Supercapacitor and a method of manufacturing such a supercapacitor

Abstract

An electric double layer capacitor including at least one pair of polarizable electrodes connected to current collectors, a separator made of ion-permeable but electron-insulating material interposed between the electrodes in each pair of electrodes, and a liquid electrolyte. According to the invention the electrodes include a layer of carbon particles having a narrow distribution of nanopores therein, the pore sizes of the nanopores being adapted to fit the ion sizes of the electrolyte. The invention also relates to a method of manufacturing such a supercapacitor.

What is claimed:  
     
         1 . A method of manufacturing an electrode for an electric double layer capacitor, characterized by mixing a mixture comprising carbon particles having nanopores with a predetermined size, at least a primary binder and a secondary binder and a solvent, extruding the mixture, rolling the extruded mixture into sheet shape and thereafter attaching the formed electrode sheet to a conductive foil or mesh.  
     
     
         2 . The method according to  claim 1 , characterized in that the mixing step comprises dry mixing, wet mixing, muller mixing and grinding.  
     
     
         3 . A method of manufacturing an electrode for an electric double layer capacitor, characterized by mixing a mixture comprising carbon particles having nanopores with a predetermined size, at least a primary binder and a secondary binder and a solvent, roll mixing the mixture, rolling the mixture into sheet shape and thereafter attaching the formed electrode sheet to a conductive foil or mesh.  
     
     
         4 . The method according to  claim 3 , characterized in that the mixing step comprises dry mixing and wet mixing.  
     
     
         5 . The method according to  claim 1 , characterized in that the step of rolling the mixture into sheet shape is performed by roll compaction.  
     
     
         6 . The method according to  claim 5 , characterized by removing the solvent and the secondary binder from the formed electrode sheet by heat treatment, said secondary binder being removable from the formed electrode sheet at a temperature below the decomposition temperature of the first binder.  
     
     
         7 . A method of manufacturing an electrode for an electric double layer capacitor, characterized by mixing a mixture comprising carbon particles having nanopores with a predetermined size, a binder and a solvent to a slurry and tape casting the slurry directly onto a conductive foil.