JPH0521067A - Nonaqueous electrolytic battery - Google Patents

Abstract

PURPOSE:To provide a small type nonaqueous electrolytic battery, the discharging characteristic of which in a 4V region is good and the cycle capacity is not reduced, and which has excellent charging/discharging characteristic. CONSTITUTION:A material expressed as LiMn2-xM'xO4 is used for a positive electrode active material (positive electrode piled pellet 6), while an alkaline metal or its compound is used for a negative electrode active material 4. A material, which is chemically stable to the positive electrode active material as well as the negative electrode active material, and which can move so as to generate electrochemical reaction between alkaline metal ions and the positive electrode active material or the negative electrode active material, is used for an electrolytic material. A small type lithium battery of large reversible capacity and high energy density can thus be formed, and this nonaqueous electrolytic battery can be utilized in various fields such as coin type battery.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a non-aqueous electrolyte battery,
More specifically, the present invention relates to a chargeable / dischargeable non-aqueous electrolyte secondary battery, and particularly to the improvement of the positive electrode active material, with the aim of increasing the charge / discharge capacity of the battery.

[0002]

2. Description of the Related Art Non-aqueous electrolyte batteries using an alkali metal such as lithium or an alloy or compound thereof as a negative electrode active material have a large capacity due to the insertion or intercalation reaction of negative electrode metal ions into the positive electrode active material. It has both discharge capacity and reversibility of charge. Conventionally, as a secondary battery using lithium as a negative electrode active material, a battery using a layered or tunnel oxide such as vanadium pentoxide or manganese dioxide that can be an intercalation host for lithium has been proposed. However, the voltage was low and the charge / discharge energy density was not sufficient. Recently, cubic LiMn with spinel structure
It has been reported that it can be discharged at 4 V when it is initially charged to about 4.5 V with ₂ O ₄ and then discharged (Journal of Electrochemical Society, 1990, Vol. 137, No. 3).
769).

However, in this 4V region, when the composition region of Li / Mn ₂ O ₄ > 1.1 or more is reached due to the progress of discharge, a structural phase transition from cubic to tetragonal occurs, and the discharge voltage corresponding to this occurs. Suddenly drops to 2.8V. Further, this cubic crystal had poor discharge characteristics in the 4V region, and its cycle capacity was halved in less than 50 cycles.

[0004]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a non-aqueous electrolyte battery which is small in size and has battery characteristics which are excellent in charge and discharge characteristics by improving the above problems.

[0005]

In order to achieve such an object, in the non-aqueous electrolyte battery of the present invention, the composition formula: LiMn _{2- x}
A material represented by M ′ _x O 4 (0 <x ≦ 0.7) is included as a positive electrode active material, an alkali metal or a compound thereof is used as a negative electrode active material, and the positive electrode active material and the negative electrode active material are chemically reacted. It is characterized in that the electrolyte material is a material which is stable and is capable of moving alkali metal ions to cause an electrochemical reaction with the positive electrode active material or the negative electrode active material.

Generally, spinel has a composition of AB ₂ O ₄ . Where A is a metal element surrounded by an oxygen tetrahedron, B
Is a metal element surrounded by octahedra of oxygen.

[0007] Positive electrode active material of the present _{invention, LiMn 2-x M 'x} O
₄ is a manganese spinel oxide, Mn located at an octahedral site in LiMn ₂ O ₄ , which is another element ion M'of low oxidation number.
Is a ternary oxide substituted and added, more preferably L
_{iMn 2-x M 'x O} 4 is used to form the dopant M' is a trivalent metal element ions from monovalent. Result of replacement additive by other element ions of Mn ^3+, reduces the abundance ratio of Mn ³⁺ ions with Jahn-Teller instability, stabilized with a wider composition range cubic spinel structure, the charge-discharge characteristics were improved by this it is conceivable that.

[0008] Positive electrode active material in the present invention as described above, 'is shown by _x O _4, such a low oxidation number of the element M' LiMn _2-x M as, for example Al, Sc, F
e, Ni, Co, Mg, V, Y, Zn, Ti, Sb, C
One or more of u and the like can be mentioned.

Further, x is preferably in the range of 0 <x ≦ 0.7. This is because if the doping amount x exceeds 0.7, many other phases may be formed. Particularly preferably 0 <
x ≦ 0.5, and more preferably 0 <x ≦ 0.2.

[0010] This forms a positive electrode using the positive electrode active material, nickel _{LiMn 2-x M 'x O} 4 compound powder and a mixture of polytetrafluoroethylene Gotoki binder powder,
Press-mold on a support such as stainless steel. Alternatively,
In order to impart conductivity to the mixed substance powder, a conductive powder such as pyrolytic graphite or acetylene black is mixed, and a binder powder such as polytetrafluoroethylene is further added thereto, if necessary, and the mixture is mixed. Is placed in a metal container, or the mixture is pressure-molded on a support such as nickel or stainless steel.

Lithium, which is the negative electrode active material, is formed into a sheet shape like that of a general lithium battery, or the sheet is pressure-bonded to a conductor network of nickel, stainless steel or the like to form a negative electrode. As the negative electrode active material, in addition to lithium, conventionally known materials such as lithium alloys and lithium compounds, magnesium, calcium, and sodium can be used.

As the electrolyte, for example, an organic solvent such as dimethoxyethane, 2-methyltetrahydrofuran, ethylene carbonate, methyl formate, dimethylsulfoxide, propylene carbonate, acetonitrile, butyrolactone, dimethylformamide and LiA can be used.
sF ₆ , LiBF ₄ , LiPF ₆ , LiAlCl ₄ , LiC
A non-aqueous electrolyte solution in which a Lewis acid such as 10 ₄ is dissolved can be used.

Further, conventionally known materials can be used for other elements such as a separator and a structural material (battery case, etc.), and there is no particular limitation.

[0014]

EXAMPLES The method of the present invention will be described in more detail with reference to the following examples, which should not be construed as limiting the invention thereto. In the examples, the production and measurement of batteries were performed in a dry box under an argon atmosphere.

[0015]

EXAMPLE 1 FIG. 1 is a cross-sectional view of a coin-type battery which is one specific example of the battery according to the present invention, in which 1 is a stainless steel sealing plate, 2 is a polypropylene gasket, 3 is a positive electrode case made of stainless steel, 4 Is a lithium negative electrode, 5 is a polypropylene microporous separator, and 6 is a positive electrode material mixture pellet.

The positive electrode active material was prepared by substituting various metal elements shown in Table 1 as dopants for substitution and addition of Mn with respect to unsubstituted LiMn ₂ O ₄ , fixing the dope amount to x = 0.5 and weighing and mixing. In addition, a ternary compound oxide crystal powder obtained by heating at 650 ° C. for about 6 hours in the air and further firing at 850 ° C. for 24 hours was used.

Among the obtained powder samples, as an example, Li
Mn _1.5 Mg _0.5 O ₄ , LiMn _1.5 Zn _0.5 O ₄ , LiMn
The X-ray diffraction patterns of _1.5 Ni _0.5 O ₄ are shown in FIGS. 2a-4b. All the peaks are in good agreement with each profile of ASTM, and the main peak of LiMn ₂ O ₄ remains, so that at least up to this composition, there is no substitution of LiM.
It can be seen that Mn is replaced with the added metal element in a solid solution state while maintaining the n ₂ O ₄ spinel structure.

The obtained LiMn _1.5 M _'0.5 O ₄ crystals a conductive agent (acetylene black powder) with a binder (polytetrafluoroethylene), 70: 25: on the mixed in a weight ratio of 5, and roll forming The positive electrode material mixture pellet 6 (thickness 0.5 mm, diameter 17 mm, 200 mg / ce 11) was used. First, the metallic lithium negative electrode 4 placed under pressure on the sealing plate 1 is inserted into the concave portion of the gasket 2, and the separator 5 and the positive electrode material mixture pellet 6 are arranged in this order on the metallic lithium negative electrode 4 to form the electrolyte solution. As an appropriate amount of 1N solution of LiClO ₄ dissolved in an equal volume mixed solvent of propylene carbonate (PC) and 2-dimethoxyethane (DME), respectively, is injected and impregnated, the positive electrode case 3 is covered and caulked. A coin-type battery having a thickness of 2 mm and a diameter of 23 mm was produced.

0.5 mA of the battery thus produced
Table 1 shows the cell discharge capacities up to each cutoff voltage at a discharge current density of / cm ² .

[0020]

[Table 1]

[0021] LiMn is in LiMn _1.5 M _'0.5 O _4
1.5 Al _0.5 O ₄ , LiMn _1.5 Sc _0.5 O ₄ , LiMn _1.5
Fe _0.5 O ₄ , LiMn _1.5 Ni _0.5 O ₄ , LiMn _1.5 Co
_0.5 O ₄ is a system having a relatively large discharge capacity in the high voltage portion of 4V.

[0022]

Example 2 As for the positive electrode active material, x = 0.05 to 0.7 with respect to unsubstituted LiMn ₂ O ₄ with Fe ³⁺ as a dopant.
The ternary compound oxide crystal powder obtained by weighing and mixing the dope amount as shown in the following formula, heating at 650 ° C. for about 6 hours in the air, and then firing at 850 ° C. for 24 hours was used.

Li ₂ CO ₃ + (2-x) Mn ₂ O ₃ + xFe
Advantages over _{2 O 3 + 0.5O 2 → 2LiMn} 2-x Fe x O 4 spinel is particularly pronounced when a large current discharge 3mA / cm ^2.

[0024]

[Example 3] The positive electrode active material was prepared by fixing the dope amount to unsubstituted LiMn ₂ O ₄ at x = 0.01, weighing and mixing various low oxidation number metal elements as dopants, and then mixing at 650 ° C.
After heating in the air for about 6 hours and further firing at 850 ° C. for 24 hours, a ternary compound oxide crystal powder was used.

The positive electrode active material, except using _{LiMn 2-x M 'x O} 4 was synthesized as described above, to produce a lithium battery in the same manner as in Example 1.

As an example, FIGS. 8a to 8d show discharge curves of the battery thus manufactured up to a final voltage of 3.5 V at a discharge current density of 3 mA / cm ² . FIG. 8a is a discharge curve of LiMn ₂ O ₄ of a comparative example, and FIGS. 8b to 8d are discharge curves of Ni, Co, and Fe at x = 0.1.

Similar to LiMn _1.9 Fe _0.1 O ₄ , Co, N
When i, Al, Mg, and Sc were added, the superiority was remarkable over the unsubstituted LiMn ₂ O ₄ spinel in terms of discharge capacity and overvoltage. In any case, it is considered that the addition of these low oxidation number ions reduced the abundance ratio of Mn ^{3+ having} Yanteller instability, which led to the improvement of the characteristics, and the addition of other low oxidation number ions had the same effect. Can be expected. The doping amount is 0 <x ≦ 0.
5, especially, the case of 0 <x ≦ 0.2 is particularly preferable.

[0028]

As described above, according to the present invention,
It is possible to construct a small-sized and high-energy-density lithium battery having a large reversible capacity, and the battery of the present invention has an advantage that it can be used in various fields such as a coin battery.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration example of a coin battery which is an embodiment of the present invention.

FIG. 2a is an embodiment of the present invention LiMn _1.5 Mg _0.5
X-ray diffraction pattern of O ₄ .

FIG. 2b is an embodiment of the present invention LiMn _1.5 Mg _0.5
X-ray diffraction pattern of O ₄ .

FIG. 3a is an embodiment of the present invention LiMn _1.5 Zn _0.5.
X-ray diffraction pattern of O ₄ .

FIG. 3b is an embodiment of the present invention LiMn _1.5 Zn _0.5.
X-ray diffraction pattern of O ₄ .

FIG. 4a is an embodiment of the present invention LiMn _1.5 Ni _0.5
X-ray diffraction pattern of O ₄ .

FIG. 4b is an embodiment of the present invention LiMn _1.5 Ni _0.5.
X-ray diffraction pattern of O ₄ .

FIG. 5a: LiMn _1.95 Fe, an embodiment of the present invention.
X-ray diffraction pattern of _0.05 O ₄ .

FIG. 5b is an example of the present invention, LiMn _1.9 Fe _0.1
X-ray diffraction pattern of O ₄ .

FIG. 5c is an embodiment of the present invention LiMn _1.8 Fe _0.2
X-ray diffraction pattern of O ₄ .

FIG. 5d is an embodiment of the present invention LiMn _1.7 Fe _0.3
X-ray diffraction pattern of O ₄ .

FIG. 5e is an embodiment of the present invention LiMn _1.5 Fe _0.5
X-ray diffraction pattern of O ₄ .

FIG. 5f: LiMn _1.3 Fe _0.7 which is an example of the present invention.
X-ray diffraction pattern of O ₄ .

FIG. 6a: 0.5 of LiMn ₂ O ₄ which is a comparative example of the present invention.
FIG. 6 is a characteristic diagram showing charge / discharge characteristics at mA / cm ² discharge current.

FIG. 6b is an embodiment of the present invention LiMn _1.9 Fe _0.1
Characteristic diagram showing charge-discharge characteristics at 0.5 mA / cm ² discharge current O _4.

FIG. 6c is an embodiment of the present invention LiMn _1.8 Fe _0.2
The characteristic view which shows the charging / discharging characteristic at the time of 0.5 mA / cm ² discharge current of O ₄ .

FIG. 6d is an example of the present invention LiMn _1.7 Fe _0.3
Characteristic diagram showing charge-discharge characteristics at 0.5 mA / cm ² discharge current O _4.

FIG. 7a: 3 mA of LiMn ₂ O ₄ which is a comparative example of the present invention
6 is a characteristic diagram showing charge / discharge characteristics at a discharge current of / cm ² ;

FIG. 7b is an example of the present invention, LiMn _1.9 Fe _0.1
FIG. 6 is a characteristic diagram showing charge / discharge characteristics of O ₄ at a discharge current of 3 mA / cm 2;

FIG. 7c is an example of the present invention, LiMn _1.8 Fe _0.2
FIG. 3 is a characteristic diagram showing charge / discharge characteristics of O ₄ at 3 mA / cm ² discharge current.

FIG. 7d is an embodiment of the present invention LiMn _1.7 Fe _0.3
FIG. 3 is a characteristic diagram showing charge / discharge characteristics of O ₄ at 3 mA / cm ² discharge current.

FIG. 8a: 3 mA of LiMn ₂ O ₄ which is a comparative example of the present invention
6 is a characteristic diagram showing charge / discharge characteristics at a discharge current of / cm ² ;

FIG. 8b is an embodiment of the present invention LiMn _1.9 Ni _0.1
FIG. 6 is a characteristic diagram showing discharge characteristics of O ₄ at a discharge current of 3 mA / cm ² ;

FIG. 8c is an example of the present invention, LiMn _1.9 Co _0.1.
FIG. 6 is a characteristic diagram showing discharge characteristics of O ₄ at a discharge current of 3 mA / cm ² ;

FIG. 8d is an embodiment of the present invention LiMn _1.9 Fe _0.1
FIG. 6 is a characteristic diagram showing discharge characteristics of O ₄ at a discharge current of 3 mA / cm ² ;

[Explanation of symbols]

 1 Stainless steel sealing plate 2 Polypropylene gasket 3 Stainless steel positive electrode case 4 Lithium negative electrode 5 Polypropylene separator 6 Positive electrode mixture pellet

[Table 2]

[Procedure amendment]

[Submission date] August 23, 1991

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Detailed explanation of the invention

[Correction method] Change

[Correction content]

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a non-aqueous electrolyte battery,
More specifically, the present invention relates to a chargeable / dischargeable non-aqueous electrolyte secondary battery, and particularly to the improvement of the positive electrode active material, with the aim of increasing the charge / discharge capacity of the battery.

[0002]

2. Description of the Related Art Non-aqueous electrolyte batteries using an alkali metal such as lithium or an alloy or compound thereof as a negative electrode active material have a large capacity due to the insertion or intercalation reaction of negative electrode metal ions into the positive electrode active material. It has both discharge capacity and reversibility of charge. Conventionally, as a secondary battery using lithium as a negative electrode active material, a battery using a layered or tunnel oxide such as vanadium pentoxide or manganese dioxide that can be an intercalation host for lithium has been proposed. However, the voltage was low and the charge / discharge energy density was not sufficient. Recently, cubic LiMn with spinel structure
It has been reported that it can be discharged at 4 V when it is initially charged to about 4.5 V with ₂ O ₄ and then discharged (Journal of Electrochemical Society, 1990, Vol. 137, No. 3).
769).

However, in this 4V region, when the composition region of Li / Mn ₂ O ₄ > 1.1 or more is reached due to the progress of discharge, a structural phase transition from cubic to tetragonal occurs, and the discharge voltage corresponding to this occurs. Suddenly drops to 2.8V. Further, this cubic crystal had poor discharge characteristics in the 4V region, and its cycle capacity was halved in less than 50 cycles.

[0004]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a non-aqueous electrolyte battery which is small in size and has battery characteristics which are excellent in charge and discharge characteristics by improving the above problems.

[0005]

In order to achieve such an object, in the non-aqueous electrolyte battery of the present invention, the composition formula: LiMn _{2- x}
A material represented by M ′ _x O 4 (0 <x ≦ 0.7) is included as a positive electrode active material, an alkali metal or a compound thereof is used as a negative electrode active material, and the positive electrode active material and the negative electrode active material are chemically reacted. It is characterized in that the electrolyte material is a material which is stable and is capable of moving alkali metal ions to cause an electrochemical reaction with the positive electrode active material or the negative electrode active material.

Generally, spinel has a composition of AB ₂ O ₄ . Where A is a metal element surrounded by an oxygen tetrahedron, B
Is a metal element surrounded by octahedra of oxygen.

[0007] Positive electrode active material of the present _{invention, LiMn 2-x M 'x} O
₄ is a manganese spinel oxide, Mn located at an octahedral site in LiMn ₂ O ₄ , which is another element ion M'of low oxidation number.
Is a ternary oxide substituted and added, more preferably L
_{iMn 2-x M 'x O} 4 is used to form the dopant M' is a trivalent metal element ions from monovalent. Result of replacement additive by other element ions of Mn ^3+, reduces the abundance ratio of Mn ³⁺ ions with Jahn-Teller instability, stabilized with a wider composition range cubic spinel structure, the charge-discharge characteristics were improved by this it is conceivable that.

[0008] Positive electrode active material in the present invention as described above, 'is shown by _x O _4, such a low oxidation number of the element M' LiMn _2-x M as, for example Al, Sc, F
e, Ni, Co, Mg, V, Y, Zn, Ti, Sb, C
One or more of u and the like can be mentioned.

Further, x is preferably in the range of 0 <x ≦ 0.7. This is because if the doping amount x exceeds 0.7, many other phases may be formed. Particularly preferably 0 <
x ≦ 0.5, and more preferably 0 <x ≦ 0.2.

[0010] This forms a positive electrode using the positive electrode active material, nickel _{LiMn 2-x M 'x O} 4 compound powder and a mixture of polytetrafluoroethylene Gotoki binder powder,
Press-mold on a support such as stainless steel. Alternatively,
In order to impart conductivity to the mixed substance powder, a conductive powder such as pyrolytic graphite or acetylene black is mixed, and a binder powder such as polytetrafluoroethylene is further added thereto, if necessary, and the mixture is mixed. Is placed in a metal container, or the mixture is pressure-molded on a support such as nickel or stainless steel.

Lithium, which is the negative electrode active material, is formed into a sheet shape like that of a general lithium battery, or the sheet is pressure-bonded to a conductor network of nickel, stainless steel or the like to form a negative electrode. As the negative electrode active material, in addition to lithium, conventionally known materials such as lithium alloys and lithium compounds, magnesium, calcium, and sodium can be used.

As the electrolyte, for example, an organic solvent such as dimethoxyethane, 2-methyltetrahydrofuran, ethylene carbonate, methyl formate, dimethylsulfoxide, propylene carbonate, acetonitrile, butyrolactone, dimethylformamide and LiA can be used.
sF ₆ , LiBF ₄ , LiPF ₆ , LiAlCl ₄ , LiC
A non-aqueous electrolyte solution in which a Lewis acid such as 10 ₄ is dissolved can be used.

Further, conventionally known materials can be used for other elements such as a separator and a structural material (battery case, etc.), and there is no particular limitation.

[0014]

EXAMPLES The method of the present invention will be described in more detail with reference to the following examples, which should not be construed as limiting the invention thereto. In the examples, the production and measurement of batteries were performed in a dry box under an argon atmosphere.

[0015]

EXAMPLE 1 FIG. 1 is a cross-sectional view of a coin-type battery which is one specific example of the battery according to the present invention, in which 1 is a stainless steel sealing plate, 2 is a polypropylene gasket, 3 is a positive electrode case made of stainless steel, 4 Is a lithium negative electrode, 5 is a polypropylene microporous separator, and 6 is a positive electrode material mixture pellet.

The positive electrode active material was prepared by substituting various metal elements shown in Table 1 as dopants for substitution and addition of Mn with respect to unsubstituted LiMn ₂ O ₄ , fixing the dope amount to x = 0.5 and weighing and mixing. In addition, a ternary compound oxide crystal powder obtained by heating at 650 ° C. for about 6 hours in the air and further firing at 850 ° C. for 24 hours was used.

Among the obtained powder samples, as an example, Li
Mn _1.5 Mg _0.5 O ₄ , LiMn _1.5 Zn _0.5 O ₄ , LiMn
The X-ray diffraction patterns of _1.5 Ni _0.5 O ₄ are shown in FIGS. 2a-4b. All the peaks are in good agreement with each profile of ASTM, and the main peak of LiMn ₂ O ₄ remains, so that at least up to this composition, there is no substitution of LiM.
It can be seen that Mn is replaced with the added metal element in a solid solution state while maintaining the n ₂ O ₄ spinel structure.

The obtained LiMn _1.5 M _'0.5 O ₄ crystals a conductive agent (acetylene black powder) with a binder (polytetrafluoroethylene), 70: 25: on the mixed in a weight ratio of 5, and roll forming The positive electrode material mixture pellet 6 (thickness 0.5 mm, diameter 17 mm, 200 mg / ce 11) was used. First, the metallic lithium negative electrode 4 placed under pressure on the sealing plate 1 is inserted into the concave portion of the gasket 2, and the separator 5 and the positive electrode material mixture pellet 6 are arranged in this order on the metallic lithium negative electrode 4 to form the electrolyte solution. As an appropriate amount of 1N solution of LiClO ₄ dissolved in an equal volume mixed solvent of propylene carbonate (PC) and 2-dimethoxyethane (DME), respectively, is injected and impregnated, the positive electrode case 3 is covered and caulked. A coin-type battery having a thickness of 2 mm and a diameter of 23 mm was produced.

0.5 mA of the battery thus produced
Table 1 shows the cell discharge capacities up to each cutoff voltage at a discharge current density of / cm ² .

[0020]

[Table 1]

[0021] LiMn is in LiMn _1.5 M _'0.5 O _4
1.5 Al _0.5 O ₄ , LiMn _1.5 Sc _0.5 O ₄ , LiMn _1.5
Fe _0.5 O ₄ , LiMn _1.5 Ni _0.5 O ₄ , LiMn _1.5 Co
_0.5 O ₄ is a system having a relatively large discharge capacity in the high voltage portion of 4V.

[0022]

Example 2 As for the positive electrode active material, x = 0.05 to 0.7 with respect to unsubstituted LiMn ₂ O ₄ with Fe ³⁺ as a dopant.
The ternary compound oxide crystal powder obtained by weighing and mixing the dope amount as shown in the following formula, heating at 650 ° C. for about 6 hours in the air, and then firing at 850 ° C. for 24 hours was used.

Li ₂ CO ₃ + (2-x) Mn ₂ O ₃ + xFe
_{2 O 3 + 0.5O 2 → 2LiMn} 2-x Fe x O 4 + CO 2 ↑

Among the obtained powder samples, as an example, Li
Mn _1.95 Fe _0.05 O ₄ , LiMn _1.9 Fe _0.1 O ₄ , LiM
n _1.8 Fe _0.2 O ₄ , LiMn _1.7 Fe _0.3 O ₄ , LiMn
_1.6 Fe _0.4 O ₄ , LiMn _1.5 Fe _0.5 O ₄ , LiMn _1.3
The X-ray diffraction patterns of Fe _0.7 O ₄ are shown in Figures 5a to 5f. Since the main peak of LiMn ₂ O ₄ remains in all the peaks, Mn forms a solid solution with the additive metal element while maintaining the unsubstituted LiMn ₂ O ₄ spinel structure at least up to the composition of x = 0.7. You can see that it has been replaced by the state.

The positive electrode active material, except using LiMn _2-x Fe _x O ₄ was synthesized as described above to prepare a lithium battery in the same manner as in Example 1.

0.5 mA of the battery thus produced
/ Cm ² and ^3. at discharge current densities of 3 mA / cm ² .
Table 2 shows the cell discharge capacities up to 5 V final voltage, and FIG. 6a to FIG. 6d and FIG.
~ Shown in Figure 7d. Note that x is 0, 0.1, 0.2, 0.
It was set to 3. The first sample in Figures 6a and 7a and Table 2 is x = 0, ie the comparative example.

[0027]

[Table 2]

[0028] Figures 6a 6d, Figure 7d and Figures 7a, in Table 2 Results _{LiMn 2-x Fe x O 4} , doped amount 0 <particularly discharge capacity ones x ≦ 0.2, It can be seen that it is suitable in terms of cycle life. Further, the superiority to unsubstituted LiMn ₂ O ₄ spinel is 3 mA / cm 2.
It is especially noticeable during the high current discharge of ² .

[0029]

[Example 3] The positive electrode active material was prepared by fixing the dope amount to unsubstituted LiMn ₂ O ₄ at x = 0.01, weighing and mixing various low oxidation number metal elements as dopants, and then mixing at 650 ° C.
After heating in the air for about 6 hours and further firing at 850 ° C. for 24 hours, a ternary compound oxide crystal powder was used.

The positive electrode active material, except using _{LiMn 2-x M 'x O} 4 was synthesized as described above, to produce a lithium battery in the same manner as in Example 1.

As an example, FIGS. 8a to 8d show discharge curves up to a final voltage of 3.5 V at a discharge current density of 3 mA / cm ^{2 of the} battery thus manufactured. FIG. 8a is a discharge curve of LiMn ₂ O ₄ of a comparative example, and FIGS. 8b to 8d are discharge curves of Ni, Co, and Fe at x = 0.1.

Similar to LiMn _1.9 Fe _0.1 O ₄ , Co, N
When i, Al, Mg, and Sc were added, the superiority was remarkable over the unsubstituted LiMn ₂ O ₄ spinel in terms of discharge capacity and overvoltage. In any case, it is considered that the addition of these low oxidation number ions reduced the abundance ratio of Mn ^{3+ having} Yanteller instability, which led to the improvement of the characteristics, and the addition of other low oxidation number ions had the same effect. Can be expected. The doping amount is 0 <x ≦ 0.
5, especially, the case of 0 <x ≦ 0.2 is particularly preferable.

[0033]

As described above, according to the present invention,
It is possible to construct a small-sized and high-energy-density lithium battery having a large reversible capacity, and the battery of the present invention has an advantage that it can be used in various fields such as a coin battery.

 ─────────────────────────────────────────────────── --- Continuation of the front page (72) Inventor Hajime Arai 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Inside Nippon Telegraph and Telephone Corporation (72) Inventor Masahiro Ichimura 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo No. Japan Nippon Telegraph and Telephone Corp. (72) Inventor Junichi Yamaki 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corp.

Claims (1)

Claims: 1. A composition formula, LiMn _2-x M, in which Mn ions of LiMn ₂ O ₄ are substituted and added with elemental (M ') ions other than monovalent to hexavalent Mn to form a solid solution. ' _x O ₄ as the spinel-type mixed oxide as a positive electrode active material, an alkali metal or a compound thereof as a negative electrode active material, and chemically stable with respect to the positive electrode active material and the negative electrode active material, and A non-aqueous electrolyte battery, characterized in that an electrolyte substance is used as a substance capable of moving an alkali metal ion to cause an electrochemical reaction with the positive electrode active material or the negative electrode active material.