing mass transport resistance and concentration overpotential with smaller pore diameter. The proposed micro-model was found successful in micro-structural characterization of PEN performance, and thus believed to serve as a bridge connecting micro-scale models and macro-scale calculations.