In the architecture of Solid Oxide Fuel Cells (SOFC) and Solid Oxide Electrolysis Cells (SOEC), LSCF/GDC composite powder is the industry-standard material for the "Intermediate Temperature" oxygen electrode. By combining Lanthanum Strontium Cobalt Ferrite (LSCF) with Gadolinium-Doped Ceria (GDC), researchers create a high-performance electrode optimized for operation between 550°C and 750°C.

LSCF is a Mixed Ionic-Electronic Conductor (MIEC), meaning it can transport both electrons and oxygen ions through its crystal lattice. However, it is almost always mixed with GDC to form a composite for several critical reasons: (1) Expanded Reaction Zone: While pure LSCF is an MIEC, adding GDC (a superior ionic conductor) creates a 3D network of "ionic highways." This significantly increases the density of active sites where oxygen is reduced or evolved. (2) Thermal Expansion Matching: Pure LSCF has a higher thermal expansion coefficient (TEC) than common electrolytes like YSZ. Adding GDC—which has a lower TEC—helps "bridge the gap," preventing the electrode from delaminating or cracking during thermal cycling. (3) Adhesion: GDC acts as a chemical and mechanical "glue" between the LSCF catalyst and the GDC barrier layer of the cell.

References:

1. M. Izuki, et al., Interfacial stability and cation diffusion across the LSCF/GDC interface, J. Power Sources, 2011, 196, 7232-7236.
2. Ӧ. Çelikbilek, et al., Influence of sintering temperature on morphology and electrochemical performance of LSCF/GDC composite films as efficient cathode for SOFC, Electrochimica Acta, 2017, 246, 1248-1258.