Three-dimensional CNTs boosting the conductive confinement structure of silicon/carbon anodes in lithium-ion batteries

Abstract

In this study, a surface functionalization strategy was proposed to involve carbon nanotubes and silicon nanoparticles encapsulated within carbon derived from a zeolite imidazole framework (ZIF-67). Multidimensional interconnected carbon nanotubes bolster the structural stability and facilitate ion/electron transfer within silicon/carbon composites. Silicon nanoparticles were successfully encapsulated in ZIF-67-derived carbon shells, with carbon nanotubes effectively transferring interfacial stress between silicon and carbon shell during lithiation, where ZIF-67-derived carbon reduces the volume expansion in silicon anodes. As a consequence, the outstanding cycle life and rate performance were demonstrated in the silicon/carbon composites. The specific capacity was maintained at 660 mAh g-1 over 200 cycles at 1 A g-1. The in-situ construction of this conductive confinement structure based on three-dimensional carbon nanotubes offers a promising design approach for advancing silicon/carbon anode technologies.