JP2005255433A - Lithium transition metal oxide for lithium battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lithium transition metal oxide having a layer structure and exhibiting more excellent cycle characteristic. <P>SOLUTION: The lithium transition metal oxide has the layer structure expressed by a composition formula Li<SB>1+X</SB>MO<SB>2</SB>, wherein M in the composition formula is composed of a transition metal containing Mn, Co and Ni in the atomic ratio of nearly 1:1:1, (x) being 0.01-0.5. When the lithium transition metal oxide is used as a positive active substance for a lithium battery, the ratio of change ä100-(z/y×100)} (%) of the lattice volume (z)(Å<SP>3</SP>) measured after charged up to 220 mAh/g charging capacity to the lattice volume (y)(Å<SP>3</SP>) before charged is ≤3.0% to stabilize the lattice volume, so that the lithium battery excellent in the cycle characteristic is obtained. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to a lithium transition metal oxide used as a positive electrode active material of a lithium battery such as a lithium primary battery, a lithium secondary battery, a lithium ion secondary battery, or a lithium polymer battery, particularly a lithium battery that can realize a lithium battery having excellent cycle characteristics. It relates to a transition metal oxide.

  Lithium batteries, especially lithium secondary batteries, are low in weight per unit of electricity and yet have high energy density, so they are used for driving in portable electronic devices such as video cameras, notebook computers, mobile phones, and electric vehicles. It is rapidly spreading as a power source.

The high energy density of the lithium secondary battery is mainly due to the potential of the positive electrode material. This type of positive electrode active material includes a spinel-structure lithium manganese oxide (LiMn ₂ O ₄ ) and a layered structure. Lithium composite oxides (LiM _x O _y ) such as LiCoO ₂ , LiNiO ₂ and LiMnO ₂ are known.
Most of the lithium secondary batteries currently on the market are LiCoO ₂ having a high voltage of 4 V as a positive electrode active material. However, since Co is very expensive, it has a similar layer structure as an alternative material for LiCoO ₂ , for example. Research and development of lithium composite oxide (LiM _x O _y ) has been actively promoted.

For example, in Patent Document 1, an alkaline solution is added to a mixed aqueous solution of manganese and nickel to co-precipitate manganese and nickel, lithium hydroxide is added, and then calcined to obtain the formula: LiNixMn1-xO2 A method for obtaining an active material represented by 7 ≦ x ≦ 0.95) is disclosed.
Patent Document 2 discloses a composition represented by the formula: LiNi _x M _1-x O ₂ (wherein M is at least one of Co, Mn, Cr, Fe, V, and Al, 1> x ≧ 0.5). A preferred particulate active material having an x is disclosed, and x = 0.15 is shown as the active material containing Ni and Mn.
Patent Document 3 discloses a formula synthesized by a coprecipitation synthesis method: Li _{y -x1} Ni _{1 -x} M _x O ₂ (wherein M is Co, Al, Mg, Fe, Mg or Mn, 0 <x2 ≦ 0.5, 0 ≦ x1 <0.2, x = x1 + x2, 0.9 ≦ y ≦ 1.3).
Patent Document 4 is composed of oxide crystal particles containing three kinds of transition metals, the crystal structure of the crystal particles is a layered structure, and the arrangement of oxygen atoms constituting the oxide is cubic close-packed, Li [Li _x ( _AP B _Q C _R ) _1-x ] O ₂ (wherein A, B and C are three different transition metal elements, −0.1 ≦ x ≦ 0.3, 0. 2 ≦ P ≦ 0.4, 0.2 ≦ Q ≦ 0.4, 0.2 ≦ R ≦ 0.4).
JP-A-8-171910 JP-A-9-129230 JP-A-10-69910 JP 2003-17052 A

In recent years, with improvement in performance of portable information electronic devices and the like, cycle characteristics have been strongly demanded, and development of a positive electrode active material capable of realizing cycle characteristics even better than conventional ones is strongly demanded.
Therefore, the present invention is to develop a positive electrode active material capable of realizing even more excellent cycle characteristics in a lithium transition metal oxide having a layer structure.

The present invention is a lithium transition metal oxide having a layer structure represented by the composition formula Li _{1 + x} MO ₂ , wherein M in the composition formula is approximately 1: 1: 1 of Mn, Co, and Ni. A lithium transition metal oxide comprising a transition metal contained in an atomic ratio and having a value of x of 0.01 to 0.5 is proposed.

When the lithium transition metal oxide of the present invention is used as a positive electrode active material of a lithium battery, after charging to a charge capacity of 220 mAh / g with respect to a lattice volume y (Å ³ ) before charging measured by XRD measurement. The characteristic is that the rate of change {100− (z / y × 100)} (%) of the measured lattice volume z (Å ³ ) is 3.0% or less.

Conventionally, a lithium transition metal oxide having a layer structure represented by a composition formula LiMO ₂ (M is a transition metal composed of Mn: Co: Ni = 1: 1: 1) is used as a positive electrode active material, and a lithium battery. When the XRD measurement is performed by extracting the positive electrode in the middle of charging and plotting the lattice volume obtained from the obtained lattice constant against the charging capacity, it is reported that the lattice volume greatly decreases in the vicinity of 180 mAh / g. (N. Yabuuchi, T. Ohzuku, Journal of Power Sources. 119-121 (2003) 171-174).
On the other hand, the lithium transition metal oxide of the present invention, that is, the Li ratio increased to Li / M = 1.01 to 1.5, compared to the Li / M = 1 lithium transition metal oxide, It was found that the change in the lattice volume during charging was remarkably small, and that the lattice volume was not significantly reduced to a charge / discharge capacity of about 250 mAh / g.
Therefore, the lithium transition metal oxide of the present invention not only has excellent cycle characteristics in a normal charge / discharge capacity region, but also can maintain structural stability up to a charge / discharge capacity of about 250 mAh / g. It can be used as a positive electrode active material for a lithium battery used in new applications that use up to the region of g.

In the present invention, the term “lithium battery” includes all batteries containing lithium or lithium ions in the battery, such as lithium primary batteries, lithium secondary batteries, lithium ion secondary batteries, and lithium polymer batteries.
Further, the upper and lower limits of the numerical range specified by the present invention are within the scope of the present invention as long as they have the same operational effects as those within the numerical range, even when slightly deviating from the specified numerical range. Includes intent to include.

The lithium transition metal oxide of the present invention is a lithium transition metal oxide having a layer structure represented by a composition formula Li _{1 + x} MO ₂ , wherein M in the composition formula is substantially composed of Mn, Co, and Ni. A lithium transition metal oxide comprising a transition metal having an atomic ratio of 1: 1: 1 and having a value of x of 0.01 to 0.5, that is, a composition formula Li _{1 + x} (Mn _{(1-x) / 3 Co} (1-x) / 3 Ni (1-x) / 3) O 2 ( lithium transition metal oxide having a layered structure represented by x = 0.01 to 0.5) It is.

  In the lithium transition metal oxide of the present invention, the ratio of Li to the transition metal, that is, Li / M is larger than the stoichiometric composition, among which 1.01 to 1.50, particularly preferably 1.03 to 1.30. Characterized by composition.

The transition metal M includes three elements of Mn, Co, and Ni, and includes Mn, Co, and Ni at an atomic ratio of approximately 1: 1: 1.
At the present stage, only knowledge about lithium transition metal oxides containing Ni, Co and Mn at a ratio of approximately 1: 1: 1 has been obtained, but the ratio of Ni, Co and Mn is 1: 1: 1. Since it is considered that the same result can be obtained even if it deviates slightly from the above, it is considered that the same effect can be obtained even with a lithium transition metal oxide in which the ratio of Ni, Co and Mn deviates by 10%. .

The lithium transition metal oxide of the present invention has a feature that the rate of change of the lattice volume after charging and discharging is remarkably small. That is, when the lithium transition metal oxide of the present invention was used as the positive electrode active material of a lithium battery, the battery was charged to a charge capacity of 220 mAh / g with respect to the lattice volume y (Å ³ ) before charging measured by XRD measurement. The rate of change | 100− (z / y × 100) | (%) of the lattice volume z (Å ³ ) measured later is 3.0% or less, preferably 2.5% or less. Detailed conditions in the lattice volume measurement are shown below.
Since the rate of change of the lattice volume during charge / discharge is thus small, the lithium transition metal oxide of the present invention is particularly excellent in structural stability and remarkably excellent in cycle characteristics when used as a positive electrode active material of a lithium battery. Lithium battery can be realized.

  Further, the lithium transition metal oxide of the present invention is excellent in structural stability up to the overcharge region because no significant decrease in the lattice volume is observed even when the charge / discharge capacity is increased to about 250 mAh / g. It is particularly excellent as a positive electrode active material for batteries for new applications to be used up to such a region.

(Production method)
The method for producing the lithium transition metal oxide of the present invention is not particularly limited. For example, it can be produced by a known production method (for example, the method described in [0022] to [0030] of JP-A No. 2003-17052). For example, a method in which a lithium salt compound, a nickel salt compound, a cobalt salt compound, and a manganese salt compound are dry-mixed at a predetermined ratio and fired, and a slurry in which a metal salt and optionally Li salt are mixed and dispersed in a wet manner is dried with a spray dryer or the like. A method of firing, a continuous wet synthesis method as disclosed in JP-A-2003-181639, a method of firing after drying, a chelating agent added to a mixed aqueous solution containing nickel ions, cobalt ions and manganese ions The lithium transition metal oxide of the present invention is produced by a conventionally known method such as a method of co-precipitation of these transition metals and mixing and firing the transition metal salt compound obtained by the coprecipitation and the lithium salt compound. However, it is preferable to use a coprecipitation method.

The coprecipitation method is a method of obtaining a composite oxide by simultaneously precipitating multiple elements in an aqueous solution using a neutralization reaction. In the production of the lithium transition metal oxide of the present invention, for example, nickel ions, Mixing a chelating agent and an alkaline solution in a mixed aqueous solution containing a predetermined amount of cobalt ions and manganese ions, and adjusting the pH of the mixed solution to a predetermined range causes co-precipitation of nickel ions, cobalt ions, and manganese ions to make a transition. What is necessary is just to obtain a metal salt compound, mix the obtained transition metal salt compound and lithium salt compound, and fire it under predetermined conditions.
Hereinafter, the manufacturing method using the coprecipitation method will be described in more detail.

  First, in order to obtain a transition metal salt compound in which the atomic ratio of manganese, nickel and cobalt is substantially 1: 1: 1, the atomic ratio of manganese, nickel and cobalt is substantially 1: 1: 1. Weighed manganese salt compound, nickel salt compound and cobalt salt compound are added to water, chelating agent solution (complexing agent) is added, alkali solution is added and reacted while adjusting pH of this reaction solution, nickel ions, Cobalt ions and manganese ions are coprecipitated to obtain transition metal salt compound particles.

In this case, the type of the manganese salt compound is not particularly limited, and for example, manganese sulfate, manganese nitrate, manganese chloride, and the like can be used, and manganese sulfate hydrate is particularly preferable.
The kind of the nickel salt compound is not particularly limited, and for example, nickel sulfate, nickel nitrate, nickel chloride and the like can be used. Among these, nickel sulfate hydrate is preferable.
The type of the cobalt salt compound is not particularly limited, and for example, cobalt sulfate, cobalt nitrate, cobalt chloride and the like can be used, and among these, cobalt sulfate hydrate is preferable.

  Examples of the chelating agent solution include ammonium ion suppliers (ammonium chloride, ammonium carbonate, ammonium fluoride, ammonium sulfate, ammonium nitrate, ammonia water, ammonia gas, etc.), hydrazine, glycine, glutamic acid, ethylenediaminetetraacetic acid, nitritotriacetic acid, uracil. Examples thereof include aminocarboxylic acids such as diacetic acid or salts thereof, and oxycarboxylic acids such as oxalic acid, malic acid, citric acid, and salicylic acid, or salts thereof. Among them, an aqueous ammonia solution is preferable.

  Examples of the alkali solution include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide. Among these, an aqueous sodium hydroxide solution is preferable.

  The pH of the reaction solution (mother liquor) is preferably adjusted to a range of 10.0 to 13.0, particularly 10.5 to 12.5. When the pH is less than 10.0, Ni ions in the solution are difficult to precipitate, and as a result, the composition deviation of the amount of metal ions in the precipitate is likely to occur. On the other hand, when the pH is higher than 13.0, the precipitate becomes fine particles, and cleaning and recovery operations become extremely difficult.

  Next, the transition metal salt compound thus obtained is dried, mixed with a lithium salt compound at a predetermined ratio, and fired.

Examples of the lithium salt compound include lithium hydroxide (LiOH), lithium carbonate (Li ₂ CO ₃ ), lithium nitrate (LiNO ₃ ), LiOH · H ₂ O, lithium oxide (Li ₂ O), other fatty acid lithium and lithium halogen. And the like. Of these, lithium hydroxide salts, carbonates and nitrates are preferred.

  The molar ratio of the lithium salt compound to the transition metal salt compound is 1.01 to 1.50, particularly preferably 1.03 to 1.0.1 in terms of the molar ratio of Li to the total number of transition metal elements (Li / M). Adjust to 30. At this time, if Li / M is less than 1.01, it becomes larger than the lattice volume change rate defined by the present invention, and the expected cycle characteristics cannot be obtained. On the other hand, when Li / M exceeds 1.5, not only a sufficient discharge capacity cannot be obtained, but also an impurity phase other than the layer structure material may appear, leading to a significant decrease in battery performance.

The method of mixing the lithium salt compound and the transition metal salt compound is not particularly limited as long as it can be uniformly mixed. For example, using a known mixer such as a mixer, the respective raw materials may be added simultaneously or in an appropriate order, followed by dry stirring and mixing.
If necessary, the mixed raw materials may be granulated to a predetermined size before firing. The granulation method may be wet or dry, and may be extrusion granulation, rolling granulation, fluid granulation, mixed granulation, spray drying granulation, pressure molding granulation, or flake granulation using a roll or the like. . However, when wet granulation is performed, it is necessary to sufficiently dry before firing. As a drying method, it may be dried by a known drying method such as spray heat drying, hot air drying, vacuum drying or freeze drying.

Firing is preferably performed in an air atmosphere, and is performed at 800 ° C. or higher, preferably 850 ° C. to 1000 ° C. for 1 hour to 30 hours, preferably 5 hours to 25 hours. Here, the firing temperature means the product temperature in the firing furnace.
As the baking furnace, a rotary kiln or a stationary furnace can be used.
The firing atmosphere may be an atmospheric atmosphere or an oxidizing atmosphere.
Further, annealing (heat treatment) may be performed at a specific temperature following firing.

When fired in this way, the composition formula Li _{1 + x} (Mn _{(1-x) / 3} Co _{(1-x) / 3} Ni _{(1-x) / 3} ) O ₂ (x = 0.01 to 0.5 And a transition metal oxide powder having a layer structure containing Ni, Co, and Mn as transition metals in a ratio of approximately 1: 1: 1 can be obtained.

The lithium transition metal oxide powder obtained by firing as described above can be effectively used as a positive electrode active material of a lithium battery after being crushed and classified as necessary. For example, a positive electrode mixture can be produced by mixing a lithium transition metal oxide, a conductive material made of carbon black or the like, and a binder made of Teflon (registered trademark) binder or the like.
Such a positive electrode mixture is used for the positive electrode, a material that can occlude and desorb lithium such as lithium or carbon is used for the negative electrode, and a lithium salt such as lithium hexafluorophosphate (LiPF6) is used for the non-aqueous electrolyte. A lithium battery can be formed using a material dissolved in a mixed solvent such as ethylene carbonate-dimethyl carbonate.

  Lithium batteries configured in this way are, for example, notebook computers, mobile phones, cordless phones, video movies, LCD TVs, electric shavers, portable radios, headphone stereos, backup power supplies, memory cards, and other electronic devices, pacemakers, hearing aids It can be used as a drive power source for medical equipment such as electric vehicles. Among them, mobile phones that require excellent cycle characteristics, portable computers such as PDAs (personal digital assistants) and notebook computers, electric vehicles (including hybrid vehicles), and power sources for power storage, etc. It is valid.

  Next, the present invention will be further described based on actually produced examples and comparative examples, but the present invention is not limited to the examples shown below.

(Method of battery evaluation)
Li battery evaluation was performed by the following method.
Accurately weighed 10.6 g of the positive electrode active material, 0.86 g of acetylene black (manufactured by Denki Kagaku Kogyo Co., Ltd.) and 8.6 g of a solution of 10 wt% PVdF (manufactured by Daikin Kogyo Co., Ltd.) in NMP (N-methylpyrrolidone) There, 10.8 g of NMP was added and mixed well to prepare a paste. This paste was placed on an aluminum foil as a current collector and formed into a coating film with an applicator adjusted to a gap of 150 μm, dried at 120 ° C. for 120 minutes, and then thickened with a roll press adjusted to a gap of 50 μm. Thereafter, a positive electrode was punched into Φ13 mm. Immediately before the battery was made, it was dried at 120 ° C. for 12 hours or more to remove water sufficiently and incorporated into the battery. In addition, the average weight of the aluminum foil having a diameter of 13 mm is obtained in advance, the weight of the positive electrode mixture is obtained by subtracting the weight of the aluminum foil from the weight of the positive electrode, and from the mixing ratio of the positive electrode active material, acetylene black and PVdF. The content of the positive electrode active material was determined. The negative electrode was made of metal Li having a diameter of 16 mm and a thickness of 0.6 mm, and these materials were used to produce a 2032 type coin battery shown in FIG.

In the coin battery of FIG. 1, a current collector 13 made of stainless steel is spot-welded inside a positive electrode case 11 made of stainless steel having organic electrolyte resistance. A positive electrode 15 made of the positive electrode mixture is pressure-bonded to the upper surface of the current collector 13. On the upper surface of the positive electrode 15, a separator 16 made of a microporous polypropylene resin impregnated with an electrolytic solution is disposed. In the opening of the positive electrode case 22, a sealing plate 12 having a negative electrode 14 made of metal Li bonded below is disposed with a gasket 17 made of polypropylene interposed therebetween, thereby sealing the battery. The sealing plate 12 serves as a negative electrode terminal and is made of stainless steel like the positive electrode case.
The battery diameter was 20 mm, and the total battery height was 3.2 mm. The electrolytic solution used was a mixture of ethylene carbonate and 1,3-dimethoxy carbonate in an equal volume, with 1 mol / L of LiPF ₆ dissolved as a solute in the solvent.

The charge / discharge conditions were as follows.
The charge / discharge voltage range was 3.0 to 4.3V. However, the charging voltage range when measuring the lattice volume during charging is not limited to this. A current value was calculated from the content of the positive electrode active material in the positive electrode so that the charge / discharge rate was 0.2 C, and the current was passed. Under these conditions, charge / discharge was repeated to calculate the cycle maintenance ratio relative to the initial discharge capacity. The measurement temperature was 25 ° C.

(Measurement method of lattice volume)
XRD measurement was performed with RINT2100 (manufactured by Rigaku Corporation), and the lattice constant for obtaining the lattice volume was determined by performing precise measurement of powder XRD and confirming that it was hexagonal (003) (101) ( 104), (105), (107), and (113), the a-axis length and the c-axis length were obtained from the six surface indices.
The lattice volume of the positive electrode before charging was measured as follows. As described above, the Li battery is assembled and charged / discharged for 3 cycles under the above charging / discharging conditions. The positive electrode terminated by discharging is taken out of the coin cell, thoroughly washed in DEC, and subjected to XRD measurement. The lattice constant was calculated and calculated as described above.
The lattice volume of the positive electrode during charging was measured as follows. As described above, the Li battery is assembled and charged and discharged for 3 cycles. After charging the specified charge capacity during the 4th cycle, the positive electrode is taken out of the coin cell and thoroughly washed in DEC, and XRD measurement is performed. Then, the lattice constant was obtained as described above, and the lattice volume was calculated.

(Example 1)
2.5L of city water is put in a 10L sealed container (with oil jacket) with a stirrer, 588g of manganese sulfate pentahydrate (manufactured by Yanagishima Pharmaceutical), cobalt sulfate hexahydrate (manufactured by Kansai Catalysts) 703 g and 762 g of nickel sulfate hexahydrate (manufactured by Mitsui Kinzoku Co., Ltd.) were dissolved, and water was added to adjust to 4 L. To this, 300 mL of 25 wt% aqueous ammonia (manufactured by Agata Pharmaceutical Co., Ltd.) was added, and 6 mol / L aqueous sodium hydroxide solution was added while stirring this solution, and the pH was adjusted to 11.5 using a pH meter. The bath temperature was kept at 45 ° C. and stirred for 12 hours. The precipitate after stirring is repeatedly decanted and washed until the conductivity of the supernatant becomes 1 mS or less, and then the reaction solution is solid-liquid separated by filtration, and the solid is dried at 120 ° C. for 10 hours to obtain a metal hydroxide raw material (above Corresponding to “transition metal salt compound”).
The number of moles of only the metal element of the metal hydroxide raw material is A mole, and the number of moles of Li element in the lithium carbonate is B / A = 1.03 so that B / A = 1.03. SQM) was weighed and mixed well with a ball mill to obtain a raw material mixed powder, and this raw material mixed powder was fired in the atmosphere at 900 ° C. for 20 hours to obtain a positive electrode active material.

  With respect to the obtained positive electrode active material, the lattice volume before charging and the lattice volume during charging were determined by the method described above, the lattice volume change rate was calculated, and the results are shown in Table 1. The results of the cycle characteristics are shown in FIG.

(Example 2)
The same metal hydroxide raw material and lithium carbonate as in Example 1 were weighed so that B / A = 1.10, and thoroughly mixed with a ball mill to obtain a raw material mixed powder. C. for 20 hours to obtain a positive electrode active material.
With respect to the obtained positive electrode active material, the lattice volume before charging and the lattice volume during charging were determined by the method described above, the lattice volume change rate was calculated, and the results are shown in Table 1. The results of the cycle characteristics are shown in FIG.

(Example 3)
The same metal hydroxide raw material and lithium carbonate as in Example 1 were weighed so that B / A = 1.20 and thoroughly mixed with a ball mill to obtain a raw material mixed powder. C. for 20 hours to obtain a positive electrode active material.
With respect to the obtained positive electrode active material, the lattice volume before charging and the lattice volume during charging were determined by the method described above, the lattice volume change rate was calculated, and the results are shown in Table 1. The results of the cycle characteristics are shown in FIG.

  Further, in FIG. 2, the lattice volume during charging was measured in small increments and plotted. Moreover, FIG. 3 is a charge curve when charge of the 4th cycle is performed to 270 mAh / g. The charging voltage at a charging capacity of 220 mAh / g is about 4.6 V. Even at this charging voltage, a small change rate of the lattice volume indicates that the positive electrode active material has excellent overcharge resistance.

Example 4
The same metal hydroxide raw material and lithium carbonate as in Example 1 were weighed so that B / A = 1.30, and thoroughly mixed with a ball mill to obtain a raw material mixed powder. C. for 20 hours to obtain a positive electrode active material.
With respect to the obtained positive electrode active material, the lattice volume before charging and the lattice volume during charging were determined by the method described above, the lattice volume change rate was calculated, and the results are shown in Table 1. The results of the cycle characteristics are shown in FIG.

(Comparative Example 1)
The same metal hydroxide raw material and lithium carbonate as in Example 1 were weighed so that B / A = 1.00, and thoroughly mixed with a ball mill to obtain a raw material mixed powder. C. for 20 hours to obtain a positive electrode active material.
With respect to the obtained positive electrode active material, the lattice volume before charging and the lattice volume during charging were determined by the method described above, the lattice volume change rate was calculated, and the results are shown in Table 1. The results of the cycle characteristics are shown in FIG.

In FIG. 2, the lattice volume during charging was measured in small increments and plotted. Compared with Example 3, the change in the lattice volume of Comparative Example 1 is significant, and in order to reduce the rate of change of the lattice volume, that is, to stabilize the structure of the positive electrode active material during charging, B / A In other words, in the composition formula Li _{1 + x} (Mn _{(1-x) / 3} Co _{(1-x) / 3} Ni _{(1-x) / 3} ) O ₂ , It is important to strictly control.

It is sectional drawing which shows the structure of the 2032 type coin battery produced for battery evaluation. It is the graph which compared the change of the lattice volume with respect to charge capacity about the positive electrode active material obtained in Example 3 and Comparative Example 1. It is the graph which showed the change of the voltage with respect to the charge curve of the 4th cycle about the positive electrode active material obtained in Example 3, ie, charge capacity. It is the graph which showed the relationship between the cycle number and cycle maintenance factor about each positive electrode active material obtained in Examples 1-4 and Comparative Example 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Positive electrode case 12 Sealing plate 13 Current collector 15 Positive electrode 16 Separator 14 Negative electrode 17 Gasket

Claims (8)

A lithium transition metal oxide having a layer structure represented by a composition formula Li _{1 + x} MO ₂ ,
M in the composition formula is composed of a transition metal containing Mn, Co and Ni at an atomic ratio of approximately 1: 1: 1, and the value of x is 0.01 to 0.5. Transition metal oxide. A positive electrode active material for a lithium battery using the lithium transition metal oxide according to claim 1,
Change rate of lattice volume z (Å ³ ) measured after charging to a charging capacity of 220 mAh / g with respect to lattice volume y (Å ³ ) before charging measured by XRD measurement {100− (z / y × 100)} (%) is 3.0% or less, The positive electrode active material for lithium batteries characterized by the above-mentioned.   The electrode for lithium batteries using the positive electrode active material of Claim 2.   The lithium battery using the electrode for lithium batteries of Claim 3 as a positive electrode.   A mobile phone using the lithium battery according to claim 4 as a driving power source.   A portable computer using the lithium battery according to claim 4 as a driving power source.   An electric vehicle using the lithium battery according to claim 4 as a driving power source. A power storage power source using the lithium battery according to claim 4 as a driving power source.

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