Wednesday, 16 May 2018: 15:20
Room 307 (Washington State Convention Center)
Doped ceria-carbonates composites are a new class of electrolytes for low temperature solid oxide fuel cells, these show very high ionic conductivity due to fast interfacial transport [1-2]. As reported by Chockalingum and Basu [3], 25 wt% (LiNa)2CO3-GDC electrolyte exibited an ionic conductivity of 0.17 S cm−1 at 550 °C and lowest activation energy of 0.127 eV in the temperature range 550–800 °C. To further improve the ionic conductivity, a series of calcium gadolinium/neodymium/samarium co-doped cerium oxide, M0.2CaxCe0.8-xO2 (x = 0.01 to x = 0.1) (M= Gd, Nd, Sm) have been synthesised by solgel method. The electrolytes have been physically and electrochemically characterized with respect to their thermal behaviour, phase, microstructure, elemental analysis and electrochemical performance using thermogravimetric analysis, X-ray diffraction (XRD), scanning electron microscopy, Transmission electron microscopy (TEM), Energy-dispersive X-ray spectroscopy and electrochemical impedance spectroscopy respectively. The particle size of as synthesized electrolyte powders is ~ 20 nm as observed from the TEM. XRD results of the prepared electrolytes show that the powders are phase pure. The gadolinium calcium co-doped ceria lithium sodium carbonate (25% (LiNa)2CO3-Gd0.2Ca0.05Ce0.75O2) composite electrolytes exhibit high ionic conductivity (0.3 Scm-1 at 650°C), as it combines both the advantages of co-doping and the composite effect. Co-doped composite electrolytes show higher conductivity and stability due to the presence of calcium than the previously investigated composite electrolytes of (LiNa)2CO3-GDC [4, 5].
References
[1] L. Fan, C. Wang, M. Chen, B. Zhu, J. of Power Sources, 234, 154 (2013).
[2] R. Raza, H. Qin, L. Fan, K. Takerda, M. Mizuhata, B. Zhu, J. of Power Sources, 201, 121 (2012).
[3] R. Chockalingam and S. Basu, J. Hydrogen Energ., 36,14977 (2011).
[4] I. Khan, M.I. Asghar, P.D. Lund, S. Basu, J. Hydrogen Energ., Volume 42, 20904 (2017).
[5] I. Khan, P.K. Tiwari, S. Basu, S. Ionics (2017), doi.org/10.1007/s11581-017-2184-9.