Multiwalled carbon nanotube webs welded with Si nanoparticles as high-performance anode for lithium-ion batteries

Si nanoparticles uniformly welded in multiwalled carbon nanotube (MWCNT) webs with 20 nm carbon layer was synthesized by a layer-by-layer (LBL) self-assembled modification approach, electrostatic attraction directed self-assembly method, in-situ chemical polymerization reaction and then subsequent carbonization process. The uniform and effective carbon layer on electrode surface transmitted sufficient electrons, and the deformation pressure from charge/discharge process was buffered. The special three-dimensional framework could afford better mechanical strength to deter the fracture and pulverization of the electrode structure for repeated cycling, which helped keep the electrode integrity and improve the electric conductive network. The as-prepared electrode showed a steady reversible capacity of 1067 mAh g −1 with a fading rate of 0.066%/cycle after 200 cycles and 937 mAh g −1 with a fading rate of 0.053%/cycle over 450 cycles and high rate capability of 721 mAh g −1  at 7 A g −1 .