Transport through mixed proton, oxygen ion and electron/hole conductors: Analysis of fuel cells and electrolyzer cells using Onsager equations

Improved stability of reversible solid oxide cells with a nickelate-based oxygen electrode

“…Oxygen accumulation creates a barrier to the transport of gas and can even lead to rupture of the cells. 49 However, this oxygen excess can accommodate itself into the PNO phase as previously reported in other Ruddlesden-Popper compounds. 10,11,44 In our opinion, this is probably the reason for the outstanding enhancement in the performance of these novel cells in the electrolysis mode.…”

Thermodynamic analysis of the electrochemical synthesis of ammonia in solid-state proton-conducting electrochemical reactors considering interfacial potential steps

“…As shown in eqn ( 17) and ( 18), during the operation of the PCER, the hydrogen partial pressure at the electrode-electrolyte interface layer could change abruptly, which is caused by the driving force of the electrode reaction (DE). Similar conclusions have been reported in theoretical 23,24,32 and experimental 27,33 studies.…”

“…It is worth mentioning that the effect of applied voltage/ current on the chemical potential/partial pressure of gas species within oxygen-ion conducting solid membranes has been studied theoretically [22][23][24][25] and demonstrated experimentally. [26][27][28] In terms of theoretical studies, Virkar [22][23][24] has reported that under certain operating conditions, the chemical potential/ partial pressure of oxygen within the electrolyte may lie out of bounds in relationship to values at the electrodes and high oxygen pressure could develop in the electrolyte just near the electrode-electrolyte interface, leading to oxygen electrode delamination. Chen et al 27 have experimentally demonstrated that high oxygen activity (up to 280 atm) could be achieved at the Pr 0.1 Ce 0.9 O 2Àd /Y 2 O 3 stabilized ZrO 2 interface by controlling the voltage bias.…”

“…The interfacial effect between the electrolyte and electrode on the properties of solid electrolytes has been investigated theoretically [22][23][24][25] and experimentally. [26][27][28] For theoretical studies, Virkar [22][23][24] has developed mathematical models and reported that under the operating conditions, the chemical potential/ partial pressure of gas species may lie out of bounds in relation to values at the electrodes, which is due to the interfacial effects. Kawada et al 25 have developed a model based on an equivalent circuit and found that the oxygen vacancy concentration/effective oxygen chemical potential at the electrode/electrolyte interface could be controlled by voltage bias.…”

Progress Report on Proton Conducting Solid Oxide Electrolysis Cells

“…The transport behavior of all charged defects across the air electrode/electrolyte and fuel electrode/electrolyte interfaces is incorporated into the analysis of this model. Virkar [87] has also used Onsager equations and equivalent circuits to describe the motion of charged defects in mixed conductors in the electrolysis mode. The Onsager equation can be written as: […”