Conducting Property and Performance Evaluation of LNF as Cathode Current Contact Layer in Solid Oxide Fuel Cell

Abstract

Electrical performance, durability and degradations are challenging issues for Solid Oxide Fuel Cell (SOFC) commercialization. Ce0.9Gd0.1O2-δ (GDC) and La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) are current gold material system in SOFC, which mainly works as barrier layer and cathode, respectively. However, the porous GDC barrier layer and vulnerable cathode/electrolyte interface often leads to high ohmic resistances and fast degradations. Herein, we develop and report a novel approach for barrier layer and cathode modifications, using cost-competitive and scalable hydrothermal reaction.Results show that, the as-sintered porous GDC barrier layer is filled up with in-situly grown Ceria based nano particles during hydrothermal reaction, yielding improved density and sintering-active surface, simultaneously. After co-sintered with cathode, the cell obtains optimized cathode/barrier layer interface, exhibiting decreased ohmic and cathode polarization resistances with higher electrical performance and less degradation.On the other aspect, the Ceria based nano particles are also observed in-situly precipitated on LSCF powder surface during hydrothermal reaction, forming dual-phase LSCF@GDC cathode, which also yields decreased ohmic and polarization resistance than pristine LSCF.Above results suggest that hydrothermal modifications are effective for barrier layer and cathode/electrolyte interface optimizations. Thus, the improved oxygen ion transfer and interface contact are beneficial for SOFC electrical performance and long-term operation. Furthermore, this hydrothermal modification is applicable in many other surface and interface optimizations.