Thin-Film SiOx Coated Carbon Nanofibers As Stable Anodes for Lithium-Ion Batteries

Abstract

With the increase in the capacity of cathode materials in lithium-ion batteries(LIBs), the demand for novel anode materials with high theoretical energy density is following. Up to now, many candidates have been reported; silicon-based composites are considered a prospective alternative due to their abundant reserves and high energy density. However, The primary disadvantage of Si, electrochemical irreversibility during the charge/discharge process, hinder widespread use.In this study, we adapted SiOx-coated carbon nanofibers (SiOx-CNFs) composite to the binder-free anode current collector for lithium-ion batteries. The composite has a structure where a thin amorphous SiOx (thickness ~100nm) is coated on the CNFs surface and is successfully synthesized by electrospinning and sputtering. This structure, surface SiOx-coated porous CNF, breaks through the significant drawback of Si-based composites, pulverization of Si element during the charge/discharge cycle. In addition to this, due to the structure of porous CNF, we achieved the curtail of electrode weight.Scanning Electron Microscopy (SEM) and X-ray diffraction (XRD) analyses are carried out to confirm the morphology and crystallinity. Furthermore, with cyclic voltammetry analysis, fast reaction kinetics and excellent electrochemical reversibility are verified. The cycle test is also conducted to prove excellent capacity and cyclic stability.