Ammine bimetallic (Na, Zn) borohydride for advanced chemical hydrogen storage

The synthesis and dehydrogenation performance of purified NaZn(BH4)(3) with a new phase and its novel ammine metal borohydride, NaZn(BH4)(3)center dot 2NH(3), were first reported. Structure analysis shows that NaZn(BH4)(3)center dot 2NH(3) crystallizes in an orthorhombic structure with lattice parameters of a = 7.2965(2) angstrom, b = 10.1444(2) angstrom and c = 12.9714(3) angstrom and space group P2(1)nb, in which the Zn atoms are located in a tetrahedral coordination environment with two NH3 molecules and two BH4- units, presenting a novel 3D framework comprised of isolated BH4-1 units and [NaZn(BH4)(2)(NH3)(2)](+) complexes. Dehydrogenation results showed that the ZnCl2 assisted NaZn(BH4)(3)center dot 2NH(3) is able to release 7.9 wt% hydrogen at 110 degrees C without the concomitant release of undesirable gases such as ammonia and/or boranes, thereby demonstrating the potential of the ammoniated Zn-based borohydrides to be used as solid hydrogen storage materials.