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Superior Lithium-Ion Storage Properties of Si-Based Composite Powders with Unique Si@Carbon@Void@Graphene Configuration

Cited 26 time in Web of Science Cited 27 time in Scopus
Authors
Choi, Seung Ho; Jung, Dae Soo; Choi, Jang Wook; Kang, Yun Chan
Issue Date
2015-01
Citation
Chemistry - A European Journal, Vol.21 No.5, pp.2076-2082
Keywords
BatteriesEnergy efficiencyGrapheneNanoparticlesSpray pyrolysis
Abstract
Composite powders of the configuration Si@carbon@void@graphene were prepared by a one-step spray pyrolysis process, by adding polyvinylpyrrolidone (PVP) to a precursor solution containing graphene oxide (GO) sheets and silicon nanoparticles (NPs). Morphological analysis indicates that the individual Si NPs are coated with amorphous carbon and encapsulated in a micrometer-sized graphene ball structure that offers a large amount of buffer space. The addition of PVP improves the stability of the colloidal spray solution containing the GO sheets and the Si NPs. Consequently, the prepared Si@C@void@graphene composite powders have a relatively more uniform morphology than the Si@void@graphene composite powders prepared from the spray solution without PVP. The first charge and dis-charge capacities of the Si@C@void@graphene electrode measured at 0.1 Ag-1 are as high as 3102 and 2215 mA h g(-1), respectively. With an increase in the current rate from 0.5 to 11 Ag-1, 46% of the original capacity (i.e., 2134 mA h g(-1)) is maintained. After 500 cycles at a high rate of 7 Ag-1, the Si@C@void@graphene electrode shows 84% capacity retention and 99.8% of the average Coulombic efficiency. The superior cycling and rate capabilities of the prepared Si@C@void@graphene electrode could be attributed to the uniform carbon coating of the Si NPs and the graphene ball structure, which facilitates efficient diffusion of Li ions and prevents the penetration of electrolyte into graphene ball during cycling.
ISSN
0947-6539
URI
https://hdl.handle.net/10371/164643
DOI
https://doi.org/10.1002/chem.201404981
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College of Engineering/Engineering Practice School (공과대학/대학원)Dept. of Chemical and Biological Engineering (화학생물공학부)Journal Papers (저널논문_화학생물공학부)
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