Enhanced Mixed Electronic-Ionic Conductors through Cation Ordering
- Univ. of Houston, TX (United States)
- Univ. of Wisconsin, Madison, WI (United States)
- Stony Brook Univ., NY (United States)
The performance of many energy conversion and storage devices depend on the properties of mixed ionic-electronic conducting (miec) materials. Mixed or ambipolar conductors simultaneously transport ions and electrons and provide the critical interface between chemical and electrical energy in devices such as fuel cells, ion transport membranes, and batteries. Enhancements in storage capacity, reversibility, power density and device lifetime all require new materials and a better understanding of the fundamentals of ambipolar conductivity and surface reactivity.The high temperature properties of the ordered perovksites AA’B2O5+x, where A = rare earth ion, Y and B = Ba, Sr were studied. The work was motivated by the high oxygen transport and surface exchange rates observed for members of this class of mixed ionic and electronic conductors. A combined experimental and computational approach, including structural, electrochemical, and transport characterization and modeling was used. The approach attacks the problem simultaneously at global (e.g., neutron diffraction and impedance spectroscopy), local (e.g., pair distribution function, nuclear magnetic resonance) and molecular (ab initio thermokinetic modeling) length scales. The objectives of the work were to understand how the cation and associated anion order lead to exceptional ionic and electronic transport properties and surface reactivity in AA’B2O5+x perovskites. A variety of compounds were studied by X-ray and neutron diffraction, measurements of thermodynamics and transport and theoretically. These included PrBaCo2O5+x and NdBaCo2O5+x, PrBaCo2-xFexO6- δ (x = 0, 0.5, 1.0, 1.5 and 2) and LnBaCoFeO6- δ (Ln = La, Pr, Nd, Sm, Eu and Gd), Sr3YCo4O10.5, YBaMn2O5+x. A0.5A’0.5BO3 (where A=Y, Sc, La, Ce, Pr, Nd, Pm, Sm; A’= Sr, Ba; and B= Fe, Co, Mn, Ni), Ba2In2O5, and La1 xSrxCoO3-δ /(La1-ySry)2CoO4±δ interfaces.
- Research Organization:
- Univ. of Houston, TX (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- DOE Contract Number:
- SC0001284
- OSTI ID:
- 1233610
- Country of Publication:
- United States
- Language:
- English
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