Si-O-C materials prepared with a sol-gel method for negative electrode of lithium battery

A sol-gel method is employed to prepare high capacity Si-O-C materials. A blend of polysiloxane and divinylbenzene is uniformly spread in the ethanol solution of triethoxysilane and diethoxymethylsilane, which is then hydrolyzed, crosslinked and finally pyrolyzed at 1000 degrees C in a hydrogen atmosphere to obtain the final composite materials. The resultant materials, as indicated by elemental analysis, mainly consist of Si-O-C glass phase, in which the dominant silicon species is identified to SiO4 units by Si-29 magic angle spinning nuclear magnetic resonance and Si (2p) X-ray photoelectron spectroscopy. The Si-O-C materials exhibit a stable reversible capacity of ca. 900 mAh g(-1), originating from lithium storage in SiO4 units, with a coulombic efficiency of 98.5%. (C) 2012 Elsevier B.V. All rights reserved.