A Potential Method of Hydrogen Generation from Milled Al-LiH Mixture in Water

Abstract

Hydrogen generation by hydrolysis of Al-LiH mixture was investigated in pure water. The results showed that the hydrolysis rate of Al-LiH mixture obtained by high-energy ball milling was significantly improved, comparing to lower reactivity of milled pure aluminum in water. The 20 h-milled Al-LiH (³ 15 wt %) mixture displayed a high conversion yield of 87-100 %, comparing with unhydrolyzed milled Al at 25 ºC. Its high reactivity was attributed to the hydrolysis of LiH and numerous defects and fresh surfaces after milled, which was helpful to accelerate the hydrolysis of aluminum in water. In addition, the presence of tin could improve hydrolysis kinetic of Al-LiH mixture. A maximum yield of 93 %, that was, a hydrogen gravimetric yield of 10 % (including tin mass and excluding water mass) had been obtained. The positive effect of tin addition on yield and kinetics of the mixture was explained from the creation micro-galvanic cells between Al and Sn components, which was simulated by hydrolysis byproduct of LiH.