Biomass Fuels for Direct Carbon Fuel Cell with Solid Oxide Electrolyte

Direct carbon fuel cells with solid oxide electrolyte (DC-SOFC) has attracted growing attention recently as an efficient generator of electricity. Moreover, the DC-SOFC can be acknowledged to devices that take advantage of RES, provided it is fed with biomass fuel. In this work, the comprehensive studies performed for various types of DC-SOFCs supplied with charcoals and pyrolyzed in situ wood-chips are presented. Firstly, the samples of fuels were characterized by ultimate analysis, XRD, XPS spectroscopy and thermal analysis (DTA/DSC-TG). These studies showed that the charcoal samples had high carbon, low sulphur and very low ash contents. Although the analyses also confirmed the presence of graphite-like phase in the samples, their structure was highly defected and contained amorphous C. Then, the characteristics of small (2 cm(2)), laboratory DCFCs fed with biomass fuels were determined and analyzed. On the basis of these measurements, the influences of structural, physical and chemical properties of fuels on the performance of fuel cells were evaluated. Five different types of fuels cells were used in these studies; they were constructed from the same solid electrolyte (8YSZ) and LSM-GDC composite cathode but varied in material of anode. The tests performed with these fuel cells showed that: (1) charcoals are suitable and attractive fuels for the DC-SOFC providing sufficiently high power density and (2) one of the possible ways of improving the DCFC parameters is the application of new anode materials which are good catalysts for the Boudouard reaction and resistant against possible chemical degradation. Results of tests with larger DCFCs of dimensions 5 cm x 5 cm fed with charcoal fuel are also presented in the article.