Electrochemical capacitor
AssigneesWisconsin Alumni Research Foundation, Lockheed Martin Idaho Technologies Company
InventorsMarc A. Anderson, Kuo-Chuan Liu, Charles M. Mohr
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Abstract
An inexpensive porous metal oxide material having high surface area, good conductivity and high specific capacitance is advantageously used in an electrochemical capacitor. The materials are formed in a sol-gel process which affords control over the properties of the resultant metal oxide materials.
Claims21
An electrochemical capacitor comprising an anode and a cathode, the anode and the cathode comprising:
- an electrode substrate;
- a porous coating on the substrate, the coating comprising a metal oxide and having a surface area of greater than 30 m.sup.2 /g, a porosity in the range of 10 to 80%, a mean grain size between 2 and 100 nm, and a mean pore size of between 0.5 and 20 nm;
- and
- an electrolyte in contact with the coating,
- wherein the metal oxide comprises an anion and a cation in a non-stoichiometric ratio.
An electrochemical capacitor formed according to a process comprising the steps of:
- coating onto a pair of electrode substrates a sol comprising metal oxide colloidal particles of between 2 and 100 nm in diameter;
- drying the sol onto the substrates to form a xerogel;
- firing the xerogel in an atmosphere at a temperature that does not destroy the porous microstructure of the xerogel, for a time sufficient to yield on the substrates a porous metal oxide material that comprises an anion and a cation in a non-stoichiometric ratio, the material having a surface area of greater than 30 m.sup.2 /g, a porosity in the range of 10 to 80%, a mean grain size between 2 and 100 nm, and a mean pore size of between 0.5 and 20 nm, to form a pair of electrodes;
- and
- immersing the electrodes into an electrolyte.
An electrode comprising:
- an electrode substrate;
- a porous coating on the substrate, the coating comprising a metal oxide that comprises an anion and a cation in a non-stoichiometric ratio, the coating having a surface area of greater than 50 m.sup.2 /g, a porosity in the range of 10 to 80%, and a mean pore size of between 0.5 and 20 nm.
An electrochemical capacitor consisting of:
- a pair of electrode substrates;
- a porous coating on the substrates, the coating comprising a metal oxide that comprises an anion and a cation in a non-stoichiometric ratio, the coating having a surface area of greater than 30 m.sup.2 /g, a porosity in the range of 10 to 80%, a mean grain size between 2 and 100 nm, and a mean pore size of between 0.5 and 20 nm;
- and
- an electrolyte in contact with the coating.
Dependencies are inferred from the claim text.