Methane-fueled thin film micro-solid oxide fuel cells with nanoporous palladium anodes

► Methane (CH4) was used to fuel thin film micro solid oxide fuel cells (μSOFCs). ► Pd was used as the μSOFC anode; while electrolytes and cathodes were 8mol.% YSZ and Pt, respectively. ► Nanoporous Pd synthesized at high sputtering pressures when thickness was less than 56nm. ► H2-fueled μSOFCs reached Pmax=145mWcm−2 and OCV=1.03V at 400°C. ► CH4-fueled μSOFCs reached Pmax=385mWcm−2 and OCV=0.77V at 550°C. Methane-fueled thin film micro-solid oxide fuel cells (μSOFCs) based on palladium (Pd) anodes are discussed in this article. The μSOFCs are composed of porous platinum (Pt) cathodes, 8mol.% yttria-stabilized zirconia (YSZ) ultrathin electrolytes, and Pd anodes – specifically, a Pt/YSZ/Pd heterostructure synthesized by physical vapor deposition. The Pt/YSZ/Pd μSOFCs exhibit a power density of 385mWcm−2 and an open circuit voltage of 0.77V at 550°C. A detailed study on synthesis, microstructure and functional properties of the nanoporous Pd films is presented. Possible anodic methane reactions, carbon deposition on Pd anodes, and carbon suppression approaches are discussed. The results are of potential relevance to advancing low temperature micro-fuel cell technology using hydrocarbon fuels.