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EP-4738469-A1 - POSITIVE ELECTRODE ACTIVE MATERIAL FOR LITHIUM ION BATTERIES, POSITIVE ELECTRODE FOR LITHIUM ION BATTERIES, LITHIUM ION BATTERY, METHOD FOR PRODUCING PRECURSOR OF POSITIVE ELECTRODE ACTIVE MATERIAL FOR LITHIUM ION BATTERIES, AND METHOD FOR PRODUCING POSITIVE ELECTRODE ACTIVE MATERIAL FOR LITHIUM ION BATTERIES

EP4738469A1EP 4738469 A1EP4738469 A1EP 4738469A1EP-4738469-A1

Abstract

To provide a positive electrode active material for lithium ion batteries that contains Ca and exhibits good battery characteristics, a positive electrode for lithium ion batteries, a lithium ion battery, a method for producing a precursor of a positive electrode active material for lithium ion batteries, and a method for producing a positive electrode active material for lithium ion batteries. A positive electrode active material for lithium ion batteries, having a composition represented by the formula: Li a Ni (1-b-c-d) CO b Mn c Ca d O 2 (wherein, 0.98≦a≦1.09, 0.06≦b≦0.21, 0.02≦c≦0.32, and 0.000002≦d≦0.0007), a 50% cumulative volume particle size D50 of 3.0 to 11.0 µm, a tap density of 2.0 to 2.6 g/cc, and a c-axis lattice constant of 14.180 to 14.255 Å.

Inventors

  • KAWAHASHI,YASUHIRO

Assignees

  • JX Advanced Metals Corporation

Dates

Publication Date
20260506
Application Date
20240610

Claims (6)

  1. A positive electrode active material for lithium ion batteries, having a composition represented by the formula: Li a Ni (1-b-c-d) CO b Mn c Ca d O 2 (wherein, 0.98≦a≦1.09, 0.06≦b≦0.21, 0.02≦c≦0.32, and 0.000002≦d≦0.0007), a 50% cumulative volume particle size D50 of 3.0 to 11.0 µm, a tap density of 2.0 to 2.6 g/cc, and a c-axis lattice constant of 14.180 to 14.255 Å.
  2. The positive electrode active material for lithium ion batteries according to claim 1, having a BET specific surface area of 0.20 to 0.80 m 2 /g.
  3. A positive electrode for lithium ion batteries, comprising the positive electrode active material for lithium ion batteries according to claim 1 or 2.
  4. A lithium ion battery comprising the positive electrode for lithium ion batteries according to claim 3 and a negative electrode.
  5. A method for producing a precursor of a positive electrode active material for lithium ion batteries, wherein the precursor is represented by the composition formula: Ni (1-b-c-d) CO b Mn c Ca d (OH) 2 (In the formula, 0.06≦b≦0.21, 0.02≦c≦0.32, and 0.00001≦d≦0.0007), the precursor has a 50% cumulative volume particle size D50 of 3.0 to 11.0 µm, a tap density of 1.8 to 2.4 g/cc, and a BET specific surface area of 4.0 to 12.0 m 2 /g, and the method comprises: using an aqueous solution containing (a) a nickel salt, (b) a cobalt salt, (c) a manganese salt, and (d) a calcium salt, and (e) a basic aqueous solution containing ammonia and/or a basic aqueous solution of an alkali metal as a reaction solution, and conducting a crystallization reaction while controlling a pH of the reaction solution at 10.0 to 11.5, an ammonium ion concentration at 7 to 20 g/L, and a solution temperature at 59 to 61° C.
  6. A method for producing a positive electrode active material for lithium ion batteries, comprising: mixing a precursor produced by the method for producing the precursor of the positive electrode active material for lithium ion batteries according to claim 5 with a lithium source so that the ratio (Li n /Me n ) of the number of lithium atoms (Li n ) to the sum of the numbers of atoms of metals consisting of Ni, Co, and Mn (Me n ) is 0.98 to 1.09 to form a lithium mixture; and firing the lithium mixture in air or an oxygen atmosphere at 450 to 750°C for 2 to 15 hours, and then further firing it at 700 to 900°C for 2 to 15 hours.

Description

FIELD OF THE INVENTION The present invention relates to a positive electrode active material for lithium ion batteries, a positive electrode for lithium ion batteries, a lithium ion battery, a method for producing a precursor of a positive electrode active material for lithium ion batteries and a method for producing a positive electrode active material for lithium ion batteries. BACKGROUND OF THE INVENTION In recent years, with the rapid spread of small electronic devices such as mobile phones and laptops, the demand for non-aqueous electrolyte secondary batteries as rechargeable power sources has been growing rapidly. As the positive electrode active material for non-aqueous electrolyte secondary batteries, lithiumcobalt composite oxides such as lithium cobalt oxide (LiCoO2), lithium-nickel composite oxides such as lithium nickel oxide (LiNiO2), and lithium-manganese composite oxides such as lithium manganese oxide (LiMnO2) are widely used. However, nickel and cobalt are relatively expensive metals, and cobalt in particular is known to be a metal with unstable supply and demand due to the limited number of countries where it is produced. Therefore, in recent years, as disclosed in Patent Literature 1, attempts have been made to recover metal components such as lithium, nickel, and cobalt at high purity from discarded electrodes and discarded batteries and recycle them into positive electrode active materials. CITATION LIST Patent Literatures [Patent Literature 1] Japanese Unexamined Patent Application Publication No. 2022-532575[Patent Literature 2] Japanese Unexamined Patent Application Publication No. 11-354118 SUMMARY OF THE INVENTION Although the demand for positive electrode active materials for lithium ion secondary batteries is increasing, there is a problem in that excellent positive electrode active materials have variations in cycle performance and storage stability depending on the purity of the synthetic raw materials and the refining conditions. For this reason, as disclosed in Patent Literature 2, it is necessary to control the purity of the positive electrode active material. Discarded electrodes and batteries contain various metals in the can bodies and flame-retardant materials used to prevent fire. Recovering high-purity nickel, cobalt, and lithium requires significant refining costs, resulting in high production costs for the positive electrode active material. Calcium (Ca) is particularly difficult to purify and extract, and its complete removal requires significant recycling costs. As such, while it is desirable to eliminate impurities like Ca from the perspective of controlling the purity of the positive electrode active material and improving battery performance, the cost of removing Ca poses a problem when recycling waste electrodes and batteries to recover high-purity nickel, cobalt, and lithium. The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a positive electrode active material for lithium ion batteries that contains Ca and exhibits good battery characteristics, a positive electrode for lithium ion batteries, a lithium ion battery, a method for producing a precursor of a positive electrode active material for lithium ion batteries, and a method for producing a positive electrode active material for lithium ion batteries. The present invention, which has been completed based on the above findings, is defined below. [1] A positive electrode active material for lithium ion batteries, having a composition represented by the formula: LiaNi(1-b-c-d)CObMncCadO2 (wherein, 0.98≦a≦1.09, 0.06≦b≦0.21, 0.02≦c≦0.32, and 0.000002≦d≦0.0007), a 50% cumulative volume particle size D50 of 3.0 to 11.0 µm, a tap density of 2.0 to 2.6 g/cc, and a c-axis lattice constant of 14.180 to 14.255 Å.[2] The positive electrode active material for lithium ion batteries according to [1], having a BET specific surface area of 0.20 to 0.80 m2/g.[3] A positive electrode for lithium ion batteries, comprising the positive electrode active material for lithium ion batteries according to [1] or [2].[4] A lithium ion battery comprising the positive electrode for lithium ion batteries according to [3] and a negative electrode.[5] A method for producing a precursor of a positive electrode active material for lithium ion batteries, wherein the precursor is represented by the composition formula: Ni(1-b-c-d)CObMncCad(OH)2 (In the formula, 0.06≦b≦0.21, 0.02≦c≦0.32, and 0.00001≦d≦0.0007),the precursor has a 50% cumulative volume particle size D50 of 3.0 to 11.0 µm, a tap density of 1.8 to 2.4 g/cc, and a BET specific surface area of 4.0 to 12.0 m2/g, andthe method comprises: using an aqueous solution containing (a) a nickel salt, (b) a cobalt salt, (c) a manganese salt, and (d) a calcium salt, and (e) a basic aqueous solution containing ammonia and/or a basic aqueous solution of an alkali metal as a reaction solution, and conducting a crystalliza