Improvement of Cycling Performance of Silicon-Graphite Composite Anode Using Blended Electrolyte Additives

Abstract

Silicon-graphite composite anode materials are potential alternatives to graphite anode material for high-energy density Li-ion batteries, as the theoretical specific capacity of silicon is ten-fold larger than that of commercialized graphite.1,2 However, the major drawback of silicon-based anode material is a short cycle life caused by large volume change, low electrical conductivity and mechanical disintegration of particles. To overcome those issues, a variety of methods for improving cycle performance of silicon-based anodes have been researched, such as the use of composite with larger fraction of graphite,3,4 modification of surface property of silicon,4 and the use of new binder, nanostructured silicon, and functional electrolyte additives.3 Recently, the batteries with composite material containing very low fraction of silicon are being commercialized, which can accommodate the large volume change of silicon and obtain reasonable electrical conductivity. Another promising approach is the control of electrode-electrolyte interfacial reaction for the formation of a stable solid electrolyte interphase (SEI) utilizing functional electrolyte additives, which has to be based on a basic understanding of interfacial phenomena. In this presentation, we report the improved cycle performance and the interfacial phenomena of silicon-graphite composite anodes under the condition of various blended additives. Acknowledgements This research was supported by the Korean Ministry of Trade, Industry & Energy (10049609), National Research Foundation (2012026203), and Nano-Material Technology Development Program by the Ministry of Science, ICT and Future Planning (2009-0082580).