THE EFFECTS OF HYDROSTATIC PRESSURE ON MBH4 (M = K, Na) STRUCTURES

Abstract

In recent decades, a lot of efforts has been spent on investigation of metal borohydrides, which can potentially serve as advanced hydrogen storage materials for mobile applications. In this research, we investigate the structure changes under high pressure of the compounds MBH 4 (M = K, Na) as important borohydrides in hydrogen technologies, using ABINIT simulation package based on density functional theory (DFT) and the generalized gradient approximation (GGA). The pressure is in a wide range of 0 GPa to 40 GPa. Structural analysis indicates the phase transformation in the examined range of pressure, which is evidenced by the interaction between metal cations and BH 4 -, interactive behavior of BH 4 tetrahedron in the simulated cells, change of volume, distance between B and H ions, and enthalpy difference.