Characterization and Testing of Exsolution-Based Solid Oxide Cells for Reversible Operations in CO2 Electrolysis

Abstract

Reversible solid oxide cells (rSOCs) are promising electrochemical devices, able to work both in energy storage mode as solid oxide electrolyzes (SOECs), and in power generation mode as solid oxide fuel cells (SOFCs). rSOCs dedicated to high-temperature co-electrolysis of CO2/H2O mixtures are of interest since they could foster the utilization and consequent reduction of CO2 gas emissions while converting it and H2O into valuable fuels (i.e. syngas and H2). However, operation under CO2-rich feeds requires alternatives to the state-of-the-art Ni-Yttria-stabilized-zirconia (Ni-YSZ) cermet fuel electrode in view of its low coking and redox resistance. Perovskites with mixed ionic and electronic conductivity are major alternatives, especially when the functionality of their active surface is enhanced via metal nanoparticle exsolution. This work focuses on the investigation of the electrocatalytic properties of the SrTi0.3Fe0.7O3 (STF), and exsolution Sr0.95(Ti0.3Fe0.63Ni0.07)O3 (STF-Ni) perovskite-based fuel electrodes together with Ni-YSZ while operating with CO2-rich mixtures both in the short and long term.