Synthesis of Monosilane by Molten Salt Electrochemical Process

摘要

With the aim of developing a novel SiH_4 production method, electrode behavior of a metal grade Si and formations of SiF_4 and SiH_4 were investigated in molten LiCl-KCl-LiF and LiCl-KCl-LiF-LiH systems at 673 K. In a molten LiCl-KCl-LiF(5 mol%) system, continuous electrolysis to form SiF_4 was possible at 2.8 V (vs. Li~+/Li). In a molten LiCl-KCl-LiF(5 mol%)-LiH(0.8 mol%) system, formation of SiH_4 was confirmed at more positive potential than 2.1 V (vs. Li~+/Li) and current efficiency for SiH_4 formation was estimated to be approximately 20 % at 2.8 V. Transformation of SiF_4 into SiH_4 was confirmed by bubbling SiF_4 into the melt. Continuous electrolysis to form SiH_4 was difficult because of the passivation of the electrode.