JPS5932869B2 - chemical battery - Google Patents

Description

[Detailed description of the invention] The present invention relates to chemical batteries.

Recently, there has been increasing interest in advances in energy storage mechanisms.

However, it is difficult to effectively immobilize the electrode active material that easily moves within the battery, that is, the electrochemically active electrode material, and to separate and control the electrode material well. Progress is not always enough.

Electrochemically active and mobile active materials can be made electrochemically active and mobile by using a compound of electrochemically active materials to immobilize them, or by using a solid electrolyte to function as an electrode separator. The problems in trying to retain materials efficiently have not been completely solved.
In this specification, the term "electrochemically active substance or electrode material" refers to an electrode active material that undergoes an electrochemical reaction in the presence of an electrolyte, and in the battery electrode of the present invention, pores of 100 angstroms or less are used. The electrochemically active electrode material sorbed and retained by the zeolite having a large number of zeolites consists of the following elements, alloys, compositions, or mixtures.

That is, the electrode material includes (a) halogen, alkali metal, alkaline earth metal, first and second series transition elements,
a composition containing at least one element selected from the group consisting of lead, phosphorus, arsenic, antimony, bismuth, and aluminum; (b) oxygen, sulfur, or selenium; or (c) carbon, boron, silicon, or nitrogen; A composition comprising a substance selected from the substances (a) and (b) above.

However, the above excludes the element or simple substance of sulfur and the element or simple substance of selenium. Here, excluding simple sulfur and simple selenium means not only pure sulfur or simple selenium, but also negative stabilizing elements such as selenium, arsenic, phosphorus, and antimony to lower the vapor pressure of sulfur. Sulfur contains a small amount of sulfur compared to sulfur, and selenium contains a small amount of stabilizing negative elements such as sulfur, arsenic, phosphorus, and antimony to lower the vapor pressure of selenium. Indicates to exclude. In one embodiment of the present invention, the electrode formed by sorbing or adsorbing the electrode material on zeolite has the form of an anode or negative electrode of an electrochemical cell, that is, a chemical cell.

In this case, the electrochemically active negative electrode material or negative electrode active material includes, for example, an alkali metal, an alkali metal combination, an alkaline earth metal, an alkaline earth metal combination, an alkali metal and/or an alkaline earth metal. Consists of positive substances including alloys or compositions. If the positive substance is an alkali metal, any alkali metal may be used, but lithium,
Sodium or potassium is preferred.

If the positive substance is a combination of alkali metals, any combination of two types of alkali metals may be used.

When the positive substance is composed of an alkaline earth metal, it is preferably calcium or magnesium, for example.

If the positive substance consists of a combination of alkaline earth metals,
A combination of two or more alkaline earth metals may be used.

When the positive substance is an alloy of an alkali metal and an alkaline earth metal, it may be an alloy containing one or more alkaline earth metals and one or more alkali metals in a desired ratio.

If the positive substance is an alloy or composition containing an alkali metal and/or an alkaline earth metal, one or more alkali metals and/or alkaline earth metals are included in this alloy or composition; The remaining components of the alloy or composition consist of compatible metals or similar materials that can form suitable alloys or compositions with the alkali metals and/or alkaline earth metals.

Similar substances here refer to, for example, silicon or aluminum. In addition, when this remaining component is a metal, this metal consists of aluminum, for example. The mass of the negative electrode is often an issue, and in this case it is desirable that the remaining components consist of a lightweight metal or material such as aluminum or silicon. From a practical, practical, and economic point of view, alkali metals and alkaline earth metals such as rubinidium, cesium, strontium, barium, and beryllium, due to their cost and rarity, is undesirable due to its toxicity, and in the case of the above-mentioned substances other than beryllium because of its The electrode may take the form of the cathode or positive electrode of the battery.

In this case, the electrochemically active cathode material or cathode active material consists of a negative substance consisting of, for example, a halogen, a mixture of halogens, or an interhalogen compound. In this case, the negative substance is, for example, fluorine, chlorine, bromine, or iodine, or a mixture of two or more of these halogens. or BrCl,
As for ICt, IBr, etc. Refers to interhalogen compounds.
When the electrochemically active electrode material to be sorbed or adsorbed on the zeolite consists of or contains one or more of the reduction elements, this electrode material contains transition elements of the first or second series. or an alloy containing a transition element,
It is in the form of a composition, mixture, or compound.

In this case, the electrode material may consist of or contain halides, sulfides, and selenide mold oxides of certain reducing elements. In addition, from the viewpoint of small mass, transition elements belonging to the first series (Sc to Cu) are more desirable than those belonging to the second series (Y to Af), and preferably one or more of the transition elements belong to the first series (from Y to Af). A series of transition elements is selected. With the exception of silver belonging to the second series, from the viewpoint of cost and availability, it is preferable to use a transition element of the first series rather than a transition element of the second series. In certain embodiments of the present invention, the electrode materials sorbed or adsorbed onto the zeolite include Cr, Fe, M
n, Tiy. consists of or includes V. An electrode made by sorbing or adsorbing this electrode material onto zeolite can be used as a negative electrode or a positive electrode in an electrochemical cell by using a suitable counter electrode. In another embodiment, the electrochemically active electrode material sorbed to the zeolite is aluminum or phosphorus, or an alloy or composition containing aluminum or phosphorus. In this case, the electrode material preferably consists of a halide, sulfide, selenide or oxide of aluminum or phosphorus. In addition, sulfur element or selenium element containing phosphorus in a small amount compared to sulfur element or selenium element as a negative element for stabilizing sulfur or selenium to lower the vapor pressure of sulfur or selenium is a sulfide of phosphorus. or is not considered a selenide and is not an electrochemically active electrode material for the electrodes of the electrochemical cells of the present invention. An electrode in which a transition element as an electrochemically active electrode material 7 is sorbed or adsorbed on zeolite, and halogen (oxide) ions are transferred from either the negative electrode or the electrolyte to the positive electrode during the filling process. In the case of electrodes used in such electrochemical cells, the electrodes may be activated by applying a voltage higher than the threshold voltage required to halogenate the reduction metal or compound of the transition metal.

The electrode can be activated in situ if the threshold voltage is lower than the electrolysis voltage that would decompose the electrolyte.
If the threshold voltage is higher than the breakdown voltage of the cell's electrolyte, the electrodes can be activated separately or together in a bath with a suitable separate electrolyte. This activated electrode is in the charging state of the battery, in the partially charged state,
Or it can be attached to a battery in a state when the battery is discharged. Of course, the electrode can be attached to the battery in the state of discharging the battery if the battery is a secondary battery. The zeolite constituting the molecular sieve carrier for holding the electrochemically active electrode material as active material in a trapped state may be a natural or synthetic zeolite, a physically and/or chemically modified modified zeolite. , or a zeolite-like substance.

The term ``zeolite'' refers to a group (Class 7) consisting of crystalline or amorphous natural or synthetic materials containing aluminum and silicon in approximately defined proportions, and their analogues such as sodalite. is Internat-10na1Uni0
n0fPureandApp1icdChemistry
y January 1975 document “Chemi-CalNOn
lenclature, andFOrmulationOn
OfCompOsitiOnsOfSynthetic
andNAtu-RalZeOlites. Zeolites contain water molecules in a sorbed state, which can usually be reversibly removed by heating and/or venting. In this specification, sorption is a general term for adsorption and absorption. In some cases, adsorption and absorption are used interchangeably. In the case of an electrochemical cell having an electrode in which the electrode material is sorbed to zeolite as a molecular sieve carrier, it usually does not operate efficiently even in the presence of a small proportion of water, and therefore, in this specification, the term zeolite as a molecular sieve carrier is used. Zeolite refers to completely dehydrated or partially dehydrated zeolite. Zeolites usually have a fairly ordered internal structure, a large internal surface area, and a large number of regularly arranged molecular cavities or pores. It is believed that in the dehydrated state, zeolites can be represented by the structural formula below. That is, where M is a cation of valence n, and X and Y are independent variables depending on the composition of the starting mixture and the method of formation.

According to the invention, the zeolite with pores such as molecular sieves is selected from the group of natural zeolites such as hawkiasite and erionite and the group of substances consisting of zeolite 3A, zeolite 4A, zeolite 5A and zeolite 13X, and is completely or Consists of partially dehydrated zeolite crystals.

Zeolite 4A has the following structural formula.

That is, however, the value of X may vary.

Zeolite 4A has pores with an inlet diameter or window diameter of about 4 angstroms and a volume of about 1000 (A) 3 . Zeolite 13X has the following structural formula. That is, with the proviso that X can vary over a wide range. Zeolite 13X has pores or molecular cavities with a pore diameter of about 13 angstroms. Regarding the zeolite crystal, it is preferable that the zeolite crystal has sufficient physical strength in order to be effectively used in the electrode, and furthermore, it is preferable that the zeolite crystal has sufficient physical strength to be used effectively in the electrode. It has been found that materials that are less susceptible to electrochemical damage during repeated use as carriers are preferred.

By the way, metal cations in zeolites, whether doped or not, can generally be replaced by other cations in an ion exchange process.

If such an ion-exchanged zeolite is used for the cathode of a battery, and the zeolite does not function merely as a carrier, the substituted cations become in fact the only major electrochemical reactant or active material of the cathode. , this positive electrode will physically and/or chemically disintegrate during use of the battery. This is because the ion-exchanged zeolite itself directly participates in the electrochemical reaction as a positive electrode. Such ion-exchanged zeolites should not be used as positive electrodes that directly participate in electrochemical reactions, since the collapse of the positive electrode leads to the failure of the battery. In fact, it is because of this cathode collapse that such batteries cannot be efficiently recharged and, in practice, cannot be used as secondary batteries. This point is in complete contrast to the present invention, in which the zeolite acts as an electrochemically inert support or frame, and does not play a significant role in the electrochemical reaction itself at the electrode. It constitutes a support or frame for the chemically active electrode material or active material.

That is, the structure is such that it does not disintegrate significantly due to electrochemical reactions during normal use and can maintain a stable state both physically and electrochemically. That is, when carrying out the present invention, when selecting a zeolite as a molecular sieve carrier for holding an electrochemically active electrode material, it is necessary to select one having the above-mentioned properties. When zeolites are doped with highly positive substances such as alkali metals or alkaline earth metals, the lattice of the zeolite changes substantially.

However, even with this lattice change, the zeolite functions as a molecular sieve carrier for alkali metals or alkaline earth metals and remains electrochemically sufficiently or relatively inert during battery use. I understood. If a zeolite doped with a specific electrochemically active electrode material and physically and/or chemically modified has certain zeolite-like properties as a carrier as described above, this zeolite can be used as an electrode material. It can be effectively used as a molecular sieve carrier. Additionally, in some electrochemical cells having certain zeolite-based electrodes, cation exchange may occur during use of the electrodes.

For example, lithium in the electrolyte may replace some sodium ions in the lattice of zeolite 3A. Such reactions are known and only change the opening and internal dimensions of the pores of the zeolite lattice. For example, if the sodium ions in zeolite 4A are replaced with potassium ions, the pore opening diameter changes from 4 angstroms to 3 angstroms, producing zeolite 3A. Also, in some cases, for example after being doped with lithium or after several charge-discharge cycles in a battery, the zeolite as the molecular sieve carrier of the electrode is no longer strictly in the form of the original zeolite. However, since these have appropriate zeolite properties, they can still be considered zeolites for the purposes of the present invention.
If the zeolite constituting the electrode support is in a modified zeolite form, this zeolite, even though physically or chemically modified, still accepts and entraps the electrochemically active electrode material. The pore size of the pores leading to the internal voids is less than about 70 to 100 angstroms, preferably less than about 30 to 50 angstroms.

When the zeolite constituting the electrode support is in the form of a zeolite-like material, the zeolite has cavities or pores for receiving and holding the electrochemically active electrode material in an entrapped state. The diameter of the pores leading to the voids is less than about 70 to 100 angstroms, preferably less than about 30 to 50 angstroms. In one preferred embodiment of the invention, the modified zeolites and zeolitic materials have pore sizes less than about 20 Angstroms. pore size, internal void size, uniformity of pore and internal void size, ability to sorb an electrochemically effective amount of electrochemically active electrode material, and said electrode material under the conditions of use. Taking into account factors such as the ability to hold zeolite in an entrapped state will provide rough guidance in selecting a zeolite for a particular application.

Still other factors that can help guide this include the electronic conductivity, porosity, density, availability, mechanical strength, and stability of the zeolite after doping with a given electrode material. When the zeolite constituting the support of the electrode sorbs an electrochemically active electrode material, it preferably contains the electrode material in a finely divided form, ie, preferably atoms, molecules, atomic groups, or diaphragms. By maintaining the electrode material in the form of a molecular group, it is configured to maximize the electrochemical activity of the electrode material during use. Further, desirably, the zeolite is such that it retains an effective amount of the electrochemically active electrode material in a state of entrapment for a sufficient period of time to enable the electrode to function effectively within the cell for a reasonable period of time.

When the electrode is a positive electrode, the zeolite that constitutes the support of the positive electrode is such that the electrochemically active positive electrode material is held in an entrapped state during use of the positive electrode over the normal operating temperature range of the cell. The battery may be one that does not run out much during a reasonable period of operation. The above requirements are generally met by most naturally available and synthetic zeolites.

Such special selection criteria are therefore important primarily in the case of modified zeolites and zeolitic materials. In order for an electrode with zeolite to sorb electrode material to work effectively, the electrode must be capable of allowing adequate ions to diffuse throughout the electrode during use in a battery. Therefore, the zeolite must be ionically conductive when doped with an electrochemically active electrode material. In addition, in this specification, "doped zeolite"
means a zeolite in which, according to the invention, an electrochemically active electrode material is sorbed into its pores. Generally, the greater the ionic conductivity of an electrode, the better the performance of a battery using such an electrode. On the other hand, as a matter of course, the electrode must be electronically conductive. By the way, natural and synthetic zeolites usually have poor electronic conductivity. Therefore, zeolites are selected that have good electronic conductivity when an effective amount of electrochemically active electrode material is sorbed into the pores. If not, a good electronically conductive material is included in the electrode. According to the invention, the zeolite-containing electrode may contain suitable electronically conductive materials, if necessary or desired. In this case, sufficient electronic conductivity is provided between individual crystals within the electrode, increasing the electronic conductivity of the electrode. In one embodiment of the invention, the electronically conductive material is a material having suitable electronic conductivity at the operating temperature of the battery, such as graphite or MOS2. If the electronically conductive material is graphite, this graphite may be in the form of a porous coating on the polycrystals of a molecular sieve carrier made of zeolite, or a powder mixed with the crystals. Here, the term "porous" coating means a coating that allows the electrolyte to freely enter and exit the pores of the zeolite and the voids or passages deep within the pores through the pores of the coating. The graphite coating layer must be porous, but the proportion of the graphite layer should be as small as possible if effective electronic conductivity is to be obtained during use, since the graphite layer may act as a barrier to the electrolyte. desirable. Therefore, in practice, the proportion of electronically conductive material to zeolite is selected to balance electrolyte accessibility and electronic conductivity during use in the battery.

Furthermore, it is preferred that the total mass of the electronically conductive material be as small as possible so that the energy-to-weight ratio is as high as possible. In a series of experiments, powdered graphite was mixed with undoped zeolite crystals in various proportions to produce pellets containing various proportions of graphite and zeolite. It has been found that adding about 5 to 16% graphite to the zeolite provides pellets with sufficient electronic conductivity for useful use. Furthermore, if you wish,
The proportion of powdered graphite may be considerably increased. The zeolite-containing electrode may contain 5 to 60% by weight of powdered graphite. If the electrode has a mixture of graphite powder and zeolite crystals and consists of a loosely compacted molded structure of said mixture, if the particle size of the graphite powder is too small, the electronic conductivity of the electrode will be large but during use. The movement of the electrolyte through the electrode will be poor, and vice versa if the graphite particle size is too large.

Therefore, it is preferable to strike an appropriate balance in this regard in practice. A series of experiments were carried out using graphite in the form of a colloidal suspension instead of graphite in powder form.

In this experiment, a relatively low concentration of graphite colloid suspension was used to treat the zeolite sample. After drying, the treated zeolite was found to be electronically conductive. Therefore, it is considered that a graphite coating was formed on the zeolite crystal. Zeolite crystals can also be coated with graphite by other techniques, such as vapor phase coating.

In other words, in order to impart electronic conductivity to the zeolite crystal,
Organic component vapors may be decomposed on the crystal surface, resins or pitches mixed with zeolite crystals may be decomposed, and metal carbonyl vapors such as tungsten hexacarbonyl may be decomposed. Note that decomposition of tetrafuran may also be used. If the support made of zeolite has poor electronic conductivity and the electrochemically active electrode material sorbed onto the zeolite has poor electronic conductivity, the sorbed active material or electrode material will have low utilization. In addition, the internal resistance of the battery increases.

This problem can be solved by impregnating the zeolite support with an electrochemically inert current collector (which does not participate in the electrochemical reactions of the cell). This impregnation step can be carried out before the electrochemically active electrode material is sorbed onto the zeolite. This current collector is made of, for example, silver, aluminum, or carbon. Said measures are also taken when the zeolite-containing electrode constitutes the negative electrode in electrochemical cells in which during discharge a migration of cations from the negative electrode to the positive electrode occurs.

The inert current collector that remains within the electrode tends to prevent the negative electrode from becoming non-conductive until the end of the discharge cycle. This is particularly important in the case of batteries whose capacity is defined by the negative electrode. Electrodes with a support made of zeolite can be suitably compacted, suitably compacted with a binder, supported with a binder, held in another support structure or matrix, or housed in a porous electrode holder. It may be in the form of a structure or matrix that is self-supporting, ie, able to maintain its shape without further support by additional supports. For example, an electrode with a zeolite support may be housed in a suitable porous, corrosion-resistant electrode holder. In this case, the holder consists, for example, of a porous graphite cup. If the electrode is a compacted type electrode, compaction of the zeolite support may be performed before or after the electrode material is sorbed therein, but it is preferable that the zeolite support be compacted after the electrode material is sorbed therein. After that, compaction is performed.

Zeolites can be compacted, for example, by compression operations, hot compression operations, sintering operations, sintering operations with compression, and the like.
The reason for performing this compaction operation is to optimize volume, increase electronic conductivity, and mold into the desired shape. The compaction method used depends on (a) the properties of the zeolite and dopant with respect to fracture temperature and mechanical properties;
(b) Target physical shape/dimensions (c) Target electrochemical properties may be selected depending on the target.

Compaction of the electrodes improves contact between particles and increases electronic conductivity.

However, compaction of the electrode can reduce porosity and adversely affect the diffusion of electrolyte into the electrode during use of the electrode. Compaction of the electrode can form an electrode disk or pellet that is virtually self-supporting, ie, mechanically rigid enough to maintain its shape and not collapse. If the disk or beret has a mechanical strength so great that it does not lose its shape even without the use of a separate support,
They can be used in batteries without a holder or support. However, it is still preferable to use it while being housed in a porous cup-like or bag-like holder. This is because, even if the disk or pellet should break during use, or the cup or bag should break, the electrode can still remain in almost its original state. As mentioned above, the compaction of an electrode having a support made of zeolite requires that the electrolyte sufficiently approach or access the electrochemically active electrode material of the electrode and that a large current density can be obtained; This is done as desired in order to satisfy both the requirements of having high mechanical strength and high electronic conductivity.

If the electrode with a support made of zeolite is suitably compacted, the volume-to-mass ratio of the electrode is improved.

This compaction improves the electronic conductivity, so that the relative mass of the electronically conductive coating material is also small, allowing the overall mass of the electrode to be relatively small. Furthermore, handling becomes easier in the case of a self-supporting electrode that maintains its shape without the use of a separate support. Using suitable compression techniques, zeolites can be formed into very thin plates (for example 0.111 m thick plates). This plate is particularly suitable for use with organic and solid electrolytes, which by their nature have a lower ionic conductivity than molten electrolytes of ionic salts. Additionally, the electrode may have an electrochemically active collector portion connected electronically, i.e., in an electron conductive manner, to the electrode body to collect free electrochemical reaction products during use in a battery. . Here, the electrode body refers to (an aggregate of) zeolite on which the electrode material is adsorbed. The collector section is made of dehydrated zeolite crystals treated with an electron conductive material to impart electron conductivity to the collector section. This electrochemically active impregnated zeolite participates in the reactions throughout the cell. The electronically conductive material and the treatment of the zeolite crystals therewith have been previously described in this specification. The electrode or electrode body is preferably in physical contact with the active 111 collector and, if necessary, the electrode or electrode body is surrounded by or contained within an active collector. It's good to be able to do it.

In addition, a layer of dehydrated electron-conductive zeolite particles is solidified on the electrode or electrode body formed in advance, or a part of the support made of zeolite is sorbed with an electrochemically active electrode material. A composite electrode can be formed from the electrode (main body) and the collector portion by using the collector having the ability to adsorb the remainder of the Φzeolite. The collector part has electron conductivity and is electronically (electronically conductively) connected to the electrode (main body), so this collector part constitutes a part of the electrode and therefore affects the capacity of the battery. can contribute. In this case, the free electrochemical reaction products are collected in the collector section during use of the cell and do not remain near the electrodes and current collector. The battery electrodes further include a conventional type of electrochemically active electrode (body) and an electronic (body) electrode (body) to collect the free electrochemical reaction products produced during operation of the battery. an anhydrous or dehydrated zeolite crystal body having pores of less than 100 angstroms, and an electron conductive material that imparts electron conductivity to the collector; A composite electrode consisting of

For example, the electrode may consist of iron sulfide or iron disulfide, or iron sulfide or iron disulfide sorbed onto anhydrous zeolite coated with graphite, and the active collector portion physically attaches to the carbon layer surrounding the electrode. It consists of anhydrous to dehydrated zeolites that are physically and electronically (electronically conductively) in contact. In this case, for example, a negative expression consisting of Ll and At and, for example, KCL and LlCf! ．． During use as a battery positive electrode with a molten electrolyte consisting of ionic salts such as LlI and KI, liberated products such as iron chloride, sulfur, and alkali polysulfides are collected by the collector section. Removal of such products not only reduces contamination within the battery, but also allows the formation of complex phases such as the well-known "J" phase in secondary reactions to collect or remove the primary chemical reaction products necessary for their formation. Therefore, it can be suppressed. Additionally, it is believed that the presence of this collector portion electronically connected to the positive electrode may improve the battery's ability to tolerate overcharging and overdischarging. As described above, according to the present invention, there is provided a chemical battery comprising a positive electrode, a negative electrode, and an electrolyte, in which at least one of the positive electrode and the negative electrode is made of an electrochemically active electrode material and an electronically conductive and ionically conductive electrochemically inert support comprising a zeolite having a large number of pores small enough to trap and hold the electrode material therein during discharge operation; Substantially all of the active electrode material is sorbed within the pores such that the exchangeable cations of the zeolite do not substantially participate in cell reactions and are removed from the cell. such that substantially all of the energy extracted is given to the electrode material retained within the pores, and the electrode material further comprises: (a) a halogen, an alkali metal, an alkaline earth metal; , first and second series transition elements, lead, phosphorus, arsenic, antimony, bismuth, and aluminum, or (b) oxygen, sulfur, Alternatively, there is provided a chemical battery comprising a composition containing selenium, but excluding elemental sulfur and elemental selenium.

It should be noted that the fact that substantially all of the energy extracted from the battery is given to the electrode material held within the pores means that the zeolite does not substantially participate in the electrochemical reactions that determine the battery's capacity (energy). refers to something.

When only one of the electrodes has the above electrode configuration,
The remaining electrodes take the form of regular electrodes.

That is, for example, the remaining electrodes may be an alkali metal, a combination of alkali metals, an alkaline earth metal, a combination of alkaline earth metals, a combination of alkali metals and alkaline earth metals, or an alkali metal and/or alkaline earth metal. It takes the form of a negative electrode made of an alloy or composition containing metal. It may also be a positive electrode consisting of a negative material held in entrapment in the form of a suitable alloy, compound or element so that the remaining electrode can move effectively within the cell. Furthermore, the remaining electrode may be a positive electrode or a negative electrode made of a reduced metal or a compound, alloy, or composition of reduced metal. Both cells according to the invention preferably have electrodes of the type described above, ie electrodes in which the electrode material is sorbed onto a zeolite support.

The battery further includes a pair of electrodes and an electrolyte, and further includes an electronically conductive active collector as described above comprising a zeolite having a pore size of less than 100 angstroms and electronically connected to one of the electrodes. It's okay to be hot.

The electrolyte of the battery may be a solid electrolyte, an electrolyte in a liquid state at the operating temperature of the battery, or an electrolyte sorbed or impregnated in a suitable zeolite.

If the electrolyte is to be sorbed or impregnated into a zeolite, the zeolite is preferably as described above;
Preferably, the zeolite consists essentially entirely or partially of dehydrated zeolite crystals. The electrolyte provides a source of dissociated metal and halogen ions.

In this case, for example, the electrolyte can be a salt consisting of an alkali metal or alkaline earth metal halide, such as sodium chloride, calcium chloride, calcium fluoride, magnesium chloride, lithium bromide, and the like. The electrolyte may be a mixture containing two, three, etc. halide salts of alkali metals and/or alkaline earth metals. In this case, the electrolytes are, for example, lithium iodide and potassium iodide, lithium chloride and potassium chloride,
It consists of lithium chloride and magnesium chloride, lithium bromide and potassium bromide, lithium fluoride and rubidium fluoride, linium chloride and lithium fluoride, or calcium chloride and lithium chloride. Furthermore, the electrolyte consists of an alkali metal or alkaline earth metal halide electrolyte dispersed in an aprotic solvent.

The aprotic solvent may be any suitable solvent, such as propylene carbonate. For example, a molten electrolyte consisting of alkali metal halide salts may contain an aluminum halide (eg, Atct,) or other suitable additives to lower its melting point.

In this case, the electrolyte is, for example, a mixture or double salt of an alkali metal halide and an aluminum halide, or a mixture of an alkaline earth metal halide and an aluminum halide, or a double salt thereof, or These mixtures form a rut.

The electrolyte is, for example, NaAtct4, LiAtCt4, K
AtCt4, NaAtBr4, LlAtBr4, KAt
Br4, NaAtI4, LiAtI4, KAtl4, M
r(AtCt4)2, Ca(nωT4),, Mr(At
Br4), Ca(AD3r4)2, Mr(AtI, ),
, Ca(AtI,), etc. may be used. Electrolyte mixture:
or in the case of a melt, it is desirable to φ with a eutectic mixture or a melt. In batteries, the negative electrode may be made of porous lithium or sodium, or lithium or sodium sorbed on zeolite crystals, or lithium.
Made of aluminum alloy or lithium-silicon alloy.
In this case, the positive electrode is formed by adsorbing a halide of a transition element as a positive electrode material onto zeolite. Here, the transition element halide is, for example, cobalt chloride, iron chloride, chromium chloride, titanium chloride, or manganese chloride. In making this cathode, the zeolite crystals are substantially completely or at least partially dehydrated and the zeolite pores are doped with a material that forms an electrochemically active cathode material using well-known techniques. do. For example, FeC4 can be impregnated directly into the zeolite crystals from the liquid or gas phase. If the electrochemically active cathode material is chromium chloride, the chromium can be sorbed onto zeolite crystals in the form of low melting chromium oxide and then reduced to metallic chromium using hydrogen. The chromium can then be chlorinated prior to use or, if the electrolyte is suitable, chlorinated to activate the positive electrode during charging. In this case, the positive electrode is a three-dimensional positive electrode formed by sorbing the transition elements that make up the positive electrode material onto zeolite, and the positive electrode material remains in a well-dispersed and electrochemically reactive state for the normal operating period of the cell. is held in an entrapped state in the zeolite. Therefore, in some cases,
It is also possible for each transition element ion to take a strong oxidation state, thereby making it possible to fully utilize the electrochemical potential of the transition element. When selecting an electrochemically active cathode material or cathode active material as the cathode material, it can be sorbed onto the zeolite in a well-dispersed state and remains in the zeolite during normal operation of the battery at the designed operating temperature of the battery. It is preferable to choose a material that is as light as possible, which can be held in a trapped state, and yet has as large a negative oxidation potential as possible, so that the cell can operate effectively for a sufficient period of time.

The electrolyte phase may be any electrochemically compatible electrolyte phase, but when selecting an electrolyte, the following are preferred:

That is, it has a low melting point, is non-corrosive and non-toxic, has compatibility with negative electrodes and positive electrodes, has low density, high electrical conductivity, has as large a decomposition voltage as possible, and under the conditions of use. Chemically and thermally stable electrolytes are preferred. The electrolyte preferably consists of, for example, a eutectic chloride of lithium and aluminum having a melting point of about 100°C. still,
This lithium-aluminum chloride melt may be doped with various alkali metal halides or alkaline earth special metal halides to lower the melting point below 100°C. When the cathode material is FeCl3, LiFeCI4 is formed on the charged cathode, which is considered insoluble in the LiAlCl4 electrolyte.

If so, the movement of Fe ions is suppressed. When Fe ions are trapped in sorbed zeolite crystals, they are more difficult to migrate. The same would apply when other transition elements are used as the positive electrode material instead of iron. A disadvantage found in experimental cells is that when the cell is charged and the Fe content of the cathode is converted to FeCl, the electronic conductivity of the cathode can sometimes decrease.

It is therefore preferable to add a small amount of a suitable inert current collector, such as a noble metal or graphite, to the positive electrode to increase its inherent conductivity. This further increases the depth of charging. Electrolytes made of chlorides of lithium and aluminum are preferred because they have a low melting point, are compatible with positive electrodes containing transition metal chlorides, are compatible with suitable negative electrodes, are compatible with zeolites, and are inexpensive. .

When the electrolyte has a relatively low melting point, inexpensive, lightweight battery casings and relatively simple heating equipment can be used that are not readily available for high melting point electrolytes.

This may improve cost and power-to-weight ratio.
As a result of experimental experiments, we found that when an appropriate alkali metal or alkali metal alloy is selected as the negative electrode and an appropriate electrolyte is selected, the electronegativity of the positive electrode with respect to the negative electrode is completely different from that of the positive electrode in some cases. Preferably, the selection is based on other factors. This means, for example,
This is illustrated by comparing a negative element such as sulfur to a negative element such as iron in the case where the negative electrode is lithium and the negative element is sorbed into the crystals of dehydrated zeolite.

In the case of sulfur batteries, sulfur has a maximum state of S-2.

When considering the mass of only electrochemically active elements, the capacity is 1.67 Ahr/y. Sulfur is cheap, but
Because of the electrolytes that are commonly used, the required cell operating temperatures are typically higher than at least about 250°C, which requires sophisticated heating equipment and stainless steel housings. +On the other hand, in the case of iron cells, iron has a maximum oxidation state of Fe3.

When considering the mass of iron only, the capacity of the electrode is 1.44Ah
It is r/7. Fe and FeCl3 are cheaper than sulfur. If at least alkali metal halides and alkali metal and aluminum halides are used as the electrolyte, the operating temperature of the battery will be approximately 100° C. or less, so that a relatively simple heating device and a housing made of synthetic resin material, for example, are required. It becomes possible to use an inexpensive and lightweight housing. As mentioned above, even if the electronegativity of iron is small compared to sulfur, this can be compensated for if the oxidation potential of iron can be fully utilized, and even if cost etc. is an issue, iron It is believed that problems due to the large mass of iron compared to sulfur can be compensated for because relatively inexpensive battery housings and heating devices are used in this case.

In addition, when an electrochemically active electrode material is sorbed into zeolite crystals, it is necessary to take into account the sorption rate to zeolite and the mass of zeolite in the comparison.

For example, it can be seen from the table below that negative elements such as vanadium, chromium, and manganese sorbed in zeolite crystals are more desirable than iron because they are lighter than iron and have a higher maximum oxidation state.

That is, the battery according to the present invention can be used as a primary battery or a secondary battery, that is, a rechargeable battery. However, some batteries according to the invention are generally useful only as primary batteries. For example, if the electrode is made of zeolite sorbed with sodium, during battery charging the sodium will not enter the zeolite lattice, but will be selectively plated onto the outer surface of the electrode.

Therefore, such a battery would effectively only operate as a primary battery. The same applies to lithium. Furthermore, a battery in which the positive electrode has halogen adsorbed on zeolite actually operates only as a primary battery. The battery according to the invention can be easily assembled into a storage battery. Next, specific examples of the present invention will be described below by way of example based on the accompanying drawings and certain experiments and preliminary experiments.

In FIG. 1, reference numeral 10 designates an electrochemical cell according to the invention.

This battery 10 includes a negative electrode 12, a positive electrode 14, and a casing 1.
8 and an electrolyte 16 housed within the cell. The negative electrode 12 is
It consists of a positive material consisting of an alloy of lithium and aluminum.

The electrolyte 16 includes KCl and LiCl (the operating temperature is approximately 40°C).
0° C.) or a molten electrolyte consisting of salts such as LiI and K (working temperature approximately 300° C.). The positive electrode 14 is in the form of a composite positive electrode according to the present invention.

This positive electrode 14 consists of a porous positive electrode compact (hereinafter referred to as a compact) 22 consisting of a dehydrated zeolite crystal compact in which iron sulfide or iron disulfide is adsorbed and coated with graphite, and a lower end inside the compact 22. The current collector 20 is made of steel or iron and has a part buried therein. This positive electrode 14 further includes:
An electronically conductive trap 24 that is electronically (electronically conductively) connected to the compact 22 that is the main body of the positive electrode 14
has. This collector 24 consists of a layer of dehydrated or anhydrous zeolite particles compacted on the positive electrode compact 22.
The zeolite particles of the collector 24 are treated with graphite as described above so as to impart electronic conductivity to the zeolite particles. This treatment with graphite facilitates fixation of the collector layer 24 to the positive electrode compact 22. The positive electrode compact 22 is completely surrounded by a collector 24 , which surrounds a portion of the current collector 20 located within the casing 18 . In this case, the battery 10 is in use. Undesirable electrochemical reaction products such as iron chloride, sulfur and iron are collected in collector 24.

Therefore, not only can such products be substantially removed and contamination of the battery can be suppressed, but also the formation of a complex phase such as the well-known "J" phase in the secondary reaction can be used to collect the primary reaction products. It can be suppressed by removal. After charging and discharging the battery 10 several times, the electronically conductive collector 24, which is electronically connected to the positive electrode compact 22 and the current collector 20, has collected electrochemically active substances. This collector 24 actually constitutes one electrode of the battery 10.

That is, the collector 24 constitutes an electrode made by adsorbing an electrochemically active electrode material onto a support made of zeolite. In this manner, since the collector 24 constitutes another electrode, it is believed that the collector 24 may contribute to the capacity of the battery 10 and may improve the ability of the battery 10 to tolerate overcharging and overdischarging. In preliminary experiments carried out on such cells, this voltage was found to be 1.6 V per square meter.
Open circuit voltage of about 1A, short circuit current of about 150mAh
It had a capacity of r/f.

In FIG. 2, a reference numeral 30, a negative electrode 32, a positive electrode 34,
f) An electrochemical cell consisting of an electrolyte 36 housed within a casing 3.

The negative terminal 32 has a current collector 40 and the positive terminal 34 has a current collector 42. Using the TJO battery 30 as described above, many experiments and preliminary experiments were conducted on various modified electrochemical cells. Experiments were conducted on seven types of electrochemical cells.

The details of these seven types of batteries and the average results of each experiment are shown in Tables 1 and 1. In order to impart this, an electronically conductive material such as graphite was included in the zeolite.

Although there are cases where doped zeolite crystals have sufficiently good electronic conductivity (e.g. zeolite 4A/silver electrodes), the electronic conductivity of the electrode is usually improved by including an electronically conductive material. It is desirable to increase it. In the experiments summarized in the tables above, only zeolites 4A and 13X were used as zeolite supports;
Separate experiments have shown that if the pores and cavities deep within the zeolite lattice are capable of holding the electrochemically active electrode material in a dispersed state within the pores or cavities of the zeolite lattice, other zeolites may be used. It has been found that supports can also be used.

In addition to the experiments summarized in the preceding tables, certain preliminary experiments were conducted using alkaline earth metals instead of alkali metals as the electrochemically active electrode materials.

In preliminary experiments, for example, Ze-4A/S was used as the negative electrode (graphite) and Ze-4A/S (black spade was used as the positive electrode).
The experiment was carried out using Li.K as an electrolyte. This cell had an open circuit voltage of about 1.6 volts, a short circuit current of about 800 mA, and a capacity of about 100 mAh/f. It has been more difficult to impregnate zeolites with alkaline earth metals than with alkali metals. In addition to the experiments described above, further preliminary experiments were conducted using iron sulfide as the electrochemically active electrode material. Zeolite 13X, which has been treated with graphite to increase its electronic conductivity, was impregnated with iron sulfide.

This impregnation procedure was carried out, for example, by impregnating the zeolite 13X with FeCl or FeCl3. after that,
For example, FeS was impregnated into the pores or cavities of the zeolite by introducing sulfide ions from a Na2S solution or H2S gas. In the preliminary experiment conducted,
The negative electrode was Ll-At and the electrolyte was LlI-K.
This battery has an open circuit voltage of approximately 1.4 volts and a
A short circuit current of approximately 120. It had a capacity of mAhr/V. In the fourth column of experiments shown in Table 1 above, FeCl3 sorbed on the zeolite is reduced to elemental iron when the cell is fully discharged.

The electrochemically active electrode material therefore consists of the element iron sorbed onto the zeolite δ in the discharge state of the positive electrode. This is also true for other transition elements. In further preliminary experiments with transition elements, both silver and copper were sorbed onto zeolite 4A to form negative electrodes for electrochemical cells. It turns out that it can be done.

When using this negative electrode, the battery is, for example, Ze-5A/2
positive electrode in the form of , and LiCl in carbonate of propylene
It consists of an electrolyte like a solution. Using silver as the active negative electrode material, preliminary experiments indicate that the cell has an open circuit voltage of about 0.5 volts, a short circuit current of about 20 mA, and a capacity of about 30 mAh/Ft. Ta. In yet another experiment conducted, Li-Al was used as the negative electrode, LiAlCl4 was used as the electrolyte, and Z was used as the positive electrode.
e-4A/1SJa2SX was used.

This battery has an open circuit voltage of 1.86 volts and an 800 mA
short circuit current, 150mAhr/r capacity, 74% Coulombic efficiency, 200℃ operating temperature, 4 charging/discharging times.
It had a battery life of two or more times. Regarding Table 1 and the seven series of experiments described in the table above, the following conclusions were obtained. Experiment 1 This cell had the best discharge characteristics in the first operating cycle, which is considered preferable as a primary cell than as a secondary cell.

The low Coulombic efficiency may be due to an internal short circuit caused by lithium particles between the negative and positive electrodes. The electron conductivity was very low and the initial discharge was good. This also limited short-circuit current. The reason why the life was relatively short is considered to be that CrO3 was lost from the crystal structure of the zeolite because the impregnation was carried out at 250°C. Capture or pinning of electrochemically active electrode materials (P
Inning is believed to be much more effective with electrolytes used at relatively low temperatures, such as LiAlCl4, and pinning is believed to occur effectively with zeolites during use. Experiment 2 Red phosphorus was impregnated into zeolite 13X at 265°C for 6 days.

This zeolite was selected because its pore diameter, which connects to deep grooves and cavities, is 8 to 9 angstroms. In this case, P4 molecules can easily diffuse into the zeolite lattice. The lifespan of this battery is Zeolite 5
It is thought that this can be improved by using A. This zeolite 5A has pores with a pore diameter of 4 to 5 angstroms. The tetrahedral P4 molecule has a diameter of approximately 7 angstroms. Therefore, for impregnation, P4 molecules must dissociate into P2 molecules that can be sorbed into the zeolite. Within the deep cavities of the zeolite pores, P4 molecules can be re-formed from the P molecules, and these molecules are tightly pinned within the zeolite support for effective use in the battery. This cell may also have a longer useful life at lower operating temperatures by using another low melting point electrolyte. Experiment 3 A large short circuit current was obtained due to the sorption of a significant amount of AlCl3 onto zeolite 4A.

The Coulombic efficiency was low due to the formation of dendrites. Initial charging took a long time because it was necessary to charge the negative electrode after activating it. It is believed that by using a better separator than the ceramic separator used (which gave rise to dendrite formation), the life of this cell could be significantly improved. After the 44th charge/discharge cycle of the experiment, the discharge capacity of this battery steadily decreased.

After 22 charges and discharges (14 days), this discharge capacity is approximately 45
It decreased to n1Ahr/r.

This decrease in battery capacity is believed to be due to the loss of FeCl3 in the zeolite due to dissolution of FeClst)S from the zeolite into the electrolyte due to the high operating temperature. If the battery is made to operate at relatively low operating temperatures by using different electrolytes, FeCl
It is considered that No. 3 is sufficiently pinned by zeolite and can be effectively used as a secondary battery. Experiment 5 This battery is promising as a primary battery due to good results in the first discharge cycle (capacity = 400 mAh/t).

The capacity of this battery is 100% in the second discharge cycle.
It slowed down to mAhr/V, and then it practically stopped working. Implementation 6 The reason why the short circuit current is small is mainly due to the difficulty in dissolving lithium bromide in the organic solvent, the problem of drying the organic solvent, and the difficulty in keeping the negative electrode surface clean. It is thought that

It is believed that with appropriate measures these problems can be overcome and the short circuit current can be increased. Experiment 7 This type of battery is thought to be primarily used as a primary battery because lithium is selectively plated on the outer surface of the negative electrode during charging and does not return to the cavity deep within the zeolite pores. .

Furthermore, the experiments conducted showed that lithium chemically modifies the zeolite structure during sorption. Nevertheless, the modified zeolite structure appears to retain sufficient zeolite-like properties to provide the negative electrode in this experiment with negative electrode activity. However, the capacity of this battery is relatively small. From Table 1 and the experimental results shown in the table,
It can be seen that the operating temperature of the battery was too high in most experiments. This is due to the electrolyte used. The degree to which the electrochemically active electrode material is retained (immobilized) within the zeolite depends on the type of zeolite, the type of electrochemically active electrode material, and the operating temperature. The operating temperature may be increased to a more practical degree, e.g. from about 250°C to about 1
When lowered to below 00°C, the electrochemically active electrode material can be held tightly by the zeolite in order to be effectively used in the cell. Furthermore, if the size of the zeolite's pores and the cavities deep within the pores match the electrochemically active electrode material, the electrochemically active electrode material will be reliably retained within the zeolite and used effectively. be done. Furthermore, the electrochemically active electrode material is composed of finely dispersed atoms, molecules, and atomic groups that, when sorbed within the zeolite, can be freely accessed and produce effective electrochemical activity. It is retained in the zeolite in the form of clusters.

Therefore, electrochemically active substances contained in microporous materials such as physical sponges, spongy metals, activated carbons, felts, etc., can be mixed with zeolites to the extent of dispersion or immobilization or pinning of the active material. This is considered to be significantly inferior to electrochemically active electrode materials sorbed to . Furthermore, the pinning properties of the zeolite required in a given electrode will vary depending on whether the electrode is positive or negative, and whether the electrochemical activity of the cell involves movement of active ions relative to the negative electrode. Regarding other methods of pinning active materials, such as by using electrochemically active electrode materials in the form of compounds or alloys, these methods reduce the electrochemical activity of the active materials and reduce the cell voltage and Reduces energy density. In contrast, the pinning of electrochemically active electrode materials with zeolites does not reduce the electrochemical activity of the electrode materials, increases the availability of the electrode materials or active materials, and increases the reactivity. have an effect. A support made of zeolite has the following advantage: the smaller the pore size of its lattice, the more difficult it is for the sorbed substances to be desorbed.

This therefore has the potential to enable use at relatively high operating temperatures. In some cases, the zeolite support can physically prevent chemicals that are too large from entering the pores or cavities. In this case, the active material pinned in the deep cavities of the pores of the zeolite support can be protected from reactions that can be detrimental to the battery. As described above, in the chemical battery of the present invention,
At least one electrode of the positive electrode and negative electrode of the battery,
an electronically and ionically conductive electrochemically active zeolite containing a large number of pores small enough to hold the electrochemically active electrode material therein in an entrapped state during the discharging operation of the battery; substantially all of the active electrode material is sorbed within the pores, so that the electrochemically active electrode material, i.e., the electrode active material, is reactive. It is held in a support made of zeolite in a highly fine state and three-dimensionally dispersed within the many pores of the zeolite.

Moreover, since this support is ionically conductive and electronically conductive, the electrode active material sorbed into the pores of the electrode can effectively directly participate in the electrode reaction. Therefore, in the chemical battery of the present invention, the energy of the battery can be extracted effectively and with a relatively large current.

Furthermore, in the chemical cell of the present invention, substantially all of the electrode active material is sorbed within the pores of the zeolite constituting the electrochemically inert support and remains trapped during the discharging operation of the cell. A variety of batteries using each of the various electrode active materials can be configured as a rechargeable secondary battery at a suitable temperature to be retained and thereby immobilized during the discharge operation of the battery.

[Brief explanation of drawings]

FIG. 1 is an illustration of an electrochemical cell according to a preferred embodiment of the present invention, and FIG. 2 is an illustration of another embodiment of an electrochemical cell according to the present invention used for the conducted experiments. 10,30... Electrochemical electricity? 1! ．． 12,32
゜゜゜゛゜゜Negative &. 14, 34... Positive Ll6
, 36... Electrolyte, 18, 38... Casing, 20, 40, 42... Current collector, 22... Positive electrode compact, 24...・・・
Collector.

Claims (1)

[Scope of Claims] 1. A chemical battery comprising a positive electrode, a negative electrode, and an electrolyte, wherein at least one of the positive electrode and the negative electrode comprises an electrochemically active electrode material and an electronically conductive and ionically conductive electrochemically inert support comprising a zeolite having a large number of pores small enough to hold the electrode material therein in an entrapped state;
Substantially all of the active electrode material is sorbed within the pores such that the exchangeable cations of the zeolite do not substantially participate in cell reactions and are removed from the cell. such that substantially all of the energy extracted is given to the electrode material retained within the pores, and the electrode material further comprises: (a) a halogen, an alkali metal, an alkaline earth metal; , first and second series transition elements, lead, phosphorus, arsenic, antimony, bismuth, and aluminum, or (b) oxygen, sulfur, or a chemical battery consisting of a composition containing selenium, but excluding elemental sulfur and elemental selenium. 2. The battery according to claim 1, wherein the composition a or b contains carbon, boron, silicon, or nitrogen. 3 The electrode material is lithium, sodium, potassium,
Claim 1 consisting of a positive substance selected from a substance group consisting of magnesium and calcium, or a composition or alloy containing at least one substance from this substance group.
The battery according to item 1 or 2. 4. The battery according to claim 1 or 2, wherein the electrode material comprises a halide, sulfide, selenide or oxide of a first series transition element. 5. The battery according to claim 4, wherein the transition element is chromium, iron, or manganese. 6. Claim 1, wherein the electrode material comprises aluminum halide sulfide, selenide, or oxide.
The battery according to item 1 or 2. 7. The battery according to any one of claims 1 to 6, wherein the zeolite comprises natural or synthetic dehydrated zeolite crystals. 8 Zeolite crystals include hojasite, erionite,
The battery according to claim 7, which is selected from the group consisting of zeolite 3A, zeolite 4A, zeolite 5A, and zeolite 13X. 9. The battery according to any one of claims 1 to 8, wherein the support contains graphite so that the at least one electrode has sufficient electron conductivity. 10. The battery of claim 9, wherein the graphite is in the form of a powder mixed with zeolite powder. 11. Claims 1 to 10, wherein the support has an electrochemically inert and electronically conductive current collector impregnated into at least a portion of the pores.
The battery described in any of the paragraphs. 12. A battery according to any one of claims 1 to 11, wherein the electrolyte is a liquid at the operating temperature of the battery. 13. The battery according to claim 12, wherein the electrolyte comprises a mixture of a plurality of alkali metal and/or alkaline earth metal halide salts. 14. The battery according to any one of claims 1 to 12, wherein the electrolyte comprises a mixture of an alkali metal halide and an aluminum halide.