Fabrication of Si/N-doped carbon nanotube composite via spray drying followed by catalytic chemical vapor deposition

Abstract

Developing an effective structure for the silicon-carbon composite that promotes electric-ionic conductivity and reduces the volume change is a key issue for Si-based anode. In this study, spherical granules comprising silicon nanoparticles (Si-NPs) grafted with nitrogen-doped carbon nanotubes (Si-NCNTs) are fabricated via spray drying followed by catalytic chemical vapor deposition (CCVD). The initial discharge and charge capacities of the Si-NCNTs are 2457 and 1820 mA h g−1, respectively. The Si-NCNTs shows a capacity retention of 57% after 200 cycles as well as improved rate capability when compared to the Si-NPs and commercial CNTs composites (Si-CNTs) fabricated via spray drying alone. The Li+ ion-diffusion-coefficient (DLi+) of the Si-NCNTs is approximately ∼three times larger than that of the Si-CNTs at critical lithiation potential. The NCNTs that form the interconnections between Si-NPs play the role of electrically conductive buffers that could accommodate the volume change produced and favor Li+ ion transport.