Computational Screening of Dual-Cation Metal Ammine Borohydrides by Density Functional Theory

A computational screening study consisting of crystal structure prediction and density functional theory has been performed for dual-cation ammine metal borohydrides (AMBs) with a general formula of M1M2(BH4)(3)(NH3)(2-6) (M-1 = Li, Na, or K and M-2 = Sr, Ca, Mg, Zn, Mn, or Ni). The stability and decomposition energies of the resulting 90 alloys were used for the evaluation of the screening. It has been observed that two recently synthesized dual-cation AMBs (LiMg(BH4)(3)(NH3)(2) and NaZn(BH4)(3)(NH3)(2)) are predicted to form stable alloys. Moreover, the M-1 (Mn,Mg) (BH4)(3)(NH3)(2-6) and M1Ni(BH4)(3)-(NH3)(4-6) alloys, which are not synthesized yet, are also found to be promising.