Monolithic electrolyte-supported solid oxide fuel cells fabricated by gel-casting on 3D-printed moulds

Abstract

A new approach for fabricating monolithic electrolyte-supported Solid Oxide Fuel Cells based on gel-casting technique on 3D-printed moulds is proposed to enhance their electrochemical and mechanical performances. Conventional planar and honeycomb configurations of 8 mol% yttria-stabilized-zirconia (YSZ) electrolytes were gel-casted. Proper aqueous ink formulations of YSZ and agarose gelling agent were prepared, and moulds made of polylactic acid filament were fabricated by 3D-printing. The mechanical behaviour of gel-casted ceramics was compared with cold-isostatic-pressed ones, using ball-on-3-balls bending strength and nanoindentation tests. Complementarily, the effect of electrolyte geometry on the mechanical stress distribution was investigated by finite element simulation. Finally, complete fuel cells were fabricated and electrochemically characterized, using Ni-YSZ anode and lanthanum-strontium-manganite-YSZ cathode. Electrochemical performance of the honeycomb cell (227 mW·cm⁻² at 900°C) was significantly higher than the planar one (189 mW·cm⁻² at 900°C). The electrochemical and mechanical properties of gel-casted electrolytes, close to state-of-the-art ones, validate this new approach.