Carbon electrodes and electrochemical capacitors
AssigneeLithdyne LLC
InventorsW. Novis Smith, Joel R. McCloskey, James J. Gormley
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Abstract
Carbon electrodes for a capacitor having conditioned carbon elements in combination with a high concentration of an electrolyte tetrafluoroborate salt and a non-aqueous aprotic solvent to provide an operational voltage up to 4.5V and capacitors used with the carbon electrodes.
Claims13
In a non-aqueous electrochemical capacitor having sealed carbon electrodes, the improvement which comprises at least one carbon electrode comprising;
- a) a metal collector on the top and bottom surfaces;
- b) optionally a first conductive carbon layer on each of the top and bottom interior surfaces of the collectors;
- c) a porous second conductive carbon layer on each of said first conductive carbon layers, said second conductive carbon layers being substantially free of oxygen and heteroatom containing functional groups and being degassed,
- d) a porous inert separator between said second conductive carbon layers;
- and
- e) an electrolyte having a quaternary ammonium tetrafluoroborate salt concentration of at least 1.5M in an aprotic solvent.
In a capacitor having a carbon electrode the improvement which comprises that said carbon in the electrode was heat treated to remove oxygen and sulfur functional groups and silica by heating at a temperature between 850 and 1300° C., formed into at least one disc that is used in the electrode which is placed in said capacitor and which undergoes a burn-in with a voltage ramp-up to 4.4 and degassed.
Dependencies are inferred from the claim text.