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CO/CO 2 Study of High Performance La 0.3 Sr 0.7 Fe 0.7 Cr 0.3 O 3– δ Reversible SOFC Electrodes
Author(s) -
Addo P. K.,
MoleroSanchez B.,
Chen M.,
Paulson S.,
Birss V.
Publication year - 2015
Publication title -
fuel cells
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.485
H-Index - 69
eISSN - 1615-6854
pISSN - 1615-6846
DOI - 10.1002/fuce.201400196
Subject(s) - electrolysis , cyclic voltammetry , electrode , analytical chemistry (journal) , polarization (electrochemistry) , materials science , oxide , perovskite (structure) , solid oxide fuel cell , electrochemistry , chemistry , anode , metallurgy , electrolyte , crystallography , chromatography
Abstract In this study, we demonstrate that the La 0.3 Sr 0.7 Fe 0.7 Cr 0.3 O 3– δ (LSFCr) perovskite, examined here as a CO/CO 2 fuel electrode material intended for symmetrical, reversible solid oxide fuel cell (RSOFC) applications, is both high performing and stable towards CO 2 electrolysis (SOEC mode) and the oxidation of CO (SOFC mode). To demonstrate this, symmetrical LSFCr/GDC/YSZ/GDC/LSFCr cells were evaluated electrochemically by using both DC (cyclic voltammetry (CV) and galvanostatic) and AC (impedance) techniques. The cells were tested at 800 °C using either 90% CO 2 :10% CO or 70% CO 2 :30% CO at the fuel electrode and air flowing to the O 2 electrode. From the open circuit impedance data, the polarization resistance, measured at 800 °C in a 90% CO 2 :10% CO and 70% CO 2 :30% CO gas composition, was 1.3 Ω cm 2 and 0.9 Ω cm 2 , respectively. Both the CV and polarized impedance data showed that the cell performance is higher during the electrolysis of CO 2 than for the oxidation of CO. Furthermore, the cell showed a very stable activity during CO 2 electrolysis, with a degradation rate of only 0.057 mV h −1 after ca. 135 h of galvanostatic testing at –100 mA cm −2 in 90% CO 2 :10% CO at 800 °C.