Chrome Poisoning of Non-Manganiferous Cathode Materials in Solid Oxide Fuel Cells (SOFCs)

Abstract

This work is focused on the degradation effect of chrome poisoning on LSCF cathodes for high temperature SOFCs aimed at an increase of the cell durability. Therefore the electrochemical performance of single cells is investigated at open cell voltage (OCV) and polarizations of 0.5, 0.75 and 1 A*cm -2 as well as at temperatures of 900 and 700°C in presence/absence of a chrome source. To identify the cathode related processes of the impedance spectra without anode contributions, symmetrical half cells were tested as well. It is observed that in presence of a chrome source the ohmic as well as the polarization resistances increase. At a temperature of 900 °C and a humidity of 3.5 %, the polarization resistance shows a stronger increase at current densities above 0.75 A*cm -² whereas the polarization resistance remains linear. Furthermore, measurements at 700 °C confirmed that also the operation temperature serves as a factor for accelerated chrome related cell degradation.

A review of Solid Oxide Fuel Cell cathode materials with respect to their resistance to the effects of chromium poisoning

“…Zhao and authors [158,161] have commented on the acceleration of Sr segragation at higher humidities and, as a result, the increased formation of SrCrO 4 under such conditions. Increases in degradation rate at higher humidities are also documented elsewhere [172,173].…”

Boundary Investigation of High-Temperature Co-Electrolysis Towards Direct CO2 Electrolysis

“…The cell was installed in a two-electrode conductivity & impedance spectroscopy Probostat setup (Norwegian Electro Ceramics®, NORECS, Oslo, Norway) with a furnace from the company Carbolite Gero® (Neuhausen, Germany) as described previously. 8 A heating rate of 2 K•min −1 was set to reduce the risk of thermomechanical stress on cell materials. On the anode side, electrical contact with the cell was established with a Pt mesh current collector and on the cathode side with a Ni mesh current collector.…”

High-Temperature Co-Electrolysis: A Versatile Method to Sustainably Produce Tailored Syngas Compositions

“…The cells were placed in a Probostat sample holder (Norwegian Electro Ceramics AS, NorECs) as described previously. 22 The cell is contacted on the air side with a platinum current collector and on the fuel side with a nickel mesh. The cathode and anode gas chambers are separated by ceramic tubes to which the cell is sealed with a gold ring.…”

“…[16][17][18] The aging rate (i.e. decrease in cell potential) under constant load operation and hydrogen as fuel typically lies below 0.3% per 1000 h. 19,20 The underlying processes, responsible for degradation in solid oxide fuel cells (SOFC), are mostly understood [21][22][23] or can be described by a most recently developed quantitative model. 24 For the operation in co-electrolysis mode and under transient mode of operation, however, the durability has not yet been investigated sufficiently.…”