La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ 공기극과 Sc이 도핑된 지르코니아 전해질 사이에 삽입한 Gd 0.1 Ce 0.9 O 2-δ 중간층이 고체산화물 연료전지의 전기화학적 성능에 미치는 영향

Influence of Gd 0.1 Ce 0.9 O 2-δ Interlayer between La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ Cathode and Sc-doped Zirconia Electrolyte on the Electrochemical Performance of Solid Oxide Fuel Cells

The optimal fabrication conditions for Gd 0.1 Ce 0.9 O 2-δ (GDC) buffer layer and La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ (LSCF) cathode on 1mol% CeO 2 –10mol% Sc 2 O 3 stabilized ZrO 2 (CeScSZ) electrolyte were investigated for application of IT-SOFCs. GDC buffer layer was used in order to prevent undesired chemical reactions between LSCF and CeScSZ. These experiments were carried out with 5 x 5cm 2 anode supported unit cells to investigate the tendencies of electrochemical performance, Microstructure development and interface reaction between LSCF/GDC/CeScSZ along with the variations of GDC buffer layer thickness, sintering temperatures of GDC and LSCF were checked, respectively. Electrochemical performance was analyzed by DC current-voltage measurement and AC impedance spectroscopy. Microstructure and interface reaction were investigated by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Although the interfacial reaction between these materials could not be perfectly inhibited, We found that the cell, in which 6μm GDC interlayer sintered at 1200℃ and LSCF sintered at 1000℃ were applied, showed good interfacial adhesions and effective suppression of Sr, thereby resulting in fairly good performance with power density of 0.71W/cm 2 at 800℃ and 0.7V.