Plasma-enhanced chemical vapor deposition for fabrication of yolk-shell SnO2@Void@C nanowires, as an efficient carbon coating technique for improving lithium-ion battery performance

This manuscript describes the implementation of plasma-enhanced chemical vapor deposition (DC-PECVD) and vapor-liquid-solid (VLS) techniques to fabricate a yolk-shell SnO2@Void@C nanowire (NW) structure. SnO2 nanowires have been synthesized on the stainless steel mesh substrate through the VLS method. The PECVDassisted growth of carbon nanolayer on the SnO2 and SiO(2 )coated SnO2 NWs has been performed to fabricate SnO2@C core-shell and SnO2@SiO2@C yolk-shell structures, respectively. A consequent silica etching process converted the SnO2@SiO2@C into SnO2@Void@C structure. The electrochemical performance of bare SnO2 NWs, SnO2 NWs @ C, and SnO2 @Void @ C coaxial NWs structures have been investigated in half cell Lithium ion battery (LIB) coin cells. A noticeable electrochemical enhancement has been observed for the SnO2@Void@C electrode, with a specific capacity of 723 mAh g(-1) at 0.2C current density after 100 cycles of charge/discharge, compared to 34 and 455 mAh g(-1) for SnO2 NWs and SnO2@C NWs, respectively. This significant improvement can be related to the stable SEI formation on the carbon-coated layer and the electrolyte interface. Besides, the proper void volume created between the SnO2 NWs and the carbon layer provides sufficient space for expanding the SnO2 NWs during the lithiation process. Moreover, the adequate electrical and ionic conductivity of the deposited carbon layer can improve the electrochemical performance of the fabricated anode material. Using PECVD for deposition of the carbon nanolayer benefits from being highly controllable and manageable, as well as its scalability for industrial application. Furthermore, the utilized approach is fast, inexpensive, and low temperature. The reported carbon coating process is proposed as an effective method for protecting the active electrode materials, and as a result, enhancing the performance of lithium-ion batteries.