A rapid analytical assessment tool for three dimensional electrode microstructural networks with geometric sensitivity

• Published in: Journal of power sources 2014, Vol.246, p.322-334
• Main Authors: NELSON, George J, NAKAJO, Arata, CASSENTI, Brice N, DEGOSTIN, Matthew B, BAGSHAW, Kyle R, PERACCHIO, Aldo A, GUOLIANG XIAO, STEVE WANG, FANGLIN CHEN, CHIU, Wilson K. S
• Format: Article
• Language: English
• Subjects: Applied sciences; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Electrodes; Energy; Energy. Thermal use of fuels; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Exact sciences and technology; Finite element method; Fuel cells; Mathematical analysis; Mathematical models; Microstructure; Nanostructure; Networks; Three dimensional
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2013.07.009

Electrochemical fin theory is applied to the microstructural analysis of Sr sub(2)Fe sub(1.5)Mo sub(0.5)O sub(6- delta ) (SFM), a redox stable solid oxide fuel cell (SOFC) electrode. The electrode microstructure is imaged by X-ray nanotomography, then partitioned into a network of resistive components with distinct geometric characteristics. The network is analyzed using an analytical electrochemical fin network model. The resulting predictions of electrode performance are compared to predictions made using three-dimensional finite element simulations of charge transport with surface electrochemical reactions in the imaged micro-structure. For a representative subvolume of the structure, the electrochemical fin and finite element models provide comparable predictions. Analysis of larger representative volume elements extracted from the X-ray nanotomography data demonstrates good agreement with experimental measurements of the electrodes analyzed. Finally, advantages of applying the analytical electrochemical fin network models to real microstructures are addressed, particularly with respect to significant reduction in memory requirements and computational time. The use of the electrochemical fin theory is able to rapidly analyze real microstructures with microstructural details that are comparable to finite element and lattice Boltzmann methods, but at volume sizes that finite element and lattice Boltzmann methods were not able to perform due to limits in memory and computational time.