[기계] Nanoscale Ceramic Fuel Cells for Low Temperature Operation

1. 제목 : Nanoscale Ceramic Fuel Cells for Low Temperature Operation

2. 일시 : 2009년 5월 25일 월요일 오후 4시

3. 장소 : 서울대학교 301동 15층 세미나실 (1512호)

4. 연사 : 심준형 박사 (Stanford University)

5. 약력 :
2002 Mechanical Engineering, Seoul National University, B.S.
2004 Mechanical Engineering, Stanford University, M.S.
2008 Mechanical Engineering, Stanford University, Ph.D.

6. 내용요약 : The ceramic fuel cell (CFC) refers to fuel cells employing solid state ceramic electrolytes, including two types of fuel cells: the solid oxide fuel cell (SOFC) and the proton-conducting oxide fuel cell (PCOFC). Ion conducting ceramics require high operation temperatures of about 700~1000°C for reasonably active charge transfer reactions at the electrode-electrolyte interface and ion transport through the electrolyte. This high operational temperature has limited CFC applications due to thermal instability of equipped devices. The goal of this study is to minimize Ohmic losses and activation losses at the electrolyte and electrode-electrolyte interface respectively by engineering CFC components to run fuel cells at reduced temperatures. Successful synthesis of nano-scale oxide ion-conducting yttria-stabilized zirconia (YSZ) and proton-conducting yttrium-doped barium zirconate (BYZ) was demonstrated using atomic layer deposition (ALD) and pulsed laser deposition (PLD). Fuel cells with 60nm ALD YSZ showed maximum power densities of 30~600mW/cm2 at 265~450°C respectively. Performance enhancement originated from an increase in exchange current density at the electrode-electrolyte interface. Fuel cells with 130nm thick PLD BYZ electrolytes were also successfully fabricated and the best performing PLD BYZ cells exhibited a maximum power density of 10~120mW/cm2 at 300~450°C. As an alternative to PLD BYZ, a 110 nm thick ALD BYZ electrolyte was tested to enhance the overall performance. The best performing ALD BYZ cells showed a maximum power density of 15~140mW/cm2 at 300~400°C.

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