A symmetrical LSCF $(La_{0.6}Sr_{0.4}Co_{0.2}Fe_{0.8}O_{3-delta});ScSZ(89ZrO_2-10Sc_2O_3-1CeO_2)/LSCF$ electrochemical cell with a GDC (Gadolinium-Doped Ceria, $90CeO_2-10Gd_2O_3$) interlayer that was inserted between the LSCF cathode and ScSZ electrolyte was fabricated, and the electrochemical performance of these cells was evaluated. The GDC interlayer was deposited on a ScSZ electrolyte using a screen-printing technique. The GDC interlayer prevented the unfavorable solid-state reactions at the LSCF/ScSZ interfaces. The LSCF cathode on the GDC interlayer had excellent electrocatalytic performance even at $650^{circ}C$. The Area Specific Resistance (ASR) was strongly dependent on the thickness and heat-treatment temperature of the GDC interlayer. The impedance spectra showed that the cell with a $15~27{mu}m$ thick GDC interlayer heat-treated at $1200^{circ}C$ had the lowest ASR.