Thermal destabilization of binary and complex metal hydrides by chemical reaction: A thermodynamic analysis

Author:

Young Whan Cho   Jae-Hyeok Shim   Byeong-Joo Lee  

Journal:

CALPHAD: Computer Coupling of Phase Diagrams and Thermochemistry

Issue Date:

2006

Abstract(summary):

Some alkali and alkali-earth metal hydrides and their complex hydrides have very high hydrogen storage capacities and reversibility. Unfortunately, most of them have decomposition temperatures that are too high. This must be overcome before these hydrides can be considered seriously as practical hydrogen storage materials for on-board applications. In the present study, the CALPHAD approach has been adopted to evaluate thermodynamically the possibility of destabilizing these high temperature binary ionic hydrides and ternary complex hydrides by reacting them with light elements or other hydrides. The MgH 2+Si, LiBH 4+MgH 2, and LiBH 4+Al systems are predicted to show a significant decrease in decomposition temperature. On the other hand, the decrease in the decomposition temperatures of the MgH 2+Al and NaBH 4+Al systems is relatively small. The LiH+Si system also presents a considerable destabilization effect, which is consistent with experiment. [All rights reserved Elsevier]

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