Cathode including a non fluorinated linear chain polymer as the binder, method of making the cathode, and lithium electrochemical cell containing the cathode

Existing technology for the fabrication of cathodes for use in lithium primary and secondary cells utilizes Teflon as the binding material. Teflon or polytetrafluoroethylene is expensive though inert, and its use results in cathode structures of poor mechanical stability. These problems do not easily lend themselves to the large scale production of cathodes in manufacturing. This patent application pertains to a cathode suitable for use in a lithium electrochemical cell. It is made from a mixture of active cathode material, carbon, and non fluorinated linear chain polymer by a method including the steps of: (1) dissolving the non fluorinated linear chain polymer in a non polar solvent at a temperature near the melting point of the polymer; (2) adding the active cathode material and carbon and evaporating the solvent; and (3) grinding the dried mixture into a fine powder and making it into a cathode by pressing the powdered mixture onto both sides of an expanded metal screen and then cutting to the desired dimensions. The cathode can be combined with lithium as the anode and a solution of 0.8 mol 3/dm LiAlCl4 in a mixed organic solvent of 24 mass percent 4-butyrolactone in 1, 2 dimethoxyethane as the electrolyte to provide a mechnically stable, relatively inexpensive lithium electrochemical cell having good cell performance.