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 °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 29Si 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%. ► A sol–gel method is used to prepare Si–O–C anode materials. ► The formed materials exhibit a high capacity and good cyclic performance. ► The high capacity comes from lithium storage in SiO4 units.