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Keywords:

  • anodes;
  • batteries;
  • graphene;
  • lithium;
  • silicon

Abstract

A chemical vapor deposition process is introduced to prepare silicon (Si)–graphene composite anode materials for lithium-ion batteries. Highly ordered crystalline Si particles are deposited onto graphene sheets by using a liquid chlorosilane as Si source. The Si–graphene composite exhibits high utilization of Si in charge–discharge processes. The capacity retention of 90 % after 500 full cycles and an average Coulombic efficiency in excess of 99.5 % are achieved in half cells. Moreover, atomic layer deposition (ALD) Al2O3 coating is directly applied on the Si-graphene electrode, which greatly suppresses the side reactions between the electrode and electrolyte, resulting in the enhancement in initial Coulombic efficiency and reversible capacity. Finally, a 3.6 V full cell device is demonstrated, which works very well by combining a Si-graphene anode with a Li-excess layer-structured composite Li1.2Ni0.2Mn0.6O2 cathode. This approach is very promising for realizing a high-energy lithium-ion battery.