Abstract: Disclosed are a silicon nanostructured material with theoretical storage capacity of energy resulting from electrochemical reaction with lithium improved more than 10 times as compared to the existing graphite material and having superior output characteristics, an electrode including the same, and a secondary battery and an electrochemical capacitor including the electrode as a negative electrode. The physical stability of the electrode active material is improved and an electrode with high performance can be obtained. Since more energy can be stored as compared to the graphite material of the same thickness and high-output performance can be achieved through the nanostructure, energy density can be remarkably improved as compared to the existing lithium-ion battery by about 2 times. An asymmetric lithium-ion secondary battery including the electrode active material is applicable to storage of renewable energy, ubiquitous power source, power supply for machinery and vehicles, or the like.