Dehydrogenation Performances of Different Al Source Composite Systems of 2LiBH₄ + M (M = Al, LiAlH₄, Li₃AlH₆)

Hydrogen has become a promising energy source due to its efficient and renewable properties. Although promising, hydrogen energy has not been in widespread use due to the lack of high-performance materials for hydrogen storage. Previous studies have shown that the addition of Al-based compounds to LiBH₄ can create composites that have good properties for hydrogen storage. In this work, the dehydrogenation performances of different composite systems of 2LiBH₄+ M (M = Al, LiAlH₄, Li₃AlH₆) were investigated. The results show that, under a ball to powder ratio of 25:1 and a rotation speed of 300 rpm, the optimum ball milling time is 50 h for synthesizing Li₃AlH₆ from LiH and LiAlH₄. The three studied systems destabilized LiBH₄ at relatively low temperatures, and the 2LiBH₄-Li₃AlH₆ composite demonstrated excellent behavior. Based on the differential scanning calorimetry results, pure LiBH₄ released hydrogen at 469°C. The dehydrogenation temperature of LiBH₄ is 416°C for 2LiBH₄-Li₃AlH₆ versus 435°C for 2LiBH₄-LiAlH₄ and 445°C for 2LiBH₄-Al. The 2LiBH₄-Li₃AlH₆, 2LiBH₄-LiAlH₄, and 2LiBH₄-Al samples released 9.1, 8, and 5.7 wt.% of H₂, respectively. Additionally, the 2LiBH₄-Li₃AlH₆ composite released the 9.1 wt.% H₂ within 150 min. An increase in the kinetics was achieved. From the results, it was concluded that 2LiBH₄-Li₃AlH₆ exhibits the best dehydrogenation performance. Therefore, the 2LiBH₄-Li₃AlH₆ composite is considered a promising hydrogen storage material.