Process method for preparing ammonia borane from boroxol acid ammonium through electrochemical reduction in recycling manner

The invention discloses a process method for preparing ammonia borane from boroxol acid ammonium through electrochemical reduction in a recycling manner. According to the process method, electrochemical reduction is carried out by virtue of a three-dimensional negative electrode with relatively high hydrogen overpotential under an electrochemical reduction principle based on ammonia borane hydrolysate ammonia metaborate as a raw material, so that conversion of boroxol acid radical ions into borone hydrogen acid radical ions is promoted. White floppy ammonia borane solid can be prepared through operation steps such as boroxol acid ammonium electroreduction, freeze-drying dehydration, dissolution backflowing, centrifugal treatment, rotation evaporation, crystallization and the like. The process method is gentle in preparation condition, short in process, low in energy consumption, simple and convenient to operate, free of waste discharge and free of environment pollution, and the raw materials which are byproducts generated from hydrolysis hydrogen release of ammonia borane are low in price and easily available. In addition, due to adoption of an appropriate electrode material, the current efficiency of electroreduction of a negative electrode chamber to generate hydroboron can be improved.