3-D vertically aligned few layer graphene – partially reduced graphene oxide/sulfur electrodes for high performance lithium–sulfur batteries

Abstract

3D electrodes comprising of vertically-aligned, few-layered graphene, melt impregnated with partially reduced graphene oxide/sulfur nanocomposites (3D FLG/PrGO/S) are reported for high performance (1040 mA h g−1) Li–S batteries.

Vertically Aligned Few-Layered Graphene-Based Non-Cryogenic Bolometer

“…Previous characterizations including electron microscopy, X-ray diffraction and Raman spectroscopy have conclusively proved that the synthesized structures are made up of highly graphitized sheets with a few layers of graphene on the edges. An in-depth explanation of the structure and the corresponding growth mechanism can be found in our earlier works [26][27][28][29]. This unique morphology is a cumulative effect of the internal stress-inducing factors and electrical self-bias field which is imposed on the substrate surface from the plasma environment [30,31].…”

“…The corresponding resistance recorded at the normal condition was~1.8 KΩ. The typical Raman spectra of graphene and few-layered graphene-like systems exhibit at least three to four major bands, denoted as D (~1330 cm −1 ), G (~1580 cm −1 ), D′ (~1620 cm −1 ) and G′ (~2660 cm −1 ) [26][27][28][29][30][31]. As seen in Figure 2c, all these bands were clearly distinguished and observed for the VAG samples.…”

“…As seen in Figure 2c, all these bands were clearly distinguished and observed for the VAG samples. The Raman spectra were further analyzed for their band shape and full-width at half-maximum (FWHM) parameters, in accordance with our previous work, using Lorentzian peak shapes for D, G and G′ (2D) bands, and a Gaussian peak for the D′ band [26][27][28][29][30][31]. While the low FWHM (~25 cm −1 ) of the G band is indicative of a high degree of graphitisation, the narrow FWHM of the G′ (2D) band along with the absence of a graphitic shoulder is further confirmed as one of the indicators of a few-layered graphene (FLG) system ( Figure 2) [28][29][30][31].…”

“…During the growth, the microwave power was raised to 800 W and maintained during the growth period of 60 s. The samples were then allowed to cool down under a constant N 2 flow. Further details of the experimental setup can be found in our earlier reported works [26][27][28][29].…”

“…The size of the platelets varied from ~100 nm to ~2 μm. The platelet tip consisted of 5-10 layers of graphene, while the base of the platelet was thicker, perhaps consisting of 10-20 layers [26][27][28][29]. These nanoflakes were essentially vertically stacked two-dimensional graphene sheets growing from the underlying substrate and terminating into open graphitic-edge planes.…”