Characteristics of Oxygen Electrode Supported Reversible Solid Oxide Cells

Abstract

Oxygen-electrode-supported solid oxide cells (OESCs) have potential advantages over fuel-electrode-supported cells, including reduced fuel-electrode concentration polarization, better oxygen electrode current collection, and flexibility in the fuel electrode choice. However, there are serious drawbacks including the difficulty of co-firing the oxygen electrode and electrolyte, and oxygen electrode concentration polarization. This paper explores the characteristics of OESCs with La0.8Sr0.2MnO3−δ -Zr0.92Y0.16O2−δ (LSM-YSZ) electrode-support enhanced by SrTi0.3Fe0.6Co0.1O3−δ (STFC) infiltration, thin YSZ electrolyte, and SrTi0.3Fe0.7O3−δ (STF) fuel electrodes. The STFC infiltration increases fuel cell maximum power density by >1.5 times and electrolysis current density (at 1.3 V) by >2 times. Cell performance in pure oxygen is compared to that in air, exploring a possible reversible solid oxide cell system configuration where oxygen produced during electrolysis is stored and subsequently used during fuel cell operation. The fuel cell maximum power density is increased from 0.88 W cm−2 in air to 1.37 W cm−2 in oxygen, with limiting current increased from 1.7 to >5.6 A cm−2; the electrolysis performance is essentially unchanged, probably because the electrode air becomes enriched with oxygen during electrolysis.