Microtubular solid oxide fuel cells with lanthanum strontium manganite infiltrated cathodes

Abstract

Microtubular solid oxide fuel cells (mT-SOFCs) with infiltrated cathodes were fabricated and their electrochemical performance were compared with standard cells. For this purpose, NiO-YSZ (yttria stabilized zirconia) microtubular supports were fabricated by cold isostatic pressing (CIP) of NiO, YSZ and pore former powders, followed by spray coating of the YSZ electrolyte and co-sintering at 1400 °C. The LSM (La0.8Sr0.2MnO3−δ)-YSZ oxygen electrode is deposited by infiltration of LSM (into a thin porous YSZ layer). One of the advantages of this fabrication method is an increase of TPB (triple-phase boundary) length compared with the standard LSM-YSZ composite due to the much finer dispersed LSM particles having a higher active surface area towards oxygen reduction.The effect of the infiltrated amount in cell performance was studied. Two cells with identical anode support and thin layer electrolyte and 22 vol% (cell A) and 35 vol% (cell B) infiltrated LSM were prepared. The infiltrated cells showed an increase of up to 50% in terms of power density compared to the standard cell (550 mW cm−2 at 0.7 V and 850 °C for a standard cell having 50 vol% LSM and 720 and 805 mW cm−2 at 0.7 V and 850 °C for infiltrated cells A and B, respectively). The results indicate that the infiltrated cathode with fine distributed LSM particles improve the fuel cell performance using a lower LSM content compared with standard LSM-YSZ composite cathodes.