LSGM계 음극지지형 고체산화물 연료전지에 적용된 LDC 완충층의 효과

Abstract

LSGM(La0.5Sr0.2Ga0.8Mg0.2 O3-δ) is the very promising electrolyte material for lower-temperature operation of SOFCs, especially when realized in anode-supported cells. But it is notorious for reacting with other cell components and resulting in the highly resistive reaction phases detrimental to cell performance. LDC(La0.4Ce0.6O1.8), which is known to keep the interfacial stability between LSGM electrolyte and anode, was adopted in the anode-supported cell, and its effect on the interfacial reactivity and electrochemical performance of the cell was investigated. No severe interfacial reaction and corresponding resistive secondary phase was found in the cell with LDC buffer layer, and this is due to its ability to sustain the La chemical potential in LSGM. The cell exhibited the open circuit voltage of 0.64 V, the maximum power density of 223 mW/cm2, and the ohmic resistance of 0.17 Ωcm2 at 700°C. These values were much improved compared with those from the cell without any buffer layer, which implies that formation of the resistive reaction phases in LSGM and then deterioration of the cell performance is resulted mainly from the La diffusion from LSGM electrolyte to anode.