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  • 03월 05일 13시 이후 : 초록수정 불가능, 일정확인 및 검색만 가능

대한화학회 제105회 학술발표회 및 총회 Thermodynamic and Electrical Characteritics of NdBaCo2O5+δ in a Reducing Environment

2010년 2월 17일 11시 17분 15초
39P202포 이곳을 클릭하시면 발표코드에 대한 설명을 보실 수 있습니다.
금 <발표Ⅳ>
저자 및
유선영, 신지영1, 김건태
울산과학기술대학교 친환경에너지공학부, Korea
1동의대학교 기계공학과, Korea

Solid oxide fuel cell is the device that converts the chemical energy in fuel to the electrical energy directly with high efficiency. Cation ordered perovskite-related oxides, NdBaCo2O5+δ(NBCO), is known as one of the best cathode materials for intermediate-temperature solid oxide fuel cell(IT-SOFC) because of its rapid oxygen diffusion and surface exchange kinetics and high electrical conductivity. The purpose of redox characteristics is to identify the above properties of the NdBaCo2O5+δ as a candidate for IT-SOFC cathode material with the appropriate experimental techniques, such as XRD, 4-probe conductivity, and coulometric titration(CT). Thermodynamic redox characteristics including oxidation enthalpies and entropies were studied by the CT. The isotherms were obtained at 650, 700 and 750℃ over a broad range of pO2. Oxygen non-stoichiometry has shown that higher temperature lead more reduction of the NBCO at the same pO2 region, involving that its decomposition at 750℃ occurred near the pO2 of 10-5atm, but it was not detected at 650℃ within the operational range of the SOFC cathode (pO2 of 10-5atm). Therefore, the NBCO may not be suitable for the cathode of SOFC above operating temperature of 750℃ due to the decomposition. The oxidation enthalpies increased quite a lot even with small change in the reduction state, which were -338.2 kJ/mol-O2 and -506.0 kJ/mol-O2 at δ=0.412 and 0.392, respectively. Also the oxidation entropies were determined as -305.3 J/mol-O2/K and -469.0 J/mol-O2/K at δ=0.412 and 0.392, respectively. The electrical conductivities were measured by 4-probe method over a broad range of pO2. This material indicated sufficiently high conductivities for IT-SOFC cathode application.