A comparison of conventional heating techniques and microwave irradiation for the desorption of lithium borohydride and lithium borohydride composites

摘要

The desorption of lithium borohydride and lithium borohyride composites was examined using both conventional heating techniques and microwave irradiation. LiBH4 was milled with TiH2 in various molar ratios in an argon atmosphere using both roller and planetary mill techniques. Thermo-gravimetric analysis and differential scanning calorimetry determined the desorption characteristics of the as received and milled materials. Scanning electron microscopy was used to examine the particle size of the materials before heating. A temperature programmed desorption (TPD) rig and a custom built microwave rig were both connected to the same gas aborption system which was pressurised with hydrogen and could be operated with each system independently. A comparison in desorption characteristics was made between conventional TPD heating techniques and microwave irradiation for the as received and milled materials; mass flow controllers were able to measure the amount of hydrogen desorbed in both cases. X-ray diffraction was conducted on the samples before and after heating in the TPD rig. TiH2 was found to kinetically destabilise the desorption of LiBH4 in all techniques. Microwave induced desorption produced faster heating rates than were exhibited with conventional heating techniques using less energy, with similar amounts of hydrogen gas being desorbed in a much shorter time period.