Electrochemical lithiation of thin silicon based layers potentiostatically deposited from ionic liquid. (20th June 2015)

• Record Type: Journal Article
• Authors: Vlaic, Codruta Aurelia; Ivanov, Svetlozar; Peipmann, Ralf; Eisenhardt, Anja; Himmerlich, Marcel; Krischok, Stefan; Bund, Andreas
• Is Part Of: Electrochimica acta. Volume 168(2015)
• Page Start: 403
• Page End: 413
• Publication Date: 2015-06-20
• Subjects: silicon electrodeposition -- ionic liquid -- Li ion battery -- quartz crystal microbalance -- X-ray photoelectron spectroscopy; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2015.03.216
• Languages: English
• ISSNs: 0013-4686

Abstract

Abstract: Thin silicon layers containing about 20% carbon and 20% oxygen were deposited on copper substrates by potentiostatic electroreduction from a 1 M SiCl4 1-butyl-1-methyl-pyrrolidinium bis (trifluoromethyl) sulfonylimide [BMP][TFSI] electrolyte. The electrodeposition process was investigated by means of voltammetric techniques, coupled with in-situ microgravimetry (quartz crystal microbalance, QCM). The electrochemical and QCM data suggest a possible contribution of a partial Si 4+ to Si 2+ reduction and/or a restructuring of the metallic substrate. Considerable impact of side reactions parallel to the deposition process was indicated by QCM measurements performed under potentiostatic and potentiodynamic conditions. The deposition of silicon-based films was confirmed by energy dispersive X-ray analysis (EDX). Analysis of the chemical composition of the deposit and its elemental distribution were achieved by depth profiling X-ray photoelectron spectroscopy (XPS). The electrodeposited silicon containing layers showed stable lithiation and delithiation with capacity values of about 1200 mAhg −1 and 80% capacity retention after 300 cycles in standard EC/DMC electrolytes. In ionic liquid (IL) the material displayed lower capacity of ca. 500 mAhg −1, which can be attributed to the higher viscosity of this electrolyte and deposition of IL decomposition products during lithiation.