JP5196718B2 - Nonaqueous electrolyte secondary battery - Google Patents

Description

  The present invention relates to a non-aqueous electrolyte secondary battery, and more particularly, to a non-aqueous electrolyte secondary battery excellent in safety using a hexagonal lithium cobalt oxide containing a different element as a positive electrode active material.

  With the rapid spread of portable electronic devices, the required specifications for the batteries used for them are becoming stricter year by year, and in particular, small and thin, high capacity, excellent cycle characteristics, and stable performance are required. Yes. In the field of secondary batteries, lithium non-aqueous electrolyte secondary batteries, which have a higher energy density than other batteries, are attracting attention, and the proportion of lithium non-aqueous electrolyte secondary batteries shows a significant increase in the secondary battery market. ing.

  FIG. 1 is a perspective view showing a conventional cylindrical non-aqueous electrolyte secondary battery cut in the longitudinal direction. This nonaqueous electrolyte secondary battery 10 includes a spiral electrode body 14 in which a positive electrode plate 11 and a negative electrode plate 12 are wound via a separator 13, and insulating plates 15 and 16 above and below the spiral electrode body 14, respectively. Is placed in a steel cylindrical battery outer can 17 that also serves as a negative electrode terminal, and the current collecting tab 12a of the negative electrode plate 12 is welded to the inner bottom of the battery outer can 17 and the positive electrode plate 11 is collected. The electric tab 11a is welded to the bottom plate portion of the current interrupting sealing body 18 in which the safety device is incorporated, and a predetermined nonaqueous electrolyte is injected from the opening of the battery outer can 17. It is manufactured by sealing the can 17. Such a non-aqueous electrolyte secondary battery has an excellent effect of high battery performance and high battery reliability.

  As the negative electrode active material used in this non-aqueous electrolyte secondary battery, carbonaceous materials such as graphite and amorphous carbon have a discharge potential comparable to that of lithium metal or lithium alloy, but dendrite grows. Therefore, it is widely used because it has excellent properties such as high safety, excellent initial efficiency, good potential flatness, and high density.

  In addition, as the non-aqueous solvent of the non-aqueous electrolyte, carbonates, lactones, ethers, esters and the like are used alone or in combination of two or more, and among these, the dielectric constant is particularly high. Many carbonates which are large and have a high ionic conductivity of the non-aqueous electrolyte are used.

On the other hand, as the positive electrode active material, lithium composite oxides such as LiCoO ₂ (lithium cobaltate), LiNiO ₂ (lithium nickelate), LiMn ₂ O ₄ (lithium manganate), LiFeO ₂ (lithium ferrate) are carbon materials. It is known that a 4V class non-aqueous electrolyte secondary battery having a high energy density can be obtained by combining with a negative electrode comprising: Of these, lithium cobaltate is often used because various battery characteristics are superior to others. However, since cobalt is expensive and its abundance as a resource is small, this lithium cobaltate In order to continue to use as a positive electrode material for non-aqueous electrolyte secondary batteries, further enhancement of performance and lifetime of non-aqueous electrolyte secondary batteries are desired.

In order to further improve the performance and life of a non-aqueous electrolyte secondary battery using such lithium cobalt oxide as a positive electrode active material, it is essential to increase the capacity and safety of the battery. However, since lithium cobaltate, which is a positive electrode active material, is exposed to a potential of 4 V or more on the basis of lithium at the time of charging, it deteriorates due to elution of cobalt in lithium cobaltate when charging and discharging cycles are repeated, and load performance is reduced. The discharge capacity decreases with decreasing. Therefore, when synthesizing LiCoO ₂ that is a positive electrode active material, another transition element M is added and contained instead of cobalt to obtain a lithium-containing transition metal composite oxide represented by the general formula LiCo _1-x M _x O _2. Thus, many developments have been made so far in order to suppress the elution of cobalt and achieve various battery characteristics equivalent to or higher than those obtained when lithium cobaltate is used.

For example, Patent Document 1 below discloses an additive element coprecipitated cobalt oxide obtained by coprecipitation of a lithium compound and an additive element M as a positive electrode active material (however, the additive element M is Mg, Al, Cu, Zn). Using at least one selected from the above shows that a non-aqueous electrolyte secondary battery having a high active material specific capacity, excellent charge / discharge cycle characteristics, and capable of suppressing an increase in battery thickness can be obtained. ing. Similarly, in Patent Document 2 below, as a positive electrode active material, a general formula Li _x Co _y M _z O ₂ (wherein M is at least one element selected from Mg, Al, Si, Ti, Zn, Zr and Sn). When the Li-containing transition metal composite oxide represented by (2) is used, the phase transition is suppressed, the crystal structure is less disrupted, the thermal stability during charging is improved while maintaining high capacity, and good It has been shown that good charge / discharge characteristics can be realized. Furthermore, in Patent Document 3 below, the positive electrode active material is composed of particles of a complex oxide containing lithium and cobalt, and the complex oxide is an element M ¹ selected from the group consisting of Mg, Cu, and Zn; al, Ca, Ba, Sr, made from selected elements ^{M 2} Metropolitan from the group consisting of Y and Zr, the element ^{M 1} is uniformly distributed in the particle, the element ^{M 2} is than the interior of the particles By using a material that is widely distributed in the surface layer part, a non-aqueous electrolyte secondary battery that can achieve improved cycle life characteristics and thermal stability without reducing the tap density of the positive electrode active material can be obtained. It is shown.

Patent Document 4 below discloses a hexagonal lithium-containing cobalt composite oxide to which zirconium is added in an amount of 0.01 mol% or more and 0.9 mol% or less by coprecipitation during the synthesis of a cobalt compound as a positive electrode active material. It has been shown that, when used, a non-aqueous electrolyte secondary battery that can achieve improved cycle performance without lowering capacity or impairing safety is obtained. In Patent Document 5 below, as a positive electrode active material, zirconium is 0.01 to 1.0 mol%, magnesium is 0.01 to 3.0 mol%, and aluminum is 0.1 to 0.3 mol by coprecipitation. A general formula obtained by the synthesis of a cobalt compound as a cobalt source added with 01 to 3.0 mol% and a lithium compound as a lithium source is LiCo _1-x M _x O ₂ (M = Zr, Mg, Al ), A nonaqueous electrolyte secondary battery with improved thermal stability, load characteristics, and charge / discharge cycle characteristics can be obtained without reducing battery capacity. It has been shown.

JP 2002-198051 A (claims, paragraph [0082]) JP 2003-45426 A (Claims, paragraph [0087]) Japanese Patent Laying-Open No. 2004-47437 (Claims, paragraph [0087]) JP 2004-200101 A (claim, paragraph [0050]) Japanese Patent Laying-Open No. 2005-129489 (Claims, paragraph [0014])

  As described above, when a lithium-containing transition metal oxide containing other transition elements added during the synthesis of lithium cobaltate is used as the positive electrode active material, the cycle characteristics and heat are superior to those obtained when lithium cobaltate is used. It is known that a non-aqueous electrolyte secondary battery exhibiting stability, load characteristics, etc. can be obtained, but if the additive content of different elements is increased to further improve battery characteristics, crystal growth is Since it is obstructed, there is a problem that the battery capacity and safety are particularly likely to be lowered.

Based on the development status of the positive electrode active material for the non-aqueous electrolyte secondary battery as described above, the applicant of the present invention has the general formula disclosed in Patent Document 5 as the positive electrode active material, particularly LiCo _1-x M _When a hexagonal system lithium-containing cobalt composite oxide represented by xO ₂ (M = Zr, Mg, Al) is employed, various studies have been repeated to obtain a positive electrode active material that can achieve improved safety. As a result, by using a hexagonal system lithium cobalt oxide produced by using a cobalt compound further containing zinc to have a specific composition by a coprecipitation method, non-water having good thermal stability and excellent safety The inventors have found that an electrolyte secondary battery can be obtained, and have completed the present invention.

  That is, an object of the present invention is to provide a non-aqueous electrolyte secondary battery that uses a hexagonal lithium cobalt oxide containing a different element as a positive electrode active material and has good thermal stability and excellent safety. .

The above object of the present invention can be achieved by the following configurations. That is, the invention of the nonaqueous electrolyte secondary battery according to claim 1
In a nonaqueous electrolyte secondary battery comprising a positive electrode having a positive electrode active material, a negative electrode having a negative electrode active material, and a nonaqueous electrolyte,
The positive electrode active material, zirconium as different element, magnesium, cobalt compound containing the aluminum and zinc coprecipitated prepared as a raw material, Ri Do hexagonal lithium cobalt oxide,
The zirconium content in the hexagonal lithium cobalt oxide is 0.01 to 1.0 mol% with respect to the cobalt content, and the magnesium content is 0.01 to 3.0 mol% with respect to the cobalt content. the aluminum content is 0.01 to 3.0 mol% with respect to cobalt weight, further zinc content is characterized 0.01-3.0 mol% der Rukoto relative amount of cobalt.

That is, in the invention according to claim 1, four elements of zirconium, magnesium, aluminum, and zinc as different elements are simultaneously contained by coprecipitation when preparing a cobalt compound that is a raw material for synthesizing hexagonal lithium cobalt oxide. In this case, zirconium, magnesium, aluminum and zinc or these compounds as different elements are mixed with lithium cobalt oxide after firing, or lithium raw material, cobalt raw material, zirconium raw material and zinc raw material are mixed in a powder state. When it is fired (dry mixed firing), the predetermined effect cannot be obtained, but the predetermined effect is obtained by synthesizing hexagonal lithium cobalt oxide after simultaneously containing it in the cobalt compound by coprecipitation. become.
In addition, the positive electrode active material made of hexagonal lithium cobalt oxide has a zirconium content of 0.01 to 1.0 mol% with respect to the cobalt content, and a magnesium content of 0.01 to 3 with respect to the cobalt content. 0.0 mol%, when the aluminum content is 0.01 to 3.0 mol% with respect to the cobalt content, and when the zinc content is 0.01 to 3.0 mol% with respect to cobalt It has a good effect.
That is, as disclosed in Patent Document 5, zirconium is 0.01 to 1.0 mol% and magnesium is 0.01 to 3.0 mol based on the amount of cobalt by coprecipitation as a positive electrode active material synthesis raw material. % And a cobalt compound containing 0.01 to 3.0 mol% of aluminum is used as a raw material, a nonaqueous electrolyte secondary battery excellent in battery capacity, cycle characteristics and safety is obtained. Furthermore, it has been found and limited that the optimum range of zinc content is 0.01 to 3.0 mol%. If the zinc content is 0.01 mol% or more, the thermal stability of the battery will be good and the safety will be excellent, but if it exceeds 3.0 mol%, the battery capacity will be reduced.

  In the present invention, carbonates, lactones, ethers, esters and the like can be used as the nonaqueous solvent (organic solvent) constituting the nonaqueous electrolyte secondary battery. A mixture of the above can also be used. Among these, carbonates, lactones, ethers, ketones, esters and the like are preferable, and carbonates are more preferably used.

  Specific examples include ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), vinylene carbonate (VC), cyclopentanone, sulfolane, 3-methylsulfolane, 2,4-dimethylsulfolane, 3-methyl. -1,3-oxazolidine-2-one, dimethyl carbonate (DMC), methyl ethyl carbonate (MEC), diethyl carbonate (DEC), methyl propyl carbonate, methyl butyl carbonate, ethyl propyl carbonate, ethyl butyl carbonate, dipropyl carbonate, γ -Butyrolactone, γ-valerolactone, 1,2-dimethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxolane, methyl acetate, ethyl acetate, 1,4-dio Xanthan can be mentioned. In the present invention, a mixed solvent containing EC is preferably used from the viewpoint of improving the charge / discharge efficiency. However, since cyclic carbonate is generally easily oxidized and decomposed at a high potential, the EC content in the non-aqueous solvent is 5% by volume or more and 25% by volume. % Or less is preferable.

In addition, as a solute of the nonaqueous electrolyte solution in the present invention, a lithium salt generally used as a solute in a nonaqueous electrolyte secondary battery can be used. Such lithium salts include LiPF ₆ , LiBF ₄ , LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , LiN (CF ₃ SO ₂ ) (C ₄ F ₉ SO ₂ ), LiC (CF ₃ SO ₂ ) ₃ , LiC (C ₂ F ₅ SO ₂ ) ₃ , LiAsF ₆ , LiClO ₄ , Li ₂ B ₁₀ Cl ₁₀ , Li ₂ B ₁₂ Cl ₁₂ , and mixtures thereof Illustrated. Among these, LiPF ₆ (lithium hexafluorophosphate) is preferably used. When charged with a high charging voltage, becomes easily dissolved aluminum which is generally used as a current collector for the positive electrode, in the presence of LiPF _6, by the LiPF ₆ is decomposed, the aluminum surface coating formed Thus, dissolution of aluminum can be suppressed by this coating. Therefore, it is preferable to use LiPF ₆ as the lithium salt. The amount of solute dissolved in the non-aqueous solvent is preferably 0.5 to 2.0 mol / L. In addition, a non-aqueous electrolyte in which these non-aqueous solvent and solute are contained in an appropriate polymer to form a gel can be used.

  The invention according to claim 2 is the nonaqueous electrolyte secondary battery according to claim 1, wherein the cobalt compound is cobalt carbonate or cobalt hydroxide containing zirconium, magnesium, aluminum, and zinc by coprecipitation. It is characterized by that.

The invention according to claim 3 is the nonaqueous electrolyte secondary battery according to claim 1 or 2 , wherein the negative electrode active material is made of a carbonaceous material. As the carbonaceous material, at least one selected from natural graphite, artificial graphite, carbon black, coke, glassy carbon, carbon fiber, or a fired body thereof can be used.

  According to the first aspect of the present invention, as will be described in detail based on the following examples and comparative examples, a nonaqueous electrolyte secondary battery having good thermal stability and excellent safety can be obtained.

  Further, according to the invention according to claim 2, as a cobalt compound for synthesizing a positive electrode active material comprising lithium cobaltate containing a different element, a cobalt compound other than cobalt carbonate and cobalt hydroxide can be used for the time being. Cobalt or cobalt hydroxide is preferred because it can be coprecipitated homogeneously and efficiently together with zirconium, magnesium, aluminum and zinc, and the production method is simple and inexpensive.

According to the invention of claim 3 , the battery voltage is indicated by the difference between the positive electrode potential and the negative electrode potential, and the battery capacity can be increased by increasing the battery voltage. When a carbonaceous material having a low potential (about 0.1 V based on lithium, such as natural graphite or artificial graphite) is used, a nonaqueous electrolyte secondary battery having a high battery voltage and a high utilization rate of the positive electrode active material can be obtained.

  Hereinafter, the best mode for carrying out the present invention will be described in detail using examples and comparative examples. However, the following examples illustrate one example of a nonaqueous electrolyte secondary battery for embodying the technical idea of the present invention, and are intended to specify the present invention in this example. Rather, the present invention can be equally applied to a variety of modifications without departing from the technical idea shown in the claims.

[Examples 1 to 3, Reference Example 1 ]
First, a specific method for manufacturing a nonaqueous electrolyte secondary battery common to all of Examples 1 to 3 and Reference Example 1 will be described.
[Production of positive electrode]
The heterogeneous element-containing lithium cobalt oxide was produced as follows. First, after adding a solution of zirconium, magnesium, aluminum and zinc dissolved in an acid to a solution in which cobalt is dissolved in an acid (for example, sulfuric acid), zirconium hydrogen, magnesium, aluminum and Cobalt carbonate co-precipitated with zinc was obtained. Thereafter, the cobalt carbonate co-precipitated with zirconium, magnesium, aluminum and zinc was subjected to a thermal decomposition reaction in the presence of oxygen, and zirconium, magnesium, aluminum and zinc as starting materials for the cobalt source were coprecipitated. Tricobalt oxide was obtained.

  Next, lithium carbonate was used as a starting material for the lithium source, and lithium cobalt and tricobalt tetroxide containing zirconium, magnesium, aluminum and zinc were co-precipitated so that the molar ratio of lithium to cobalt was 1: 1. Weighed. Next, after mixing these compounds in a mortar, the resulting mixture was fired in air at 850 ° C. for 20 hours to synthesize a hexagonal lithium cobalt oxide fired body containing zirconium, magnesium, aluminum and zinc. . Thereafter, the synthesized fired body was pulverized until the average particle size became 10 μm to obtain a positive electrode active material. The contents of zirconium, magnesium, aluminum and zinc in the obtained positive electrode active material were determined by analysis by ICP (Inductively Coupled Plasma) emission analysis.

  85 parts by mass of the positive electrode active material powder made of hexagonal lithium cobaltate co-precipitated with zirconium, magnesium, aluminum and zinc obtained as described above, 10 parts by mass of carbon powder as a conductive agent, A polyvinylidene fluoride powder as an adhesive was mixed so as to be 5 parts by mass, and this was mixed with an N-methylpyrrolidone (NMP) solution to prepare a slurry. This slurry was applied on both sides of an aluminum current collector having a thickness of 20 μm by a doctor blade method and dried to form active material layers on both sides of the positive electrode current collector. Then, it compressed to 160 micrometers in thickness using the compression roller, and produced the positive electrode whose short side length is 55 mm and whose long side length is 500 mm.

  As disclosed in Patent Document 5, when zirconium, magnesium, aluminum and zinc are contained as a positive electrode active material synthesis raw material by coprecipitation, the zirconium content is 0.01 to 1.0 mol relative to the cobalt amount. %, Magnesium is 0.01 to 3.0 mol% and aluminum is 0.01 to 3.0 mol%, so that the positive electrode active materials according to Examples 1 to 3 contain zirconium. The amount was 0.5 mol%, the magnesium content was 1.0 mol%, and the aluminum content was 1.0 mol%.

[Production of negative electrode]
A natural graphite powder is mixed in an amount of 95 parts by mass and a polyvinylidene fluoride powder is mixed in an amount of 5 parts by mass. This is mixed with an NMP solution to prepare a slurry, and the slurry is mixed on both sides of a copper current collector having a thickness of 18 μm. The active material layer was formed on both surfaces of the negative electrode current collector by applying and drying the film on the surface of the negative electrode current collector. Then, it compressed to 155 micrometers using the compression roller, and produced the negative electrode whose length of a short side is 57 mm, and whose length of a long side is 550 mm. The potential of graphite is 0.1 V with respect to lithium. Also, the active material filling amount of the positive electrode and the negative electrode is determined based on the charge capacity ratio of the positive electrode and the negative electrode (negative electrode charge capacity / positive electrode) at the voltage of the positive electrode active material (for example, the full charge potential is 4.3 V based on the lithium metal). The charge capacity was adjusted to 1.1.

[Preparation of electrolyte]
LiPF ₆ was dissolved in an equal volume mixed solvent of ethylene carbonate and diethyl carbonate at a rate of 1 mol / L to prepare an electrolyte solution, which was used for battery production.

[Production of battery]
Cylindrical non-aqueous electrolyte secondary batteries (65 mm in height and 18 mm in diameter) of Examples 1 to 3 were prepared using the above positive electrode, negative electrode, and electrolytic solution, and using a polypropylene microporous membrane as a separator.

[Comparative Examples 1-3]
The batteries of Comparative Examples 1 to 3 were produced in the same manner as in Examples 1 to 3 and Reference Example 1 except that the magnesium, aluminum, and zinc to be added were changed in [Production of Positive Electrode].

[Comparative Example 4]
Further, the battery of Comparative Example 4 was obtained in Example 1 except that, in [Preparation of positive electrode], tricobalt tetroxide and lithium carbonate were mixed and contained (dry-type inclusion) without adding zinc by coprecipitation. -3, produced in the same manner as in Reference Example 1 .

[Measurement of initial battery capacity]
About each battery of Examples 1-3 manufactured as mentioned above , Reference Example 1, and Comparative Examples 1-4, after charging with a constant current of 1500 mA at 25 ° C., the voltage of the battery became 4.2V Was initially charged at a constant voltage of 4.2 V until the charge current value reached 30 mA. The initially charged battery was discharged at a constant current of 1500 mA until the battery voltage reached 2.75 V, and the discharge capacity at this time was determined as the initial capacity.

[Measurement of DSC heat generation start temperature]
For all the batteries of Examples 1 to 3, Reference Example 1 and Comparative Examples 1 to 4, the battery was charged at 25 ° C. until it reached 4.3 V at a current value of 30 mA, then decomposed in a dry box and washed with dimethyl carbonate. Then, it vacuum-dried and set it as the sample. 10 mg of ethylene carbonate is added to 40 mg of each sample, sealed in an aluminum cell under an argon atmosphere, and heated at 5 ° C./min with a differential scanning calorimeter to start self-heating. Was measured. Incidentally, the lithium cobalt oxide in the non-aqueous electrolyte secondary battery is decomposed when exposed to high temperature, and the battery becomes abnormal. The DSC exotherm start temperature indicates a temperature at which the positive electrode active material starts to decompose, and the higher the exotherm start temperature, the more stable lithium cobalt oxide is present, that is, the higher the safety of the battery. .

[Measurement of C-axis lattice constant]
By filling each positive electrode active material powder sample of Example 2, Comparative Examples 1, 2 and 3 into a powder X-ray diffraction glass plate, and performing X-ray diffraction measurement by CuKα1 line (λ = 1.5406Å), The lattice constant was determined.

The above measurement results are shown in Tables 1 to 3 organized for each composition of different elements.

[Zinc content]
The zirconium content is constant at 0.5 mol%, the magnesium content is constant at 1.0 mol%, the aluminum content is constant at 1.0 mol%, and the zinc content is changed from 0 mol% to 4.0 mol%. The following can be understood from the results of Table 1 that summarize the results of the cases. That is, by setting the zinc content to 0.01 mol% or more (Examples 1 to 3, Reference Example 1 ), the DSC heat generation temperature rises as compared with the battery of Comparative Example 1 in which zinc is not added. Safety is improved. In Reference Example 1 having a zinc content of 4.0 mol%, a good DSC exothermic temperature was obtained, but the battery initial capacity was lowered. In addition, in the battery of Comparative Example 1 in which zinc was not added, a good initial capacity was obtained, but the DSC heat generation temperature was low and the safety was poor .

[About the effect of zinc content]
When the zirconium content is constant at 0.5 mol% and neither magnesium, aluminum nor zinc is contained (Comparative Example 2), when magnesium or aluminum is not contained and zinc is 1.0 mol% (Comparative Example 3), The following can be understood from the results of Table 2 showing the results of measuring the C-axis lattice constant for the cases of Comparative Example 1 and Example 2 described above. That is, in the case where magnesium and aluminum are not coprecipitated, the C-axis lattice constant does not change even when zinc is contained (Comparative Example 3) as compared with the case where zinc is not contained (Comparative Example 2). DSC exothermic temperature does not rise either. Further, when magnesium and aluminum are co-precipitated, the C-axis lattice constant is slightly increased and the DSC exothermic temperature is also increased even if zinc is not co-precipitated simultaneously (Comparative Example 1). However, when co-precipitated with magnesium and aluminum and co-precipitated with zinc (Example 2), the C-axis lattice constant is remarkably increased and the DSC exothermic temperature is also remarkably increased.

  Although this has not yet been clarified in detail, it is considered that when magnesium and aluminum are present, the thermal stability is improved by the solid solution of zinc in the lithium cobaltate structure. Therefore, in the present invention, in order to achieve both high thermal stability and battery capacity at a high level, therefore, in the nonaqueous electrolyte secondary battery of the present invention, zirconium, magnesium, aluminum and zinc are co-precipitated as different elements. It is necessary to use a positive electrode active material composed of hexagonal lithium cobalt oxide synthesized from a cobalt compound contained in the above.

[About the coprecipitation of zinc]
The coprecipitation-containing zirconium content is 0.5 mol%, the coprecipitation-containing magnesium coprecipitation content is 1.0 mol%, and the coprecipitation content aluminum content is 1.0 mol%, and the zinc content is constant. From the results of Table 3 when changed to 0 mol% (Comparative Example 1), 3.0 mol% coprecipitation (Example 3), and 3.0 mol% dry content (Comparative Example 4), the following is obtained. I understand. That is, the DSC exothermic temperature markedly increases when zinc is coprecipitated (Example 3) as compared to the case where zinc is not contained (Comparative Example 1), but the case where zinc is contained dry (Comparative Example 4). ) DSC exothermic temperature does not change. Accordingly, even from the results shown in Table 3, in the non-aqueous electrolyte secondary battery of the present invention, a cobalt compound containing zirconium, magnesium, aluminum, and zinc added by coprecipitation as different elements is used as a raw material. It can be confirmed that it is necessary to use a positive electrode active material made of synthesized hexagonal lithium cobalt oxide.

In Examples 1 to 3 and Reference Example 1 , examples in which these metals were dissolved in acid as starting materials for cobalt, zirconium, magnesium, aluminum and zinc were shown. Water-soluble salts such as Further, in Examples 1 to 3 and Reference Example 1 , an example in which carbonate was used as a cobalt compound containing zirconium, magnesium, aluminum and zinc by coprecipitation was shown. It can also be used.

It is a perspective view which cuts the cylindrical nonaqueous electrolyte secondary battery produced conventionally from the lengthwise direction.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Nonaqueous electrolyte secondary battery 11 Positive electrode plate 12 Negative electrode plate 13 Separator 14 Spiral electrode body 15, 16 Insulating plate 17 Battery outer can 18 Current interruption sealing body

Claims (3)

In a nonaqueous electrolyte secondary battery comprising a positive electrode having a positive electrode active material, a negative electrode having a negative electrode active material, and a nonaqueous electrolyte,
The positive electrode active material, zirconium as different element, magnesium, cobalt compound containing the aluminum and zinc coprecipitated prepared as a raw material, Ri Do from lithium cobalt oxide hexagonal,
The zirconium content in the hexagonal lithium cobalt oxide is 0.01 to 1.0 mol% with respect to the cobalt content, and the magnesium content is 0.01 to 3.0 mol% with respect to the cobalt content. the aluminum content is 0.01 to 3.0 mol% with respect to cobalt weight, further zinc content non characterized by 0.01 to 3.0 mol% der Rukoto with cobalt amount Water electrolyte secondary battery.   The nonaqueous electrolyte secondary battery according to claim 1, wherein the cobalt compound containing zirconium, magnesium, aluminum, and zinc as the different elements by coprecipitation is cobalt carbonate or cobalt hydroxide. The non-aqueous electrolyte secondary battery according to claim 1 or 2, wherein the negative active material is characterized by comprising the carbonaceous material.

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