In situ chemical synthesis of SnO 2 /reduced graphene oxide nanocomposites as anode materials for lithium-ion batteries
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npan Xu, Yang Ni, and Hongya Geng Institute of Nanochemistry and Nanobiology, School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, People’s Republic of China
Guanghong Zheng and Bin Dongb) College of Environmental Science and Engineering, Tongji University, Shanghai 200092, People’s Republic of China
Zheng Jiaoa) Institute of Nanochemistry and Nanobiology, School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, People’s Republic of China (Received 20 November 2013; accepted 27 January 2014)
In the work, an in situ chemical synthesis approach has been developed to fabricate SnO2/reduced graphene oxide nanocomposites in ethanol solution. X-ray diffraction, x-ray photoelectron, Fourier transform infrared and Raman spectrum revealed the formation of SnO2/reduced graphene oxide nanocomposites. Scanning electron microscopy and transmission electron microscopy showed that SnO2 nanoparticles had a crystal size of about 3–4 nm and homogeneously distributed on reduced graphene oxide matrix. The electrochemical performances of the SnO2/reduced graphene oxide nanocomposites as anode materials were measured by the galvanostatic charge/discharge cycling. The results indicated that as-synthesized SnO2/reduced graphene oxide nanocomposites had a reversible lithium storage capacity of 1051 mAh/g and an enhanced cyclability, which can be attributed to increased electrode conductivity and buffer effect to volume change in the presence of a percolated reduced graphene oxide network embedded into the metal oxide electrodes.
I. INTRODUCTION
Li-ion batteries, as power sources for mobile communication devices, electrical/hybrid vehicles, and portable electronic devices, have been receiving great attentions due to their high electromotive force and high energy density. Currently, graphite is a common anode electrode material because of its reversibly charged and discharged capability under intercalation potentials.1,2 Thus, with the increasing demand for batteries with higher energy density, the practical application of graphite is hindered due to its limited theoretical capacity (372 mAh/g). Therefore, extensive works are being focused on exploring new electrode materials.3–6 Tin oxide (SnO2) is a good substitute for the graphitic anode in Li-ion batteries because its high theoretical Li1 storage capacity of 782 mAh/g, which is nearly 3 times that of graphite. However, similar to other lithium reactive electrode materials, very large
Address all correspondence to these authors. a) e-mail: [email protected] b) e-mail: [email protected] DOI: 10.1557/jmr.2014.37 J. Mater. Res., Vol. 29, No. 5, Mar 14, 2014
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volume change of about 300% is produced during charge/ discharge process of SnO2, which causes cracking and crumbling of electrode, leading to electrical disconnection from current collectors.7–10 Consequently, SnO2 electrode suffers from rapid fading of capacity and its fading rate is 5–10 times that of graph
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