Vertically ordered Ni₃Si₂/Si nanorod arrays as anode materials for high-performance Li-ion batteries

In this paper, we have reported a novel hierarchical nanostructure made of vertically ordered Ni₃Si₂/Si nanorod arrays to moderate the notorious pulverization and capacity decay usually occurring in the silicon used as the anode materials in Li-ion batteries. During the lithiation and delithiation process, the amorphous Si (a-Si) layer acts as an active material and participates in the processes, whereas the Ni₃Si₂ nanorod arrays work as a mechanically stable supporter and fast charge transport pathway. In addition, they can afford sufficient interspace for expansion/contraction upon lithium insertion/extraction. These Ni₃Si₂/Si nanorod arrays anodes exhibit excellent cycling performance at high current rates of 1 C (4.2 A g⁻¹), 2 C (8.4 A g⁻¹), and 4 C (16.8 A g⁻¹), respectively. A high and steady discharge capacity of over 2184 mA h g⁻¹ can be achieved after 50 cycles with a high initial coulombic efficiency of 86.7%. The synthesis approach is simple, efficient and rich-yielding, probably providing a new strategy for the application of silicon-based anode materials with enhanced performance.