Air electrodes and related degradation mechanisms in solid oxide electrolysis and reversible solid oxide cells

Impact of Praseodymia Additions and Firing Conditions on Structural and Electrical Transport Properties of 5 mol.% Yttria Partially Stabilized Zirconia (5YSZ)

“…Similar transformations of independent variables were assumed to perform multivariate analysis for changes in conductivity and its activation energy, and also for the lattice parameter. This dependence for a generic property Y is given by: ln(Y) = ln(Y 0 ) − m/T f + n ln(t f ) + p ln(Pr), (9) and the relevant coefficients and impact on these properties are shown in Table 6. These values confirm the guidelines provided by the correlation matrix.…”

“…The SOEC technology is currently at moderate TRL (technology readiness level), and long-term degradation remains one of the main challenges obstructing the widespread adoption of solid oxide electrolysis cells as practical hydrogen generation systems. A specific degradation mechanism in SOEC relates to delamination of the oxygen electrode and accompanying processes occurring at the electrolyte/oxygen electrode interface [3,[7][8][9]. The mechanisms of delamination were studied for LSM (La 1-x Sr x MnO 3-δ ), LSFC (La 1-x Sr x Fe 1-y Co y O 3-δ ), and other perovskite-type oxygen electrodes.…”

“…The mechanisms of delamination were studied for LSM (La 1-x Sr x MnO 3-δ ), LSFC (La 1-x Sr x Fe 1-y Co y O 3-δ ), and other perovskite-type oxygen electrodes. The common view is that high oxygen partial pressure buildup within the pores, grain boundaries and other defects in the near-interface electrolyte layer and also at the electrode/electrolyte interface under anodic polarization results in intergranular fractures in the electrolyte surface layer and cracking and delamination at the electrode/electrolyte interface [7][8][9]. These irreversible degradation processes are contributed or promoted by the interdiffusion of cations with the formation of undesired phases at the interface, insufficient ionic conductivity, and, consequently, the electrochemical activity of the oxygen electrode, and other factors.…”

“…The electrochemical studies of rSOCs operation revealed that the degradation occurring at the electrolyte/oxygen electrode interface can be slowed down if a cell operates in a reversible SOEC/SOFC regime and that the degradation occurring in the SOEC regime may be partially recovered during the operation in SOFC mode if the cycles duration does not exceed a certain limit [8][9][10]. Although further long-term studies and fundamental understanding of this phenomenon are still required, the experimental observations raise prospects to halt degradation and to develop self-healing approaches based on reversible SOEC/SOFC cycles [11].…”

Layered Oxygen-Deficient Double Perovskites as Promising Cathode Materials for Solid Oxide Fuel Cells

“…Despite essential progress, which recently has been achieved in the development of individual SOFCs materials (electrolytes, anodes, cathodes, collectors, and sealants) [ 3 , 6 , 7 , 8 , 9 , 10 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 ] and the production and testing of SOFCs [ 1 , 2 , 7 , 21 , 22 , 23 ], some urgent challenges still exist. One of the most important of these challenges is the search for, development of, and study of new electrode materials, which possess high stability, thermal and chemical compatibility, and improved electrochemical performance towards cathode and electrode reactions occurring in SOFCs.…”