Advanced anodes composed of graphene encapsulated nano-silicon in a carbon nanotube network

• Published in: RSC advances Vol. 7; no. 26; pp. 15694 - 15701
• Main Authors: Ding, Xuli, Wang, Haifeng, Liu, Xiaoxiao, Gao, Zhonghui, Huang, Yangyang, Lv, Danhui, He, Pengfei, Huang, Yunhui
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 2017
• Subjects: Anodes; Carbon nanotubes; Chemical synthesis; Chemical vapor deposition; Elasticity; Electrical resistivity; Electrochemical analysis; Electrode materials; Electrolytes; Encapsulation; Graphene; Lithium; Lithium-ion batteries; Nanocomposites; Nanoparticles; Organic chemistry; Rechargeable batteries; Silicon; Structural hierarchy
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/C7RA01877K

High-capacity silicon-based anode materials with high conductivity to promote electron/ion transfer and excellent elasticity to alleviate volume expansion during repeated lithiation/delithiation process are highly desirable for next-generation lithium-ion batteries. Herein, we developed a facile in situ synthesis method based on chemical vapor deposition to fabricate Si-based nanocomposites integrated with interlinked graphene (Gra) and carbon nanotube (CNT). With melt-assembly nanosized Cu as the catalyst, hierarchical three-dimensional conductive Gra/CNT networks were in situ grown onto Si nanoparticles (SNPs) to achieve the Si@Gra@CNT composite. Such a hierarchical structure combines multiple advantages from SNPs with a super high capacity, Gra/CNT framework with continuous electrical conductivity, and void space for tolerance of Si volume expansion. Moreover, the SNPs were conformally encapsulated by few-layer Gra (fGra), which can protect the SNPs from direct exposure to electrolyte, resulting in a stable solid–electrolyte interface. As an anode material for Li-ion battery, the as-prepared Si@Gra@CNT composite exhibited a high initial specific capacity of 1197 mA h g −1 at a current density 2.0 A g −1 and ∼82% capacity retention over 1200 cycles, which was much better than those of Si@Gra and Si@CNT composites. The mechanism for the improved electrochemical performance was further analysed from the aspect of the synergetic effect arising from the construction components.