AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
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Electrochemical Performance of Multi-Layer Graphene-Carbon Nanoflower Composite Synthetized by Aerosol Based Methods
Mirella Miettinen, Anna Lähde, Tiina Torvela, Tommi Karhunen, Juho Välikangas, Ulla Lassi, JORMA JOKINIEMI, University of Eastern Finland, Kuopio, Finland
Abstract Number: 304 Working Group: Nanoparticles and Materials Synthesis
Abstract Different carbon nanomaterialshave been synthesized eagerly during the past years because they may result in more efficient materials for energy applications, such as supercapacitors or lithium-ion batteries. The aerosol based synthesis of a multi-layer graphene-carbon nanoflower composite (MLG/CNF) is previously reported (Miettinen et al., 2014). The starting material was synthetized from hexamethyldisilane (HMDS) by the atmospheric pressure chemical vapor synthesis (APCVS). The resulting Si-C material was then annealed at high temperature induction furnace to obtain multi-layer graphene-carbon nanoflower composite. Here,structureand electrochemical performance of the composite was studied.
The structure of the MLG/CNF composite was studied with an aberration corrected high-resolution transmission electron microscope (TEM, JEOL JEM-2200FS). The analyses were performed at electron acceleration voltage of 80 kV.Selected area diffraction analysis (SAED) wasperformed from the MLG sheets. For the electrochemical testing,as prepared powder was sieved (> 45 μm) to remove residual SiC crystals and electrodes were prepared using conventional method. Electrochemical performance of the MGL/CNF compositewas tested in Li-ion button cells against graphite reference.
SAED analysis showed that graphene layers were rotated to each other. The most common rotation angle in the MLG sheets was 30 ± 2°, but also other rotation angles were detected (Miettinen et al., 2015). Due to rotational faults the interlayer distance in the sheets was increased ~12 % compared with graphite. The CNFs contained nanosize cavities. The wrinkled network of the MLG sheets and the CNFs may increase, e.g., lithium-ion insertion capacity of the composite. The electrochemical performance of the MLG/CNF composite was better than graphite reference.
Miettinen, M., Hokkinen, J., Karhunen, T., et al. (2014) J. Nanopart. Res., 16, 2168.
Miettinen, M., Torvela, T., Pfüller, C., et al. (2015) Carbon, 84, 214-224.