Optimal design of protonic ceramic electrolyzers
Certain doped perovskite ceramics, such as yttrium-doped barium zirconates (BZY), barium cerates (BCY), and solid solutions thereof (BCZY), Yttrium and ytterbium co-doped barium zirconate-cerate (BaCe0.7Zr0.1Y0.1Yb0.1O3-δ, BCZYYb) have been widely used as protonic ceramic electrolyzers (PCEC) electrolyte materials. Compared to traditional solid oxide fuel cells (SOFC), PCEC can be operated at intermediate temperatures because the good protonic conductivity of these materials at relatively low temperatures (400C-700C). At this temperature regime, these proton conducting perovskites are in fact mixed ionic-electronic conductors (MIECs). Thus, besides charged-defect transport of protons, oxygen vacancies transport (which will introduce oxygen partial pressure distribution in the electrolyte that may influence the chemical stability of the electrolyte) and electrons (e), and/or electron holes (h) transport (which will introduce current leakage during operation of PCEC) need to be studied. According to experimental results, less Ceria in the electrolyte material can introduce higher Faraday efficiency and smaller proton conductivity. In order to achieve an optimized performance, the optimal design of structure of PCEC electrolyte is in need. This is a joint project with Dr. Dong Ding’s group in Idaho National Lab.