What is it about?

Low ionic conductivity and slow reaction kinetics often limit the performance of a ceramic nanocomposite fuel cell (CNFC). Here, we report a novel synthesis method, freeze-dried method, to achieve a record high ionic conductivity for nanocomposite electrolytes (>0.5 S/cm) based on Ce0.85Sm0.15O2 (SDC) and a eutectic mixture of Na2CO3, Li2CO3, K2CO3 (NLK). The highest ionic conductivity (0.55 S/cm) was reached by increasing the carbonate content of the electrolyte to 35 wt%. For the sake of comparison, the nanocomposite electrolytes were also prepared through solid-route. Composite anodes and cathodes for complete fuels were prepared from NiO and La0.6Sr0.4Co0.2Fe0.8O3 (LSCF), respectively using both solid-route and freeze-dried nanocomposite electrolytes. Complete fuel cells manufactured from these nanocomposite materials produced ∼1.1 W/cm² at 550 °C. The EIS measurements revealed low ohmic losses (0.18 Ω cm²) and even lower charge transfer resistance (0.05 Ω cm²). In addition, it was found that the open-circuit-voltage (OCV) of the CNFCs improved from 1.1 V to 1.2 V when a mixture of air and CO2 was supplied as compared to the case when only air was supplied at the cathode. Finally, high temperature X-ray diffraction (HT-XRD) revealed stable structures of SDC, NiO and LSCF up to 600 °C, which shows the thermal stability of these fuel cell materials. Advanced low-temperature ceramic nanocomposite fuel cells using ultra high ionic conductivity electrolytes synthesized through freeze-dried method and solid-route. Available from: https://www.researchgate.net/publication/318925592_Advanced_low-temperature_ceramic_nanocomposite_fuel_cells_using_ultra_high_ionic_conductivity_electrolytes_synthesized_through_freeze-dried_method_and_solid-route [accessed Sep 7, 2017].

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Why is it important?

A record high ionic conductivity for nanocomposite electrolytes (>0.5 S/cm). This could pave the way for fuel cells in the 2 W/cm2 range.

Perspectives

The ionic conductivity achieved with SDC+carbonates is excellent. We try now to turn this to a record high power density

Professor Peter D. Lund
Aalto University

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This page is a summary of: Advanced low-temperature ceramic nanocomposite fuel cells using ultra high ionic conductivity electrolytes synthesized through freeze-dried method and solid-route, Materials Today Energy, September 2017, Elsevier,
DOI: 10.1016/j.mtener.2017.07.017.
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