Effect of starting particulate materials on microstructure and cathodic performance of nanoporous LSM–YSZ composite cathodes

Nano-scale LSM–YSZ composite electrodes are prepared from a mixture of yttria stabilized zirconia (YSZ) and strontium-doped lanthanum manganite (LSM) particles. Commercial YSZ particles are mixed with polymerizable complex method-driven LSM powders of two different particle sizes, namely, 81 and 210 nm. Then, the correlations between the properties of the starting particles, sintering temperature, microstructure and cell performance are studied. Use of smaller LSM particles in the composite electrode induces extensive grain growth. This significantly reduces the triple phase boundary (TPB) and leads to an increase in the polarization resistance. The composite cathode derived from larger LSM particles exhibits a lower total polarization resistance (~0.31 Ω cm2 at 800 °C) and, subsequently, better maximum cell power (~630 mA cm−2). By contrast, larger resistance and lower cell power are observed for electrodes composed of smaller LSM particles.