Exceptional Effect of Benzene in Uniform Carbon Coating of SiO x Nanocomposite for High-Performance Li-Ion Batteries

Abstract

© 2018 The Electrochemical Society. A novel SiO x @C composite is designed that uses benzene for both the homogenous dispersion of the Si source and simultaneous fabrication of a multiple carbon matrix on the composite. The overall morphology of the SiO x @C composite and uniformly carbon-coated Si nanoparticles are verified using transmission electron microscopies with elemental mapping. This benzene-based synthesis process results in exceptional electrochemical properties for SiO x . At a current density of 0.5 A g −1 , the SiO x @C composite delivers a discharge capacity of 591 mAh g −1 with 99% coulombic efficiency over 600 cycles. Furthermore, the SiO x @C composite exhibits outstanding power capability with a capacity of 602 mAh g −1 at a current density of 2 A g −1 , corresponding to ∼68% of that measured at 0.1 A g −1 . In contrast, the capacity of pristine SiO x is extremely degraded under similar conditions.