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

JOURNAL OF ALLOYS AND COMPOUNDS

卷:645

Article; Proceedings Paper

Hayes, Jalaal¹  Durojaiye, Tolulope¹  Goudy, Andrew¹ 

[1] Delaware State Univ, Dept Chem, Dover, DE 19901 USA

关键词: Hydrogen storage;    Lithium amide;    Rubidium hydride;    Absorption kinetics;    Cycling;    Thermodynamics;   

DOI  :  10.1016/j.jallcom.2014.12.074

来源: Elsevier

【 摘 要 】

In this study, thermodynamic and kinetic properties of RbH doped 2LiNH(2)/MgH2 were measured and compared for hydrogen absorption and desorption. Pressure-composition-temperature isotherms were obtained in the 150-180 degrees C temperature range and were used to construct van't Hoff plots. The results showed that the absorption enthalpy, 39.7 kJ mol(-1), was less than the desorption enthalpy, 43 kJ mol(-1). Kinetics measurements, done at 160 degrees 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 degrees 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. (C) 2014 Elsevier B.V. All rights reserved.

【 授权许可】

Free