Enhanced triple-phase boundary density in infiltrated electrodes for solid oxide fuel cells demonstrated by high-resolution tomography

• Microstructure of nickel-infiltrated GDC scaffold is analyzed by FIB-SEM.
• TPB density and mean particle/pore sizes are quantified.
• Infiltrated electrodes have eight times larger TPB density than conventional electrodes.
• Shorter TPB segments are generated by infiltration than conventional methods.
• Infiltration technique has a potential to better control porous microstructure.

This paper, for the first time, demonstrates the three-dimensional imaging of nano-particle infiltrated Ni–GDC (gadolinia-doped ceria) electrodes using focused ion beam tomography. Microstructural parameters of the actual electrode microstructure are quantified, such as volume fraction, TPB density and mean particle/pore sizes. These microstructural parameters reveal that the infiltrated electrodes have eight times larger TPB density than conventional electrodes fabricated by powder mixing and sintering methods. Comparison between the infiltrated electrodes and conventional electrodes indicates that the infiltrated electrodes have a greater potential to independently control metal particle size, porosity and TPB density, which is a significant advantage in developing design optimized electrode microstructures.

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