Solid oxide cells for low-temperature operation and energy storage

Elizabeth Miller, Northwestern University

The need for large-scale energy storage is becoming more apparent as intermittent alternative energy sources such as solar and wind become more ubiquitous. Reversible solid oxide cells have shown promise for this application, but further investigation into materials systems and operating conditions is required to improve the relatively low roundtrip efficiency. While the thermodynamics of the reversible fuel cells are inherently endothermic, initial thermodynamic calculations have indicated that at low temperatures and increased pressure, the production of methane and hydrogen-rich gases from these reactions can be encouraged for chemical storage. In addition to alternative operating conditions, novel ceramic systems have been investigated for this application. (La0.9Sr0.1)0.98Ga0.8Mg0.2O3 (LSGM) is a promising electrolyte material with high ionic conductivity. LSGM can be used at lower temperatures and lower oxygen partial pressures than standard current electrolyte materials. Sr0.8La0.2TiO3 (SLT) is a ceramic with high electrical conductivity that has been investigated for use as an anode material. The materials are well suited to each other due to their compatible chemistries and coefficients of thermal expansion over a broad range of temperatures to which a solid oxide cell is subjected. Here the preliminary results of an anode-supported SLT/LSGM reversible fuel cell system are presented. This system is ideal for intermediate-temperature fuel cells and for reversible solid oxide cells for which further research will be conducted. In addition to a novel ceramic system, alternative pressure and temperature conditions will be examined.

Abstract Author(s): Elizabeth Miller, David Bierschenk, and Scott Barnett