Graphene caging core-shell Si@Cu nanoparticles anchored on graphene sheets for lithium-ion battery anode with enhanced reversible capacity and cyclic performance

With the large-scale practical application of electric vehicles and mobile devices, more and more attention has been focused on the research of high specific capacity lithium-ion batteries (LiBs) anode materials. Novel graphene caging core-shell Si@Cu nanoparticles anchored on graphene sheets (Si@Cu@rGO) anode was prepared by deposition-precipitation and one-step thermal reduction methods. During the preparation, CuC2O4 and graphene oxide are simultaneously reduced and coated on silicon nanoparticles. Introduced copper can enhance charge transfer kinetics of the electrode and suppress the tight cluster of Si nanoparticles. Besides, the graphene nanocage outside Si@Cu nanoparticle restricts polarization and pulverization of silicon inside itself. Graphene provides not only buffering space for core-shell Si@Cu nanoparticles to expand but also a conductive network to enhance the electronic conductivity and flexibility of the electrode. Therefore, the synergism of copper shells and graphene sheets improved electrochemical performance. The Si@Cu@rGO composites exhibited the reversible capacity of 2095.2 mAh g(-1) at 200 mA g(-1) after 50 cycles, showing extraordinary electrochemical performance. This outstanding Si@Cu@rGO anode becomes an ideal candidate for superior silicon-based lithium-ion battery applications. (C) 2020 Elsevier Ltd. All rights reserved.