Sökning: "Disordered carbon"

Visar resultat 1 - 5 av 27 avhandlingar innehållade orden Disordered carbon.

  1. 1. Lignin- and PAN-based carbon fibres as negative electrodes for alkali-ion batteries

    Författare :Kevin Peuvot; Göran Lindbergh; Dan Zenkert; Enn Lust; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; hard carbon; lithium-ion batteries; sodium-ion batteries; potassium-ion batteries; lignin-based carbon fibres; PAN-based carbon fibres; free-standing electrodes; Chemical Engineering; Kemiteknik;

    Sammanfattning : The development of sodium-ion batteries (SIBs) and potassium-ion batteries (KIBs) have accelerated since they can now reach similar gravimetric energy densities as lithium-ion batteries (LIBs) but with a lower environmental impact. Hard carbon is the most common negative electrode for SIBs and KIBs and can be made from renewable resources such as lignin. LÄS MER

  3. 2. Synthesis and characterization of nanocarbons as reinforced particles in metal composites

    Författare :Vicente Benavides; Alberto Vomiero; Frank Mücklich; Olga Chernogorova; Jordi Ibañez Inza; Luleå tekniska universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Nanocarbons; super elastic hard carbon; Fullerenes under pressure; Disordered carbon; Experimentell fysik; Experimental Physics;

    Sammanfattning : In this work, several scientific problems related to high pressure–high temperature (HP–HT) synthesis of new materials using fullerite as a precursor were studied: first, the mechanism of the transformation of C60 crystal into a nano-clustered graphene phase (NGP) at a pressure of 8 GPa; and second, the effect of disorder introduced into C60 crystals by ball milling prior to HP–HT synthesis on the structure and properties of the NGP. A separate set of experiments was devoted to compression of C60 precursor at unexplored before pressure of 25 GPa and elevated temperatures in search for new type of disordered carbon-based materials. LÄS MER

  4. 3. Electrocatalysts for sustainable hydrogen energy : disordered and heterogeneous nanomaterials

    Författare :Joakim Ekspong; Thomas Wågberg; Ludvig Edman; Tomas Edvinsson; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Water splitting; Electrochemistry; Nanomaterials; Density functional theory; Hydrogen evolution; MoS2; Fuel cell; nanomaterials; nanomaterial; fysik; Physics; Physical Chemistry; fysikalisk kemi;

    Sammanfattning : With the current global greenhouse gas emissions, our remaining carbon budget is depleted in only 7 years. After that, several biophysical systems are predicted to collapse such as the arctic ice, coral reefs and the permafrost, leading to potentially irreversible consequences. LÄS MER

  5. 4. Biobased carbon fibers from solution spun lignocellulosic precursors

    Författare :Andreas Bengtsson; Monica Ek; Maria Sedin; Elisabet Brännvall; Elisabeth Sjöholm; Johannes Ganster; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; Carbon fiber; Carbonization; Cellulose; Kraft pulp; Softwood kraft lignin; Solution spinning; Stabilization; Barrvedslignin; Cellulosa; Karbonisering; Kolfiber; Lösningsmedelsspinning; Stabilisering; Sulfatmassa; Fiber- och polymervetenskap; Fibre and Polymer Science;

    Sammanfattning : Carbon fibers (CFs) have excellent mechanical properties and a low density, making themattractive as a reinforcing fiber in composites. The use of CFs is limited to high-end applications,since they are produced from an expensive fossil-based precursor via an energy-intensivemanufacturing process, explaining the need for cheaper CFs from renewables. LÄS MER

  7. 5. Disordered Icosahedral Boron-Rich Solids : A Theoretical Study of Thermodynamic Stability and Properties

    Författare :Annop Ektarawong; Björn Alling; Michael Widom; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Icosahedral boron-rich solids; Boron carbide; Configurational disorder; First-principles calculations; Thermodynamic stability; Superatom-special quasirandom structure;

    Sammanfattning : This thesis is a theoretical study of configurational disorder in icosahedral boron-rich solids, in particular boron carbide, including also the development of a methodological framework for treating configurational disorder in such materials, namely superatom-special quasirandom structure (SA-SQS). In terms of its practical implementations, the SA-SQS method is demonstrated to be capable of efficiently modeling configurational disorder in icosahedral boron-rich solids, whiles the thermodynamic stability as well as the properties of the configurationally disordered icosahedral boron-rich solids, modeled from the SA-SQS method, can be directly investigated, using the density functional theory (DFT). LÄS MER