WO1993000684A1

WO1993000684A1 - Apparatus for producing heat from deuterated palladium alloys

Info

Publication number: WO1993000684A1
Application number: PCT/US1992/004259
Authority: WO
Inventors: Steven Crouch-Baker; Michael C. H. Mckubre; Stuart I. Smedley; Francis L. Tanzella
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: AU2010492A

Abstract

An electrolysis system (1) for generating excess heat has a direct current source (11) coupled between an anode (9) and a cathode (7), with both electrodes (9, 7) immersed in an electrolyte (5). The current source (11) drives electric current through the electrolyte (5) from the anode (9) to the cathode (7). The electrolyte (5) is typically a solution of lithium deuteroxide and boric acid in heavy water. The cathode (7) is comprised primarily of palladium. The current flow through the cell (12, 67) causes the palladium to become loaded with boron and deuterium, which substantially increases the efficiency of excess heat production and lowers the current threshold for excess heat generation. In an alternative version, the surface of the cathode (7) is fabricated from an alloy of boron and palladium.

Description

TITLE OF THE INVENTION

Apparatus For Producing Heat from Deuterated Palladium Alloys

CROSS-REFERENCE TO RELATED APPLICATIONS This application concerns subject matter that is related to the subject matter disclosed in the following applications :

1. "Apparatus For Producing Heat From Deuterated Palladium"; Michael C. H. McKubre, Francis L. Tanzella, Stuart I. Smedley, and Romeu C. Rocha-Filho; filed June 11, 1991.

2. "Methods For Producing Heat From Deuterated Palladium"; Michael C. H. McKubre, Romeu C. Rocha-Filho, Stuart I. Smedley, Francis L. Tanzella, Steven Crouch-Baker, Thomas O. Passell, and Joseph Santucci; filed June 11, 1991.

3. "Methods for Cleaning Cathodes"; Michael C. H. McKubre, Stuart I. Smedley, and Francis L. Tanzella; filed June 11, 1991. 4. "Methods For Forming Films on Cathodes";

Michael C. H. McKubre, Romeu C. Rocha-Filho, Stuart I. Smedley, Francis L. Tanzella, Steven Crouch-Baker, and Joseph Santucci; filed June 11, 1991. BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention pertains generally to the field of devices for producing heat energy by charging alloys of 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 M. 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 calori etric 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 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. Heat-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 (lithium sulphate) , AS2O3, 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. These alloys include palladium-silver, palladium-lithium, palladium-carbon, palladium-lithium-carbon, palladium-beryllium, and palladium-sulphur. Reference is made to the paper by E. Storms and C. Talbott entitled "A Study of Electrolytic Tritium Production", on page 149 of the above-mentioned conference proceedings, summarizing the results obtained from cells using a variety of cathode materials.

In particular, these authors report that two cathodes have been fabricated from an alloy of palladium-boron. The alloy was made by arc-melting palladium powder with boron in an argon atmosphere. The atomic ratio of boron to palladium was B/Pd = 0.028. One cathode was used in a cell having AS2O in the electrolyte, and a small amount of tritium was produced. The other cathode was operated in a cell with ordinary electrolyte; no tritium was produced. In neither case were there any observations of excess heat. The authors'^' conclusions are that the effect of a Pd-B alloy is uncertain, although under certain conditions the chance of tritium production seems to be improved.

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 1_, with both electrodes immersed in an electrolyte 5. in container 3.. The current source 1JL drives electric current through the electrolyte 5. from anode 9. to cathode 7.. The electrolyte 5 is a solution of lithium deuteroxide and boric acid in heavy water (D2O) . The cathode 7_. is comprised primarily of palladium. The current flow through the cell causes the palladium to become loaded with boron and deuterium. It is found that this charging of boron into the cathode 7. substantially increases the efficiency of production of excess heat, and lowers the current threshold for excess heat generation, compared to cells without boron. The cathode 1_ may include other elements besides palladium, deuterium and boron. Generally the cathode 1 also contains lithium from the LiOD in the electrolyte 5_- Other alloys of palladium such as Pd-Ag may be used as the host material. The distinctive feature of boron is that in the palladium crystal lattice it occupies octahedral interstitial sites which might otherwise be occupied by deuterium. This enhances the excess heat production process.

It is an object of this invention to provide a device for generating excess heat by the electrochemical charging of palladium alloys with deuterium. A second object of this invention is to provide a device for generating excess heat having an improved efficiency for the production of such excess heat.

Another object of this invention is to provide a device for generating excess heat in which the current threshold for excess heat production is substantially decreased.

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 embodiment.

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 J 2. embodying the invention. Figure 2 is a diagram of the face centered cubic

(FCC) crystal lattice structure of alloys of palladium that are useful in this invention, showing octahedral and tetrahedral interstitial sites on which alloy atoms may reside, for example. Figure 3 is a cross sectional front view of an electrolytic cell ξj_ 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 alloy cathode 1_ . This cathode J and an anode 9. are immersed in an electrolyte 5. in container 3.. The cathode 1_ and anode _ are coupled to a current generator 1_1 which drives a direct current from the anode 9. to the cathode 7 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 D2O, and also preferably LiOD, typically a 1 molar solution. In the preferred embodiment boric acid, H3BO3, is added to this solution to provide a source of boron for loading into the cathode 1_. This cathode 1_ is preferably fabricated from palladium; however various alloys of palladium may also be used, such as palladium-silver. Furthermore, boron may be preloaded into the cathode 1_, in which case Pd-B is the alloy. Finally, since the active region of the cathode 1_ is in the vicinity of the surface, the cathode 7. may actually be a layer of palladium alloy 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 O2 or H2O 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 D2 gas or argon. After cooling, the Pd surface is etched in deuterated aqua regia, and then rinsed in D₂0.

It is also desirable to minimize the amount of H O, O2, and CO2 n the electrolyte 5_. Preferably the solution is formed by allowing pure Li metal or Li2θ to react with D->0 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 2 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/cm^) 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, at standard temperature and pressure palladium is known to have a face centered cubic (FCC) crystal structure which is illustrated in this figure. The FCC lattice sites are indicated by the circles having horizontal hatchings. These sites are the locations of the palladium atoms in the crystal. Many alloys of palladium, such as Pd-Ag, also have this crystal structure. Palladium-silver is a substitutional alloy, in which the silver atoms occupy FCC lattice sites that would otherwise be occupied by palladium atoms.

The distinctive feature of deuterium (hydrogen) and boron is that these elements form interstitial alloys in palladium. (The term "alloys" is used here in its generalized sense of solid solutions, and is not limited to any specific fabrication process.) The palladium-hydrogen system has been extensively studied, and it is known that palladium has a propensity to absorb hydrogen, and that the hydrogen atoms preferably occupy the octahedral interstitial sites in the palladium lattice. These sites lie in the horizontal and vertical planes defined by the lattice sites, and each octahedral site lies midway between two neighboring lattice sites, as indicated in Figure 2 by the open circles . At a stoichiometric ratio of one-to-one, if all "the octahedral sites are occupied by hydrogen atoms, it will be seen from the figure that the hydrogen atoms form an interpenetrating FCC lattice within the palladium lattice. These remarks about the behavior of hydrogen apply also to deuterium, since the chemical properties of both atoms are identical.

The octahedral sites are not the only available sites for interstitial atoms to occupy. In Figure 2 the circles with diagonal hatching define the tetrahedral sites in the lattice. The names of these sites refer to the symmetry of their atomic environment. For example, at the octahedral sites the "nearest neighbor" palladium atoms (i.e. the palladium atoms closest to the site) define surrounding planes forming an octahedron, and thus these sites have "octahedral symmetry". The tetrahedral sites have a lower symmetry than the octahedral sites, and atoms at these sites have a higher energy. Therefore the octahedral sites are preferably occupied by the interstitial atoms, but at any finite temperature there is always some occupation of tetrahedral sites as well. Furthermore, hydrogen can be loaded at an atomic ratio of H/Pd greater than unity.

The palladium-boron system has also been studied, and reference is made to the article by H. A. Brodowsky and H.-J. Schaller, "Thermodynamics of Nonstoichiometric Interstitial Alloys. I. Boron in Palladium", Transactions of the Metallurgical Society of AIME, Vol. 246, p. 1015 (May 1969) . These authors have analyzed the thermodynamic measurements of the palladium-boron system up to concentrations of 23 percent boron, and determined that the boron atoms also occupy the octahedral interstitial sites in the palladium lattice. Their analysis further indicated that the energy gap between the octahedral sites and the tetrahedral sites is substantially greater for boron than for hydrogen (deuterium) .

These considerations imply that the effect of loading boron into the palladium lattice together with deuterium is that octahedral interstitial sites are occupied by boron atoms, and therefore blocked off from deuterium occupancy. For a given deuterium loading, the addition of boron causes deuterium atoms to be displaced from octahedral sites to other interstitial locations, such as tetrahedral sites. Alternatively, at a given boron loading, deuterium atoms occupy more non-octahedral interstitial sites as the deuterium loading increases. The increased occupancy of non-octahedral sites by deuterium atoms decreases the average distance between neighboring deuterium atoms in the lattice, according to the diagram in Figure 2. In the palladium lattice, the nearest neighbor octahedral sites are at a distance of 0.28 nanometers apart, while the corresponding nearest neighbor tetrahedral sites are at a distance of 0.19 nm from each other, and the corresponding nearest neighbor octahedral-tetrahedral distance is 0.17 nm. These numbers must be adjusted to take account of the variation in lattice parameters with boron and deuterium concentration, and the phase changes that occur in the solid solutions when the concentrations are increased to the phase boundaries . These corrections do not alter the overall conclusion that the addition of boron decreases the average D-D nearest neighbor distances. This decrease is associated with the production of excess heat in the present invention.

Figure 3 is a cross sectional front view of an electrolytic cell 61_ embodying the present invention. This cell operates at approximately atmospheric pressure. Vessel j59_ 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 .69.. This cathode 5_5_ is a 3 mm diameter 3 cm long rod, machined from 1/8" 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 6.7 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 73 of five quartz glass rods held in place by two PTFE disks 75. The wire .65. is held in place by attachment to 2 mm Pd mounting posts 7_9 mounted on the top PTFE disk 75. The electrolyte 7JL separates the cathode 5_5_ and anode 65. Reference electrode .63. is adjacent to cathode 55. All surfaces of the cell 62. are solvent cleaned and rinsed. The anode cage .13. is further washed with aqua regia and rinsed with D2O. An external 180 ohm heater is wound around the outside of vessel .69. within specially machined grooves on the surface 5_9_ of vessel .69_. These grooves are omitted from the drawing of Figure 3. The cell 62. 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 61_. In the illustrated embodiment, tube 8_1 is a 1/8" outside diameter nickel tube. The vessel j59 is preferably pressurized with deuterium.

To illustrate the operation of the invention, calorimetry experiments were performed with this apparatus using two different electrolytes 7.1, differing only in the inclusion of boron in one case and its omission in the other. The boron-free electrolyte 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 D2O. This procedure was carried out under a nitrogen atmosphere.

A calorimetry experiment was performed with this boron-free electrolyte 21 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 second experiment was performed using the same apparatus but with boric acid added to the electrolyte 21- The addition of the order of 0.2 millimoles of H3BO3 produced surface regions in the cathode that were loaded with boron to at least 10 atomic percent. This experiment was carried out over a total duration of 1287 hours. Excess heat was first observed after 658 hours of electrolysis and was observed on three separate occasions. The maximum excess power observed was 0.8 watts (300% in excess of the input power) ; the total excess of energy was 0.25 MJ, or 11 MJ/mole of Pd. In comparing the observations from these two experiments, it is found that the addition of boron to the electrolyte 21 coincided with the following effects:

1. The excess heat production was initiated spontaneously, rather than during a period of increasing current. 2. The initiation occurred at substantially lower current density than in the case where boron-free electrolyte was used.

3. Excess heat production terminated while the current was still at a high value. While the above description of the preferred embodiments discloses one technique for the inclusion of boron in the electrolyte 21r other methods could be utilized to achieve the loading of boron into the cathode 1. The cathode may be fabricated as a palladium-boron alloy before assembly into the cell 12., 62. Furthermore, other palladium alloys, such as Pd/Ag, having a similar FCC crystal structure can be used in place of pure palladium for loading with boron and deuterium.

Finally, the use of boron per se is not intended to be limiting, since other materials that occupy octahedral interstitial sites in the palladium lattice could accomplish the same result. For example, the alloy PdCn ir, contains carbon atoms on octahedral interstitial sites, as demonstrated experimentally using powder neutron diffraction [S. B. Siemecki, G. A. Jones, D. G. Swartzfager and R. L. Harlow, Journal of the American Chemical Society, Vol. 107, pp. 4547-4548 (1985)] . Therefore carbon is a good candidate to substitute for boron.

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 alloy surface, said deuterium accumulating within the cathode surface, wherein said alloy has regions that include boron in an atomic ratio of boron to palladium that is substantially greater than 0.028; 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 atomic ratio of boron to palladium in said alloy is at least 0.10.

4. Apparatus for producing heat, said apparatus comprising: an electrolyte comprising deuterium and conducting ions, wherein said conducting ions contain boron; 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 and said boron accumulating within the cathode surface; and current generating means coupled to said anode and said cathode for producing an electric current in said electrolyte.

5. Apparatus as recited in claim 4, wherein the current produced by said current generating means causes deuterium and boron to be loaded into said cathode.

6- Apparatus as recited in claim 4, wherein said boron is produced by dissolving a soluble compound containing boron in said electrolyte.

7. Apparatus as recited in claim 6, wherein said soluble compound comprises boric acid.

8. 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 alloy surface, said deuterium accumulating within the cathode surface, wherein said alloy is an interstitial alloy with a host lattice having a face centered cubic crystal structure and with solute atoms occupying octahedral sites within said host lattice; and current generating means coupled to said anode and said cathode for producing an electric current in said electrolyte.

9- Apparatus as recited in claim 8, wherein said solute atoms comprise boron.

10. Apparatus as recited in claim 8, wherein the atoms occupying said host lattice sites comprise a substitutional alloy of palladium.

11. Apparatus as recited in claim 10, wherein said substitutional alloy comprises palladium-silver.

12. Apparatus for producing heat, said apparatus comprising: an electrolyte comprising deuterium and conducting ions, wherein said conducting ions contain an elemental species that forms an interstitial alloy with palladium and resides on octahedral sites in said interstitial alloy; 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 and said elemental species accumulating within the cathode surface; and current generating means coupled to said anode and said cathode for producing an electric current in said electrolyte.

13. Apparatus as recited in claim 12, wherein said elemental species comprises boron.

14. Apparatus as recited in claim 12, wherein said elemental species comprises carbon.

15. Apparatus as recited in claim 12, wherein the current produced by said current generating means causes deuterium and said elemental species to be loaded into said cathode.