Exfoliated graphite as a flexible and conductive support for Si-based Li-ion battery anodes

Exfoliated graphite (EG) was found to be a flexible and conductive support of anode materials for lithium ion batteries through the preparation of the composite of pyrolytic carbon-coated nano-sized silicon nanoparticles supported by exfoliated graphite (pC-Si-EG). Electrochemical analyses revealed that pC-Si-EG composite delivered a high capacity of 902.8 mAh g−1 at a current density of 200 mA g−1 and an excellent cycling stability with 98.4% capacity retention after 40 cycles. It was found that the polycrystalline silicon nanoparticles went through some very interesting changes and broke up into smaller Si nanoparticles dispersing onto the surface of EG after charging/discharging cycles. The results demonstrated that EG plays an important role in the superior electrochemical performances of pC-Si-EG anode due to its high porosity, excellent electronic conductivity and good flexibility.