Kinetic- and thermodynamic-based improvements of lithium borohydride incorporated into activated carbon

LiBH4 was incorporated into an activated carbon (AC) scaffold using a chemical impregnation method. Confinement of LiBH4 within the carbon nanopores was found to significantly improve both the hydrogen sorption kinetics and thermodynamics, compared to the bulk hydride. The LiBH4/AC sample starts to release hydrogen from just 220 °C, which is 150 °C lower than the onset dehydrogenation temperature of bulk LiBH4. The dehydrogenation rate of the LiBH4/AC sample was one order of magnitude faster than that of bulk LiBH4. The temperature and hydrogen pressure conditions required for restoring the hydride were also significantly reduced when LiBH4 was incorporated into AC. Preliminary study showed that the dissociation hydrogen pressure of LiBH4 could be enhanced by around one order of magnitude upon incorporating the hydride into AC. X-ray diffraction, Fourier transform infrared spectroscopy and nitrogen adsorption analyses were used to confirm the nanostructure of LiBH4 in the AC scaffold.