In-situ FTIR investigations on the reduction of vinylene electrolyte additives suitable for use in lithium-ion batteries

Abstract

Lithium-ion batteries operate beyond the thermodynamic stability of the aprotic organic electrolyte used and electrolyte decomposition occurs at both electrodes. The electrolyte must therefore be composed in a way that its decomposition products form a film on the electrodes which stops the decomposition reactions but is still permeable to the Li(+) cations which are the charge carriers. At the graphite anode, this film is commonly referred to as a solid electrolyte interphase (SEI). Aprotic organic compounds containing vinylene groups can form an effective SEI on a graphitic anode. As examples, vinyl acetate (VA) and acrylonitrile (AN) have been investigated by in-situ Fourier transform infrared (FTIR) spectroscopy in a specially developed IR cell. The measurements focus on electrolyte decomposition and the mechanism of SEI formation in the presence of VA and AN. We conclude that cathodic reduction of the vinylene groups (i.e., via reduction of the double bond) in the electrolyte additives is the initiating and thus a most important step of the SEI-formation process, even in an electrolyte which contains only a few percent (i.e. electrolyte additive amounts) of the compound. The possibility of electropolymerization of the vinylene monomers in the battery electrolytes used is critically discussed on the basis of the IR data obtained.

In situ microscope FTIR spectroscopic studies of interfacial reactions of Sn–Co alloy film anode of lithium ion battery

“…The chemical compositions of SEI layers on various materials of LIBs, aged or cycled in different electrolytes, were examined by ex situ FTIRS [9][10][11][12][13]. In situ FTIRS investigations focusing on the reduction/oxidation of various electrolytes were carried on LIBs electrodes [14][15][16][17][18] or nonactive [19,20] materials. On the traditional LIBs powder electrode materials, however, the strong absorption of IR light makes it difficult to be studied by FTIRS due to a low reflectivity for incident IR radiation in most cases.…”

Electrochemical Performance and Thermal Stability Studies of Two Lithium Sulfonyl Methide Salts in Lithium-Ion Battery Electrolytes

“…11,[19][20][21][22][23][24][25] However, with increasing demands on the electrolyte regarding thermal and/or electrochemical stability, the limitations of such electrolyte mixtures are unraveled. 11,26,27 Alternative electrolyte compositions that depict certain improvements compared to the state-of-the-art electrolyte are still required to fulfil the following properties: a sufficient ionic conductivity to transport the lithium ions, the ability to form an effective solid electrolyte interphase (SEI) on the graphitic anode [28][29][30][31][32][33][34][35][36][37] which enables stable cycling in the low potential range as well as inertness toward aluminum to avoid anodic dissolution of the current collector on the cathode side. 38,39 In addition to performance, more general aspects like low price and environmental compatibility are important as well.…”

Control of Surface Chemistry and Electrochemical Performance of Carbon-coated Silicon Anode Using Silane-based Self-Assembly for Rechargeable Lithium Batteries

“…The -(CH=CH 2 ) vinyl functionality of tris(2-methoxyethoxy)vinylsilane is known to undergo cathodic electro-polymerization around 0.8 V at the surface of electrode. 38,39 The polymerization process could increase additionally the cathodic capacity, despite its low concentration level 5 wt %. Large capacities of 1480 -2130 mAh/g and preserved capacity retention of 74% over 200 cycles in Fig.…”