The synthesis of fluorinated reduced graphene oxide (F-rGO) by direct fluorination of reduced graphene oxide (rGO) with XeF2 or F2/BF3 in aHF is reported in this paper. Characterization performed by HAADF-STEM and NMR confirm the formation of C–F bonds, which is also suggested by the color change from graphite grey to light yellow. F-rGO has been used as an interlayer additive supported by a glass fiber separator in lithium-sulfur (Li-S) batteries Electrochemical cycling of Li-S batteries has confirmed the beneficial role of F-rGO separators.
COBISS.SI-ID: 29021479
In this paper we demonstrate UV-Vis spectrophotometry as a powerful analytical method for the in-situ quantitative and qualitative determination of polysulphides formed during Li-S battery operation. The quantitative and the qualitative calibration were done based on carefully synthesised polysulfides. Paper was, according to the journal editor, one of the most accessed articles in ChemSusChem in august 2013.
COBISS.SI-ID: 5280026
We demonstrate an importance of the effective separation between the sulphur cathode and the lithium anode in Li-S batteries. Improved cycling stability was obtained by using fluoro functionalized reduced graphene oxide (rGO) between the sulphur cathode and the lithium anode. The thickness of hydrophobic interlayer was found to be 1-2 micro meter. The possible mechanism checked with analytical techniques suggested that improvement in the capacity stability was attributed to the reduced reactivity of long chain polysulphides with the metallic lithium and to the homogenous distribution of end discharge products during cycling.
COBISS.SI-ID: 5504794
Understanding the mechanism(s) of polysulfide formation along with knowledge about the interactions of sulphur and polysulphides with a host matrix and electrolyte are essential for the development of long cycle life lithium sulphur (Li-S) batteries. To achieve this goal, new analytical tools need to be developed. In this work we report about the sulphur K-edge XANES study and 6,7Li MAS NMR study on a Li-S battery and its sulphur components. The setup for in operando XANES measurements can be viewed as a valuable analytical tool that can aid in the understanding of the sulphur environment in Li-S batteries. Complementary information about the lithium species within the cathode were obtained by 7Li MAS NMR spectroscopy.
COBISS.SI-ID: 3284475
We prepared carbon substrates from different types of organic substances which can be prepared from biomass. Carbon substrates were prepared by salt melt sol gel synthesis method and used as substrates for the impregnation with sulphur. Their properties were studied in the Li-S batteries by using electrochemical characterization.
COBISS.SI-ID: 5771802