This study discusses the fabrication and electrochemical performance of micro-tubular solid oxide fuel cells (SOFCs) with an electrolyte consisting a single-grain-thick yttria stabilized zirconia (YSZ) layer. It is found that a uniform coating of an electrolyte slurry and controlled shrinkage of the supported tube leads to a dense, crack-free, single-grain-thick (less than 1 mu m) electrolyte on a porous anode tube. The SOFC has a power density of 0.39 W cm(-2) at an operating temperature as low as 600 degrees C, with YSZ and nickel/YSZ for the electrolyte and anode, respectively. An examination is made of the effect of hydrogen fuel flow rate and shown that a higher flow rate leads to better cell performance. Hence a YSZ cell can be used for low-temperature SOFC systems below 600 degrees C, simply by optimizing the cell structure and operating conditions. (C) 2010 Elsevier B.V. All rights reserved.