Development of novel anode material for intermediate temperature SOFC (IT-SOFC)

Abstract

Solid oxide fuel cells (SOFC) offer a clean technology to electrochemically generate electricity and heat from hydrogen or hydrocarbon based fuel at high efficiencies. All the active components of the SOFC unit cell comprise of rare-earth or low abundant elements. An increase in the cost of rare-earths is likely to jeopardize the commercialization prospects of SOFC based technologies. Hence, a greater scientific effort should be focused on the development of rare-earth free SOFC materials. The previous research works on electrode-supported intermediate temperature solid oxide fuel cells (IT-SOFCs) indicate that the anode supported concept provides better electro-chemical performance than the cathode supported one. Therefore, the total material cost of anode-supported SOFC is largely governed by the cost of the anode material. The objective of the present investigation was, therefore, the development of a rare-earth free anode material for IT-SOFC. The present work envisages application of titanium oxycarbide as a possible rare-earth free anode material for intermediate temperature solid oxide fuel cells. Titanium oxycarbide samples (TiO_xC_1−x with x = 0.2–0.8) were prepared by reaction-sintering of TiO and TiC powders under vacuum at 1500 °C for 5 h. Basic studies on TiO_xC_1−x (x = 0.2–0.8) with respect to phase purity and stability under oxidizing and reducing environments were carried out. The compatibility of titanium oxycarbide with intermediate-temperature electrolyte material (Ce_0.9Gd_0.1O_3−δ) was studied. The electrochemical properties of planar cells using Ce_0.9Gd_0.1O_3−δ as electrolyte and employing TiO_0.2C_0.8 and La_0.8Sr_0.2Co_0.2Fe_0.8O_3−δ based anode and cathode materials were investigated. The present study indicates that titanium oxycarbide is an alternative anode material for IT-SOFC. This is the first report on the possibility of application of a rare-earth free ceramic in the form of titanium oxycarbide as a potential fuel electrode in IT-SOFC.