WEB Electrode materials for reversible solid oxide cells (SOC) – an overviewWednesday (01.01.2020) 00:00 - 00:30 Part of:
Solid oxide cells (SOC) are an attractive electrochemical energy conversion technology that can convert chemical fuels into electrical energy (fuel cell mode, SOFC) and split chemicals like water or CO2 into their constituents using electrical energy (electrolysis mode, SOEC). Reversible operation in SOFC/SOEC mode is possible in one system (rSOC). In both modes, however, a significant loss of efficiency is a result of the polarization processes at the fuel and air electrodes.
The air electrodes are typically mixed ion and electron conducting (MIEC) perovskite oxides. The most widely used material is La1-xSrxCo1-yFeyO3- (LSCF) due to its favorable combination of electrochemical activity and stability. The main mechanisms of electrode polarization and degradation will be discussed using LSCF as an example, highlighting the importance of both material properties and microstructure. An overview of alternative air electrodes will be presented.
The fuel electrodes are typically dual-phase components consisting of a metal such as Ni and an ion conducting phase. The most widely used ion conductors are yttria-stabilized zirconia and doped ceria. The main loss mechanisms in the fuel electrode will be discussed with regard to the physical properties of the cermets and their microstructure. The impact of materials compatibility and the impact of processing on the cell performance will be discussed for both fuel and air electrodes.