Application of infiltrated LSCM-GDC oxide anode in direct carbon/coal fuel cells
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Hybrid direct carbon fuel cells (HDCFCs) utilise an anode based upon a molten carbonate salt with an oxide conducting solid electrolyte for direct carbon conversion. They can be fuelled by a wide range of carbon sources, and offer higher potential chemical to electrical energy conversion efficiency and potential to decrease CO2 emissions compared to coal-fired power plants. In this study, the application of (La, Sr)(Cr, Mn)O3 (LSCM) and (Gd, Ce)O2 (GDC) oxide anode was explored in HDCFC system based on a running with two different carbons, an organic xerogel and a raw bituminous coal. The electrochemical performance of the HDCFC based on 1-2 mm thick 8 mol.% yttria stabilised zirconia (YSZ) electrolyte and the GDC-LSCM anode fabricated by wet impregnation procedures was characterized and discussed. The infiltrated oxide anode showed a significantly higher performance than the conventional Ni-YSZ anode, without suffering from impurity formation under HDCFC operation conditions. Total polarisation resistance (Rp) reached 0.8-0.9 [capital Omega] cm2 from DCFC with oxide anode on xerogel and bituminous coal at 750oC, with open circuit voltage (OCV) values in the range of 1.1-1.2V on both carbon forms. These indicated the potential application of LSCM-GDC oxide anode in HDCFCs. The chemical compatibility of LSCM/GDC with carbon/carbonate investigation revealed that the emergence of A2BO4 type oxide in replacement of ABO3 perovskite structure in LSCM in reducing environment, due to Li attack as a result of intimate contact between LSCM and Li2CO3, with GDC being stable under identical conditions. Such reaction between LSCM and Li2CO3 was not observed on a LSCM-YSZ pellet treated with Li-K carbonate in 5%H2/Ar at 700oC, nor on GDC-LSCM anode after HDCFC operation. The HDCFC durability tests of GDC-LSCM oxide on xerogel and on raw bituminous coal were performed under potentiostatic operation at 0.7V at 750oC. The degradation mechanisms were addressed, especially on the raw coal.
Yue , X , Arenillas , A & Irvine , J T S 2016 , ' Application of infiltrated LSCM-GDC oxide anode in direct carbon/coal fuel cells ' Faraday Discussions , vol 190 , pp. 269-289 . DOI: 10.1039/C6FD00001K
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