Magnesium and Doped Magnesium Nanostructured Materials for Hydrogen Storage - Low-cost Nanomaterials: Toward Greener and More Efficient Energy Applications - page 290

Magnesium and Doped Magnesium
Nanostructured Materials
for Hydrogen Storage

Daniel J. Shissler, Sarah J. Fredrick, Max B. Braun
and Amy L. Prieto

Abstract Hydrogen is an attractive fuel for many applications because of its high
energy density as molecular hydrogen, as well as the clean exhaust produced when
burned with oxygen. One significant challenge to the widespread adoption of
hydrogen, for mobile applications in particular, is the inability to efficiently store
large amounts of readily accessible hydrogen in small volumes at ambient tem-
perature and pressure. This chapter describes the current research on one particu-
larly interesting candidate for hydrogen storage, nanostructured magnesium. The
synthetic methods currently used to control the size and shape of nanostructured
magnesium are described, as are the measured kinetics of hydrogen storage, the
modeling used to explain the observed kinetics, and theoretical models that can be
used to guide experimental efforts.

1 Introduction

Hydrogen is a very attractive fuel for many applications because it is the most
abundant element on earth (although less than 1 % is present as molecular hydro-
gen), the gravimetric energy density is three times higher than liquid hydrocarbons
(142 MJ/kg versus 47 MJ/kg), and when burnt in oxygen the only exhaust is water.
One significant hurdle to the widespread adoption of hydrogen-burning vehicles,
however, is the development of new materials that can absorb and desorb large
amounts of hydrogen safely at low pressures and ambient temperatures. The
Department of Energy has set ambitious goals for the capacity, cycle life, and
delivery pressures required to make hydrogen a viable fuel for mobile applications
(Table 1 ). There are no current materials that can meet these goals to date.