Characterization of LaNi4.70Al0.30 handled in air and application to a scheme of thermal compression of hydrogen

LaNi4.70Al0.30 was characterized by SEM, EDS and XRD. The structure was refined by the Rietveld method. The intermetallic stability temperature range in air was analyzed by DSC. The intermetallic is destabilized at T > 160° C. The intermetallic was annealed at this temperature for 24 h in air. After that, the pressure-composition-isotherms were measured. The thermodynamic properties were calculated from the Van’t Hoff diagrams. Values obtained were ΔHf = 30 ± 2 kJ/mol and ΔSf = 0.13 ± 0.01 kJ/mol for absorption process and ΔHd = 31 ± 2 kJ/mol and ΔSd = 0.14 ± 0.01 ± kJ/mol for desorption process. From these results, a scheme of thermal compression of hydrogen (TCH) was proposed. The scheme has a practical compression ratio (Rc) of 7.2 in the 25–100 °C temperature range and 1–1000 kPa pressure range.

► LaNi4.70Al0.30 is handled in air and used in thermal compression of hydrogen scheme. ► The maximum temperature of stability in air of the intermetallic is found. ► A practical compression ratio (Rcp) of 7.2 is obtained.