Optimization of large area solid oxide fuel/electrolyzer cells with aqueous tape casting

• Main Author: Goh, Gerald Jian Hao
• Other Authors: Chan Siew Hwa
• Format: Final Year Project
• Language: English
• Published: 2015
• Subjects: DRNTU::Engineering::Materials::Ceramic materials; DRNTU::Engineering::Mechanical engineering::Alternative, renewable energy sources
• Online Access: http://hdl.handle.net/10356/64570
• Institution: Nanyang Technological University

Solid Oxide Fuel Cell/Solid Oxide Electrolyzer Cell (SOFC/SOEC) is an emerging new source of energy today. It is part of the fuel cell technology family, which converts chemical energy to electricity. There is a lot attention paid to this plausible energy conversion system due to its environmentally friendly by-products. Much research is being conducted to optimise its performance and this is exactly what this Final Year Project is about. The study focuses on a planar design of the SOFC/SOEC and the substrate is fabricated by the means of aqueous tape-casting. There are 4 layers in the structure of this cell: support anode, NiO-YSZ (Nickel oxide and yttria stabilized zirconia); Active anode; NiO-YSZ; Electrolyte, YSZ and cathode, LSCF-GDC (Lanthanum strontium cobalt ferrite-gadolinium-doped ceria). There were 3 types of samples fabricated, anode active layer with tape-casted thickness of 300μm (Sample A) and anode active layer with tape-casted thickness of 200μm (Sample B) and the control without anode active layer (Sample C). It is theorized that an anode active layer may reduce the impedance and improve the performance. With a supply of 50ml/min of humidified H2 and air as the oxidant, these samples were tested for their performance and impedance. The temperature range was from 800°C down to 700°C. The impedance evaluation range was from 100kHz down to 10mHz. After completing the performance testing, the samples were investigated under the Scanning Electron Microscope (SEM) for their microstructure. Out of the 3 samples, Sample A was the best performer. A maximum power density of 283.49mW/cm2 has been achieved with an open circuit voltage of 1.080V at 800°C. Also at this temperature, an ohmic impedance of 0.45 Ωcm2 was recorded.