JP2012195100A - Molten salt battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a molten salt battery in which a reduction in charge capacity can be suppressed before and after solidification of an electrolyte.SOLUTION: The molten salt battery includes a cathode active material 2, a conductive assistant 3, a current collector 5, and a binder 4. Conductive fibers are used as the conductive assistant 3. The length of the conductive fibers is 0.1 μm or more. For example, carbon fibers (conductive fibers) having a length of 0.1-50 μm are used as the conductive assistant 3.

Description

  The present invention relates to a molten salt battery that can be charged and discharged.

  As a molten salt battery, for example, a battery described in Patent Document 1 is known. In the sodium-sulfur battery, sodium is used as the negative electrode active material, and sulfur is used as the positive electrode active material. When charging / discharging the battery, it is heated to 300 ° C. or higher.

JP 2000-030738 A

  By the way, since the operating temperature of a sodium sulfur battery is high, the molten salt battery which operate | moves at a comparatively low temperature is researched. The positive electrode of this type of molten salt battery includes a positive electrode active material, a conductive auxiliary agent, a current collector, and a binder, and collects electrons generated in the positive electrode active material through the conductive auxiliary agent on the current collector. When charging and discharging, the molten salt battery is heated to the melting point or higher of the molten salt. Stop heating when not using a molten salt battery. Usually, once the molten salt is heated, the temperature of the molten salt is maintained at a predetermined temperature. For example, when charging / discharging is not performed from the viewpoint of energy saving or the like, heating of the molten salt is stopped. When the molten salt battery was evaluated for such usage, it was found that the charge capacity after solidification of the molten salt was smaller than the charge capacity of the molten salt battery before solidification.

  This invention is made | formed in view of such a situation, The objective is to provide the molten salt battery which can suppress the fall of charge capacity before and after solidification of electrolyte.

In the following, means for achieving the above object and its effects are described.
(1) The invention described in claim 1 is a positive electrode active material, a conductive auxiliary agent that transmits electrons of the positive electrode active material, a current collector that collects the electrons, the positive electrode active material, and the conductive auxiliary agent. A molten salt battery including a molten salt as an electrolyte, wherein at least a part of the conductive auxiliary agent is a conductive fiber.

  The conductive auxiliary agent is interposed between the positive electrode active material and the current collector to form a conductive path that electrically connects the two. Thereby, electrons are moved from the positive electrode active material to the current collector. When a particulate or powdery conductive aid is used, a number of conductive aids are continuously connected to form a conductive path through which electrons move between the positive electrode active material and the current collector. Such a conductive path has a large number of contacts.

  In the case of a molten salt battery having such a positive electrode, the charge capacity decreases before and after the electrolyte is solidified due to the solidification of the electrolyte. This is because the conductive assistants are separated from each other at the contact portion of the conductive path due to the solidification of the electrolyte or the liquefaction of the electrolyte after the solidification, and the separation does not return to the original contact state even by the liquefaction of the electrolyte. . When the connection between the conductive assistants is cut, the path for electrically connecting the positive electrode active material and the current collector is reduced, and the internal resistance of the positive electrode is increased. Thereby, the charge capacity of the molten salt battery is reduced.

  In addition, it is considered as follows that there is no restoration | recovery of the conduction path | route by the re-contact of conduction assistants. In other words, the reason why the conductive assistants do not reconnect in the same state as the connection state before solidification is considered that the electrolyte enters the separated portion when the conductive assistants are separated at the contact points of the conductive path. It is done.

  On the other hand, in the positive electrode having the above configuration, by using conductive fibers as the conductive auxiliary agent, the conductive auxiliary agents in the conductive path can be compared with those using a granular or powdery conductive agent as the conductive auxiliary agent. The number of contacts is reduced. For this reason, the cutting | disconnection by the conductive path by solidification of electrolyte can be suppressed. As a result, a reduction in charge capacity before and after solidification of the electrolyte can be suppressed.

(2) The invention according to claim 2 is characterized in that, in the molten salt battery according to claim 1, the length of the conductive fiber is 0.1 μm or more and 50 μm or less.
When the length of the conductive fiber is less than 0.1 μm, the effect of suppressing the decrease in charge capacity before and after solidification of the electrolyte hardly occurs. In this regard, in the present invention, in order to achieve the above-described configuration, the effect of suppressing the decrease in charge capacity before and after solidification of the electrolyte is made larger than that in the configuration in which the length of the conductive fiber is less than 0.1 μm. Can do.

  On the other hand, when the length of the conductive fiber exceeds 50 μm, the density of the conductive fiber varies in the manufacturing process of the positive electrode, and a portion where contact with the positive electrode active material is reduced is formed. Variation occurs. In this respect, in the above configuration, since the length of the conductive fiber is 50 μm or less, the internal resistance of the positive electrode can be made uniform as compared with the positive electrode formed using the conductive fiber larger than 50 μm.

  Moreover, when a conductive fiber exceeds 50 micrometers, the problem that the short circuit between a positive electrode and a negative electrode will occur easily will also generate | occur | produce. In particular, when the current collector thickness is in the range of 50 μm to 200 μm to increase the capacity density, the conductive fibers protruding from the positive electrode may reach the negative electrode beyond the separator, causing a short circuit. Cheap. By setting the length of the conductive additive to 50 μm or less, a short circuit between the positive electrode and the negative electrode can be suppressed.

  Further, the conductive fiber is preferably 1.0 μm or more and 50 μm or less. In this case, since the number of contacts in the conductive path can be reduced compared to the case of using conductive fibers having a conductive auxiliary agent length of less than 1.0 μm, the effect of suppressing the decrease in charge capacity before and after the solidification of the electrolyte is obtained. Can be larger.

(3) The invention according to claim 3 is the molten salt battery according to claim 1 or 2, wherein the molten salt has a melting point of room temperature or higher.
In general, a molten salt battery has a longer life than a lithium secondary battery having a conventional structure. This point will be briefly described below.

  In the lithium secondary battery, an organic electrolyte, a polymer electrolyte, and an ionic liquid (for example, an electrolyte mainly composed of an organic molecular salt and having a lithium salt dissolved in a molten salt at room temperature) are used as an electrolyte. The problem with this type of secondary battery is that the battery life is relatively short due to the lack of electrochemical stability of the electrolyte. That is, the organic electrolyte easily deteriorates due to a strong oxidation reaction of the positive electrode active material and a strong reduction action on the surface of the negative electrode active material, and decomposes at the interface of the active material, thereby making the active material high resistance. This causes a decrease in battery life. In contrast, a molten salt containing inorganic molecules as a main component is not easily deteriorated by a strong oxidation reaction of the positive electrode active material or a strong reduction action on the surface of the negative electrode active material, and is electrochemically stable in the electrolyte. Therefore, in the molten salt battery, the cycle life of the battery and stability in long-term use are ensured.

  However, in a molten salt battery in which the melting point of the electrolyte is room temperature or higher, it is assumed that solidification and melting of the electrolyte are frequently repeated depending on the usage environment or usage method. In this case, the battery life may be shortened for the above reason. That is, the cycle resistance of the molten salt battery and the stability in long-term use may be impaired.

  In this regard, when the configuration of the present invention is applied to a molten salt battery, it is possible to suppress a decrease in charge capacity caused by solidification of the electrolyte, so that the battery life of the molten salt battery and stability in long-term use are maintained. be able to.

(4) The invention according to claim 4 is the molten salt battery according to any one of claims 1 to 3, wherein R1 and R2 each independently represent fluorine or a fluoroalkyl group. The gist of the present invention is a salt containing an anion of N (SO ₂ R 1) (SO ₂ R 2) and at least one cation of an alkali metal and an alkaline earth metal.

  Since the melting temperature of this type of molten salt is 250 ° C. or less, the operating temperature of the molten salt battery can be lowered. In addition, since the difference between the melting temperature of the molten salt and the operating temperature is small compared to other molten salts, it is possible to suppress a decrease in the life of the molten salt battery.

  (5) The invention according to claim 5 is the molten salt battery according to any one of claims 1 to 4, wherein the current collector has a thickness of 50 μm to 200 μm and a pore diameter of 10 μm. The gist is that the conductive porous sheet has a thickness of 50 μm or less.

  According to the present invention, since the positive electrode active material can be filled in the pores, the distance between the positive electrode active material and the current collector can be limited within a predetermined distance. Furthermore, since the size of the pores and the length of the conductive auxiliary agent are set within substantially the same range, the number of contacts in the conductive path between the positive electrode active material and the current collector can be limited. That is, the number of contacts per unit volume can be reduced, and the cutting rate of the conductive path before and after solidification of the electrolyte can be reduced. Thereby, the suppression effect of the charge capacity fall before and behind solidification of electrolyte can be enlarged further.

  According to the present invention, there is provided a molten salt battery that can suppress a decrease in charge capacity before and after solidification of an electrolyte.

Sectional drawing which shows the cross-sectional structure about the positive electrode of this embodiment. Sectional drawing which shows the cross-sectional structure about the positive electrode of a comparison structure. The schematic diagram which shows a conductive path typically about the positive electrode of this embodiment, and the positive electrode of a comparative structure. The table which shows the charge capacity before and behind a test about an Example and a comparative example.

An embodiment of the present invention will be described with reference to FIGS.
Hereinafter, the configuration of the molten salt battery will be described.
The molten salt battery includes a positive electrode, a negative electrode, a separator disposed between the positive electrode and the negative electrode, and a storage case that stores the positive electrode, the negative electrode, and the separator. The storage case is filled with molten salt.

  The housing case includes a positive electrode case connected to the positive electrode, a negative electrode case connected to the negative electrode, a sealing member that seals between the positive electrode case and the negative electrode case, and a leaf spring that presses the negative electrode in the direction of the positive electrode It is comprised by. The sealing member is formed of a fluorine-based elastic member. The positive electrode case and the negative electrode case are formed of an aluminum alloy.

  As the molten salt, for example, a salt containing an anion (hereinafter “FSA”) represented by the following formula (1), a sodium cation and a potassium cation (hereinafter NaFSA-KFSA) is used. The composition ratio of NaFSA and KFSA is 45 mol% and 55 mol%. With such a composition, the melting point of NaFSA-KFSA is about 57 ° C.

R1 and R2 each represent F (fluorine). In addition, it can replace with this molten salt and can also use as R <1> and R <2> two groups arbitrarily selected from the group comprised by F and a fluoroalkyl group as molten salt. Examples of the molten salt include a salt in which R1 and R2 are substituted with CF3 in the above formula (1) (hereinafter “TFSA”) or a salt in which R1 is F and R2 is substituted with CF3. Moreover, the molten salt containing the some anion selected from the group which substituted R1 and R2 in said Formula (1) with F or a fluoroalkyl group independently is mentioned.

  Moreover, it is not limited to the molten salt which uses Na or K as a cation. The molten salt can be constituted with one or more selected from the group consisting of alkali metals and alkaline earth metals as cations.

The alkali metal can be selected from Li, Na, K, Rb and cesium Cs. The alkaline earth metal is selected from Mg, Ca, Sr and Ba. For example, as a single salt of a molten salt using FSA as an anion, LiFSA, NaFSA, KFSA, RbFSA, CsFSA, Mg (FSA) ₂ , Ca (FSA) ₂ , Sr (FSA) ₂ and Ba (FSA) ₂ can be mentioned. It is done. Moreover, these mixtures can be used as molten salt.

Examples of the molten salt having TFSA as an anion include LiTFSA, NaTFSA, KTFSA, RbTFSA, CsTFSA, Mg (TFSA) ₂ , Ca (TFSA) ₂ , Sr (TFSA) ₂ and Ba (TFSA) ₂ . These mixtures are also used as the molten salt of the molten salt battery.

  For example, a Sn—Na alloy is used as the negative electrode. The core of the negative electrode is Sn, and the surface is a Sn—Na alloy. The Sn—Na alloy is formed by depositing Na on Sn metal by plating.

  The separator separates both electrodes so that the positive electrode and the negative electrode are not in contact with each other, and allows the molten salt to pass therethrough. Specifically, a glass cloth having a thickness of 200 μm is used as a separator.

The configuration of the positive electrode 1 will be described with reference to FIG.
The positive electrode 1 includes a positive electrode active material 2, a conductive auxiliary agent 3 that transmits electrons generated in the positive electrode active material 2, a current collector 5 that collects electrons, and a binder that combines the positive electrode active material 2 and the conductive auxiliary agent 3. 4 is provided.

As the positive electrode active material 2, a mass of crystal particles of sodium chromite (NaCrO ₂ ) (hereinafter, “crystal particle mass”) is used. The crystal particle lump is formed by a plurality of sodium chromite crystal particles gathered and bonded to each other. The particle size (diameter) of the sodium chromite crystal particles is 0.05 μm to 1.0 μm. The particle size (diameter) of the crystal particle lump is set to a size of 0.1 μm to several tens of μm in the pulverization step of the manufacturing process.

The conductive additive 3, diameter 0.5Nm～70nm, length 1.0Myuemu～50myuemu, carbon fiber (conductive fibers) are used in which the ratio between the diameter and length in 15 to 10 ^5. For example, carbon fiber provided by Showa Denko KK can be used. In addition, as a structure of the conductive support agent 3, it is not limited only to carbon fiber, Acetylene black, Ketjen black, glassy carbon, etc. may be mixed, but content of carbon fiber is at least 50. It is preferable that it is volume% or more.

  As the binder 4, polyvinylidene fluoride is used. Any material that adheres the conductive additive 3 and the positive electrode active material 2 and does not corrode in the molten salt under heating can be used as the binder 4.

  As the current collector 5, an aluminum porous sheet (conductive porous sheet) is used. For example, a porous aluminum sheet having a porosity of 70 to 99% and a pore diameter of 10 μm to 50 μm is used. The thickness is preferably 50 μm or more and 200 μm or less. The pores of the aluminum porous sheet are continuous ventilation holes.

Next, the internal structure of the positive electrode 1 will be described.
The conductive auxiliary agent 3 is interposed between the positive electrode active material 2 and the current collector 5 and electrically connects them. For example, one conductive additive 3 is in contact with the positive electrode active material 2 and the current collector 5 to electrically connect them. The other conductive auxiliary agent 3 connects the positive electrode active material 2 and the current collector 5 via another conductive auxiliary agent 3. Thus, the conductive auxiliary agent 3 connects the positive electrode active material 2 and the current collector 5 with a relatively small number. That is, the conductive path LC formed by the conductive auxiliary agent 3 has a smaller number of contacts between the conductive auxiliary agents 3 in the conductive path LC than the conductive path LC formed by a granular or powdery conductor. For this reason, when this positive electrode is placed under conditions where the solidification and dissolution of the electrolyte are repeated, the cutting frequency of the conductive path LC caused by this condition is the same as that of the positive electrode using a granular or powdery conductive aid. Compared to when placed in

  Moreover, the conductive support agent 3 forms the conductive network which consists of the conductive path | route LC in the pore of an aluminum porous sheet, when the conductive support agents 3 mutually contact, The positive electrode active material in the small space of this conductive network 2 is captured. That is, the conductive assistants 3 are easily entangled. For this reason, when the positive electrode is placed under a condition in which the electrolyte is repeatedly solidified and dissolved, the conductive assistants 3 are more entangled or the conductive assistants are in contact with each other at a portion different from that before solidification. The conductive network is maintained in different forms without reducing the number of contacts. This suppresses a decrease in the number of contacts between the conductive assistants before and after solidification.

Next, a method for manufacturing the positive electrode 1 will be described.
First, a NaCrO ₂ as a positive electrode active material 2, and a conductive additive 3, a binder 4, and an N- methyl-2-pyrrolidone as a solvent, 85 mass ratio: 10: 5: Mix 50 ratio of , Forming a slurry. Next, the aluminum porous sheet is filled with slurry, dried, and then pressed at 1000 kgf / cm ² (9.8 × 10 ⁷ Pa). The positive electrode 1 is formed as described above.

With reference to FIG. 2, the structure of the molten salt battery having a comparative structure will be described.
The molten salt battery having a comparative structure is different from the molten salt battery of the above embodiment in the form of the conductive additive. As the conductive auxiliary agent 30, granular carbon black is used. The size of the carbon black is, for example, 10 nm to 1000 nm as an average diameter.

  In the positive electrode 1 of this type, the conductive path LC is formed by continuously connecting a large number of conductive assistants 30. For this reason, the conductive path LC has a larger number of contacts than the positive electrode 1 of the above embodiment.

With reference to FIG. 3, the positive electrode structure of the embodiment and the positive electrode structure of the comparative molten salt battery are compared.
FIG. 3A shows the conductive path LC in the positive electrode 1 of the embodiment.
The positive electrode active material 2 and the current collector 5 are electrically connected by two conductive assistants 3. That is, in the conductive path LC, there is no portion that is cut by the phase change of the electrolyte immersed in the positive electrode 1, that is, the change from solid to liquid or the change from liquid to solid.

FIG. 3B shows a conductive path LC in the positive electrode of the comparative molten salt battery.
A plurality of conductive assistants 30 are interposed between the positive electrode active material 2 and the current collector 5. And these positive electrode active materials 2 and the electrical power collector 5 are electrically connected by connecting these conductive support agents 30 continuously. In other words, the conductive path LC has a plurality of contacts where the conductive assistants 30 are in contact with each other, as indicated by arrows in FIG. Such a contact may be separated by a phase change of the electrolyte immersed in the positive electrode 1, that is, a change from a solid to a liquid or a change from a liquid to a solid. Then, when the conductive assistants 30 are separated from each other at the contact point, the state is hardly returned to the same state as the original state thereafter.

  With reference to FIG. 4, the change of the charge capacity before and after solidification of an electrolyte is demonstrated about the molten salt battery of embodiment and the molten salt battery of a comparison structure. In addition, an Example is an example of the molten salt battery of embodiment, and a comparative example shows the molten salt battery of a comparative structure.

[Molten salt battery of Example]
The structure of the molten salt battery was the same as that of the molten salt battery shown in the above embodiment.
Positive-electrode active material weight (NaCrO ₂₎ was 1.2 mg / cm ^2.
-The thickness of the positive electrode was 0.05 mm.
-As the conductive auxiliary agent 3, carbon fiber made by Showa Denko KK having an average diameter of 10 nm and an average length of 15 μm was used. About average diameter and average length, it measured about 100 samples arbitrarily selected from the image imaged with the magnification 15000 with the electron microscope, and computed based on these values.

[Mixed salt battery of comparative example]
-The structure of the molten salt battery was the same as that of the molten salt battery shown in the above embodiment, except for the conductive additive.
Positive-electrode active material weight (NaCrO ₂₎ was 1.2 mg / cm ^2.
-The thickness of the positive electrode was 0.05 mm.
-As the conductive assistant 30, carbon black manufactured by Denki Kagaku Kogyo Co., Ltd. having an average particle size of 35 nm was used. The average particle diameter was measured for 100 samples arbitrarily selected from images taken with an electron microscope at a magnification of 15000, and calculated based on these values.

[Test conditions]
For each sample, the charge capacity was measured at a discharge rate of 0.2 C and a current density of 0.02 mA.
-After measuring the charge capacity before the above test, a heat cycle test was performed under the following conditions. In the heat cycle test, the low temperature condition is 25 ° C., the high temperature condition is 80 ° C., the low temperature maintenance period is 900 minutes, the high temperature maintenance period is 360 minutes, and the cycle that maintains the low temperature condition and then maintains the high temperature condition is one cycle. Perform 50 cycles. Note that the molten salt is in a solid state under a low temperature condition, and the molten salt is in a liquid state under a high temperature condition.
-After the above test, the charge capacity was measured under the same conditions as before the test.

[Test results]
As shown in FIG. 4, the rate of decrease in charge capacity before and after the test in the molten salt battery of the comparative example is 6.6%, whereas the rate of decrease in charge capacity before and after the test in the molten salt battery of the example is 1.3%. In other words, the molten salt battery of the example has a smaller reduction rate of the charge capacity than the molten salt battery of the comparative example.

[Evaluation]
According to the above test, since the electrolyte is solidified and immersed in the electrolyte, the positive electrode 1 repeats expansion and contraction. As a result, a tensile force or a shearing force is applied to the conductive path LC, so that a weak portion in the conductive path LC, that is, a contact point where the conductive assistants 3 are in contact with each other is cut off.

  In the case of the molten salt battery of the comparative example, since there are a large number of contacts in the conductive path LC, there is a high possibility that the conductive path LC is in a disconnected state by the above test. On the other hand, in the case of the molten salt battery of the example, since the number of contacts existing in the conductive path LC is small, the possibility that the conductive path LC is cut by the above test is low. On the other hand, when the conductive path LC is cut, the charge capacity is reduced based on the increase in resistance between the positive electrode 1-electrode active material and the current collector 5. Based on the above, the molten salt battery of the example is considered to have a smaller decrease in charge capacity before and after the test than the molten salt battery of the comparative example. Actually, as shown in the test results, it was confirmed that the molten salt battery of the example had a smaller reduction rate of the charge capacity before and after the test than the molten salt battery of the comparative example.

According to this embodiment, the following effects can be obtained.
(1) In the present embodiment, conductive fibers are used as the conductive auxiliary agent 3. Thereby, since the number of the contacts between the conductive assistants 3 in the conductive path LC can be reduced as compared with those using the granular or powdery conductive assistant 30, the charge capacity before and after solidification of the electrolyte can be reduced. The decrease can be suppressed.

  (2) In the present embodiment, the length of the conductive fiber is 1.0 μm or more and 50 μm or less. According to this configuration, the number of contacts in the conductive path LC can be reduced as compared with the case where conductive fibers having a length of less than 1.0 μm are used. Can be larger.

  In addition, since the dispersion of the conductive fibers in the manufacturing process of the positive electrode 1 can be reduced as compared with the positive electrode 1 formed using conductive fibers larger than 50 μm, the internal resistance is uniform on the surface of the positive electrode 1. can do. Moreover, the short circuit between a positive electrode and a negative electrode can be suppressed by making the length of a conductive fiber into 50 micrometers or less.

  (3) In the present embodiment, a molten salt having a melting point of room temperature or higher is used as the electrolytic solution. In a molten salt battery of a sodium ion conductive electrolyte having a melting point of room temperature (25 ° C.) or higher, the frequency of solidification of the electrolyte may increase depending on the use environment or use method of the battery. In such a case, the effect of adopting conductive fibers as the conductive auxiliary agent 3 is particularly remarkable.

(4) In this embodiment, a salt containing an anion of N (SO ₂ R 1) (SO ₂ R 2) and at least one cation of an alkali metal and an alkaline earth metal is used as the molten salt. Since the melting temperature of this type of molten salt is 250 ° C. or less, the operating temperature of the molten salt battery can be lowered. In addition, since the difference between the melting temperature of the molten salt and the operating temperature is small compared to other molten salts, it is possible to suppress a decrease in the life of the molten salt battery.

  (5) In this embodiment, an aluminum porous sheet having pores of 10 μm or more and 50 μm or less is used as the current collector 5. According to this configuration, the distance between the positive electrode active material 2 and the current collector 5 is limited to a predetermined distance, and the number of contacts in the conductive path LC between the positive electrode active material 2 and the current collector 5 is reduced. Limited. Thereby, since the number of contacts per unit volume can be reduced, the effect of suppressing the decrease in charge capacity before and after solidification of the electrolyte can be further increased.

(Other embodiments)
In addition, embodiment of this invention is not restricted to the aspect shown in the said Example, For example, this can be changed and implemented as shown below. Further, the following modifications are not applied only to the above-described embodiments, and different modifications can be combined with each other.

  -In the said embodiment, although the conductive support agent 3 whose length is 1.0 micrometer-50 micrometers is used, what is shorter than 1.0 micrometer can also be used. Specifically, if the length of the conductive auxiliary agent 3 is 0.1 μm or more, the conductive auxiliary agent 3 before and after solidification of the electrolyte as compared with the positive electrode using conductive particles of less than 0.1 μm as the conductive auxiliary agent. A reduction in charge capacity can be suppressed.

  -Although carbon fiber is mentioned as the conductive support agent 3 in the said embodiment, the form is not limited. For example, the conductive auxiliary agent 3 may be formed by branching conductive fibers or conductive particles strongly connected in a chain shape.

  -In the said embodiment, although the composition of the conductive support agent 3 is made into carbon, it is not limited to carbon, You may include an additive. Also, aluminum fibers can be used as the conductive aid 3. Even with such a configuration, the effect according to the embodiment is achieved.

  -In the said embodiment, although the aluminum porous sheet is used as the electrical power collector 5, it can replace with this and can also use an aluminum unemployed cloth or an aluminum sheet. Even with this configuration, there is an effect according to the above embodiment.

  DESCRIPTION OF SYMBOLS 1 ... Positive electrode, 2 ... Positive electrode active material, 3, 30 ... Conductive auxiliary agent, 4 ... Binder, 5 ... Current collector.

Claims (5)

A positive electrode active material, a conductive auxiliary agent that transmits electrons of the positive electrode active material, a current collector that collects the electrons, and a binder that combines the positive electrode active material and the conductive auxiliary agent, and is melted as an electrolyte. A molten salt battery containing salt,
A molten salt battery, wherein at least a part of the conductive assistant is a conductive fiber. The molten salt battery according to claim 1,
The length of the said conductive fiber is 0.1 micrometer or more and 50 micrometers or less. The molten salt battery characterized by the above-mentioned. The molten salt battery according to claim 1 or 2,
The molten salt battery has a melting point not lower than room temperature. In the molten salt battery as described in any one of Claims 1-3,
In the molten salt, R1 and R2 each independently represent a fluorine or fluoroalkyl group, an anion of N (SO ₂ R1) (SO ₂ R2), and a cation of at least one of an alkali metal and an alkaline earth metal A molten salt battery characterized by comprising: In the molten salt battery as described in any one of Claims 1-4,
The current collector is a conductive porous sheet having a thickness of 50 μm to 200 μm and a pore diameter of 10 μm to 50 μm.

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