Method for preparing lithium borohydride by means of solid-phase ball milling at room temperature

A method for preparing lithium borohydride by means of solid-phase ball milling at room temperature, comprising the following steps:

• under room temperature and non-oxidizing atmosphere, solid-phase ball milling, separating, and purifying uniformly mixed magnesium-containing reducing agent and a lithium metaborate-based material to obtain the lithium borohydride (LiBH4);
• wherein the magnesium-containing reducing agent is one or more selected from the group consisting of magnesium, aluminum magnesium and calcium magnesium alloys;
• the lithium metaborate-based material is composed of both hydrous lithium metaborate and anhydrous lithium metaborate, or the lithium metaborate-based material is hydrous lithium metaborate;
• and
• the non-oxidizing atmosphere is an argon atmosphere or a mixed atmosphere of argon and hydrogen;
• the non-oxidizing atmosphere holds a pressure of 0-3 MPa.