title: Graphene Coating of Silicon Nanoparticles with CO2 -Enhanced Chemical Vapor Deposition.
abstract: Understanding the growth of graphene over Si species is becoming ever more important as the huge potential for the combination of these two materials becomes more apparent, not only for device fabrication but also in energy applications, particularly in Li-ion batteries. Thus, the drive for the direct fabrication of graphene over Si is crucial because indirect approaches, by their very nature, require processing steps that, in general, contaminate, damage, and are costly. In this work, the direct chemical vapor deposition growth of few-layer graphene over Si nanoparticles is systematically explored through experiment and theory with the use of a reducer, H2 or the use of a mild oxidant, CO2 combined with CH4 . Unlike the case of CH4 , with the use of CO2 as a mild oxidant in the reaction, the graphene layers form neatly over the surface and encapsulate the Si particles. SiC formation is also prevented. These structures show exceptionally good electrochemical performance as high capacity anodes for lithium-ion batteries. Density functional theory studies show the presence of CO2 not only prevents SiC formation but helps enhance the catalytic activity of the particles by maintaining an SiOx surface. In addition, CO2 can enhance graphitization.
authors.affiliation: Energy Material Lab, Material Research Center, Samsung Advanced Institute of Technology, Samsung Electronics Co. Ltd., 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do, 443-803, Republic of Korea.
authors.forename: In Hyuk
authors.initials: IH
authors.lastname: Son
authors.affiliation: Energy Material Lab, Material Research Center, Samsung Advanced Institute of Technology, Samsung Electronics Co. Ltd., 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do, 443-803, Republic of Korea.
authors.forename: Jong Hwan
authors.initials: JH
authors.lastname: Park
authors.affiliation: School of Urban, Architecture and Civil Engineering, Pusan National University, 2, Busandaehang-ro 63 beon-gil, Geumjeong-gu, Busan, 46241, Republic of Korea.
authors.forename: Soonchul
authors.initials: S
authors.lastname: Kwon
authors.affiliation: Graduate School of Energy, Environment, Water and Sustainability (EEWS), Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 305-701, Republic of Korea.
authors.forename: Jang Wook
authors.initials: JW
authors.lastname: Choi
authors.affiliation: College of Physics, Optoelectronics and Energy and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou, 215006, China.|Leibniz-IFW Dresden, Helmholtzstrasse 20, Dresden, 01069, Germany.|Centre of Polymer and Carbon Materials, Polish Academy of Sciences, M. Curie-Sklodowskiej 34, Zabrze, 41-819, Poland.
authors.forename: Mark H
authors.initials: MH
authors.lastname: Rümmeli
keywords: CO2; Si nanoparticles; chemical vapour deposition; electrochemistry; graphene