Browsing by Author "Sha, Junwei"

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    Facile preparation of carbon nanotube hybrid materials by catalyst solutions
    (2024-08-13) Tour, James M.; Salvatierra, Rodrigo Villegas; Zakhidov, Dante; Sha, Junwei; Rice University; United States Patent and Trademark Office
    Embodiments of the present disclosure pertain to methods of making a carbon nanotube hybrid material by depositing a catalyst solution onto a carbon-based material, and growing carbon nanotubes on the carbon-based material such that the grown carbon nanotubes become covalently linked to the carbon-based material through carbon-carbon bonds. The catalyst solution includes a metal component (e.g., iron) and a buffer component (e.g., aluminum) that may be in the form of particles. The metal component of the particle may be in the form of a metallic core or metallic oxide core while the buffer component may be on a surface of the metal component in the form of metal or metal oxides. Further embodiments of the present disclosure pertain to the catalytic particles and carbon nanotube hybrid materials. The carbon nanotube hybrid materials of the present disclosure may be incorporated as electrodes (e.g., anodes or cathodes) in energy storage devices.
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    Rivet Graphene
    (American Chemical Society, 2016) Li, Xinlu; Sha, Junwei; Lee, Seoung-Ki; Li, Yilun; Ji, Yongsung; Zhao, Yujie; Tour, James M.; NanoCarbon Center
    Large-area graphene has emerged as a promising material for use in flexible and transparent electronics due to its flexibility and optical and electronic properties. The anchoring of transition metal nanoparticles on large-area single-layer graphene is still a challenge. Here, we report an in situ preparation of carbon nano-onion-encapsulated Fe nanoparticles on rebar graphene, which we term rivet graphene. The hybrid film, which allows for polymer-free transfer and is strong enough to float on water with no added supports, exhibits high optical transparency, excellent electric conductivity, and good hole/electron mobility under certain tensile/compressive strains. The results of contact resistance and transfer length indicate that the current in the rivet graphene transistor does not just flow at the contact edge. Carbon nano-onions encapsulating Fe nanoparticles on the surface enhance the injection of charge between rivet graphene and the metal electrode. The anchoring of Fe nanoparticles encapsulated by carbon nano-onions on rebar graphene will provide additional avenues for applications of nanocarbon-based films in transparent and flexible electronics.
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    Three-dimensional (3D) printing of graphene materials
    (2024-04-30) Tour, James M.; Sha, Junwei; Li, Yilun; Miller, Jordan; Kinstlinger, Ian; Cofer, Savannah; Chyan, Yieu; Rice University; United States Patent and Trademark Office
    Three-dimensional (3D) printing of graphene materials and methods and apparatuses for making same. In some embodiments, combined metal powder and carbon growth sources (such as powder Ni and sucrose) are utilized in the 3D printing process. In other embodiments, metal powders with binders (such as powder Ni and a polymer bases binder) are utilized in the 3D printing process. The metal in the resulting 3D printed composite material can then be etched or otherwise removed yielding the 3D printed graphene materials.