A new design for Si wears double jackets used as a high-performance lithium-ion battery anode

Abstract

Since most active nanoparticles (Si, Sn, TiO2, SnO2, etc.) are simply decorated on the graphene surface instead of being contained between the graphene nanoarray, they are easily peeled off during the long-term cycling. A new Si-based double jackets nanostructure synthesized by synergistic coupling of TiO2@RGO coating layer, supporting large current density for charge/discharge, is reported as an anode material for lithium-ion batteries. The new heterostructure modifies the surface of Si and TiO2 to ensure a firm bond between the interfaces, layer by layer self-assembly dispersed in the reduced graphene oxide (Si@TiO2@RGO). Compared with the regular Si@G composites, Si@TiO2@RGO exhibits excellent electrochemical performance, mainly due to the strong interfacial binding force among the three, thus the integrity of the electrode structure is ensured in the lithiation/delithiation process. As a consequence, the Si@TiO2@RGO electrode exhibits a stable reversible specific capacity of 1679.1 mAh g−1 at a large current density of 1.4 A g−1 after 900 cycles.