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 TiO2 in exfoliating graphite to be graphene layers effectively is reported. As a paradigm, this discovered effect of TiO2 is significant for preparing high-performance graphene-modified SiOx-based anode in lithium-ion batteries (LIBs), in which the graphite is in situ exfoliated mechanically by TiO2 to be multilayered graphene (i.e., MLG) and then the SiOx is wrapped by the MLG to construct a SiOx/TiO2@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 SiOx effectively. This result is hard to be achieved using other kinds of metal oxide besides TiO2. It is hoped that the SiOx/TiO2@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.