Nano structure of low crystallinity carbon materials analyzed by using high energy X-ray diffraction

Oshida, Kyoichi; Nakazawa, Takahiro; Osawa, Kozo; Endo, Morinobu

doi:10.2478/s11534-009-0028-6

Cited by 4 publications

(2 citation statements)

References 8 publications

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“…1(A)). XRD thus indicates that the carbons are amorphous, 34 which is consistent with previous reports for amorphous HTC carbon. 17 The reflection at higher scattering angles is typically found in amorphous materials (e.g.…”

Section: Resultssupporting

confidence: 90%

Hierarchical porous carbonaceous materials via ionothermal carbonization of carbohydrates

et al. 2011

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Section: Resultssupporting

confidence: 90%

Hierarchical porous carbonaceous materials via ionothermal carbonization of carbohydrates

et al. 2011

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“…the atomic coordination spheres they reflect, start losing their sharpness leading to a reduction of the length of structural coherence, measured by the real space distance at which the PDF data decay to zero, to only 20-30Å. Indeed the atomic PDFs for graphitic carbon milled for 70-1270 min resemble very much those of low crystallinity carbon obtained by a thermal decomposition of organic precursors [17,18]. The graphitic planes in those low crystallinity carbon are found to be rich in structural defects and heavily buckled [17].…”

Section: Discussionmentioning

confidence: 99%

Li insertion in ball-milled graphitic carbon studied by total x-ray diffraction

Petkov

Timmons

Camardese

et al. 2011

J. Phys.: Condens. Matter

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Ball-milled graphitic carbon, both not and electrochemically lithiated, has been studied by total x-ray diffraction involving high-energy synchrotron radiation scattering and atomic pair distribution function analysis. The experimental data has been used to guide reverse Monte Carlo simulations of the three-dimensional structure of the not-lithiated samples. Experimental and modeling results show that ball milling for short times breaks the graphitic layers into smaller pieces as well as generates extended atomic vacancies. Those increase the overall ability of the material to accommodate lithium. Ball milling for longer times keeps generating even more atomic vacancies in the graphitic layers. Carbon atoms displaced from the layers, however, move in between the layers, turning heavily ball-milled graphitic carbon into an assembly of almost-fused-together, heavily buckled layers that have an impaired ability to accommodate Li atoms. This helps explain well the initial substantial increase and then decrease in the Li storage capacity of ball-milled graphitic carbon. The study demonstrates the great ability of total x-ray diffraction to provide precise structural information for complex materials that are being increasingly explored for energy applications.

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