Novel 0D-Nanocarbon-Containing Ceramic Nanocomposites for Heat Dissipation and Thermoelectric Applications
Final Report Abstract
The main goal of this project was to develop novel multifunctional 0D- and 0D-2D-nanocarbonbased ceramic composites with well-defined nanostructures and tailored functional properties. These ceramic nanocomposites consist of nanodiamond (ND), onion-like carbon (OLC), core-shell bucky nanodiamond (OLC@ND or simply BND) or nanodiamond-graphene hybrid phases (ND@GO) i) homogeneously dispersed within a ceramic matrix (silica or silicon nitride) or ii) encapsulated within silica shell as core-shell particles. These new materials exhibit tailored / adjustable functional properties such as thermal and electrical conductivity. The sp2-hybridized nanocarbon-containing composites demonstrate a low thermal conductivity despite their enhanced electrical conductivity. The ceramic nanocomposites are easily accessible via sol-gel or polycondensation reactions of chemically functionalized nanocarbons, followed by pyrolysis of the as-obtained nanocarbon/polymer precursor composite. In the first 3 years of the project, it was successfully demonstrated that the developed ND-containing preceramic polymers (i.e., ND/polysiloxane, ND/polysilazane nanocomposites) can act as flexible precursor systems to access different nano carbon-containing ceramic nanocomposites (depending on processing/thermal treatment conditions), i.e. ND/ceramic, OLC@ND/ceramic and OLC/ceramic nanocomposites, based on the in-situ thermal graphitization of nanodiamond phase. Later on, an optimized route to high-yield and low-cost synthesis of OLC-SiO2 and OLC@ND-SiO2 ceramic nanocomposites was developed from precursors with different branching, Furthermore, the effect of full confinement of 0D-nanocarbons into silica nanoparticles (core-shell carbon-silica nanoparticles) was investigated. The synthesis of novel nanodiamond-graphene-hybrid containing silica composites, and their thermal conversion (from ND to OLC) was studied. Herein, the new 2D hybrid was compared with its 0D analogue OLC@ND where a direct evaluation graphene vs. fullerene, 2D vs. 0D sp2 C was established. Processing of ceramic composites as monoliths was performed bx hot pressing, yielding mesoporous pellets. In the second term pellets were produced by ultrafast pyrolysis and sintering technique. Thus, these “smart” oxide ceramic nanocomposites were designed to exhibit adjusted / adjustable structural properties in addition to functional properties such as tunable thermal and electrical conductivity. This study delivers valuable knowledge related to the relatively facile preparative approach, design and use of nanocarbon-based nanocomposites with adjustable properties for possible thermal management applications. Thus, electrically insulating nanocomposites with tunable thermal conductivity as function of nanodiamond content were developed as potential environmentally stable ceramic substrates for power devices. Moreover, the sp2-hybridized carbon-ceramic nanocomposites -exhibited low thermal conductivity and high electrical conductivity, interesting features for thermoelectric demands.
Publications
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Structure, energetics and bioactivity of silicon oxycarbide-based amorphous ceramics with highly connected networks. Journal of the European Ceramic Society, 38(4), 1311-1319.
Ionescu, Emanuel; Sen, Sabyasachi; Mera, Gabriela & Navrotsky, Alexandra
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Metal-catalyst-free access to multiwalled carbon nanotubes/silica nanocomposites (MWCNT/SiO2) from a single-source precursor. Dalton Transactions, 48(29), 11018-11033.
Mera, Gabriela; Kroll, Peter; Ponomarev, Ilia; Chen, Jiewei; Morita, Koji; Liesegang, Moritz; Ionescu, Emanuel & Navrotsky, Alexandra
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Polymer‐Derived Ceramics. Encyclopedia of Inorganic and Bioinorganic Chemistry, 1-26. Wiley.
Mera, Gabriela & Ionescu, Emanuel
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Novel 0D-nanocarbon-silica ceramic composites: sol–gel synthesis and high-temperature evolution. Dalton Transactions, 49(21), 7144-7154.
Ott, Alexander; Rogg, Simone; Lauterbach, Stefan; Kleebe, Hans-Joachim; Hess, Christian & Mera, Gabriela
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Chemical design of onion-like carbon-silicon diimide polymer composites. Experimental Results, 2.
Wang, Kaili & Mera, Gabriela
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Cover Story, Materials, Volume 14, Issue 15 (August-1) – 288 articles
Mera, Gabriela
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Preparation ofOnion-like Carbon-Silicon Diimide Polymer Composites v1. ZappyLab, Inc..
Wang, Kaili & Mera, Gabriela
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Structure and Thermodynamics of Silicon Oxycarbide Polymer-Derived Ceramics with and without Mixed-Bonding. Materials, 14(15), 4075.
Sugie, Casey; Navrotsky, Alexandra; Lauterbach, Stefan; Kleebe, Hans-Joachim & Mera, Gabriela
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Unraveling Na‐Ion Insertion Mechanisms in Polymer‐Derived SiCN(O) Ceramic via Operando Raman Spectroscopy. Batteries & Supercaps, 7(5).
Melzi, d.'Eril Marco; Kempf, Alexander; De Carolis, Dario M.; Graczyk‐Zajac, Magdalena Joanna; Mera, Gabriela & Riedel, Ralf
