PURPOSE: To improve the discharge duration performance of a dry battery by forming a positive electrode using a positive electrode active substance obtainable from processes where the specified powder of chemically synthesized manganese dioxide is mixed with carbon fiber manufactured through a gaseous phase synthesizing method, and this mixture is compression molded and crushed.
CONSTITUTION: Manganese oxide obtained by calcining manganese sulfate is treated by use of sulfuric acid, nitric acid, hydrochloric acid and the mixed acid thereof, thereby providing chemically synthesized manganese dioxide (CMD) mainly composed of γ type. Then, carbon fiber is added to the powder of the CMD by an amount between 0.1wt% and 2wt% and, then, the mixture of the CMD and the carbon fiber is molded and crushed. In addition, an alkaline electrolyte or the like is added to the crushed mixture and compression molded into a hollow cylindrical form for use as a positive electrode 2. Accordingly, each CMD particle is enclosed with the carbon fiber, and a utilization factor for discharge is remarkably improved. The positive electrode 2 is housed in a metal can 1 as a terminal in common, the hollow section of the electrode 2 is filled with a gel type negative electrode mix 4 via a separator 3, and a brass negative electrode rod 5 is inserted. An insulation gasket 7 is fitted between the can 1 and a metal sealing plate 6, and the edge of the can 1 is bent inward, thereby sealing the can 1.
KOBAYASHI KAZUNARI
OGINO AKIHIRO
KANEKO HIROSHI
CHIBA NOBUAKI
