Three-dimensional assembly of multiwalled carbon nanotubes for creating a robust electron-conducting network in silicon-carbon microsphere-based electrodes

We present a strategic approach to improve the cycle performance of a polymeric binder-free anode based on nano-Si@C microspheres by incorporating a multiwalled carbon nanotubes (MW-CNTs) network and performing carbodiimide-based condensation coupling to form a robust molecular-junction between MW-CNTs and nano-Si@C microspheres. Field-emission scanning electron microscopy reveals that one-dimensional MW-CNTs homogeneously wrapped the individual Si@C microspheres and they interwove through the intergranular nanospace. The incorporation of amide bonds at the junction primarily contributes to the stabilization and reinforcement of the hybrid electrodes. Their reversible capacity after 50 cycles with 0.5 A g(−1) was significantly improved from 81 mAh·g(−1) to 520 mAh·g(−1). Such robustness associated with the supramolecularly assembled MW-CNTs is expected to facilitate electron conductivity and mass transfer kinetics, leading to enhanced electrochemical performance of the Si@C anode.