Bilayer Cell Model and System Design of Highly Efficient Protonic Ceramic Fuel Cells

Abstract

A highly efficient power generation system was designed by minimizing leakage current in protonic ceramic fuel cells (PCFCs) using bilayer electrolytes. The best electrolyte designs are achieved by optimizing the cell efficiency based on the transport properties of electrolyte materials assuming hydrogen as fuel. In parallel, the effect of the electrodes on the overall cell performance was also considered. Additionally, a PCFC system was modeled using the designed cells. Two PCFC systems were investigated. One based on hydrogen as a fuel, and another based on methane as fuel. It was found that a bilayer electrolyte consisting of BaZr0.8Y0.2O3−δ (BZY) with a thin layer of lanthanum tungstate (La28-xW4+xO54+3x/2v2-3x/2) is the most effective at reducing leakage current at 600°C. For this cell, a system efficiency of 69% (LHV, DC) and 65% (LHV, AC) were obtained under the cell voltage of 0.93 V, with a leakage current ratio of less than 1%, and fuel utilization of 95% when using hydrogen as fuel. On the other hand, when methane was used as fuel, the efficiency increased up to 78% (LHV, DC) and 74% (LHV, AC).

Design and Fabrication of Protonic Ceramic Fuel Cells Based on BaZr0.8Y0.2O3−δ |BaZr0.1Ce0.7Y0.1Yb0.1O3−δ Bilayer Electrolyte

“…Hence, the calculations were started by assuming that the hydrogen partial pressures at the surface of the electrodes were the same as the bulk partial pressures and the iterations continued until the partial pressures did not change. 45 Although Eqs. 16-18 have already been derived and used in previous studies, 40,42 and the Butler-Volmer equation is widely used in the literature, [46][47][48][49][50][51] to the best of our knowledge, we are the first ones to use these equations combined in this way for the design of optimal bilayer electrolytes.…”