Browsing by Author "Zhang, Linlin"

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  • Electrochemical mechanisms of an advanced low-temperature fuel cell with a SrTiO 3 electrolyte
    (2019-04-28) Chen, Gang; Liu, Hailiang; He, Yang; Zhang, Linlin; Asghar, Muhammad Imran; Geng, Shujiang; Lund, Peter D.
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    The electrochemical mechanisms and performance of a symmetrical low-temperature SOFC with a single oxide as the electrolyte are investigated here. The fuel cell has a layered Ni foam-Ni 0.8 Co 0.15 Al 0.05 LiO 2 (NCAL)/SrTiO 3 (STO)/NCAL-Ni foam structure. A 0.8 mm thick layer of STO is used as the electrolyte and NCAL-coated nickel foam is used as the electrode on both sides of the cell. The maximum power densities of the cell were 0.31, 0.44, and 0.62 W cm −2 in a H 2 /air atmosphere at 450, 500, and 550 °C, respectively. The corresponding ionic conductivities of the STO electrolyte were 0.16, 0.21, and 0.24 S cm −1 . Ion filtration experiments with densified Gd-doped CeO 2 /STO and SrCe 0.95 Y 0.05 O 3−δ /STO double layer electrolytes indicated that both oxygen ions and protons act as charge carriers in the STO electrolyte. XPS, TGA, and HRTEM analyses indicate that lithium carbonate, which originates from the NCAL, coats the STO electrolyte and forms a core-shell structure in the fuel cell test atmosphere. Lithium carbonate between the surface and interface of the STO particles may provide a pathway for oxygen ion and proton conduction.
  • Mechanism for Major Improvement in SOFC Electrolyte Conductivity When Using Lithium Compounds as Anode
    (2020-05-26) He, Yang; Chen, Gang; Zhang, Xuebai; Zhang, Linlin; Yang, Di; Asghar, Muhammad Imran; Geng, Shujiang; Lund, Peter D.
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Recent studies indicate that the electrolyte ionic conductivity in an SOFC can be considerably increased by using lithium compounds as the electrode. We found that the ionic conductivity of Gd0.1Ce0.9O1.95 electrolyte in the Ni0.8Co0.15Al0.05LiO2 anode cell was 10.1 mS/cm only at 550 °C without H2, but it increased to 44.6 mS/cm after feeding H2 to the anode. It was found that LiOH/Li2CO3 moved into the GDC electrolyte from the NCAL anode and formed a three-phase composite electrolyte. A space charge region with a high oxygen vacancy concentration is formed around the interface of LiOH/Li2CO3 and GDC, which increases the ionic conductivity.