Defence in the field of advanced energy systems, Yifu Jing, M.Sc.
Title of the dissertation is: Fabrication and electrochemical performance analysis of nanocomposite for low-temperature SOFC
Yifu Jing, M.Sc., will defend the dissertation "Fabrication and electrochemical performance analysis of nanocomposite for low-temperature SOFC" on 29 September 2017 at 12 noon in Aalto University School of Science, lecture hall M1, Otakaari 1, Espoo. In the dissertation, low-temperature solid oxide fuel cells were improved through better fabrication processes. The best fuel cell developed reached a 1 W/cm2 power density at 470 C.
The thesis deals with low-temperature solid oxide fuel cells (LTSOFC), which convert chemical energy into electrical energy. The benefits of LTSOFC is a low operating temperature, relatively high energy conversion efficiency, and potentially low costs. Key challenges with LTSOFC is the power density and the ionic conductivity of the electrolyte.
In this thesis, several different synthetic and fabrication processes, such as co-precipitation synthesis, freeze-drying synthesis, and spark plasma sintering (SPS) techniques, were employed to enhance the performance of the composite electrolyte for LTSOFC. Samarium-doped ceria (SDC) was employed, which was also modified by adding a carbonate element (CSDC). A LiNiCuZn electrode composite was utilized. The ionic conductivity of the electrolyte could be improved via freeze-drying and SPS methods as opposed to the co-precipitation method. The highest power density obtained was 1 W/cm2 at 470 oC. The best ionic conductivities were obtained by freeze-drying and the SPS, which exceeded 0.4 S/cm. In a carbonate-SDC electrolyte, adding CO2 to the air oxidant clearly improved the power density and the open circuit voltage of the fuel cell.
Dissertation release (pdf)
Opponent: Professor Yongdan Li, Tianjin University, China
Custos: Professor Peter Lund, Aalto University School of Science, Department of Applied Physics
Electronic dissertation: http://urn.fi/URN:ISBN:978-952-60-7537-2