Building Three-Dimensional Network Structures of Silicon–Graphite/Carbon Nanotube Composite Anode for High-Energy Lithium-Ion Batteries

Abstract

As the increasing demand for high-energy-density lithium-ion batteries (LIBs), silicon-based anodes have become an excellent alternative to conventional graphite anodes owing to their high theoretical capacities. In this study, a three-dimensional (3D) electric network structure was developed using an aqueous carbon nanotube (CNT) suspension to improve the specific capacity and cyclability of Si–graphite electrodes. Field-emission scanning electron microscopy demonstrated that longer single-walled CNTs (SWCNTs) effectively covered and interconnected the entire surface of the Si and graphite particles, thereby providing electric conduction networks and facile access to Li ions in the electrode and structural strength with flexibility. As a result, 3D networks structure of Si–graphite/SWCNTs (Si-G-SW) exhibited the highest specific capacity (829.7 mAh g−1 at 0.1 A g−1), rate capability, and cycle stability (>79% after 100 cycles). We expect this robust 3D network electrode system to provide a new route for high-energy-density LIB anodes.