High-Performance Li-Ion Battery Anodes Based on Silicon-Graphene Self-Assemblies

A series of Si/graphene sheet/carbon (Si/GS/C) composites was prepared by electrostatic self-assembly between amine-grafted silicon nanoparticles (SiNPs) and graphene oxide (GO). The Si/GS derived from carbonization of Si/GO assemblies showed limited cycling stability owing to loose cohesion between...

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Bibliographic Details
Published in:Journal of the Electrochemical Society 2017-01, Vol.164 (1), p.A6075-A6083
Main Authors: Kim, Nahyeon, Oh, Changil, Kim, Jaegyeong, Kim, Jeom-Soo, Jeong, Euh Duck, Bae, Jong-Seong, Hong, Tae Eun, Lee, Jung Kyoo
Format: Article
Language:English
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Summary:A series of Si/graphene sheet/carbon (Si/GS/C) composites was prepared by electrostatic self-assembly between amine-grafted silicon nanoparticles (SiNPs) and graphene oxide (GO). The Si/GS derived from carbonization of Si/GO assemblies showed limited cycling stability owing to loose cohesion between SiNPs and graphene, and increased impedances during cycling. To counteract the cycling instability of Si/GS, an additional carbon-gel coating was applied to the Si/GO assemblies in situ in solution followed by carbonization to yield dense three-dimensional particulate Si/GS/C composite with many internal voids. The obtained Si/GS/C composites showed much better electrochemical performances than the Si/GS owing to enhanced cohesion between the SiNPs and the carbon structures, which reduced the impedance buildup and protected the SiNPs from direct exposure to the electrolyte. A strategy for practical use of a high-capacity Si/GS/C composite was also demonstrated using a hybrid composite prepared by mixing it with commercial graphite. The hybrid composite electrode showed specific and volumetric capacities that were 200% and 12% larger, respectively, than those of graphite, excellent cycling stability, and CEs (>99.7%) exceeding those of graphite. Hence, electrostatic self-assembly of SiNPs and GO followed by in situ carbon coating can produce reliable, high-performance anodes for high-energy LIBs.
ISSN:0013-4651
1945-7111
DOI:10.1149/2.0101701jes