High-yield fabrication of graphene-wrapped silicon nanoparticles for self-support and binder-free anodes of lithium-ion batteries

Composites of graphene-wrapped Si nanoparticles (NPs) have been assembled via a one-pot liquid nitrogen fast freezing followed by a thermal reduction. It is found that, as a self-support and binder-free anode of lithium-ion battery, the composited graphene is helpful to form a uniform morphology, reduce the resistance of the electrode and isolate the Si NPs from the electrolyte to suppress the formation of unstable solid electrolyte interphase. Moreover, it can buffer the strain from the volume change of the Si NPs. The composite with an optimized mass ratio of reduced graphene oxide (rGO) to Si NPs exhibits significantly improved lithium storage performance with an excellent rate capability and a large reversible capacity of 1482 mAh g−1 at a current density of 210 mA g−1 after 300 cycles. Furthermore, the electrochemical reaction kinetics and interfacial behavior of the rGO/Si composites are investigated in-depthly. The work reported here can be extended to the fabrication of the other graphene-based materials.