Preparation and electrochemical properties of SnO2 nanowires for application in lithium-ion batteries
Preparation and electrochemical properties of SnO2 nanowires for application in lithium-ion batteries
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DOI：
10.1002/anie.200603309
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发表时间：
2007-01-01
影响因子：
16.6
通讯作者：
Liu, Hua-Kun
中科院分区：
文献类型：
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作者：
Park, Min-Sik;Wang, Guo-Xiu;Liu, Hua-Kun
一维（1D）纳米结构材料由于其具有吸引力的电子、光学和热性能，在先进的功能系统和广泛的应用中受到了相当大的关注。[1-2]在锂离子电池科学中，最近的研究集中在纳米级电极材料上，以提高电化学性能。一维纳米结构材料的高表面体积比和优异的表面活性激发了人们对其开发下一代电源的极大兴趣。[3-4]基于氧化锡的材料已被提出作为锂离子电池中具有高能量密度和稳定容量保持的替代阳极材料。[5-7]各种sno2基材料表现出非凡的电化学行为，在纳米尺度下，由Li2O形成引起的初始不可逆容量和由体积变化引起的突然容量衰减可以有效地减少。[8-10]从这个角度来看，SnO2纳米线也可以被认为是一种有前途的阳极材料，因为纳米线结构具有独特的电子和结构特性。此外，采用热蒸发法可以很容易地合成纳米线。然而，以目前的形式，这种制造SnO2纳米线的方法有几个局限性：它不适合大规模生产，因为需要很高的合成温度，并且在消除可能作为杂质或缺陷的金属催化剂方面存在困难。这会导致电化学反应过程中可逆容量损失或循环性能差。[11,12] SnO2纳米线作为锂离子电池负极材料的关键问题是如何避免催化剂的恶化效应以及如何提高产量。在此，我们报告了自催化生长的SnO2纳米线的制备和电化学性能，以确定其作为锂离子电池负极材料的潜力。利用球磨蒸发材料，采用热蒸发与自催化生长相结合的方法合成了SnO2纳米线，提高了低温下的产量，避免了传统催化剂对电化学性能的不良影响。自催化生长的SnO2纳米线与au辅助生长的SnO2粉末和SnO2纳米线相比，具有更高的初始库仑效率和更好的循环保留率采用SnO和Sn粉的球磨混合物作为蒸发源的自催化生长方法，适合获得高纯度的SnO2纳米线。在Si衬底上沉积的产物几乎含有100%形成的SnO2纳米线。扫描电子显微镜（SEM）清晰地显示了随机排列的SnO2纳米线的总体视图，直径为200-500 nm，长度延伸至数十微米（图1a）。利用能量色散x射线（EDX）对纳米线尖端的Sn液滴进行了观察和确认。
One-dimensional (1D) nanostructured materials have received considerable attention for advanced functional systems as well as extensive applications owing to their attractive electronic, optical, and thermal properties.[1–2] In lithium-ion-battery science, recent research has focused on nanoscale electrode materials to improve electrochemical performance. The high surface-to-volume ratio and excellent surface activities of 1D nanostructured materials have stimulated great interest in their development for the next generation of power sources.[3–4] Materials based on tin oxide have been proposed as alternative anode materials with high-energy densities and stable capacity retention in lithium-ion batteries.[5–7] Various SnO2-based materials have displayed extraordinary electrochemical behavior such that the initial irreversible capacity induced by Li2O formation and the abrupt capacity fading caused by volume variation could be effectively reduced when in nanoscale form.[8–10] From this point of view, SnO2 nanowires can also be suggested as a promising anode material because the nanowire structure is of special interest with predictions of unique electronic and structural properties. Furthermore, the nanowires can be easily synthesized by a thermal evaporation method. However, in its current form, this method of manufacture of SnO2 nanowires has several limitations: it is inappropriate for mass production as high synthesis temperatures are required and there are difficulties in the elimination of metal catalysts that could act as impurities or defects. This results in reversible capacity loss or poor cyclic performance during electrochemical reactions.[11, 12] The critical issues relating to SnO2 nanowires as anode materials for lithium-ion batteries are how to avoid the deteriorative effects of catalysts and how to increase production.Herein, we report on the preparation and electrochemical performance of self-catalysis-grown SnO2 nanowires to determine their potential use as an anode material for lithium-ion batteries. SnO2 nanowires have been synthesized by thermal evaporation combined with a self-catalyzed growth procedure by using a ball-milled evaporation material to increase production at lower temperature and prevent the undesirable effects of conventional catalysts on electrochemical performance. The self-catalysis-grown SnO2 nanowires show higher initial coulombic efficiency and an improved cyclic retention compared with those of SnO2 powder and SnO2 nanowires produced by Au-assisted growth.[11] The self-catalysis growth method, which uses a ball-milled mixture of SnO and Sn powder as an evaporation source, is appropriate for obtaining SnO2 nanowires with high purity. The deposited products on the Si substrates contain almost 100% of the SnO2 nanowires formed. Observation with scanning electron microscopy (SEM) clearly shows a general view of randomly aligned SnO2 nanowires with diameters of 200–500 nm and lengths extending to several tens of micrometers (Figure 1a). Sn droplets at the tips of nanowires were observed and confirmed by energy dispersive X-ray (EDX)