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 ºC. The LSM (La0.8Sr0.2MnO3d)-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 cm2 at 0.7 V and 850 ºC for a standard cell having 50 vol% LSM and 720 and 805 mW cm2 at 0.7 V and 850 ºC 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.