Silicon Few-Layer Graphene Nanocomposite as High-Capacity and High-Rate Anode in Lithium-Ion Batteries

Abstract

A silicon-graphene heterostructure provides optimal electrochemical performance as anode nanomaterial in both half and full cells with a commercial NMC111 (LiNi1/3Mn1/3Co1/3O2) cathode. The anode consists of carbon-coated polycrystalline silicon nanoparticles in between a parallel oriented few-layers graphene flakes (FLG). Electrochemical tests in lithium cells display high capacity values (∼2300 mAh/g) with a Coulombic efficiency (CE) reaching 99% at current density of 350 mA/g and 1000 mAh/g at current density values up to 3.5 A/g (CE = 99%). The laminated graphene-based structure yields a protective coating to the silicon nanoparticles still enabling exposure to lithium ions. The method of production of the laminated silicon-graphene nanocomposite is scalable and low-cost, offering a practical route to the introduction of high silicon content anodes in lithium-ion batteries.