Solid oxide cells operated reversibly or in electrolysis mode are promising for energy storage, but oxygen electrode degradation is an issue. Prior stability studies have focused on the widely-used powder-processed perovskite oxide electrodes in devices operating at ≥ 700 °C. Here we provide initial results on a different type of electrode designed for lower temperature - the Ruddlesden-Popper material La2NiO4 with a nano-scale structure produced by infiltration into a La0.9Sr0.1Ga0.8Mg0.2O3 scaffold. Life tests were performed in air at 650 °C on symmetric cells with La0.9Sr0.1Ga0.8Mg0.2O3 electrolytes with the current direction reversed every 6 h over 1000 h. The voltage degradation rate increased from ∼3%/kh at a current density of 1.0 A/cm2 to ∼15%/kh at 2.0 A/cm2. EIS measurements revealed that both the ohmic and polarization resistances increased more rapidly at the higher current density. Post-test observations showed no electrode delamination, but increased current density caused a change in the La2NiO4 nano-structure, along with evidence of electrolyte fracture.
ASJC Scopus subject areas
- Renewable Energy, Sustainability and the Environment
- Energy Engineering and Power Technology
- Physical and Theoretical Chemistry
- Electrical and Electronic Engineering