Preparation and characterization of flake graphite/silicon/carbon spherical composite as anode materials for lithium-ion batteries

Using nano-Si, glucose and flake graphite of ∼0.5 μm as raw materials, flake graphite/silicon/carbon composite is successfully synthesized via spray drying and subsequent pyrolysis. The samples are characterized by XRD, SEM, TEM and electrochemical measurements. The composite is composed of flake graphite, nano-Si and amorphous glucose-pyrolyzed carbon and presents good spherical appearance. Some micron pores arising from the decomposition of glucose exist on the surface of the composite particles. The composite has a high reversible capacity of 602.7 mAh/g with an initial coulombic efficiency of 69.71%, and shows nearly the same cycleability as the commercial graphite in 20 cycles. Both the glucose-pyrolyzed carbon and the micron pores play important roles in improving the cycleability of the composite. The flake graphite/silicon/carbon composite electrode is a potential alternative to graphite for high energy-density lithium ion batteries.

► Flake graphite/silicon/carbon composite is synthesized via spray drying.
► Flake graphite of ∼0.5 μm and glucose are used to prepare the composite.
► The as-prepared composite shows spherical and porous appearance.
► The composite shows nearly the same cycleability as commercial graphite in 20 cycles.
► The composite shows a reversible capacity of 552 mAh/g at the 20th cycle.