Fastly PECVD-Grown vertical carbon nanosheets for a composite SiOx-C anode material

Abstract

SiOx has been regarded as the most promising anode material for high energy density lithium-ion batteries (LIBs). However, SiOx materials suffer from intrinsic defects such as poor electrical conductivity, large volume expansion effects, and low initial Coulomb efficiency. In order to solve these problems, vertically arrayed carbon nanosheet encapsulated disproportionated-SiOx (d-SiOx@CNs) composites was fabricated by using a fast plasma-enhanced chemical vapor deposition (PECVD) processing. The PECVD produced vertically arrayed carbon nanosheets provided good interfacial contacts and significantly improved the electronic conductivity and Li+ diffusivity of the SiOx material. As LIBs anode, the d-SiOx@CNs composite displays a high reversible capacity (first charge/discharge capacity of 1456.7 and 1794.4 mAhg−1, respectively) and excellent cycling stability (capacity retention of 87.2 % after 200 cycles at a current density of 0.4 Ag−1). The full cell (d-SiOx@CNs15/G‖NCM811) assembled with the commercial NCM811cathode material also showed an excellent electrochemical performance (capacity retention rate of 76.3 % after 200 cycles at 1C current density) and provided a high energy density of 424.2 Wh kg−1. The fast-growth mechanism of the vertically oriented carbon nanosheet by PECVD was also analyzed in terms of the plasma characteristic.