JP2010092706A - Positive electrode material for nonaqueous electrolyte secondary battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positive electrode material for a nonaqueous electrolyte secondary battery enhancing reliability and safety of the battery by suppressing the generation of gas on the interface between an electrolyte and a positive electrode and elution of ions without using a metal oxide or a metal fluoride as a positive electrode active material, and to provide a method for manufacturing the same and the nonaqueous electrolyte secondary battery. <P>SOLUTION: The positive electrode material for the nonaqueous electrolyte secondary battery contains a lithium atom and an atom selected from the group consisting of a nickel atom, a cobalt atom, a manganese atom, an aluminum atom and a magnesium atom, and contains composite oxide particles having space group R-3m structure or Fd3m structure, and a phosphonate compound represented by formula (I) (in the formula (I), R<SP>1</SP>, R<SP>2</SP>, R<SP>3</SP>are each independently alkyl group, aryl group, aralkyl group, a group represented by formula:-R<SP>4</SP>-C(O)-O-R<SP>5</SP>(R<SP>4</SP>is alkylene group, R<SP>5</SP>is alkyl group), vinyl group, vinyl alkyl group, vinyl aryl group, or vinyl aryl alkyl group). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a positive electrode material for a non-aqueous electrolyte secondary battery. More specifically, a positive electrode material for a non-aqueous electrolyte secondary battery capable of suppressing gas generation from the positive electrode and elution of metal ions during a charging operation of the non-aqueous electrolyte secondary battery, a method for producing the same, and the non-aqueous electrolyte The present invention relates to a non-aqueous electrolyte secondary battery containing a positive electrode material for a secondary battery.

  In recent years, non-aqueous electrolyte secondary batteries have been in the spotlight because of their high energy density compared to conventional water-based secondary batteries such as nickel-cadmium batteries.

  The increase in capacity and energy density of non-aqueous electrolyte secondary batteries is achieved by increasing the storage mass of lithium per unit volume or volume of the positive electrode active material used in non-aqueous electrolyte secondary batteries and increasing the charging potential. This is done by increasing the amount of lithium absorbed and released as a charge carrier.

  However, when the charge potential of the positive electrode active material is increased, the electrolyte solution is oxidatively decomposed, so that charge transfer that does not directly participate in charge / discharge occurs, and a side reaction tends to occur at the solid-liquid interface between the positive electrode and the electrolyte solution. When such a side reaction occurs, the positive electrode active material becomes oxidizable by electrochemical oxidation, and gas is generated by oxidative decomposition of the electrolytic solution, so that the internal pressure of the battery is increased and the battery components are increased. May be damaged. In addition, when metal ions are eluted from the positive electrode active material due to oxidative decomposition of the electrolytic solution, there is a risk of destroying the crystal structure of the positive electrode active material. May occur, and the separator may be damaged.

  Therefore, in order to avoid a side reaction from occurring at the solid-liquid interface due to direct contact between the surface of the positive electrode active material and the electrolyte, an oxide or fluoride of a metal such as aluminum or zirconium is used as the positive electrode active material. Has been proposed (see, for example, Patent Document 1).

  However, in this proposal, since these metal oxides and metal fluorides have non-conductivity, the electrical resistance of the positive electrode is increased, so that the electrochemical activity of the positive electrode is inhibited.

  In addition, as a means for suppressing side reactions from occurring on the surface of the positive electrode active material, it has been proposed to contain a phosphate ester in the electrolyte as an organic compound that imparts flame retardancy (for example, Non-Patent Document 1). reference).

  However, when a phosphate ester is included in the electrolyte as an organic compound that imparts flame retardancy, a film that prevents the migration of lithium ions is formed on the surface of the negative electrode made of graphite, etc. Is inhibited.

JP 2007-103119 A Junko Ozaki, Masafumi Higashiguchi, Aki Kita and Akira Kawakami, “Characteristics of Phosphate Ester Flame Retardant Electrolyte and Adaptation to Lithium Ion Secondary Batteries”, 1998 Electrochemical Fall Conference, 1998

  The present invention has been made in view of the above-described prior art. Even when a metal oxide or a metal fluoride is not used as a positive electrode active material, the generation of gas at the interface between the electrolytic solution and the positive electrode and the formation of metal ions are performed. Non-aqueous electrolyte secondary battery positive electrode material that suppresses elution and increases battery reliability and safety, a method for producing the same, and a non-aqueous electrolyte secondary battery having a positive electrode including the positive electrode material for non-aqueous electrolyte secondary battery It is an issue to provide.

The present invention
(1) A lithium group and at least one atom selected from the group consisting of a nickel atom, a cobalt atom, a manganese atom, an aluminum atom and a magnesium atom, and a space group R-3m type structure or a space group Fd3m type Compound oxide particles having a structure, and formula (I):

[Wherein R ¹ , R ² and R ³ are each independently an alkyl group having 1 to 22 carbon atoms, an aryl group having 6 to 18 carbon atoms, an aralkyl group having 7 to 18 carbon atoms, a formula: —R ^{A group represented by 4-} C (O) —O—R ⁵ (wherein R ⁴ represents an alkylene group having 1 to 6 carbon atoms, R ⁵ represents an alkyl group having 1 to 6 carbon atoms), a vinyl group, And a vinylalkyl group having 3 to 10 carbon atoms, a vinylaryl group having 8 to 20 carbon atoms, or a vinylarylalkyl group having 9 to 21 carbon atoms.
A positive electrode material for a non-aqueous electrolyte secondary battery, comprising a phosphonate compound represented by:

(2) a non-aqueous electrolyte secondary battery comprising a positive electrode, a negative electrode, a separator, and an electrolyte including the positive electrode material for a non-aqueous electrolyte secondary battery; and

(3) A lithium group and at least one atom selected from the group consisting of a nickel atom, a cobalt atom, a manganese atom, an aluminum atom and a magnesium atom, and a space group R-3m type structure or a space group Fd3m type To the composite oxide particles having a structure, formula (I):

[Wherein R ¹ , R ² and R ³ are each independently an alkyl group having 1 to 22 carbon atoms, an aryl group having 6 to 18 carbon atoms, an aralkyl group having 7 to 18 carbon atoms, a formula: —R ^{A group represented by 4-} C (O) —O—R ⁵ (wherein R ⁴ represents an alkylene group having 1 to 6 carbon atoms, R ⁵ represents an alkyl group having 1 to 6 carbon atoms), a vinyl group, And a vinylalkyl group having 3 to 10 carbon atoms, a vinylaryl group having 8 to 20 carbon atoms, or a vinylarylalkyl group having 9 to 21 carbon atoms.
It is related with the manufacturing method of the positive electrode material for nonaqueous electrolyte secondary batteries characterized by performing electrochemical oxidation after making the phosphonate compound represented by these.

  By using the positive electrode material for a non-aqueous electrolyte secondary battery of the present invention as a positive electrode, a metal oxide or a metal fluoride that may increase the electric resistance of a conventional positive electrode and hinder the electrochemical activity of the positive electrode may be used as a positive electrode. Even if it is not used as a substance, the generation of gas and the elution of metal ions at the interface between the electrolytic solution and the positive electrode are suppressed, and an excellent effect is achieved in that the reliability and safety of the battery are improved.

  In addition, since the nonaqueous electrolyte secondary battery of the present invention has a positive electrode containing the positive electrode material for a nonaqueous electrolyte secondary battery, when an electrochemical oxidation state is reached by a charging operation after the battery configuration, Since the generation of gas and the elution of metal ions at the interface with the positive electrode are suppressed, the battery is excellent in reliability and safety.

  The positive electrode material for a non-aqueous electrolyte secondary battery of the present invention contains a lithium atom and at least one atom selected from the group consisting of a nickel atom, a cobalt atom, a manganese atom, an aluminum atom, and a magnesium atom. Compound oxide particles having a group R-3m type structure or a space group Fd3m type structure, and the formula (I):

[Wherein R ¹ , R ² and R ³ are each independently an alkyl group having 1 to 22 carbon atoms, an aryl group having 6 to 18 carbon atoms, an aralkyl group having 7 to 18 carbon atoms, a formula: —R ^{A group represented by 4-} C (O) —O—R ⁵ (wherein R ⁴ represents an alkylene group having 1 to 6 carbon atoms, R ⁵ represents an alkyl group having 1 to 6 carbon atoms), a vinyl group, And a vinylalkyl group having 3 to 10 carbon atoms, a vinylaryl group having 8 to 20 carbon atoms, or a vinylarylalkyl group having 9 to 21 carbon atoms.
It has one big feature in that it contains a phosphonate compound represented by:

  Since the positive electrode material of the present invention has the above-described configuration, the non-aqueous electrolyte secondary battery having the positive electrode made of the positive electrode material of the present invention is configured, and then the non-aqueous electrolyte secondary battery is charged by a charge operation in a normally used charge / discharge process. When the positive electrode of a water electrolyte secondary battery reaches an electrochemically oxidized state, the generation of gas and the elution of metal ions at the interface between the electrolyte and the positive electrode are suppressed, improving the battery reliability and safety. It is done.

  The method for producing a positive electrode material of the present invention contains a lithium atom and at least one atom selected from the group consisting of a nickel atom, a cobalt atom, a manganese atom, an aluminum atom and a magnesium atom, and a space group R. It has one major feature in that after the phosphonate compound represented by the formula (I) is attached to a composite oxide particle having a -3m type structure or a space group Fd3m type structure, an electrochemical oxidation treatment is performed. .

  Since the method for producing a positive electrode material of the present invention employs the above-described operation, it constitutes a nonaqueous electrolyte secondary battery having a positive electrode made of a positive electrode material for a nonaqueous electrolyte secondary battery obtained by the production method of the present invention. Then, when the positive electrode of this non-aqueous electrolyte secondary battery reaches an electrochemical oxidation state by a charging operation in a normally used charge / discharge process, the generation of gas at the interface between the electrolytic solution and the positive electrode and Since elution of metal ions is suppressed, the reliability and safety of the battery are improved.

  The reason why the positive electrode material of the present invention has such an excellent effect is not clear, but it is probably that the phosphorus atom of the phosphonate compound is physically or chemically complex oxide particle through the oxygen atom of the complex oxide particle. Therefore, even if this composite oxide particle is subjected to an electrochemical oxidation treatment, the surface state is considered to be stabilized.

  More specifically, since the phosphonate compound is present on the surface of the composite oxide particle, when an electrochemical oxidation treatment is subsequently performed, the metal atoms present on the surface of the phosphonate compound and the composite oxide particle And the phosphonate compound is stably fixed on the surface of the composite oxide particle, and the alkyl group, aryl group, aralkyl group, etc. in the side chain of the phosphonate compound are oriented on the surface of the composite oxide particle via the phosphorus atom. However, this gently organicizes the surface of the composite oxide particles, which is presumed to be due to the relaxation of the polarization at the solid-liquid interface between the surface of the composite oxide particles and the electrolytic solution.

  Further, in the present invention, the phosphonate compound is attached to the composite oxide particles. However, since the phosphonate compound does not easily undergo a chemical reaction as compared with the phosphate ester compound, it is physically attached to the composite oxide particles. It is thought that it is adsorbed. Therefore, since the surface of the composite oxide particle is not chemically bonded to the phosphonate compound, the surface of the composite oxide particle is hardly blocked by the modified phosphonate compound when subjected to electrochemical oxidation treatment. It is considered that the electrical resistance of the positive electrode material to be increased is suppressed.

  Therefore, after constituting a battery having a positive electrode containing the positive electrode material of the present invention, when the positive electrode reaches an electrochemical oxidation state by a charging operation in the charge / discharge process, the polarization between the solid and the liquid of the positive electrode and the electrolyte, electrolysis Since generation of gas at the interface between the liquid and the positive electrode and elution of metal ions are suppressed, the reliability and safety of the battery are improved.

  The composite oxide particles used in the present invention contain a lithium atom and at least one atom selected from the group consisting of a nickel atom, a cobalt atom, a manganese atom, an aluminum atom and a magnesium atom, and a space group R- It has a 3m type structure or a space group Fd3m type structure.

  The composite oxide particles have a space group R-3m type structure or a space group Fd3m type structure because the composite oxide particles are used for a positive electrode material for a non-aqueous electrolyte secondary battery. The composite oxide particles preferably have a space group R-3m type structure having a layer structure or a space group Fd3m type structure having a spinel structure from the viewpoint of improving battery reliability and safety.

As composite oxide particles, the formula (II):
LiM _x O _y (II)
[Wherein, M is at least one atom selected from the group consisting of nickel atom, cobalt atom, manganese atom, aluminum atom and magnesium atom, x is a number of 0.8 to 2.3, and y is 1.7. Represents a number of ˜4.5, and x and y satisfy the formula: 1 + xn = 2y (where n represents the average oxidation number of the atom M and x and y are the same as above))
When the composite oxide particles having the space group R-3m type structure or the space group Fd3m type structure are used, the positive electrode including the positive electrode material of the present invention is used in the charge / discharge process. When an electrochemical oxidation state is reached by the charging operation, there is an advantage that generation of gas and elution of metal ions at the interface between the electrolytic solution and the positive electrode are further suppressed.

  In the formula (II), x is a number from 0.8 to 2.3, and y is a number from 1.7 to 4.5. x is a number of 0.8 or more, preferably 1 or more from the viewpoint of stably maintaining the crystal structure, and 2.3 from the viewpoint of improving the storage amount of lithium atoms per unit mass or unit volume. The following number, preferably a number of 2 or less. Moreover, y is a number of 1.7 or more, preferably 2 or more from the viewpoint of stably maintaining the crystal structure. From the viewpoint of improving the storage amount of lithium atoms per unit mass or unit volume, 4 is 4 .5 or less, preferably 4 or less.

  In the formula (II), M is at least one atom selected from the group consisting of nickel atom, cobalt atom, manganese atom, aluminum atom and magnesium atom. M is preferably at least one atom selected from the group consisting of a nickel atom, a cobalt atom, and a manganese atom from the viewpoint of increasing electrochemical stability.

  In the formula (II), x and y satisfy the formula: 1 + xn = 2y. In formula (II), 1 is the oxidation number of the lithium atom. x represents the number of atoms M, and n represents the average oxidation number of atoms M. Y represents the number of oxygen in the composite oxide particles. Therefore, the ratio of oxygen atoms to atoms M is defined by the formula (II).

Among the complex oxides represented by the formula (II), from the viewpoint of enhancing electrochemical stability, the formula (IIa):
LiNi _pq Map _(1-q) O _y (IIa)
(In the formula, Ma represents at least one atom selected from cobalt atom and manganese atom, p represents a number of 0.8 to 2.3, q represents a number of 0.01 to 0.99, and y represents the number Same as)
The composite oxide represented by is more preferable.

  In the formula (IIa), p is a number of 0.8 or more, preferably a number of 1 or more, from the viewpoint of stably maintaining the crystal structure, and improves the storage amount of lithium atoms per unit mass or unit volume. From the viewpoint, the number is 2.3 or less, preferably 2 or less. Further, q is a number of 0.01 or more, preferably 0.2 or more from the viewpoint of increasing the charge / discharge capacity, and is a number of 0.99 or less, preferably from the viewpoint of enhancing electrochemical stability. Is a number of 0.8 or less.

Among the complex oxides, it has a high energy density and low charge / discharge characteristics, so that the formula (IIb):
_{LiNi s Co t Mn u O y} (IIb)
(Wherein s is a number from 0.01 to 0.8, t is a number from 0.01 to 0.8, u is a number from 0.01 to 0.8, and the sum of s, t and u is 0.8 to 2.3, y is the same as above)
The composite oxide represented by is more preferable.

  In the formula (IIb), s is a number of 0.01 or more, preferably 0.3 or more, from the viewpoint of increasing the charge / discharge capacity, and 0.8 or less from the viewpoint of improving electrochemical stability. The number is preferably 0.7 or less. t is a number of 0.01 or more, preferably 0.2 or more from the viewpoint of increasing electrochemical stability and discharge potential, and from the viewpoint of increasing the charge / discharge capacity, t is a number of 0.8 or less, The number is preferably 0.5 or less. U is a number of 0.01 or more, preferably 0.2 or more, from the viewpoint of maintaining the crystal structure and enhancing the electrochemical stability. From the viewpoint of increasing the charge / discharge capacity, u is 0. .8 or less, preferably 0.5 or less. y is the same as described above.

  In the formula (IIb), the total amount of nickel atom, cobalt atom and manganese atom per lithium atom, that is, the sum of s, t and u is the viewpoint of increasing the charge / discharge capacity and the viewpoint of increasing the electrochemical stability. From 0.8 to 2.3, preferably 0.97 to 1.03.

  In the formula (IIb), the atomic ratio of nickel atom, cobalt atom and manganese atom [nickel atom (s): cobalt atom (t): manganese atom (u)] increases the energy density and charge / discharge with low polarizability. It is preferable to select arbitrarily so as to improve the characteristics, but from the viewpoint of reducing the change in the volume of the lattice during charging / discharging, it is more preferable that 1: 1, that is, s, t and u are the same.

  The composite oxide particles are prepared using, for example, a composite hydroxide of at least one atom selected from the group consisting of nickel atoms, cobalt atoms, manganese atoms, aluminum atoms, and magnesium atoms constituting the particles. Can do.

  As a raw material for the composite hydroxide, nickel salt, cobalt salt, manganese salt, aluminum salt and magnesium salt can be used. These salts are not particularly limited as long as ions generated in the aqueous solution can form a complex with the complexing agent.

  Specific examples of the nickel salt include nickel sulfate, nickel nitrate, nickel chloride and the like, and these can be used alone or in admixture of two or more.

  Specific examples of the cobalt salt include cobalt sulfate, cobalt nitrate, and cobalt chloride, and these can be used alone or in admixture of two or more.

  Specific examples of the manganese salt include manganese sulfate, manganese nitrate, manganese chloride and the like, and these can be used alone or in admixture of two or more.

  Specific examples of the aluminum salt include aluminum sulfate, aluminum nitrate, aluminum chloride and the like, and these can be used alone or in admixture of two or more.

  Specific examples of the magnesium salt include magnesium sulfate, magnesium nitrate, magnesium chloride and the like, and these can be used alone or in admixture of two or more.

  The amount of nickel salt, cobalt salt, manganese salt, aluminum salt and magnesium salt is adjusted so that the composition of the target composite oxide particles is obtained, and in the presence of a complexing agent in an inert gas atmosphere, for example, The salt is dissolved in an aqueous solution whose pH is adjusted to 9 to 13 using a pH adjusting agent such as sodium hydroxide or potassium hydroxide, and the resulting solution is reacted and coprecipitated to thereby form a composite hydroxide. Obtainable.

  Examples of the complexing agent include ammonium sulfate, ammonium chloride, ammonium carbonate, ammonium fluoride, hydrazine, ethylenediaminetetraacetic acid, nitrilotriacetic acid, uracil diacetic acid, glycine, and the like. These may be used alone or in combination of two or more. Can be mixed and used. The amount of complexing agent varies depending on the amount of metal ions contained in the solution and cannot be determined unconditionally. However, it usually forms a complex with metal ions, and the metal ions and water in the solution. What is necessary is just the quantity which produces a hydroxide by reaction with an oxide ion.

  The pH of the aqueous solution is preferably 9-13. When the pH of the aqueous solution varies by dissolving the salt, a pH adjuster may be appropriately added to the aqueous solution so as to be within the pH range. The liquid temperature of the aqueous solution is usually preferably about 30 to 60 ° C.

  The reaction is carried out in an inert gas atmosphere in order to maintain the valence of the metal contained in the salt to be divalent. Examples of the inert gas include nitrogen gas and argon gas, but the present invention is not limited to such examples.

  By carrying out the reaction in this manner, a composite hydroxide in which the atomic ratio of the raw material nickel atom, cobalt atom, manganese atom, aluminum atom and magnesium atom is an arbitrary ratio can be obtained. The obtained composite hydroxide contains the atomic ratio of nickel atom, cobalt atom, manganese atom, aluminum atom and magnesium atom in a desired ratio, and these atoms are uniformly dispersed at the atomic level. . The atomic ratio of nickel atom, cobalt atom, manganese atom, aluminum atom and magnesium atom in the obtained composite hydroxide can be determined by a metal element analysis method such as ICP emission spectroscopy.

  Next, the obtained composite hydroxide and lithium compound are sufficiently mixed in a powder state so as to obtain the desired composite oxide particle composition, and the obtained mixture is fired to obtain the composite oxide. Can be obtained.

  Examples of the lithium compound include lithium hydroxide, lithium carbonate, lithium nitrate, and lithium oxide, and these can be used alone or in admixture of two or more.

  The firing temperature of the mixture is usually preferably 700 to 1000 ° C, more preferably 900 to 1000 ° C, and still more preferably 950 to 1000 ° C. Moreover, the firing atmosphere should just be normally air | atmosphere.

  The firing time of the mixture varies depending on the firing conditions and cannot be determined unconditionally, but is usually the time required for forming the composite oxide by firing.

  Thus, a composite oxide is obtained. The atomic ratio of nickel atom, cobalt atom, manganese atom, aluminum atom and magnesium atom in the obtained composite oxide is determined by a metal element analysis method such as ICP emission spectroscopy. Can be obtained.

  When the obtained composite oxide does not have a desired particle diameter, it is preferable to grind the composite oxide as necessary. The average particle diameter of the composite oxide particles is preferably 100 nm to 100 μm, more preferably 5 to 50 μm, from the viewpoint of improving the operability during electrode preparation and increasing the electrochemical reaction field and increasing the electrode density. More preferably, it is 5-30 micrometers, More preferably, it is 7-12 micrometers. The average particle diameter of the composite oxide particles is a value obtained by observing with a microscope and measuring each diameter of the particles included in a certain range and obtaining the average value.

Next, the composite oxide particles and the phosphonate compound represented by the formula (I) are mixed.
In the phosphonate compound represented by the formula (I), the organic group represented by R ¹ , R ² and R ³ is bonded to the phosphorus atom directly or through an oxygen atom.

As a compound having a structure very similar to the phosphonate compound represented by the formula (I), R ¹ , R ² and R ³ are not an organic group, and a hydrogen atom is bonded directly or via an oxygen atom to a phosphorus atom. There is phosphoric acid. When phosphoric acid is used in place of the phosphonate compound represented by the formula (I), phosphoric acid is highly acidic and easily reacts directly with metal atoms, forming a strong chemical bond with the surface of the composite oxide particle. For this reason, there is a possibility that lithium ions may be prevented from moving into the positive electrode or the composite oxide may be modified.

In the formula (I), R ¹ , R ² and R ³ are each independently an alkyl group having 1 to 22 carbon atoms, an aryl group having 6 to 18 carbon atoms, an aralkyl group having 7 to 18 carbon atoms, a formula: A group represented by —R ⁴ —C (O) —O—R ⁵ (wherein R ⁴ represents an alkylene group having 1 to 6 carbon atoms, and R ⁵ represents an alkyl group having 1 to 6 carbon atoms), vinyl Group, a vinylalkyl group having 3 to 10 carbon atoms, a vinylaryl group having 8 to 20 carbon atoms, or a vinylarylalkyl group having 9 to 21 carbon atoms.

Preferably, R ¹ , R ² and R ³ each independently represent an alkyl group having 1 to 22 carbon atoms, an aryl group having 6 to 18 carbon atoms, an aralkyl group having 7 to 18 carbon atoms, a formula: —R ⁴ A group represented by —C (O) —O—R ⁵ (wherein R ⁴ and R ⁵ are the same as those described above), a vinyl group, or a vinylalkyl group having 3 to 10 carbon atoms. More preferably, R ¹ , R ² and R ³ each independently represent an alkyl group having 1 to 22 carbon atoms, an aryl group having 6 to 18 carbon atoms, an aralkyl group having 7 to 18 carbon atoms, a formula: —R ^4- C (O) —O—R ⁵ (wherein R ⁴ and R ⁵ are the same as above) or a vinyl group.

In the formula (I), R ¹ , R ² and R ³ may be the same or different from each other.

Note that R ¹ , R ^2, and R ³ all have a concept that may have a substituent as long as the object of the present invention is not inhibited.

  In the formula (I), the alkyl group having 1 to 22 carbon atoms may be linear or branched. The number of carbon atoms of the alkyl group is 1 or more from the viewpoint of suppressing the transformation to the phosphite ester which is an isomer, increasing the mobility of lithium ions on the surface of the composite oxide particles, and increasing the charge / discharge capacity. From the viewpoint of increasing, it is 22 or less, preferably 18 or less, more preferably 12 or less, and still more preferably 8 or less. Therefore, the alkyl group has 1 to 22 carbon atoms, preferably 1 to 18 carbon atoms, more preferably 1 to 12 carbon atoms, and further preferably 1 to 8 carbon atoms.

  In the formula (I), examples of the aryl group having 6 to 18 carbon atoms include a phenyl group, a tolyl group, a xylyl group, a biphenyl group, a naphthyl group, an anthryl group, and a phenanthryl group. Among these, an aryl group having 6 to 8 carbon atoms is preferable from the viewpoint of increasing the mobility of lithium ions on the surface of the composite oxide particle and increasing the charge / discharge capacity.

  In the formula (I), the aralkyl group is also referred to as an arylalkyl group. Examples of the aralkyl group having 7 to 18 carbon atoms include a phenylmethyl group, a 2-phenylethyl group, a 3-phenylpropyl group, and a 4-phenylbutyl group. Among these, an aralkyl group having 7 to 9 carbon atoms is preferable from the viewpoint of increasing the mobility of lithium ions on the surface of the composite oxide particle and increasing the charge / discharge capacity.

In the formula (I), the group represented by the formula: —R ⁴ —C (O) —O—R ⁵ has an alkoxycarbonyl group. In the formula, R ⁴ is an alkylene group having 1 to 6 carbon atoms, preferably an alkylene group having 1 to 4 carbon atoms. R ⁵ is an alkyl group having 1 to 6 carbon atoms, preferably an alkyl group having 1 to 4 carbon atoms.

  In the formula (I), examples of the vinylalkyl group having 3 to 10 carbon atoms include a vinylmethyl group, a vinylethyl group, and a vinylpropyl group.

  In the formula (I), examples of the vinyl aryl group having 8 to 20 carbon atoms include a vinylphenyl group.

  In the formula (I), examples of the vinylarylalkyl group having 9 to 21 carbon atoms include a vinylphenylmethyl group and a vinylphenylmethyl group.

  Among the phosphonate compounds, dimethyl methyl phosphonate, dimethyl ethyl phosphonate, dipropyl methyl phosphonate, dibutyl methyl phosphonate, diphenyl methyl phosphonate, dibenzyl methyl phosphonate, dimethyl vinyl phosphonate, diethyl vinyl phosphonate, dimethyl octadecyl phosphonate, dimethyl benzyl phosphonate, diethyl benzyl At least one phosphonate compound selected from the group consisting of phosphonate, ethyl diethyl phosphonoacetate, dimethylphenyl phosphonate, dimethyloctyl phosphonate and dimethyl (diphenylmethyl) phosphonate has a mobility of lithium ions on the surface of the composite oxide particle. It is preferable from the viewpoint of increasing the charge / discharge capacity.

  As a method of mixing the composite oxide particles and the phosphonate compound, for example, from the viewpoint of ease of operation, a solution in which the phosphonate compound is dissolved as it is or in an appropriate organic solvent is mixed with the composite oxide particles. The method of doing is mentioned. Thereby, a phosphonate compound can be made to adhere to the surface of complex oxide particles.

  When a liquid phosphonate compound is used, it can be attached to the composite oxide particles as it is or as a solution dissolved in an appropriate organic solvent. Further, when a solid phosphonate compound is used, it can be attached to the composite oxide particles as a solution dissolved in an appropriate organic solvent.

  As a specific method for mixing the composite oxide particles and the phosphonate compound, for example, the composite oxide particles are added to the composite oxide particles while stirring the composite oxide particles. And a method of mixing the phosphonate compound with a uniform composition. When mixing the composite oxide particles and the phosphonate compound, they may be charged together and mixed, or they may be mixed by gradually blending them.

  When a solution in which a phosphonate compound is dissolved in an appropriate organic solvent is attached to the composite oxide particles, there is an advantage that a small amount of the phosphonate compound can be uniformly attached to the surface of the composite oxide particles. In this case, a method of spraying the solution of the phosphonate compound onto the composite oxide particles being stirred by spraying, a method of adding the composite oxide particles to the solution of the phosphonate compound, and adhering by immersing may be mentioned. However, the present invention is not limited to only such examples.

  Examples of the organic solvent include N-methylpyrrolidone (NMP), ethylene carbonate, propylene carbonate, γ-butyrolactone, acetone, methyl ethyl ketone, benzene, toluene, glyme, diglyme, triglyme, diethyl ether, diisopropyl ether, and the like. The present invention is not limited to such examples. Since the amount of the organic solvent varies depending on the amounts of the composite oxide particles and the phosphonate compound, it cannot be generally determined. However, usually, the amount of the organic solvent is 5 to 70 masses per 100 parts by mass of the total amount of the composite oxide particles and the phosphonate compound. It is preferable that it is about a part.

  As will be described later, when assembling a battery, generally, an operation of mixing a positive electrode material, a conductive agent and a binder, applying the obtained paste to a current collector, and drying it is employed. However, in the present invention, the phosphonate compound can be added to the surface of the composite oxide particles when the composite oxide particles, the conductive agent and the binder are mixed. In this case, the phosphonate compound is preferably used, for example, as a solution in which the phosphonate compound is dissolved in an organic solvent such as N-methylpyrrolidone (NMP) used when preparing the paste.

  Thus, adding the phosphonate compound when mixing the composite oxide particles, the conductive agent and the binder eliminates the need to mix the composite oxide particles and the phosphonate compound, and dissolves the phosphonate compound. Since it is not necessary to remove the organic solvent used only for the purpose, it is preferable from the viewpoint of increasing productivity.

  When using a solution in which a phosphonate compound is dissolved in an organic solvent, the organic solvent is removed as much as possible by, for example, heat drying or vacuum drying after the phosphonate compound solution is attached to the composite oxide particles. Is preferred.

The amount of the phosphonate compound is preferably 0.1 per 100 parts by mass of the composite oxide particles from the viewpoint of sufficiently suppressing gas generation due to oxidative decomposition of the electrolytic solution and suppressing elution of metal ions. It is at least 0.3 parts by mass, more preferably at least 0.3 parts by mass. In addition, when the amount of the phosphonate compound per 100 parts by mass of the composite oxide particles is less than 0.1 parts by mass, the entire composite oxide particles must be formed unless the phosphonate compound is adhered to the surface of the composite oxide particles in a single molecular unit. It is speculated that it is theoretically difficult to cover the surface with a phosphonate compound because the BET specific surface area of the composite oxide particles is 0.39 m ² / g.

  Further, the amount of the phosphonate compound is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, from the viewpoint of increasing lithium ion mobility and increasing charge / discharge capacity per 100 parts by mass of the composite oxide particles. In addition, when the amount of the phosphonate compound per 100 parts by mass of the composite oxide particles is about 5 parts by mass, it can be considered macroscopically that the phosphonate compound is attached to the composite oxide particles in a film shape. Actually, since the charge / discharge capacity does not decrease so much, it is considered that the phosphonate compound is scattered and adhered to the composite oxide particles.

  Next, electrochemical oxidation treatment is performed on the composite oxide particles to which the phosphonate compound is attached.

As the electrochemical oxidation treatment, for example,
(A) A test electrode is constituted by using composite oxide particles to which a phosphonate compound is adhered, a negative electrode made of a carbon material is used as a counter electrode of the test electrode, and an electric device is provided between the test electrode and the negative electrode through an electrolyte and a separator. A method of applying an electrochemical oxidation treatment to the composite oxide particles to which the phosphonate compound is adhered by applying an oxidation current to the test electrode,
(B) In an electrolytic cell having an electrolytic solution containing a lithium salt as a supporting electrolyte, an electrode made of lithium metal or a pseudo counter electrode capable of occluding lithium, and a test electrode composed of composite oxide particles to which a phosphonate compound is attached, And a method of applying an electrochemical oxidation treatment to the composite oxide particles to which the phosphonate compound is adhered by applying an oxidation current to the test electrode. In the present invention, at least one of these methods can be used.

  In the method (A), after the test electrode comes into contact with the electrolyte, an oxidation current of about 0.1 C per hour is applied to the test electrode to obtain a potential of 4.0 V or more and less than 4.3 V on the basis of the lithium potential. It is preferable to apply an energization process until it is obtained. In the method (A), since the test electrode and the counter electrode are formed in the same electrical equipment, this test electrode can be used as a positive electrode and used as it is as a battery device.

  In the method (B), after the test electrode comes into contact with the electrolytic solution, an oxidation current having a time rate of 3C or more is instantaneously applied to the test electrode for about 0.1 to 3 milliseconds, and then the energization is stopped. From the viewpoint of securing the charge capacity as the active material when the battery is configured, after energization is stopped and 5 minutes have elapsed, a potential increase of 0.05 V or more and less than 0.08 V is caused from the initial open circuit potential. It is preferred to apply an oxidation current to the test electrode. In the case of using a wet electrode, the electrode is dried in advance at a temperature of about room temperature to 50 ° C., and the reduction rate of the mass of the electrode may be 0.1% by mass or less of the mass before the treatment.

  In the method (A) or the method (B), a solid-liquid interface between a test electrode to be used later as a positive electrode and an electrolytic solution is formed, but a composite test electrode constituting the test electrode is formed. Since the phosphonate compound is adsorbed on the surface of the composite oxide particle during the electrochemical oxidation process, groups such as aryl groups and aralkyl groups, which are side chains of the phosphonate compound, have phosphorus atoms on the surface of the composite oxide particle. It is considered that the surface of the composite oxide particles is gently organicized. From this, it is considered that the polarization of the solid-liquid interface between the surface of the test electrode and the electrolyte is relaxed, and rapid oxidation of the solvent molecules is avoided.

  In addition, since it is considered that the phosphonate compound is present at a relatively high density on the surface of the composite oxide particles constituting the test electrode, the composite oxide is subjected to a charging operation in the charge / discharge process after the battery is constructed. When the particles have reached an electrochemically strong oxidation state, it is considered that the generation of gas and the elution of metal ions at the solid-liquid interface between the composite oxide particles and the electrolytic solution are suppressed by the phosphonate compound.

  In addition, since the phosphonate compound is used in the positive electrode material of the present invention, the same mechanism as the flame retardant mechanism of the phosphorus-based flame retardant occurs, so when the positive electrode containing the positive electrode material of the present invention is used. , Battery reliability and safety are increased.

In the methods (A) and (B), both can be operated at room temperature. In these methods, for example, a mixed solution of propylene carbonate and diethylene carbonate containing 0.5 to 2 mol / dm ³ of LiPF ₆ can be used as the electrolytic solution. At this time, the volume ratio of propylene carbonate to diethylene carbonate (propylene carbonate / diethylene carbonate) is preferably 0.5 / 1.5 to 1.5 / 0.5.

  When the positive electrode containing the positive electrode material for a non-aqueous electrolyte secondary battery of the present invention is used, when the positive electrode reaches an electrochemical oxidation state by a charging operation, gas generation at the interface between the electrolytic solution and the positive electrode and Since elution of metal ions is suppressed, the reliability and safety of the battery can be improved.

  The nonaqueous electrolyte secondary battery of the present invention contains a positive electrode, a negative electrode, a separator, and an electrolyte containing the positive electrode material for a nonaqueous electrolyte secondary battery.

  The positive electrode is obtained, for example, by mixing the positive electrode material for a non-aqueous electrolyte secondary battery, a conductive agent and a binder, applying the obtained paste to a current collector, and drying.

  The conductive agent is not particularly limited as long as it is an electron conductive material that does not cause a chemical change in the battery.

  Examples of the conductive agent include natural graphite such as flake graphite, graphite such as artificial graphite; carbon black such as acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black; carbon fiber, metal fiber, etc. Conductive fiber; Carbon fluoride; Powder of metal such as copper, nickel, aluminum, silver; Conductive whisker such as zinc oxide and potassium titanate; Conductive metal oxide such as titanium oxide; Organic conductivity such as polyphenylene derivative These may be used alone or in any combination as long as the object of the present invention is not impaired. Of these, artificial graphite, acetylene black and nickel powder are preferred.

  The amount of the conductive agent is not particularly limited, but is usually preferably 2 to 5 parts by mass, more preferably 2.5 to 3.5 parts by mass, per 100 parts by mass of the positive electrode material for a non-aqueous electrolyte secondary battery. .

  The binder is preferably a polymer having a decomposition temperature of 300 ° C. or higher. Specific examples of the binder include polyethylene, polypropylene, polytetrafluoroethylene, polyvinylidene fluoride, tetrafluoroethylene-hexafluoroethylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-perfluoro. Alkyl vinyl ether copolymer, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-chlorotrifluoroethylene copolymer, ethylene-tetrafluoroethylene copolymer, polychlorotrifluoroethylene, vinylidene fluoride-pentafluoro Propylene copolymer, propylene-tetrafluoroethylene copolymer, ethylene-chlorotrifluoroethylene copolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoro Tylene copolymer, vinylidene fluoride-perfluoromethyl vinyl ether-tetrafluoroethylene copolymer, etc. may be mentioned, and these may be used alone or in any mixture within the range in which the object of the present invention is not impaired. Can do. Of these, polyvinylidene fluoride and polytetrafluoroethylene are preferred.

  The amount of the binder is not particularly limited, but is usually preferably 3 to 10 parts by mass, more preferably 5 to 7 parts by mass, per 100 parts by mass of the positive electrode material for a nonaqueous electrolyte secondary battery.

  A paste is obtained by mixing a positive electrode material for a non-aqueous electrolyte secondary battery, a conductive agent, and a binder, and the obtained paste is applied to a current collector.

  As described above, when preparing this paste, when the phosphonate compound is mixed with the paste, the phosphonate compound can be attached to the surface of the composite oxide particle when the mixing is performed.

  The current collector is not particularly limited as long as it is an electron conductor that hardly causes a chemical change in the battery. Examples of the material constituting the current collector include aluminum, aluminum alloy, stainless steel, nickel, titanium, and carbon, as well as a composite in which carbon, nickel, titanium, or silver is attached to the surface of aluminum or stainless steel. Is mentioned. Of these, aluminum and aluminum alloys are preferred.

  Note that the surface of the current collector may be oxidized, or irregularities may be formed on the surface by surface treatment.

  The shape of the current collector may be anything that is generally used for batteries. Specific examples of the shape of the current collector include foil, film, sheet, net, lath body, porous body, foam, fiber, woven fabric, and non-woven fabric. Although the thickness of a collector is not specifically limited, Usually, what is necessary is just about 1-50 micrometers.

  Although the electrode density after apply | coating the said paste to a collector is not specifically limited, Usually, what is necessary is just about 3.0-3.8 g / mL.

  Next, the positive electrode is obtained by drying the current collector coated with the paste by a conventional method.

  The negative electrode material used for the negative electrode may be any compound that can occlude or release lithium ions, such as lithium, lithium alloys, intermetallic compounds, and carbon materials. These negative electrode materials can be used alone or in any combination as long as the object of the present invention is not impaired.

  Examples of lithium alloys include Li-Al alloys, Li-Al-Mn alloys, Li-Al-Mg alloys, Li-Al-Sn alloys, Li-Al-In alloys, Li-Al-Cd. Alloy, Li—Al—Te alloy, Li—Ga alloy, Li—Cd alloy, Li—In alloy, Li—Pb alloy, Li—Bi alloy, Li—Mg alloy, etc. However, the present invention is not limited to such examples. The lithium content in the lithium alloy is preferably 10% by mass or more.

  Examples of the intermetallic compound include a transition metal / silicon compound, a transition metal / tin compound, and the like.

  Examples of the carbon material include carbon fibers such as polyacrylonitrile-based carbon fiber, pitch-based carbon fiber, cellulose-based carbon fiber, and vapor-grown carbon-based carbon fiber, coke, pyrolytic carbon, natural graphite, artificial graphite, and mesocarbon micro. Examples include beads, graphitized mesophase spherules, vapor-grown carbon, glassy carbon, poly-amorphous carbon, etc., and these may be used alone or in any combination as long as the object of the present invention is not impaired. Can do.

  The separator is preferably a microporous thin film having high ion permeability and mechanical strength, such as a sheet made of olefin polymer such as polypropylene and polyethylene, glass fiber, and non-woven fabric, and having insulating properties, organic solvent resistance and hydrophobicity. .

  In general, the pore diameter of the separator is preferably 0.1 to 1 μm. The thickness of the separator may be about 10 to 100 μm. In addition, the porosity of the separator is determined according to the permeability of electrons and ions, but is generally preferably about 30 to 80%.

  The electrolytic solution is obtained by dissolving the electrolyte in an organic solvent. Examples of the organic solvent include cyclic carbonates such as ethylene carbonate, propylene carbonate, butylene carbonate, and vinylene carbonate; acyclic carbonates such as dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, and dipropyl carbonate; methyl formate, methyl acetate, and propionic acid Aliphatic carboxylic acid esters such as methyl and ethyl propionate; γ-lactones such as γ-butyrolactone (GBL); acyclic ethers such as 1,2-dimethoxyethane, 1,2-diethoxyethane and ethoxymethoxyethane; tetrahydrofuran Cyclic ethers such as 2-methyltetrahydrofuran; dimethyl sulfoxide, formamide, acetamide, dimethylformamide, dioxolane, dioxolane derivatives, Acetonitrile, propylnitrile, nitromethane, ethyl monoglyme, phosphoric acid triester, trimethoxymethane, sulfolane, methylsulfolane, 1,3-dimethyl-2-imidazolidinone, 3-methyl-2-oxazolidinone, propylene carbonate derivative, tetrahydrofuran Derivatives, 1,3-propane sultone, anisole, dimethyl sulfoxide, N-methylpyrrolidone and the like can be mentioned, but the present invention is not limited to such examples. These organic solvents can be used alone or in any combination as long as the object of the present invention is not impaired.

The electrolyte is preferably a non-aqueous electrolyte. Examples of non-aqueous electrolytes include LiClO ₄ , LiBF ₄ , LiPF ₆ , LLiAlCl ₄ , LiSbF ₆ , LiSCN, LiCF ₃ SO ₃ , LiCF ₃ CO ₂ , Li (CF ₃ SO ₂ ) ₂ , LiAsF ₆ , LiN (CF ₃ SO ₂ ) ₂ , LiB ₁₀ Cl ₁₀ , LiCl, LiBr, LiI, LiN (CF ₃ SO ₂ ) (C ₂ F ₅ SO ₂ ), 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 ), lower aliphatic lithium carboxylate, lithium chloroborane, lithium tetraphenylborate and the like, but the present invention is limited to such examples only. It is not something. These electrolytes can be used alone or in any combination as long as the object of the present invention is not impaired.

  The amount of the electrolyte per liter of the organic solvent is not particularly limited, but is preferably 0.2 to 2 mol, more preferably 0.5 to 1.5 mol.

  For the electrolytic solution, 2-methylfuran, thiophene, pyrrole, aniline, crown ether, pyridine, triethyl phosphite, triethanolamine, cyclic ether, ethylenediamine, n-glyme, hexaphosphoric acid from the viewpoint of enhancing charge / discharge characteristics. Triamide, nitrobenzene derivatives and the like may be dissolved.

  Further, in order to impart nonflammability to the electrolytic solution, for example, a halogen-containing organic solvent such as carbon tetrachloride or ethylene trifluoride chloride may be included in the electrolytic solution. Furthermore, carbon dioxide may be blown into the electrolytic solution from the viewpoint of imparting storage stability at high temperatures to the electrolytic solution.

  The electrolytic solution can usually be used by impregnating a separator such as a porous polymer, a glass filter, or a nonwoven fabric.

  Examples of the shape of the battery include a coin shape, a button shape, a sheet shape, a cylindrical shape, a flat shape, and a square shape. When the shape of the battery is a coin type or a button type, it can be used by forming a positive electrode active material or a negative electrode material into a pellet shape. What is necessary is just to determine the thickness and diameter of a pellet-shaped battery suitably according to the use etc. of a battery.

  As described above, since the non-aqueous electrolyte secondary battery of the present invention uses the positive electrode material for the non-aqueous electrolyte secondary battery for the positive electrode, the gas is not released when the electrochemical oxidation state is reached by the charging operation. Since there is almost no generation | occurrence | production and ion elution, it is excellent in the reliability and safety | security.

  Next, the present invention will be described in more detail based on examples. However, the present invention is not limited to such examples.

Production Example 1 (Production of composite oxide particles A)
Into a 15 L (liter) cylindrical reaction vessel equipped with a stirrer and an overflow pipe, 13 L of water was added, and then a 30% aqueous sodium hydroxide solution was added until the pH reached 10.9. Stirring was performed while nitrogen gas was blown into the aqueous solution at a flow rate of 0.5 L / min to remove dissolved oxygen.

  On the other hand, a 1.7 mol / L nickel sulfate aqueous solution, a 1.5 mol / L cobalt sulfate aqueous solution and a 1.1 mol / L manganese sulfate aqueous solution are prepared so that the atomic ratio of nickel atoms, cobalt atoms and manganese atoms is 1: 1: 1. Mixed. A 6 mol / L ammonium sulfate aqueous solution was added to the obtained mixed solution at a rate of 50 mL per 1 L of the mixed solution. In order to remove dissolved oxygen in the mixed solution, a 4% by mass hydrazine aqueous solution was added at a rate of 13 mL per liter of the mixed solution to prepare a mixed raw material solution.

  Next, this mixed raw material solution is continuously added to the cylindrical reaction vessel at a flow rate of 10 mL / min, and 30% sodium hydroxide is added so that the pH of the solution in the reaction vessel becomes 10.9. The nickel-cobalt-manganese composite hydroxide particles were obtained by intermittent addition.

  After the reaction vessel is in a steady state, nickel-cobalt-manganese composite hydroxide particles are continuously collected from the overflow pipe, washed with water, filtered, and dried at a temperature of 100 ° C. for 15 hours. -A dry powder of cobalt-manganese composite hydroxide was obtained.

  Next, the lithium hydroxide monohydrate was weighed so that the atomic ratio of lithium atoms to the total of nickel atoms, cobalt atoms, and manganese atoms in the obtained nickel-cobalt-manganese composite hydroxide was 1.03. The lithium hydroxide monohydrate and the nickel-cobalt-manganese composite hydroxide dry powder were thoroughly mixed, and the resulting mixture was calcined in air at a temperature of 1000 ° C. for 10 hours. A composite oxide was obtained. The obtained composite oxide was pulverized to obtain composite oxide particles having a particle size of 20 μm or less.

The obtained composite oxide particles have an atomic ratio of nickel atoms, cobalt atoms, and manganese atoms of 1: 1: 1, have a space group R-3m type structure, and have the formula: LiNi _0.33 Co _0.33 It was represented by Mn _0.33 O _2.00 . Hereinafter, the composite oxide particles are referred to as composite oxide particles A.

  In addition, the structure of the space group of the composite oxide particles obtained in each production example was confirmed by X-ray diffraction.

Production Example 2 (Production of composite oxide particle B)
In a 15 L cylindrical reactor equipped with a stirrer and overflow pipe, 13 L of water was added, and then 30% aqueous sodium hydroxide solution was added until the pH reached 10.9, and the liquid temperature was maintained at 50 ° C. Then, nitrogen gas was blown into this aqueous solution at a flow rate of 0.5 L / min to perform stirring while removing dissolved oxygen.

  On the other hand, a 1.7 mol / L nickel sulfate aqueous solution, a 1.5 mol / L cobalt sulfate aqueous solution and a 1.1 mol / L manganese sulfate aqueous solution are prepared so that the atomic ratio of nickel atoms, cobalt atoms and manganese atoms is 8: 1: 1. Mixed. A 6 mol / L ammonium sulfate aqueous solution was added to the obtained mixed solution at a rate of 50 mL per 1 L of the mixed solution. In order to remove dissolved oxygen in the mixed solution, a 4% by mass hydrazine aqueous solution was added at a rate of 13 mL per liter of the mixed solution to prepare a mixed raw material solution.

  Next, this mixed raw material solution is continuously added to the cylindrical reaction vessel at a flow rate of 10 mL / min, and 30% sodium hydroxide is added so that the pH of the solution in the reaction vessel becomes 10.9. The nickel-cobalt-manganese composite hydroxide particles were obtained by intermittent addition.

  After the reaction vessel is in a steady state, nickel-cobalt-manganese composite hydroxide particles are continuously collected from the overflow pipe, washed with water, filtered, and dried at a temperature of 100 ° C. for 15 hours. -A dry powder of cobalt-manganese composite hydroxide was obtained.

  Next, the lithium hydroxide monohydrate was weighed so that the atomic ratio of lithium atoms to the total of nickel atoms, cobalt atoms, and manganese atoms in the obtained nickel-cobalt-manganese composite hydroxide was 1.03. The lithium hydroxide monohydrate and the nickel-cobalt-manganese composite hydroxide dry powder were thoroughly mixed, and the resulting mixture was calcined in air at a temperature of 1000 ° C. for 10 hours. A composite oxide was obtained. The obtained composite oxide was pulverized to obtain composite oxide particles having a particle size of 20 μm or less.

The obtained composite oxide particles have an atomic ratio of nickel atoms, cobalt atoms, and manganese atoms of 8: 1: 1, have a space group R-3m type structure, and have the formula: LiNi _0.80 Co _0.10. It was represented by Mn _0.10 O _2.00 . Hereinafter, the composite oxide particles are referred to as composite oxide particles B.

Production Example 3 (Production of Composite Oxide Particle C)
In a 15 L cylindrical reactor equipped with a stirrer and overflow pipe, 13 L of water was added, and then 30% aqueous sodium hydroxide solution was added until the pH reached 10.9, and the liquid temperature was maintained at 50 ° C. Then, stirring was performed while nitrogen gas was blown into the aqueous solution at a flow rate of 0.5 L / min to remove dissolved oxygen.

  On the other hand, a 1.7 mol / L nickel sulfate aqueous solution and a 1.5 mol / L cobalt sulfate aqueous solution were mixed so that the atomic ratio of nickel atoms to cobalt atoms was 1: 1. A 6 mol / L ammonium sulfate aqueous solution was added to the obtained mixed solution at a rate of 50 mL per 1 L of the mixed solution. In order to remove dissolved oxygen in the mixed solution, a 4% by mass hydrazine aqueous solution was added to the mixed solution at a rate of 13 mL per liter of the mixed solution to prepare a mixed raw material solution.

  Next, this mixed raw material solution is continuously added to the cylindrical reaction vessel at a flow rate of 10 mL / min, and 30% sodium hydroxide is added so that the pH of the solution in the reaction vessel becomes 10.9. The nickel-cobalt composite hydroxide particles were obtained by intermittent addition.

  After the reaction vessel is in a steady state, nickel-cobalt composite hydroxide particles are continuously collected from the overflow pipe, washed with water, filtered, and dried at a temperature of 100 ° C. for 15 hours. A dry powder of composite hydroxide was obtained.

  Next, lithium hydroxide monohydrate was weighed so that the total amount of nickel atoms and cobalt atoms in the obtained nickel-cobalt composite hydroxide and the atomic ratio of lithium atoms was 1: 1.03. The lithium hydroxide monohydrate and the dry powder of nickel-cobalt composite hydroxide were thoroughly mixed, and the resulting mixture was calcined at 750 ° C. for 10 hours in the air atmosphere to obtain composite oxidation. I got a thing. The obtained composite oxide was pulverized to obtain composite oxide particles having a particle size of 20 μm or less.

The obtained composite oxide particles have an atomic ratio of nickel atom to cobalt atom of 1: 1, a space group R-3m type structure, and a formula: LiNi _0.50 Co _0.50 O _2.00 It was what was represented. Hereinafter, the composite oxide particles are referred to as composite oxide particles C.

Production Example 4 (Production of composite oxide particle D)
In a 15 L cylindrical reactor equipped with a stirrer and overflow pipe, 13 L of water was added, and then 30% aqueous sodium hydroxide solution was added until the pH reached 11.9, and the liquid temperature was maintained at 50 ° C. Then, nitrogen gas was blown into this aqueous solution at a flow rate of 0.5 L / min to perform stirring while removing dissolved oxygen.

  Next, a 1.5 mol / L cobalt sulfate aqueous solution was prepared as a raw material solution for obtaining cobalt hydroxide. A 6 mol / L ammonium sulfate aqueous solution was added to this aqueous solution at a rate of 50 mL per 1 L of this cobalt sulfate aqueous solution. In order to remove dissolved oxygen in the obtained mixed solution, a 4% by mass hydrazine aqueous solution was added to the mixed solution at a rate of 13 mL per 1 L of the mixed solution to prepare a mixed raw material solution.

  Next, this mixed raw material solution is continuously added to the cylindrical reaction vessel at a flow rate of 10 mL / min, and 30% sodium hydroxide is added so that the pH of the solution in the reaction vessel becomes 11.9. Add intermittently to obtain cobalt hydroxide particles.

  After the reaction vessel is in a steady state, cobalt hydroxide particles are continuously collected from the overflow pipe, washed with water, filtered, and dried at a temperature of 60 ° C. for 15 hours to dry the cobalt hydroxide. A powder was obtained.

  Next, lithium hydroxide monohydrate was weighed so that the atomic ratio of cobalt atoms to lithium atoms in the obtained cobalt hydroxide was 1: 1.03, and this lithium hydroxide monohydrate and cobalt The composite oxide was obtained by thoroughly mixing with the hydroxide dry powder and firing the resulting mixture at a temperature of 850 ° C. for 10 hours in an air atmosphere. The obtained composite oxide was pulverized to obtain composite oxide particles having a particle size of 20 μm or less.

The obtained composite oxide particles had a space group R-3m type structure and were represented by the formula: LiCo _1.00 O _2.00 . Hereinafter, the composite oxide particles are referred to as composite oxide particles D.

Production Example 5 (Production of composite oxide particles E)
In a 15 L cylindrical reaction vessel equipped with a stirrer and an overflow pipe, 13 L of water was added, and then a 30% aqueous sodium hydroxide solution was added until the pH reached 11.4. Stirring was performed while removing dissolved oxygen by blowing at a flow rate of 0.5 L / min.

  On the other hand, a 1.7 mol / L nickel sulfate aqueous solution and a 1 mol / L manganese sulfate aqueous solution were mixed so that the atomic ratio of nickel atoms to manganese atoms was 1: 1. A 6 mol / L ammonium sulfate aqueous solution was added at a rate of 50 mL per 1 L of the mixed solution. In order to remove dissolved oxygen in the mixed solution, a 4% by mass hydrazine aqueous solution was added at a rate of 13 mL per liter of the mixed solution to prepare a mixed raw material solution.

  Next, this mixed raw material solution is continuously added to the cylindrical reaction vessel at a flow rate of 10 mL / min, and 30% sodium hydroxide is intermittently added so that the solution in the reaction vessel has a pH of 11.4. To obtain nickel-manganese composite hydroxide particles.

  After the reaction vessel is in a steady state, nickel-manganese composite hydroxide particles are continuously collected from the overflow pipe, washed with water, filtered, and dried at a temperature of 100 ° C. for 15 hours. A dry powder of composite hydroxide was obtained.

  Next, lithium hydroxide monohydrate was weighed so that the atomic ratio of lithium atoms to the total of nickel atoms and manganese atoms in the obtained nickel-manganese composite hydroxide was 1: 1.03. Lithium hydroxide monohydrate and nickel-manganese composite hydroxide dry powder are thoroughly mixed, and the resulting mixture is fired at 1000 ° C. for 10 hours in an air atmosphere, thereby producing a composite oxide. Obtained. The obtained composite oxide was pulverized to obtain composite oxide particles having a particle size of 20 μm or less.

The obtained composite oxide particles have an atomic ratio of nickel atom to manganese atom of 1: 1, a space group R-3m type structure, and a formula: LiNi _0.50 Mn _0.50 O _2.00 It was what was represented. Hereinafter, the composite oxide particles are referred to as composite oxide particles E.

Production Example 6 (Production of composite oxide particles F)
Into a 15 L cylindrical reactor equipped with a stirrer and an overflow pipe, 13 L of water was added, and then a 30% aqueous sodium hydroxide solution was added until the pH reached 11.9, and the temperature was maintained at 50 ° C. Stirring was performed.

  On the other hand, a 1.7 mol / L nickel sulfate aqueous solution was prepared as a raw material solution for obtaining nickel hydroxide. A 6 mol / L ammonium sulfate aqueous solution was added at a rate of 50 mL per 1 L of this solution to prepare a mixed raw material solution.

  Next, this mixed raw material solution is continuously added to the cylindrical reaction vessel at a flow rate of 10 mL / min, and 30% sodium hydroxide is added so that the pH of the solution in the reaction vessel becomes 11.9. The nickel hydroxide particles were obtained by intermittent addition.

  After the reaction vessel is in a steady state, nickel hydroxide particles are continuously collected from the overflow pipe, washed with water, filtered, and dried at a temperature of 100 ° C. for 15 hours to dry the nickel hydroxide. A powder was obtained.

  Next, lithium hydroxide monohydrate was weighed so that the atomic ratio of nickel atoms to lithium atoms in the obtained nickel hydroxide was 1: 1.03. A composite oxide was obtained by thoroughly mixing with a hydroxide dry powder and firing the resulting mixture at a temperature of 750 ° C. for 10 hours in an air atmosphere. The obtained composite oxide was pulverized to obtain composite oxide particles having a particle size of 20 μm or less.

The obtained composite oxide particles had a space group Fd3m type structure and were represented by the formula: LiNi _1.00 O _2.00 . Hereinafter, the composite oxide particles are referred to as composite oxide particles F.

Production Example 7 (Production of composite oxide particles G)
In a 15 L cylindrical reactor equipped with a stirrer and overflow pipe, 13 L of water was added, and then 30% aqueous sodium hydroxide solution was added until the pH reached 10.9, and the liquid temperature was maintained at 50 ° C. Then, nitrogen gas was blown into this aqueous solution at a flow rate of 0.5 L / min, and stirring was performed while removing dissolved oxygen.

  On the other hand, a 1 mol / L manganese sulfate aqueous solution was prepared, and a 6 mol / L ammonium sulfate aqueous solution was added at a rate of 50 mL per 1 L of the solution. In order to remove dissolved oxygen in the mixed solution, a 4% by mass hydrazine aqueous solution was added at a rate of 13 mL per liter of the mixed solution to prepare a mixed raw material solution.

  Next, this mixed raw material solution is continuously added to the cylindrical reaction vessel at a flow rate of 10 mL / min, and 30% sodium hydroxide is added so that the pH of the solution in the reaction vessel becomes 10.9. The manganese hydroxide particles were obtained by intermittent addition.

  After the reaction vessel is in a steady state, manganese hydroxide particles are continuously collected from the overflow pipe, washed with water, filtered, and dried at a temperature of 100 ° C. for 15 hours to dry the manganese hydroxide. A powder was obtained.

  Next, lithium hydroxide monohydrate was weighed so that the atomic ratio of lithium atoms to manganese atoms in the obtained manganese hydroxide was 1: 0.52, and this lithium hydroxide monohydrate and manganese were weighed. The composite oxide was obtained by thoroughly mixing with the hydroxide dry powder and firing the resulting mixture at a temperature of 850 ° C. for 10 hours in an air atmosphere. The obtained composite oxide was pulverized to obtain composite oxide particles having a particle size of 20 μm or less.

The obtained composite oxide particles had a space group Fd3m type structure and were represented by the formula: LiMn _2.00 O _4.00 . Hereinafter, this composite oxide particle is referred to as composite oxide particle G.

Production Example 8 (Production of composite oxide particles H)
In a 15 L cylindrical reactor equipped with a stirrer and an overflow pipe, 13 L of water was added, and then a 30% aqueous sodium hydroxide solution was added until the pH reached 11.4, and the liquid temperature was maintained at 50 ° C. Then, nitrogen gas was blown into this aqueous solution at a flow rate of 0.5 L / min to perform stirring while removing dissolved oxygen.

  On the other hand, a 1.7 mol / L nickel sulfate aqueous solution and a 1 mol / L manganese sulfate aqueous solution were mixed so that the atomic ratio of nickel atoms to manganese atoms was 0.5: 1.5. A 6 mol / L ammonium sulfate aqueous solution was added at a rate of 50 mL per 1 L of the mixed solution. In order to remove dissolved oxygen in the mixed solution, a 4% by mass hydrazine aqueous solution was added at a rate of 13 mL per liter of the mixed solution to prepare a mixed raw material solution.

  Next, this mixed raw material solution is continuously added to the cylindrical reaction vessel at a flow rate of 10 mL / min, and 30% sodium hydroxide is added so that the pH of the solution in the reaction vessel becomes 11.4. The nickel-manganese composite hydroxide particles were obtained by intermittent addition.

  After the reaction vessel is in a steady state, nickel-manganese composite hydroxide particles are continuously collected from the overflow pipe, washed with water, filtered, and dried at a temperature of 100 ° C. for 15 hours. A dry powder of composite hydroxide was obtained.

  Next, lithium hydroxide monohydrate was weighed so that the atomic ratio of the total amount of nickel atoms and manganese atoms and lithium atoms in the obtained nickel-manganese composite hydroxide was 1: 0.52. The lithium hydroxide monohydrate and the dry powder of nickel-manganese composite hydroxide were mixed thoroughly, and the resulting mixture was calcined at 1000 ° C. for 10 hours in an air atmosphere to obtain composite oxidation. I got a thing. The obtained composite oxide was pulverized to obtain composite oxide particles having a particle size of 20 μm or less.

The obtained composite oxide particles have an atomic ratio of nickel atoms to manganese atoms of 0.5: 1.5, a space group Fd3m type structure, and a formula: LiNi _0.50 Mn _1.50 O _4. It was represented by ₀₀ . Hereinafter, the composite oxide particles are referred to as composite oxide particles H.

Production Example 9 (Production of Composite Oxide Particle I)
In a 15 L cylindrical reactor equipped with a stirrer and overflow pipe, 13 L of water was added, and then 30% aqueous sodium hydroxide solution was added until the pH reached 10.9, and the liquid temperature was maintained at 50 ° C. Then, nitrogen gas was blown into this aqueous solution at a flow rate of 0.5 L / min to perform stirring while removing dissolved oxygen.

  On the other hand, a 1.7 mol / L nickel sulfate aqueous solution, a 1.5 mol / L cobalt sulfate aqueous solution and a 1.1 mol / L manganese sulfate aqueous solution have an atomic ratio of nickel atom, cobalt atom and manganese atom of 0.3: 0.3: It mixed so that it might become 1.4. A 6 mol / L ammonium sulfate aqueous solution was added at a rate of 50 mL per 1 L of the mixed solution. In order to remove dissolved oxygen in the mixed solution, a 4% by mass hydrazine aqueous solution was added at a rate of 13 mL per liter of the mixed solution to prepare a mixed raw material solution.

  Next, this mixed raw material solution is continuously added to the cylindrical reaction vessel at a flow rate of 10 mL / min, and 30% sodium hydroxide is added so that the pH of the solution in the reaction vessel becomes 10.9. The nickel-cobalt-manganese composite hydroxide particles were obtained by intermittent addition.

  After the reaction vessel is in a steady state, nickel-cobalt-manganese composite hydroxide particles are continuously collected from the overflow pipe, washed with water, filtered, and dried at a temperature of 100 ° C. for 15 hours. -A dry powder of cobalt-manganese composite hydroxide was obtained.

  Next, lithium hydroxide monohydrate so that the atomic ratio of the total amount of nickel atoms, cobalt atoms and manganese atoms to lithium atoms in the obtained nickel-cobalt-manganese composite hydroxide is 1: 0.52. The hydrate was weighed, the lithium hydroxide monohydrate and the dry powder of nickel-cobalt-manganese composite hydroxide were thoroughly mixed, and the resulting mixture was allowed to stand at 1000 ° C. for 10 hours in the atmosphere. By firing, a composite oxide was obtained. The obtained composite oxide was pulverized to obtain composite oxide particles having a particle size of 20 μm or less.

The obtained composite oxide particles have an atomic ratio of nickel atom, cobalt atom, and manganese atom of 0.3: 0.3: 1.4, a space group Fd3m type structure, and a formula: LiNi _0.70 Co It was represented by _0.30 Mn _1.00 O _4.00 . Hereinafter, the composite oxide particles are referred to as composite oxide particles I.

Production Example 10 (Production of composite oxide particle J)
In a 15 L cylindrical reactor equipped with a stirrer and overflow pipe, 13 L of water was added, and then 30% aqueous sodium hydroxide solution was added until the pH reached 10.9, and the liquid temperature was maintained at 50 ° C. Then, nitrogen gas was blown into this aqueous solution at a flow rate of 0.5 L / min to perform stirring while removing dissolved oxygen.

  On the other hand, a 1.5 mol / L cobalt sulfate aqueous solution and a 1.1 mol / L manganese sulfate aqueous solution were mixed so that the atomic ratio of cobalt atoms to manganese atoms was 1: 9. A 6 mol / L ammonium sulfate aqueous solution was added at a rate of 50 mL per 1 L of the mixed solution. In order to remove dissolved oxygen in the mixed solution, a 4% by mass hydrazine aqueous solution was added at a rate of 13 mL per liter of the mixed solution to prepare a mixed raw material solution.

  Next, this mixed raw material solution is continuously added to the cylindrical reaction vessel at a flow rate of 10 mL / min, and 30% sodium hydroxide is added so that the pH of the solution in the reaction vessel becomes 10.9. By intermittently adding, cobalt-manganese composite hydroxide particles were obtained.

  After the reaction vessel is in a steady state, cobalt-manganese composite hydroxide particles are continuously collected from the overflow pipe, washed with water, filtered, and dried at a temperature of 100 ° C. for 15 hours to obtain cobalt-manganese. A dry powder of composite hydroxide was obtained.

  Next, the lithium hydroxide monohydrate was weighed so that the total amount of cobalt atoms and manganese atoms of the obtained cobalt-manganese composite hydroxide and the atomic ratio of lithium atoms was 1: 0.52. The lithium hydroxide monohydrate and the dry powder of the cobalt-manganese composite hydroxide are sufficiently mixed, and the resulting mixture is fired at a temperature of 1000 ° C. for 10 hours in an air atmosphere to obtain a composite oxide. Got. The obtained composite oxide was pulverized to obtain composite oxide particles having a particle size of 20 μm or less.

The obtained composite oxide particle has an atomic ratio of cobalt atom to manganese atom of 1: 9, has a space group Fd3m type structure, and is represented by the formula: LiCo _0.20 Mn _1.80 O _2.00. It was something. Hereinafter, the composite oxide particles are referred to as composite oxide particles J.

Production Example 11 (Production of composite oxide particles K)
In a 15 L cylindrical reactor equipped with a stirrer and overflow pipe, 13 L of water was added, and then 30% aqueous sodium hydroxide solution was added until the pH reached 10.9, and the liquid temperature was maintained at 50 ° C. Then, stirring was performed while nitrogen gas was blown into the aqueous solution at a flow rate of 0.5 L / min to remove dissolved oxygen.

  On the other hand, a 1.7 mol / L nickel sulfate aqueous solution and a 1.5 mol / L cobalt sulfate aqueous solution were mixed so that the atomic ratio of nickel atoms to cobalt atoms was 0.75: 0.25. A 6 mol / L ammonium sulfate aqueous solution was added to the obtained mixed solution at a rate of 50 mL per 1 L of the mixed solution. In order to remove dissolved oxygen in the mixed solution, a 4% by mass hydrazine aqueous solution was added to the mixed solution at a rate of 13 mL per liter of the mixed solution to prepare a mixed raw material solution.

  Next, this mixed raw material solution is continuously added to the cylindrical reaction vessel at a flow rate of 10 mL / min, and 30% sodium hydroxide is added so that the pH of the solution in the reaction vessel becomes 10.9. The nickel-cobalt composite hydroxide particles were obtained by intermittent addition.

  After the reaction vessel is in a steady state, nickel-cobalt composite hydroxide particles are continuously collected from the overflow pipe, washed with water, filtered, and dried at a temperature of 100 ° C. for 15 hours. A dry powder of composite hydroxide was obtained.

  Next, lithium hydroxide monohydrate was weighed so that the total amount of nickel atoms and cobalt atoms in the obtained nickel-cobalt composite hydroxide and the atomic ratio of lithium atoms was 1: 1.03. The lithium hydroxide monohydrate and the dry powder of nickel-cobalt composite hydroxide were thoroughly mixed, and the resulting mixture was calcined at 750 ° C. for 10 hours in the air atmosphere to obtain composite oxidation. I got a thing. The obtained composite oxide was pulverized to obtain composite oxide particles having a particle size of 20 μm or less.

The obtained composite oxide particles have an atomic ratio of nickel atom to cobalt atom of 0.75: 0.25, a space group R-3m type structure, and a formula: LiNi _0.75 Co _0.25 O. It was represented by _2.00 . Hereinafter, the composite oxide particles are referred to as composite oxide particles K.

Production Example 12 (Production of composite oxide particles L)
In a 15 L cylindrical reactor equipped with a stirrer and overflow pipe, 13 L of water was added, and then 30% aqueous sodium hydroxide solution was added until the pH reached 10.9, and the liquid temperature was maintained at 50 ° C. Then, stirring was performed while nitrogen gas was blown into the aqueous solution at a flow rate of 0.5 L / min to remove dissolved oxygen.

  On the other hand, a 1.7 mol / L nickel sulfate aqueous solution, a 1.5 mol / L cobalt sulfate aqueous solution and a 1.5 mol / L aluminum sulfate solution have an atomic ratio of nickel atoms, cobalt atoms and aluminum atoms of 0.80: 0.15: It mixed so that it might become 0.05. A 6 mol / L ammonium sulfate aqueous solution was added to the obtained mixed solution at a rate of 50 mL per 1 L of the mixed solution. In order to remove dissolved oxygen in the mixed solution, a 4% by mass hydrazine aqueous solution was added to the mixed solution at a rate of 13 mL per liter of the mixed solution to prepare a mixed raw material solution.

  Next, this mixed raw material solution is continuously added to the cylindrical reaction vessel at a flow rate of 10 mL / min, and 30% sodium hydroxide is added so that the pH of the solution in the reaction vessel becomes 10.9. The nickel-cobalt-aluminum composite hydroxide particles were obtained by intermittent addition.

  After the reaction vessel is in a steady state, nickel-cobalt-aluminum composite hydroxide particles are continuously collected from the overflow pipe, washed with water, filtered, and dried at a temperature of 100 ° C. for 15 hours. -A dry powder of cobalt-aluminum composite hydroxide was obtained.

  Next, lithium hydroxide monohydration is performed so that the total amount of nickel atoms, cobalt atoms and aluminum atoms and the atomic ratio of lithium atoms in the obtained nickel-cobalt-aluminum composite hydroxide is 1: 1.03. The lithium hydroxide monohydrate and the nickel-cobalt-aluminum composite hydroxide dry powder were thoroughly mixed, and the resulting mixture was calcined at 750 ° C. for 10 hours in the atmosphere. As a result, a composite oxide was obtained. The obtained composite oxide was pulverized to obtain composite oxide particles having a particle size of 20 μm or less.

The obtained composite oxide particles have an atomic ratio of nickel atom, cobalt atom, and aluminum of 0.80: 0.15: 0.05, and have a space group R-3m type structure _. It was represented by ₈₀ Co _0.15 Al _0.05 O _2.00 . Hereinafter, the composite oxide particles are referred to as composite oxide particles L.

Production Example 13 (Production of Composite Oxide Particle M)
In a 15 L cylindrical reactor equipped with a stirrer and overflow pipe, 13 L of water was added, and then 30% aqueous sodium hydroxide solution was added until the pH reached 10.9, and the liquid temperature was maintained at 50 ° C. Then, stirring was performed while nitrogen gas was blown into the aqueous solution at a flow rate of 0.5 L / min to remove dissolved oxygen.

  On the other hand, a 1.5 mol / L cobalt sulfate aqueous solution and a 1.0 mol / L magnesium sulfate solution were mixed so that the atomic ratio of cobalt atoms to magnesium atoms was 0.95: 0.05. A 6 mol / L ammonium sulfate aqueous solution was added to the obtained mixed solution at a rate of 50 mL per 1 L of the mixed solution. In order to remove dissolved oxygen in the mixed solution, a 4% by mass hydrazine aqueous solution was added to the mixed solution at a rate of 13 mL per liter of the mixed solution to prepare a mixed raw material solution.

  Next, this mixed raw material solution is continuously added to the cylindrical reaction vessel at a flow rate of 10 mL / min, and 30% sodium hydroxide is added so that the pH of the solution in the reaction vessel becomes 10.9. The cobalt-magnesium composite hydroxide particles were obtained by intermittent addition.

  After the reaction vessel is in a steady state, cobalt-magnesium composite hydroxide particles are continuously collected from the overflow pipe, washed with water, filtered, and dried at a temperature of 100 ° C. for 15 hours to obtain cobalt-magnesium. A dry powder of composite hydroxide was obtained.

  Next, the lithium hydroxide monohydrate was weighed so that the total amount of cobalt atoms and magnesium atoms and the atomic ratio of lithium atoms in the obtained cobalt-magnesium composite hydroxide was 1: 1.03, The lithium hydroxide monohydrate and the dry powder of the cobalt-magnesium composite hydroxide are sufficiently mixed, and the resulting mixture is fired at 900 ° C. for 10 hours in the air atmosphere to obtain a composite oxide. Got. The obtained composite oxide was pulverized to obtain composite oxide particles having a particle size of 20 μm or less.

The obtained composite oxide particles have an atomic ratio of cobalt atom to magnesium of 0.95: 0.05, a space group R-3m type structure, and a formula: LiCo _0.95 Mg _0.05 O _2. It was represented by _.00 . Hereinafter, the composite oxide particles are referred to as composite oxide particles M.

Example 1
20 g of the composite oxide particles A obtained in Production Example 1 were placed in an agate mortar, and 0.2 g of liquid ethyl diethylphosphonoacetate was added to the agate mortar little by little using a micropipette while stirring with a spatula. After completion of the addition of ethyl diethylphosphonoacetate, the resulting mixture was further stirred with a spatula and a pestle for 20 minutes to uniformly adhere ethyldiethylphosphonoacetate to the composite oxide particles.

  Next, the composite oxide particles having the ethyl diethylphosphonoacetate attached thereto are transferred into a stainless steel sealed container, the temperature in the container is adjusted to 50 ° C., the pressure is reduced to 600 Pa with a vacuum pump, and the vacuum is maintained for 1 hour. By drying, mixed water was removed, and a positive electrode material was obtained. The obtained positive electrode material was stored in a container filled with argon gas.

Examples 2-10
A positive electrode material was obtained in the same manner as in Example 1, except that the type of phosphonate compound in Example 1 was changed as shown in Table 1. The obtained positive electrode material was stored in a container filled with argon gas.

Example 11
By adding 0.2 g of ethyl diethylphosphonoacetate and 1.8 g of acetone to the test tube and stirring sufficiently, ethyldiethylphosphonoacetate was completely dissolved to obtain an acetone solution of ethyldiethylphosphonoacetate.

  20 g of the composite oxide particles A obtained in Production Example 1 were placed in an agate mortar, and the acetone solution of ethyl diethylphosphonoacetate obtained above was added little by little to the agate mortar using a micropipette while stirring with a spatula. . After completion of the addition of the ethyldiethylphosphonoacetate solution in acetone, the resulting mixture was further stirred with a spatula and a pestle for 20 minutes to uniformly adhere the ethyldiethylphosphonoacetate to the composite oxide particles.

  Next, the composite oxide particles having the ethyl diethylphosphonoacetate attached thereto are transferred into a stainless steel sealed container, the temperature in the container is adjusted to 50 ° C., the pressure is reduced to 600 Pa with a vacuum pump, and the vacuum is maintained for 1 hour. By drying, acetone and mixed water were removed, and a positive electrode material was obtained. The obtained positive electrode material was stored in a container filled with argon gas.

Examples 12-20
In Example 11, instead of the ethyldiethylphosphonoacetate solution in acetone, the type of phosphonate compound was changed as shown in Table 1, and 0.2 g of phosphonate compound and 1.8 g of acetone were added to the test tube. A positive electrode material was obtained in the same manner as in Example 11 except that a solution in which the phosphonate compound was completely dissolved by stirring was used. The obtained positive electrode material was stored in a container filled with argon gas.

Examples 21-32
In Example 11, a positive electrode material was obtained in the same manner as in Example 11 except that the types of the composite oxide and the phosphonate compound were changed as shown in Table 2. The obtained positive electrode material was stored in a container filled with argon gas.

Examples 33-36
In Example 11, a positive electrode material was obtained in the same manner as in Example 11 except that the amount of the phosphonate compound per 100 parts by mass of the composite oxide particles was changed as shown in Table 3. The obtained positive electrode material was stored in a container filled with argon gas.

Example 37
20 g of the composite oxide particles A obtained in Production Example 1 were placed in an agate mortar, and a solution obtained by diluting 0.01 g of liquid ethyl diethylphosphonoacetate with 2 g of acetone while stirring with a spatula was gradually added to the agate mortar with a micropipette. Added. After completion of the addition of the ethyldiethylphosphonoacetate solution in acetone, the resulting mixture was further stirred with a spatula and pestle for 20 minutes to uniformly adhere the ethyldiethylphosphonoacetate to the composite oxide particles.

  Next, the composite oxide particles having the ethyl diethylphosphonoacetate adhered thereto are transferred into a stainless steel sealed container, the temperature in the container is adjusted to 50 ° C., the pressure is reduced to 600 Pa with a vacuum pump, and the vacuum is maintained for 1 hour. By drying, mixed water was removed, and a positive electrode material was obtained. The obtained positive electrode material was stored in a container filled with argon gas.

Example 38
20 g of the composite oxide particles A obtained in Production Example 1 were placed in an agate mortar, and a solution obtained by diluting 1.6 g of liquid ethyl diethylphosphonoacetate with 10 g of acetone while stirring with a spatula was gradually added to the agate mortar with a micropipette. Added. After completion of the addition of the ethyldiethylphosphonoacetate solution in acetone, the resulting mixture was further stirred with a spatula and a pestle for 20 minutes to uniformly adhere the ethyldiethylphosphonoacetate to the composite oxide particles.

  Next, the composite oxide particles having the ethyl diethylphosphonoacetate attached thereto are transferred into a stainless steel sealed container, the temperature in the container is adjusted to 50 ° C., the pressure is reduced to 600 Pa with a vacuum pump, and the vacuum is maintained for 1 hour. By drying, mixed water was removed, and a positive electrode material was obtained. The obtained positive electrode material was stored in a container filled with argon gas.

Comparative Example 1
In Example 11, a positive electrode material was obtained in the same manner as in Example 11 except that the phosphonate compound was not used. The obtained positive electrode material was stored in a container filled with argon gas.

Comparative Example 2
In Example 11, a positive electrode material was obtained in the same manner as in Example 11 except that 0.2 g of octylphosphonic acid was used instead of 0.2 g of ethyl diethylphosphonoacetate. The obtained positive electrode material was stored in a container filled with argon gas.

Comparative Example 3
In Example 11, a positive electrode material was obtained in the same manner as in Example 11 except that 0.2 g of trimethyl phosphate was used instead of 0.2 g of ethyl diethylphosphonoacetate. The obtained positive electrode material was stored in a container filled with argon gas.

  Table 4 shows the compositions of the positive electrode materials obtained in Examples 37 to 38 and Comparative Examples 1 to 3.

Experimental Example 1 (Confirmation of presence of phosphonate compound on the surface of the positive electrode material)
Whether the phosphonate compound was present on the surface of the positive electrode material obtained in each example was examined by the following method.

(1) Measurement of infrared spectroscopic analysis (IR) spectrum The presence of a phosphonate compound on the surface of each positive electrode material is red using an infrared spectroscopic analyzer [manufactured by JASCO Corporation, product number: FT / IR-460Plus]. It confirmed by investigating the absorption peak of the stretching vibration originating in the PO bond of an external spectroscopy (IR) spectrum.

As an example, the IR spectrum of the positive electrode material obtained in Example 12 is shown in FIG. Since the positive electrode material is hard and granular, its measurement sensitivity is low, but as shown in FIG. 1, the absorption peak of the stretching vibration derived from the P—O—C bond is clearly observed in the vicinity of 1050 cm ^−1. Has been. From this, it can be seen that, in the positive electrode material obtained in Example 12, the phosphonate compound is adhered to the composite oxide particles.

(2) Measurement of conductivity The conductivity of the positive electrode materials obtained in Examples 1 to 20 was measured with a powder conductivity measurement device [manufactured by Dia Instruments Co., Ltd., powder resistance measurement system, model number: MCP-PD51]. As a result, while it was 10 ⁻³ Scm ⁻¹ , the conductivity of the positive electrode material obtained in Example 38 was 10 ⁻⁵ to 10 ⁻⁴ Scm ⁻¹ . From this, it is presumed that the positive electrode material obtained in Example 38 has a high possibility that the surface is almost completely covered with the phosphonate compound.

Experimental Example 2 (Analysis of crystal structure of positive electrode material)
The composite oxide particles A, the positive electrode material obtained in Example 1, the positive electrode material obtained in Example 11 and the positive electrode material obtained in Example 12 were each characterized by copper characteristic X-rays (wavelength 1.54 mm). X-ray diffraction was performed by scanning at 2 ° per minute within a range of 2θ of 10 to 85 °. For measurement of X-ray diffraction, product number: XD-3A manufactured by Shimadzu Corporation was used. The result is shown in FIG.

  2, 1 is X-ray diffraction of the composite oxide particle A, 2 is X-ray diffraction of the positive electrode material obtained in Example 1, 3 is X-ray diffraction of the positive electrode material obtained in Example 11, and 4 is The X-ray diffraction of the positive electrode material obtained in Example 12 is shown.

  From the results shown in FIG. 2, the change in the pattern of X-ray diffraction caused by attaching the phosphonate compound to the surface of the composite oxide particle A is within the range of experimental error, and hardly changes by the attachment treatment of the phosphonate compound. This shows that the phosphonate compound exists only on the surface of the composite oxide particle and does not affect the crystal structure of the composite oxide particle A.

Experimental Example 3 (Measurement of specific surface area)
The specific surface areas of the positive electrode materials obtained in the composite oxide particles A (Comparative Example 1), Example 1 and Examples 11 to 15 were examined by the following method. The results are shown in Table 5.

〔Specific surface area〕
It calculated | required from the nitrogen gas adsorption amount measured using the micromeritics (Micromeritics) company make and product number: ASAP2100.

  From the results shown in Table 5, it can be seen that the specific surface area of the positive electrode material obtained in each example hardly changes depending on the type of the phosphonate compound. This shows that the phosphonate compound exists only on the surface without changing the surface morphology of the composite oxide particles.

Experimental Example 4 (Measurement of physical properties of positive electrode material)
The physical properties of the positive electrode materials obtained in Examples 11 to 32 were measured based on the following methods.

  Each component is mixed at a ratio of 3 parts by mass of acetylene black as a conductive agent and 5 parts by mass of polyvinylidene fluoride as a binder per 100 parts by mass of the composite oxide particles to which the phosphonate compound as an active material is adhered. The resulting mixture was further mixed in N-methyl-2-pyrrolidone as an organic solvent, and the paste obtained by dispersing was applied to an aluminum current collector sheet, dried and rolled to obtain a positive electrode plate. .

  Using graphite as an active material for the negative electrode, a copper current collector was obtained by kneading and dispersing both in water at a ratio of 2.5 parts by mass of styrene butadiene rubber as a binder per 100 parts by mass of graphite. The negative electrode plate was obtained by coating on a body sheet, drying and rolling.

  A battery was prepared in which the capacity ratio between the positive electrode plate and the negative electrode plate was adjusted in advance so that a capacity of about 100 mAh was obtained. More specifically, a laminate cell 3 formed of an aluminum foil shown in FIG. 3 was used. FIG. 3 is a schematic explanatory view of a laminate cell 3 formed of aluminum foil.

In FIG. 3, a positive electrode plate 1 as a test electrode and a negative electrode plate 2 as a counter electrode are opposed to each other via a separator (not shown). The laminate cell 3 formed of aluminum foil is impregnated with an electrolyte solution in which LiPF ₆ is dissolved in a mixed solvent of ethylene carbonate and diethyl carbonate in an amount of 1 mol / dm ³ by vacuum injection. (Not shown) is sealed. The laminate cell 3 is provided with a battery operation chamber 4 in which the positive electrode plate 1 and the negative electrode plate 2 exist, and a gas reservoir chamber 5 for collecting a gas generated by a side reaction. A gas passage 6 is formed in a partition wall (not shown) of the reservoir chamber 5.

  The electrochemical oxidation treatment was completed by applying an electrochemical oxidation current of 10 mA to the positive electrode plate 1 at room temperature and terminating the current supply when the voltage of the laminate cell 3 reached 4.0V.

  The laminated cell 3 after the electrochemical oxidation treatment was left at 45 ° C. for 1 hour or longer, and then discharged at a discharge current of 10 mA until the potential reached 3.0V.

  Next, after the obtained laminate cell 3 was charged to 4.5 V in the atmosphere at 45 ° C., it was stored in an open circuit state for 3 days to collect the generated gas. Further, the laminate cell 3 was disassembled after the test was completed, and the amount of transition metal element present in the electrolytic solution and the negative electrode plate 2 was analyzed. As a result, a gas derived from the positive electrode plate 1 mainly containing carbon dioxide gas and a gas derived from the negative electrode plate 2 mainly containing methane gas were detected. Among these, since the gas derived from the positive electrode plate 1 is considered to be a component mainly generated by a side reaction between the positive electrode plate 1 and the electrolytic solution, the gas derived from the positive electrode plate 1 depending on the presence or absence of the adhesion treatment of the phosphonate compound. The amount generated was examined.

  The transition metal element present in the electrolyte and the negative electrode plate 2 is a component mainly eluted from the positive electrode plate 1 and serves as an index indicating the stability of the positive electrode plate 1. The smaller the amount of transition metal element eluted, the more stable the positive electrode plate 1. it seems to do.

  Using the obtained laminate cell 3, the gas generation ratio, the eluted metal ion ratio and the volume ratio were examined based on the following methods. The results are shown in Table 6.

[Gas generation ratio]
In order to confirm the effect of the adhesion treatment of the phosphonate compound on the composite oxide having the space group R-3m type structure or the space group Fd3m type structure, the laminate cell 3 was used and a charging voltage of 4.5 V in an atmosphere at 45 ° C. After charging, the gas generated for 3 days was collected in an open circuit state, and the ratio of the total gas generation amount (the value of the ratio with / without treatment) was determined as the gas generation ratio.

  The “value of the ratio with / without treatment” is the value obtained by dividing the amount of gas generated by the adhesion treatment of the phosphonate compound by the amount of gas generated without the adhesion treatment of the phosphonate compound. Means (the same applies below).

[Eluted metal ion ratio]
In order to investigate the effect of the adhesion treatment of the phosphonate compound on the composite oxide having the space group R-3m type structure or the space group Fd3m type structure, the laminate cell 3 was used, and the charging voltage was 4.5 V in the atmosphere at 45 ° C. After charging and storing in an open circuit state for 3 days, the ratio of the amount of transition metal ions in the negative electrode (the value of the ratio with / without treatment) was determined as the ratio of eluted metal ions.

[Capacity ratio]
In order to investigate the influence of the adhesion treatment of the phosphonate compound on the composite oxide having the space group R-3m type structure or the space group Fd3m type structure on the capacity characteristics, the laminate cell 3 was used, and 4.5 V in an atmosphere at 45 ° C. The battery was charged at a charging voltage of 1 and stored in an open circuit state for 3 days, and then the ratio of the discharge capacity corresponding to 0.2 C (with / without treatment) was determined as the capacity ratio.

  From the results shown in Table 6, in any of the Examples, the gas generation ratio and the eluted metal ion ratio are small and the capacity ratio is close to 1 regardless of the difference in the crystal space group. It can be seen that even when the treatment is performed, the discharge capacity corresponding to 0.2 C is hardly affected.

Experimental Example 5 (Measurement of physical properties of positive electrode material)
For the positive electrode materials obtained in Examples 33 to 38, the gas generation ratio, eluted metal ion ratio, and capacity ratio were examined in the same manner as in Experimental Example 4. The results are shown in Table 7.

  From the results shown in Table 7, in Examples 33 to 38, the gas generation ratio and the eluted metal ion ratio were small, and the volume ratio was close to 1. Therefore, even when the adhesion treatment of the phosphonate compound was performed, the capacity was almost the same. It turns out that it is not influenced. In addition, from the result of Example 38, when the amount of the phosphonate compound per 100 parts by mass of the composite oxide particles is 8 parts by mass, the capacity ratio at the time of charging / discharging is slightly reduced, so the performance as a battery is good. It turns out that it falls a little.

Comparative Examples 4 and 5
In Experimental Example 4, the composite oxide particles A that were not subjected to surface treatment were used as they were, and LiPF ₆ was dissolved in a mixed solvent of ethylene carbonate and diethyl carbonate to be injected into the laminate cell 3 in an amount of 1 mol / dm ³ . A solution in which trimethyl phosphate is dissolved in an electrolytic solution so that the concentration of trimethyl phosphate is 3% by volume (Comparative Example 4), and ethyl diethylphosphonoacetate is adjusted so that the concentration of ethyl diethylphosphonoacetate is 3% by volume. A laminate cell was prepared in the same manner as in Experimental Example 4 except that an acetate dissolved (Comparative Example 5) was used.

Experimental Example 6 (Measurement of physical properties of positive electrode material)
For the positive electrode materials obtained in Comparative Examples 2 to 5, the gas generation ratio, the eluted metal ion ratio, and the volume ratio were examined in the same manner as in Experimental Example 4. The results are shown in Table 8.

  From the results shown in Table 8, it can be seen that in “acid” such as phosphonic acid, the ratio of eluted metal ions is increased and the discharge capacity is decreased. Moreover, when a phosphorus containing compound is added to electrolyte solution like the comparative examples 4 and 5, it turns out that the performance as a battery falls, such as discharge capacity reducing a little.

Experimental Example 7 (Thermal stability in the charged state of composite oxide particles by DSC)
In order to investigate the thermal decomposition behavior in the charged state of the composite oxide particles having the space group R-3m type structure subjected to the adhesion treatment of the phosphonate compound, the positive electrode materials obtained in Examples 11 to 20 and Example 37 were used. In the same manner as in Experimental Example 4, the sample was placed in the laminate cell 3 shown in FIG. 3 and charged at a charging voltage of 4.5 V in an atmosphere at 45 ° C., and then the positive electrode material was taken out and sealed using a stainless steel sealed cell. The heat generation and endotherm of the positive electrode material were examined using a differential scanning calorimeter (manufactured by Seiko Instruments Inc., product number: DSC / 5200) within a temperature range from room temperature to 350 ° C. at a temperature rising rate of 10 ° C./sec. The results are shown in Table 9.

  As shown in Table 9, by attaching a phosphonate compound to a composite oxide having an R-3m type structure, the exothermic peak became broad and shifted to a high temperature side, so that the composite oxidation having an R-3m type structure was performed. It can be seen that if a phosphonate compound is attached to the product, a chemical reaction that occurs during heating on the charged composite oxide particles can be suppressed.

  In addition, from the DSC measurement result of Example 37, since the peak temperature is 300 ° C., it can be seen that when the adhesion amount of phosphonate is less than 0.1% by mass, the effect of suppressing the chemical reaction is slightly low.

  From the above, the positive electrode material obtained by adhering the phosphonate compound to the composite oxide particles is charged with an irreversible chemical reaction different from the charge / discharge reaction that occurs during heating on the positive electrode in a charged state, that is, for the battery. It can be seen that the chemical reaction that adversely affects the discharge cycle life is suppressed.

  Next, FIG. 4 shows the DSC measurement results in the charged state of the positive electrode material to which the phosphonate compound obtained in Example 11 is attached. FIG. 4 shows the result of the positive electrode material to which the phosphonate compound obtained in Comparative Example 1 is not attached. The DSC measurement results in the charged state are shown in FIG.

  From the results shown in FIGS. 4 and 5, an exothermic peak was observed as a broad peak in the vicinity of 315 ° C. in FIG. 4, and a sharp exothermic peak observed in the vicinity of 297 ° C. was observed in FIG.

Experiment 8 (existence confirmation test of phosphonate compound after charging)
The composite oxide particles subjected to the adhesion treatment of the phosphonate compound obtained in Example 12 were subjected to the following effect confirmation test in order to confirm the presence of the phosphonate compound on the surface of the composite oxide particles after the charge treatment. .

  Using the composite oxide particles to which the phosphonate compound obtained in Example 12 was attached, a positive electrode plate was produced in the same manner as in Experimental Example 4, and this was applied to the laminate cell 3 shown in FIG. Then, after charging at a charging voltage of 4.5 V in an atmosphere of 45 ° C., this positive electrode plate was taken out, and an infrared spectroscopic analysis (IR) spectrum was measured in the same manner as in Experimental Example 1. The measurement results are shown in FIG.

In results shown in Figure 6 is different from the results shown in Figure 1, peaks around 1200 cm ^-1 and 850 cm ^-1 derived from polyvinylidene fluoride were mixed at the time of production of the negative plate is newly emerged However, since the absorption peak of stretching vibration appears clearly in the vicinity of 1050 cm ⁻¹ particularly derived from the P—O—C bond, the phosphonate compound is not decomposed even after the charge treatment. It turns out that it has adhered to the oxide particle.

  As described above, the positive electrode material for a non-aqueous electrolyte secondary battery obtained by the production method of the present invention suppresses the generation of gas and the elution of metal ions at the interface between the electrolyte and the positive electrode. Reliability and safety can be increased. In addition, since the non-aqueous electrolyte secondary battery of the present invention uses the positive electrode material for non-aqueous electrolyte secondary batteries, the electrolyte solution has reached an electrochemically oxidized state by a charging operation after the battery configuration. It can be seen that the generation of gas and the elution of metal ions at the interface between the anode and the positive electrode are suppressed, so that the reliability and safety of the battery can be improved.

6 is a graph showing the measurement results of infrared spectroscopic analysis (IR) of the positive electrode material obtained in Example 12. 1-4 are X-ray diffraction patterns of the composite oxide particles A, the positive electrode material obtained in Example 1, the positive electrode material obtained in Example 11, and the positive electrode material obtained in Example 12, respectively. . It is a schematic explanatory drawing of the lamination cell formed with the aluminum foil used in Experimental example 4. It is a graph which shows the measurement result of DSC in the charge condition of the positive electrode material which the phosphonate compound obtained in Example 11 adheres. It is a graph which shows the measurement result of DSC in the charge condition of the positive electrode material which the phosphonate compound obtained by the comparative example 1 does not adhere. It is a graph which shows the measurement result of the infrared spectroscopy analysis (IR) after the charge process of the positive electrode material to which the phosphonate compound obtained in Example 12 has adhered.

Claims (9)

It contains a lithium atom and at least one atom selected from the group consisting of a nickel atom, a cobalt atom, a manganese atom, an aluminum atom, and a magnesium atom, and has a space group R-3m type structure or a space group Fd3m type structure. Compound oxide particles and formula (I):
[Wherein R ¹ , R ² and R ³ are each independently an alkyl group having 1 to 22 carbon atoms, an aryl group having 6 to 18 carbon atoms, an aralkyl group having 7 to 18 carbon atoms, a formula: —R ^{A group represented by 4-} C (O) —O—R ⁵ (wherein R ⁴ represents an alkylene group having 1 to 6 carbon atoms, R ⁵ represents an alkyl group having 1 to 6 carbon atoms), a vinyl group, A vinylalkyl group having 3 to 10 carbon atoms, a vinylaryl group having 8 to 20 carbon atoms, or a vinylarylalkyl group having 9 to 21 carbon atoms.
The positive electrode material for nonaqueous electrolyte secondary batteries characterized by including the phosphonate compound represented by these. The composite oxide particles have the formula (II):
LiM _x O _y (II)
[Wherein, M is at least one atom selected from the group consisting of nickel atom, cobalt atom, manganese atom, aluminum atom and magnesium atom, x is a number of 0.8 to 2.3, and y is 1.7. Represents a number of ˜4.5, and x and y satisfy the formula: 1 + xn = 2y (where n represents the average oxidation number of the atom M and x and y are the same as above))
The positive electrode material according to claim 1, wherein the positive electrode material is a composite oxide particle having a space group R-3m type structure or a space group Fd3m type structure.   The phosphonate compound is dimethyl methyl phosphonate, dimethyl ethyl phosphonate, dipropyl methyl phosphonate, dibutyl methyl phosphonate, diphenyl methyl phosphonate, dibenzyl methyl phosphonate, dimethyl vinyl phosphonate, diethyl vinyl phosphonate, dimethyl octadecyl phosphonate, dimethyl benzyl phosphonate, diethyl benzyl phosphonate, 3. The positive electrode material according to claim 1, wherein the positive electrode material is at least one phosphonate compound selected from the group consisting of ethyl diethylphosphonoacetate, dimethylphenylphosphonate, dimethyloctylphosphonate and dimethyl (diphenylmethyl) phosphonate.   The positive electrode material according to claim 1, wherein the amount of the phosphonate compound is 0.1 to 5 parts by mass per 100 parts by mass of the composite oxide particles.   A nonaqueous electrolyte secondary battery comprising a positive electrode, a negative electrode, a separator, and an electrolyte containing the positive electrode material for a nonaqueous electrolyte secondary battery according to claim 1. It contains a lithium atom and at least one atom selected from the group consisting of a nickel atom, a cobalt atom, a manganese atom, an aluminum atom, and a magnesium atom, and has a space group R-3m type structure or a space group Fd3m type structure. In the composite oxide particles, the formula (I):
[Wherein R ¹ , R ² and R ³ are each independently an alkyl group having 1 to 22 carbon atoms, an aryl group having 6 to 18 carbon atoms, an aralkyl group having 7 to 18 carbon atoms, a formula: —R ^{A group represented by 4-} C (O) —O—R ⁵ (wherein R ⁴ represents an alkylene group having 1 to 6 carbon atoms, R ⁵ represents an alkyl group having 1 to 6 carbon atoms), a vinyl group, A vinylalkyl group having 3 to 10 carbon atoms, a vinylaryl group having 8 to 20 carbon atoms, or a vinylarylalkyl group having 9 to 21 carbon atoms.
A method for producing a positive electrode material for a non-aqueous electrolyte secondary battery, comprising: attaching a phosphonate compound represented by: The composite oxide particles have the formula (II):
LiM _x O _y (II)
[Wherein, M is at least one atom selected from the group consisting of nickel atom, cobalt atom, manganese atom, aluminum atom and magnesium atom, x is a number of 0.8 to 2.3, and y is 1.7. Represents a number of ˜4.5, and x and y satisfy the formula: 1 + xn = 2y (where n represents the average oxidation number of the atom M and x and y are the same as above))
The method for producing a positive electrode material according to claim 6, which is a composite oxide particle having a space group R-3m type structure or a space group Fd3m type structure.   The phosphonate compound is dimethyl methyl phosphonate, dimethyl ethyl phosphonate, dipropyl methyl phosphonate, dibutyl methyl phosphonate, diphenyl methyl phosphonate, dibenzyl methyl phosphonate, dimethyl vinyl phosphonate, diethyl vinyl phosphonate, dimethyl octadecyl phosphonate, dimethyl benzyl phosphonate, diethyl benzyl phosphonate, The method for producing a positive electrode material according to claim 6 or 7, which is at least one phosphonate compound selected from the group consisting of ethyl diethylphosphonoacetate, dimethylphenylphosphonate, dimethyloctylphosphonate and dimethyl (diphenylmethyl) phosphonate.   A test electrode was constructed using composite oxide particles to which a phosphonate compound was adhered, a negative electrode made of a carbon material was used as the counter electrode of the test electrode, and electrical equipment was constructed between the test electrode and the negative electrode via an electrolyte and a separator. 9. The method for producing a positive electrode material according to claim 6, wherein an electrochemical oxidation treatment is applied to the composite oxide particles to which the phosphonate compound is adhered by applying an oxidation current to the test electrode.