However, graphite has an inherent limitation with a theoretical gravimetric capacity estimated at 370 mAh/g. For the purpose of improving the energy density of batteries, scientists have made great efforts to explore alternative anode materials with higher capacity.
Lithium ion batteries using the lithium transition metal oxide cathode and graphite anode have been the power sources for various mobile communication devices, portable electronic devices, and electric/hybrid vehicles.
oxidation–reduction reaction between graphene oxide and SnCl2•2H2O. The SnO2/graphene composite showed a superior rate capability and
cycling performance.
There are two electrochemical processes in the SnO2-based lithium ion batteries:
As the reaction (2) demonstrates, a volume change of 200–300% occurs during lithiation/delithiation process between Sn and Li4.4Sn. This reaction can generate a large internal stress, leading to cracking of electrode, loss of electrical contact, large initial irreversible capacity, and eventually quick fading of capacity.
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To overcome the internal stress problem, great attention has
been paid to nano-structured SnO2 and SnO2/carbon composite electrodes. Graphene, a monolayer of graphite, exhibits a number of intriguing unique properties such as high surface area of over
2600m2/g, large surface-to-volume ratio, high room temperature
(RT) carrier mobility, conductance quantization
Therefore, graphene has been regarded as an ideal carbon nanostructure which can be used to design high performance SnO2/carbon composite electrodes.
capacity could remain 570 mAh/g after 30 cycles at a current density of 50 mA/g.
Yao et al. [22] synthesized SnO2/graphene composite by direct oxidation of a Sn– graphene composite (which were prepared by coreduction of graphene oxide and Sn2+ with NaBH4) at 120 C in atmosphere. The obtained SnO2/graphene composite had a capacity of 765 mAh/g at the first cycle at a current density of 55 mA/g. Besides, Wang et al. prepared SnO2-graphene composite using a ternary self-assembly
专业英文文献选读
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A Stability electrode for lithium ion batteries
Carbon Volume 49, Issue 1, January 2011：133–139
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Introduction
of SnO2/graphene composite in these reports. In addition, more efforts are needed to improve the cycling performance of the composite.
In this paper, we prepared a SnO2/graphene composite through an
approach. The composite delivered a specific capacity of 625 mAh/g after 10 cycles at
a current density of 0.01 A/g.
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However, it is a pity that there are no studies about high rate performance
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As a large band gap semiconductor, SnO2 has attracted a lot of attention
due to its relatively high theoretical reversible capacity (790 mAh/g), which is more than twice that of the currently used graphite.
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Up to date, there have been a few reports about the preparation of SnO2/graphene composite.
Paek et al. [2] synthesized a SnO2/graphene composite with three-dimensionally delaminated flexible structure by mechanical mixing SnO2 nanoparticles with graphene nanosheets. The as-prepared SnO2/graphene electrode material exhibited an enhanced cyclic performance and lithium storage capacity. As claimed, the charge
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