Thermionic emission measurement of sintered lanthanum hexaboride discs and modelling of their solar energy conversion performance

Year: 2021

Authors: Bellucci A., Mastellone M., Girolami M., Serpente V., Sani E., Sciti D., Trucchi D.M.

Autors Affiliation: ISM CNR, Ist Struttura Mat, Sede Secondaria Montelibretti, DiaTHEMA Lab, Via Salaria Km 29-300, I-00015 Monterotondo, RM, Italy; INO CNR, Ist Nazl Ott, Largo E Fermi 6, I-50125 Florence, FI, Italy; ISTEC CNR, Ist Sci & Tecnol Mat Ceram, Via Granarolo 64, I-48018 Faenza, RA, Italy.

Abstract: Polycrystalline lanthanum hexaboride (LaB6) discs were sintered by hot pressing of commercial powders and successively polished, in order to investigate their thermionic emission capability. LaB6 samples presented values of work function in the range 2.55-2.61 eV. Discs with polished surface, independently from the composition and density, demonstrated to provide a Richardson constant around 45 A cm-2 K-2. These results are promising for the use of sintered LaB6 discs in thermionic energy converters operating at temperatures in the 1400-1700 degrees C range. Moreover, since the properties of solar absorption and spectral selectivity of LaB6 make them appealing for the conversion of concentrated solar radiation, a modelling study to estimate the energy conversion efficiency was performed, aimed at identifying the proper engineering strategies able to make the resulting devices competitive for electrical conversion of concentrated solar radiation.

Journal/Review: CERAMICS INTERNATIONAL

Volume: 47 (14)      Pages from: 20736  to: 20739

KeyWords: Thermionic emission
Concentrated solar radiation
Solar-to-electric conversion efficiency
High temperature
Surface properties
DOI: 10.1016/j.ceramint.2021.04.079

Citations: 12
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