Investigation of Secondary Phases Formation Due to PH ₃ Interaction with SOFC Anode

Phosphine induced Nickel Migration in SOFC Anodes: A Computational Study

“…This will drive the diffusion of Ni from the bulk of the porous anode to the surface. The melting point for some secondary phases that are reported by Marina et al and Guo et al [11,12] is close to the usual cell operating temperature of 800 o C causing them to soften and thus be more conducive for Ni migration. The effect of the current can be approximated as a convective term included by the electro migration mechanism as explained by Popovich et al [16] for electrical and electronic systems.…”

“…However, the mechanism responsible for the experimentally observed Ni migration is still not well understood. The steam concentration has a direct effect on the electro migration [9] and the formation of the secondary phases [7,10,11]. Therefore, the formation of secondary phases and the electro migration due to the applied current seem to be the most reasonable mechanisms, which are possibly responsible for nickel migration.…”

“…Marina et al [12] reported that the most possible species of Ni-P compounds are Ni 3 P, Ni 5 P 2 , Ni 12 P 5 , and Ni 2 P. Nickel conversion to nickel phosphide in the anode was considered to be one possible mechanism of SOFC performance degradation by Marina et al [12]. Guo et al [11] investigated the possible secondary phases formed due to phosphine exposure. Guo et al [11] observed the formation of secondary phases inside the anode and the dominant Pbased phases were found to be nickel phosphates such as Ni(PO 3 ) 2 for a cell under load (e.g.…”

“…Guo et al [11] investigated the possible secondary phases formed due to phosphine exposure. Guo et al [11] observed the formation of secondary phases inside the anode and the dominant Pbased phases were found to be nickel phosphates such as Ni(PO 3 ) 2 for a cell under load (e.g. 0.3V), however under open circuit voltage (OCV) condition the most possible secondary phase was found to be Ni 3 P. Electro migration has been recognized as an important mechanism which may lead to failure in electrical and electronic systems [9,13,14].…”

Refined computational modeling of SOFCs degradation due to trace impurities in coal syngas

“…They operate at relatively high temperatures (~800 o C) leading to the exhaust gas stream conditions that are ideal for use in combined heat and power applications and combined-cycle electric power plants [6,14]. However studies [6,12,15,16,17,18,19,20,21] show that coal syngas operated SOFCs exhibit significant performance losses due to the impurities (phosphine, arsenic, zinc and selenium) in coal syngas.…”