JP2002050359A - Manufacturing method of lithium secondary battery positive electrode material and lithium secondary battery positive electrode material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the positive electrode material so that lowering of the battery characteristics is not easily caused when lithium transition metal oxide is used. SOLUTION: After the heating treatment and/or the decompression treatment have been made to the lithium transition metal oxide, a compound (A), which is capable of adsorption to the adsorption site of the surface of the lithium transition metal oxide after such treatment process, is added (provided that the compound (A) is a compound which can give a property to the battery).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a positive electrode material for a lithium secondary battery and a positive electrode material for a lithium secondary battery, and further relates to a positive electrode and a lithium secondary battery using the same.

[0002]

2. Description of the Related Art Recent positive electrode active materials for lithium secondary batteries
Remarkable improvement, expensive LiCoO _TwoL instead of
iNiO_Two, LiMn_TwoO_FourSuch as relatively cheap and resources
Oxides with transition metal elements abundant
Entering. Lithium nickel oxide has a charge / discharge capacity
And high temperature cycle characteristics
Have. However, on the other hand, the aging of the oxide itself during storage
It has problems such as large deterioration. Lithium manganese
Oxide is particularly rich in manganese as a constituent element.
Benefits of being rich and high in overcharge
have. However, on the other hand, in high temperature environments,
Important characteristics for practical use such as car characteristics and storage characteristics
Problem is that it is reduced to a level that causes trouble
I have Problems with each active material as described above
Cathode active material for lithium secondary batteries is practical to overcome
This is an issue for quality.

[0003] For example, in the case of lithium nickel oxide, measures have been taken to prevent the deterioration over time by controlling the surrounding atmosphere (humidity and carbon dioxide gas) during storage.
However, it is extremely difficult industrially to constantly control the environment during storage and use at all times, and after all, the fact is that the battery characteristics tend to vary due to the causes described above.

With respect to lithium manganese oxide, studies for the purpose of improving characteristics in a high temperature environment have been vigorously conducted.
It has been reported. For example, J. Electrochem.soc., Vol.14
5, No. 8 (1998) 2726-2732 discloses a lithium manganese oxide in which a part of Mn is replaced by another element such as Ga or Cr, and Electrochemical Society Proceedings Vo
In lume97-18.494, there is disclosed one in which part of Mn is substituted with Co or part of oxygen is substituted with F to improve the stability of the crystal structure. However, these are the results when metallic lithium is used as the negative electrode, and the fact is that further improvement in performance is required in combination with a practical negative electrode material such as a carbon material.

Further, it has been pointed out that manganese-based lithium secondary batteries easily dissolve manganese in a high-temperature environment as a problem of high-temperature storage deterioration and high-temperature cycle deterioration. M in the cathode material
Investigations such as adding a substance having an n-elution-suppressing effect are also being made. However, in recent years, the level of demand for higher performance of lithium secondary batteries is high, and further improvement in cycle characteristics under a high temperature environment is required.

Japanese Patent No. 3024636 states that high-temperature characteristics are improved by using a combination of a spinel type lithium manganese composite oxide and a lithium nickel composite oxide having a specific specific surface area or a specific particle size. However, the use of lithium nickel oxide, which is mainly composed of nickel, which is still relatively expensive and is not rich in resources, must be used. This leads to problems of complication of the process and an increase in cost, which is not always a preferable improvement.

[0007] Lithium transition metal oxides are generally
There is also a problem that the battery performance varies depending on the storage environment. Furthermore, various compounds are blended in the positive electrode material and the electrolytic solution in order to improve the characteristics of the battery. However, in the conventional method, only the effect for the purpose of blending the compound is exhibited, and the battery characteristics are deteriorated. No improvement could be expected that would be difficult.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a method for producing a positive electrode material for a lithium secondary battery, which is improved so that when a lithium transition metal oxide is used as a positive electrode active material, deterioration in battery characteristics hardly occurs. An object of the present invention is to provide the positive electrode material, a positive electrode for a lithium secondary battery, and a lithium secondary battery.

[0009]

The surface atoms of the crystal have a high degree of reactivity because the bonds are unsaturated, and are liable to adsorb impurities. Under normal conditions, the metal oxide surface retains various adsorbates, including surface hydroxyl groups, and
It is generally considered that in the atmosphere, water is adsorbed to hold physically adsorbed water (surface hydroxyl groups and water molecules are adsorbed via hydrogen bonds). More strictly, the surface state of the metal oxide is complicated, and it is considered that the surface state varies depending on the type, composition, crystal structure, and the like of the transition metal element. This is also true for lithium transition metal oxides. In view of the above, when the type of active material is different, for example, it was thought that one of the reasons for the difference in characteristics between lithium nickel oxide and lithium manganese oxide may be a difference in each surface state. . Further, it is considered that variations in battery performance due to storage environments also cause differences in surface conditions due to differences in storage environments.

When lithium nickel oxide is immersed in pure water, the pH of the immersion water becomes strongly basic. Further, if the lithium nickel oxide is left in the atmosphere, it absorbs moisture and carbon dioxide gas over time and deteriorates. From these results, in the case of lithium nickel oxide, water existing in the gas phase is dissociated and adsorbed to generate surface hydroxyl groups, but only hydrogen ions are adsorbed and Li ions are released and dissociated instead. It is presumed that the electric neutrality is maintained due to the remaining hydroxide ions. Since the lithium hydroxide generated on the surface reacts with carbon dioxide gas in the atmosphere, the concentration of carbonic acid increases with time, and the surface is considered to be mainly covered with lithium carbonate.

A lithium secondary battery using lithium nickel oxide whose surface is covered with lithium carbonate as a positive electrode active material causes an increase in resistance, resulting in a decrease in output characteristics and low-temperature characteristics and a decrease in charge / discharge capacity. Various effects. On the other hand, even if the spinel-type lithium manganese oxide is immersed in pure water, the pH of the immersion water does not show the strong basicity unlike lithium nickel oxide. Even when the oxide is left in the air, almost no absorption of carbon dioxide over time is observed. From these results, in the case of lithium manganese oxide, water existing in the gas phase is dissociated and adsorbed to generate surface hydroxyl groups, but it is necessary to adsorb both dissociated hydrogen ions and hydroxide ions and release Li ions. It is presumed that there is no. Therefore, it is presumed that the lithium manganese oxide is first covered with the surface hydroxyl groups, and is stably present in a state where the water molecules are physically adsorbed via hydrogen bonds.

A lithium secondary battery using lithium manganese oxide holding physically adsorbed water as a positive electrode active material,
The adsorbed water has a detrimental effect on the non-aqueous battery, such as causing decomposition of the electrolytic solution. In particular, under a high temperature environment, the active material surface becomes active, and it is considered that a catalytic reaction causes a deterioration reaction inside the battery,
It was thought that this catalytic action was promoted by the presence of adsorbed water.

The present inventor has proposed a treatment step for adjusting the surface state of the lithium transition metal oxide, and the step of adjusting the surface of the lithium transition metal oxide so as not to return to the state in which the oxide surface adjusted by the treatment is again adsorbed by the undesirable adsorbate. It has been found that the use of a positive electrode material that has been subjected to a mixing step for adsorbing an appropriate compound on the adsorption site improves battery characteristics, and the present invention has been completed. The above-mentioned suitable compound may be any compound that does not lower the battery characteristics, but in the present invention, if various compounds are used to improve certain characteristics of the battery, the compound may be used for the purpose of compounding the compound. In addition to exhibiting the effect, the effect of "improvement in which the deterioration of the battery characteristics hardly occurs" aimed at by the present invention can be exhibited.

That is, the gist of the present invention is the following (1) to (3)
8). (1) Heat treatment and / or
Alternatively, a method for producing a positive electrode material for a lithium secondary battery, comprising mixing a compound (A) that can be adsorbed to an adsorption site on the surface of a lithium transition metal oxide after the treatment after performing a reduced pressure treatment step. (However, the compound (A) is a compound that imparts characteristics to the battery.)
The method for producing a positive electrode material for a lithium secondary battery according to the above (1), wherein the state at 00 ° C. and below the atmospheric pressure is maintained for 0.5 to 24 hours.

(3) The heat treatment and / or the decompression treatment step is carried out at room temperature to 200 ° C. and 1 torr or less for 0.5 to 2 hours.
(1) characterized in that it is held for 4 hours.
3. The method for producing a positive electrode material for a lithium secondary battery according to 1.). (4) The lithium transition metal oxide is maintained at a temperature of 100 to 200 ° C. and below atmospheric pressure for 0.5 to 24 hours, and then mixed with a compound (A) capable of adsorbing to a hydroxyl group. Method for producing positive electrode material for secondary battery. (However, the compound (A) is a compound that gives characteristics to the battery.) (5) After the lithium transition metal oxide is kept at room temperature to 200 ° C. and 1 torr or less for 0.5 to 24 hours, it is adsorbed to a hydroxyl group. A method for producing a positive electrode material for a lithium secondary battery, comprising mixing a possible compound (A). (However, compounds
(A) is a compound that gives characteristics to the battery. (6) The lithium secondary battery according to any one of (1) to (5), wherein after the heat treatment and / or the pressure reduction step, the gas generated by the heat treatment and / or the pressure reduction is exhausted. Method for producing positive electrode material for secondary battery.

(7) After the heat treatment and / or the reduced pressure treatment, the work steps until the mixing of the compound (A) is completed are performed in a dry atmosphere having a dew point of -30 ° C. or less. The method for producing a positive electrode material for a lithium secondary battery according to any one of (1) to (6). (8) The positive electrode material for a lithium secondary battery according to any one of the above (1) to (7), wherein the lithium transition metal oxide is a lithium manganese oxide having a spinel structure or a layered structure. Production method.

(9) The lithium transition metal oxide is a lithium manganese oxide having a cubic spinel structure and a part of Mn sites substituted with other elements. The method for producing a positive electrode material for a lithium secondary battery according to any one of the above. (10) The surface hydroxyl groups are exposed by removing the physically adsorbed water on the surface of the lithium manganese oxide, and then the compound (A) capable of adsorbing the surface hydroxyl groups as an adsorption site is mixed to convert the compound (A) into the surface hydroxyl groups. A method for producing a positive electrode material for a lithium secondary battery, characterized by adsorbing. (However, the compound (A) is a compound that gives characteristics to the battery.) (11) Removal of the physically adsorbed water on the surface of the lithium manganese oxide is performed at a temperature of 100 to 200 ° C. and below atmospheric pressure by 0.5.
(10) The method for producing a positive electrode material for a lithium secondary battery according to the above (10), wherein the method is performed by holding for about 24 hours.

(12) The removal of physically adsorbed water on the surface of the lithium manganese oxide is carried out by maintaining a state of room temperature to 200 ° C. and 1 torr or less for 0.5 to 24 hours. 3. The method for producing a positive electrode material for a lithium secondary battery according to 1.). (13) The lithium secondary battery according to any one of (1) to (12), wherein the compound (A) is a compound having a molecule having an unshared electron pair and / or a π electron. Manufacturing method of positive electrode material.

(14) The compound (A) is a compound having at least one element selected from nitrogen, phosphorus, arsenic, antimony, oxygen, sulfur, selenium, tellurium, fluorine, chlorine, bromine and iodine. The method for producing a positive electrode material for a lithium secondary battery according to any one of the above (1) to (13), wherein: (15) When the compound (A) is nitrogen, oxygen,
The positive electrode material for a lithium secondary battery according to any one of the above (1) to (14), which is a heterocyclic compound containing at least one or more atoms selected from sulfur as a ring-constituting element. Production method.

(16) The compound according to any one of the above (1) to (15), wherein the compounding amount of the compound (A) is 0.1 to 10 mol% based on the lithium transition metal oxide. Method for producing a positive electrode material for a lithium secondary battery. (17) A compound capable of being subjected to a heat treatment and / or a decompression treatment step on a lithium transition metal oxide and then adsorbed on an adsorption site on the surface of the lithium transition metal oxide after the treatment
A positive electrode material for a lithium secondary battery mixed with (A). (However, the compound (A) is a compound that imparts characteristics to the battery.)
The positive electrode material for a lithium secondary battery according to the above (17), wherein the positive electrode material is maintained at a temperature of 200 ° C. and the atmospheric pressure or lower for 0.5 to 24 hours.

(19) The heating and / or depressurizing step is performed at room temperature to 200 ° C. and 1 torr or less for 0.5 to 2 hours.
(1) characterized in that the above (1) is maintained for 4 hours.
The positive electrode material for a lithium secondary battery according to 7). (20) Lithium transition metal oxide at 100 to 200 ° C
And after holding for 0.5 to 24 hours under the atmospheric pressure,
A positive electrode material for a lithium secondary battery in which a compound (A) that can be adsorbed on a hydroxyl group is mixed. (However, the compound (A) is a compound that gives characteristics to the battery.) (21) After the lithium transition metal oxide is kept at room temperature to 200 ° C. and 1 torr or less for 0.5 to 24 hours, it is adsorbed to a hydroxyl group. A positive electrode material for a lithium secondary battery obtained by adding and mixing the possible compound (A).

(22) The method according to any one of the above (17) to (21), wherein after the heat treatment and / or the pressure reduction step, the gas generated by the heat treatment and / or the pressure reduction is exhausted. Positive electrode material for lithium secondary batteries. (23) After the heat treatment and / or reduced pressure treatment step, the compound
The working process until the mixing of (A) is completed, the dew point is -30 ° C
The positive electrode material for a lithium secondary battery according to any one of the above (17) to (22), which is performed in the following dry atmosphere.

(24) The surface hydroxyl groups are exposed by removing the physically adsorbed water on the surface of the lithium manganese oxide, and then the compound (A) capable of adsorbing the surface hydroxyl groups as an adsorption site is mixed, whereby the compound (A) is added to the surface hydroxyl groups. A) A positive electrode material for lithium secondary batteries that has adsorbed thereon. (However, the compound (A) is a compound that gives characteristics to the battery.) (25) Removal of physically adsorbed water on the surface of the lithium manganese oxide is performed at a temperature of 100 to 200 ° C. and at atmospheric pressure or lower by 0.5.
The positive electrode material for a lithium secondary battery according to the above (24), wherein the positive electrode material is held by holding for up to 24 hours.

(26) The removal of physically adsorbed water on the surface of the lithium manganese oxide is carried out by maintaining a state of room temperature to 200 ° C. and 1 torr or less for 0.5 to 24 hours. 4. The positive electrode material for a lithium secondary battery according to 4. (27) A positive electrode material for a lithium secondary battery in which the compound (A) is adsorbed on the surface of a lithium manganese oxide via a surface hydroxyl group of the lithium manganese oxide. (However, the compound (A) is a compound that imparts characteristics to the battery.) (28) The compound (A) is a compound having a molecule having an unshared electron pair and / or a π electron. 17) The positive electrode material for a lithium secondary battery according to any one of (27) to (27).

(29) The compound (A) is a compound containing at least one element selected from nitrogen, phosphorus, arsenic, antimony, oxygen, sulfur, selenium, tellurium, fluorine, chlorine, bromine and iodine. The positive electrode material for a lithium secondary battery according to any one of the above (17) to (28), wherein: (30) When the compound (A) is nitrogen, oxygen,
The positive electrode material for a lithium secondary battery according to any one of the above (17) to (29), which is a heterocyclic compound containing at least one or more atoms selected from sulfur as a ring constituent element.

(31) The compound according to any one of the above (17) to (30), wherein the compounding amount of the compound (A) is 0.1 to 20 mol% based on the lithium transition metal oxide. Positive electrode material for lithium secondary batteries. (32) The positive electrode material for a lithium secondary battery according to any one of the above (17) to (31), wherein the lithium transition metal oxide is a lithium manganese oxide having a spinel structure or a layered structure.

(33) The lithium transition metal oxide according to the above (17) to (32), wherein the lithium transition metal oxide is a lithium manganese oxide having a cubic spinel structure and a part of Mn sites substituted by another element. The positive electrode material for a lithium secondary battery according to any one of the above. (34) Other elements are Al, Ti, V, Cr, Fe, L
The positive electrode material for a lithium secondary battery according to (33), wherein the positive electrode material is selected from the group consisting of i, Co, Ni, Cu, Zn, Mg, Ga, and Zr.

(35) BET of lithium manganese oxide
The positive electrode material for a lithium secondary battery according to any one of the above (17) to (34), having a specific surface area of 0.3 to 1.5 m ² / g. (36) A positive electrode for a lithium secondary battery, comprising the positive electrode material for a lithium secondary battery according to any one of the above (17) to (35).

(27) A positive electrode comprising the positive electrode material for a lithium secondary battery according to any of (17) to (35),
A lithium secondary battery comprising a negative electrode and an electrolyte. (38) The lithium secondary battery according to the above (37), wherein the active material of the negative electrode is a carbon material.

[0030]

DETAILED DESCRIPTION OF THE INVENTION In the present invention, after a lithium transition metal oxide is subjected to a heat treatment and / or a pressure reduction step, it can be adsorbed to an adsorption site on the surface of the lithium transition metal oxide after the treatment. It is essential that the compound (A) is mixed. In the present invention, “heating treatment and / or decompression treatment” is a treatment step for adjusting the surface state of the lithium transition metal oxide. Under normal conditions, the metal oxide surface retains various adsorbates including surface hydroxyl groups, and furthermore, at room temperature and in the air, usually adsorbs water to form physically adsorbed water (surface hydroxyl groups and water molecules). Are adsorbed via hydrogen bonds). This is subjected to heat treatment and / or reduced pressure treatment to remove adsorbed substances such as adsorbed water and the like, and adsorption sites appear on the surface of the lithium transition metal oxide. The surface state of the oxide can be changed by changing the heating temperature, the pressure reduction condition, the treatment time, and the like.
As the surface state, the surface adsorbed substances such as the physically adsorbed water are removed and the surface hydroxyl groups appear, and the surface hydroxyl groups are further desorbed (water molecules dissociate into hydrogen ions and hydroxide ions and adsorb on the metal oxide surface (Reverse process of generation of surface hydroxyl groups), and a state in which coordinatively unsaturated metal ions and oxygen ions appear. Surface hydroxyl groups, coordinatively unsaturated metal ions, oxygen ions and the like may be present on the surface. Each parameter such as temperature, decompression condition, and time can be set independently. Conditions for obtaining a desired surface state may be arbitrarily determined according to the type of each lithium transition metal oxide. For example, in general, when it is desired to desorb the physically adsorbed water on the metal oxide surface, it is sufficient to perform evacuation at around room temperature, and to completely desorb the surface hydroxyl groups,
In many cases, high-temperature evacuation at 800 to 1000 ° C. is required. Other adsorbed molecules such as CO ₂ adsorbed on the surface can also be desorbed by appropriately setting the processing conditions. Generally, the processing time can be shortened as the processing temperature and / or the degree of evacuation is higher, and conversely, the processing time needs to be longer as the processing temperature and / or the degree of evacuation are lower. In particular,
As the heat treatment and / or pressure reduction treatment in the present invention,
(A) A state at 100 to 200 ° C. and below atmospheric pressure is 0.5
Heat treatment and / or decompression treatment in which (B) a heat treatment and / or a decompression treatment step includes a treatment in which a state of room temperature to 200 ° C. and 1 torr or less is kept for 0.5 to 24 hours. Even if the desired surface condition is achieved, if the temperature is returned to normal temperature and normal pressure while the gas generated by the heat treatment and / or the decompression treatment remains, the desorbed substances from the surface may be re-adsorbed on the surface. So, for example,
After the heat treatment and / or the reduced pressure treatment step, the heat treatment and / or
Alternatively, it is preferable that gas generated by the decompression treatment is exhausted and removed.

In the working process after the above-mentioned treatment process and before the mixing of the compound (A) is completed, the adjusted surface condition is contaminated by re-adsorption of water molecules and CO _{2 in the} outside world, and the compound (A) is contaminated. It is important to avoid the inability to adsorb as much as possible. Working environment is dry atmosphere, low CO ₂
A partial pressure atmosphere is preferred. The environment of the dry atmosphere is usually a dew point of 0 ° C. or lower, preferably −30 ° C. or lower, more preferably −40 ° C. or lower. The low CO ₂ partial pressure environment is usually 3 × 10 ⁻⁴ atm or less, preferably 10 ⁻⁵ atm or less, more preferably 10 ⁻⁶ atm or less.

In the present invention, the term "adsorption site on the surface of the lithium transition metal oxide" means a site capable of adsorbing a certain adsorbed molecule such as a coordinatively unsaturated metal ion or oxygen ion or a surface hydroxyl group. The compound (A) in the present invention is a compound that imparts characteristics to a battery, and may be any compound that can be adsorbed on an adsorption site on the surface of a lithium transition metal oxide,
Specifically, for example, it is only necessary to be able to adsorb to a hydroxyl group, a coordinatively unsaturated metal ion, an oxygen ion and the like on the surface of the lithium transition metal oxide. Therefore, a compound having an adsorption ability for a hydroxyl group, a coordinatively unsaturated metal ion, an oxygen ion and the like may be selected.

In the present invention, the compound that imparts characteristics to the battery includes, for example, characteristics that improve the output characteristics, high-temperature characteristics, low-temperature characteristics, cycle characteristics, and storage characteristics of the battery, characteristics that suppress the surface resistance of the electrode, and gas generation. And the characteristic of suppressing deterioration of the battery constituent material. That is,
What is necessary is just to select arbitrarily from the compound which can be mix | blended in order to improve the characteristic of a battery. If these compounds are only added to the lithium transition metal oxide that has not been subjected to the heat treatment and / or the reduced pressure treatment step, only the effects for the purpose of compounding the compounds are exhibited. According to the present invention, in addition to these effects, an improvement (specifically, improvement in high-temperature characteristics, etc.) can be achieved such that further deterioration in battery characteristics does not easily occur.

Various attempts have been made to improve the characteristics of the battery by adding a certain compound to the electrolyte, but the progress of the degradation reaction occurring at the interface between the positive electrode active material and the electrolyte cannot be effectively suppressed. Probability is high. In addition, compound (A)
Some are insoluble or hardly soluble in the electrolytic solution, and it is considered difficult to control the blending amount. Even if possible, there is a danger that it will be restricted by the type of electrolyte. The present invention
By adsorbing the compound (A) on the surface of the positive electrode active material for a lithium secondary battery, it is possible to improve the high-temperature characteristics effectively and independently of the type of the electrolytic solution.

As the compound (A) used in the present invention, a compound having a molecule having an unshared electron pair and / or a π electron is preferable. One reason for this is that the surface hydroxyl groups act as absorption sites for molecules having lone pairs or π electrons. One example is the adsorption of water molecules by hydrogen bonding. More specifically, nitrogen, phosphorus, arsenic, antimony, oxygen, sulfur, selenium, tellurium,
A compound containing at least one or more elements selected from fluorine, chlorine, bromine and iodine, and further contains at least one or more atoms selected from nitrogen, oxygen and sulfur as hetero atoms in the ring constituent elements It is a heterocyclic compound.
Among these compounds, those that can strongly adsorb to the surface are preferable, and those that have high oxidation resistance are preferable in that they are stably present on the surface of the positive electrode active material. Further, a thermodynamically stable compound is preferable, and in the case of an organic compound, an aromatic heterocyclic compound is preferable. In addition, Li accompanying the charge / discharge reaction
It is preferable to use a material having a structure with low steric hindrance or a material having an appropriate electric conductivity from the viewpoint of reducing interference with ion insertion / emission and electron conduction. In addition, a material having high thermal stability is preferable because it can stably exist during heat generation during charging and storage or use in a high-temperature environment. Compound (A)
Is not limited to a specific isomer. Particularly preferred compounds are metal sulfides such as lanthanum sulfide, specific nitrogen-containing heterocyclic compounds such as diazoles having electron-withdrawing substituents (such as nitroimidazole), purine derivatives and succinimide derivatives, saccharin, thianthrene, and trithiane. And a sulfur-containing heterocyclic compound. The above compounds may be used alone or in combination of two or more, or may be used in combination with other additives that are expected to have a synergistic effect.

The amount of the above compound to be used is generally 0.01 to 20 mol%, preferably 0.1 to 10 mol%, more preferably 1 to 5 mol%, based on the lithium transition metal oxide. When the amount of use increases, the discharge capacity may decrease. On the other hand, when the amount decreases, it may be difficult to obtain the effect of improving the characteristics to be improved. In order to mix the compound (A) added in the lithium transition metal oxide, for example, a physical mixing method can be adopted. Physical mixing is a simple mixing method, is not affected by alteration, and is preferable in that the original effect can be sufficiently exhibited. Physical mixing in the present invention,
It means simply mixing together a plurality of substances, and means mixing without heat treatment at such a high temperature that the mixture is chemically changed. It is preferable that the compound is dispersed in a positive electrode active material by stirring a plurality of substances, and it is preferable that the compound is uniformly dispersed. The physical mixing is preferably dry mixing. For physical mixing, a mortar, a ball mill, a jet mill, a Loedige mixer, or the like can be used.
In order to effectively remain in the positive electrode material, a material that is hardly dissolved in the electrolytic solution is preferable. In the present invention, since the adsorption site is present on the surface of the transition metal oxide by heat treatment and / or reduced pressure treatment, and the compound (A) is a compound that can be adsorbed on the adsorption site, the above-described mixing is performed. Thereby, the positive electrode material for a lithium secondary battery in which the compound (A) is adsorbed on the surface of the lithium manganese oxide via the adsorption site of the lithium manganese oxide is obtained.

As an analysis method for determining whether or not the compound (A) is adsorbed on the surface of the lithium transition metal oxide, for example, infrared absorption, Raman spectroscopy, photoacoustic spectroscopy, Mossbauer spectroscopy, polarization analysis But not limited thereto. In the present invention, a lithium transition metal oxide is used as an active material. In the present invention, the active material is a main substance that causes an electromotive reaction of the battery, and means a substance capable of inserting and extracting Li ions. The lithium transition metal oxide used may be any material that can reversibly occlude and release Li as an active material.
Examples of the transition metal used in the lithium transition metal oxide include manganese, nickel, cobalt, iron, chromium, vanadium, titanium, and copper. Preferably, they are manganese, nickel and cobalt, particularly preferably manganese and nickel, most preferably manganese. Of course, a plurality of these can be used.
Preferred lithium transition metals include lithium manganese oxide, lithium nickel oxide, lithium cobalt oxide, lithium iron oxide, lithium chromium oxide, lithium vanadium oxide, lithium titanium oxide, lithium copper oxide, and the like. Can be. As a specific composition formula, for example, a general formula LiMn ₂ O ₄ , LiMnO ₂ , L
_{iNiO 2, LiCoO 2, LiFeO 2} , LiCrO 2,
Li _{1 + x} V ₃ O ₈ , LiV ₂ O ₄ , LiTi ₂ O ₄ , Li ₂ Cu
Compounds represented by O ₂ and LiCuO ₂ can be exemplified. In view of the remarkable effects of the present invention, preferably lithium manganese oxide, more preferably lithium manganese oxide having a spinel structure or a layered structure, particularly cubic spinel represented by general formula LiMn ₂ O ₄ It is a lithium manganese oxide having a structure. Note that the above composition may have a small amount of oxygen deficiency and non-stoichiometric property. Further, a part of the oxygen site may be replaced by sulfur or a halogen element. Further, a part of the site occupied by the transition metal of the lithium transition metal oxide may be replaced with an element other than the transition metal.

As the lithium transition metal oxide used in the present invention, it is preferable that a part of the transition metal site is substituted with another element based on a specific transition metal. As a result, the stability of the crystal structure can be improved, and by combining this with the compound, the high-temperature characteristics can be synergistically improved. This effect is particularly remarkable when a lithium manganese composite oxide is used.

At this time, the other element that substitutes for a part of the transition metal site (hereinafter, referred to as a substitution element) includes A
1, Ti, V, Cr, Mn, Fe, Co, Li, Ni,
Cu, Zn, Mg, Ga, Zr, etc., and preferably, Al, Cr, Fe, Co, Li, Ni, Mg, Ga,
More preferably, it is Al. The transition metal site is 2
It may be replaced by more than one kind of other element.

The substitution ratio by the substitution element is usually at least 2.5 mol% of the base transition metal element, preferably at least 5 mol% of the base transition metal element, and usually at least 30 mol% of the base transition metal element. %, Preferably 20 mol% or less of the base transition metal element. If the substitution ratio is too small, the effect of improving the high-temperature cycle may not be sufficient, and if it is too large, the capacity of the battery may decrease.

The specific surface area of the lithium transition metal oxide used in the present invention is usually at least 0.01 m ^{2 /} g, preferably 0.1 m ^{2 /} g.
3m ² / g or more, more preferably 0.5 m ² / g or more, and usually 10 m ² / g or less, preferably 1.5 m ² /
g or less, and more preferably 1.0 m ² / g or less. If the specific surface area is too small, the rate characteristics and the capacity will be reduced. If the specific surface area is too large, an undesirable reaction with the electrolytic solution or the like will be caused, and the cycle characteristics may be reduced. The measurement of the specific surface area follows the BET method.

The average particle size of the lithium transition metal oxide used in the present invention is usually 0.1 μm or more, preferably 0.2 μm or more.
μm or more, more preferably 0.3 μm or more, most preferably 0.5 μm or more, usually 300 μm or less, preferably 100 μm or less, more preferably 50 μm or less, and most preferably 20 μm or less. If the average particle size is too small, the cycle deterioration of the battery may increase, or a problem may occur in safety. If the average particle size is too large, the internal resistance of the battery may increase, making it difficult to output.

The positive electrode material of the present invention can be used for a positive electrode of a lithium secondary battery. The positive electrode of the present invention has the above positive electrode material and a binder. Preferably, the positive electrode is
It comprises a positive electrode current collector and a positive electrode layer containing a positive electrode material and a binder. Such a positive electrode layer is formed by applying a slurry of a lithium transition metal oxide, a binder (binder), and a conductive agent as necessary, which have been subjected to the above-described processing steps, to a positive electrode current collector, followed by drying. Can be manufactured.

The positive electrode may further contain an active material capable of inserting and extracting lithium ions other than the lithium transition metal oxide that has undergone the above-mentioned treatment steps. The ratio of the active material in the positive electrode is usually 10% by weight or more, preferably 30% by weight.
And more preferably 50% by weight or more, usually 9% by weight.
It is at most 9.9% by weight, preferably at most 99% by weight.
If the amount is too large, the mechanical strength of the electrode tends to be inferior. If the amount is too small, the battery performance such as capacity tends to be inferior.

As the binder used for the positive electrode, for example, polyvinylidene fluoride, polytetrafluoroethylene, fluorinated polyvinylidene fluoride, EPDM
(Ethylene-propylene-diene terpolymer), SB
R (styrene-butadiene rubber), NBR (acrylonitrile-butadiene rubber), fluorine rubber, polyvinyl acetate, polymethyl methacrylate, polyethylene, nitrocellulose and the like. The proportion of the binder in the positive electrode layer is usually 0.1% by weight or more, preferably 1% by weight or more, more preferably 5% by weight or more, usually 80% by weight or less, preferably 60% by weight or less, more preferably It is at most 40% by weight, most preferably at most 10% by weight. If the proportion of the binder is too low, the active material cannot be sufficiently retained, the mechanical strength of the positive electrode becomes insufficient, and the battery performance such as cycle characteristics may be deteriorated. Sometimes.

The positive electrode layer usually contains a conductive agent to increase conductivity. Examples of the conductive agent include graphite such as natural graphite and artificial graphite; carbon materials such as carbon black such as acetylene black; and amorphous carbon such as needle coke. The proportion of the conductive agent in the positive electrode is usually 0.01% by weight or more, preferably 0.1% by weight or more, more preferably 1% by weight or more, and usually 50% by weight or less, preferably 30% by weight or less, It is preferably at most 15% by weight. If the proportion of the conductive agent is too low, the conductivity may be insufficient, while if it is too high, the battery capacity may be reduced.

As the slurry solvent, an organic solvent which usually dissolves or disperses a binder is used.
For example, N-methylpyrrolidone, dimethylformamide, dimethylacetamide, methyl ethyl ketone, cyclohexanone, methyl acetate, methyl acrylate, diethyltriamine, NN-dimethylaminopropylamine, ethylene oxide, tetrahydrofuran and the like can be mentioned. Also, a dispersant, a thickener, etc. are added to
The active material can be slurried with latex such as BR.

The thickness of the positive electrode layer is usually 1 to 1000 μm,
Preferably it is about 10 to 200 μm. If it is too thick, the conductivity tends to decrease, and if it is too thin, the capacity tends to decrease. As a material of the current collector used for the positive electrode, aluminum, stainless steel, nickel-plated steel, or the like is used, and aluminum is preferable. The thickness of the current collector is usually 1 to 1000 μm, preferably 5 to 500 μm
It is about. If the thickness is too large, the capacity of the lithium secondary battery as a whole decreases, and if it is too small, the mechanical strength may be insufficient.

The positive electrode layer obtained by coating and drying is preferably compacted by a roller press or the like in order to increase the packing density of the active material. The lithium secondary battery of the present invention has a positive electrode using a lithium transition metal oxide that has undergone the above-mentioned processing steps as an active material, a negative electrode, and an electrolyte layer. Then, the compound is contained in at least one of the positive electrode, the negative electrode, and the electrolyte layer. As a result, a lithium secondary battery having excellent characteristics even in a high temperature environment can be obtained. The positive electrode active material and the positive electrode that have undergone the above-described processing steps are the same as described above.

The lithium transition metal oxide that has undergone the above-mentioned treatment step is considered to contribute to not only effectively suppressing the deterioration reaction at the positive electrode active material-electrolyte interface but also stabilizing the electrolyte itself and the negative electrode surface. It may be present anywhere in the negative electrode and the electrolyte layer, but is preferably contained in the positive electrode in order to sufficiently exhibit the effects of the present invention. This preferred embodiment can be regarded as a lithium secondary battery using the positive electrode containing the positive electrode material of the present invention. Accordingly, the ratio of the compound (A) to the lithium transition metal oxide in the preferred embodiment is the same as described above.

The active material of the negative electrode used for the negative electrode of the secondary battery of the present invention may be a lithium alloy such as lithium or a lithium-aluminum alloy alloy, but can absorb and release lithium with higher safety. Carbon materials are preferred. The carbon material is not particularly limited, and graphite, coal-based coke, petroleum-based coke, coal-based pitch carbide, petroleum-based pitch carbide, or those obtained by oxidizing these pitches, needle coke, pitch coke, phenolic resin And carbon materials such as crystalline cellulose, and carbon materials partially graphitized thereof, furnace black, acetylene black, pitch-based carbon fibers, and the like.

Further, SnO, SnO ₂ , Sn _1-x M _x O
(M = Hg, P, B, Si, Ge or Sb, where 0
≦ x <1), Sn ₃ O ₂ (OH) ₂ , Sn _3-x M _x O ₂ (O
H) ₂ (M = Mg, P, B, Si, Ge, Sb or M
n, where 0 ≦ x <3), LiSiO ₂ , SiO ₂ or L
iSnO _{2 and the} like can be mentioned. In addition, you may use as a mixture of 2 or more types selected from these.

The negative electrode is usually formed by forming a negative electrode layer on a current collector as in the case of the positive electrode. At this time, the same binder as that used for the positive electrode can be used as the binder used, the conductive agent and the slurry solvent used as needed. As the current collector of the negative electrode, copper, nickel, stainless steel, nickel-plated steel, or the like is used, and copper is preferably used.

When a separator is used between the positive electrode and the negative electrode, a microporous polymer film is used, and nylon, cellulose acetate, nitrocellulose, polysulfone, polyacrylonitrile, polyvinylidene fluoride, polypropylene, polyethylene, polybutene are used. Those made of a polyolefin polymer such as The chemical and electrochemical stability of the separator is an important factor. In this respect, a polyolefin-based polymer is preferable, and it is preferable that the battery is made of polyethylene from the viewpoint of the self-closing temperature, which is one of the purposes of the battery separator.

In the case of a polyethylene separator, ultrahigh molecular weight polyethylene is preferable from the viewpoint of maintaining high-temperature shape, and the lower limit of the molecular weight is preferably 500,000, more preferably 1,000,000, and most preferably 1.5 million. On the other hand, the upper limit of the molecular weight is preferably 5,000,000, more preferably 4,000,000, and most preferably 3,000,000. If the molecular weight is too large, the fluidity is too low and the pores of the separator may not be closed when heated.

As the electrolyte constituting the electrolyte layer in the lithium secondary battery of the present invention, for example, known organic electrolytes, polymer solid electrolytes, gel electrolytes, inorganic solid electrolytes and the like can be used. Organic electrolytes are preferred. The organic electrolyte is composed of an organic solvent and a solute. The organic solvent is not particularly limited, for example, carbonates, ethers, ketones, sulfolane compounds, lactones, nitriles, chlorinated hydrocarbons,
Ethers, amines, esters, amides, phosphate compounds and the like can be used. When these representatives are listed, dimethyl carbonate, diethyl carbonate, propylene carbonate, ethylene carbonate, vinylene carbonate, tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, 4-methyl-2-pentanone, 1,2- Dimethoxyethane, 1,2-diethoxyethane, γ-butyrolactone, 1,3-dioxolane, 4-methyl-1,3-dioxolane, diethyl ether, sulfolane, methylsulfolane, acetonitrile, propionitrile, benzonitrile, butyronitrile, Valeronitrile, 1,2-
A single solvent such as dichloroethane, dimethylformamide, dimethylsulfoxide, trimethyl phosphate, triethyl phosphate, or a mixture of two or more solvents can be used.

The above-mentioned organic solvent preferably contains a high dielectric constant solvent for dissociating the electrolyte. Here, the solvent having a high dielectric constant has a relative dielectric constant of 20 at 25 ° C.
The above compounds are meant. It is preferable that ethylene carbonate, propylene carbonate, and a compound in which a hydrogen atom thereof is replaced with another element such as halogen, an alkyl group, or the like in the high dielectric constant solvent be contained in the electrolytic solution. The proportion of the high dielectric constant compound in the electrolyte is preferably 2
It is at least 0% by weight, more preferably at least 30% by weight, most preferably at least 40% by weight. If the content of the compound is small, desired battery characteristics may not be obtained in some cases.

The solute to be dissolved in this solvent is not particularly limited, but any conventionally known solute can be used, and LiClO ₄ , LiAsF ₆ , LiPF ₆ , LiB
F ₄ , LiB (C ₆ H ₅ ) ₄ , LiCl, LiBr, CH ₃
SO ₃ Li, CF ₃ SO _3Li , LiN (SO ₂ CF ₃ ) ₂ ,
LiN (SO ₂ C ₂ F ₅ ) ₂ , LiC (SO ₂ CF ₃ ) ₃ , L
iN (SO ₃ CF ₃ ) _{2 and the} like, and at least one of them can be used. Also, C
A gas such as O ₂ , N ₂ O, CO, SO _2, or an additive such as polysulfide S _x ^2−, which can form a good film capable of efficiently charging and discharging lithium ions on the surface of the negative electrode, can be used alone at any ratio. Alternatively, it may be added to a mixed solvent.

When a polymer solid electrolyte is used, any known polymer may be used. In particular, a polymer having high ion conductivity with respect to lithium ions is preferably used. Polypropylene oxide, polyethyleneimine and the like are preferably used, and the polymer can be used as a gel electrolyte by adding the above solvent together with the above solute.

When an inorganic solid electrolyte is used,
Use of known crystalline and amorphous solid electrolytes for inorganic substances
Can be. Examples of the crystalline solid electrolyte include Li
I, Li_ThreeN, Li_{1 + x}M_xTi_2-x(PO_Four)_Three(M = A
l, Sc, Y, La), Li_{0.5- 3x}RE_{0.5 + x}TiO
_Three(RE = La, Pr, Nd, Sm) and the like.
As a crystalline solid electrolyte, for example, 4.9 LiI-34.1 L
i_TwoO-61B_TwoO_Five, 33.3Li_TwoO-66.7SiO_Two Etc. acid
Oxide glass and 0.45LiI-0.37Li_TwoS-0.26B_TwoS_Three,
0.30LiI-0.42Li_TwoS-0.28SiS_TwoEtc. sulfide gala
And the like. At least one or more of these
Can be used.

[0061]

EXAMPLES The method of the present invention will be described more specifically with reference to the following examples. [Preparation of lithium manganese composite oxide] Spinel type lithium manganese composite oxide Li [Mn _1.85 Al _0.11 Li _0.04 ] O ₄ was produced as follows.

Dimanganese trioxide (Mn ₂ O ₃ ), lithium carbonate (Li ₂ CO ₃ ), and boehmite (AlOOH)
And the molar ratio of each compound is 0.9
4: 0.52: 0.10 [molar ratio of Li: Mn: Al was 1.04: 1.88: 0.10]. This mixture was made into a uniform mixture using a jet mill. The obtained mixture is heated in air at 500 ° C. (heating rate: 5 ° C./min) and 600 ° C. (heating rate: 5 ° C./mi).
n), 700 ° C (heating rate: 5 ° C / min), 800 ° C
(Tempering rate: 5 ° C./min) sequentially for 6 hours, then 900 ° C. in the atmosphere (heating rate: 5 ° C./min)
For 24 hours, and then cooled to 300 ° C:
It was cooled at a rate of 0.2 ° C./min, then slowly cooled down to room temperature by natural cooling, and taken out. Elemental analysis showed that Li [Mn
_1.85 Al _0.11 Li _0.04 ] O ₄ was obtained.

Example 1 Li stored in a desiccator maintained at a relative humidity of 25%
_1.04Mn_1.85Al_0.11O _FourA part of the Mn site is L
Lithium having a cubic spinel structure substituted by i and Al
Manganese oxide at 120 ° C and 1 torr or less
For 1 hour to perform a drying treatment step,
2 moles of imidazole based on lithium manganese oxide
% And used as a positive electrode material.
The BET ratio of the lithium manganese oxide used here was
0.9m surface area^Two/ G, ultrasonic dispersion for 5 minutes,
The median diameter determined from the diffraction particle size distribution measurement is 7.4.
μm.

Comparative Example 1 The same lithium manganese oxide as in Example 1 was used as a positive electrode material without performing the drying treatment step and without adding or mixing the compound (A). Comparative Example 2 The same lithium manganese oxide as in Example 1 (relative humidity 2
5% stored in a desiccator)
A drying treatment step was not performed, and a mixture obtained by adding and mixing 4-nitroimidazole at a ratio of 2 mol% to lithium manganese oxide was used as a positive electrode material.

COMPARATIVE EXAMPLE 3 The same lithium manganese oxide as in Example 1 was used, kept at 120 ° C. and 1 torr or less for 1 hour to carry out a drying step, and then compound (A) was added. -It was used as a positive electrode material without mixing. Test Example (Evaluation of Battery) The batteries of Examples and Comparative Examples of the present invention were evaluated by the following methods.

1. Preparation of Positive Electrode and Confirmation of Capacity Positive electrode material 75% by weight, acetylene black 20% by weight, and polytetrafluoroethylene powder 5% by weight were weighed and thoroughly mixed in a mortar, and thinly sheet-shaped. And punched out with a 9 mmφ or 12 mmφ punch. At this time, the total weight was adjusted to be about 8 mmg and about 18 mg, respectively. This was pressed against an Al expanded metal to form a positive electrode.

Next, the capacity of the positive electrode was confirmed. That is, 9m
A battery cell was assembled with the positive electrode punched to mφ as a test electrode and Li metal as a counter electrode. 0.5 mA / c
m ² constant current charging, that is, a reaction for releasing lithium ions from the positive electrode was performed at an upper limit of 4.35 V, and then 0.5
A constant current discharge of mA / cm ² , that is, a test for absorbing lithium ions in the positive electrode was performed at a lower limit of 3.2 V. The initial charge capacity per unit weight of the positive electrode active material at this time is Qs (C) (m
Ah / g) and the initial discharge capacity was Qs (D) (mAh / g).

2. Preparation of Negative Electrode and Confirmation of Capacity A graphite powder (d002 = 3.35 °) having an average particle size of about 8 to 10 μm as a negative electrode active material and polyvinylidene fluoride as a binder were mixed in a weight ratio of 92.5: The mixture was weighed at a ratio of 7.5 and mixed in an N-methylpyrrolidone solution to prepare a negative electrode mixture slurry. 20 μm of this slurry
A negative electrode was applied to one side of a copper foil having a thickness, dried and evaporated to remove the solvent, punched out to a diameter of 12 mm, and pressed at 0.5 ton / cm ² .

A negative electrode active material was prepared by assembling a battery cell using the negative electrode as a test electrode and Li metal as a counter electrode, and performing a test at a lower limit of 0 V to occlude Li ions in the negative electrode at a constant current of 0.2 mA / cm ^2. The initial storage capacity per unit weight is Qf
(MAh / g). 3. Battery cell assembly Using a coin-shaped cell, battery performance was evaluated. That is,
Place the positive electrode punched to 12 mmφ on the positive electrode can,
A 25 μm porous polyethylene film was placed thereon as a separator, pressed with a polypropylene gasket, the negative electrode was placed, a spacer for thickness adjustment was placed, and a non-aqueous electrolyte solution of 1 mol / liter was added. Ethylene carbonate (EC) and lithium carbonate (DE) in which lithium fluorophosphate (LiPF ₆ ) is dissolved
A mixed solvent having a volume fraction of 3: 7 with C) was added to the inside of the battery to be sufficiently impregnated, and then a negative electrode can was placed thereon to seal the battery.

At this time, the balance between the weight of the positive electrode active material and the weight of the negative electrode active material is almost the same.

[0071]

## EQU1 ## Positive electrode active material amount [g] / negative electrode active material amount [g] =
(Qf / 1.2) / Qs (C) was set. 4. Test method In order to compare the high temperature characteristics of the battery obtained in this way, the 1 hour rate current value of the battery, that is, 1C, was measured.

[0072]

## EQU2 ## The following test was performed by setting 1 C [mA] = Qs (D) × amount of positive electrode active material [g] / [h]. First, a constant current of 0.
2C charge / discharge 2 cycles and constant current 1C charge / discharge 1 cycle are performed, and then constant current 0.2C charge / discharge 1 at a high temperature of 50 ° C.
Cycle and then 100 cycles of constant current 1C charge / discharge test. Note that the upper limit of charge is 4.2V and the lower limit voltage is 3.0.
V.

At this time, with respect to the discharge capacity Qh (1) in the first cycle in a 100 cycle test of 1C charge / discharge at 50 ° C.
The ratio of the discharge capacity Qh (100) at the 100th cycle is defined as the high-temperature cycle capacity maintenance rate P, that is,

[0074]

P [%] = {Qh (100) / Qh (1)} × 100, and the high-temperature characteristics of the batteries were compared using this value. The initial discharge capacity and the high-temperature cycle capacity retention ratio P in a 1C charge / discharge 100 cycle test at 50 ° C. in Examples and Comparative Examples.
Is shown in Table 1.

[0075]

[Table 1]

FIG. 1 shows a correlation diagram of the cycle-discharge capacity retention rate in the 50 ° C. cycle test in Example 1 and Comparative Examples 1 to 3. Comparing the example with the comparative example, it can be seen that the product of the present invention has improved cycle characteristics at high temperatures.

[0077]

Industrial Applicability According to the present invention, when a lithium transition metal oxide is used, a method for producing a positive electrode material for a lithium secondary battery improved so that deterioration in battery characteristics does not easily occur, and the positive electrode material and lithium secondary battery A positive electrode for a battery and a lithium secondary battery can be provided. As a result, variations in battery performance due to the storage environment of the lithium transition metal oxide can be suppressed.

[Brief description of the drawings]

FIG. 1 is a cycle-discharge capacity retention ratio correlation diagram in a 1C charge / discharge 100 cycle test at 50 ° C.

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) HA20

Claims (38)

[Claims] 1. After subjecting a lithium transition metal oxide to a heat treatment and / or a decompression treatment step, a compound (A) that can be adsorbed to an adsorption site on the surface of the treated lithium transition metal oxide is mixed. A method for producing a positive electrode material for a lithium secondary battery, comprising: (However, compound (A) is a compound that gives characteristics to the battery.) 2. The heating and / or depressurizing step comprises:
The method for producing a positive electrode material for a lithium secondary battery according to claim 1, wherein the state is maintained at a temperature of 00 to 200 ° C. and the atmospheric pressure or lower for 0.5 to 24 hours. 3. The lithium secondary battery according to claim 1, wherein the heat treatment and / or the decompression treatment step maintains the state at room temperature to 200 ° C. and 1 torr or less for 0.5 to 24 hours. A method for producing a positive electrode material for a battery. 4. The method according to claim 1, wherein the lithium transition metal oxide is 100-2.
A method for producing a positive electrode material for a lithium secondary battery, comprising: maintaining a state at 00 ° C. and the atmospheric pressure or lower for 0.5 to 24 hours, and then mixing a compound (A) capable of adsorbing to a hydroxyl group.
(However, compound (A) is a compound that gives characteristics to the battery.) 5. The method according to claim 1, wherein the lithium transition metal oxide is added at room temperature to 20.
A method for producing a positive electrode material for a lithium secondary battery, comprising maintaining a state of 0 ° C. and 1 torr or less for 0.5 to 24 hours, and then mixing a compound (A) capable of adsorbing to a hydroxyl group. (However, compound (A) is a compound that gives characteristics to the battery.) 6. After the heat treatment and / or the reduced pressure treatment step,
The method for producing a positive electrode material for a lithium secondary battery according to any one of claims 1 to 5, wherein a gas generated by the heat treatment and / or the pressure reduction treatment is exhausted. 7. After the heat treatment and / or the reduced pressure treatment,
The working process up to the completion of mixing of the compound (A) is the dew point-
The method for producing a positive electrode material for a lithium secondary battery according to claim 1, wherein the method is performed in a dry atmosphere at 30 ° C. or lower. 8. The positive electrode material for a lithium secondary battery according to claim 1, wherein the lithium transition metal oxide is a lithium manganese oxide having a spinel structure or a layered structure. Method. 9. The lithium transition metal oxide according to claim 1, wherein the lithium transition metal oxide is a lithium manganese oxide having a cubic spinel structure and a part of Mn sites substituted with another element. 3. The method for producing a positive electrode material for a lithium secondary battery according to 1.). 10. The surface hydroxyl groups are exposed by removing the physically adsorbed water on the surface of the lithium manganese oxide, and then the compound (A) capable of adsorbing the surface hydroxyl groups as an adsorption site is mixed with the compound (A). A) a method for producing a cathode material for a lithium secondary battery, wherein
(However, compound (A) is a compound that gives characteristics to the battery.) 11. The method according to claim 10, wherein the removal of the physically adsorbed water on the surface of the lithium manganese oxide is carried out by maintaining the temperature of 100 to 200 ° C. and the atmospheric pressure or less for 0.5 to 24 hours. A method for producing a positive electrode material for a lithium secondary battery as described above. 12. The method according to claim 10, wherein the removal of the physically adsorbed water on the surface of the lithium manganese oxide is performed by maintaining a state of room temperature to 200 ° C. and 1 torr or less for 0.5 to 24 hours. Method for producing a positive electrode material for a lithium secondary battery. 13. The positive electrode for a lithium secondary battery according to claim 1, wherein the compound (A) is a compound having a molecule having an unshared electron pair and / or a π electron. Material manufacturing method. 14. The compound (A) is a compound having at least one element selected from nitrogen, phosphorus, arsenic, antimony, oxygen, sulfur, selenium, tellurium, fluorine, chlorine, bromine, and iodine. Claims 1 to
14. The method for producing a positive electrode material for a lithium secondary battery according to any one of 13). 15. The compound (A) is a heterocyclic compound containing at least one or more atoms selected from nitrogen, oxygen, and sulfur as a hetero atom in a ring-constituting element. 15. The method for producing a positive electrode material for a lithium secondary battery according to any one of 14. 16. The lithium secondary battery according to claim 1, wherein the compounding amount of the compound (A) is 0.1 to 10 mol% based on the lithium transition metal oxide. A method for producing a positive electrode material for a battery. 17. After subjecting a lithium transition metal oxide to a heat treatment and / or a pressure reduction step, mixing a compound (A) adsorbable on an adsorption site on the surface of the lithium transition metal oxide after the treatment. Positive electrode material for lithium secondary batteries.
(However, compound (A) is a compound that gives characteristics to the battery.) 18. The heat treatment and / or the decompression treatment step,
0.5 to 24 at 100-200 ° C and below atmospheric pressure
The positive electrode material for a lithium secondary battery according to claim 17, wherein the positive electrode material is kept for a time. 19. The heat treatment and / or the decompression treatment step,
18. The positive electrode material for a lithium secondary battery according to claim 17, wherein a state of room temperature to 200 [deg.] C. and 1 torr or less is maintained for 0.5 to 24 hours. 20. A lithium transition metal oxide,
A positive electrode material for a lithium secondary battery in which a compound (A) that can be adsorbed on a hydroxyl group is mixed after being kept at 200 ° C. and at atmospheric pressure or lower for 0.5 to 24 hours. (However, compound (A) is a compound that gives characteristics to the battery.) 21. A method for preparing a lithium transition metal oxide from room temperature to 2
A positive electrode material for a lithium secondary battery, comprising a compound (A) that can be adsorbed on a hydroxyl group after being kept at 00 ° C. and 1 torr or less for 0.5 to 24 hours. (However, compound (A) is a compound that gives characteristics to the battery.) 22. The lithium secondary battery according to claim 17, wherein a gas generated by the heat treatment and / or the pressure reduction is exhausted after the heat treatment and / or the pressure reduction. For positive electrode material. 23. The work step after the heat treatment step and / or the pressure reduction step until the mixing of the compound (A) is completed is performed in a dry atmosphere having a dew point of −30 ° C. or less. 23. The positive electrode material for a lithium secondary battery according to any one of 17 to 22. 24. A method for removing a surface hydroxyl group by removing physically adsorbed water on the surface of a lithium manganese oxide, and then mixing a compound (A) capable of adsorbing the surface hydroxyl group as an adsorption site, thereby forming a compound (A) on the surface hydroxyl group. ) Is adsorbed on the positive electrode material for lithium secondary batteries. (However, compound (A) is a compound that gives characteristics to the battery.) 25. The method according to claim 24, wherein the removal of the physically adsorbed water on the surface of the lithium manganese oxide is carried out by maintaining the state at 100 to 200 ° C. and the atmospheric pressure or lower for 0.5 to 24 hours. The positive electrode material for a lithium secondary battery according to the above. 26. The method according to claim 24, wherein the removal of the physically adsorbed water on the surface of the lithium manganese oxide is performed by maintaining a state of room temperature to 200 ° C. and 1 torr or less for 0.5 to 24 hours. Positive electrode material for lithium secondary batteries. 27. Compound (A) on the surface of lithium manganese oxide via a hydroxyl group on the surface of lithium manganese oxide.
Is a positive electrode material for lithium secondary batteries. (However, compounds
(A) is a compound that gives characteristics to the battery. ) 28. The positive electrode for a lithium secondary battery according to claim 17, wherein the compound (A) is a compound having a molecule having an unshared electron pair and / or a π electron. material. 29. The compound (A) is a compound containing at least one element selected from nitrogen, phosphorus, arsenic, antimony, oxygen, sulfur, selenium, tellurium, fluorine, chlorine, bromine and iodine. 18. The method according to claim 17, wherein
29. The positive electrode material for a lithium secondary battery according to any one of items 28. 30. The compound according to claim 17, wherein the compound (A) is a heterocyclic compound containing at least one atom selected from nitrogen, oxygen and sulfur as a hetero atom in a ring constituent element. 30. The positive electrode material for a lithium secondary battery according to any of 29. 31. The lithium secondary battery according to claim 17, wherein the compounding amount of the compound (A) is 0.1 to 20 mol% based on the lithium transition metal oxide. Cathode material for battery. 32. The positive electrode material for a lithium secondary battery according to claim 17, wherein the lithium transition metal oxide is a lithium manganese oxide having a spinel structure or a layered structure. 33. The lithium transition metal oxide according to claim 17, wherein the lithium transition metal oxide is a lithium manganese oxide having a cubic spinel structure and a part of Mn sites substituted with another element. 4. The positive electrode material for a lithium secondary battery according to 4. 34. Other elements are Al, Ti, V, Cr, F
e, Li, Co, Ni, Cu, Zn, Mg, Ga, Zr
The positive electrode material for a lithium secondary battery according to claim 33, wherein the positive electrode material is selected from the group consisting of: 35. The positive electrode material for a lithium secondary battery according to claim 17, wherein the lithium manganese oxide has a BET specific surface area of 0.3 to 1.5 m ² / g. A positive electrode for a lithium secondary battery, comprising the positive electrode material for a lithium secondary battery according to any one of claims 17 to 35. 37. A lithium secondary battery comprising: a positive electrode containing the positive electrode material for a lithium secondary battery according to claim 17; a negative electrode; and an electrolyte. 38. The lithium secondary battery according to claim 37, wherein the active material of the negative electrode is a carbon material.