Effects of Electrode Potential, SiCl4 Concentration, and Electrolysis Duration Period on Si Electrodeposition in a Hydrophobic Room-Temperature Molten Salt

Abstract

Effects of electrode potential and SiCl4 concentration on electrodeposition of Si were examined in trimethyl-n- hexylammonium bis(trifluoromethylsulfonyl)imide (TMHATFSI) containing various concentrations of SiCl4. A rougher and thicker film was electrodeposited in TMHATFSI containing higher concentration of SiCl4 or at more negative electrode potential. Current efficiency estimated from EDX spectra is highest at −2.0 V vs. Pt quasi-reference electrode (Q.R.E.). Time evolution of Si electrodeposition at −2.0 V vs. Pt Q.R.E. was also studied in TMHATFSI containing 0.1 M SiCl4. As the electrolysis progressed, the thickness of electrodeposited Si film increased, while current efficiency decreased, with approaching constant values.