| 摘要 |
The present invention relates to a lithium secondary battery comprising: a negative electrode to which a silicon-carbon composite is applied, the expansion of the volume of the silicon-carbon composite when a lithium ion is inserted being low and the silicon-carbon composite having excellent ion conductivity and electric conductivity to consistently maintain a high capacity; and an electrolyte for improving the electrochemical properties of the negative electrode. The lithium secondary battery of the present invention uses the silicon-carbon composite for a negative electrode active material so as to achieve the complexation of silicon and carbon fibers, and involves the coating of the surface of silicon particles with amorphous silica so as to reduce the expansion of volume when a lithium ion is inserted. The lithium secondary battery of the present invention has excellent ion conductivity and electric conductivity to consistently maintain high capacity. Further, the lithium secondary battery of the present invention uses an electrolyte to which additives such as FEC, VEC, VC, EC, DFEC, t-butylbenzene and t-pentylbenzene are added, thus improving electrochemical properties of the silicon-carbon composite such as coulombic efficiency, capacity, and rate control properties. |
