JP2013191579A - Cathode material for nonaqueous electrolyte lithium ion battery, battery using the same, and manufacturing method of cathode material for nonaqueous electrolyte lithium ion battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide secondary particles in which primary particles are not easily dissociated even when high output charge / discharge is performed.
SOLUTION: It comprises secondary particles composed of a lithium compound and lithium-transition metal oxide particles, the lithium compound does not contain a transition metal, and the number of moles of lithium in the secondary particle is that of the transition metal. A positive electrode material for a non-aqueous electrolyte lithium-ion battery, characterized by being larger than the number of moles.
[Selection] Figure 1

Description

The present invention relates to a positive electrode material for a non-aqueous electrolytic lithium ion battery, and more particularly to a positive electrode material for a non-aqueous electrolytic lithium ion battery with improved durability.

A non-aqueous electrolyte lithium ion battery has a structure in which a positive electrode and a negative electrode are inserted into a container and a liquid non-aqueous electrolyte is enclosed. A power source for information devices such as a mobile phone or an electric vehicle (EV)
It is used for hybrid vehicle (HEV) and fuel cell vehicle (FCV) motor drives, hybrid auxiliary power supplies, and the like.

Among these applications, non-aqueous electrolyte lithium ion batteries used for EV, HEV, and FCV are required to have higher output and longer cycle life.

As a means to increase the output and cycle life of the non-aqueous electrolyte lithium ion battery, secondary particles obtained by aggregating primary particles as shown in Patent Document 1 are used as a positive electrode material, and the internal resistance is lowered and the output is increased. There is a method of suppressing output deterioration due to resistance rise. In Patent Document 1, a primary particle-shaped oxide containing lithium and manganese is an aggregate in an electrostatically and / or mechanically aggregated state, and the aggregate is formed into individual primary particles by a physical external force. A positive electrode active material for a lithium secondary battery, which is a form to be separated, is disclosed.
Japanese Patent Laid-Open No. 2003-203632

However, since the positive electrode active material described in Patent Document 1 has a weak binding force between primary particles, there is a high possibility that primary particles will dissociate when high output charge / discharge is repeated. Dissociation between primary particles may cause an increase in resistance and a decrease in capacity inside the battery.

In order to solve the above-described problems, an object of the present invention is to provide secondary particles in which primary particles are not easily dissociated even when high-power charge / discharge is performed.

The present inventor is a secondary particle composed of a lithium compound and lithium-transition metal oxide particles. It was found that the lithium-transition metal particles which are primary particles are difficult to dissociate even when the above is repeated, and the present invention has been completed.

That is, the present invention comprises secondary particles composed of a lithium compound and lithium-transition metal oxide particles, the lithium compound does not contain a transition metal, and the number of moles of lithium in the secondary particles is transition metal. The above problem is solved by a positive electrode material for a non-aqueous electrolyte lithium ion battery characterized in that the number of moles is larger than the number of moles.

According to the present invention, it is possible to provide a non-aqueous electrolyte lithium ion battery in which a decrease in cycle life due to repeated high-power charge / discharge is suppressed.

The first of the present invention consists of secondary particles composed of a lithium compound and lithium-transition metal oxide particles, the lithium compound does not contain a transition metal, and the number of moles of lithium in the secondary particles is It is a positive electrode material for a non-aqueous electrolyte lithium ion battery characterized by having more than the number of moles of transition metal.

Secondary particles used for the positive electrode material are composed of lithium compounds and lithium-transition metal oxide particles (hereinafter also referred to as primary particles), and the number of moles of lithium in the secondary particles is determined from the number of moles of transition metal. By increasing the number of primary particles, primary particles are unlikely to dissociate even when high output charge / discharge is repeated. For this reason, the fall of the cycle life accompanying dissociation of primary particles can be suppressed.

Although the number of moles of lithium in the secondary particles may be larger than the number of moles of the transition metal, it is preferably 1.05 times or more, more preferably 1.07 times or more. It is preferable for the number of moles to be 1.05 times or more because the effect of making primary particles difficult to dissociate increases.

The reason why dissociation between primary particles can be suppressed according to the present invention is that the lithium compound serves as a binder by making the number of moles of lithium in the secondary particles larger than the number of moles of the transition metal. It is thought that it is to become. In addition, since lithium-transition metal oxide particles release and occlude lithium ions during charging and discharging, the size of the particles fluctuates during charging and discharging, and the particles easily dissociate. It is considered that one of the reasons is that the size does not change even during discharge.

In addition to the effect of suppressing dissociation of primary particles, the lithium compound also has an effect of suppressing deterioration of the electrolytic solution. The transition metal contained in the lithium-transition metal oxide particles is charged and discharged.
In some cases, oxygen ions contained in the electrolytic solution may be radicalized, and when oxygen radicals are generated, the electrolytic solution contained in the battery may be decomposed. However, by using a lithium compound that does not contain a transition metal in combination, contact between oxygen ions and the transition metal can be suppressed, so that generation of oxygen radicals can be suppressed.

The lithium compound may be disposed on the surface of the aggregate of lithium-transition metal oxide particles, may be disposed on the surface of the lithium-transition metal oxide particle, or a combination thereof.

1 and 2 show preferred examples in which a lithium compound is arranged on the surface of lithium-transition metal oxide particles.

As shown in FIG. 1, when the lithium compound 20 is in the form of a film and covers the surface of the lithium-transition metal oxide particles 10, the expansion of the battery that occurs when high-power charge / discharge is repeated is suppressed. This is preferable. This is considered to be because the surface of the lithium-transition metal oxide particles is coated with a lithium compound, and thus the lithium-transition metal oxide particles can effectively suppress the generation of oxygen radicals.

In this case, the film thickness of the lithium compound is preferably 3 to 1000 nm, more preferably 5 to 5 nm.
The thickness is 1000 nm, more preferably 5 to 700 nm, and particularly preferably 5 to 100 nm. When the film thickness of the lithium compound is less than 3 nm, the binding property between the primary particles may be reduced. Moreover, when the film thickness is less than 3 nm, the primary particles may oxidize oxygen ions to generate oxygen radicals. When the film thickness exceeds 1000 nm, it becomes difficult to conduct lithium ions, and the power generation characteristics of the battery may be deteriorated. The film thickness of the lithium compound can be measured by TEM observation of the cross section of the primary particles.

As shown in FIG. 2, it is preferable that the lithium compound 20 is in the form of particles and is scattered on the surface of the lithium-transition metal oxide particles 10 because an increase in the internal resistance of the battery can be suppressed. This is considered to be because some of the lithium-transition metal oxide particles are exposed.

In this case, the average particle size of the lithium compound is preferably 10 to 2000 nm, and more preferably 50 to 1500 nm. When the average particle size is less than 10 nm, the binding property between the primary particles may be reduced, and when it is more than 2000 nm, it becomes difficult to interspers the lithium compound particles, and the power generation characteristics may be deteriorated. is there.

Moreover, when a lithium compound is arrange | positioned as shown in FIG. 2, when the volume of lithium-transition metal oxide particle is 100, the volume of a lithium compound is preferably 0.5 to 250, more preferably 0.8. 7-150. If the volume is less than 0.5, the binding property between the primary particles may be reduced, and if it is more than 250, it is difficult to interspers the lithium compound particles, and the power generation characteristics may be reduced. is there.

The lithium compound is not particularly limited as long as it does not contain a transition metal, and a conventionally known one can be used. However, as shown in FIG. When the surface of the metal oxide particles is coated, it is necessary to have lithium ion conductivity. In addition, as shown in FIG. 2, the lithium compound preferably has lithium ion conductivity even in the case where a part of the lithium-transition metal oxide particles is exposed, and has lithium ion conductivity. By using a lithium compound, an increase in the internal resistance of the battery can be suppressed.

Examples of the lithium-ion conductivity of the lithium compound ^is preferably ¹⁰ -15 S · ^{m -1} or more, more preferably ¹⁰ -12 S · ^{m -1.} Lithium ion conductivity is ^10-15 S
^-The rise of the internal resistance of a battery can be effectively suppressed as it is more than m- ¹ . The lithium ion conductivity can be measured by an AC impedance method, a constant potential step method, a constant current step method, and the like.

Examples of the lithium compound having lithium ion conductivity include lithium sulfate, lithium phosphate, LiPON compound, Li ₂ O—B ₂ O ₃ compound, Li ₂ O—B ₂ O ₃ —LiI compound, Li ₂ S—SiS _{2. compound, Li 2 S-SiS 2 -Li} 3 PO 4 compounds, lithium fluoride, lithium acetate, lithium acetylide ethylenediamine, lithium benzoate, lithium bromide, lithium carbonate, lithium nitrate, lithium oxalate, lithium pyruvate, stearate Preferably, at least one selected from the group consisting of lithium, lithium tartrate, lithium hydroxide, and lithium sulfur phosphate compound, more preferably lithium sulfate, lithium phosphate, Li ₂ O—B ₂ O ₃ compound, acetic acid Lithium, lithium acetylide amine, lithium benzoate Beam, lithium bromide, lithium carbonate, and lithium pyruvate.

Examples of the transition metal contained in the lithium-transition metal oxide particles include Sc, Ti, V, Cr,
Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Pd, Ag
, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm,
It is preferable to include at least one selected from Yb, Lu, Hf, Ta, W, Re, Os, Ir, Pt, and Au, more preferably at least one selected from the group consisting of Ni, Mn, and Co. Including seeds.

As the lithium-transition metal oxide containing at least one selected from the group consisting of Ni, Mn and Co as a transition metal, a compound represented by the following chemical formula 1 is preferably exemplified.

In Chemical Formula 1, 0 <a ≦ 1.2, 0 ≦ b ≦ 0.85, 0 ≦ c ≦ 0.4, 0 ≦ d ≦ 0
. 6, 0 ≦ e ≦ 0.1, 0.9 ≦ b + c + d + e ≦ 1, −0.05 ≦ x ≦ 0.1, 0 ≦ y
≦ 0.05, M is at least one selected from the group consisting of Al, Mg, Ca, Ti, V, Cr, Fe, and Ga, and N is selected from the group consisting of F, Cl, and S At least one kind.

The average particle size of the lithium-transition metal oxide particles is preferably 0.01-2 μm, more preferably 0.015-1.5 μm. If the average particle size is less than 0.01 μm, the resistance may increase, and if it exceeds 2 μm, the cycle durability may decrease. The average particle size of the lithium-transition metal oxide particles can be measured by observation using SEM or TEM.

In addition to the secondary particles described above, the positive electrode material of the present invention includes V ₂ O ₅ , MnO ₂ , TiS ₂ , Mo
A positive electrode material active material such as S ₂ , MoO ₃ , PbO ₂ , AgO, and NiOOH, a conductive assistant, a binder, a polymer electrolyte such as a host polymer or an electrolyte, and a lithium salt may be included.

  A conventionally well-known technique can be used suitably for the kind, ratio, etc. of the component of positive electrode material.

  The second of the present invention is the above-described method for producing a positive electrode material for a non-aqueous electrolyte lithium ion battery.

As a method for producing a positive electrode material for a non-aqueous electrolyte lithium ion battery according to the present invention, as shown in FIG. 1, the lithium compound 20 is in the form of a film and covers the surface of the lithium-transition metal oxide particles 10. When producing secondary particles, a wet method is effective, and the lithium compound 20 is in the form of particles as shown in FIG. 2 and is scattered on the surface of the lithium-transition metal oxide particles 10. When producing secondary particles, the dry method is effective.

As a wet method, a step of preparing a mixed solution by mixing a lithium compound, an inorganic salt containing lithium ions, an inorganic salt containing transition metal ions, and a solvent, a step of drying the mixed solution to obtain a precursor, and Heat treating the precursor to produce secondary particles comprising lithium compounds and lithium-transition metal oxide particles, wherein the number of moles of lithium contained in the inorganic salt containing the lithium compound and the lithium ions is the transition. A production method for increasing the number of moles of transition metals contained in the inorganic salt containing metal ions is preferred.

As a dry method, an inorganic salt containing lithium ions, an inorganic salt containing transition metal ions, and a solvent are mixed to prepare a mixed solution, the mixed solution is dried to obtain a precursor, and the precursor is heat treated. A step of obtaining lithium-transition metal oxide particles, and a step of producing secondary particles comprising a lithium compound and the lithium-transition metal oxide particles comprising a dry mixed lithium compound and lithium-transition metal oxide particles. A method for producing a positive electrode material, wherein the number of moles of lithium contained in the lithium compound and the inorganic salt containing lithium ions is greater than the number of moles of the transition metal contained in the inorganic salt containing transition metal ions. Is preferred.

In the wet method or the dry method described above, the solvent is preferably water. The stirring time of the mixed solution is preferably 4 to 24 hours, and the stirring method is preferably a stirring method using a propeller stirrer. Dry the mixture with stirring. The drying time is preferably 4 to 24 hours, and the drying temperature is 6
0-120 degreeC is preferable. The heat treatment time of the precursor is preferably 4 to 24 hours, and the heat treatment temperature is preferably 300 to 500 ° C.

Secondary particles composed of a lithium compound and lithium-transition metal oxide particles can be produced by the above-described wet method or dry method. The secondary particles can be preferably used as a positive electrode material for a non-aqueous electrolyte lithium ion battery.

By making the number of moles of lithium contained in the inorganic salt containing lithium compound and lithium ions greater than the number of moles of transition metal contained in the inorganic salt containing transition metal ions, lithium in the produced secondary particles The number of moles can be greater than the number of moles of transition metal. As described above, the secondary particles used in the positive electrode material are composed of lithium compounds and lithium-transition metal oxide particles, and the number of moles of lithium in the secondary particles is larger than the number of moles of transition metal. Thus, even when high-power charge / discharge is repeated, the primary particles are difficult to dissociate. For this reason, the fall of the cycle life accompanying dissociation of primary particles can be suppressed.

The number of moles of lithium contained in the inorganic salt containing the lithium compound and lithium ions may be larger than the number of moles of the transition metal contained in the inorganic salt containing the transition metal ion, preferably 1.05 times or more, More preferably, it is 1.075 times or more. It is preferable that the number of moles is 1.05 times or more because primary particles are unlikely to dissociate.

After the secondary particles are produced by the wet method or the dry method described above, it is preferable to wash the obtained secondary particles because the specific surface area of the secondary particles increases. This is because the lithium compound that is not involved in the binding between the primary particles is removed from the secondary particles by washing,
This is because the voids of the secondary particles become large. As a washing method, it is preferable to mix the produced secondary particles and pure water so as to have a mass ratio of 1: 5, stir the mixture with a propeller stirrer for 1 to 4 hours, and stir and then filter. The washing is preferably repeated 2 to 5 times. After filtration, the secondary particles are preferably dried at 150 to 250 ° C. for 5 to 15 hours.

Examples of the inorganic salt containing a transition metal used in the above production method include hydroxide, acetic acid compound, sulfuric acid compound, nitric acid compound, chloride, fluoride, iodide, bromide, oxalic acid compound, phosphoric acid compound, Li ₂ Selected from the group consisting of O—B ₂ O ₃ compound, Li ₂ O—B ₂ O ₃ —LiPO ₄ compound, lithium acetylide amine, lithium benzoate, lithium carbonate, lithium pyruvate, lithium stearate, and lithium tartrate At least one is preferred.

The hydroxide is nickel hydroxide, manganese hydroxide, or cobalt hydroxide, the acetic acid compound is nickel acetate, manganese acetate, or cobalt acetate, and the sulfate compound is nickel sulfate, manganese sulfate, or cobalt sulfate. The nitrate compound is nickel nitrate, manganese nitrate, or cobalt nitrate; the chloride is nickel chloride, manganese chloride, or cobalt chloride; and the fluoride is nickel fluoride, manganese fluoride, or cobalt fluoride. The iodide is nickel iodide, manganese iodide, or cobalt iodide; the bromide is nickel bromide, manganese bromide, or cobalt bromide; and the oxalic acid compound is nickel oxalate, Manganese acid or cobalt oxalate, the phosphoric acid compound Nickel phosphate is preferably manganese phosphate or cobalt phosphate.

The lithium compound or the inorganic salt containing lithium ions is lithium sulfate, lithium phosphate, LiPON compound, Li ₂ O—B ₂ O ₃ compound, Li ₂ O—B ₂ O ₃ —LiI compound, Li ₂ S—SiS _{2. compound, Li 2 S-SiS 2 -Li} 3 PO 4 compounds, lithium fluoride, lithium acetate, lithium acetylide ethylenediamine, lithium benzoate, lithium bromide, lithium carbonate, lithium nitrate, lithium oxalate, lithium pyruvate, stearate Preferably, the lithium compound is at least one selected from the group consisting of lithium, lithium tartrate, lithium hydroxide, and lithium sulfur phosphate compound. Examples of the lithium compound include lithium sulfate, lithium phosphate, Li ₂ O—B ₂ O. ₃ compounds, lithium acetate, lithium acetate Chile Amines, lithium benzoate, lithium bromide, lithium carbonate, and lithium pyruvate is more preferred, and more preferably lithium hydroxide as an inorganic salt containing lithium ions.

The preferable film thickness, particle size, lithium ion conductivity, volume ratio between the lithium compound and the lithium-transition metal oxide particles, the preferable primary particle size, and the like are as described above.

A third aspect of the present invention is a nonaqueous electrolyte lithium ion battery including the above-described positive electrode material or the positive electrode material produced by the above-described method.

The positive electrode material included in the nonaqueous electrolyte lithium ion battery of the present invention is excellent in durability because primary particles are unlikely to dissociate even when high-power charge / discharge is performed.

A conventionally well-known technique can be used suitably about components, such as a collector included in the nonaqueous electrolyte lithium ion battery of this invention, a negative electrode active material, and a nonaqueous electrolyte.

The battery of the present invention can be connected in parallel-series, series-parallel, series, or parallel to form an assembled battery. The assembled batteries may be connected in series and / or in parallel to form a composite assembled battery. Each of the composite assembled batteries may be detachable. The assembled battery or the composite assembled battery can be mounted on a vehicle.

EXAMPLES Next, although an Example is given and this invention is demonstrated concretely, these Examples do not restrict | limit this invention at all.

Example 1
[Production of positive electrode]
Lithium hydroxide, nickel hydroxide, cobalt hydroxide, aluminum hydroxide in molar ratio,
Li: Ni: Co: Al = 10: 0.8: 0.15: 0.05 was added to water so that
Furthermore, lithium sulfate was added so that the molar ratio of lithium contained with respect to the lithium hydroxide was 10: 0.5 to prepare a mixed solution. The mixture was heated to 200 ° C. with stirring to evaporate water. After evaporating 95% or more of water, it was transferred to a ceramic crucible, heated to 400 ° C. at 100 ° C./h in air, and pre-fired at 400 ° C. for 12 hours. After calcination, 8
00 ° C. Firing was carried out in an oxygen atmosphere for 24 hours, and after firing, the mixture was allowed to stand at room temperature while flowing oxygen to obtain secondary particles as a positive electrode material for a non-aqueous electrolyte lithium ion battery.

Next, the positive electrode material and water were mixed at a mass ratio of 1: 5, and the mixture was stirred for 2 hours with a propeller stirrer and then filtered. This was repeated three times and then vacuum dried at 200 ° C. for 12 hours.

As shown in FIG. 1, the shape of the obtained positive electrode material is L-transition metal oxide particles L
i _1.00 Ni _0.82 Co _0.15 Al _0.03 O _2.00 The particle surface is covered with lithium sulfate as a lithium compound, and Li _1.00 Ni _0.82 Co _{0. 1}
The average particle diameter of ₅ Al _0.03 O _2.00 particles was 500 nm, and the film thickness of lithium sulfate was 50 nm.

75% by mass of the positive electrode material described above, 10% by mass of acetylene black as a conductive additive, 15% by mass of polyvinylidene fluoride as a binder, N-methyl-2-pyrrolidone as a solvent (
NMP) and stirred to prepare a positive electrode active material slurry. The positive electrode active material slurry was applied on an aluminum foil (thickness 20 μm) as a positive electrode current collector with an applicator, dried by heating at 80 ° C. with a vacuum dryer, and then punched out to a diameter of 15 mm, 10 ⁻¹ Pa Under high vacuum conditions,
Dry at 90 ° C. for 6 hours. The thickness of the punched positive electrode was 50 μm.

[Production of negative electrode]
85% by mass of carbon as a negative electrode active material, 8% by mass of acetylene black as a conductive additive, 2% by mass of vapor grown carbon fiber (VGCF), 5% by mass of polyvinylidene fluoride as a binder, and NMP as a solvent In addition, the mixture was stirred to prepare a negative electrode active material slurry. The negative electrode active material slurry was coated on a copper foil (thickness 20 μm) as a negative electrode current collector with an applicator, dried by heating at 80 ° C. with a vacuum dryer, and then punched to a diameter of 16 mm.
^The film was dried at 90 ° C. for 6 hours under a high vacuum condition of ⁻¹ Pa. The thickness of the punched negative electrode is 80
It was μm.

[Production of battery]
Microporous separator (average pore diameter = 800 nm, porosity = 35%, thickness = 30 μm) composed of the above positive electrode, the above negative electrode, polyvinylidene fluoride, non-aqueous electrolyte (0.1 M LiPF ₆₎ A coin cell was prepared using an ethylene carbonate-diethyl carbonate solution containing benzene, an ethylene carbonate: diethyl carbonate mass ratio of 2: 8), and an exterior (SUS). A durability test was performed using the produced coin cell.

[Durability test]
Immediately after the above coin cell was fabricated, it was charged to 4.1 V at 0.2 C in terms of positive electrode and stored at room temperature for 1 hour. Thereafter, the internal resistance of the battery was determined by direct current at 25 ° C., and charging and discharging at 4.1 V to 2.5 V and a constant current of 1 C were performed 200 cycles at 45 ° C.

The rate of increase in internal resistance of the battery was defined as shown in Equation 1 below. Table 1 shows the measurement results of the durability test.

(Example 2)
A battery was produced in the same manner as in Example 1 except that lithium phosphate was used instead of lithium sulfate in the production of the positive electrode material, and a durability test was performed.

(Example 3)
A battery was produced in the same manner as in Example 1 except that Li _2.9 PO _3.3 N _0.36 was used instead of lithium sulfate in the production of the positive electrode material, and the durability test was performed.

Example 4
A battery was produced in the same manner as in Example 1 except that a Li ₂ O—B ₂ O ₃ compound was used instead of lithium sulfate in the production of the positive electrode material, and a durability test was performed.

(Example 5)
A battery was produced in the same manner as in Example 1 except that a Li ₂ O—B ₂ O ₃ —LiI compound was used instead of lithium sulfate in the production of the positive electrode material, and a durability test was performed.

(Example 6)
A battery was prepared in the same manner as in Example 1 except that a Li ₂ S—SiS ₂ compound was used instead of lithium sulfate in the production of the positive electrode material, and a durability test was performed.

(Example 7)
In the production of the positive electrode material, Li ₂ S—SiS ₂ —Li ₃ PO ₄ instead of lithium sulfate.
A battery was prepared in the same manner as in Example 1 except that the compound was used, and a durability test was performed.

(Example 8)
A battery was produced in the same manner as in Example 1 except that lithium fluoride was used instead of lithium sulfate in the production of the positive electrode material, and a durability test was performed.

Example 9
A battery was produced in the same manner as in Example 1 except that lithium acetate was used instead of lithium sulfate in the production of the positive electrode material, and a durability test was performed.

(Example 10)
A battery was produced in the same manner as in Example 1 except that lithium acetylide ethylenediamine was used instead of lithium sulfate in the production of the positive electrode material, and a durability test was performed.

(Example 11)
A battery was produced in the same manner as in Example 1 except that lithium benzoate was used instead of lithium sulfate in the production of the positive electrode material, and a durability test was performed.

(Example 12)
A battery was produced in the same manner as in Example 1 except that lithium bromide was used instead of lithium sulfate in the production of the positive electrode material, and a durability test was performed.

(Example 13)
A battery was produced in the same manner as in Example 1 except that lithium carbonate was used instead of lithium sulfate in the production of the positive electrode material, and a durability test was performed.

(Example 14)
In the production of the positive electrode material, a battery was produced in the same manner as in Example 1 except that lithium nitrate was used instead of lithium sulfate, and a durability test was performed.

(Example 15)
A battery was produced in the same manner as in Example 1 except that lithium oxalate was used instead of lithium sulfate in the production of the positive electrode material, and a durability test was performed.

(Example 16)
A battery was produced in the same manner as in Example 1 except that lithium pyruvate was used instead of lithium sulfate in the production of the positive electrode material, and a durability test was performed.

(Example 17)
A battery was produced in the same manner as in Example 1 except that lithium stearate was used instead of lithium sulfate in the production of the positive electrode material, and a durability test was performed.

(Example 18)
A battery was produced in the same manner as in Example 1 except that lithium tartrate was used instead of lithium sulfate in the production of the positive electrode material, and a durability test was performed.

(Example 19)
A battery was produced in the same manner as in Example 1 except that lithium hydroxide was used instead of lithium sulfate in the production of the positive electrode material, and a durability test was performed.

(Example 20)
A battery was produced in the same manner as in Example 1 except that a lithium lithium phosphate compound was used instead of lithium sulfate in the production of the positive electrode material, and a durability test was performed.

(Comparative Example 1)
A battery was prepared in the same manner as in Example 1 except that secondary particles composed of lithium-transition metal oxide particles were used instead of secondary particles composed of lithium compounds and lithium-transition metal oxide particles. A sex test was performed.

The secondary particles are added to water so that lithium carbonate, nickel carbonate, cobalt carbonate, and aluminum carbonate are in a molar ratio of Li: Ni: Co: Al = 1: 0.8: 0.15: 0.05. Thus, a mixed solution was prepared and fired at 800 ° C. in an oxygen atmosphere for 24 hours.

(Comparative Example 2)
A battery was prepared in the same manner as in Example 1 except that secondary particles composed of lithium-transition metal oxide particles were used instead of secondary particles composed of lithium compounds and lithium-transition metal oxide particles. A sex test was performed.

The secondary particles are added to water so that lithium carbonate, nickel carbonate, cobalt carbonate, and aluminum carbonate are in a molar ratio of Li: Ni: Co: Al = 1: 0.8: 0.15: 0.05. Then, a mixed solution was prepared, baked in an oxygen atmosphere at 800 ° C. for 24 hours, and the obtained particles were prepared by dry pulverization using a jet mill manufactured by Hosokawa Micron.

(Comparative Example 3)
A battery was prepared in the same manner as in Example 1 except that secondary particles composed of lithium-transition metal oxide particles were used instead of secondary particles composed of lithium compounds and lithium-transition metal oxide particles. A sex test was performed.

A method for producing lithium-transition metal oxide particles will be described below. Lithium hydroxide, nickel hydroxide, cobalt hydroxide, aluminum hydroxide in molar ratio, Li: Ni: Co: Al = 30
: 0.8: 0.15: 0.05 was added to water to prepare a mixed solution, and the mixed solution was heated to 200 ° C. while stirring to evaporate water. After evaporating 95% or more of water, it was transferred to a ceramic crucible, heated to 400 ° C. at 100 ° C./h in air, and pre-fired at 400 ° C. for 12 hours. After calcination, 800 ° C. Firing was carried out in an oxygen atmosphere for 24 hours, and after firing, the mixture was allowed to stand at room temperature while flowing oxygen to obtain secondary particles as a positive electrode material for a non-aqueous electrolyte lithium ion battery.

This is a preferred example in which a lithium compound is arranged on the surface of lithium-transition metal oxide particles. This is a preferred example in which a lithium compound is arranged on the surface of lithium-transition metal oxide particles.

10 lithium-transition metal oxide particles,
20 Lithium compound.

Claims (13)

Consisting of secondary particles composed of lithium compounds and lithium-transition metal oxide particles,
The lithium compound does not contain a transition metal,
The lithium compound covers the surface of primary particles of the lithium-transition metal oxide particles;
The positive electrode material for a non-aqueous electrolyte lithium ion battery, wherein the number of moles of lithium in the secondary particles is larger than the number of moles of transition metal. 2. The positive electrode material according to claim 1, wherein lithium ion conductivity of the lithium compound is 10 ⁻¹⁵ S · m ⁻¹ or more.   The positive electrode material according to claim 1 or 2, wherein the transition metal includes at least one selected from the group consisting of Ni, Mn, and Co. The positive electrode material according to claim 3, wherein the lithium-transition metal oxide is a compound represented by the following chemical formula 1.
In Chemical Formula 1, 0 <a ≦ 1.2, 0 ≦ b ≦ 0.85, 0 ≦ c ≦ 0.4, 0 ≦ d ≦ 0.6, 0 ≦ e ≦ 0.1, 0.9 ≦ b + c + d + e ≦ 1, −0.05 ≦ x ≦ 0.1, 0 ≦ y ≦ 0.05, M is at least one selected from the group consisting of Al, Mg, Ca, Ti, V, Cr, Fe, and Ga N is at least one selected from the group consisting of F, Cl, and S. The lithium compound is lithium sulfate, lithium phosphate, LiPON compound, Li ₂ O—B ₂ O ₃ compound, Li ₂ O—B ₂ O ₃ —LiI compound, Li ₂ S—SiS ₂ compound, Li ₂ S—SiS _2. -Li ₃ PO ₄ compounds, lithium fluoride, lithium acetate, lithium acetylide ethylenediamine, lithium benzoate, lithium bromide, lithium carbonate, lithium nitrate, lithium oxalate, lithium pyruvate, lithium stearate, lithium tartrate, lithium hydroxide And at least one selected from the group consisting of lithium phosphate lithium compounds. 5. The positive electrode material according to claim 1,   The positive electrode material according to claim 1, wherein the lithium compound is in a film form, and the thickness of the lithium compound is 5 to 100 nm.   The positive electrode material according to claim 1, wherein the lithium-transition metal oxide particles have an average particle diameter of 0.01 to 2 μm. Mixing a lithium compound, an inorganic salt containing lithium ions, an inorganic salt containing transition metal ions, and a solvent to prepare a mixed solution;
Drying the mixture to obtain a precursor;
Heat treating the precursor to produce secondary particles composed of lithium compounds and lithium-transition metal oxide particles,
The lithium compound coats the surface of the lithium-transition metal oxide particles;
The number of moles of lithium contained in the lithium salt containing the lithium compound and the lithium ion is greater than the number of moles of transition metal contained in the inorganic salt containing the transition metal ion. Manufacturing method of positive electrode material.   The number of moles of lithium contained in the lithium salt containing the lithium compound and the lithium ion is 1.05 times or more of the number of moles of transition metal contained in the inorganic salt containing the transition metal ion. The manufacturing method according to claim 8.   The manufacturing method according to claim 8, further comprising a step of cleaning the secondary particles.   The inorganic salt containing the transition metal ion is at least selected from the group consisting of hydroxides, acetic acid compounds, sulfuric acid compounds, nitric acid compounds, chlorides, fluorides, iodides, bromides, oxalic acid compounds, and phosphorylated compounds. It is a 1 type, The manufacturing method of any one of Claims 8-10 characterized by the above-mentioned. The lithium compound or the inorganic salt containing the lithium ion is lithium sulfate, lithium phosphate, LiPON compound, Li ₂ O—B ₂ O ₃ compound, Li ₂ O—B ₂ O ₃ —LiI compound, Li ₂ S—SiS _{2. compound, Li 2 S-SiS 2 -Li} 3 PO 4 compounds, lithium fluoride, lithium acetate, lithium acetylide ethylenediamine, lithium benzoate, lithium bromide, lithium carbonate, lithium nitrate, lithium oxalate, lithium pyruvate, stearate The production method according to any one of claims 8 to 11, wherein the production method is at least one selected from the group consisting of lithium, lithium tartrate, lithium hydroxide, and a lithium lithium phosphate compound.   A non-aqueous electrolyte lithium ion battery comprising the positive electrode material according to any one of claims 1 to 7 or the positive electrode material produced by the method according to any one of claims 8 to 12.