3D-structured multi-walled carbon nanotubes/copper nanowires composite as a porous current collector for the enhanced silicon-based anode

Abstract In this study, multi-walled carbon nanotubes/Cu nanowires-coated on the copper foil used as a three-dimensional porous current collector for Si electrode has been developed to tackle the problems of silicon-based lithium-ion batteries. The highly conductive Cu nanowires cooperated with robust multi-walled carbon nanotubes not only improve the inferior electric conductivity of the Si anode but also strengthen the total frame stability. Furthermore, the three-dimensional structure creates numerous voids on the surface of Cu foils. Such porous structure of the modified current collector offers the flexible volume expansion during lithiation/delithiation process. Meanwhile, the core-shell structure of multi-walled carbon nanotubes/Si and Cu nanowires/Si minimizes the deformation strain and greatly improves the long-term cycling performance in a real battery. As a result, a high specific capacity of 1845 mAh g−1 in a half cell at a current density of 3.5 A g−1 after 180 cycles with a capacity retention of 85.1% has been achieved without any conductive additives or binder. The demonstrated three-dimensional current collector coupled with Si anode might inspire new material development on high-performance of lithium-ion batteries.