[Liu, Chang; Li, Feng; Ma, Lai-Peng; Cheng, Hui-Ming] Chinese Acad Sci, Inst Met Res, Shenyang Natl Lab Mat Sci, Shenyang 110016, Peoples R China.;Cheng, HM (reprint author), Chinese Acad Sci, Inst Met Res, Shenyang Natl Lab Mat Sci, 72 Wenhua Rd, Shenyang 110016, Peoples R China;cheng@imr.ac.cn

Advanced Materials for Energy Storage

Metal hydride materials for solid hydrogen storage: a review

Note: Times Cited: 875 Reference EPFL-ARTICLE-206025doi:10.1021/cr0501846View record in Web of Science URL: ://WOS:000249839900009 Record created on 2015-03-03, modified on 2017-05-12

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Complex hydrides for hydrogen storage.

Complex Hydrides for Hydrogen Storage

This review focuses on key aspects of the thermal decomposition of multinary or mixed hydride materials, with a particular emphasis on the rational control and chemical tuning of the strategically important thermal decomposition temperature of such hydrides, Tdec. An attempt is also made to predict the thermal stability of as-yet unknown, elusive or even unknown hydrides. The future of a particularly promising class of materials for hydrogen storage, namely the catalytically enhanced complex metal hydrides, is discussed. The predictions are supported by thermodynamics considerations, calculations derived from molecular orbital (MO) theory and backed up by simple chemical insights and intuition.

Thermal decomposition of the non-interstitial hydrides for the storage and production of hydrogen.

The pursuit of a clean and healthy environment has stimulated much effort in the development of technologies for the utilization of hydrogen-based energy. A critical issue is the need for practical systems for hydrogen storage, a problem that remains unresolved after several decades of exploration. In this context, the possibility of storing hydrogen in advanced carbon materials has generated considerable interest. But confirmation and a mechanistic understanding of the hydrogen-storage capabilities of these materials still require much work1,2,3,4,5. Our previously published work on hydrogen uptake by alkali-doped carbon nanotubes cannot be reproduced by others6,7,8. It was realized by us and also demonstrated by Pinkerton et al.8 that most of the weight gain was due to moisture, which the alkali oxide picked up from the atmosphere. Here we describe a different material system, lithium nitride, which shows potential as a hydrogen storage medium. Lithium nitride is usually employed as an electrode, or as a starting material for the synthesis of binary or ternary nitrides9,10. Using a variety of techniques, we demonstrate that this compound can also reversibly take up large amounts of hydrogen. Although the temperature required to release the hydrogen at usable pressures is too high for practical application of the present material, we suggest that more investigations are needed, as the metal–N–H system could prove to be a promising route to reversible hydrogen storage.

Interaction of hydrogen with metal nitrides and imides

The safe and efficient storage of hydrogen is widely recognized as one of the key technological challenges in the transition towards a hydrogen-based energy economy. Whereas hydrogen for transportation applications is currently stored using cryogenics or high pressure, there is substantial research and development activity in the use of novel condensed-phase hydride materials. However, the multiple-target criteria accepted as necessary for the successful implementation of such stores have not yet been met by any single material. Ammonia borane, NH3BH3, is one of a number of condensed-phase compounds that have received significant attention because of its reported release of approximately 12 wt% hydrogen at moderate temperatures (approximately 150 degrees C). However, the hydrogen purity suffers from the release of trace quantities of borazine. Here, we report that the related alkali-metal amidoboranes, LiNH2BH3 and NaNH2BH3, release approximately 10.9 wt% and approximately 7.5 wt% hydrogen, respectively, at significantly lower temperatures (approximately 90 degrees C) with no borazine emission. The low-temperature release of a large amount of hydrogen is significant and provides the potential to fulfil many of the principal criteria required for an on-board hydrogen store.

High-capacity hydrogen storage in lithium and sodium amidoboranes

Lithium nitride and imide were found to possess remarkable hydrogen storage capacity under moderate temperatures and pressures [1]. For lithium imide, as an example, ~7wt% of hydrogen can be theoretically absorbed. To release hydrogen at equilibrium pressure of one bar, temperature has to be raised to above 270oC, which is on the higher side for practical application. To lower down the operation temperatures, thermodynamic parameters of the material should be altered. Here we report the recent progresses in the development of ternary imides for hydrogen storage. Binary imide, Li2NH, was modified by adding Ca and Mg in order to form ternary systems. Hydrogen absorption and desorption over these materials were found to take place at much reduced temperatures. For Li-Mg-N-H systems temperature as low as 170 oC was achieved. P-C isotherms of the ternary systems have been determined and the structural changes before and after hydrogen storage were investigated.

Ternary Imides for Hydrogen Storage

Pure lithium amide (LiNH2) decomposes to lithium imide and ammonia at temperatures above 300 °C. Lithium hydride, on the other hand, liberates hydrogen at temperatures above 550 °C. By thoroughly mixing these two substances and conducting temperature-programmed desorption (TPD), we noticed that hydrogen was produced at temperatures around 150 °C. Combined thermogravimetric (TG), X-ray diffraction (XRD), and infrared (IR) analysis revealed that lithium amide would react with lithium hydride and convert to hydrogen and lithium imide (or Li-rich imide). The reaction mechanism was investigated by isotopic exchange.

Zhitao Xiong

Papers

Interaction of hydrogen with metal nitrides and imides

High-capacity hydrogen storage in lithium and sodium amidoboranes

Ternary Imides for Hydrogen Storage

Interaction between Lithium Amide and Lithium Hydride

Thermodynamic and kinetic investigations of the hydrogen storage in the Li–Mg–N–H system