Calculations of release temperature of hydrogen storage materials

Hannes Jónsson*, Finnbogi Oskarsson, Edda S. Aradóttir

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

Hydrogen storage materials used in combination with PEM fuel cells should provide hydrogen gas at around 1 bar when heated up to around 100 degrees Centigrade. This is a highly restrictive requirement. Currently known candidates for reversible, high capacity (over 6% by weight) hydrogen storage, such as sodium alanate, need to be heated to much higher temperature. In computational searches for useful, high capacity hydrogen storage materials, it is, therefore, important to be able to predict accurately the release temperature of the hydrogen gas. We have assessed how well theoretical calculations can predict the release temperature and what level of theory needs to be applied. We find that calculations using DFT with the PBE functional combined with an evaluation of the chemical potential of hydrogen in solid and gas phase using quantum mechanical, harmonic partition functions predict a release temperature of clean MgH2 in very good agreement with experimental measurements. By applying the same method to predict the release temperature of hydrogen gas from the recently discovered Mg7TiH16 material, we get a value of 60 degrees, which indicates that the addition of Ti results in a remarkably large, nearly 200 degree, lowering of the thermodynamic release temperature.

Original languageEnglish
Title of host publicationAbstracts of Papers - 232nd American Chemical Society Meeting and Exposition
Publication statusPublished - 2006
Event232nd American Chemical Society Meeting and Exposition - San Francisco, CA, United States
Duration: 10 Sept 200614 Sept 2006

Publication series

NameACS National Meeting Book of Abstracts
Volume232
ISSN (Print)0065-7727

Conference

Conference232nd American Chemical Society Meeting and Exposition
Country/TerritoryUnited States
CitySan Francisco, CA
Period10/09/0614/09/06

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