Electrochemical properties of carbon-coated Si/B composite anode for lithium ion batteries

Carbon-coated Si and Si/B composite powders prepared by hydrocarbon gas (argon + 10 mol% propylene) pyrolysis were investigated as the anodes for lithium-ion batteries. Carbon-coated silicon anode demonstrated the first discharge and charge capacity as 1568 mAh g(-1) and 1242 mAh g(-1), respectively, with good capacity retention for 10 cycles. The capacity fading rate of carbon-coated Si/B composite anode decreased as the amounts of boron increased. In addition, the cycle life of carbon-coated Si/B/graphite composite anode has been significantly improved by using sodium carboxymethyl cellulose (NaCMC) and styrene butadiene rubber (SBR)/NaCMC mixture binders compared to the poly(vinylidene fluoride. PVdF) binder. A reversible capacity of about 550 mAh g(-1) has been achieved at 0.05 mAm g(-1) rate and its capacity could be maintained up to 450 mAh g(-1) at high rate of 0.2 mAm g(-1) even after 30 cycles. The improvement of the cycling performance is attributed to the lower interfacial resistance due to good electric contact between silicon particles and copper substrate. (C) 2008 Published by Elsevier B.V.