Solvothermal-Assisted Hybridization between Reduced Graphene Oxide and Lithium Metal Oxides: A Facile Route to Graphene-Based Composite Materials

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• 作者：Song Yi Han ; In Young Kim ; Kyung Yeon Jo ; Seong-Ju Hwang
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：April 5, 2012
• 年：2012
• 卷：116
• 期：13
• 页码：7269-7279
• 全文大小：606K
• 年卷期：v.116,no.13(April 5, 2012)
• ISSN：1932-7455

文摘

Hybridization between lithium metal oxide and reduced graphene oxide, or RGO, can be achieved by the solvothermal treatment of the water/ethanol-based suspension of graphite oxide, or GO, nanosheets containing powdery lithium metal oxide. The solvothermal treatment for the mixture suspension of GO and Li₄Ti₅O₁₂ gives rise not only to the reduction of GO to RGO but also to the attachment of the Li₄Ti₅O₁₂ particles to the flat surface of RGO 2D nanosheets. The crystal structure and crystal morphology of the Li₄Ti₅O₁₂ particles remain intact after the composite formation with the RGO nanosheets. The formation of chemical bonds and internal electron transfer between the RGO and Li₄Ti₅O₁₂ components is evidenced by micro-Raman and X-ray photoelectron spectroscopy, showing the weakening of the carbon鈥揷arbon bonds and the formation of carbon鈥搊xygen bonds. In comparison with the pristine Li₄Ti₅O₁₂ material, the Li₄Ti₅O₁₂鈥揜GO nanocomposites display better anode performance with a larger discharge capacity of 175 mAhg^鈥?, underscoring the merit of RGO hybridization in improving the electrode performance of bulk metal oxide. Diffuse reflectance UV鈥搗is and photoluminescence spectroscopic analyses reveal a strong electrical connection between lithium titanate and RGO, which is mainly responsible for the observed improvement of the electrode performance upon the composite formation. In addition to the electrode performance, the photocatalytic activity of the lithium titanate for the generation of photocurrent can be remarkably enhanced by the coupling with RGO, confirming the usefulness of the present synthetic method in optimizing the photoinduced functionality of metal oxides. The solvothermal strategy presented here is also applicable for the synthesis of LiMn₂O₄鈥揜GO nanocomposite showing much superior electrode performance over the pristine LiMn₂O₄. The experimental findings underscore that the present synthetic method can provide a universal way to not only immobilize multicomponent metal oxides on the surface of RGO nanosheets with a strong electrical connection but also improve the electrode and photocatalytic activity of these metal oxides.