method for the manufacture of a positive electrode in a galvanic cell and every trode containing such a galvanic cell.

摘要

1,249,044. Cathode for electric cell. AMERICAN CYANAMID CO. 31 Oct., 1969 [5 Dec., 1968], No. 53586/69. Heading H1B. A cathode for an electric cell comprises a porous sheet comprising (A) a web of water-laid intermeshed fibres and electroconductive cathode-active particles, said particles forming an electroconductive network in said web and constituting at least 25% thereof and (B) incorporated with the web an electrically conductive scrim core of metal grid sheet material. In a particular embodiment, a slurry comprising acetylene black, as cathode-active material, asbestos fibres, polytetrafluoroethylene emulsion as a binder and water is first mixed with acetone and vigorously agitated to coagulate the emulsion and then filtered through a copper screen covered with a polytetrafluoroethylene screen to form a mat of fibres and active material. This is dried by passing air through it and then a scrim core sheet of expanded aluminium is placed on it before another mat of fibres and active material of the same composition is similarly formed on top. A further sheet of polytetrafluoroethylene is placed on top of the mat and the whole assembly is removed from the copper screen, wrapped in blotting paper, calendered to remove water, and cut into strips. Finally, a terminal tab is attached to the aluminium sheet. To form a cell, a lithium foil anode between two paper separators is placed against the cathode so that its terminal tab is at the opposite end of the pack. The pack is coiled with the cathode tab in the middle and placed in a steel can, the anode tab connected to the can, a metal cover having a valve in it is attached to the cathode tab and then insulatingly sealed to the can. The can is evacuated, purged with SO 2 , filled with an electrolyte comprising acetonitrile, propylene carbonate, LiBr and SO 2 and sealed. In another embodiment, the mat of fibres also contains aluminium flake.