Simultaneously bead-milled and reduced submicron silicon and graphene oxide for lithium storage

To utilize efficiently micron-scaled silicon (μSi) for Li-storage, it is crucial to solve two awkward issues, electrode pulverization and low conductivity. A scalable high energy bead milling (BM) approach adopted in this work can minimize simultaneously Si granules and graphene oxide (GO) thickness. Meanwhile, milling energy can intensify Si/GO interaction. After a co-reduction process at 800 °C in Ar gas atmosphere, r(BM-μSi/GO) powder, featured with submicron Si particles enveloped by reduced GO (rGO), can be prepared. Although bead milling may induce surface defects like oxidation and atom disordered array, crystalline structure can be restored via thermoreduction. Carbon encapsulation improves Li+ transport efficiency and electron transport rate by reducing the volume expansion and direct exposure of Si particles, thus promoting the formation of stable solid electrolyte interface (SEI) films and reducing the irreversible Li+ consumption. With specific capacity of, 842.5 mA h g−1 at 1.0 A g−1 and 364.9 mA h g−1 at 5 A g−1 after 800 cycles, r(BM-μSi/GO) exhibits upgraded capacity and long cycling stability. Owing to the stress-relief of void-rich structure and rGO confinement, structural integrity of Si anode can be guaranteed, which benefit to sustain the capacity and durability, even at high current densities.