Silicon (Si) nanowires (NWs) grown on stainless-steel substrates by Cu-catalysed Chemical Vapour Deposition (CVD) have been prepared to be used as anodes in lithium-ion batteries. The use of NWs can overcome the problems related to the Si volume changes occurring during lithium alloying by reducing stress relaxation and preventing material fragmentation. Moreover, since the SiNWs are grown directly on the substrate, which also acts as a current collector, an excellent electrical contact is generated between the two materials without the necessity to use additional binders or conducting additives. The electrochemical performance of the SiNWs was tested in cells using lithium metal as the anode. A large irreversible capacity was observed during the first cycle and, to a lesser extent, during the second cycle. All the subsequent cycles showed good reversibility even if the coulombic efficiency did not exceed 95%, suggesting the formation of an unstable SEI film and a continuous decomposition of the electrolyte on the silicon surface. The absence of a stable SEI film was assumed responsible for a linear capacity fade observed upon cycling. On the other hand, the electrochemical characterization performed at different values of the charging current showed that SiNWs possess an exceptionally high rate capability.

中文翻译：

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铜催化的硅纳米线作为锂离子电池阳极的电化学表征

已经准备了通过Cu催化化学气相沉积（CVD）在不锈钢基板上生长的硅（Si）纳米线（NW），用作锂离子电池的阳极。通过减少应力松弛并防止材料碎裂，使用NW可以克服与锂合金化过程中发生的Si体积变化有关的问题。而且，由于SiNW直接在还用作集电器的基底上生长，因此在两种材料之间产生了优异的电接触，而无需使用额外的粘合剂或导电添加剂。在使用锂金属作为阳极的电池中测试了SiNW的电化学性能。在第一个循环中观察到较大的不可逆容量，在第二个循环中观察到较小的程度。即使库仑效率不超过95％，所有随后的循环仍显示出良好的可逆性，这表明形成了不稳定的SEI膜和电解质在硅表面上连续分解。假定没有稳定的SEI膜会导致循环时观察到的线性容量衰减。另一方面，在不同充电电流值下进行的电化学表征表明，SiNW具有极高的倍率能力。