JP5892434B2 - Secondary battery - Google Patents

Description

The present invention relates to a new secondary battery and an electrolytic solution for a secondary battery that are inexpensive and lead to energy saving and CO ₂ reduction.

  Secondary batteries are used in various electronic devices such as portable devices, notebook computers, and portable devices. In particular, a lithium ion secondary battery has a high energy density and a high voltage, and there is no phenomenon (so-called memory effect) in which the battery capacity gradually decreases when the battery is charged before it is completely discharged during charging and discharging. Therefore, it is widely used as a power source for electronic devices.

Currently, as a measure to prevent global warming, efforts are being made to reduce CO ₂ emissions on a global scale. Under such circumstances, there is an urgent need to develop and popularize next-generation clean energy vehicles such as plug-in hybrid vehicles and electric vehicles that are low in oil dependence and can contribute to CO ₂ reduction. Lithium ion secondary batteries are also expected as the driving force for these next-generation clean energy vehicles.

  Specifically, the lithium ion secondary battery includes a positive electrode, a negative electrode, a separator, and a nonaqueous electrolytic solution (see Patent Document 1). The positive electrode is configured by providing a current collector such as an aluminum foil with a mixture layer containing a positive electrode active material, a binder and a conductive agent. The negative electrode is formed on a current collector such as a copper foil. A mixture layer containing a substance, a binder, and a conductive agent is provided. Among these, the positive electrode active material is a lithium transition metal composite oxide such as lithium cobaltate or lithium nickelate, and the negative electrode active material is graphite or various alloy materials. However, such a lithium secondary battery has a drawback that a special and expensive lithium transition metal composite oxide is used as a positive electrode active material.

  On the other hand, molten salt batteries such as zebra batteries have been proposed as secondary batteries other than lithium secondary batteries. In the zebra battery, the positive electrode is nickel Ni, the negative electrode is molten sodium Na, the electrolyte is sodium aluminum chloride (melting point: about 160 ° C.), and the operating temperature is 250 ° C. However, such a molten salt battery does not operate at room temperature and is insufficient as an energy-saving secondary battery.

  Note that Patent Documents 2 to 4 disclose secondary batteries, respectively.

JP 2006-310010 A International Publication No. 2013/108309 International Publication No. 2010/073978 JP 2007-200966 A

An object of the present invention is to provide a new secondary battery and an electrolytic solution for a secondary battery that are inexpensive and lead to energy saving and CO ₂ reduction.

A secondary battery according to the present invention for solving the above problems includes a positive electrode containing a metal as a positive electrode active material, a negative electrode, and an electrolyte solution.
The electrolyte includes an electrolyte and a solvent;
The electrolyte includes an ionic compound that ionizes into a metal ion material and an anion material .

In the secondary battery according to the present invention, a metal salt compound that is ionized into a metal ion substance and an anion substance is provided in a solid state on the negative electrode ,
(A) During charging,
As the anion substance in the electrolyte and the metal ion substance ionized from the positive electrode active material are combined at the positive electrode, a compound precipitate is generated,
A metal ion substance ionized from the metal salt compound provided in a solid state on the negative electrode is reduced in the negative electrode, whereby a metal precipitate is generated in a solid state on the negative electrode,
(B) During discharge,
The anion substance is ionized from the compound precipitate and returned to the electrolyte solution, and the metal ion substance is ionized from the compound precipitate, and the ionized metal ion substance is reduced to the metal by the positive electrode. As we return,
The metal ion substance ionized from the metal deposit may return to the metal salt compound in a solid state on the negative electrode .

In the secondary battery according to the present invention, the negative electrode contains a conductor, and the standard electrode potential of the metal of the positive electrode active material and the standard electrode potential of the negative electrode conductor constitute the ionic compound . It can be configured to be larger than the standard electrode potential of the ionic substance . At this time, the standard electrode potential is preferably −0.257 V or more.

In the secondary battery according to the present invention, the metal ion substance constituting the ionic compound can be any one selected from lithium, sodium, potassium, magnesium, calcium and aluminum, and the electrolyte solution is non-ionic. It can be configured to be a water electrolyte.

According to the present invention, it is possible to provide a new secondary battery and an electrolyte for a secondary battery that are low in cost and lead to energy saving and CO ₂ reduction. In particular, it can be operated at room temperature without using an expensive active material.

It is explanatory drawing of the principle of the secondary battery which concerns on this invention. It is explanatory drawing which shows an example of the secondary battery which concerns on this invention. It is explanatory drawing which shows another example of the secondary battery which concerns on this invention. It is explanatory drawing which shows another example of the secondary battery which concerns on this invention.

  Hereinafter, a secondary battery and an electrolyte for a secondary battery according to the present invention will be described with reference to the drawings. In addition, this invention is not limited to the following embodiment.

[Secondary battery]
As shown in FIGS. 1 to 4, the secondary battery 10 according to the present invention includes a positive electrode 1, a negative electrode 2, and an electrolytic solution 3. The positive electrode 1 includes a metal as a positive electrode active material, the electrolytic solution 3 includes an electrolyte and a solvent, and the electrolyte further includes an ionic compound MX (M: metal ion material, X: anionic material). In the present specification, “metal” is a term including simple metals and alloys, and those doped with other elements.

  As shown in FIGS. 1 to 4, the secondary battery 10 includes (A) an anionic substance X dissociated from the ionic compound MX and a metal ionic substance Y ionized from the positive electrode active material during charging. By combining with the positive electrode, a compound precipitate YX is generated, and the cationic substance M dissociated from the ionic compound MX is reduced or stored at the negative electrode, whereby a metal precipitate M is generated and (B ) At the time of discharge, the anionic substance X is ionized from the compound precipitate YX and returns to the electrolytic solution, and the metal ion substance Y is dissociated from the compound precipitate YX, and the dissociated metal ion substance Y becomes the positive electrode. The metal ion material M ionized from the metal deposit M returns to the electrolyte solution or returns to the electrolyte solution without being returned to the electrolyte solution. Compound to return to the ionic compound MX. The secondary battery according to the present invention can be charged and discharged by such a new reaction mechanism. A part of the compound precipitate may be dissolved.

  The metal salt compound may be provided as a solid in the secondary battery 10 according to the present invention. For example, before charging, the ionic compound MX of the electrolyte can be provided as a solid metal salt compound. In addition, after charging, a salt of the metal element ionized from the metal of the positive electrode active material and the anion material ionized from the denatured ionic compound MX can be provided as a solid metal salt compound. Furthermore, after discharge, the ionic compound MX of the electrolyte can be provided again as a solid metal salt compound. By providing the metal salt compound involved in the charge / discharge reaction mechanism as a solid, an amount of the metal compound exceeding the solubility of the metal salt compound in the solvent can be involved in the charge / discharge reaction mechanism. Can be improved.

  Hereinafter, the constituent elements of the secondary battery will be described in detail.

(Positive electrode)
The positive electrode 1 may itself serve as both a current collector and an active material, or may be composed of a current collector and an active material of different materials. The positive electrode contains a metal as a positive electrode active material. The standard electrode potential of the metal that is the positive electrode active material is larger than the standard electrode potential of the metal ion material M constituting the ionic compound MX and does not spontaneously elute into the electrolyte solution 3. Preferred examples of such a metal include nickel (Ni) having a standard electrode potential of about −0.25 V, and metals that are nobler than the nickel (standard electrode potential is about −0.25 V or more). Specifically, nickel (Ni, -0.257V), copper (Cu, + 0.340V), silver (Ag, + 0.799V), platinum (Pt, + 1.188V), gold (Au, + 1.520V) Etc. Among these, nickel and copper are preferable from the viewpoint of cost.

  When the positive electrode 1 has a current collector, a current collector made of a material that does not cause an electrode reaction is applied. Examples of such a current collector include metals, conductive polymers, carbon and the like that are more noble than the positive electrode active material. The current collector and the positive electrode active material described above are joined together to form the positive electrode 1. A joining means and a joining aspect are not specifically limited.

  The shape of the positive electrode 1 is not particularly limited, and may be, for example, a plate shape, a sheet shape, or a particle shape. Further, the size and thickness of the positive electrode 1 are not particularly limited. The positive electrode 1 may be porous.

  As shown in FIG. 4, a conductive material 5 may be provided on at least a part or one surface of the positive electrode 1. The conductive material 5 is provided so as to be in contact with the positive electrode 1, and acts as a current collector for complementing that the current collecting function is inferior when most of the positive electrode 1 is used for the reaction. . In particular, it is preferably provided when the metal of the positive electrode 1 is copper or nickel. The conductive substance 5 may be provided on one side of the positive electrode 1 opposite to the electrolyte side, or may be provided on a part of the one side. In particular, from the viewpoint of increasing the field where the electrolytic solution and the metal directly react and playing a role as a current collector, it is preferably provided on one side. In FIG. 4, the conductive material 5 is provided on one surface of the positive electrode 1 by laminating the sheet-like positive electrode 1 and the sheet-like conductive material 5. As another example, although not illustrated, a large number of particles of the positive electrode 1 and a large number of particles of the conductive material 5 are mixed to form a sheet as a whole, so that at least a part of the positive electrode 1 has a conductive material. 5 may be provided.

  Examples of the conductive material 5 include carbon such as acetylene black, ketjen black and graphite, a conductive polymer such as polyaniline, and a metal such as gold. The conductive material 5 is formed by mixing with a solvent such as NMP (N-methyl-2-pyrrolidone) containing a resin binder such as polyvinylidene fluoride to form a conductive paste, and applying the conductive paste to the positive electrode 1. be able to. Examples of the solvent include NMP (N-methyl-2-pyrrolidone), MEK (methyl ethyl ketone), IPA (isopropyl alcohol), water and the like, and all or almost by drying after applying the conductive paste on the positive electrode. Can be volatilized off. Note that the conductive paste may contain a binder component that does not significantly reduce the conductivity, and examples of the binder component include polyvinylidene fluoride, polyethylene oxide, and polyvinyl alcohol.

In the positive electrode 1, at the time of charging, as shown in FIGS. 1 and 2, the positive electrode 1 is configured with an anionic substance X (for example, Cl ⁻ ) dissociated from the ionic compound MX (for example, LiCl) that constitutes the electrolytic solution 3. A metal ion substance Y (for example, Cu ions) ionized from the positive electrode active material is bonded to the positive electrode 1, and a compound precipitate YX (for example, CuCl) is generated on the positive electrode 1. That is, the metal ion substance Y combines with the anionic substance X to generate a compound precipitate YX at the positive electrode, and serves to hold the compound precipitate YX at the positive electrode and maintain the charged state. Therefore, the charged state can be maintained for a long time by the metal ion substance Y. For example, when the metal ion substance Y is Cu and the anion substance X is Cl ions, CuCl (copper chloride) or CuCl ₂ (cupric chloride) is generated on the positive electrode as the compound precipitate YX, and the metal ion substance When Y is Ni and the anionic substance X is Cl ion, NiCl ₂ is formed on the positive electrode 1 as a compound precipitate YX. The generated compound precipitate YX, copper chloride or nickel chloride, is retained as the compound precipitate YX on the positive electrode 1 by the action of copper or nickel, which is the metal ion substance Y, and maintains the charged state. In addition, you may dissolve the one part or all part in the electrolyte solution in the state which is maintaining the charge state, as the copper chloride and nickel chloride which are the compound precipitate YX produced | generated at the positive electrode. Dissolution of the compound precipitate YX in the electrolyte accelerates the discharge reaction.

  On the other hand, at the time of discharge, as shown in FIGS. 1 and 2, an anionic substance X (for example, Cl ions) is generated from the compound precipitate YX (for example, CuCl) that is generated on the positive electrode 1 or returned from the electrolyte to the positive electrode 1. Ionizes and jumps out and returns to the electrolyte 3. Further, the metal ion substance Y is ionized from the compound precipitate YX (for example, CuCl), and the ionized metal ion substance Y (for example, Cu ion) is reduced at the positive electrode 1 to return to the metal (for example, Cu), and the metal precipitate M The ionized metal ion substance M returns to the electrolyte. In the positive electrode 1, a charging reaction and a discharging reaction occur by such a mechanism.

(Negative electrode)
The negative electrode 2 only needs to contain a conductor such as a metal, an allotrope of carbon, or a conductive polymer. The conductor may also serve as a current collector, or a current collector and a conductor made of different materials. (Negative electrode material). The conductor of the negative electrode 2 is preferably a material that does not spontaneously elute into the electrolytic solution 3 and from which the metal ion substance M of the ionic compound MX constituting the electrolytic solution 3 can be deposited. The standard electrode potential of the conductor of the negative electrode 2 is larger than the standard electrode potential of the metal ion substance M constituting the ionic compound MX, and does not spontaneously elute in the electrolytic solution 3. Preferred examples of such a conductor include nickel (Ni) having a standard electrode potential of about −0.25 V and metals that are noble (more than the standard electrode potential of about −0.25 V) than the nickel. Specifically, nickel (Ni, -0.257V), copper (Cu, + 0.340V), silver (Ag, + 0.799V), platinum (Pt, + 1.188V), gold (Au, + 1.520V) Etc. Among these, nickel and copper are preferable from the viewpoint of cost.

  The negative electrode 2 may contain a negative electrode active material for reducing and metallizing the metal ion substance M. Examples of the negative electrode active material include tin and silicon. The action of the negative electrode active material has an advantage that the capacity is high while preventing the metal ion substance M from growing in a dendrite shape, and as a result, a highly safe battery that does not short-circuit can be manufactured. Note that when the metal ion substance M is reduced and metallized, an alloy of the metal ion substance M and the metal constituting the negative electrode 2 may be generated.

  Moreover, the negative electrode 2 may contain a negative electrode active material for storing the metal ion material M. Examples of the negative electrode active material include graphite and lithium titanate. The action of the negative electrode active material has an advantage that the charge / discharge efficiency is high because the metal ion material M does not come into direct contact with the electrolytic solution, and as a result, the cycle characteristics are improved. “Storing” means that the metal ion substance M is not a metal, that is, becomes a compound in an ionic state.

  When the negative electrode 2 has a current collector, a current collector made of a material that does not cause an electrode reaction is applied. Examples of such a current collector include nickel, copper, silver, platinum, and gold. The current collector and the negative electrode material described above are joined together to form the negative electrode 2. A joining means and a joining aspect are not specifically limited.

  The shape of the negative electrode 2 is not particularly limited, and may be, for example, a plate shape, a sheet shape, or a particle shape. Moreover, the magnitude | size and thickness of the negative electrode 2 are not specifically limited, either. The negative electrode 2 may be porous.

  In the negative electrode 2, during charging, as shown in FIGS. 1 and 2, M (for example, Li) is ionized from the ionic compound MX constituting the electrolytic solution 3 into metal ions (for example, Li ions). However, it reduces by the negative electrode 2 and precipitates as a metal precipitate (for example, Li). For example, when the negative electrode 2 is Cu and the metal ion is Li ion, the Li ion is reduced on the Cu electrode to deposit metal lithium, and when the negative electrode 2 is nickel and the metal ion is Li ion, Li ions are reduced by nickel and metallic lithium is deposited. On the other hand, during discharge, a metal precipitate (for example, Li) precipitated on the negative electrode 2 is eluted as a metal ion (for example, Li ion) in the electrolytic solution 2 and ionized from the positive electrode 1 and ejected (for example, Cl ion). ) To return to the ionic compound MX (eg, LiCl). In the negative electrode 2, a charging reaction and a discharging reaction occur by such a mechanism, which is a new reaction mechanism that has not existed before. In addition, you may arrange | position the metal M '(for example, Li) of the same kind as the metal deposit M (for example, Li) with a solid beforehand in the negative electrode before charge. By arranging the metal M ′, it is possible to make up for M ′ when the amount of precipitation of M at the time of charging (particularly during initial charging) is insufficient.

The negative electrode 2 may be provided with an electrolyte as a solid as shown in FIG. Preferred examples of the electrolyte provided as a solid include sodium chloride, potassium chloride, magnesium chloride and the like, and sodium chloride is particularly preferable. These electrolytes are often electrically insulating, and are preferably mixed with a conductive material such as carbon particles. For example, when the secondary battery is configured using an electrolyte in which AlCl ₃ is dissolved in a mixed solvent of propylene carbonate or ethylene carbonate as an electrolyte, the electrolyte (for example, NaCl) on the negative electrode 2 is a metal ion during charging. Na ions, which are the substance M, are deposited as Na on the negative electrode 2, and during discharge, the deposited Na returns to the electrolyte compound MX as NaCl. At the same time, Cl ions, which are anionic substances X, are released into the electrolyte during charging, react with the metal on the positive electrode side to form compound precipitates (for example, CuCl), and dissociate from CuCl during discharge. It is released into the electrolytic solution, reacts with Na, which is the metal ion substance M on the negative electrode side, and returns to sodium chloride. Since the solid electrolyte 4 provided in the negative electrode 2 behaves in this way, it is advantageous in that no dendrite is generated because sodium does not move from the negative electrode, and the safety is improved and the life is improved. Has an effect.

  The solid electrolyte 4 is preferably provided with a thickness of 0.01 mm to 0.5 mm. If the thickness is less than 0.01 mm, it may be too thin to obtain a capacity, and if it exceeds 0.5 mm, the reaction may be slow. The solid electrolyte 4 can be provided on the negative electrode 2 by various film forming means.

(Electrolyte)
The electrolytic solution 3 contains an electrolyte and a solvent. The electrolyte contains an ionic compound MX (M: metal ion substance, X: anion substance). Any ionic compound MX may be used as long as it causes a charge reaction and a discharge reaction of the above mechanism. Examples of the metal ion substance M constituting the ionic compound MX include lithium (Li), sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), aluminum (Al), cobalt (Co), and zinc. Any one selected from (Zn) and the like can be mentioned. Other metal ion materials not listed here may be used as long as they exhibit the same behavior as these metal ion materials M. Examples of the anionic substance X include chlorine (Cl), fluorine (F), bromine (Br), iodine (I), PF ₆ , TFSI (trifluoromethanesulfonylimide), and BF ₄ .

Specific examples of the ionic compound MX include inorganic lithium salts such as LiCl, LiClO ₄ , LiBF ₄ , LiPF ₆ , LiAsF ₆ , and LiBr, LiB (C ₆ H ₅ ) ₄ , LiN (SO ₂ CF ₃ ) ₂ , LiC (SO ₂ CF ₃ ) ₃ , LiOSO ₂ CF ₃ , LiOSO ₂ C ₂ F ₅ , LiOSO ₂ C ₄ F ₉ , LiOSO ₂ C ₅ F ₁₁ , LiOSO ₂ C ₆ F ₁₃ , and LiOSO ₂ C ₇ F ₁₅ The organic lithium salt can be mentioned.

A Lewis acid may be included together with the ionic compound MX. In this case, the Lewis acid becomes a medium for bonding the positive electrode active material ion (Y ion) and the X ion of the ionic compound MX or the anion contained in the Lewis acid, and the ionicity during the charge / discharge reaction. It acts to assist the reaction of compound MX. Examples of the Lewis acid include AlCl ₃ , CuCl, ZnCl _{2 and the} like.

  Examples of the solvent include cyclic esters, chain esters, cyclic ethers, and chain ethers. Specific examples include γ-butyrolactone, cyclohexanone, tetrahydrofuran, crown ether, ethylene carbonate, propylene carbonate, and ethylene glycol dimethyl ether. These solvents may be used alone or in combination of two or more.

  The mixing ratio of the ionic compound MX and the solvent constituting the electrolytic solution 3 is preferably within the range of 30% by mass to 80% by mass of the ionic compound MX when the total amount is 100% by mass. Within this range, good charge / discharge can be realized.

  In addition, you may circulate electrolyte solution like the electrolyte solution which comprises a redox flow battery. By circulating the electrolyte, there is an advantage that the battery capacity and the battery life can be increased. Further, the electrolytic solution may be a gel such as a polymer gel by mixing a gelling agent such as a polymer. Since the fluidity of the gel electrolyte is reduced, it is difficult for the gel electrolyte to ooze out of the outer container or the like, and it is difficult for the positive electrode and the negative electrode to be short-circuited, so that the safety of a battery using the gel electrolyte is improved.

  As shown in FIG. 3, when the electrolyte is a solid electrolyte 4 provided on the negative electrode 2, preferable examples of the electrolyte include aluminum chloride, lithium chloride, and calcium chloride as described above. Particularly preferred is aluminum chloride. In this case, the solvent of the electrolytic solution is preferably propylene carbonate, ethylene carbonate, or diethylene carbonate. Further, the solid electrolyte 4 preferably contains a conductive substance such as carbon or a conductive polymer within a range that does not impede its action, thereby increasing the speed of charging and discharging. There is. Moreover, it is preferable that the electrolyte solution contains the various additives etc. which are added to similar electrolyte solution from a viewpoint of charge / discharge efficiency improvement as needed. FIG. 3 shows an example in which the electrolyte is provided on the negative electrode 2. Although not shown, the solid electrolyte can be provided, for example, on the positive electrode 1, in the electrolytic solution 4, on the separator, on the exterior container, and the like in the same manner as the negative electrode 2. That is, the solid electrolyte may be provided at a location where the solid battery is in contact with the solvent constituting the electrolytic solution inside the secondary battery. In order to shorten the charge / discharge time, the place where the solid electrolyte is arranged is the moving speed of the metal ionic substance constituting the ionic compound MX (M: metal ionic substance, X: anionic substance) of the electrolyte in the solvent. And the rate of movement of the anionic substance in the solvent can be determined. For example, when the moving speed of the metal ion substance in the solvent is slower than the moving speed of the anionic substance in the solvent, the distance between the electrolyte and the negative electrode is shorter than the distance between the electrolyte and the positive electrode. It can be provided at a position in the battery. In addition, when the movement speed of the anionic substance in the solvent is slower than the movement speed of the metal ion substance in the solvent, the distance between the electrolyte and the positive electrode is shorter than the distance between the electrolyte and the negative electrode. It can be provided at a position in the battery.

  The secondary battery 10 according to the present invention is a secondary battery (storage battery) having the above-described new charge / discharge mechanism. As described above, for example, a metal ion salt such as LiCl is dissociated into Li ions and Cl ions. Thus, charging and discharging can be performed. At this time, the metal as a positive electrode active material such as copper works to fix Cl in order to maintain the charged state. The secondary battery 10 operating with this charge / discharge mechanism can be applied to various metal salts, and has the advantages of low cost and high energy density.

(Other configurations)
In the secondary battery 10, the voltage and current may be increased by stacking a plurality of single cell structures composed of the positive electrode 1, the negative electrode 2, and the electrolytic solution 3 described above. For example, a single cell structure can be laminated with a separator interposed therebetween. Specifically, the laminate of the positive electrode 1, the separator (not shown), and the negative electrode 2 may be accommodated in an outer container (not shown) as a plate or wound in a spiral shape. You may accommodate in the exterior container. A lead wire (not shown) is connected to each of the positive electrode 1 and the negative electrode 2. The lead wire connected to the positive electrode 1 is usually connected to the positive electrode terminal of the outer container, and the lead wire connected to the negative electrode 2 is usually connected to the negative electrode terminal of the outer container.

  The separator has a function of separating the positive electrode 1 and the negative electrode 2, and the separator is not particularly limited, and a conventionally known separator can be appropriately selected and used in the field of secondary batteries. In addition, a separator is not essential, for example, it can also be used by using a gel-like electrolyte solution.

  Moreover, you may use the solid electrolyte etc. which are generally used as a diaphragm. Such a diaphragm can prevent a short circuit of the battery, and as a result, has an advantage that safety is improved.

  Hereinafter, the battery according to the present invention will be described in detail with reference to examples. The present invention is not limited to the following examples.

[Example 1]
A bipolar glass beaker cell was assembled. A copper rod (diameter 0.2 mm) was used as the positive electrode, and a copper rod (diameter 0.2 mm) was used as the negative electrode. The electrolyte was prepared in a glove box filled with argon gas. As an electrolyte, 4 parts by mass of LiCl, 2 parts by mass of NN dimethylformamide, 93 parts by mass of EC (ethylene carbonate) and 1 part by mass of PC (propylene carbonate) were prepared, mixed, and stirred. What was heated at 60 degreeC for 1 hour was used. A glass beaker cell was assembled with these positive electrode, negative electrode and electrolyte. The liquid injection operation during cell assembly was also performed in a glove box filled with argon gas.

  The assembled glass beaker cell was subjected to a charge test and a discharge test. The battery was charged to a voltage of 4.8 V under constant current control of 0.8 mA / g with respect to the weight of copper immersed in the electrolytic solution. Thereafter, there was a pause for 300 seconds. Subsequently, the battery was discharged to 0 V under constant current control of 0.8 mA / g. As a result, the battery was charged at a charging voltage of 3.1V and discharged at a discharging voltage of about 2.7V. From the X-ray diffraction (XRD) measurement, the precipitate deposited on the negative electrode upon completion of charging was lithium, and the precipitate deposited on the positive electrode was copper chloride (CuCl). Furthermore, from inductively coupled plasma (IPC) emission measurement, it was confirmed that copper was contained in the electrolyte when charging was completed, indicating that a part of copper chloride was dissolved in the electrolyte. Yes.

[Example 2]
A bipolar glass beaker cell was assembled. A nickel rod (diameter 0.2 mm) was used as the positive electrode, and a nickel rod (diameter 0.2 mm) was used as the negative electrode. The electrolyte was prepared in a glove box filled with argon gas. 2 parts by weight of LiPF6, 79 parts by weight of EC (ethylene carbonate) and 1 part by weight of PC (propylene carbonate) were prepared as an electrolyte solution, mixed, and heated at 60 ° C. for 1 hour with stirring. Using. A glass beaker cell was assembled with these positive electrode, negative electrode and electrolyte. The liquid injection operation during cell assembly was also performed in a glove box filled with argon gas.

  The assembled glass beaker cell was subjected to a charge test and a discharge test. The battery was charged to a voltage of 4.2 V under constant current control of 0.8 mA / g with respect to the weight of copper immersed in the electrolytic solution. Thereafter, there was a pause for 300 seconds. Subsequently, the battery was discharged to 0 V under constant current control of 0.8 mA / g. As a result, the battery was charged at a charging voltage of 3.5V and discharged at a discharging voltage of about 3.3V. From the XRD measurement, the deposit deposited on the negative electrode upon completion of charging was lithium, and the deposit deposited on the positive electrode was nickel chloride. Furthermore, from the IPC luminescence measurement, it was confirmed that nickel was contained in the electrolytic solution at the completion of charging, and this indicates that a part of nickel chloride is dissolved in the electrolytic solution.

[Example 3]
A bipolar glass beaker cell was assembled. A copper rod (diameter 0.2 mm) was used as the positive electrode, and a copper rod (diameter 0.2 mm) was used as the negative electrode. The electrolyte was prepared in the atmosphere. As the electrolytic solution, 90 parts by mass of ZnCl 2 and 10 parts by mass of water were prepared, mixed, and heated at 60 ° C. for 1 hour with stirring. A bipolar beaker cell was assembled with these positive electrode, negative electrode and electrolyte. The liquid injection work during cell assembly was also performed in the atmosphere.

  The assembled glass beaker cell was subjected to a charge test and a discharge test. The battery was charged to a voltage of 1.2 V under constant current control of 0.8 mA / g with respect to the weight of copper immersed in the electrolytic solution. Thereafter, there was a pause for 300 seconds. Subsequently, the battery was discharged to 0 V under constant current control of 0.8 mA / g. As a result, the battery was charged at a charging voltage of 0.8V and discharged at a discharging voltage of about 0.6V. From the XRD measurement, the deposit deposited on the negative electrode upon completion of charging was zinc, and the deposit deposited on the positive electrode was copper chloride (CuCl). Further, from the IPC luminescence measurement, it was confirmed that copper was contained in the electrolytic solution at the completion of charging, and this indicates that a part of copper chloride is dissolved in the electrolytic solution.

[Example 4]
A bipolar soft package cell in which NaCl was applied as an electrolyte and copper foil / separator / NaCl-containing film / aluminum foil using a separator was laminated was assembled.

  Specifically, copper foil (thickness 10 μm) was used as the positive electrode, and aluminum foil (thickness 15 μm) was used as the negative electrode. Sodium chloride was used as the electrolyte for the negative electrode. Sodium chloride was applied to the aluminum foil of the negative electrode plate, and the configuration thereof was 80 parts by mass of sodium chloride, 10 parts by mass of graphite, and 10 parts by mass of polyvinylidene fluoride, and the coating amount was 110 g / m 2. A nonwoven fabric (manufactured by Nippon Vilene Co., Ltd., OA-0711) was used as the separator. The electrolyte was prepared in a glove box filled with argon gas. 30 parts by weight of aluminum chloride, 60 parts by weight of triethylene glycol dimethyl ether, and 10 parts by weight of EC (ethylene carbonate) were prepared as electrolytes, mixed, and heated at 60 ° C. for 1 hour with stirring. Was used. A soft package cell was assembled with these positive electrode, negative electrode and electrolyte (copper foil / separator / NaCl-containing film / aluminum foil). The size of the electrode was 4 cm square, the separator was 5 cm square, and the injection volume was 0.5 g. The liquid injection operation during cell assembly was also performed in a glove box filled with argon gas.

  The assembled soft package cell was subjected to a charge test and a discharge test. Charging was performed to a voltage of 4.3 V under a constant current control of 5 mA. Thereafter, there was a pause for 300 seconds. Subsequently, the battery was discharged to 0 V under 5 mA constant current control. As a result, the battery was charged at a charging voltage of 3.1V and discharged at a discharging voltage of about 2.4V. From the XRD measurement, the deposit deposited on the negative electrode upon completion of charging was sodium, and the deposit deposited on the positive electrode was copper chloride (CuCl). Further, sodium chloride was confirmed in the negative electrode at the stage where the subsequent discharge was completed. This indicates that sodium chloride as an electrolyte is separated into sodium and chlorine during charging, and returns to solid sodium chloride during discharging.

[Example 5]
In Example 4, an experiment was performed in the same manner as in Example 4 except that the negative electrode was aluminum, and the positive electrode was Fe (iron foil having a thickness smaller than the potential of the negative electrode metal: 10 μm in thickness).

  The assembled soft package cell was subjected to a charge test and a discharge test. Charging was performed to a voltage of 4.3 V under a constant current control of 5 mA. Thereafter, there was a pause for 300 seconds. Subsequently, the battery was discharged to 0 V under 5 mA constant current control. As a result, the battery was charged at a charging voltage of 2.9V and discharged at a discharging voltage of about 2.1V. From the XRD measurement, the deposit deposited on the negative electrode upon completion of charging was sodium, and the deposit deposited on the positive electrode was iron chloride.

[Example 6]
In Example 4, the negative electrode was made of copper (copper foil: thickness 10 μm), and the positive electrode was made of Fe (the positive electrode was iron foil having a thickness larger than the potential of the negative electrode metal: thickness 10 μm). Experimented.

  The assembled soft package cell was subjected to a charge test and a discharge test. Charging was performed to a voltage of 4.3 V under a constant current control of 5 mA. Thereafter, there was a pause for 300 seconds. Subsequently, the battery was discharged to 0 V under 5 mA constant current control. As a result, the battery was charged at a charging voltage of 2.9V and discharged at a discharging voltage of about 2.1V. From the XRD measurement, the deposit deposited on the negative electrode upon completion of charging was sodium, and the deposit deposited on the positive electrode was iron chloride.

[Example 7]
In Example 4, an experiment was performed in the same manner as in Example 4 except that cupronickel (thickness: 100 μm, manufactured by Nilaco Corporation), which is an alloy of copper and nickel, was used instead of the positive electrode copper foil.

  The assembled soft package cell was subjected to a charge test and a discharge test. Charging was performed to a voltage of 4.3 V under a constant current control of 5 mA. Thereafter, there was a pause for 300 seconds. Subsequently, the battery was discharged to 0 V under 5 mA constant current control. As a result, the battery was charged at a charging voltage of 3.1V and discharged at a discharging voltage of about 2.3V. From the XRD measurement, the deposit deposited on the negative electrode upon completion of charging was sodium, and the deposit deposited on the positive electrode was copper chloride (CuCl) and nickel chloride.

[Example 8]
In Example 4, a carbon layer as a current collector was provided on the back surface of the positive electrode copper foil. The film was composed of 80 parts by mass of graphite particles (CGC50, manufactured by Nippon Graphite Co., Ltd.) and 20 parts by mass of polyvinylidene fluoride, and the coating amount was 50 g / m ² . Thus, a soft package cell composed of carbon layer / copper foil / separator / NaCl-containing film / aluminum foil was assembled.

  The assembled soft package cell was subjected to a charge test and a discharge test. Charging was performed to a voltage of 4.3 V under a constant current control of 5 mA. Thereafter, there was a pause for 300 seconds. Subsequently, the battery was discharged to 0 V under 5 mA constant current control. As a result, the battery was charged at a charging voltage of 3.1V and discharged at a discharging voltage of about 2.3V. From the XRD measurement, the deposit deposited on the negative electrode upon completion of charging was sodium, and the deposit deposited on the positive electrode was copper chloride (CuCl).

[Example 9]
In Example 4, an experiment was performed in the same manner as in Example 4 except that magnesium chloride was used instead of sodium chloride as the electrolyte.

  The assembled soft package cell was subjected to a charge test and a discharge test. Charging was performed to a voltage of 4.3 V under a constant current control of 5 mA. Thereafter, there was a pause for 300 seconds. Subsequently, the battery was discharged to 0 V under 5 mA constant current control. As a result, the battery was charged at a charging voltage of 2.5V and discharged at a discharging voltage of about 1.8V. From the XRD measurement, the deposit deposited on the negative electrode upon completion of charging was magnesium, and the deposit deposited on the positive electrode was copper chloride (CuCl).

[Example 10]
In Example 4, an experiment was performed in the same manner as in Example 4 except that lithium fluoride was used instead of sodium chloride as the electrolyte.

  The assembled soft package cell was subjected to a charge test and a discharge test. Charging was performed to a voltage of 4.3 V under a constant current control of 5 mA. Thereafter, there was a pause for 300 seconds. Subsequently, the battery was discharged to 0 V under 5 mA constant current control. As a result, the battery was charged at a charge voltage of 3.3V and discharged at a discharge voltage of about 2.8V. From the XRD measurement, the deposit deposited on the negative electrode upon completion of charging was lithium, and the deposit deposited on the positive electrode was copper chloride (CuCl) and copper fluoride (CuF).

[Example 11]
A bipolar soft package cell comprising a solid electrolyte membrane and one type of electrolyte was assembled. Copper foil (thickness 10 μm) was used as the positive electrode and the negative electrode. Lithium chloride was used as the electrolyte for the negative electrode. Lithium chloride was applied to the copper foil of the negative electrode plate, and the configuration was 80 parts by mass of lithium chloride and 20 parts by mass of polyvinylidene fluoride, and the application amount was 100 g / m 2. Lithium ion conductive ceramic (LICGC, manufactured by OHARA INC.) Was used as a separator. The electrolyte was prepared in a glove box filled with argon gas. As an electrolytic solution, 10 mass parts of lithium chloride, 20 mass parts of aluminum chloride, 30 mass parts of ethylene carbonate, and 40 mass parts of propylene carbonate were prepared, mixed, and heated at 60 ° C. for 1 hour with stirring. A thing was used. A soft package cell was assembled with these positive electrode, negative electrode and electrolyte (copper foil / LICGC / LiCl-containing film / copper foil). The size of the electrode was 4 cm square, the separator was 5 cm square, and the injection volume was 0.5 g. The liquid injection operation during cell assembly was also performed in a glove box filled with argon gas.

  The assembled soft package cell was subjected to a charge test and a discharge test. Charging was performed to a voltage of 4.3 V under a constant current control of 5 mA. Thereafter, there was a pause for 300 seconds. Subsequently, the battery was discharged to 0 V under 5 mA constant current control. As a result, the battery was charged at a charge voltage of 3.3V and discharged at a discharge voltage of about 2.7V. From the XRD measurement, the deposit deposited on the negative electrode upon completion of charging was lithium, and the deposit deposited on the positive electrode was copper chloride (CuCl). Further, from the IPC luminescence measurement, it was confirmed that copper was contained in the electrolytic solution at the completion of charging, which indicates that a part of copper chloride is dissolved in the electrolytic solution.

[Example 12]
A bipolar soft package cell comprising a solid electrolyte membrane and two types of electrolyte was assembled. Copper foil (thickness 10 μm) was used as the positive electrode and the negative electrode. Lithium chloride was used as the electrolyte for the negative electrode. Lithium chloride was applied to the copper foil of the negative electrode plate, and the constitution was 80 parts by mass of lithium chloride and 20 parts by mass of polyvinylidene fluoride, and the application amount was 100 g / m ² . Lithium ion conductive ceramic (LICGC, manufactured by OHARA INC.) Was used as a separator. The electrolyte was prepared in a glove box filled with argon gas. As an electrolyte solution on the negative electrode side, 20 parts by mass of LiPF ₆ , 40 parts by mass of ethylene carbonate, and 40 parts by mass of dimethyl carbonate were prepared, mixed and stirred and heated at 60 ° C. for 1 hour. Moreover, as positive electrode side electrolyte solution, 10 mass parts of lithium chloride, 20 mass parts of aluminum chloride, 30 mass parts of ethylene carbonate, and 40 mass parts of propylene carbonate were each prepared, they were mixed, and it stirred at 60 degreeC. What was heated for 1 hour was used. A soft package cell is assembled with these positive electrode, negative electrode, and electrolyte solution. At that time, the electrolyte solution is dropped directly on the electrode so as to be wet, so that the positive electrode side electrolyte solution and the negative electrode side electrolyte solution are not mixed. (Copper foil / LICGC / LiCl-containing film / copper foil). The size of the electrode was 4 cm square, the separator was 5 cm square, and the injection volume was 0.5 g. The liquid injection operation during cell assembly was also performed in a glove box filled with argon gas.

  The assembled soft package cell was subjected to a charge test and a discharge test. Charging was performed to a voltage of 4.3 V under a constant current control of 5 mA. Thereafter, there was a pause for 300 seconds. Subsequently, the battery was discharged to 0 V under 5 mA constant current control. As a result, the battery was charged at a charge voltage of 3.3V and discharged at a discharge voltage of about 2.7V. From the XRD measurement, the deposit deposited on the negative electrode upon completion of charging was lithium, and the deposit deposited on the positive electrode was copper chloride (CuCl). Moreover, it was confirmed from the IPC luminescence measurement that copper was contained in the positive electrode side electrolytic solution at the time of completion of charging, which indicates that a part of copper chloride is dissolved in the positive electrode side electrolytic solution. .

[Example 13]
A bipolar soft package cell using graphite as the negative electrode active material was assembled. Copper foil (thickness 10 μm) was used as the positive electrode and the negative electrode. On the copper foil of the negative electrode, a negative electrode active material layer composed of 90 parts by mass of graphite and 10 parts by mass of polyvinylidene fluoride was applied so as to be 100 g / m ² . Further, a film composed of 80 parts by mass of lithium chloride and 20 parts by mass of polyvinylidene fluoride was applied thereon so as to give 100 g / m ² . A nonwoven fabric was used as a separator. The electrolyte was prepared in a glove box filled with argon gas. As an electrolytic solution, 10 mass parts of lithium chloride, 20 mass parts of aluminum chloride, 40 mass parts of ethylene carbonate, and 30 mass parts of propylene carbonate were prepared, mixed, and heated at 60 ° C. for 1 hour with stirring. A thing was used. A soft package cell was assembled with these positive electrode, negative electrode and electrolyte (copper foil / graphite layer / LiCl-containing film / nonwoven fabric / copper foil). The size of the electrode was 4 cm square, the separator was 5 cm square, and the injection volume was 3 g. The liquid injection operation during cell assembly was also performed in a glove box filled with argon gas.

  The assembled soft package cell was subjected to a charge test and a discharge test. Charging was performed to a voltage of 4.3 V under a constant current control of 5 mA. Thereafter, there was a pause for 300 seconds. Subsequently, the battery was discharged to 0 V under 5 mA constant current control. As a result, the battery was charged at a charging voltage of 2.7V and discharged at a discharging voltage of about 2.0V. From the XRD measurement, the deposit deposited on the positive electrode upon completion of charging was copper chloride (CuCl).

[Example 14]
In Example 13, an experiment was performed in the same manner as in Example 13 except that metal silicon particles were used as the negative electrode active material.

  The assembled soft package cell was subjected to a charge test and a discharge test. Charging was performed to a voltage of 4.3 V under a constant current control of 5 mA. Thereafter, there was a pause for 300 seconds. Subsequently, the battery was discharged to 0 V under 5 mA constant current control. As a result, the battery was charged at a charging voltage of 2.9V and discharged at a discharging voltage of about 2.2V. From the XRD measurement, the deposit deposited on the positive electrode upon completion of charging was copper chloride (CuCl).

[Example 15]
In Example 13, the experiment was performed in the same manner as in Example 13 except that lithium titanate particles were used as the negative electrode active material.

  The assembled soft package cell was subjected to a charge test and a discharge test. Charging was performed to a voltage of 4.0 V under a constant current control of 5 mA. Thereafter, there was a pause for 300 seconds. Subsequently, the battery was discharged to 0 V under 5 mA constant current control. As a result, the battery was charged at a charging voltage of 1.8V and discharged at a discharging voltage of about 1.2V. From the XRD measurement, the deposit deposited on the positive electrode upon completion of charging was copper chloride (CuCl).

[Example 16]
A bipolar soft package cell in which LiCl was applied as an electrolyte and a copper foil using a separator / separator / LiCl-containing film / copper foil was laminated was assembled.

  Specifically, a copper foil (thickness 10 μm) was used as the positive electrode, and a copper foil (thickness 10 μm) was used as the negative electrode. Lithium chloride was used as the electrolyte for the negative electrode. Lithium chloride was applied to the copper foil of the negative electrode plate, and the constitution was 80 parts by mass of lithium chloride and 20 parts by mass of polyvinylidene fluoride, and the application amount was 110 g / m 2. A nonwoven fabric (manufactured by Nippon Vilene Co., Ltd., OA-0711) was used as the separator. The electrolyte was prepared in a glove box filled with argon gas. 30 parts by weight of aluminum chloride, 30 parts by weight of triethylene glycol dimethyl ether and 40 parts by weight of EC (ethylene carbonate) were prepared as electrolytes, mixed, and heated at 60 ° C. for 1 hour with stirring. Was used. A soft package cell was assembled with these positive electrode, negative electrode and electrolyte (copper foil / separator / LiCl-containing film / copper foil). The size of the electrode was 4 cm square, the separator was 5 cm square, and the injection volume was 0.2 g. The liquid injection operation during cell assembly was also performed in a glove box filled with argon gas.

  The assembled soft package cell was subjected to a charge test and a discharge test. Charging was performed to a voltage of 4.3 V under a constant current control of 5 mA. Thereafter, there was a pause for 300 seconds. Subsequently, the battery was discharged to 0 V under 5 mA constant current control. As a result, the battery was charged at a charging voltage of 3.1V and discharged at a discharging voltage of about 2.4V. From the XRD measurement, the deposit deposited on the negative electrode upon completion of charging was lithium, and the deposit deposited on the positive electrode was copper chloride (CuCl). When the subsequent discharge was completed, lithium chloride was confirmed on both sides of the separator. This indicates that lithium chloride as an electrolyte is separated into lithium and chlorine during charging, and returns to solid lithium chloride during discharging.

[Example 17]
An experiment was performed in the same manner as in Example 16 except that a Li ion conductive polymer was used instead of the separator, and a porous film coated with copper particles was used instead of the positive electrode copper foil.

As a Li ion conducting polymer, 10 parts by weight of LiTFSI salt and 90 parts by weight of polyvinylidene fluoride were completely dissolved in cyclopentanone. This was applied onto a release PET film so that the film thickness after drying was 50 μm, and dried at 100 ° C. for 1 hour. It peeled from the release pet film and was set as the Li ion conductive polymer.
Further, copper oxide was heated at 500 ° C. for 1 hour in a hydrogen gas atmosphere to obtain copper powder. The copper powder was applied to the graphoil so that the copper powder was 90 parts by weight and the polyvinylidene fluoride was 10 parts by weight to obtain a porous film made of copper.

  The assembled soft package cell was subjected to a charge test and a discharge test. Charging was performed to a voltage of 4.3 V under a constant current control of 5 mA. Thereafter, there was a pause for 300 seconds. Subsequently, the battery was discharged to 0 V under 5 mA constant current control. As a result, the battery was charged at a charging voltage of 3.1V and discharged at a discharging voltage of about 2.4V. From the XRD measurement, the deposit deposited on the negative electrode upon completion of charging was lithium, and the deposit deposited on the positive electrode was copper chloride (CuCl). When the subsequent discharge was completed, lithium chloride was confirmed on both sides of the separator. This indicates that lithium chloride as an electrolyte is separated into lithium and chlorine during charging, and returns to solid lithium chloride during discharging.

DESCRIPTION OF SYMBOLS 1 Positive electrode 2 Negative electrode 3 Electrolytic solution 4 Solid electrolyte 5 Conductive substance 10 Secondary battery

Claims (3)

A positive electrode containing a metal as a positive electrode active material, a negative electrode, and an electrolyte solution,
The electrolyte includes an electrolyte and a solvent;
The electrolyte includes an ionic compound that ionizes into a metal ion material and an anion material ;
A metal salt compound that ionizes into a metal ion substance and an anion substance is provided in a solid state on the negative electrode ,
(A) During charging,
As the anion substance in the electrolyte and the metal ion substance ionized from the positive electrode active material are combined at the positive electrode, a compound precipitate is generated,
A metal ion substance ionized from the metal salt compound provided in a solid state on the negative electrode is reduced in the negative electrode, whereby a metal precipitate is generated in a solid state on the negative electrode,
(B) During discharge,
The anion substance is ionized from the compound precipitate and returned to the electrolyte solution, and the metal ion substance is ionized from the compound precipitate, and the ionized metal ion substance is reduced to the metal by the positive electrode. As we return,
The metal ion substance ionized from the metal precipitate returns to the metal salt compound in a solid state on the negative electrode,
A secondary battery characterized by that. The negative electrode includes a conductor, and the standard electrode potential of the metal of the positive electrode active material and the standard electrode potential of the conductor of the negative electrode are compared with the standard electrode potential of the metal ion material constituting the ionic compound . The secondary battery according to claim 1, which is large. Metal ion material constituting the ionic compound is any one of lithium, sodium, potassium, magnesium is selected from calcium and aluminum, the secondary battery of claim 1.

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