Dixon, D.

Ehrenberg, H.

Melke, J.

Roth, C.

Öhl, J.

English

KITopen

KIT – University of the State of Baden-Wuerttemberg andNational Research Center of the Helmholtz AssociationInvestigation of carbon materials in energy storage applications by x-ray Raman scattering and optical Raman spectroscopy Julia Melke, Ditty Dixon, Johannes Öhl, Helmut Ehrenberg, Christina RothInstitute of Applied Materials IntroductionResultsFigure 1. (A) Lithium-ion battery with an intercalation electrode. (B) Vanadium redox-flow battery and (C) H2/O2 polymer electrolyte fuel cell. [adapted fromWinter et al Adv. Mater. 1998 10(10) p.725-763.]Disorder obtained by Raman spectroscopyFigure 3. The Raman spectra (λ=514nm) of graphite shows the typical G-band [1580 cm-1] and the disorder induced D-band [1350 cm-1]. These bands are also observed for the other materials but broadened. The peak area ratio D/G determines the disorder in the materials and increases in the following order:Graphite>Vulcan>Graphite oxide (GO). D                 G          D/GGraphite     15649 82798      0.2GO 46685 10619 4.4Vulcan        2738 2201      1.2X-ray Absorption Spectroscopy Carbon materials are of utmost importance in energy storage applications (Fig. 1). However their structure –performance relationship is poorly understood. Figure 4. The C-K-edge was measured in TEY. The spectra of carbon black and graphite show the π*-feature at around 285.1 eV and the σ*-feature at around 292 eV as known for graphitic materials. But compared to the nanoparticle graphite the carbon black shows additional features at 288.3 eVwhich was also found for PVA and at 290 eV which is observed for diamond nanoparticles. This experiment has been done at the SIM Beamline, SLS.X-ray Raman Scattering (XRS)Figure 5. The XRS spectra for graphite, Vulcan and graphite oxide are displayed. All three samples show the π*-feature at 284 and the σ*-feature at around 290 eV. For graphite we found a larger π*-resonance compared with the NEXAFS data. The opposite behaviour is observed for Vulcan whereas  the graphite oxide data are similar. X-ray Raman scattering measurement have been performed at the SuperXAS Beamline, SLS using the X-ray emission spectrometer. The scattered X-rays were detected at Es=8.047 keVwhile the incident energy E was scanned from 8.322 – 8.36 keV.We gratefully acknowledge C. Wäckerlin, O. Safonova, G. Smolentsev, A. Kleibert, J. Girovsky and N. Ballav for their help in performing these experiments.Figure 2. Scanning electron microscopy images of the different samples, graphite (A), Vulcan XC72 (B) and graphite oxide (C)Materials investigated:A B C

Investigation of carbon materials in energy storage applications by x-ray Raman scattering and optical Raman spectroscopy

https://publikationen.bibliothek.kit.edu/220092523/3816352

Investigation of carbon materials in energy storage applications by x-ray Raman scattering and optical Raman spectroscopy

Abstract

Similar works

Full text

Available Versions

KITopen