In recent years,as the integrated circuit (IC) technologies and Micro/Nano-Electro-Mechanical System (M/NEMS) develop rapidly,more and more micro/nano devices are fabricated or commercialized.1,2 But the lagged pace of the battery miniaturization hinders the further scaling down or long lasting life of those devices.Moreover,it becomes even un-conceivable to integrate the power supply system within the device structure when reducing the sizes of all kinds of micro devices into nano scale.Among various energy storage systems,the rechargeable lithium ion battery (LIB) is a predominant power source due to its relatively high energy density and long life time.3 Traditional thin film rechargeable LIBs designed in two dimensional (2D) geometries need large footprint areas to achieve large capacities,resulting in a compromise between the energy and power densities.4 Therefore,many researchers have begun to turn eyes on the 3D rechargeable LIBs with the higher power and energy densities in a small footprint area.In this work,the periodic 3D hexagonal Si/SnO2 NR arrays in a large area were fabricated using the modified nanosphere lithography (NSL) method combined with the inductive couple plasma (ICP) dry etching technology.3D hexagonal Si/SnO2 core-shell nanocomposites in a "bottle" shape with superior homogeneity and verticality were fabricated by choosing suitable polystyrene (PS) template and optimizing the ICP etching time and cycles.The performance and mechanism during the lithium ion insertion/de-insertion in the Si/SnO2 NR arrays were studied.The results indicate that the 3D Si/SnO2 composite anode in nanorod arrays exhibits significantly improved mechanical stability and cycleability compared to the Si NRs or planar Si.The successful fabrication of the 3D Si/SnO2 NR arrays on Si substrates and their practical application in LIBs offer a feasible option to integrate the micro-power source into the IC systems,M/NEMS or other electronic devices.