Preparation and characterization of La0.75Sr0.25Cr0.5Mn0.5O3−δ-yttria stabilized zirconia cathode supported solid oxide electrolysis cells for hydrogen generation

Abstract

La0.75Sr0.25Cr0.5Mn0.5O3−δ (LSCM)-YSZ cathode supported solid oxide electrolysis cells (SOECs), with the LSM-YSZ|YSZ|LSCM-YSZ configuration, have been prepared and evaluated for high temperature hydrogen generation. Electrochemical impedance spectra (EIS) and voltage–current curves were recorded out to characterize the cell performance. EIS results showed that the cell resistance increased as the proportion of steam in the feed supply increased, at open circuit voltage. The hydrogen generation rate calculated from Faraday's law is 561mlcm−2h−1 at 850°C with 80vol.% absolute humidity (AH) at a 1.6V electrolysis voltage. Although there is a 8.2% increase of the applied electrolysis voltage, the cell has endured a test lasting more than 103h with 45vol.% AH and 0.33Acm−2 electrolysis current density at 850°C. Energy-dispersive X-ray (EDX) spectroscopy analysis showed that there is no elemental diffusion between the electrode and electrolyte interface after the durability test. Scanning electron microscopy (SEM) images indicate that the slight split between the LSCM-YSZ cathode and the YSZ electrolyte is responsible for the increase of ohmic resistance of the cell; this resistance rise led to the degradation of the cell performance.