| 摘要 |
PURPOSE:To stabilize discharge capacity at all times regardless of a cycle progress by fixing a carbon fine powder having the predetermined mean grain size ratio against the MnO2 grain of an active material to the surface of the MnO2 grain for forming a complex grain powder, and using the material so formed as a positive electrode. CONSTITUTION:For the MnO2 grain of an active material, a carbon material fine powder having a mean grain size ratio of 10<-1> to 10<-5> is fixed onto the MnO2 grain surface, thereby forming a positive electrode having a complex grain powder. Furthermore, a granulated graphite powder or an activated carbon powder as a conductive material is contained in the aforesaid positive electrode, in addition to the carbon material fine powder contained in the complex grain powder. Moreover, the carbon material fine powder in the aforesaid complex grain is carbon black or fibrous graphite. When the carbon black is used, the amount thereof fixed to the surface of MnO2 is taken at 2 to 5wt% for MnO2. Also, when the fibrous graphite is used, the amount thereof fixed to the surface of MnO2 is taken at 1 to 3wt.% for MnO2. In addition, the granulated graphite powder or the activated carbon powder is taken at 2 to 5wt.% for MnO2. |
