WO1993000683A1

WO1993000683A1 - Apparatus for producing heat from deuterated film-coated palladium

Info

Publication number: WO1993000683A1
Application number: PCT/US1992/004241
Authority: WO
Inventors: Michael C. H. Mckubre; Steven Crouch-Baker; Francis L. Tanzella; Stuart I. Smedley; Joseph Santucci; Romeu C. Rocha-Filho
Original assignee: Electric Power Research Institute, Inc.
Priority date: 1991-06-27
Filing date: 1992-05-20
Publication date: 1993-01-07
Also published as: AU2316292A

Abstract

An electrolysis system (1) for generating excess heat has a direct current source (11) coupled between an anode (9) and a cathode (7). The electrolyte (5) is typically a solution of lithium deuteroxide in heavy water. The cathode (7) has a surface layer (8) that is comprised primarily of palladium. The current flow through the cell (12, 67) causes the palladium to become loaded with deuterium. The surface layer (8) is at least partially coated with a film (10) that enhances the loading of deuterium into the layer (8). The film (10) is comprised of hydrated metal oxide-based compounds, where the metal may be aluminum, silicon, boron, barium, calcium, copper, iron, lithium, magnesium, nickel, scandium, titanium, vanadium, yttrium, or zirconium. The film (10) is formed from material in the electrolyte (5) by the current flow. In an alternative embodiment of the invention, the film (10) is pre-formed on the surface of the cathode (7) before immersion into the electrolyte (5).

Description

APPARATUS FOR PRODUCING HEAT FROM DEUTERATED FILM-COATED PALLADIUM

BACKGROUND OF THE INVENTION

1 . Field of the Invention

This invention pertains generally to the field of devices for producing heat energy by charging palladium with deuterium, and more particularly, to such devices where this charging is carried out by electrochemical means.

2. Description of the Background Art

In March, 1989 it was announced that scientists at the University of Utah had constructed a simple cell that generates large amounts of heat, far in excess of the energy that could be produced by known chemical processes. This announcement was followed shortly thereafter by a paper by M. Fleischmann, S. Pons and . Hawkins, "Electrochemically Induced Nuclear Fusion of Deuterium", Journal of Electroanalytical Chemistry, Vol. 261, p. 301 (April 1989), describing their experiments at the University of Utah. These experiments were calorimetric measurements on electrochemical cells with platinum anodes and palladium cathodes driven by a source of electric current through the cell. The electrolytes contained heavy water, and deuterium from the electrolyte was loaded into the palladium cathodes . Depending on the amount of electric current, it was found that these cells generated anomalously large quantities of heat.

In the calorimetry experiments of these authors and the other experiments discussed herein, one compares the known and measured sources of input energy or power to the system with the observed output energy or power. The difference between the output energy and input energy is defined as the "excess heat". Fleischmann and his co-workers have reported that, in addition to the production of large amounts of excess heat "in these cells, there is some evidence of neutron and tritium production. They concluded that energy was being produced by nuclear fusion, specifically the D-D fusion reaction, involving the deuterium nuclei in the 9 palladium. Since these experiments were conducted at room temperatures, in stark contrast to the commonly known examples of nuclear fusion reactions which require very high temperatures, this class of experiments has been given collectively the generic title of "cold fusion".

These experiments have been repeated independently by other researchers, and similar calorimetry experiments have also been carried out to detect indications of nuclear processes. The observation of these phenomena have been confirmed in many cases. The state of this art in 1990 was substantially summarized in the proceedings of The First Annual Conference on Cold Fusion, held on March 28 - 31, 1990 in Salt Lake City, Utah. Hea -producing cells have been constructed using a variety of materials for the electrodes and the electrolyte. In particular, cells have been constructed with electrolytes that contain LiOD (lithium deuteroxide) , NaOD, KOD, Fe, Ag, Hg, Li₂S0₄, As₂0₃, and uranium, in addition to heavy water. Lithium deuteroxide is a commonly used electrolytic ingredient.

Cathodes have been fabricated from titanium and a variety of palladium alloys, besides pure palladium. Some researchers have reported deposits of contaminant materials on the cathode during the electrolysis process. These deposits degrade the energy production process by impeding the current flow and interfering with the deuterium loading.

SUMMARY OF THE INVENTION

The present invention provides an electrolysis system 1 for generating excess heat, having a direct current source 11 coupled between an anode 9. and a cathode 7_, with both electrodes at least partially immersed in an electrolyte 5_ in container 3.. The current source 11 drives electric current through the electrolyte 5_. The electrolyte 5_ is preferably a solution of lithium deuteroxide in heavy water (D2O) . The cathode 7. is comprised primarily of palladium, with a surface film designed to enhance the deuterium loading process. This surface film is preferably a hydrated metal oxide-based compound that is permeable to deuterium, and a variety of metals are useful in this film material. The film promotes deuterium loading by inhibiting the formation of

D₂ gas bubbles at the cathode surface, by blocking the anode material ions in the electrolyte from cathode electrons to prevent the formation of anode material deposits on the cathode, and by coating over cracks and defects in the cathode surface.

It is an object of this invention to provide a device for generating excess heat by the electrochemical loading of palladium cathodes with deuterium, in which the surfaces of said cathodes are at least partially coated with a film that enhances the loading process.

A second object of this invention is to provide a device for generating excess heat by the electrochemical loading of palladium cathodes with deuterium, in which the formation of deuterium gas bubbles at the cathode surface is inhibited.

Another object of this invention is to provide a device for generating excess heat by the electrochemical loading of palladium cathodes with deuterium, in which the formation of anode material deposits on the cathode is prevented.

Yet another object of this invention is to provide a device for generating excess heat by the electrochemical loading of palladium cathodes with deuterium, in which a coating is provided over the cathode surface to mitigate the deleterious effects of cracks and defects in the cathode surface. These and other objects, advantages, characteristics and features of this invention may be better understood by examining the following drawings together with the detailed description of the preferred embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a schematic diagram of an electrolysis system 1 for generating excess heat according to the present invention, showing a partially cross sectioned elevational view of an electrolytic cell 12. embodying the invention.

Figure 2 is a cross sectioned elevational view of the lower portion of the cathode 7_ of Figure 1, showing the film layer 10 over the palladium cathode surface 8. according to the present invention.

Figure 3 is a cross sectional front view of an electrolytic cell 67. embodying the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Figure 1 is a schematic diagram of an electrolysis system 1 for generating excess heat according to the present invention, for loading deuterium into a palladium cathode 7_. This cathode 7. and an anode 9. are at least partially immersed in an electrolyte 5_ in container 3_. The cathode 7. and anode .9. are coupled to a current generator 11 which drives a direct current from the anode 5_. to the cathode 2 within the electrolyte 5_. The entire system may be enclosed in a sealed enclosure 2., which may also serve as a heat exchanger or may comprise various heat exchange devices, well known in the art, for extracting and transferring heat from the system.

The electrolyte 5_ contains heavy water, specifically D₂0, and also preferably LiOD, typically a 1 molar solution. The cathode 7_ is preferably fabricated from palladium; however various alloys of palladium may also be used. Since the active region of the cathode 7_ is in the vicinity of the surface, the cathode 7. may actually be a layer of palladium over a bulk region of a conducting metal having a small deuterium diffusivity, such as copper. The anode 9. is preferably fabricated from palladium, platinum, or some stable non-elemental metallic conductor material. The bulk palladium used in practicing the invention should be of high purity. It is desirable to anneal out crystal imperfections and volatilize impurities, and to minimize stresses that may lead to cracks in the palladium surface which will limit the attainable amount of deuterium loading. Oxidation of the surface by 0₂ or H₂0 should also be avoided for the same reason. Preferably the palladium is annealed in a vacuum furnace at 800°C for three hours and then allowed to cool in 1 atmosphere of D gas or argon. After cooling, the Pd surface is etched in deuterated aqua regia, and then rinsed in D 0.

It is also desirable to minimize the amount of H₂0, 0₂, and C0₂ in the electrolyte 5_. Preferably the solution is formed by allowing pure Li metal or Li 0 to react with D₂0 of high isotopic purity in an inert gas environment.

The electrolyte container 3_ should be fabricated from materials that will not form deposits on the surface of the cathode 7. that inhibit the degree of deuterium loading. Two examples of materials that are satisfactory are quartz glass and polytetrafluoroethylene (PTFE) .

The cathode 7_ is preferably precharged at a moderate current density (between 10 and 100 mA/cm²) for a time corresponding to several diffusion periods of deuterium in palladium. This time is typically 3 to 10 days. This precharging period facilitates the subsequent accumulation of deuterium in the cathode. The production of excess heat is then initiated by increasing the current density continuously up to a threshold level.

Referring now to Figure 2, the palladium cathode 7. is shown as a layer 8. of palladium over a core 6. of conducting metal that may be impermeable to deuterium, such as copper. Since the deuterium loading takes place only over a limited region near the cathode surface, this inner core 6_. does not play an active role in the heat generation process. The film 10 over the surface of the palladium layer 8. enhances the loading of deuterium into the palladium at the surface covered by the film.

This film 10. may be coated on the surface 8_. of the palladium prior to the insertion of the cathode 7_. into the electrolyte 5_. Alternatively, the film 10. may be formed in situ by introducing additive metal species into the electrolyte 5_ and maintaining a moderate current density for a sufficient period to allow the film 10_ to form on the cathode surface 8.. The preferred metal species comprise aluminum, silicon, and boron. Other suitable metal species include barium, calcium, copper, iron, lithium, magnesium, nickel, scandium, titanium, vanadium, yttrium, and zirconium. When formed in situ, the film 10_. may not be of uniform composition or structure. It may comprise, for example, a hydrated oxide-based compound containing the particular metal species introduced into the electrolyte 5_. The compound may be an oxide or a hydroxide of the metal, for example.

The film 10_ enhances the deuterium loading process by several mechanisms. First, the film 10. is permeable to deuterium-transporting ions, and facilitates deuterium transport to the Pd layer 8., while at least partially blocking the transport of impurity cations from the electrolyte 5. and electrons from the palladium 8_ that otherwise could cause the impurity materials to deposit onto the surface 8_. of the cathode 7_. These deposits can inhibit deuterium absorption by forming an impermeable layer, or by catalyzing the alternate competing process of recombination: D_ads + D_ads ^ D₂ (gas) .

Second, film 10. hinders recombination by blocking molecular adsorption sites and preventing atomic and molecular diffusion on the surface 8. of the cathode 7..

Preventing recombination increases absorption efficiency. Third, film 10 inhibits the nucleation of D gas bubbles, thereby increasing the effective pressure of deuterium and the limit of loading (D/Pd) . Finally, to the extent that the film 10 forms over cracks and imperfections in the palladium surface 8_, deloading of deuterium at these sites is reduced or prevented.

Figure 3 is a cross sectional front view of an electrolytic cell .62 embodying the present invention. This cell operates at approximately atmospheric pressure. Vessel .69 is constructed of aluminum and has a cylindrical sleeve shape with an internal surface of PTFE. The palladium cathode 5_5_ is disposed along the central axis of the vessel ϋ_9. This cathode 5_5_ is a 3 mm diameter 3 cm long rod, machined from 1/8" (typically) pure Pd wire. Prior to insertion, the cathode 5_5 is solvent cleaned, vacuum annealed at 800°C for between 2 and 3 hours, and slowly cooled in an argon atmosphere. Finally it is dipped in heavy aqua regia for 20 seconds and rinsed with heavy water.

The electrolysis portion of the cell 67_ is exposed only to materials from the group comprising Pd, Pt, quartz glass and PTFE. Anode .65. consists of a 1 meter long, 0.5 mm diameter, Pt wire wound around a cage 23 of five quartz glass rods held in place by two PTFE disks 75. The wire _6_5_ is held in place by attachment to 2 mm Pd mounting posts 29. mounted on the top PTFE disk 75. The electrolyte 21 separates the cathode 5J5 and anode 65. Reference electrode j53. is adjacent to cathode 55. All surfaces of the cell ξj_ are solvent cleaned and rinsed. The anode cage 23. is further washed with aqua regia and rinsed with D₂0. An external 180 ohm heater is wound around the outside of vessel J59. within specially machined grooves on the surface 5_9 of vessel 69_. These grooves are omitted from the drawing of Figure 3. The cell _ is assembled with minimum exposure to air or moisture.

The electrolyte 21 is preferably prepared immediately prior to use and added to the vessel .69. before sealing the cell 67_ . In the illustrated embodiment, tube 81 is a 1/8" outside diameter nickel tube. The vessel j6_9 is preferably pressurized with deuterium. a

The existence of the film 10. and its electrical characteristics can be determined by measuring the ac impedance between the electrolyte 5. and the cathode 2 as a function of frequency. In the embodiment discussed here, these measurements were made over a frequency range between 0.1 Hz and 10,000 Hz. These data may be analyzed to provide information about the electrochemical kinetic processes of electron transfer, mass transport of product and reactant species, and resistance and reactance of surface films 10_. The information about the characteristics of the film 10. is based on these measurements and analyses.

To illustrate the operation of the invention, a calorimetry experiment was performed with this apparatus using an electrolyte that was a 1.0 M solution of LiOD in heavy water with 200 pp (molar) Al, manufactured by adding 0.175 g of Li metal and approximately 7 mg of pure Al foil to 25 ml D 0. This procedure was carried out under a nitrogen atmosphere. The calorimetry experiment was performed over a total duration of 1630 hours. Excess heat was first observed after 308 hours of electrolysis and was observed on ten separate occasions. In all cases the production of excess heat was initiated during and persisted after the conclusion of an increasing current ramp. The maximum excess power observed was 1.0 watt (10% in excess of the input power); the total excess of energy was 1.08 megajoules (MJ) , or 45 MJ/mole of Pd.

The effect of the film 10 in facilitating heat generation is displayed by varying the amount of aluminum in the electrolyte 5_ and measuring the resistivity of the loaded palladium 8., which gives a measure of the degree of deuterium loading, or the atomic ratio D/Pd. This ratio was measured for the cell with an electrolyte containing no aluminum, and found to be 0.945. When aluminum was added to the electrolyte in small amounts the ratio D/Pd increased, up to a value 0.978. This increase corresponds to a change in deuterium fugacity from approximately 10° atmospheres to approximately 2 x 10⁸ atmospheres. It was also found that the presence of the film 10 allowed this high loading to be maintained for long periods of time, of the order of weeks or more. In contrast, in the absence of the film 10 the sustained current densities at the cathode surface 3. makes available to this surface 8. many species that are capable of discharging on the Pd metal and destroying the interfacial properties that are necessary for high loading. This results in unloading of the palladium even at modest current densities.

The foregoing description of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and many modifications and variations are possible in light of the above teaching. The embodiment has been chosen and described in order to best explain the principles of the invention and its practical applications to thereby enable others skilled in the art to best utilize the invention in various embodiments and with various modifications as are suitable to the particular use contemplated. It is intended that the spirit and scope of the invention are to be defined by reference to the claims appended hereto.

Claims

What is claimed is:

1. Apparatus for producing heat, said apparatus comprising: an electrolyte comprising deuterium and conducting ions; at least partially immersed in the electrolyte, an anode for interacting with conducting ions within the electrolyte; at least partially immersed in the electrolyte, a cathode having a palladium surface, said deuterium accumulating within the cathode surface, said surface being at least partially coated by a film such that the accumulation of said deuterium within said cathode surface is enhanced by said film; and current generating means coupled to said anode and said cathode for producing an electric current in said electrolyte.

2. Apparatus as recited in claim 1, wherein the current produced by said current generating means causes deuterium to be loaded into said cathode.

3. Apparatus as recited in claim 1, wherein said film is formed by the current produced by said current generating means from material in said electrolyte.

4. Apparatus as recited in claim 3, wherein said film is abricated from hydrated metal oxide-based compounds.

5. Apparatus as recited in claim 4, wherein said metal is selected from the group consisting of aluminum, silicon, boron, barium, calcium, copper, iron, lithium, magnesium, nickel, scandium, titanium, vanadium, yttrium, and zirconium.

6. Apparatus as recited in claim 4, wherein said film is fabricated from hydrated metal oxides.

7. Apparatus as recited in claim 6, wherein said metal is selected from the group consisting of aluminum, silicon, boron, barium, calcium, copper, iron, lithium, magnesium, nickel, scandium, titanium, vanadium, yttrium, and zirconium.

8. Apparatus as recited in claim 4, wherein said film is fabricated from hydrated metal hydroxides.

9. Apparatus as recited in claim 8, wherein said metal is selected from the group consisting of aluminum, silicon, boron, barium, calcium, copper, iron, lithium, magnesium, nickel, scandium, titanium, vanadium, yttrium, and zirconium.

10. Apparatus as recited in claim 1, wherein said film is fabricated from hydrated metal oxide-based compounds.

11. Apparatus as recited in claim 10, wherein said metal is selected from the group consisting of aluminum, silicon, boron, barium, calcium, copper, iron, lithium, magnesium, nickel, scandium, titanium, vanadium, yttrium, and zirconium.

12. Apparatus as recited in claim 10, wherein said film is fabricated from hydrated metal oxides .

13. Apparatus as recited in claim 12, wherein said metal is selected from the group consisting of aluminum, silicon, boron, barium, calcium, copper, iron, lithium, magnesium, nickel, scandium, titanium, vanadium, yttrium, and zirconium.

14. Apparatus as recited in claim 10, wherein said film is fabricated from hydrated metal hydroxides.

15. Apparatus as recited in claim 14, wherein said metal is selected from the group consisting of aluminum, 1? silicon, boron, barium, calcium, copper, iron, lithium, magnesium, nickel, scandium, titanium, vanadium, yttrium and zirconium.

16. Apparatus as recited in claim 1, wherein said film inhibits the formation of deuterium gas bubbles at said cathode surface.

17. Apparatus as recited in claim 1, wherein said film blocks cation material in said electrolyte from cathode electrons to prevent the formation of cation material deposits on said cathode.

18. Apparatus as recited in claim 1, wherein said film forms a coating over cracks and defects in said cathode surface.