Direct preparation of LiBH₄ from pre-treated LiH + B mixture at high pressure

LiBH₄ was prepared from LiH + B mixture at 300-500 °C with a hydrogen pressure of 35 MPa. The LiH + B mixture was pretreated by ball milling under 10 MPa hydrogen pressure for 10 h. The results showed that ball-milling treatment is favorable for the formation of LiBH₄, which could reduce the reaction temperature for about 200 °C. A small quantity of LiBH ₄ could be found in the pre-treated sample. The formation of LiBH₄ from LiH + B mixture is a kinetically hindered progress and a diffusion-control reaction. LiBH₄ formed at 400 °C could release 6.59 wt.% H₂ when it was heated from room temperature to 500 °C. The yield of LiBH₄ is about 59.4%.