JP2002539595A - Metal sponge for rapid surface chemistry - Google Patents

Abstract

(57) Abstract: On the front (14) of the decorative vinyl wall covering (10), a protective coating (18) is made from a dry wipeable fluorocarbon polymer. The product can be used in the same way as conventional wallpaper or vinyl wall covering to obtain a decorative design that is rich in decorativeness that covers some or all of the walls in a room. However, since the marking made on the product can be easily removed, the decorative design with rich decorativeness can be written as desired.

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION The present invention relates to surface chemistry technology. This has particular application in conjunction with a reaction surface formed from a metal sponge having a high surface area that can be easily contacted to carry out a chemical reaction, and will be described with particular reference thereto. However, the present invention
It should also be appreciated that it is applicable to a variety of applications where the ratio of contactable high surface area to volume is advantageous. Many chemical reactions include surface reactions that occur on the surface of one or more reactants. For example, devices such as batteries, catalysts, gas sensors, fuel cells, and heat exchangers all rely on chemical reactions occurring at the surface. For such reactions, the rate of the reaction is highly dependent on the available surface with which the reactants can interact.

In order for such a device to have optimal efficiency, a reactant is supplied to the surface,
It is desirable that the resistance to take out the reaction product from the surface is small. For example, a battery containing an anode, an electrolyte, and a cathode would benefit from an anode having a high surface area that can be contacted where the oxidation reaction occurs at a high rate. Similarly, batteries benefit from a high surface area cathode that can be contacted for rapid reduction reactions. this is,
The result is a high output of the battery. Conventionally, a battery is made up of a number of alternating plates, providing an anode and a cathode. Below a certain thickness, the thickness of the plate is limited because the plate does not have sufficient rigidity to maintain the desired spacing.

[0003] Metal sponges offer the opportunity to increase surface area over conventional electrode materials.
Titanium sponges, such as those manufactured by the Hunter and Kroll methods,
It has a relatively large surface area. However, the surface area need not be maximized because the sponge is completely enclosed and a significant portion of the surface cannot be contacted. The present invention provides a new and improved reaction surface formed from sponge that overcomes the above-referenced problems and others.

According to one aspect of the present invention, there is provided a battery including an anode, a cathode, and an electrolyte therebetween. The battery features at least one anode and cathode comprising an electrically conductive sponge material. According to another aspect of the present invention, there is provided a method of performing a reaction on a surface. The method includes forming a surface, contacting the surface with a reactant, and causing a reaction. The method features forming a surface that includes growing a sponge material having a plurality of open pores that can contact a reactant. One advantage of the present invention is that a reaction surface having a large surface area per unit weight is formed, thereby allowing a reduction in device size. Another advantage of the present invention is that it provides multiple, short flow paths for efficient transfer of reactants and reaction products. Still further advantages of the present invention will be apparent to one of ordinary skill in the art upon reading and understanding the following detailed description of the preferred embodiments.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A large internal surface area reaction surface is made from metal sponge. The sponge is formed by directional growth of a dendritic sponge on a suitable substrate or non-directional growth of a sponge. The sponge of the present invention has a large specific surface area (surface area per unit volume). For dendrite sponges, ie sponges in which separated dendrites adhere to a common substrate or skeleton, the specific surface area is approximated by the general formula: specific surface area = (circumference of dendrite x volume of sponge material) / cross-sectional area of dendrite Can be calculated.

For example, a cylindrical dendrite sponge with a diameter of 100 nm is 40 m ² /
It has a specific surface area of cm ³ . As a comparison, 1 cm ³ of solid is about 0.0006 m ²
/ Cm ³ . The rate of a chemical reaction that occurs on a surface follows the formula: rate of reaction = reactant / volume x time. The finer the dendrite, the greater the surface area and the faster the reaction at the surface.

[0007] It is important, however, that this surface area be readily accessible to mobile reactants, such as electrolytes or reactant gases, and provide a path for reaction products to migrate from the surface. Thus, in order to provide low resistance to such movement, both the flow path provided by the pores between the dendrites and the conduction path through the dendrites themselves are preferably short. The short flow paths are: a) By imparting a directional structure to the sponge, the pores between the dendrites are arranged to be short flow paths, and the dendrites are also arranged to be short conductive paths. Or b) providing a non-directional sponge geometry in the form of a thin layer with multiple short flow paths for contacting the electrolyte and / or reactant.

For electrical applications, such as in batteries, this layer is preferably lined with a material of high electrical conductivity. The geometry of thin layers of directional and non-directional sponges to provide a highly accessible surface for rapid migration of mobile reagents and products, conduction of ions or electrons in the electrolyte Arrays are particularly suitable.

Materials suitable for sponges are aluminum, beryllium, carbon (graphite and other forms), cadmium, calcium, cesium, chromium, copper, germanium,
Includes gold, iron, lead, lithium, magnesium, manganese, nickel, niobium, platinum, potassium, sodium, silicon, silver, tantalum, titanium, vanadium, zinc, zirconium, or alloys of these metals. The choice of material depends on the type of reaction in which the reaction substrate is used. For electrical applications such as batteries, the sponge material is electrically conductive. For a catalyst, the sponge material is preferably one capable of catalyzing the reaction.

[0010] The reaction surface can be formed in a number of ways, as described in detail below. It may be formed entirely from sponge material, as in the case of extruded dendrite sponges formed by a solidification method. Alternatively, the reaction surface may comprise a substrate material on which the sponge is grown or deposited by sintering or other suitable method. This sintering method can also be used for directional sponges, but is particularly suitable for forming a reactive surface from non-directional sponge particles. For some applications, the sponge may be coated on its surface with a layer of a different material. For example, for use in catalysts, the sponge may be formed from an economical base material and coated with a thin layer of catalytic material to create a high surface area catalyst.

This reactive surface has applications in a wide variety of devices, including catalysts, fuel cells, gas sensors, heat exchangers, and electrode materials for batteries. All of these applications have the advantage of having a large surface area and ease of surface contact, derived from relatively short paths or pores. Reaction surfaces using two types of sponges, directional and non-directional, are described in further detail. It should be appreciated that both sponge types are suitable for other applications, such as catalysts, fuel cells, etc., but by way of example the use of the reaction surface as an electrode in a cell is shown.

Reaction surface using directionally grown sponge Reaction surface using directionally grown, dendritic sponge has a large contact surface area and a short flow path. The dendrite is preferably very fine, preferably having a width of about 30 micrometers or less, and more preferably 1 micrometer or less, up to several nanometers. The ultrafine dendrite structure has a high surface area (a few hundreds) where a chemical reaction occurs.
m ² / cm ³ ). The gaps or pores between the dendrites preferably have a pore size of 30 micrometers or less, more preferably 300 nm or less.

The dendrite grows directionally on the substrate. The substrate is a ribbon, wire,
In the form of a cast structure or sheet. Alternatively, the substrate may be extruded along a dendrite. This substrate provides a sponge with structural stability and, if desired, electrical conductivity. The substrate may be formed from the same material as the sponge, or from a different material. Silver, copper or aluminum substrates are preferred for applications requiring electrical conductivity.

[0014] One preferred form of the reaction surface including the dendrite sponge is an anode or cathode material in a battery. Referring to FIG. 1, a battery 1 includes an anode 10 and a cathode 12 using a reaction surface. In particular, the anode and cathode are formed from interdigitated sheets of foil 14 having a thickness of about 10 μm or more. This foil acts as a skeleton or substrate for the dendrite sponge material 16. The sponge material includes a number of dendrites 18 extending from the substrate surface.

[0015] An electrolyte 20 surrounds the anode and cathode. Casing 22 provides an outer cover for the battery. In some cases, this cathode acts as a casing. Conductor leads 30 and 32 are connected to the anode and cathode of an electric circuit (using a battery).
(Not shown). While FIG. 1 shows both anode 10 and cathode 12 as including a dendritic sponge, it should be appreciated that either an anode or a cathode can be formed without a dendritic sponge.

As long as the foil sheets are reasonably close together, preferably less than a few centimeters apart, this electrolyte has a low resistance and is sufficient for the cell to have a very high power density. Equivalent series resistance of the battery (R) (ESR) is obtained by the equation _{R = R AE + R CE +} R E + R A + R C. _Where R _AE is the ESR of the chemical reaction between the anode and the electrolyte, R _CE is the ESR of the chemical reaction between the cathode and the electrolyte, R _E is the resistance of the electrolyte, and R _A is the resistance of the anode. And _RC is the cathode resistance. R _AE , R _CE and R _E all depend on the surface area. R _AE is inversely proportional to the surface area of the anode / electrolyte interface, or the surface area of the anode. R _CE is inversely proportional to the cathode surface area. During R _E = ρA _P / t formula, [rho is the resistivity of the electrolyte, A _P is the projection surface area of the substrate, and t is the width of the electrolyte layer, that is, the anode and cathode spacing. The anode and cathode resistances are usually small when compared to other resistances and are therefore negligible.

FIGS. 2, 3, and 4 show various configurations of the dendrite 18. On the preferred reaction surface 36, the dendrite is preferably perpendicular or nearly perpendicular to the substrate 14 to minimize electrical resistance. There are open pores 37 between the dendrites, which, in the case of batteries, bring into contact with reactants such as electrically charged species,
In the case of a catalyst surface, contact is made with a reagent that undergoes a catalytic reaction on the surface. As shown in FIG. 3, the dendrite may have small or secondary dendrites 38, which in turn grow from the surface to further increase the surface area per unit substrate area. Directional grown dendrites have a large ratio of length to width and are dense and relatively evenly spaced to maximize surface area. As shown in FIG. 2, the dendrite may be coated with a thin layer of surface material 39b that provides improved electrical conductivity. Alternatively, the surface material may provide a reaction surface 36 that acts as a catalyst in applications where the reaction surface catalyzes the reaction.

This directional grown dendrite provides a large surface to volume ratio and good surface contact. This contact is important for the electrical properties and for the movement of the reactants and reaction products, in that the conduction paths formed are relatively short and tend to be parallel. This contact also improves sponge purification in that unwanted material is easily removed from the gaps between the dendrites. For electrical devices, this contact allows the electrolyte to penetrate the sponge and completely fill the sponge.

This reaction surface (36) is very suitable for use in catalytic reactions. A catalyst is a substance that increases the rate of a chemical reaction. The reagent is usually in gaseous or vapor or liquid form. The use of the present invention relates to such a reaction in the presence of a solid catalyst. The fact that the catalyst has a high surface area and that this surface area can be easily contacted with the reactants has the advantage of accelerating the chemical reaction. Non-directional sponges may also be used, but these desired conditions are best met by directional dendritic sponges as shown in FIGS. The sponge is the catalyst itself or a carrier for the catalytic material attached to the sponge surface. The desired conditions for accelerating the reaction are also satisfied by a sponge with easily accessible pores and a thin layer of sponge that allows the reactant to flow through the open-ended pores with little resistance. The pores of the directional or non-directional sponge layer are preferably relatively direct and have an open path. The sponge layer may be on a substrate such as a wire, foil, ribbon or other prepared shape, or may be freestanding. The pores are open ends towards at least one side of the layer or open ends through the thickness of the layer. Sponge made by the methods described herein generally have these desired properties. Therefore, these
Particularly suitable for functioning as a catalyst or as a carrier for a catalyst. Suitable metals for the catalyst sponge material or surface catalyst layer 39 are Li
, Be, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co,
Ni, Cu, Zn, Ge, Sr, Y, Zr, Nb, Mo, Rh, Pd, Ag. C
d, In, Sn, Sb, Te, Ba, La, Ce, Pr, Nd, Pm, Sm, E
u, Gd, Tb, Dy, Ho, Er. Tm, Yb, Lu, Hf, Ta, W, Rh
, Os, Ir, Pt, Au, Ti, Pb, Bi, Po, and combinations thereof.

Formation of Dendrite Sponge To form a directional sponge, a dendrite is directionally grown on a substrate material. Several methods can be used to form dendritic sponges. Three methods have been found to produce particularly uniform dendrites of high surface area. In the first of the chemical methods, the metal halide in vapor form is reduced by a reducing agent, preferably an alkali metal or alkaline earth metal, and dendrites of the reduced metal are deposited on the substrate material.

The metal halide is a gas at the reaction temperature. Some metal halides have been found to be suitable. These include chloride, fluoride, and iodide of titanium, aluminum, tantalum, niobium, zirconium, vanadium, chromium, silicon, germanium, and mixtures thereof. For example, for a titanium sponge formed by the reduction of titanium chloride with magnesium, the deposition process is described by the following formula: TiCl ₄ (g) + 2Mg → Ti (s) + 2MgCl ₂ liquid or vapor liquid or solid. The reaction products are solid titanium and magnesium chloride and may be liquid or solid, depending on the temperature used.

Due to the coexistence of the two reaction products, in the case of titanium metal and magnesium chloride, the morphology of the growing sponge consists of titanium dendrites with magnesium chloride present in the gaps between dendrites. Magnesium chloride or other alkali metal halide is removed by drainage and vacuum distillation or by leaching. The vacuum distillation ensures that any remaining traces of magnesium chloride are removed so as not to contaminate the sponge. Preferably, the distillation is performed at a high vacuum between 800 and 1200 ° C. to ensure complete removal of the alkali metal halide. Magnesium and sodium are particularly preferred reducing agents, with sodium being most preferred because of the easier removal of sodium chloride. In addition, the use of sodium as a reducing agent allows for the selection of sponge roughness or fineness levels. Extremely fine sponges can be produced at relatively low temperatures (600-700 ° C.).

A mixed sponge may be formed by this method. For example, TiCl ₄ and ZrC
A mixture of l ₄ by reducing the alkali elements (A) or alkaline earth (EA) element, may be formed Ti-Zr alloy sponge. This sponge synthesis process proceeds by the reaction (TiCl ₄ + ZrCl ₄ ) + (A or EA) → (Ti + Zr) + (A or EA) -chloride gas mixture liquid or gas solid alloy sponge solid or liquid salt. A specific example of forming a sponge of 50 atomic% Ti and 50 atomic% Zr alloy using potassium as a reducing element is (TiCl ₄ + ZrCl ₄ ) + (8K) → (Ti + Zr) + (8KCl) gas Mixture Liquid or gas Solid alloy sponge Solid or liquid salt.

FIGS. 5 and 6 illustrate a process for depositing dendrite 18 on substrate 14. This process is described with particular reference to the formation of titanium sponges by reducing titanium chloride with sodium. However, this process
It should be appreciated that it is also suitable for forming other metal sponges with different reducing agents. Depending on the reducing metal vapor pressure and other reaction variables, this process condition will vary. A reaction vessel 40 for performing the sponge forming process defines a chamber 42. This substrate 14 is supported in chamber 40 by electrically conductive connectors 44 and 46. To heat the substrate to a suitable reaction temperature, a power supply 50 is connected by a connector. A storage container 5 in the chamber to provide the vapor pressure of the reducing agent in the chamber.
2 contains sodium or other reducing metals. The generated steam pressure depends on the temperature of the chamber. For example, at 520 ° C., the vapor pressure of sodium is 10 ⁻² atm. A heating source 54 surrounds the chamber to heat the chamber to a suitable temperature and provide steam.

First, the heating source 54 is turned on, and the chamber is brought to a desired temperature in order to evaporate the reducing agent. A preferred chamber temperature is 705 ° C., although other temperatures can be used for the sodium reducing agent. Next, the power supply 50 is turned on, and the base material 1
4 is resistance heated to the selected deposition temperature. Usually, the deposition temperature is higher than the temperature of the chamber, so that the deposition of titanium occurs mainly on the substrate. The heated substrate provides a limited number of nucleation sites for dendrite growth. Once the desired chamber and substrate temperatures have been reached, a halide source of sponge material 60, such as a titanium chloride source, supplies titanium chloride to chamber 42 through inlet 62.
An inlet valve 64 between source 60 and inlet 62 allows the rate of introduction of titanium chloride to be adjusted. At the temperature and pressure of the chamber, titanium chloride is in the form of a vapor and is reduced by sodium on the heated substrate surface. Outward directional dendrite sponges of titanium dendrites are formed in the interdendrites with sodium chloride. The exact microstructure of the sponge depends on the number of nucleation sites on the substrate and the processing parameters, i.e., the sodium vapor pressure, _PNa , titanium chloride vapor pressure, _PTiCl4 and reaction temperature.

A chamber temperature of 100-1,000 ° C. is suitable for forming a titanium sponge in this method. A particularly preferred temperature is 800 ° C. or less. The growth rate and shape of dendrite are temperature dependent. At low temperatures, dendrites are fine and have a large surface area. However, the growth rate is relatively slow. At higher temperatures, growth is faster, but dendrites are wider and have a smaller surface to volume ratio. Thus, the surface area of the sponge can be selected according to the desired properties of the reaction surface. Once suitable growth of the sponge has been obtained, unwanted reaction products, in this case sodium chloride, are removed by vacuum distillation as shown in FIG. A vacuum pump valve or outlet valve 66 connects to a vacuum source (not shown), such as a pump, at the outlet of the reaction vessel. The inlet valve 64 is closed to stop the supply of titanium chloride into the chamber 42 and the source of sodium 52 is preferably sealed or removed from the chamber to prevent unnecessary waste of sodium. Open the vacuum pump valve 66,
Adjust the temperature of the chamber to a suitable distillation temperature. The vacuum pump draws sodium chloride through gaps in the sponge and from the chamber. Due to the regular orientation of the dendrites, the removal of sodium chloride takes place from essentially all surfaces of the sponge. No enclosed pores trapping sodium chloride are formed.

The time required for distillation depends on the temperature and on the length and width of the gas diffusion path from the interdendritic region. The vapor pressure of sodium chloride in the atmosphere is given by the following equation: log (P _NaCl ) = − 12,440 T ⁻¹ −0.90 log T−0.46 × 10 ⁻³ T + 1
1.43. Where T is the temperature in degrees Kelvin. The vapor pressure of sodium chloride ranges from 4 × 10 ^-5 to 1.9 × 10 ^-2 atm in the temperature range from 800 to 1,000 degrees. Thus, complete removal of sodium chloride by vacuum distillation is easily performed. The second process for forming dendrite sponge is a solidification method. In this method, a sponge is deposited from a mixed liquid by heating the sponge material together with the insoluble material to a temperature at which both the sponge material and the insoluble material are liquid. Upon solidification, a heterogeneous solid is obtained. This method is particularly suitable for forming aluminum sponges. Table 1 lists the combinations of materials for forming the sponge. This insoluble material is insoluble in the selected sponge material. It may be an element or a salt.

[0028]

[Table 1]

The heated mixture of mutually insoluble materials is cooled. It may be exposed to freezing temperatures to speed up rate setting. This mixture solidifies with the dendrite structure, such that the solid part consists of sponge material and the gaps between dendrites consist of insoluble material. The higher the cooling rate, the finer the dendrite structure and the larger the sponge surface area per unit substrate area. For example, a mixture of aluminum and potassium solidifies as an aluminum dendrite structure, with gaps between dendrites consisting of potassium. For example, the potassium can be removed by vacuum distillation leaving an aluminum dendrite skeleton.

The sponge grown by the solidification method may be grown as a directionally solidified dendrite on a prepared substrate 82 as shown in FIGS. 7A, 7B and 7C, or as shown in FIGS. 8 and 9. Alternatively, it may be extruded as a ribbon. By providing a temperature gradient that is cooler than the dendrite on which the substrate grows, the direction of solidification can be further enhanced. In the embodiment of FIG. 7, a cold metal substrate 82 is immersed in a well-mixed molten mixture 84 of a liquid sponge material 86 and a liquid insoluble material 88. As can be seen in FIGS. 7B and C, the dendrites of sponge material 86 grow on the substrate in a direction generally perpendicular to the substrate surface. Insoluble material 88 is excluded in the gap between the dendrites.

In the configurations of FIGS. 8, 9, and 10, a molten mixture of sponge material and insoluble material is contacted with a rotating heat sink. As shown in FIG. 8, the mixture 90 flows from a narrow opening 94 onto a rotating cylindrical heat sink 96 such as a roller disposed below the mixture, which is heated by a heating coil 92. As the heat sink rotates, a ribbon 98 of solidified sponge material is formed. As shown in the enlarged cross-section of FIG. 9, the dendrite 100 in the ribbon comprises a continuous layer 102 of sponge material closest to the heat sink.
At the same time, it grows outward from the side closest to the heat sink. Layer 102 acts as a substrate for supporting dendrites. As before, the insoluble material 104 is removed from the interdendritic space by vacuum distillation.

In the embodiment of FIG. 10, a rotating cylindrical heat sink 108 contacts a bath 110 of a mixture 112 of a sponge material 114 and an insoluble material 116. In some cases, the stirrer 118 in the bath continues to provide good agitation of the sponge material and the insoluble material. As the heat sink rotates, the layer of the mixture adjacent to the sink cools and the ribbon 1
20 are formed. As in the case of the configurations of FIGS. 8 and 9, the dendrites of sponge material 114 grow outward from the surface of the heat sink and the insoluble material concentrates in the interstices between the dendrites. For the consolidation method, the sponge material has a melting point that is preferably about 1,700 ° C or less, more preferably 1200 ° C or less, to facilitate processing.
In some cases, the sponge material may be an alloy of one or more of the following elements. Mg, Al, Si, Zn, Ga, Ge, Be, Li, Ni, A
u, Pt, Cu, Ag, As, Se, Cd, In, Sn, Sb, Tl, Pb, B
i and rare earth elements.

A third method for forming dendrite sponge is an oxidation / reduction method.
In the first step, an oxide scale is grown on a suitable substrate. Referring to FIGS. 11A, 11B, 11C, and 11D, the substrate 120 may be a sheet, piece, wire, mesh, or metal such as Ti, Ta, or an alloy of Ti-Ta, Ti-Zr, or Ti-Be. It may be in the form of a processed skelton. The thickness of the scale 122 is preferably between 0.5 micrometers and 10 millimeters. This metal has an oxide of one or more Pilling-Bedworth ratio. In this case, the molecular volume moles of the resulting oxide scale 122 are larger than the volume of metal 124 consumed (compare FIGS. 11B and 11A). For example, for tantalum having a Pilling-Bedworth ratio of 2.5, this oxide layer is at least 2.5 times the thickness of the metal consumed. The scale may be grown to such an extent that all or only a portion of the substrate is converted to oxide scale. The thickness of this scale is preferably 1 to 10 ⁴ times the desired pore size of the metal sponge to be formed.

In a second step, shown in FIGS. 11C and 11D, the oxide scale is reduced to metal 126 at a high temperature with a suitable reducing agent 128. Metal Ti, Ta, Zr,
For Be or oxides of these alloys, Li, Mg, Ca, Ba, Sr
And reducing agents such as hydrogen are effective. Reducing agent 128 is preferably in gaseous or liquid form. For example, tantalum oxide scale may be reduced to tantalum sponge in the presence of hydrogen as follows. Ta ₂ O ₅ + 5H ₂ → 2Ta + 5H ₂ O Oxide scale Reducing agent Sponge layer Reducing agent oxide Similarly, titanium oxide scale may be reduced to titanium sponge with calcium as follows.

Tio ₂ + 2Ca (Liquid or Vapor) → Ti + 2CaO Oxide Scale Reducing Agent Sponge Layer Oxidation of Reducing Agent Reduced metal is porous because it has a smaller volume than that of oxide scale . Thus, during the reduction reaction, this oxide layer is a metal sponge with generally directional pores 130, shown in FIGS. 11C and 11D, extending from the outside of the reduced metal toward the substrate / reduced metal interface. Is transformed into These pores contain an oxide of the reducing agent, for example water vapor for hydrogen and calcium oxide for calcium. This oxide may be leached with, for example, water or an acid such as acetic acid. In the case of water as oxide, this water may be carried away, preferably as steam. The remaining metal sponge has many of the properties of the outwardly grown sponge produced by the first and second methods. This sponge has a high surface area of open pores that can be easily contacted.

If only a portion of this substrate is converted to oxide scale and then to metal sponge, the remaining substrate provides a path of high electrical conductivity. Thus, the substrate supplies and receives the dendrite and current. High electrical conductivity paths are important for batteries and other electrical applications.

Reaction Surface Using Non-Directionally Grown Sponge A non-directionally grown sponge is a sponge in which pores are oriented in random directions and are directional within certain grains. As in the case of a directional sponge, the pore width is chosen according to the application, for example, the desired power density or the reaction product formed.
Preferably, the pores consist of interconnected channels having a width of about 10 nm to 100 μm or more. Several methods exist for forming a reactive surface. In a first method, a thin layer of sponge particles is bonded to a substrate, such as a piece of metal. The layer of sponge particles is preferably less than 2 cm thick and may be as thin as 1 μm or less. In a second method, a non-directional sponge is grown on a substrate.

In one preferred form, the reaction surface is used as a battery electrode. FIG.
The battery 1 in which the anode 140 (reactive surface), which has a surface layer of electrically conductive metal sponge particles 144 sintered or bonded by other suitable methods, includes a metal piece 142,
38 is shown. The battery also includes a cathode 14 forming the outer casing of the battery.
6 and an electrolyte 148 that penetrates the pores of the sponge particles and contacts the large surface provided by the sponge for an electrochemical reaction. Insulating material beads 150
The terminal 152 is separated from the adjacent cathode with respect to the anode. Obviously, both the anode and the cathode, or only one of the electrodes, may be formed from sponge particles. If both are formed from sponge particles, the sponge particles may be formed from the same or different materials.

FIGS. 13-14 show different forms of a battery in which the electrodes comprise interdigitated metal strips. In the embodiment of FIG. 13, the battery 158 includes an anode 160 having a series of conductive metal pieces 162. The sponge particles 164 are sintered in the form of a thin layer 166 of the particles on the upper and lower surfaces of the strip. Cathode 168 includes metal strip 170 without sponge particles. In the configuration of FIG. 14, a battery 18 in which both anode 182 and cathode 184 include metal strips 186, 188 with sintered sponge particles 190, 192, respectively.
0 is formed. The anode and cathode sponge particles are preferably formed from different materials.

FIG. 15 shows a battery 200 including a non-directional sponge surface layer 204 in which the anode 202 has been formed on a substrate material 206 by a scale growth and reduction method. Cathode 208 may be formed in the same manner or, as shown in FIG.
10 may be included. Other combinations for the anode and cathode are also contemplated. For example, one of the anode and cathode may be formed from a non-directional sponge and the other may be formed from a directional sponge. The electrodes may be formed from sponges having different porosity, or may be formed from different materials. The sponges may be formed by the same or different methods.

Formation of Non-Directional Sponge With respect to the directional sponge, a number of methods can be used to form the non-directional sponge. In the first method, a slightly modified chemical vapor deposition is used, as described for the directional sponge. Specifically, the metal halide in the form of a vapor is reduced by a reducing agent, preferably an alkali metal or alkaline earth metal. The reduced metal sponge grows non-directionally in the reaction chamber. This is achieved by removing the substrate material at all or depositing the sponge on the substrate material without controlling the direction of dendrite growth. Undesired reaction products, such as sodium chloride, as in the case of directionally grown sponges,
Leaching is by vacuum distillation as shown in FIG. 6, or by any other suitable method.

In a second method, the sponge is grown by a solidification method in a manner similar to that described for the directionally grown sponge. However, in this case, this sponge produced by a solidification method in which there is no guide during the solidification process grows as a random sponge. The two insoluble materials are cooled without the presence of the substrate, and a non-directional sponge is formed with unwanted reaction products in the pores of the sponge.
Next, unwanted reaction products are removed as in the case of a directional sponge. However, because the insoluble interdendritic material is easily removed, the area that cannot be contacted is small, the electrolyte or the reagent is easily infiltrated, and the internal resistance is low, the directionally solidified sponge is less than the non-directional sponge. preferable.

In a third method, the oxide particles are reduced to a sponge material,
Alternatively, sponge particles are formed by reducing a layer of oxide grains.
This is similar to the scale reduction method shown in FIG. However, this
The grains may consist of loosely bound or sintered oxide particles. An example
For example, a base material such as iron, nickel, or tin is mixed with a binder material and iron oxide or nickel oxide.
Coating with a slurry formed from nickel oxide or oxide particles such as titanium oxide.
You. The coated substrate is heated to remove the binder material. Next, this surface is H _Two Reduction with a suitable reducing agent such as, CO, or Ca. This allows this surface
Sintered or loosely bonded layers of metal sponge particles (non-directional). The non-directional sponge particles are then sintered or otherwise suitable by other suitable methods of attachment.
To a suitable base material.

[Brief description of the drawings]

The invention may take form in various components and arrangements of components, and in various steps and arrangements of steps. This drawing is for the purpose of illustrating preferred embodiments only and should not be considered as limiting the invention.

FIG. 1 is a side cross-sectional view of a battery containing a directionally grown sponge material according to a first embodiment of the present invention.

FIG. 2 is a schematic view of the substrate and dendrite of FIG.

FIG. 3 is a schematic diagram of an alternative form of the substrate and dendrite of FIG.

FIG. 4 is a perspective view of the substrate and the dendrite of FIG. 1;

FIG. 5 is a schematic diagram of a system for chemically forming a directionally grown sponge of the present invention.

FIG. 6 is a schematic diagram of the system of FIG. 5 during the distillation phase.

FIG. 7 is a schematic side view showing the progressive growth of a directional sponge by a solidification method.

FIG. 8 is a schematic diagram of a ribbon extrusion system showing the solidification method and dendrite sponge growth by ribbon extrusion.

FIG. 9 is a schematic diagram of a ribbon extrusion system showing the solidification method and the growth of dendritic sponges by ribbon extrusion.

FIG. 10 is a schematic side view showing an alternative form of the ribbon extrusion system.

11: A) before oxidation, B) after oxidation, C) after partial reduction of this oxide film.
And D) Schematic of the metal substrate after complete reduction.

FIG. 12 is a side cross-sectional view of a battery containing a non-directional sponge material of the second embodiment of the present invention.

FIG. 13 is a side sectional view of a battery containing a non-directional sponge material according to a third embodiment of the present invention.

FIG. 14 is a side cross-sectional view of a battery containing a non-directional sponge material according to a fourth embodiment of the present invention.

FIG. 15 is a side sectional view of a battery containing a non-directional sponge material according to a fifth embodiment of the present invention.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01M 4/64 H01M 4/64 A 4/66 4/66 A (81) Designated countries EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE), OA (BF, BJ, CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, GM, KE, LS, MW, SD, SL, SZ, TZ, UG, ZW), EA (AM, AZ, BY) , KG, KZ, MD, RU, TJ, TM), AE, AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, CA, CH, CN, CR, CU, CZ, D , DK, DM, DZ, EE, ES, FI, GB, GD, GE, GH, GM, HR, HU, ID, IL, IN, IS, JP, KE, KG, KP, KR, KZ, LC, LK, LR, LS, LT, LU, LV, MA, MD, MG, MK, MN, MW, MX, NO, NZ, PL, PT, RO, RU, SD, SE, SG, SI, SK, SL , TJ, TM, TR, TT, TZ, UA, UG, US, UZ, VN, YU, ZA, ZW (72) Inventor McGarvey, Donald United States, 44118 Cleveland Heights, Wilton Road, Ohio 1819 (72) Inventor Suzodoski, Paul 44119 Ohio, United States, Euclid, Mirror Avenue 21600 F-term (reference) 4K001 AA01 AA02 AA04 AA05 AA06 AA07 AA08 AA09 AA10 AA12 AA13 AA15 AA16 AA17 AA18 AA19 AA21 A23 AA24 AA25 AA26 AA27 AA28 AA29 AA30 AA31 AA34 AA36 AA37 AA39 AA41 BA08 DA11 EA01 EA02 EA05 5H017 BB01 BB10 BB13 BB16 BB17 CC01 CC18 CC25 CC25 EE00 EE05 EE08 HH04 HH05 HH08

Claims (28)

[Claims] 1. An anode (10, 140, 160, 182, 202), a cathode (12, 146, 168, 184, 208) and an electrolyte (20,
148), wherein at least one anode (10, 140, 160, 182, 202) and cathode (12, 184, 208) are electrically conductive sponges. Material (16,114,1
64, 204). 2. An electrically conductive substrate (14, 82, 102, 1) wherein said at least one anode and cathode are in electrical contact with an electrically conductive sponge material.
20, 142, 162, 186, 188, 206). 3. The substrate comprises a foil (14), a wire, a ribbon (98, 102, 1).
20) The battery of claim 2, further in the form of a cast structure or sheet (14,82). 4. The battery according to claim 2, wherein said substrate and said electrically conductive sponge are formed from the same material. 5. The battery according to claim 2, wherein the substrate further comprises a metal selected from the group consisting of silver, copper, and aluminum. 6. The particles (144, 164, 164) having the sponge material adhered to a substrate.
190, 192), wherein the battery according to any one of the preceding claims, further characterized in that: 7. A method according to claim 2, wherein the sponge material is in the form of a layer of sponge grown on a substrate. 6. The battery according to claim 5. 8. The at least one anode (10, 160, 182, 2)
8. The method as claimed in claim 1, wherein the cathode and the cathode further comprise a plurality of thin layers of electrically conductive sponge material. Batteries. 9. The electrical conductive sponge material of claim 1, further comprising an element selected from the group consisting of copper, silver, gold, aluminum, and combinations thereof. The battery according to claim 1. 10. The electrically conductive sponge material comprises dendrite (18,1).
00). The battery according to any one of the preceding claims, further characterized in that: 11. The battery of claim 10, wherein said dendrite has a width of about 200 nanometers to 30 micrometers. 12. The at least one anode and cathode comprising at least one substrate layer (14, 82, 206) and a dendrite (18, 100).
12. The battery according to any one of claims 10 and 11, further comprising extending from the substrate. 13. The battery of claim 12, wherein the dendrite (18) extends substantially perpendicularly from the substrate layer (14). 14. The battery according to claim 1, wherein the sponge material is coated with an electrically conductive material (39). 15. A method wherein the reaction is carried out on a surface, said method comprising:
6), contacting the surface with the reagent and causing the reaction to occur, wherein the step of forming the surface comprises a plurality of open pores (37) capable of contacting the reagent.
, 130) with growing sponge material (16, 114, 164, 204). 16. The sponge material is composed of Li, Be, Mg, Al, Si, Ca.
, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ge, Sr,
V, Zr, Nb, Mo, Rh, Pd, Ag, Cd, In, Sn, Sb, Te, B
a, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, E
r, Tm, Yb, Lu, Hf, Ta, W, Rh, Os, Ir, Pt, Au, Tl
16. The method of claim 15, further comprising one of the group consisting of: Pb, Bi, Po, and combinations thereof. 17. The step of growing the sponge reduces the compound (122) to its elemental form (126), the elemental form taking up less volume than the compound and forming open pores. Claims 15 and 1 further comprising:
7. The method according to claim 6. 18. The step of growing the sponge includes heating the substrate (14) to a deposition temperature and contacting the substrate in the presence of an alkali metal or alkaline earth metal vapor with a vapor containing a halide of the sponge material. The sponge halide vapor reacts with the alkali metal or alkaline earth metal vapor to form an alkali metal vapor sponge material and an alkali metal or alkaline earth metal halide, and the sponge material is dendritic on the substrate (18). 18. The method of claim 17, further comprising depositing in the form: 19. The method according to claim 18, further comprising removing alkali metal or alkaline earth metal halide from the sponge material by vacuum distillation. 20. The step of growing the sponge comprises the step of growing the sponge material to a temperature at which the sponge material and the insoluble material are both liquid and the sponge material and the insoluble material are mutually insoluble at a temperature at which the sponge material freezes. 86, 114) with the insoluble material (88, 116), mixing the two liquids, cooling the sponge material and the insoluble material to form a sponge, and removing the insoluble material from the sponge. The method of claim 15, further comprising: 21. The cooling step comprises the steps of sponge material (86) and substrate (82).
21. The method of claim 20, further comprising cooling the insoluble material (88) adjacent to) to form a directionally grown sponge of the sponge material on the substrate. 22. The sponge material is made of Mg, Al, Si, Zn, Ga, Ge.
, As, Se, Cd, In, Sn, Sb, Cv, Ag, Ti, Te, Tl, Pb
22. The method according to any one of claims 20 and 21, further comprising an element selected from the group consisting of Bi, Bi, and alloys thereof. 23. The insoluble substance is Na, K, Rb, Cs, Ca, Sr, Ba.
22. The method of claim 21, further selected from the group consisting of: and salts thereof. 24. The step of growing the sponge forms an oxide scale (122) on the substrate (120), which substrate oxidizes at least an outer portion (124) of the substrate, Including a metal that is oxidizable to an oxide having a lower density than the substrate by forming an oxide scale, and including reducing the oxide scale to a metal, the metal having an open pore structure The method of claim 17, further comprising: 25. The reducing step wherein the reducing step comprises reducing the oxide with a reducing agent (128), and the method further comprises removing the reducing agent oxide from the pore metal after the reducing step. The method of claim 23, further comprising: 26. The method according to claim 24, wherein the oxide of the reducing agent is a fluid. 27. A metal sponge having a high specific surface area that has a reaction path not more than twice the thickness of a sponge and can contact a reaction reagent. 28. A metal sponge with an open pore structure between dendrites having an electrical resistance at least twice as low as that of a normal sintered powder sponge and allowing the flow of gas or liquid.