CA1148610A - Catalyst surface for the chromous/chromic redox couple - Google Patents
Catalyst surface for the chromous/chromic redox coupleInfo
- Publication number
- CA1148610A CA1148610A CA000340611A CA340611A CA1148610A CA 1148610 A CA1148610 A CA 1148610A CA 000340611 A CA000340611 A CA 000340611A CA 340611 A CA340611 A CA 340611A CA 1148610 A CA1148610 A CA 1148610A
- Authority
- CA
- Canada
- Prior art keywords
- electrode
- anode
- fluid
- chamber
- cathode
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
- Y02E60/50—Fuel cells
Abstract
ABSTRACT OF THE DISCLOSURE
An electrical storage cell of the reduction oxidation (REDOX) type is divided into anode and cathode compartments by a membrane, each compartment having a circulating fluid containing an ion couple for producing an electric potential at respective solid inert electrodes disposed therein. The anode electrode is plated with one layer of copper, silver or gold and another layer of lead or cadmium. The metal layers provide an electrochemically active surface for the reduction and oxidation activity of the cell which dramatically increases the current density at the electrodes.
An electrical storage cell of the reduction oxidation (REDOX) type is divided into anode and cathode compartments by a membrane, each compartment having a circulating fluid containing an ion couple for producing an electric potential at respective solid inert electrodes disposed therein. The anode electrode is plated with one layer of copper, silver or gold and another layer of lead or cadmium. The metal layers provide an electrochemically active surface for the reduction and oxidation activity of the cell which dramatically increases the current density at the electrodes.
Description
6~
This invention rela-tes to electrical energy storage devices and particularly relates to electrically rechargeab~e reduction-oxidation (REDOX) Elow cell systems.
A need exists for storing bulk quantities of elec-trical power obtained from intermittent or random sources such as wind-driven generators, and solar cells~
Pumped water storage systems wherein water from a water storage pond at one level is directed to a water storage pond at a lower level through a hydro-electric plant having a water pumping capability has proven to be a viable method o~
energy storage. Unfortunately, such facilities are limited to areas where the terrain is suitable for providing water sources at different elevations.
A number of other methods have been considered in-cluding the storage of compressed air in large reservoirs, fly-wheels, capacitive storage, inductive storage and a number of electrochemical schemes. Electrochemical storage batteries are generally expensive.
Electrically rechargeable REDOX flow cell systems are well known and have a very high overall energy efficiency as compared to other systems. REDOX type cells also can be dis-charged more completely than second~ry battery syste~s. Addi-tionally, REDOX cells are inexpensive as compared to secondary batteries and do not deteriorate as significantly when repeatedly discharged and rec:harged.
United States Patent 3,996,064 is useful background for the understan~ing of the present invention. In that patent an electrically rechargeable REDOX flow cell is disclosed where-in an electric potential is obtained between electrodes dis-posed respectively in an anode fluid having a chromic/chromous -1- ~
:: :
~4~36~
couple and a cathode fluid having a ferrous/ferric couple. The anode and cathode fluids are separated by an ion selective mem-brane. The electrodes are both disclosed as comprised of porous graphite products which are inert to electrochemical reaction with the anode and cathode fluids while promoting the REDOX re-action on their surfaces.
It is an object of the invention to provide a REDOX
cell which will deliver much greater current for any given elec-trode surface area than prior art devices. It is another object of the invention to provide a REDOX type cell which will deliver an increasingly greater percentage of current when compared to prior art REDOX cells as the cell approaches a discharged con-dition.
In accordance with the invention, catalytic coatings are provided on the surface of the anode electrode to enhance the reduction and oxidation activity of the desired ions in the fluid. In the preferred embodiment a thin metal layer of copper, silver or gold and another layer of lead are deposited respect-ively on the anode electrode. In the iron/chromium fluid system of the preferred embodiment, the lead surface enhances the chrom-ium reduction during the charging of the cell and produces a 60-fold increase of reduction current density over an untreated electrode.
When the REDOX cell is being discharged, the lead also functions very well as a surface for the reversible electro-chemical oxidation of the chromous ions to chromic ions, however, the lead itself a:Lso undergoes electrochemical o~idation and is deplated from the anode surface.
The thin metal layer of copper, silver or gold, which becomes exposed to the anode fluid, provides an electro-`
chemically active surface for the rapid oxidation of the chromous ions, and at the same time is less subject to being oxidized than the lead. The copper produces a 50-fold increase in current density and the gold and silver both produce about a 90-fold in-crease over plain carbon electrodes. During the recharging process, the lead is replated onto the layer of copper, silver or gold and is again available to promote the reduction activity of the chromic ions.
Embodiments of the invention will now b~ described with reference to the accompanying drawings, in which:
Figure 1 is a cross-sectional view of the REDOX cell embodying the invention showing the anode and cathode ~luid supply systems schematically;
Figure 2 is a graph illustrating the increased current density in a REDOX cell embodying the invention;
Figure 3 is a graph illustrating current density versus potential for different electrode materials; and, Figure 4 illustrates current density versus poten-tial for a carbon electrode with a catalytic coating and utili~ing desired ions in the fluid to plate out on the coated electrode.
Referring now to Figure 1, there is shown a REDOX
c~ll 10 comprising container 11, divided into compartments 12 and 13 by an ion conductive membrane 14. The graphite electrode 15 is disposed in the chamber 12 and connected to an output terminal 6 while a graphite electrode 7 is disposed in compartment 13 and connected to an output terminal 18. Electrode 15 in the anode ~;
compartment 12 is coated with metal layers 16 and 17 to Da more fully described hereinafter. ~ ~
As shown, a cathode fluid from a cathode fluid ~ -source 19 is circulated by a pump 20 through compartment 13. ;
Similarly, anode fluid from an anode fluid source 21 is circula-ted by a pump 22 through the compartment 12.
In a preferred embodiment, the REDOX cell 10 utili-zes an iron/chromium system wherein the cathode fluid contains a ferrous/ferric couple while the anode fluid contains a chromic/
chromous couple. Both fluids are acidified solutions between 1 and 4 molars. The anode fluid preferably contains water and HCl (agueous solution of HCl) having dissolved therein a chromium chloride salt whereby cations in a reduced state are produced.
The cathode fluid likewise is water and HCl but has dissolved therein an iron chloride salt whereby cations in an oxidiæed state are produced. These fluids provide the desired couples in each of the chambers 12 and 13. A more complete disc~ussion of the couple, the fluid and electrode requirements and membrane considerations is given in United States Patent 3,996,064.
While the REDOX cell herein has been described as using an anode fluid having a chromous/chromic couple and a cathode fluid having a ferrous/ferric couple, other couples may be used as indicated in the aforementioned patent. For example, titanium chloride may be used in the anode fluid to produce the cations in the reduced state and vanadium chloride or manganese chloride may be used in the cathode fluid to produce the cations in the oxidized state.
In accordance with the present invention, it has been found that a coating of lead on the inert electrode 15 sub-stantially increases the current density of the electrode, and consequently, the current available at terminals 6 and 18. This results from the fact that chromic reduction has been found to occur very rapidly on the lead surface. At the same time lead 0 is also representative of a class of non-noble metals that , . . ~ .. : - -6~a3 possess a very high hydrogen over voltage, which advantageously results in a minimization of the rate of hydrogen evolution to preserve the electrical balance of the fluids. Al-though lead chloride is discussed ~erein, it is noted that cadmium chloride may be substituted for or used in combination with lead chloride. Cadmium chloride achieves the same results as lead chloride in increasing catalytic activi-ty of a carbon electrode for the reduction of chromic chloride with the simultaneous in-hibition of hydrogen evolution.
10 On a lead surface which was prepared by the electro-deposition of a very thin layer of lead onto a smooth carbon rod, the reduction current was measured to be 12 mA/cm2 at an elec-trode potential of -600 millivolts (mV) versus a standard calomel electrode (SCE). Under like conditions, the reduction current for an untreated electrode was only 0.2 mA/cm2. Thus, the lead coating on a carbon rod provided a 60-fold increase of reduction current.
Referring now to Figure 2, there is shown graphi-cally the relative performance obtained over a wide range of potentials of a solution that contained no lead ions and one that contained 10 4 molars of lead ions.
The lead layer 17 may be coated onto the electrode 15 before it is disposed in chamber 12 to be contacted by the circulating anode with fluid. The lead layer may also be ob-tained by simply dissolving lead chloride in the anode fluid before charging lhe REDOX cell and allowing the lead, which is subject to anodic dissolution, to plate onto the electrode structure during the charing mode of the chromous/chromic re-action.
_ 5 _ '' : ' :' ' - ' ' ' . ~'-' ~-' - - "
~486~
As mentioned previously, each time the REDOX cell is discharged, the lead is deplated from the anode by electro-chemical oxidation and redissolved in the anode fluid. secause the carbon and graphite material of the electrode structure does not provide an active surface for the oxidation of the chromous ions, a further aspect of the invention is the provision of metal layer 16 as an electrochemically active surface between the lead layer and the electrode surface for this purpose. Metal layer 16 may be selected from the group comprising copper, silver and gold which have all been found to be electrochémically active surfaces for the rapid electrochemical oxidation of chromous ions, and at the same time, are less subject to being electrochemically oxi-dized than lead. Figure 3 graphically illustrates the current density versus potential for silver, copper and smooth carbon surface. As shown, at an electrode potential of -550 mV versus a saturated calomel electrode the rate of electrochemical oxi-dation of a chromous ion is less than 0.1 mAfcm2. Under the same conditions, the current produced by the silver surface is about 9 mA/cm2 which is about a 90-fold increase. A copper sur-face under the same conditions yields 5 mA/cm2 which is a 50-fold increase over a smooth carbon surface.
Referring now to Figure 4, there is graphically ; shown the current density obtained for various electrode poten-tials for the chromous/chromic couple where the anode electrode is coated with gold and wherein lead chloride is dissolved in the anode fluid to provide lead ions. With the gold coating on the anode electrode it will be seen at negative 550 mV versus the saturated calomel electrode the current for the electro oxidation of chromous ion is 9 mA/cm2. This is a 90~fold increase over a plain carbon elec-trode.
, :
The metal coating 16 of silver, gold or copper on the inert electrode is very -thin and may be applied by various procedures including electrodeposition, metal spraying, dipping or the like. The amount of metal in the coating is on the order or only a few molecular layers. A graphite felt was produced with 25 micrograms of gold per cm2 of projected area. This pro-vided suitable electrode performance during discharge. The lead coating which goes over the silver, gold or copper coating on the inert electrode, whether applied before the electrode is in-lQ serted in the anode chamber or by deposition from the anode fluid, can also be as thin as several monolayers, where a monolayer is one molecule in thickness.
The gold, silver and copper catalysts which enhance the oxidation of chromous ions during the dischar~e cycle may also be dissolved in the anode solution as salts to provide in-situ activation of the anode electrode. They can also be incor-porated into the negative carbon electrode by saturating the electrode with a salt solution of gold, silvex or copper followed by heat treatment to dry it.
It will be understood that changes and modifications may be made to the above described inventions by those skilled in ;~
the art without departing from the spirit and scope of the inven-tion as set forth in the clalms appended hereto.
' -: ~
This invention rela-tes to electrical energy storage devices and particularly relates to electrically rechargeab~e reduction-oxidation (REDOX) Elow cell systems.
A need exists for storing bulk quantities of elec-trical power obtained from intermittent or random sources such as wind-driven generators, and solar cells~
Pumped water storage systems wherein water from a water storage pond at one level is directed to a water storage pond at a lower level through a hydro-electric plant having a water pumping capability has proven to be a viable method o~
energy storage. Unfortunately, such facilities are limited to areas where the terrain is suitable for providing water sources at different elevations.
A number of other methods have been considered in-cluding the storage of compressed air in large reservoirs, fly-wheels, capacitive storage, inductive storage and a number of electrochemical schemes. Electrochemical storage batteries are generally expensive.
Electrically rechargeable REDOX flow cell systems are well known and have a very high overall energy efficiency as compared to other systems. REDOX type cells also can be dis-charged more completely than second~ry battery syste~s. Addi-tionally, REDOX cells are inexpensive as compared to secondary batteries and do not deteriorate as significantly when repeatedly discharged and rec:harged.
United States Patent 3,996,064 is useful background for the understan~ing of the present invention. In that patent an electrically rechargeable REDOX flow cell is disclosed where-in an electric potential is obtained between electrodes dis-posed respectively in an anode fluid having a chromic/chromous -1- ~
:: :
~4~36~
couple and a cathode fluid having a ferrous/ferric couple. The anode and cathode fluids are separated by an ion selective mem-brane. The electrodes are both disclosed as comprised of porous graphite products which are inert to electrochemical reaction with the anode and cathode fluids while promoting the REDOX re-action on their surfaces.
It is an object of the invention to provide a REDOX
cell which will deliver much greater current for any given elec-trode surface area than prior art devices. It is another object of the invention to provide a REDOX type cell which will deliver an increasingly greater percentage of current when compared to prior art REDOX cells as the cell approaches a discharged con-dition.
In accordance with the invention, catalytic coatings are provided on the surface of the anode electrode to enhance the reduction and oxidation activity of the desired ions in the fluid. In the preferred embodiment a thin metal layer of copper, silver or gold and another layer of lead are deposited respect-ively on the anode electrode. In the iron/chromium fluid system of the preferred embodiment, the lead surface enhances the chrom-ium reduction during the charging of the cell and produces a 60-fold increase of reduction current density over an untreated electrode.
When the REDOX cell is being discharged, the lead also functions very well as a surface for the reversible electro-chemical oxidation of the chromous ions to chromic ions, however, the lead itself a:Lso undergoes electrochemical o~idation and is deplated from the anode surface.
The thin metal layer of copper, silver or gold, which becomes exposed to the anode fluid, provides an electro-`
chemically active surface for the rapid oxidation of the chromous ions, and at the same time is less subject to being oxidized than the lead. The copper produces a 50-fold increase in current density and the gold and silver both produce about a 90-fold in-crease over plain carbon electrodes. During the recharging process, the lead is replated onto the layer of copper, silver or gold and is again available to promote the reduction activity of the chromic ions.
Embodiments of the invention will now b~ described with reference to the accompanying drawings, in which:
Figure 1 is a cross-sectional view of the REDOX cell embodying the invention showing the anode and cathode ~luid supply systems schematically;
Figure 2 is a graph illustrating the increased current density in a REDOX cell embodying the invention;
Figure 3 is a graph illustrating current density versus potential for different electrode materials; and, Figure 4 illustrates current density versus poten-tial for a carbon electrode with a catalytic coating and utili~ing desired ions in the fluid to plate out on the coated electrode.
Referring now to Figure 1, there is shown a REDOX
c~ll 10 comprising container 11, divided into compartments 12 and 13 by an ion conductive membrane 14. The graphite electrode 15 is disposed in the chamber 12 and connected to an output terminal 6 while a graphite electrode 7 is disposed in compartment 13 and connected to an output terminal 18. Electrode 15 in the anode ~;
compartment 12 is coated with metal layers 16 and 17 to Da more fully described hereinafter. ~ ~
As shown, a cathode fluid from a cathode fluid ~ -source 19 is circulated by a pump 20 through compartment 13. ;
Similarly, anode fluid from an anode fluid source 21 is circula-ted by a pump 22 through the compartment 12.
In a preferred embodiment, the REDOX cell 10 utili-zes an iron/chromium system wherein the cathode fluid contains a ferrous/ferric couple while the anode fluid contains a chromic/
chromous couple. Both fluids are acidified solutions between 1 and 4 molars. The anode fluid preferably contains water and HCl (agueous solution of HCl) having dissolved therein a chromium chloride salt whereby cations in a reduced state are produced.
The cathode fluid likewise is water and HCl but has dissolved therein an iron chloride salt whereby cations in an oxidiæed state are produced. These fluids provide the desired couples in each of the chambers 12 and 13. A more complete disc~ussion of the couple, the fluid and electrode requirements and membrane considerations is given in United States Patent 3,996,064.
While the REDOX cell herein has been described as using an anode fluid having a chromous/chromic couple and a cathode fluid having a ferrous/ferric couple, other couples may be used as indicated in the aforementioned patent. For example, titanium chloride may be used in the anode fluid to produce the cations in the reduced state and vanadium chloride or manganese chloride may be used in the cathode fluid to produce the cations in the oxidized state.
In accordance with the present invention, it has been found that a coating of lead on the inert electrode 15 sub-stantially increases the current density of the electrode, and consequently, the current available at terminals 6 and 18. This results from the fact that chromic reduction has been found to occur very rapidly on the lead surface. At the same time lead 0 is also representative of a class of non-noble metals that , . . ~ .. : - -6~a3 possess a very high hydrogen over voltage, which advantageously results in a minimization of the rate of hydrogen evolution to preserve the electrical balance of the fluids. Al-though lead chloride is discussed ~erein, it is noted that cadmium chloride may be substituted for or used in combination with lead chloride. Cadmium chloride achieves the same results as lead chloride in increasing catalytic activi-ty of a carbon electrode for the reduction of chromic chloride with the simultaneous in-hibition of hydrogen evolution.
10 On a lead surface which was prepared by the electro-deposition of a very thin layer of lead onto a smooth carbon rod, the reduction current was measured to be 12 mA/cm2 at an elec-trode potential of -600 millivolts (mV) versus a standard calomel electrode (SCE). Under like conditions, the reduction current for an untreated electrode was only 0.2 mA/cm2. Thus, the lead coating on a carbon rod provided a 60-fold increase of reduction current.
Referring now to Figure 2, there is shown graphi-cally the relative performance obtained over a wide range of potentials of a solution that contained no lead ions and one that contained 10 4 molars of lead ions.
The lead layer 17 may be coated onto the electrode 15 before it is disposed in chamber 12 to be contacted by the circulating anode with fluid. The lead layer may also be ob-tained by simply dissolving lead chloride in the anode fluid before charging lhe REDOX cell and allowing the lead, which is subject to anodic dissolution, to plate onto the electrode structure during the charing mode of the chromous/chromic re-action.
_ 5 _ '' : ' :' ' - ' ' ' . ~'-' ~-' - - "
~486~
As mentioned previously, each time the REDOX cell is discharged, the lead is deplated from the anode by electro-chemical oxidation and redissolved in the anode fluid. secause the carbon and graphite material of the electrode structure does not provide an active surface for the oxidation of the chromous ions, a further aspect of the invention is the provision of metal layer 16 as an electrochemically active surface between the lead layer and the electrode surface for this purpose. Metal layer 16 may be selected from the group comprising copper, silver and gold which have all been found to be electrochémically active surfaces for the rapid electrochemical oxidation of chromous ions, and at the same time, are less subject to being electrochemically oxi-dized than lead. Figure 3 graphically illustrates the current density versus potential for silver, copper and smooth carbon surface. As shown, at an electrode potential of -550 mV versus a saturated calomel electrode the rate of electrochemical oxi-dation of a chromous ion is less than 0.1 mAfcm2. Under the same conditions, the current produced by the silver surface is about 9 mA/cm2 which is about a 90-fold increase. A copper sur-face under the same conditions yields 5 mA/cm2 which is a 50-fold increase over a smooth carbon surface.
Referring now to Figure 4, there is graphically ; shown the current density obtained for various electrode poten-tials for the chromous/chromic couple where the anode electrode is coated with gold and wherein lead chloride is dissolved in the anode fluid to provide lead ions. With the gold coating on the anode electrode it will be seen at negative 550 mV versus the saturated calomel electrode the current for the electro oxidation of chromous ion is 9 mA/cm2. This is a 90~fold increase over a plain carbon elec-trode.
, :
The metal coating 16 of silver, gold or copper on the inert electrode is very -thin and may be applied by various procedures including electrodeposition, metal spraying, dipping or the like. The amount of metal in the coating is on the order or only a few molecular layers. A graphite felt was produced with 25 micrograms of gold per cm2 of projected area. This pro-vided suitable electrode performance during discharge. The lead coating which goes over the silver, gold or copper coating on the inert electrode, whether applied before the electrode is in-lQ serted in the anode chamber or by deposition from the anode fluid, can also be as thin as several monolayers, where a monolayer is one molecule in thickness.
The gold, silver and copper catalysts which enhance the oxidation of chromous ions during the dischar~e cycle may also be dissolved in the anode solution as salts to provide in-situ activation of the anode electrode. They can also be incor-porated into the negative carbon electrode by saturating the electrode with a salt solution of gold, silvex or copper followed by heat treatment to dry it.
It will be understood that changes and modifications may be made to the above described inventions by those skilled in ;~
the art without departing from the spirit and scope of the inven-tion as set forth in the clalms appended hereto.
' -: ~
Claims (14)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A REDOX cell having first and second chambers separated by an ion permeable membrane; an anode fluid in the first chamber; and a cathode fluid in the second chamber;
an anode electrode in said first chamber, said electrode being electrically conductive but inert with respect to the anode fluid;
a cathode electrode in said second chamber, said electrode being electrically conductive but inert with respect to the cathode fluid, said anode fluid having lead chloride salt dissolved therein whereby lead is plated onto the anode electrode when the cell is initially charged.
an anode electrode in said first chamber, said electrode being electrically conductive but inert with respect to the anode fluid;
a cathode electrode in said second chamber, said electrode being electrically conductive but inert with respect to the cathode fluid, said anode fluid having lead chloride salt dissolved therein whereby lead is plated onto the anode electrode when the cell is initially charged.
2. The REDOX cell of claim 1 wherein the lead ions in said anode fluid are in the amount of 10-4/liter of the fluid to 10-5 M/liter.
3. The REDOX cell of claim 1 wherein said anode and cathode electrodes are selected from the group of materials consisting of carbon and graphite.
4. The REDOX cell of claim 1 wherein said anode is coated with a thin layer of metal selected from the group consisting of silver, gold and copper to inhibit the oxidation of lead ions when the cell is being discharged.
5. The REDOX cell of claim 4 wherein said thin layer of metal is 2-5 monolayers thick and amounts to 10-4 to 10-5 M/liter of anode fluid.
6. A REDOX cell having first and second chambers separated by an ion permeable membrane;
an anode fluid in the first chamber;
a cathode fluid in the second chamber;
an anode electrode in said first chamber, said electrode being electrically conductive but inert with respect to the anode fluid;
a cathode electrode in said second chamber, said electrode being electrically conductive but inert with respect to the cathode fluid, said anode electrode having thereon a thin coating of lead.
an anode fluid in the first chamber;
a cathode fluid in the second chamber;
an anode electrode in said first chamber, said electrode being electrically conductive but inert with respect to the anode fluid;
a cathode electrode in said second chamber, said electrode being electrically conductive but inert with respect to the cathode fluid, said anode electrode having thereon a thin coating of lead.
7. The REDOX cell of claim 1 wherein said coating of lead is about 2-5 monolayers thick.
8. The REDOX cell of claim 7 wherein the. amount of lead is 10-4 to 10-5 M/liter of anode fluid.
9. The REDOX cell of claim 6 wherein a coating selected from the group of metals consisting of silver, gold and copper is disposed between the anode electrode and the lead coating.
10. The REDOX cell of claim 4 wherein said coating disposed between the anode electrode and the lead coating is about 2-5 monolayers thick.
11, A REDOX cell having first and second chambers separated by an ion permeable membrane; an anode fluid in the first chamber; and a cathode fluid in the second chamber;
an anode electrode in said first chamber, said electrode being electrically conductive but inert with respect to the anode fluid;
a cathode electrode in said second chamber, said electrode being electrically conductive but inert with respect to the cathode fluid, said anode fluid having cadmium salt dissolved therein whereby cadmium is plated onto the anode electrode when the cell is initially charged.
an anode electrode in said first chamber, said electrode being electrically conductive but inert with respect to the anode fluid;
a cathode electrode in said second chamber, said electrode being electrically conductive but inert with respect to the cathode fluid, said anode fluid having cadmium salt dissolved therein whereby cadmium is plated onto the anode electrode when the cell is initially charged.
12. A REDOX cell having first and second chambers separated by an ion permeable membrane;
an anode fluid in the first chamber;
a cathode fluid in the second chamber;
an anode electrode in said first chamber, said electrode being electrically conductive but inert with respect to the anode fluid;
a cathode electrode in said second chamber, said electrode being electrically conductive but inert with respect to the cathode fluid, said anode electrode having thereon a thin coating of cadmium.
an anode fluid in the first chamber;
a cathode fluid in the second chamber;
an anode electrode in said first chamber, said electrode being electrically conductive but inert with respect to the anode fluid;
a cathode electrode in said second chamber, said electrode being electrically conductive but inert with respect to the cathode fluid, said anode electrode having thereon a thin coating of cadmium.
13. The REDOX cell of claim 12 wherein said coating of cadmium is about 2-5 monolayers thick.
14. A REDOX cell having first and second chambers separated by an ion permeable membrane; an anode fluid in the first chamber; and a cathode fluid in the second chamber;
an anode electrode in said first chamber, said electrode being electrically conductive but inert with respect to the anode fluid;
a cathode electrode in said second chamber, said electrode being electrically conductive but inert with respect to the cathode fluid, said anode fluid having dissolved therein more than one salt selected from the group consisting of lead chloride and cadmium chloride.
an anode electrode in said first chamber, said electrode being electrically conductive but inert with respect to the anode fluid;
a cathode electrode in said second chamber, said electrode being electrically conductive but inert with respect to the cathode fluid, said anode fluid having dissolved therein more than one salt selected from the group consisting of lead chloride and cadmium chloride.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000340611A CA1148610A (en) | 1979-11-26 | 1979-11-26 | Catalyst surface for the chromous/chromic redox couple |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000340611A CA1148610A (en) | 1979-11-26 | 1979-11-26 | Catalyst surface for the chromous/chromic redox couple |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1148610A true CA1148610A (en) | 1983-06-21 |
Family
ID=4115690
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000340611A Expired CA1148610A (en) | 1979-11-26 | 1979-11-26 | Catalyst surface for the chromous/chromic redox couple |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1148610A (en) |
-
1979
- 1979-11-26 CA CA000340611A patent/CA1148610A/en not_active Expired
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