Unraveling Metal Oxide Role in Exfoliating Graphite: New Strategy to Construct High-Performance Graphene-Modified SiOx-Based Anode for Lithium-Ion Batteries

Exfoliating graphite to graphene has attracted great attention due to the fantastic properties of graphene available for designing graphene-based materials or devices. Besides the classic solution method, herein a unique role of TiO 2 in exfoliating graphite to be graphene layers effectively is reported. As a paradigm, this discovered effect of TiO 2 is significant for preparing high-performance graphene-modified SiO x -based anode in lithium-ion batteries (LIBs), in which the graphite is in situ exfoliated mechanically by TiO 2 to be multilayered graphene (i.e., MLG) and then the SiO x is wrapped by the MLG to construct a SiO x /TiO 2 @MLG. In this case, an extremely high capacity of 1484 mAh g −1 , long lifespan over 1200 cycles at 2 A g −1 , as well as good performance in full LIBs (vs nickel-rich cathode) are demonstrated. It is confirmed that the MLG can enhance electric conductivity, mitigate electrolyte decomposition, and alleviate volume effect of the SiO x effectively. This result is hard to be achieved using other kinds of metal oxide besides TiO 2 . It is hoped that the SiO x /TiO 2 @MLG is practical for pursuing LIBs with an energy density beyond 300 Wh kg −1 . In addition, it is believed the ingenious strategy is applicable for designing more functional materials with greater capabilities.