JP2010225498A - Organic electrolyte battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic electrolyte battery which uses manganese oxide excellent in reliability under a high-temperature and high-humidity environment as an active material. <P>SOLUTION: The organic electrolyte battery includes: a positive electrode 4; a negative electrode 5 comprising lithium metal, lithium alloy, or a material capable of occluding or releasing lithium; and organic electrolyte. The positive electrode 4 prepared by thermally treating a mixture of manganese oxide being an active material and a conductive agent in the organic solvent containing imidazole and lithium bisperflouro sulfonylimide is used. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a technique for improving storage characteristics of an organic electrolyte battery using manganese oxide for a positive electrode.

A lithium ion secondary battery in which a positive electrode active material is combined with lithium cobalt oxide (LiCoO ₂ ) and a negative electrode is combined with a graphite-based carbon material has been put into practical use and is used as a main power source for small portable devices such as mobile phones. Lithium cobaltate has a problem in cost, and spinel-type lithium manganate (LiMn ₂ O ₄ ), which is an alternative active material candidate, is currently actively studied for practical use by many researchers. Yes.

  However, a secondary battery using spinel type lithium manganate as a positive electrode may be significantly deteriorated in battery performance due to the influence of moisture inside the battery (acid formation) and exposure to a high temperature environment. The deterioration factor is considered to be caused by a combination of a decrease in positive electrode capacity due to dissolution of manganese from the positive electrode and a decrease in negative electrode capacity due to precipitation of dissolved manganese on the negative electrode surface.

Therefore, as a method of suppressing the dissolution reaction of manganese, addition of different metals to lithium manganate, addition of lithium cobaltate and lithium nickelate to lithium manganate, water removal by additives to the organic electrolyte, Various efforts such as coating of the negative electrode surface have been made. Selected from the group consisting of 1-vinylimidazole, vinyl methacrylate, vinyl acetate and derivatives of these compounds in a positive electrode made of spinel type lithium manganate, two or more solvents containing ethylene carbonate and diethyl carbonate in the organic electrolyte There has been proposed a means for suppressing the generation of gas due to the decomposition of the organic electrolyte and improving the high-temperature storage and storage characteristics of the battery by including the polymerizable organic compound (see Patent Document 1).
JP 2000-223154 A

  However, at present, sufficient measures have not been taken to suppress the dissolution reaction of manganese by the acid component formed by the reaction with moisture inside the battery. An object of this invention is to provide the organic electrolyte battery excellent in the storage characteristic by suppressing the manganese dissolution reaction by the acid component formed by reaction with the water | moisture content inside a battery.

  To achieve the above object, the present invention provides an organic electrolyte battery comprising a positive electrode, a negative electrode made of lithium metal, a lithium alloy or a material capable of occluding and releasing lithium, an organic electrolyte, and a separator. It is characterized by comprising a mixture of an active material manganese oxide and a conductive agent that has been heat-treated in an organic solvent containing imidazole and lithium bisperfluorosulfonylimide.

  According to the present invention, the dissolution reaction of manganese by the acid component formed by the reaction with moisture inside the battery can be suppressed, and an organic electrolyte battery with significantly improved long-term storage performance can be obtained.

  The first invention of the present invention is an organic electrolyte battery comprising a positive electrode, a negative electrode made of lithium metal, a lithium alloy or a material capable of occluding and releasing lithium, an organic electrolyte, and a separator. An organic electrolyte battery comprising a mixture of a manganese oxide and a conductive agent that is heat-treated in an organic solvent containing imidazole and lithium bisperfluorosulfonylimide. With the above configuration, the dissolution reaction of manganese due to the acid component formed by the reaction with moisture inside the battery can be suppressed, and an organic electrolyte battery with significantly improved long-term storage performance can be obtained.

  The second invention of the present invention is characterized in that, in the first invention, an organic solvent having a boiling point of 230 ° C. or higher is used. With this configuration, the heat treatment temperature can be set high, so that the effect of suppressing the dissolution reaction of manganese is further enhanced, and an organic electrolyte battery with better long-term storage performance can be obtained.

  The manganese dissolution reaction can be suppressed by heat-treating the manganese oxide, which is the positive electrode active material, and the conductive agent in an organic solvent containing imidazole and lithium bisperfluorosulfonylimide. However, no effect was obtained even if only the manganese oxide of the positive electrode active material was heat-treated in the same manner. Although the detailed reaction mechanism is unknown, it is presumed as follows. The formation of an acid component inside the battery occurs mainly at a three-phase interface between a highly active manganese oxide, a conductive agent and an organic electrolyte, which is a positive electrode active material, in water, an organic electrolyte, and a solute. By coating the surfaces of the manganese oxide and the conductive agent with a film of an imidazole polymer by the heat treatment, it is assumed that the organic electrolyte cannot be in direct contact and the acid formation reaction has not progressed. In fact, manganese oxide has high activity and is generally used as a catalyst. Carbon species as a conductive agent is also used as a standard electrode material. One example is a combination of a product and activated carbon.

  As a heat treatment method, a manganese oxide that is a positive electrode active material and a conductive agent are immersed in an organic solvent in the outside to incorporate a pretreated material into the battery, or by exposing the battery itself to a high temperature after manufacturing the battery. For example, heat treatment may be performed on an electrode made of manganese oxide as a positive electrode active material and a conductive agent inside the battery.

  As heat processing temperature, 150 degreeC or more is preferable. When the temperature is lower than 150 ° C., the thickness of the coating film becomes thin and uneven thickness tends to occur, and the effect of coating by heat treatment may be insufficient. More preferably, it is performed at 180 ° C. or higher. Further, the upper limit temperature of the heat treatment is preferably 270 ° C. or lower.

  It is important to use an organic solvent having a boiling point of 230 ° C. or higher. A low boiling point organic solvent has a high vapor pressure, and the weight loss due to evaporation of the liquid during heat treatment increases. In addition, it is difficult to set the heat treatment temperature high, and the heat treatment effect targeted by the present invention may be insufficient. In addition, since an organic solvent having a high boiling point has high polarity, the solubility of imidazole and lithium bisperfluorosulfonylimide is improved.

  Even if an organic solvent remains in the mixture powder after the heat treatment step, the battery characteristics are not adversely affected and the workability is simplified. Therefore, it is preferable to use an organic solvent species that can also be used as an organic electrolyte for the battery. Are optimal, and propylene carbonate, sulfolane, tetraglyme and the like are preferable.

The concentration of imidazole in the organic solvent is preferably about 0.5 to 5 wt%. If the amount is less than 0.1 wt%, the thickness of the coating covering the surface of the manganese oxide and the conductive agent is completely reduced, and there is a risk of pinhole formation. From the viewpoint of thickness, it is preferably 0.5 wt% or more. Moreover, even if the concentration is higher than 5 wt%, there is no difference in effect, so 5 wt% or less is sufficient. Probably, there seems to be almost no difference in film thickness.

  About the density | concentration of lithium bisperfluoro sulfonylimide, 0.7-1.5 mol / L of the level equivalent to the case where it uses as a solute of an organic electrolyte solution is preferable. When the amount of imidazole is larger than that of lithium bisperfluorosulfonylimide, the reactivity during the heat treatment seems to decrease, and the effect cannot be obtained. Some imidazole compounds have a functional group, but sufficient effects cannot be obtained.

  Hereinafter, preferred embodiments of the present invention will be described. The following embodiment is an example embodying the present invention, and does not limit the technical scope of the present invention.

  FIG. 1 is a cross-sectional structure diagram of a coin-type lithium secondary battery which is an example of an organic electrolyte battery according to an embodiment of the present invention. In addition to the function of insulating the positive electrode can 1 made of stainless steel having excellent corrosion resistance, the negative electrode can 2 made of stainless steel, and the positive electrode can 1 and the negative electrode can 2 together, A gasket 3 is provided for physically sealing the power generation element in the battery container in a liquid crystal manner. The gasket 3 interposed between the positive electrode can 1 and the negative electrode can 2 was made of a polyether ether ketone (PEEK) resin. A solution obtained by diluting butyl rubber with toluene was applied between the gasket 3 and the positive electrode can 1 and between the negative electrode can 2 and the gasket 3, and the toluene was evaporated to form a sealant (not shown) made of a butyl rubber film.

  The positive electrode 4 contains manganese oxide as an active material. The negative electrode 5 is a lithium aluminum alloy. For the separator 6 disposed between the positive electrode 4 and the negative electrode 5, polyphenylene sulfide (PPS) was used. The separator 6 is filled with an organic electrolyte solution (not shown).

As the manganese oxide, manganese dioxide, lithium-containing manganese oxide, or spinel type lithium manganate is used. Manganese dioxide is used as a primary battery material, and γ-MnO ₂ and β-MnO ₂ obtained by heat treatment of electrolytic manganese dioxide at about 350 to 440 ° C. have high solubility, and the effects of the present invention are remarkably obtained. As the lithium-containing manganese oxide, lithiated ramsdellite-type manganese dioxide or orthorhombic Li _0.44 MnO ₂ is used. Spinel lithium manganate is used as a positive electrode material for secondary batteries. As for lithium manganate, Li _{1 + X} Mn _2- XO ₄ (0 ≦ X ≦ 0.33) of three sources of lithium, manganese, and oxygen or Li _{1 + X} Mn in which a part of spinel type manganese is substituted with a different element _2-X-y AO ₄ (A is Cr, Ni, Co, Fe, Al, B, 0 ≦ X ≦ 0.33, 0 <y ≦ 0.25).

  The conductive agent is at least one selected from the group consisting of carbon black, acetylene black, denka black, natural graphite, and artificial graphite. From the viewpoint of conductivity, those having a large specific surface area such as carbon black, acetylene black and denka black are preferred. However, since the three-phase interface between the manganese oxide, the organic electrolyte, and the conductive agent increases, more reactions are likely to occur from the viewpoint of the acid formation reaction. While maintaining conductivity, the acid formation reaction can be suppressed and excellent positive electrode performance can be realized. Moreover, the decomposition reaction of the organic electrolyte solution by the active material and the conductive agent constituting the positive electrode, which is a conventional problem, can also be suppressed.

  As the binder for the positive electrode made of manganese oxide, fluorine-based resins such as polytetrafluoroethylene (PTFE), tetrafluoroethylene, hexafluoropropylene copolymer (FEP), and polyvinylidene fluoride (PVDF) are preferable. .

  The heat treatment is a mixture of the positive electrode active material and the conductive agent, or a mixture powder composed of the positive electrode active material, the conductive agent and the binder, or a pellet formed by molding the mixture powder, or the aluminum of the current collector and the positive electrode active material and the conductive agent. The effect of the present invention can be obtained by applying to an electrode coated with a binder. Moreover, the same effect is acquired also by actually heat-processing with a mixture pellet or a coating electrode, and an organic electrolyte solution after battery formation.

  Negative electrode materials mainly include carbon-based materials such as lithium, natural graphite, artificial graphite and non-graphitizable carbon, lithium alloys such as silicon, aluminum, tin and germanium, silicon monoxide, tin monoxide and cobalt monoxide. An oxide that reacts with metal lithium at 1 V or less, an oxide that reacts with metal lithium such as spinel-type lithium titanium oxide, niobium pentoxide, and tungsten dioxide at 1 V or more, and a negative electrode A spinel type lithium manganese oxide used for the positive electrode can be used.

  Examples of the separator material include olefin polymers such as polypropylene and polyethylene, engineering plastics such as polybutylene terephthalate, polyphenylene sulfide, and polyetheretherketone, and glass separators made of inorganic glass fibers. A separator made of engineering plastic or glass fiber is preferable. As the separator, either a nonwoven fabric or a microporous membrane can be used.

  As the organic electrolytic solution, the organic solvent having a boiling point of 230 ° C. or higher is at least one or more selected from 1,2-dimethoxyethane, diethyl carbonate, dimethyl carbonate, ethyl methyl carbonate, diglyme, triglyme, ethylene carbonate, and the like, which are low boiling solvents. A solution obtained by dissolving 0.7 to 1.5 mol / L of lithium bisperfluorosulfonylimide can be used as a solute in the mixed solvent. Further, 10 to 20 mol% of lithium tetrafluoroborate or lithium hexafluorophosphate may be added to solute lithium bisperfluorosulfonylimide. Moreover, as a density | concentration when adding imidazole to an organic electrolyte solution, 0.5-5 wt% is preferable.

  The shape of the organic electrolyte battery of the present invention can be applied to a coin-type or button-type flat battery, a cylindrical battery, a square battery, an aluminum laminate battery, or the like. In particular, the present invention is more effective for a flat battery or a cylindrical battery with low airtightness that is sealed with a caulking seal, because there is much moisture intrusion into the battery.

  With the above configuration, an organic electrolyte battery using manganese oxide for the positive electrode having excellent storage characteristics can be provided.

  Hereinafter, preferred embodiments of the present invention will be described.

(Experiment 1)
FIG. 1 is a cross-sectional view of a secondary battery having a thickness of 1.4 mm and a diameter of 4.8 mm used in an example of the present invention.

In the positive electrode 4, spinel type lithium manganate obtained by baking lithium hydroxide and manganese dioxide for 10 hours at 600 ° C. is used as a positive electrode active material, carbon black as a conductive agent, and fluororesin powder as a binder: 85: 7 mg mixed at a weight ratio of 7: 8 was molded into pellets having a diameter of 2 mm and a thickness of 0.9 mm, and then dried at 250 ° C. for 12 hours. The obtained pellet-like positive electrode material is in contact with the positive electrode current collector 7 formed by applying a carbon paint on the inner surface of the positive electrode can 1.

  On the other hand, the negative electrode 5 is formed by punching an aluminum sheet into a disk shape having a diameter of 2.5 mm and a thickness of 0.2 mm, pressing the aluminum sheet inside the negative electrode can 2, and subsequently a lithium metal sheet having a thickness of 0.10 mm is φ2.0 mm. This is punched out and crimped to the surface of this aluminum. When the battery is assembled, by injecting the organic electrolyte, lithium and aluminum are short-circuited, and lithium is occluded electrochemically in the aluminum metal. The lithium aluminum alloy obtained by this reaction was used as the negative electrode 5.

  Further, polyphenylene sulfide (PPS) was used for the separator 6 disposed between the positive electrode 4 and the negative electrode 5. Sulfolane (boiling point 286 ° C.): 1,2 dimethoxyethane (boiling point 83 ° C.) mixed at a volume ratio of 90:10 as a solute, 1.2 mol / L lithium bisperfluorosulfonylimide and 1 wt% imidazole were dissolved. The organic electrolyte is filled in a battery container composed of the positive electrode can 1, the negative electrode can 2, and the gasket 3 in a volume of 2.5 μl.

  The organic electrolyte battery thus obtained was designated as battery A according to Example 1. By placing the battery itself at a high temperature, the mixture of manganese oxide, which is a positive electrode active material, and a conductive agent was heat-treated inside the battery in an organic solvent containing imidazole and lithium bisperfluorosulfonylimide.

  About the battery A, the peak temperature at the time of reflow was changed, and it was made to pass through the hot air type reflow furnace. The peak temperatures during reflow are 240 ° C, 220 ° C, 200 ° C, 180 ° C, 150 ° C and 140 ° C. The temperature profile inside the reflow furnace used for the test was exposed to an environment of 140 ° C. for 2 minutes as a preheating process, and subsequently passed through 140 ° C., each peak temperature, and 140 ° C. for 30 seconds as a heating process, and then reached room temperature. Until naturally cooled. This reflow process was passed twice. The batteries after passing through each reflow peak temperature are designated as batteries A, A1, A2, A3, A4, and A5, respectively. Thereafter, charging and discharging were performed at a constant current of 5 μA in the range of 4.0 to 3.0 V, and the initial discharge capacity was examined. After charging the batteries A to A5 to 4.0 V at a constant current of 5 μA, a storage test was performed in a dry atmosphere at 85 ° C. and a high humidity environment at 60 ° C. and 90%. After a storage period of 30 days, the battery was taken out at room temperature and normal humidity, discharged, charged and discharged at a constant current of 5 μA in the range of 4.0 to 3.0 V, and the charge recovery capacity was measured. The capacity was calculated based on 100 as the initial discharge capacity of battery A that passed a peak temperature of 240 ° C. Table 1 shows the results of the initial discharge capacity, the charge recovery capacity after the 85 ° C. storage test and the 60 ° C. 90% storage test.

  When the reflow peak temperature reached 140 ° C., the charge recovery capacity after humid storage was slightly reduced. Above 150 ° C., the charge recovery capacity showed a more stable value.

(Experiment 2)
Instead of the mixed solvent of the organic electrolyte solution of battery A, a battery B having the same configuration except that the volume ratio of tetraglyme (boiling point 275 ° C.) and 1,2 dimethoxyethane (boiling point 83 ° C.) was 90:10 was used. Produced.

  A battery C having the same configuration except that the volume ratio of propylene carbonate (boiling point 242 ° C.) and 1,2 dimethoxyethane (boiling point 83 ° C.) was 90:10 instead of the mixed solvent of the organic electrolyte solution of battery A Produced.

  Instead of the mixed solvent of the organic electrolyte solution of battery A, a battery D having the same configuration except that the volume ratio of butylene carbonate (boiling point 240 ° C.) and 1,2 dimethoxyethane (boiling point 83 ° C.) was 90:10 was used. Produced.

  Battery E having the same structure except that the volume ratio of γ-butyrolactone (boiling point 206 ° C.) and 1,2 dimethoxyethane (boiling point 83 ° C.) is 90:10 instead of the mixed solvent of the organic electrolyte solution of battery A Was made.

  Similarly to Example 1, the batteries B to E were passed twice through a reflow furnace having a peak temperature of 240 ° C. Thereafter, the initial discharge capacity was measured and a storage test was performed in a 85 ° C. dry atmosphere and a 60 ° C. and 90% humid environment. Table 2 shows the results of the initial discharge capacity, the charge recovery capacity after the 85 ° C. storage test and the 60 ° C. 90% storage test.

  In battery E, the deterioration after dry storage and humid storage was slightly larger than batteries A to D. In the batteries A, B, C, and D, the charge recovery capacity value showed a more stable value.

(Experiment 3)
A battery F having the same structure was produced except that the volume ratio of sulfolane (boiling point 286 ° C.) and 1,2 dimethoxyethane (boiling point 83 ° C.) of battery A was changed from 90:10 to 70:30.

  A battery G having the same configuration was prepared except that the volume ratio of sulfolane (boiling point 286 ° C.) and 1,2 dimethoxyethane (boiling point 83 ° C.) of battery A was changed from 90:10 to 50:50.

  A battery H having the same configuration was produced except that the volume ratio of sulfolane (boiling point 286 ° C.) and 1,2 dimethoxyethane (boiling point 83 ° C.) of battery A was changed from 90:10 to 30:70.

  Battery I having the same configuration was produced except that the volume ratio of sulfolane (boiling point 286 ° C.) and 1,2 dimethoxyethane (boiling point 83 ° C.) of battery A was changed from 90:10 to 10:90.

  Similar to Example 1, the batteries A and F to I were passed through a reflow furnace having a peak temperature of 240 ° C. twice. Thereafter, the initial discharge capacity was measured and a storage test was performed in a 85 ° C. dry atmosphere and a 60 ° C. and 90% humid environment. Table 2 shows the results of the initial discharge capacity, the charge recovery capacity after the 85 ° C. storage test and the 60 ° C. 90% storage test.

  In batteries H and I, the deterioration after dry storage and humid storage was slightly larger than batteries A to D. In the batteries A, F, and G, the charge recovery capacity value showed a more stable value.

(Experiment 4)
A battery J having the same configuration was prepared except that the amount of imidazole added to the organic electrolyte of battery A was 0.1 wt%.

  A battery K having the same structure was prepared except that the amount of imidazole added to the organic electrolyte of battery A was 0.5 wt%.

  A battery L having the same configuration was prepared except that the amount of imidazole added to the organic electrolyte of battery A was 3 wt%.

  A battery M having the same configuration was prepared except that the amount of imidazole added to the organic electrolyte of battery A was 5 wt%.

  A battery N having the same configuration was prepared except that the amount of imidazole added to the organic electrolyte of battery A was 10 wt%.

  Comparative battery 1 having the same configuration was prepared except that imidazole of the organic electrolyte solution of battery A was not added.

  Comparative battery 2 having the same configuration except that dimethylimidazole was used as the organic electrolyte of battery A was produced.

  A comparative battery 3 having the same configuration except that imidazole in the organic electrolyte solution of battery A was changed to ethyl imidazole was produced.

  In the same manner as in Example 1, a reflow furnace having a peak temperature of 240 ° C. was passed twice. Thereafter, the initial discharge capacity was measured and stored at 85 ° C. and at 60 ° C. in a 90% humid environment.

  Table 4 shows the results of the initial discharge capacity, the charge recovery capacity after the 85 ° C. storage test and the 60 ° C. 90% storage test.

  In comparative batteries 1 to 3, the charge recovery capacity after dry storage and humid storage was significantly reduced. The charge recovery capacity was more stable at 0.1 wt% or more. In particular, a very high charge recovery capacity was obtained at 0.5 to 5 wt%. Moreover, the effect was not acquired about what has a substituent in imidazole.

(Experiment 5)
A comparative battery 4 having the same structure was prepared except that lithium bisperfluorosulfonylimide, which is the solute of the organic electrolyte solution of battery A, was changed to lithium tetrafluoroborate.

  A comparative battery 5 having the same configuration was prepared except that lithium bisperfluorosulfonylimide, which is the solute of the organic electrolyte solution of battery A, was changed to lithium hexafluorophosphate.

  A comparative battery 6 having the same configuration was prepared except that lithium bisperfluorosulfonylimide, which is the solute of the organic electrolyte solution of battery A, was changed to lithium trifluoromethanesulfonate. In the same manner as in Example 1, a reflow furnace having a peak temperature of 240 ° C. was passed twice. Thereafter, the initial discharge capacity was measured and stored at 85 ° C. and at 60 ° C. in a 90% humid environment. (Table 5) shows the results of the initial discharge capacity, the charge recovery capacity after the 85 ° C. storage test and the 60 ° C. 90% storage test.

  In comparative batteries 4 to 6, the charge recovery capacity after dry storage and humid storage was significantly reduced.

(Experiment 6)
A coin-type primary battery having the same configuration as FIG. 1 and a thickness of 5 mm and a diameter of 24 mm was produced. As the coin-type battery container, a positive electrode can 1 made of stainless steel having excellent corrosion resistance and a stainless steel negative electrode can 2 similar to those in Example 1 were used. The gasket 3 was made of polyphenylene sulfide (PPS) resin. In the same manner as in Example 1, a solution obtained by diluting butyl rubber with toluene was applied between the gasket 3 and the positive electrode can 1 and between the negative electrode can 2 and the gasket 3, and the sealant (not shown) made of a butyl rubber film was evaporated by evaporating the toluene. Formed.

  The positive electrode 4 has a diameter of 2500 mg obtained by mixing electrolytic manganese dioxide (EMD) heat-treated at 350 ° C. with an active material, carbon black as a conductive agent, and fluororesin powder as a binder in a mass ratio of 90: 5: 5. This was formed into a pellet of 18 mm and 3 mm in thickness, and then dried at 50 ° C. for 12 hours. An organic solution in which 1.0 mol / L lithium bisperfluorosulfonylimide and 1 wt% imidazole were dissolved in an organic solvent in which propylene carbonate and methyl diglyme were mixed at a volume ratio of 50:50 was obtained. Heating was performed at 150 ° C., and heat treatment was performed by immersing the positive electrode in the superheated solution for 5 minutes.

  The obtained pellet-like positive electrode material is in contact with the positive electrode current collector 7 formed by applying a carbon paint on the inner surface of the positive electrode can 1. On the other hand, the negative electrode 5 was pressure-bonded to the negative electrode can 2 using metallic lithium having a diameter of 20 mm and a thickness of 1.2 mm. The separator 6 disposed between the positive electrode 4 and the negative electrode 5 was made of polyphenylene sulfide (PPS) resin. 500 μl of an organic electrolyte having the same composition as that used for the heat treatment was used. The organic electrolyte battery thus obtained was designated as a battery K according to Example 4.

A comparative battery 7 having the same configuration as that of the battery K was produced except that the positive electrode of the battery K was not heat-treated.
For battery K and comparative battery 7, 10% capacity was discharged at a constant current of 5 mA with respect to the theoretical capacity of positive electrode manganese dioxide, followed by high-temperature storage, high-temperature and high-humidity storage, and low-temperature discharge. After storing at 100 ° C. for 240 hours as a high temperature storage test, the battery was discharged at a current value of 3 mA in an environment of −40 ° C., and the open circuit voltage (CCV) 1 second after the start of discharge was measured.

  After storing for 240 hours at 85 ° C. and 90% as a high-temperature and high-humidity storage test, the battery was discharged at a current value of 3 mA in an environment of −40 ° C., and the open circuit voltage (CCV) 1 second after the start of discharge was measured.

  The same CCV measurement was performed before the storage test. The results are shown in (Table 6).

  Regarding the battery K of the present invention, there was no extreme decrease in CCV even after high-temperature storage and high-humidity storage, and excellent low-temperature discharge characteristics could be maintained. In Comparative Battery 4 that was not heat-treated, a significant decrease in CCV after high-temperature storage and high-humidity storage was observed.

  Similar effects can be obtained with battery configurations described in the present invention other than those shown in the examples.

  The present invention can provide an organic electrolyte battery having excellent storage performance even when manganese oxide is used for the positive electrode, and is extremely useful industrially.

Sectional drawing of the organic electrolyte battery in one embodiment of this invention

DESCRIPTION OF SYMBOLS 1 Positive electrode can 2 Negative electrode can 3 Gasket 4 Positive electrode 5 Negative electrode 6 Separator 7 Positive electrode collector

Claims (2)

In an organic electrolyte battery comprising a positive electrode, a lithium metal, a lithium alloy or a material capable of occluding and releasing lithium, an organic electrolyte, and a separator, a manganese oxide and a conductive agent as an active material are used as the positive electrode. An organic electrolyte battery characterized by comprising a mixture heat-treated in an organic solvent containing imidazole and lithium bisperfluorosulfonylimide. 2. The organic electrolyte battery according to claim 1, wherein the organic solvent has a boiling point of 230 [deg.] C. or higher.

Images