Enhanced cycle life of Si anode for Li-ion batteries by using modified elastomeric binder

Cycle-life of the particulate electrode of Si, either with or without carbon coating, for Li-ion battery has significantly been improved by using a modified elastomeric binder containing styrene-butadiene-rubber (SBR) and sodium-carboxyl-methylcellulose (SCMC). Compared with poly-vinylidene-fluoride (PVdF), the (SBR + SCMC) mixture binder shows smaller moduli, a larger maximum elongation, a stronger adhesion strength on Cu current collector, and much smaller solvent-absorption in organic carbonate. There were demonstrated cycle lives of >50 cycles for bare Si at 600 mAh/g or carbon-coated Si at 1000 mAh/g, as contrast to less than or equal to8 cycles for PVdF-bound electrode in all cases. (C) 2004 The Electrochemical Society.