Symmetric, free standing thin film micro-solid oxide fuel cells of Pt/Y0.16Zr0.84O1.92/Pt structure are studied in this report. The role of parameters such as electrolyte thickness and electrode porosity on fuel cell power output was investigated. A peak power density of 1037 mW cm(-2) was exhibited with an optimized structure consisting of nano-porous Pt electrodes and 100 nm thick Y0.16Zr0.84O1.92 with an open circuit voltage of 0.968 Vat 500 degrees C using H-2 as fuel and standing air as the oxidant. A twelve hour test of these devices indicates that overall performance shows extreme sensitivity to microstructural changes in the pure metallic electrodes. Results presented herein enable mechanistic routes to performance optimization, provide device stability data and are relevant to advancing micro-fuel cells for portable energy. (C) 2010 Elsevier B.V. All rights reserved.