JP5482977B2 - Non-aqueous electrolyte secondary battery lithium cobalt oxide particle powder, method for producing the same, and non-aqueous electrolyte secondary battery - Google Patents

Description

  The present invention provides a lithium cobalt oxide particle powder excellent in load characteristics, cycle characteristics, and thermal stability.

  In recent years, electronic devices such as AV devices and personal computers are rapidly becoming portable and cordless, and there is an increasing demand for secondary batteries having a small size, light weight, and high energy density as power sources for driving these devices. Under such circumstances, a lithium ion secondary battery having advantages such as a high charge / discharge voltage and a large charge / discharge capacity has attracted attention.

Conventionally, as positive electrode active substances useful for high energy-type lithium ion secondary batteries having 4V-grade voltage, LiMn ₂ O ₄ of spinel structure, LiMnO ₂ having a zigzag layer structure, LiCoO ₂ of layered rock-salt structure, LiCo _1-X Ni _X O ₂ , LiNiO _{2 and the} like are generally known, and among them, a lithium ion secondary battery using LiCoO ₂ is excellent in that it has a high charge / discharge voltage and charge / discharge capacity. There is a need for further improvement in characteristics.

That is, when LiCoO ₂ pulls out lithium, Co ³⁺ becomes Co ^{4+ and} yarn teller distortion occurs, and in the region where Li is pulled 0.45, from hexagonal to monoclinic, when further drawn, it changes from monoclinic to hexagonal. The crystal structure changes. Therefore, by repeating the charge / discharge reaction, the crystal structure becomes unstable, and oxygen release, reaction with the electrolytic solution, and the like occur.

  Furthermore, since the reaction with the electrolytic solution becomes active at high temperatures, the structure of the positive electrode active material is stable even at high temperatures and thermal stability needs to be improved to ensure safety as a secondary battery. Has been.

Therefore, lithium cobalt oxide (LiCoO ₂ ) that is stable at load characteristics, cycle characteristics, and high temperature and high voltage is required.

  Conventionally, a technique for replacing or coating with a Zr compound for stabilizing lithium cobaltate has been proposed. A method of previously containing Zr in a cobalt raw material (Patent Documents 1 to 5), a cobalt raw material, a zirconium raw material, and a lithium raw material Are simultaneously mixed and fired (Patent Documents 6 to 11), and a lithium cobaltate particle powder is coated with a Zr compound (Patent Document 12).

JP 2004-200101 A JP 2004-299975 A JP 2004-311408 A Japanese Patent Laid-Open No. 2005-129489 JP 2005-190900 A JP-A-4-319260 JP 2001-68167 A JP 2002-356330 A JP 2002-358963 A Japanese Patent Laid-Open No. 2005-50779 JP 2005-85635 A JP 2003-221234 A

  A positive electrode active material and cobalt oxide particle powder satisfying the above-mentioned properties are currently most demanded, but have not yet been obtained.

  When a Zr element is contained in a cobalt raw material as described in the aforementioned Patent Documents 1 to 5, a Zr compound is likely to be present in lithium cobaltate particles, and it is difficult to say that the surface modification effect is sufficient.

Moreover, when adding a Zr compound when mixing with a lithium raw material as described in the aforementioned Patent Documents 6 to 11, if the particle size of the cobalt oxide raw material is too large, the Zr compound is produced alone, and cobalt acid The surface modification effect of lithium becomes insufficient. Further, when the Zr compound is made into fine particles, the Zr compound tends to remain inside the particles as shown in the prior arts of Patent Documents 1 to 5.
When uniformly distributed inside the particles, Zr is not substituted into the lithium cobaltate crystal structure, so the crystallinity of lithium cobaltate is reduced and the thermal stability is not only reduced, but also the surface Therefore, the cycle characteristics and durability at a high voltage are not improved.

  Further, in the method of mixing Zr compound with lithium cobalt oxide particle powder as described in Patent Document 12 and firing at 200 to 700 ° C., the bond between the lithium cobalt oxide particle interface and the Zr compound is weak and sufficient. It is difficult to obtain an excellent surface modification effect.

  The technical problem can be achieved by the present invention as follows.

That is, the present invention is a lithium cobaltate particle powder used as a positive electrode active material of a nonaqueous electrolyte secondary battery, the lithium cobaltate particle powder is a lithium cobaltate particle powder coated with a Zr compound, The Zr compound does not exist inside the particle but is localized on the surface, the chemical formula of the Zr compound is represented by Li ₂ ZrO ₃ , and the Zr content is 0.05 to 1.0 wt% with respect to the whole particle. The lithium cobalt oxide particle powder coated with the Zr compound is characterized in that the average particle size of the primary particles of the Zr compound is 1.0 μm or less (Invention 1).

The present invention also relates to a method for producing a lithium cobaltate particle powder coated with a Zr compound in which a cobalt raw material, a zirconium raw material, and a lithium raw material are mixed and fired. it is a manufacturing method of the present invention 1 Symbol placement lithium cobaltate particles coated with Zr compound of wherein the average particle size of is less cobalt oxide 1.0 .mu.m (the present invention 2).

The present invention also relates to a method for producing a lithium cobaltate particle powder coated with a Zr compound in which a cobalt raw material, a zirconium raw material, and a lithium raw material are mixed and fired. The average particle size of cobalt oxide is 1.0 μm or less, and the average particle size of the behavior particles measured by the laser particle size distribution measuring apparatus of the zirconium raw material is 1.0 μm or less. This is a method for producing lithium cobaltate particle powder coated with the Zr compound according to the present invention 2 (present invention 3 ).

Further, the present invention is a cobalt oxide whose average particle size is 0.5 μm or less as measured by a laser-based particle size distribution measuring apparatus for cobalt raw material, and behavior measured by a laser-based particle size distribution measuring apparatus for zirconium raw material. The method for producing a lithium cobaltate particle powder coated with a Zr compound according to the present invention 3 , wherein the average particle diameter of the particles is zirconium oxide having a particle diameter of 0.8 μm or less (the present invention 4 ).

Moreover, the present invention provides any one of the present inventions 2 to 4 , wherein the cobalt raw material is cobalt oxide containing at least one element selected from Ni, Mn, Si, Sn, Ti, Mg, and Al. 3 is a method for producing a lithium cobaltate particle powder coated with a Zr compound described in ( 5 ).

Further, the present invention is a nonaqueous electrolyte secondary battery using lithium cobaltate particles coated with Zr compound of the present invention 1 Symbol placement as a cathode active material or a portion thereof (invention 6).

  Since the lithium cobalt oxide particle powder according to the present invention is excellent in load characteristics, cycle characteristics and thermal stability, it is suitable as a positive electrode active material for a non-aqueous electrolyte secondary battery.

  As a result of examining the stabilization by the Zr compound, the surface activity can be suppressed without deteriorating the electrochemical properties of the lithium cobaltate by depositing the Zr compound on the surface of the lithium cobaltate in the growth stage from the production of the lithium cobaltate. .

  The configuration of the present invention will be described in more detail as follows.

  First, the lithium cobalt oxide particle powder coated with the Zr compound according to the present invention will be described.

In the lithium cobalt oxide particle powder coated with the Zr compound according to the present invention, the Zr compound does not exist inside the lithium cobalt oxide particle and the Zr compound exists on the particle surface.
When a Zr compound is present inside the particle, Zr is not substituted into the crystal structure of the lithium cobaltate particle, so the crystallinity of the lithium cobaltate is lowered and the thermal stability is reduced. In addition, since the activity of the surface is not suppressed, the cycle characteristics and durability at a high voltage are not improved.

  In addition, 0.05 to 5.0 mol% of one or more elements selected from Ni, Mn, Si, Sn, Ti, Mg, or Al are contained inside the lithium cobalt oxide particle powder. Also good.

The Zr compound to be present on the particle surface has a chemical formula of Lix (Zr1-yAy) Oz (x, y and z are 2.0 ≦ x ≦ 8.0, 0 ≦ y ≦ 1.0, 2.0 ≦ z ≦ 6.0).
When x, y and z are out of the above ranges, it is difficult to say that the surface modification effect is sufficient. The Zr compound preferably has the chemical formula: Li ₂ ZrO ₃ (space group: C2 / c), Li ₆ Zr ₂ O ₇ , Li ₄ ZrO ₄ , Li ₈ ZrO ₆ . More preferably, it is Li ₂ ZrO ₃ in which x is 2.

  The Zr compound present on the particle surface may contain an element in which the A element is at least one selected from Mg, Al, Ca, Y, Ce, Sn, and Ti. By containing the element A, the cycle characteristics are further improved.

  The Zr content of the Zr compound in the lithium cobaltate particle powder coated with the Zr compound according to the present invention is 0.05 to 1.0 wt% with respect to the entire particle. When the Zr content is less than 0.05 wt%, the cycle characteristics are not improved. When the Zr content exceeds 1.0 wt%, the initial discharge capacity decreases. More preferably, it is 0.05-0.8 wt%.

  The average particle size of the primary particles of the Zr compound present on the particle surface is preferably 1.0 μm or less. When the average particle size of the Zr compound exceeds 1.0 μm, it is difficult to say that the surface modification effect is sufficient. More preferably, it is 0.1-0.8 micrometer.

The average particle diameter of the behavior particles of the lithium cobaltate particles coated with the Zr compound according to the present invention is preferably 1.0 to 30 μm . When the average particle size is less than 1 μm, the packing density is lowered and the safety is lowered. When it exceeds 30 μm, it is difficult to produce industrially. More preferably, the average particle size of the behavior particles is 2.0 to 25 μm, and even more preferably 10 to 20 μm.

In addition, the BET specific surface area of the lithium cobalt oxide particle powder coated with the Zr compound according to the present invention is preferably 1.0 m ² / g or less. When exceeding 1.0 m < ² > / g, since the fall with a packing density and the reactivity with electrolyte solution increase, it is unpreferable.

  Next, the manufacturing method of the lithium cobaltate particle powder coat | covered with the Zr compound based on this invention is described.

  The lithium cobalt oxide particle powder coated with the Zr compound according to the present invention is obtained by mixing and firing a cobalt raw material, a zirconium raw material, and a lithium raw material, and the cobalt raw material has an average particle size of behavior particles of 1 Cobalt oxide having a thickness of 0.0 μm or less (Invention 5).

  When the average particle diameter of the behavior particles of cobalt oxide exceeds 1.0 μm, the Zr compound is generated alone, and the surface modification effect of lithium cobaltate becomes insufficient. A more preferable average particle diameter is 0.1 to 0.5 μm.

  Note that cobalt oxide, which is a cobalt raw material, may contain at least one element selected from Ni, Mn, Si, Sn, Ti, Mg, and Al.

  Moreover, it is preferable that a zirconium raw material is a zirconium oxide whose average particle diameter of a behavior particle is 1.0 micrometer or less (this invention 6).

  When the average particle diameter of the behavior particles of zirconium oxide exceeds 1.0 μm, the Zr compound is generated alone, and the surface modification effect of lithium cobaltate becomes insufficient. A more preferable average particle diameter is 0.1 to 0.8 μm.

  When Lix (Zr1-yAy) Oz containing at least one element selected from Mg, Al, Ca, Y, Ce, Sn, Ti is present on the particle surface of the lithium cobalt oxide particle powder, What is necessary is just to add and mix the compound of said A element with a zirconium raw material.

  The mixing ratio of lithium is preferably 0.95 to 1.05 with respect to the total number of moles of metal elements (Co, Mg, different metals) in the cobalt oxide.

The firing temperature is preferably 600 ° C. to 1100 ° C. at which LiCoO ₂ that is a high-temperature ordered phase is generated. In the case of 600 ° C. The following LiCoO ₂ is produced a low-temperature phase having a pseudo-spinel structure, in the case of more than 1100 ° C. the location of the lithium and cobalt to produce the LiCoO ₂ hot disordered phase is random. The atmosphere during firing is preferably an oxidizing gas atmosphere. The reaction time is preferably 5 to 20 hours.

  Next, the positive electrode using the positive electrode active material which consists of lithium cobaltate particle powder coat | covered with the Zr compound for nonaqueous electrolyte secondary batteries which concerns on this invention is described.

  When a positive electrode is produced using the positive electrode active material according to the present invention, a conductive agent and a binder are added and mixed according to a conventional method. As the conductive agent, acetylene black, carbon black, graphite and the like are preferable, and as the binder, polytetrafluoroethylene, polyvinylidene fluoride and the like are preferable.

  The secondary battery manufactured using the positive electrode active material according to the present invention includes the positive electrode, the negative electrode, and an electrolyte.

  As the negative electrode active material, lithium metal, lithium / aluminum alloy, lithium / tin alloy, graphite, graphite, or the like can be used.

  In addition to the combination of ethylene carbonate and diethyl carbonate, an organic solvent containing at least one of carbonates such as propylene carbonate and dimethyl carbonate and ethers such as dimethoxyethane can be used as the solvent for the electrolytic solution.

  Further, as the electrolyte, in addition to lithium hexafluorophosphate, at least one lithium salt such as lithium perchlorate and lithium tetrafluoroborate can be dissolved in the above solvent and used.

  The secondary battery manufactured using the positive electrode active material according to the present invention has an initial discharge capacity of 150 to 170 mAh / g, a high load capacity maintenance rate measured by an evaluation method described later of 95% or more, and thermal stability ( The exothermic starting temperature) exhibits excellent characteristics of 180 ° C. or higher and a cycle capacity retention rate of 85% or higher.

<Action>
The important point in the present invention is that the lithium cobaltate particle powder was used as the positive electrode active material of the secondary battery by making the Zr compound composed of Lix (Zr1-yAy) Oz present on the particle surface of the lithium cobaltate particle. In some cases, this is the fact that a secondary battery having excellent load characteristics, cycle characteristics and thermal stability can be obtained.

  The reason why the lithium cobaltate particle powder coated with the Zr compound according to the present invention has excellent characteristics as the positive electrode active material of the secondary battery is that the Zr compound is present on the particle surface of the lithium cobaltate particle powder. The present inventor presumes that the surface activity can be suppressed without impairing the electrochemical properties of lithium cobalt oxide.

  A typical embodiment of the present invention is as follows.

The average particle size of the behavior particles was shown as a volume-based average particle size (D50) measured by a wet laser method using a laser type particle size distribution measuring device Microtrac HRA [manufactured by JGC Co., Ltd.].
In addition, it measured after adding sodium hexametaphosphate to a sample and carrying out ultrasonic dispersion | distribution.

  The average primary particle size was read from the SEM image.

  The presence state of the particles to be coated or present was observed using a scanning electron microscope SEM-EDX with an energy dispersive X-ray analyzer [manufactured by Hitachi High-Technologies Corporation].

  The average primary particle diameter of the particles to be coated or present was observed and confirmed using a scanning electron microscope SEM-EDX with an energy dispersive X-ray analyzer [manufactured by Hitachi High-Technologies Corporation].

  For identification of the sample, powder X-ray diffraction (RIGAKU Cu-Kα 40 kV 40 mA) was used.

  The specific surface area was measured by BET method using Macsorb HM model-1208 (manufactured by Mountec).

  The battery characteristics of the positive electrode active material were evaluated by preparing a coin-type battery cell by adjusting the positive electrode, the negative electrode, and the electrolytic solution by the following production method.

<Preparation of positive electrode>
93% by weight of Li—Co composite oxide as a positive electrode active material, 2% by weight of acetylene black as a conductive material and 2% by weight of graphite KS-16, 3% by weight of polyvinylidene fluoride dissolved in N-methylpyrrolidone as a binder, Were mixed, then applied to an Al metal foil and dried at 150 ° C. This sheet was punched out to 16 mm and then pressed at 1 t / cm ² to obtain a positive electrode plate having an electrode thickness of 50 μm.

<Production of negative electrode>
A metal lithium foil was punched into a disk shape of φ16 mm to produce a negative electrode.

<Adjustment of electrolyte>
As the electrolytic solution, a solution in which EC and DEC in which 1 mol / l LiPF ₆ was dissolved was mixed at a volume ratio of 3: 7 was used.

<Assembly of coin-type battery cells>
Using a case made of SUS316 in a glove box in an argon atmosphere, a CR2032-type coin battery was manufactured by injecting an electrolyte solution through a polypropylene separator between the positive electrode and the negative electrode.

<Battery evaluation>
The initial charge / discharge characteristics are as follows: at room temperature, charging is performed at a current density of 0.1 C up to 4.3 V, then low voltage charging is performed for 90 minutes, and discharging is performed at a current density of 0.1 C up to 3.0 V; The initial charge capacity, initial discharge capacity, and initial efficiency at that time were measured.

  For high load characteristics, after measuring discharge capacity (a) at 0.1 C, charge again at 0.1 C, then measure discharge capacity at 1.0 C (b), and b / a × 100 ( %).

  Regarding the cycle capacity retention rate, charge / discharge was repeated at a rate of 1.0 C when the cut-off voltage was between 3.0 V and 4.3 V, and the ratio of the discharge capacity at the 30th cycle to the initial discharge capacity was used.

<Thermal stability evaluation>
Using the coin-type battery, the battery is charged to a voltage of 4.5 V, the positive electrode active material in the battery is taken out and sealed in a thermal analysis container, and a differential thermal analyzer (at a heating rate of 10 ° C./min) DSC measurement was performed using DSC, DSC6200 manufactured by Seiko Instruments Inc. From the measurement results, the heat generation start temperature was regarded as thermal stability. The operation temperature was 300 to 400 ° C., and all the operations up to filling the above-described container were performed in a glove box having a dew point of −60 ° C. or less.

Example 1
A lithium cobalt oxide having an Mg content of 1.0 mol%, an Al content of 0.3 mol%, and a Zr content of 0.2 mol% was prepared. The lithium cobaltate was produced by the following production method.
That is, magnesium sulfate was added to a solution containing 0.5 mol / l of cobalt, and 1.05 equivalent of an aqueous sodium hydroxide solution was added to the neutralized component of cobalt and magnesium for neutralization reaction. Next, an oxidation reaction was performed at 90 ° C. for 20 hours while blowing air to obtain magnesium-containing cobalt oxide particle powder.
In the obtained cobalt oxide particle powder, the average particle size of the behavior particles was 0.2 μm.
The resulting cobalt oxide particles, the oxide zirconium arm and lithium carbonate were mixed and subjected to 10 hours calcined in an air atmosphere 1000 ° C..

The obtained lithium cobaltate particles had a composition of LiCo _0.987 Mg _0.01 Al _0.003 O ₂ , an average particle size of 15.0 μm, and a BET specific surface area of 0.22 m ² / g. . As a result of X-ray diffraction, it was confirmed that there was no heterogeneous phase and it was a lithium cobaltate single phase.
The SEM image (a) of the obtained lithium cobaltate particle powder and the Zr-mapped photograph (b) are shown in FIG. 1, and the SEM image (a) of the fracture surface of the lithium cobaltate particle powder and the Zr-mapped photograph ( b) is shown in FIG. The Zr-mapped photograph (b) is a color-coded (green) portion of the SEM image (a) in which Zr is detected by EDX. In FIG. 1B, a portion where Zr is detected and Zr is present (green portion) is circled. In FIG. 2B, Zr was not detected.
From FIG. 1 and FIG. 2, it was confirmed that the cobalt oxide particle powder obtained in Example 1 did not contain Zr inside the particle and Zr compound existed on the particle surface.

FIG. 3 shows an electron diffraction image of the Zr part of the lithium cobalt oxide particle powder obtained in Example 1. From the calculation result of the electron diffraction pattern analysis program (EDA), it was confirmed that the Zr compound was Li ₂ ZrO ₃ .

  The coin-type battery produced using the positive electrode active material had an initial discharge capacity of 158 mAh / g and a thermal stability of 183 ° C. Further, the high load capacity retention rate was 97%, and the cycle capacity retention rate was 92%.

Examples 2-6, Comparative Examples 1-4
Cathode active material comprising lithium cobalt oxide in the same manner as in Example 1 except that the average particle diameter of the behavior particles of cobalt oxide and zirconium oxide, the content of Zr, the kind of different metal, and the addition amount were variously changed. Got.

  Table 1 shows the production conditions at this time and various characteristics of the obtained positive electrode active material.

Regarding the lithium cobaltate particles obtained in Examples 2 to 6, the presence state and crystal structure of the Zr compound were confirmed in the same manner as in Example 1. As a result, Zr was not present inside the particles, and Li on the particle surface. ₂ ZrO ₃ was confirmed to be present.

The SEM image (a) of the lithium cobaltate particles obtained in Comparative Example 2 and the Zr-mapped photograph (b) are shown in FIG. 4, and the SEM image (a) of the lithium cobaltate particles obtained in Comparative Example 3 and A Zr-mapped photograph (b) is shown in FIG. In the photographs of FIGS. 4 and 5B, the portion surrounded by ◯ is the portion where Zr exists. 4 and 5, it was confirmed that the lithium cobalt oxide particle powder obtained in Comparative Examples 2 and 3 had a Zr compound on a part of the particle surface.
The SEM image (a) of the fracture surface of the lithium cobalt oxide particle powder obtained in Comparative Example 4 and the Zr-mapped photograph (b) are shown in FIG. 6, and the SEM image of the lithium cobalt oxide particle powder obtained in Comparative Example 4 ( FIG. 7 shows a) and a Zr-mapped photograph (b). A point where two straight lines in FIG. 6 intersect is a portion where Zr exists. In the photograph of FIG. 7B, the portion surrounded by ○ is the portion where Zr exists. 6 and 7, the cobalt oxide particle powder obtained in Comparative Example 4 was confirmed to contain Zr inside the particle and a Zr compound on a part of the particle surface.

Since the cobalt oxide particle powder according to the present invention is excellent in load characteristics, cycle characteristics and thermal stability, it is suitable as a positive electrode active material for a secondary battery.

It is the (a) SEM image and (b) Zr mapping figure of the lithium cobalt oxide particle powder obtained in Example 1. It is the (a) SEM image and (b) Zr mapping figure of the particle fracture surface of the lithium cobalt oxide particle powder obtained in Example 1. 2 is an electron diffraction pattern of a Zr part of the lithium cobalt oxide particle powder obtained in Example 1. FIG. It is the (a) SEM image and (b) Zr mapping figure of the lithium cobaltate particle powder obtained in the comparative example 2. It is the (a) SEM image and (b) Zr mapping figure of the lithium cobaltate particle powder obtained by the comparative example 3. It is the (a) SEM image and (b) Zr mapping figure of the fracture surface of the lithium cobalt oxide particle powder obtained by the comparative example 4. It is the (a) SEM image and (b) Zr mapping figure of the lithium cobaltate particle powder obtained by the comparative example 4. It is a graph which shows the relationship between Zr amount and a load characteristic. It is a graph which shows the relationship between Zr amount and thermal stability. It is a graph which shows the relationship between Zr amount and cycle characteristics. It is a graph which shows the discharge curve after 30 cycles of Example 1 and Comparative Example 4.

Claims (6)

A lithium cobaltate particle powder used as a positive electrode active material of a non-aqueous electrolyte secondary battery, wherein the lithium cobaltate particle powder is a lithium cobaltate particle powder coated with a Zr compound, and the Zr compound is contained inside the particle. The Zr compound is localized on the surface without being present, the chemical formula of the Zr compound is represented by Li ₂ ZrO ₃ , and the Zr content is 0.05 to 1.0 wt% with respect to the entire particle , Lithium cobaltate particles coated with a Zr compound, wherein the primary particles have an average particle size of 1.0 μm or less. In the method for producing lithium cobaltate particles coated with a Zr compound in which a cobalt raw material, a zirconium raw material, and a lithium raw material are mixed and fired, the average particle size of the behavior particles measured by the laser particle size distribution measuring device of the cobalt raw material is 1 claim 1 Symbol mounting method of manufacturing a coated lithium cobaltate particles in Zr compound of wherein the .0μm is less cobalt oxide. In the method for producing lithium cobaltate particles coated with a Zr compound in which a cobalt raw material, a zirconium raw material, and a lithium raw material are mixed and fired, the average particle size of the behavior particles measured by the laser particle size distribution measuring device of the cobalt raw material is 1 .0μm a less cobalt oxide, and, according to claim 2, wherein the average particle size of the zirconium starting material for a laser particle size distribution analyzer measured behavior particles is less zirconium oxide 1.0μm A method for producing lithium cobalt oxide particle powder coated with a Zr compound. The average particle diameter of the behavior particles measured by the laser particle size distribution measuring apparatus of the zirconium raw material is cobalt oxide whose average particle diameter of the behavior particles measured by the laser particle size distribution measuring apparatus of the cobalt raw material is 0.5 μm or less. The method for producing lithium cobaltate particle powder coated with a Zr compound according to claim 3 , wherein the zirconium oxide is 0.8 µm or less. The Zr compound according to any one of claims 2 to 4 , wherein the cobalt raw material is cobalt oxide containing at least one element selected from Ni, Mn, Si, Sn, Ti, Mg, and Al. A method for producing a coated lithium cobalt oxide particle powder. Non-aqueous electrolyte secondary battery using the claim 1 Symbol placement lithium cobaltate particles coated with Zr compound as a positive electrode active material or a portion thereof.