Deposit of dense YSZ electrolyte and porous NiO–YSZ anode for SOFC device by a low pressure plasma process

A low pressure plasma process was used in the laboratory to synthesize very pure Sr-doped LaMnO3 porous layers, which could be used as a SOFC cathode. Recent experimental work allowed to adapt the process to synthesize both the YSZ dense electrolyte and the NiO–YSZ porous anode in one step. The raw material was a mixture of Y and ZrO nitrates dissolved in water. Nitrates were introduced in the argon/oxygen plasma discharge in order to obtain on a quartz substrate a very pure YSZ layer at low temperature (T ≤ 360 K). After depositing YSZ as a layer, Ni nitrates were progressively added to the mixture of Y and ZrO nitrates in order to obtain a NiO–YSZ layer presenting concentration gradients. SEM-EDX analyses were performed on the fractured cross section of the YSZ/NiO–YSZ/NiO stack. Micrographs showed that the YSZ layer is dense, contrary to the porous NiO–YSZ and NiO ones. EDX analyses confirmed the purity and the composition of the YSZ layer. The presence of concentration gradients of Ni and YSZ along the cross section was demonstrated: contrary to the YSZ concentration, the Ni one increases from the YSZ layer up to the surface. No Y and Zr elements were detected at the surface of the YSZ/NiO–YSZ/NiO stack.