TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Properties: The air cathode has a thickness of 0.8-2.0 mm, and a density of 1-30 g/cm3. Preferred Process: The heat drying process is carried out in a way that the water content of the mixture after drying is below 4%. When more than two sintered diffusion layers are to be produced, the procedures for carrying out the step of coating with the carbon powder and sintering process are repeated until the desired multiple-layered structure is obtained, and then the thickness of the sintered diffusion layer is adjusted using the roller press machine. When more than two sintered activation layers are to be produced, the procedures for carrying out the step of coating with the size and sintering process are repeated until the desired multiple-layered structure is obtained for making the air cathode having the laminating shaped multiple layer sintering structure. The sintering process in the first mixing step is carried out in a way that the base material carrying the hydrophobic carbon powder is heated at 300-350degreesC for 20-40 minutes. The sintering process in the second mixing step is carried out in a way that the base material carrying the sintered diffusion layer and the sintered activation layer is heated at 350-400degreesC for 20-40 minutes.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Component: The catalyst carried by the sintered activation layer is oxide or salt of transition metal of iron, cobalt, nickel and manganese.    TECHNOLOGY FOCUS - METALLURGY - Preferred Material: The base material is made of metal net including metal wire net and metal foam net. It is preferably made of nickel net.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Material: Each sintered diffusion layer is made of acetylene-reduced carbon black or coking carbon black by sintering process. The sintered activation layer is made of acetylene-reduced carbon black, coking carbon black, nanometer carbon tube or nanometer carbon horn.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Component: The catalyst carried by the sintered activation layer is oxide or salt of transition metal of iron, cobalt, nickel and manganese.