Effect of carbon addition on hydrogen storage behaviors of Li-Mg-B-H system

Various carbon additives were mechanically milled with LiBH4/MgH2 composite and their hydrogen storage behaviors were investigated. It was found that most of the carbon additives exhibited prominent effect on the host material. Among the various carbon additives, purified single-walled carbon nanotubes (SWNTs) exhibited the most prominent effect on the kinetic improvement and cyclic stability of Li-Mg-B-H system. Results show that LiBH4/MgH2 composite milled with 10 wt.% purified SWNTs additive can release nearly 10 wt.% hydrogen within 20 min at 450 °C, which is about two times faster than that of the neat LiBH4/MgH2 sample. On the basis of hydrogen storage behavior and structure/phase investigations, the possible mechanism involved in the property improvement upon carbon additives was discussed.