In situ fabrication of dual coating structured SiO/1D-C/a-C composite as high-performance lithium ion battery anode by fluidized bed chemical vapor deposition

Abstract

To notably improve the cycling stability of high-capacity SiO anode, an ingenious carbon dual coating structure was proposed, utilizing the high conductivity of 1D carbon (1D-C) and the excellent buffering of amorphous carbon (a-C). The carbon deposition pattern by regulating process temperatures was explored. An evolutive carbon deposition mechanism between 1D-C and a-C was deduced, which was a competitive mode between low-temperature catalytic growth and high-temperature pyrolysis deposition. Motivated by the deduced carbon deposition mechanism, a novel two-step coating process via fluidized bed chemical vapor deposition was proposed to fabricate the SiO/1D-C/a-C composite. The grown thickened 1D-C and deposited a-C were heterogeneously coated on the SiO particle surface, forming an ingenious dual coating structure. The synthesized SiO/1D-C/a-C exhibited extremely significant enhanced cycling stability, which showed a reversible capacity of 1012 mAh g−1 (capacity retention of 88.3%) after 120 cycles. The thickened 1D-C is entangled with each other to form a three-dimensional conductive network, while the deposited a-C formed a shell-like coating to buffer the volume expansion during cycling. The unique carbon dual coating structure achieved synergistic strengthening, which guarantees the superior electrochemical performance of the SiO/1D-C/a-C.