中文摘要：

硅是目前已知的理论比容量最高的锂离子电池负极材料,但是循环性能较差。本文通过射频磁控溅射的方法,成功合成出了NiSix/Si/Ge核壳纳米棒阵列,并通过扫描电子显微镜（SEM）和能量色散X射线光谱仪（EDX）对其形貌和成分进行了表征。将原位生长的NiSix/Si/Ge核壳纳米棒阵列直接作为工作电极,组装成纽扣半电池进行电化学和循环性能测试,NiSix/Si/Ge核壳纳米棒阵列的首次放电容量达到了2000mAhg-1左右,首次效率在70%左右,并且在100个循环以后仍保有初始可逆容量的30%以上。相比NiSix/Si纳米棒阵列,NiSix/Si/Ge核壳纳米棒阵列的循环性能明显得到了提升,说明锗的包覆对硅的锂离子电池性能改进起到了非常重要的作用。

英文摘要：

As well-known, silicon possesses the highest capacity （4200 mAhg-1） of all the existing anode materiads at room temperature in addition to Li metal. However, the poor cycling performance of Si-based anodes severely limits the widespread applications in lithium-ion batteries. Herein, we report the synthesis of the arrayed NiSix/Si/Ge nanorods by RF magnetron sputtering to enhance the cycling performance of Si-based anodes. The morphology and composition of the arrayed NiSix/Si/Ge nanorods were characterized by scanning electron microscopy （SEM） and energy dispersive X-ray spectroscopy （EDX）. The as-prepared NiSix/Si/Ge nanorod arrays were directly assembled into the button half-cell as the working electrode, and the electrochemical performance was also evaluated. The arrayed NiSix/Si/Ge nanorods show a first discharge capacity of about 2000 mAhg-1, the initial Coulombic efficiency about 70 %, and retain more than 30 % of the initial reversible discharge capacity after 100 cycles. Compared with NiSix/Si nanorod arrays, the cycle performance of the NiSix/Si/Ge core-shell nanorod arrays has been substantially improved. This result indicates that the coating of germanium on silicon plays a key role in enhancing the cycling performance of lithium-ion battery.