| 摘要 |
<P>PROBLEM TO BE SOLVED: To remarkably improve low initial efficiency which is a defect without obstructing initial charge capacity characterizing a lithium secondary battery using an SiO negative electrode and hinder drop in cycle characteristics caused by increasing the thickness of the SiO layer. <P>SOLUTION: A thin film of SiO of a negative active material is formed on the surface of a current collector by vacuum deposition, preferably by an ion plating method. An Si-SiO mixture powder sintering target containing Si powder of 5-30 wt.% is used as a film forming target. The thickness of the SiO thin film is made 5 μm or more. The surface roughness (Rz) of the current collector is made 5.0 or more in maximum height of irregularities. After the thin film is formed, it is heat-treated in the nonoxidative atmosphere at 650-850°C. <P>COPYRIGHT: (C)2007,JPO&INPIT |
