Recent Progress in Metal Borohydrides for Hydrogen Storage

Hai-Wen Li,Shin-Ichi Orimo,Yigang Yan,Craig M Jensen,Andreas Züttel

doi:10.3390/en4010185

Abstract

The prerequisite for widespread use of hydrogen as an energy carrier is the development of new materials that can safely store it at high gravimetric and volumetric densities. Metal borohydrides M(BH4)n (n is the valence of metal M), in particular, have high hydrogen density, and are therefore regarded as one such potential hydrogen storage material. For fuel cell vehicles, the goal for on-board storage systems is to achieve reversible store at high density but moderate temperature and hydrogen pressure. To this end, a large amount of effort has been devoted to improvements in their thermodynamic and kinetic aspects. This review provides an overview of recent research activity on various M(BH4)n, with a focus on the fundamental dehydrogenation and rehydrogenation properties and on providing guidance for material design in terms of tailoring thermodynamics and promoting kinetics for hydrogen storage.

Highlights

Development of advanced hydrogen storage materials for onboard hydrogen storage systems is regarded as a key prerequisite for widespread adoption of fuel cell vehicles
The electronic structures indicate that charge transfer from the metal cations Mn+ to the [BH4]− anions is a key feature determining the thermodynamic stability of M(BH4)n [4,5,6,7,8]
We focus on the recent progress in the dehydrogenation and rehydrogenation reactions of M(BH4)n at controlled temperature and hydrogen pressure

Summary

Introduction

Development of advanced hydrogen storage materials for onboard hydrogen storage systems is regarded as a key prerequisite for widespread adoption of fuel cell vehicles. Energies 2011, 4 applications, hydrogen storage materials must possess all the following capabilities: high gravimetric hydrogen density, adequate hydrogenation-dehydrogenation temperature/rate, cycling stability, and low cost [1]. Metal borohydrides M(BH4)n (n indicates the valence of M) have high gravimetric hydrogen densities and have attracted great interest for use in hydrogen storage [2]. The electronic structures indicate that charge transfer from the metal cations Mn+ to the [BH4]− anions is a key feature determining the thermodynamic stability of M(BH4)n [4,5,6,7,8]. Because the hydrolysis reaction is highly irreversible, such materials are certainly not candidates for reversible hydrogen storage. We focus on the recent progress in the dehydrogenation and rehydrogenation reactions of M(BH4)n at controlled temperature and hydrogen pressure. Some several excellent reviews on M(BH4)n are available [2,12,13,14,15,16,17,18]

Fundamentals of Hydrogen Storage Properties

Tailoring Thermodynamics

Promoting Kinetics

Findings

Conclusions