Deflated Carbon Nanospheres Encapsulating Tin Cores Decorated on Layered 3-D Carbon Structures for Low-Cost Sodium Ion Batteries
Deflated Carbon Nanospheres Encapsulating Tin Cores Decorated on Layered 3-D Carbon Structures for Low-Cost Sodium Ion Batteries
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DOI：
10.1021/sc500543u
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发表时间：
2015-01-01
影响因子：
8.4
通讯作者：
Deng, Da
中科院分区：
文献类型：
--
作者：
Chen, Wei;Deng, Da
成功地合成了包裹金属锡核的新型碳纳米球，并将其修饰在具有壁状结构的三维层状碳上。该复合材料是通过原位碳化和化学气相沉积（CVD）法制备的，可用作钠离子电池负极。SnO 2颗粒原位还原为金属Sn颗粒会由于密度差异而引起颗粒的体积收缩。在CVD条件下，碳纳米球对Sn颗粒的包覆可以形成独特的放气的Sn@C纳米颗粒，其牢固地附着在源自典型农业废弃物的三维碳的表面上。特别有趣的是，所有的碳纳米球都是瘪球形的，这可以在Na插入封闭的Sn中的充电期间为体积膨胀提供额外的空间。所制备的材料片形式的复合材料是现成的电极，其可以直接组装成电池而无需任何进一步的处理，这与制备电极的常规多步骤过程相反。初步结果表明，所制备的放气的Sn@C纳米球在3-D碳上在未来的钠离子电池中的潜在应用。在SIB中，在不同电流下实现了令人印象深刻的高库仑效率。应该注意的是，我们观察到在可逆的Na和Li存储中，在3-D碳上所制备的放气的Sn@C纳米球的电化学性能的显著差异。在钠储存条件下，放气的碳纳米球在循环过程中会破裂，但在锂储存条件下保存良好。这些观察结果表明Li和Na的离子尺寸的重要性及其在充电放电循环期间对电极材料的影响。
Novel deflated carbon nanospheres encapsulating metallic tin cores were successfully synthesized and decorated on 3-D layered carbon with wall-like structures. The composite was synthesized by facile in situ carbonization of walnut shell membranes and chemical vapor deposition (CVD) and can be used as negative electrodes for sodium ion batteries. The in situ reduction of SnO2 particles to metallic Sn partides could induce volumetric shrinkage of the particles due to the density difference. The encapsulation of Sn particles by carbon nanospheres under CVD conditions can form unique deflated Sn@C nanoparticles firmly attached on the surface of the 3-D carbon derived from a typical agricultural waste. Particularly interesting, all the carbon nanospheres are in deflated spherical shape, which could provide extra space for volume expansion during charging in Na insertion into the enclosed Sn. The as-prepared composite in the form of pieces of materials are ready electrodes that can be directly assembled into batteries without any further treatment, in contrast to the conventional multiple-step procedure in making electrodes. Preliminary results demonstrated the potential application of the as-prepared deflated Sn@C nanospheres on 3-D carbon in future sodium ion batteries. Impressive high Coulombic efficiencies were achieved at different currents in SIBs. It should be noted that we observed significant differences in the electrochemical performances of the as-prepared deflated Sn@C nanospheres on 3-D carbon in reversible Na and Li storage. Deflated carbon nanospheres would be broken during cycling in Na storage but were well preserved in Li storage. Those observations suggest the importance of the ionic size of Li and Na and their effects on the electrode materials during charge discharge cycling.