High Pressure Behavior of Hydrogen Storage Material Guanidinium Borohydride

A combination of synchrotron powder angle-dispersive X-ray diffraction (ADXRD) and Raman spectroscopy has been utilized to study high pressure behavior of the chemical hydrogen storage material guanidinium borohydride (GBH) [C(NH2)(3)] [BH4](-). A reversible structural phase transition was observed at approximately 0.4 GPa, evidenced by the obvious changes in ADXRD patterns and Raman spectra. Both Raman spectra and the first-principles calculation revealed that new dihydrogen bonds generated under high pressure, which was proposed to be the reason for the observed phase transition. This research explored the pressure induced changes of GBH and studied the evolution of dihydrogen bonds, which can give insight into the improvement of the hydrogen release properties.