Fabrication and characterization of symmetrically tubular LSCM-based composite solid oxide electrolyzer cell

Abstract

The need for alternatives to fossil fuels has turned the world’s attention to renewable energies, which are clean, green and non-depletable. As renewable energy generation is intermittent, it requires a form of energy storage such as chemical energy storage in the form of hydrogen gas, H2. One energy storage system that utilizes hydrogen gas well is the Reversible Solid Oxide Cell (RSOC), which works in Solid Oxide Electrolyzer Cell (SOEC) mode to store excess energy by utilizing it to electrolyze water into H2 gas for storage, and works reversibly in Solid Oxide Fuel Cell (SOFC) mode to produce electricity by consuming H2 gas when required. Being able to work reversibly would significantly reduce fabrication material consumption and operational costs. The current issue with SOECs is the material used in the fuel and air electrodes. Conventional fuel electrode that utilizes Nickel / Yttria stabilised zirconia (Ni/YSZ) material faces the issue of oxidization of nickel (Ni), whose compounds blocks the triple phase boundary (TPB) area crucial for the reactions to take place at the fuel electrode. Air electrodes utilizing LSM – based compounds also faces the issue of a lack of TPB due to low ionic conductivity. This issue motivates us to continue developing and performing long term testing of symmetrical SOCs with La0.75Sr0.25Cr0.5Mn0.5O3-δ / Yttria stabilised zirconia (LSCM/YSZ) as the fuel and air electrode, as they have properties that are well-suited, such as chemical stability in redox environment and mechanical stability in high temperatures.