Role of Early-Stage Atmosphere in the Dehydrogenation Reaction of the LiBH4-YH3 Composite

Abstract

This article investigates the dehydrogenation behavior of the LiBH4-YH3 composite under various early-stage Ar back-pressure conditions. It is clearly observed that a minute change in early-stage atmosphere greatly affects the overall dehydrogenation reaction of the composite. Free boron and Li2B12H12 start to form in turn as the partial dehydrogenation products around 400 C under static vacuum or low Ar back pressure. The formation of Li2B12H12 greatly increases the activation energy for the dehydrogenation reaction between LiBH4 and YH3 into LiH and YB4, hence significantly retarding the reaction. The formation of B just slightly increases the incubation period of the reaction. The formation of Li2B12H12 is effectively suppressed by initially applying Ar back pressure above 0.1 MPa.