Direct-write microfabrication of single-chamber micro solid oxide fuel cells

Single-chamber micro solid oxide fuel cells (SC-µSOFCs) are promising systems for portable power generation. Here we report the direct-write microfabrication and electrochemical testing of SC-µSOFCs in the single-face configuration which consists of closely spaced interdigitated electrodes on an electrolyte substrate. In direct-write microfabrication, powdered electrode materials are first synthesized into inks which are subsequently extruded through a micronozzle onto an electrolyte plate mounted on a robot-controlled platform. The microfabricated structures are then sintered to remove the organic components of the inks and to obtain porous electrodes. Processing-structure relationships were obtained using systematic experimentation for the direct-write microfabrication of nickel oxide-yttria stabilized zirconia (NiO-YSZ) anodes and lanthanum strontium manganite (LSM) cathodes on an YSZ electrolyte. Single-chamber µSOFCs were fabricated with interdigitated electrodes of a few hundred microns in size. When tested in a fuel-air mixture (methane-to-oxygen ratio R_mix = 2) at a furnace temperature of 700 °C, the cells exhibited an open circuit voltage of 800 mV and a peak power density of ~1 mW cm^-2. Implications for the use of these devices for portable power generation are discussed.