A 3D porous architecture of Si/graphene nanocomposite as high-performance anode materials for Li-ion batteries

Abstract

A 3D porous architecture of Si/graphene nanocomposite has been rationally designed and constructed through a series of controlled chemical processes. In contrast to random mixture of Si nanoparticles and graphene nanosheets, the porous nanoarchitectured composite has superior electrochemical stability because the Si nanoparticles are firmly riveted on the graphene nanosheets through a thin SiO_x layer. The 3D graphene network enhances electrical conductivity, and improves rate performance, demonstrating a superior rate capability over the 2D nanostructure. This 3D porous architecture can deliver a reversible capacity of ∼900 mA h g⁻¹ with very little fading when the charge rates change from 100 mA g⁻¹ to 1 A g⁻¹. Furthermore, the 3D nanoarchitechture of Si/graphene can be cycled at extremely high Li⁺ extraction rates, such as 5 A g⁻¹ and 10 A g⁻¹, for over than 100 times. Both the highly conductive graphene network and porous architecture are considered to contribute to the remarkable rate capability and cycling stability, thereby pointing to a new synthesis route to improving the electrochemical performances of the Si-based anode materials for advanced Li-ion batteries.