Enhanced Hydrogen Generation by LiBH4 Hydrolysis in MOH/water Solutions (MOH: C2H5OH, C4H8O, C4H9OH, CH3COOH) for Micro Proton Exchange Membrane Fuel Cell Application

Abstract

LiBH4 has high hydrogen storage capacity, and its high gravimetric hydrogen density reaches 18.36%. However, LiBH4 exhibits poor hydrolysis performance in water because the abrupt ending caused by the agglomeration of its hydrolysis products limits its full utilization [1, 2]. In this paper, four kinds of organics, namely, ethanol, tetrahydrofuran, acetic acid, and butanol (referred to MOH) were added to water, and the effect of MOH species and amount on the hydrolysis performances of LiBH4 was evaluated. Results show that agglomeration can be avoided and that LiBH4 has a controllable hydrogen generation rate and high hydrogen generation amount inMOH/water solutions compared with that in pure water. The order in terms of the hydrolysis performance of LiBH4 in MOH/water solutions is as follows: acetic acid >butanol> tetrahydrofuran >ethanol. From XRD, SEM, and other analyses, the enhancement performance is explained by the diluting and solvent effects. Moreover, the addition of MOH alters the hydrolysis route of LiBH4. MOH acts as not only a carrier for water and LiBH4 but also as a reactant to form intermediate LiBH4·[MOH(H2O)x]y, which slows the hydrolysis kinetics of LiBH4. Hydrolysis conditions were optimized, and high hydrogen amount was achieved correspondingly. The experimental data presents the potential application of LiBH4 as a highly efficiency and stable hydrogen source for fuel cells.