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Colóquios do IF-UFF

Sala A2-07, 18/2013, 11h

Palestrante: prof. Dr. Hui-Ming Cheng (Chinese Academy of Science)

Título: Fabrication and applications of graphene-based materials

There are challenges of how to realize large-scale fabrication of high-quality graphene structures and large-size single crystal graphene domains, which are essential for mass applications and device applications since grain boundaries are believed to markedly degrade the quality and properties of graphene.
We developed an ambient pressure CVD to synthesize millimeter-size single crystal graphene grains and films on Pt substrates, and an electrochemical bubbling method to transfer these grains and films, which is also nondestructive to the Pt substrates that can be repeatedly used for graphene growth with no limit [1]. The single crystal graphene grains has high crystallinity and high electrical mobility. Second, in order to obtain graphene in a relatively large quantity, we tried to use Ni particles [2] and Ni foams [3] as substrates. Interestingly, with a Ni foam as template, a 3D graphene macrostructure, which is called graphene foam (GF), can be synthesized [3]. This porous graphene bulk material consists of an interconnected network of graphene, is flexible, and has outstanding electrical and mechanical properties. And it can be used in elastic conductors [3], sensors [4], flexible lithium ion batteries [5], and electromagnetic interference fielding materials [6]. Finally, in order to commercialize graphene materials, we developed a solid state intercalation-high temperature expansion-liquid phase exfoliation process [7]. With a proto-type production line, 5 kg/day high-quality graphene material with high electrical conductivity can be directly produced, which will have wide applications in composites, energy storage, conductive inks, etc.

Acknowledgement  Financial support from NSFC, MOST and CAS is acknoledged.

1. L. Gao, et al, Repeated growth and bubbling transfer of graphene with millimeter-size single crystal grains using platinum, Nature Communications 3:699, 2012, DOI: 10.1038/ncomms1702.
2. Z. P. Chen, et al, Bulk growth of mono- to few-layer graphene on nickel particles by chemical vapor deposition from methane, Carbon 48 (12), 2010, p.3543-3550.
3. Z. P. Chen, et al, Three-dimensional flexible and conductive interconnected graphene networks grown by chemical vapour deposition, Nature Materials 10, 2011, p. 424-428.
4. F. Yavari, Z. P. Chen, et al, High senstitivity gas dection using a macroscopic three-dimensional graphene network, Scientific Reports 1 166 2011, DOI: 10.1038/srep00166.
5. N. Li, et al, Lightweight and flexible graphene-based lithium ion batteries with ultrafast charge and discharge rates, PNAS, 109 (43), 2012, 17360-17365.
6. Z. P. Chen, et al, Lightweight and flexible graphene foam composites for high-performance electromagnetic interference shielding, Adv Mater  25 (9), 2013, 1296-1300.
7. S. F. Pei, et al, A method for fabricating high-quality graphene material, China Patent filed No. 201110282370.5, 2011.