Activated natural porous silicate for a highly promising SiO_xnanostructure finely impregnated with carbon nanofibers as a high performance anode material for lithium-ion batteries

Abstract

A highly promising anode material with an amorphous SiO x nanostructure finely impregnated with carbon nanofibers is presented. The nanostructure material has a unique integral feature in that carbon nanofibers smaller than several nm in diameter are finely dispersed in amorphous SiO x media in an aligned manner. The synthetic route to fabricate the nanostructure is very simple and easy, using natural porous silicate, sepiolite, activated through the process of sintering and acid treatments on carbon source-loaded sepiolite nanocomposites. Upon the treatments, the nanocomposite material is changed in respect of its structure and chemical composition from crystalline Mg silicate to the carbon nanofiber-impregnated amorphous SiO x phase (CNF-SiO x nanostructure), and the electrochemical activity is greatly improved. The CNF-SiO x nanostructure exhibits excellent electrochemical performance with a reasonably high capacity of approximately 720 mA h g À1 for a current density of 70 mA g À1 (C/10 rate) and outstanding rate capability with a capacity retention of 96.8% for a current density of 700 mA g À1 and 87% at 1400 mA g À1 relative to that at 35 mA g À1 , even at a high electrode loading level above 8 mg cm À2 . The cycling performance is also very stable, with a capacity retention of 94.7% over 50 cycles at a rate of 350 mA g À1 and with a Coulombic efficiency above 99%.

Ternary Sulfur/Polyacrylonitrile/SiO2 Composite Cathodes for High-Performance Sulfur/Lithium Ion Full Batteries

“…The S 2p 1/2 peak at 164.6 eV was assigned to the S-S bond [21]. In XPS spectrum of Si 2p (Figure 3d), the peak at 104.8 eV was also present in the characteristic peak of SiO 2 [36]. These data were in accordance with the XRD patterns.…”

Facile synthesis and stable cycling ability of hollow submicron silicon oxide–carbon composite anode material for Li-ion battery

“…At the high rate of 5C, the composite still delivers a discharge capacity of 200 mAh/g. This cycling stability and rate-performance are greater than or comparable to those of carbon-coated SiO 2 nanoparticles or composites of nano-SiO x and carbon [5,7,12,[28][29][30][31]. Such high stable cycling ability is ascribed to the significance of a homogenous mixing (dispersion) of silicon oxide and carbon and a unique hollow microstructure with inner free space, which enable to provide improved electric conductivity and a homogeneous current distribution, and to accommodate the large volume change of silicon with lithiation-delithiaiton cycling.…”

“…In the reverse process, a broad anodic peak at 0.2-0.6 V is by delithiation of Li x Si reproducing amorphous Si. The composite electrode exhibits a typical cycling behavior of amorphous silicon oxide [20,21,[28][29][30][31]. After the initial cycle, the cathodic and anodic capacities increase.…”

Glucose hydrothermal encapsulation of carbonized silicone polyester to prepare anode materials for lithium batteries with improved cycle stability

“…51,52 During the anodic polarization of the first cycle, the insignificant anodic peak at 0.35 V is de-lithiation of Li x Si phase. 53,54 Fig. S6† shows Nyquist plots for the six samples (SiO x /C, SiO x /C-rGO-0, SiO x /C-rGO-1, SiO x /C-rGO-2, SiO x /C-rGO-3, SiO x /C-rGO-4).…”