Protonic Ceramic Fuel Cell
Because of the generally lower activation energy associated with proton conduction in oxides compared to oxygen ion conduction, protonic ceramic fuel cells (PCFCs) should be able to operate at lower temperatures than solid oxide fuel cells (250° to 550°C versus ≥600°C) on hydrogen and hydrocarbon fuels if fabrication challenges and suitable cathodes can be developed. We fabricated the complete sandwich structure of PCFCs directly from raw precursor oxides with only one moderate-temperature processing step through the use of sintering agents such as copper oxide. We also developed a proton-, oxygen-ion–, and electron-hole–conducting PCFC-compatible cathode material, BaCo0.4Fe0.4Zr0.1Y0.1O3-δ (BCFZY0.1), that greatly improved oxygen reduction reaction kinetics at intermediate to low temperatures. We demonstrated high performance from five different types of PCFC button cells without degradation after 1400 hours. Power densities as high as 455 milliwatts per square centimeter at 500°C on H2 and 142 milliwatts per square centimeter on CH4 were achieved, and operation was possible even at 350°C.
- Duan C., Tong J., Shang M., Nikodemski S., Sanders M., Ricote S., Almansoori A., O’Hayre R. Readily processed protonic ceramic fuel cells with high performance at low temperatures, Science 349 (2015) 1321-1326.
- Duan C., Hook D., Chen Y., Tong J., O’Hayre R. Zr and Y co-doped perovskite as a stable, high performance cathode for solid oxide fuel cells operating below 500° C, Energy & Environmental Science, (2017)
- Nikodemski S., Tong J., Duan C., O’Hayre R. Ionic transport modification in proton conducting BaCe 0.6 Zr 0.3 Y 0.1 O 3− δ with transition metal oxide dopants, Solid State Ionics 294 (2016) 37-42
Solar Thermochemical Hydrogen Production
The STCH is a two-step high temperature water splitting process where sun heat is used to reduce the oxide material to a ABO3-δ or BO2-δ, creating oxygen vacancies, followed by a lower temperature step, where steam is introduced. The material splits water, by filling back the oxygen vacancies, and produces hydrogen in a carbon-neutral way. The goal in this project we design new materials for STCH that have higher H2 production capacity than the state-of-the-art ceria, and comparable reaction kinetics. The materials are predicted by computational DFT calculations combined with materials chemistry intuition, and tested in the Stagnation Flow Reactor at Sandia National Laboratory.
- Deml AM., Holder AM., O’Hayre R., Musgrave CB, Stevanovic V. Intrinsic Material Properties Dictating Oxygen Vacancy Formation Energetics in Metal Oxides, The Journal of Physical Chemistry Letters, 6 (2015) 1948-1953
- McDaniel AH., Miller EC., Arifin D., Ambrosini A.,Coker EN.,O’Hayre R., Chueh WC., Tong J. Sr-and Mn-doped LaAlO3− δ for solar thermochemical H2 and CO production, Energy & Environmental Science, 6 (2013) 2424-2428
Triple Conducting Oxides for Electrochemical Energy Conversion and Storage
This research is focused on understanding the effects of transition metal doping on triple conduction behavior in perovskite oxides to manipulate this behavior for particular applications. Specifically, we are working to develop a cathode for intermediate-temperature proton conducting fuel cells.
The research is conducted mainly at NREL, where we work with Dr. Andriy Zakutayev. We use NREL’s combinatorial pulsed laser deposition facilities for synthesis and combinatorial characterization tools for high-throughput screening.
- Ubic, R., Tolman, K., Talley, K., Joshi, B., Schmidt, J., Faulkner, E., Owens, J., Papac, M., Garland, A., Rumrill, C., Chan, K., Lundy, N., Kungl, H. Lattice-constant prediction and effect of vacancies in aliovalently doped perovskites. Journal of Alloys and Compounds. 644 (2015) 982-995.
- Tolman, K., Ubic, R., Papac, M., Seymour, K, McCormack, S., Kriven, W., Kungl, H. Structural effect of aliovalent doping in lead perovskites. Journal of Solid State Chemistry. 225 (2015)359-367.
- Tolman, K., Ubic, R., Papac, M., Kungl, H. Vacancy Modeling in Lead Titanate and Lead Zirconate Titanate. Processing and Properties of Advanced Ceramics and Composites VI: Ceramic Transactions. 249 (2014) 215-222