A performance assessment study on solid oxide fuel cells for reduced operating temperatures

• A model of a planar solid oxide fuel cell (SOFC) is developed to assess cell performance at low operating temperatures.
• The effects of different operating and design conditions on cell performance are presented.
• The electrolyte ohmic polarizations of SOFC with YSZ as electrolyte material are evaluated for different electrolyte thicknesses.
• The voltage and overall cell efficiencies are evaluated over a range of operating temperatures.

In this paper, a conventional solid oxide fuel cell (SOFC) is modeled, and its performance is assessed to investigate the main challenges that limit low temperature operation. SOFCs have numerous advantages over other fuel cell technologies; however, a major drawback of SOFCs is the high operating temperature (over 600 °C) which significantly reduces SOFCs lifetime and constrains manufacturing materials to costly produced composites. Therefore, the development of a low temperature solid oxide fuel cell (LT-SOFC) will improve the cost effectiveness of this technology and thereby enhance efficient energy utilization and contribute to CO2 emission reduction. In this regard, a model is employed to predict the conventional SOFC performance under different operating and design conditions, in general, and at low operating temperatures, in particular. Furthermore, the contribution of each of the polarizations is evaluated. The model results are validated through a comparison with published experimental data and found to be in a good agreement with a maximum possible error value of 10.3% in cell potential and power density output. The results show that conventional SOFCs are vulnerable to a significant performance reduction when operating at low temperatures (below 600 °C). In addition, the polarization that SOFCs experience at low operating temperatures is mainly attributed to electrolyte ohmic loss.