Relationship between electrochemical properties of SOFC cathode and composition of oxide layer formed on metallic interconnects

Effect of cathode and electrolyte transport properties on chromium poisoning in solid oxide fuel cells

“…The chromium transport occurs primarily through the formation of Cr 6+ -containing species, such as CrO 3 or CrO 2 (OH) 2 , from oxidation of chromium oxide in the interconnect [9][10][11][12][13][14][15][16][17]. Chromium poisoning has been observed in chromium-based [18,19], nickel-based [20][21][22][23] and iron-based [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] interconnect alloys, so that one of the objectives in the design of new alloys for SOFC interconnects is to reduce scale volatilization. One alloying addition used to reduce volatilization is manganese, which is incorporated in the oxide scale and leads to the formation of a (Mn,Cr) 3 O 4 spinel layer on the scale surface.…”

“…Chromium poisoning is generally associated with cathodic polarization and thus has been attributed to electrochemical reduction of the chromium-containing gas species to form Cr 2 O 3 on the cathode [18][19][20][21][22][23][24][25][26][27][28][29][30] by either,…”

Degradation of (La0.6Sr0.4)0.95(Co0.2Fe0.8)O3−δ Solid Oxide Fuel Cell Cathodes at the Nanometer Scale and below

“…Studies on the mechanisms of Cr deposition have proposed that the process is a chemical reaction between Cr (VI) with active elements in the electrode material such as Sr in LSCF [8][9] , more than an electrochemical reduction process in competition with O2 reduction [10][11] . The Cr rich phases, in the case of LSCF, have been suggested to be mainly SrCrO4 with a minor Cr2O3 impurity from bulk analysis using X-ray diffraction (XRD) and scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDX) 8,[12][13] . Many studies have reported that Cr deposition tends to occur at the LSCF surface 6,[8][9]12 , in contrast to LSM where the Cr deposition is concentrated at the LSM/electrolyte interface 9,14 .…”

Conductivity and oxygen reduction activity changes in lanthanum strontium manganite upon low-level chromium substitution

“…Numerous studies (e.g. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]) have considered the severity of chromium poisoning of (La,Sr)MnO 3 -based cathodes depending on whether the SOFC is operated under load or is held at open-circuit, whether the air supplied to the cathode is dry or humidified, and depending on the interconnect metallic alloy used (Inconel 600, Cr5Fe1Y 2 O 3 , Crofer22APU, RA446, 17-4 stainless steel, AISI 441, SUS430, ITM or ZMG232).…”