Lithium-ion conduction in complex hydrides LiAlH4 and Li3AlH6

Lithium-ion conduction in complex hydrides LiAlH(4) and Li(3)AlH(6) was investigated using ac complex impedance measurements. The conductivities at room temperature were 8.7 x 10(-9) S/cm in the case of LiAlH(4) and 1.4 x 10(-7) S/cm in the case of Li(3)AlH(6). To enhance the conductivity of Li(3)AlH(6) having good thermal stability in heating/cooling cycles, mechanical milling, and addition of lithium halides (LiCl, LiI) were implemented. The maximum value of 2.5 x 10(-4) S/cm at 393 K was observed when 0.33 M ratio of LiI was added to Li(3)AlH(6). This study demonstrated two research directions to enhance the lithium-ion conductivity in a variety of complex hydrides. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3356981]