Nanoscale membrane electrolyte array for solid oxide fuel cells

This paper presents a fabrication method for a low temperature micro-solid oxide fuel cell (mu-SOFC), featuring a large number of free-standing nano thin film electrolyte membranes. The mu-SOFC was fabricated by simple silicon-based MEMS processes to create a membrane array structure that renders high surface area density and mechanically stable support for yttria-stablized zirconia (YSZ) with only 70 nm in thickness. A total number of 765 to 6885 circular YSZ electrolyte membranes with a diameter of 50 mu m were enclosed within 2 mm to 6 mm square arrays. The active membrane area density on a silicon wafer surface was increased up to 20 times higher than that of previously reported structures. A 2 mm mu-SOFC array was tested at 350, 400, and 450 degrees C, and maximum power outputs of 1.78 mW, 2.43 mW, and 2.98 mW were obtained, respectively. Total power output of the high performance micro-SOFCs was increased from microwatts up to the milliwatt scale, and can be easily scaled up further for higher power output by this method. (C) 2011 Elsevier B.V. All rights reserved.