Fabrication and electrochemical performance analysis of nanocomposite for low-temperature SOFC

Yifu Jing

Research output: ThesisDoctoral ThesisCollection of Articles

Abstract

Low-temperature solid oxide fuel cell (LTSOFC) offers a promising new energy conversion technology, which converts chemical energy into electrical energy. The benefits of LTSOFC technology include a low operating temperature, relatively high energy conversion efficiency, and potentially low costs. One of the key challenges with LTSOFC, however, is the power density and the ionic conductivity of the electrolyte, which still needs improvement. In this work, 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 the LTSOFC fuel cell. As the base electrolyte material, samarium-doped ceria (SDC) was employed, which was also modified by adding a carbonate element (CSDC). A LiNiCuZn electrode composite was utilized, which was synthesized using the slurry method. The ionic conductivity of the electrolyte could be improved via the freeze-drying and SPS methods as opposed to the co-precipitation method. The cold-pressing and hot-pressing methods were separately applied to prepare laboratory unit cells of the LTSOFC with the following results. 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. The power density was improved by 30–100% and the OCV by 0.1–0.2 V compared to using pure air as an oxidant.
Translated title of the contributionFabrication and electrochemical performance analysis of nanocomposite for low-temperature SOFC
Original languageEnglish
QualificationDoctor's degree
Awarding Institution
  • Aalto University
Supervisors/Advisors
  • Lund, Peter, Supervising Professor
  • Zhu, Bin, Thesis Advisor
Publisher
Print ISBNs978-952-60-7538-9
Electronic ISBNs978-952-60-7537-2
Publication statusPublished - 2017
MoE publication typeG5 Doctoral dissertation (article)

Keywords

  • fuel cells
  • low-temperature SOFC
  • nanocomposite
  • ionic conductivity
  • hydrogen

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