The invention discloses high-purity
lithium borohydride and a preparation method thereof, and belongs to the technical field of inorganic synthesis.The preparation method comprises the steps that firstly, surface coordination activation is conducted on micron-sized
lithium hydride through amino
silane, and the reaction activity of the micron-sized
lithium hydride is remarkably improved; and then, in a uniform
ionic liquid organic solvent composite medium, efficiently synthesizing
lithium borohydride with a purified
borane complex at a mild temperature. For key
impurity chloride ions, trimethylchlorosilane is innovatively introduced to carry out targeted
precipitation conversion, and effective removal is carried out before
crystallization. And finally, directly separating out a high-purity product from a
reaction system through a directional
crystallization technology. According to the high-purity
lithium borohydride and the preparation method thereof disclosed by the invention, high-efficiency preparation of high-purity and low-
chloride-
ion lithium borohydride under a mild condition is realized, a key
reagent can be recycled, and the problems of
high energy consumption and insufficient purity in a traditional method are perfectly solved.