Details

Autor(en) / Beteiligte

• Hayes, Jalaal
• Durojaiye, Tolulope
• Goudy, Andrew

Titel

Hydriding and dehydriding kinetics of RbH-doped 2LiNH2/MgH2 hydrogen storage system

Ist Teil von

• Journal of alloys and compounds, 2015-10, Vol.645 (S1), p.S496-S499

Ort / Verlag

Netherlands: Elsevier B.V

Erscheinungsjahr

2015

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• [Display omitted] •The amount of hysteresis in RbH doped 2LiNH2/MgH2 increases with cycling.•The absorption enthalpy is less than the desorption enthalpy (39.7 vs 43kJmol−1).•The rate of H2 absorption is approximately twice as fast as desorption.•Diffusion is the rate-limiting process for both H2 absorption and desorption. In this study, thermodynamic and kinetic properties of RbH doped 2LiNH2/MgH2 were measured and compared for hydrogen absorption and desorption. Pressure–composition–temperature isotherms were obtained in the 150–180°C temperature range and were used to construct van’t Hoff plots. The results showed that the absorption enthalpy, 39.7kJmol−1, was less than the desorption enthalpy, 43kJmol−1. Kinetics measurements, done at 160°C using constant pressure thermodynamic driving forces, show that under the same conditions, absorption is approximately twice as fast as desorption. Modeling studies, based on a shrinking core model, show that diffusion is the rate-limiting process for both absorption and desorption. Cycling studies were also done to determine if any changes would occur in the sample upon repeated hydriding/dehydriding at 200°C. It was found that the amount of hysteresis increased and there was also about a 30% decrease in the hydrogen capacity after 70 cycles.