US4548877A — Electrolyte reservoir for carbonate fuel cells

Claim 1

Independent Claim 36 words

An electrode for a carbonate fuel cell comprising an electrode-active material with a plurality of discrete portions of electrolyte dispersed therein, wherein the electrolyte is stored in porous ceramic particles uniformly mixed with said electrode-active material.

Claim 2

Dependent Claim 36 words

An electrode for a carbonate fuel cell comprising an electrode-active material with a plurality of discrete portions of electrolyte dispersed therein, wherein the electrolyte is stored in porous ceramic particles uniformly mixed with said electrode-active material.

Claim 3

Dependent Claim 30 words

The electrode of claim 1, wherein the electrode-active material is present in the range of from about 65 to about 80 percent by volume of the solids of the electrode.

Claim 4

Dependent Claim 23 words

The electrode of claim 1, wherein said electrode is in the form of a sheet having a thickness between 10 and 250 mils.

Claim 5

Dependent Claim 15 words

The electrode of claim 3, wherein said electrode thickness is less than about 100 mils.

Claim 6

Dependent Claim 63 words

The electrode of claim 1, wherein said electrolyte is an alkali metal carbonate is selected from the binary mixtures of Li 2 CO 3 --K 2 CO 3 ; Li 2 Co 3 --Na 2 CO 3 ; Na 2 CO 3 --K 2 CO 3 or the tertiary mixture Li 2 CO 3 --Na 2 CO 3 --K 2 CO 3 .

Claim 7

Dependent Claim 27 words

The electrode of claim 1, wherein the pore size of said porous ceramic particles is in the range of from about 1 micron to about 3 microns.

Claim 8

Dependent Claim 20 words

The electrode of claim 1, wherein the ceramic particles are selected from lithium aluminate, α-alumina, strontium titanate and mixtures thereof.

Claim 9

Dependent Claim 16 words

The electrode of claim 7, wherein the ceramic is plated with nickel, copper or mixtures thereof.

Claim 10

Dependent Claim 60 words

An electrode for a carbonate fuel cell comprising a substantially uniform mixture of an electrode-active powder and porous ceramic particles suitable for a carbonate fuel cell shaped to form an electrode, said porous ceramic particles having pores in the range of from about 1 micron to about 3 microns, and a carbonate electrolyte in the pores of said ceramic particles.

Claim 11

Dependent Claim 60 words

An electrode for a carbonate fuel cell comprising a substantially uniform mixture of an electrode-active powder and porous ceramic particles suitable for a carbonate fuel cell shaped to form an electrode, said porous ceramic particles having pores in the range of from about 1 micron to about 3 microns, and a carbonate electrolyte in the pores of said ceramic particles.

Claim 12

Dependent Claim 43 words

The electrode of claim 9, wherein said electrode-active powder has mean diameters in the range of from about 4 microns to about 9 microns and is selected from the class consisting of nickel, copper, ceramic encapsulated with nickel or copper and mixtures thereof.

Claim 13

Dependent Claim 33 words

The electrode of claim 10, wherein said electrode-active powder is present in the range of from about 50 percent by volume to about 80 percent by volume of the solids of the electrode.

Claim 14

Dependent Claim 32 words

The electrode of claim 9, wherein said ceramic particles are substantially spherical having mean diameters in the range of from about 30 mils to about 60 mils and are agglomerated ceramic powders.

Claim 15

Dependent Claim 30 words

The electrode of claim 12 wherein said electrolyte is in the form of a sheet having a thickness in the range of from about 10 mils to about 60 mils.

Claim 16

Dependent Claim 53 words

A carbonate fuel cell including a porous electrode and a porous electrolyte matrix, said porous electrode having reservoir pores containing discrete quantities of electrolyte therein and bulk pores in said electrode, said bulk pores being larger than said reservoir pores, said pores in said porous electrolyte matrix being smaller than said reservoir pores.

Claim 17

Dependent Claim 53 words

A carbonate fuel cell including a porous electrode and a porous electrolyte matrix, said porous electrode having reservoir pores containing discrete quantities of electrolyte therein and bulk pores in said electrode, said bulk pores being larger than said reservoir pores, said pores in said porous electrolyte matrix being smaller than said reservoir pores.

Claim 18

Independent Claim 118 words

A method of making an electrode for a carbonate fuel cell comprising forming a ceramic powder of about 1 micron mean diameter suitable for use in a carbonate fuel cell into porous particles having mean diameters not less than about 30 mils, the porous particles having pores with mean diameters in the range of from about 1 to about 3 microns, mixing the porous particles with a powder electrode-active material with mean diameters in the range of from about 4 to about 9 microns to form a homogenous mixture, sintering the mixture under a protective atmosphere for a time sufficient to form a rigid matrix, and introducing a carbonate electrolyte into said matrix preferentially into the porous particles.

Claim 19

Independent Claim 118 words

A method of making an electrode for a carbonate fuel cell comprising forming a ceramic powder of about 1 micron mean diameter suitable for use in a carbonate fuel cell into porous particles having mean diameters not less than about 30 mils, the porous particles having pores with mean diameters in the range of from about 1 to about 3 microns, mixing the porous particles with a powder electrode-active material with mean diameters in the range of from about 4 to about 9 microns to form a homogenous mixture, sintering the mixture under a protective atmosphere for a time sufficient to form a rigid matrix, and introducing a carbonate electrolyte into said matrix preferentially into the porous particles.

Claim 20

Dependent Claim 20 words

The method of claim 15, wherein the ceramic powder is selected from lithium aluminate, α-alumina, strontium titanate and mixtures thereof.

Claim 21

Dependent Claim 35 words

The method of claim 15, wherein the electrode-active material contains nickel or copper and is present in the range of from about 65 to about 80 percent by volume of the solids of the electrode.

Claim 22

Dependent Claim 58 words

The method of claim 15, wherein the electrolyte is selected from the binary mixtures of Li 2 CO 3 --K 2 CO 3 ; Li 2 CO 3 --Na 2 CO 3 ; Na 2 CO 3 --K 2 CO 3 or the tertiary mixture Li 2 CO 3 --Na 2 CO 3 --K 2 CO 3 .

Claim 23

Dependent Claim 47 words

The method of claim 15, wherein the mixture is formed into a thin sheet and sintered at a temperature of about 1000° C. for a period of about 1 hour, the sheet having a thickness in the range of from about 10 mils to about 100 mils.

Claim 24

Dependent Claim 41 words

The method of claim 15, wherein the carbonate electrolyte is introduced by loading solid electrolyte onto the rigid matrix and heating to a temperature slightly higher than the liquidus temperature of the electrolyte until the electrolyte melts into the porous particles.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1988-10-21	1989-04-22	1989-10-22	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1992-10-21	1993-04-22	1993-10-22	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1996-10-21	1997-04-22	1997-10-22	$7700.00	Window Closed / Lapsed

Electrolyte reservoir for carbonate fuel cells

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