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JP-7857511-B1 - Lithium-ion rechargeable battery

JP7857511B1JP 7857511 B1JP7857511 B1JP 7857511B1JP-7857511-B1

Abstract

[Problem] To provide a cathode active material with high capacity and good cycle characteristics. [Solution] The positive electrode active material is designed to show little change in its crystal structure between the charging and discharging states. For example, a positive electrode active material that has a layered rock salt-type crystal structure in the discharged state and a pseudo-spinel-type crystal structure when charged at a high voltage of about 4.6V exhibits less change in crystal structure and volume before and after charging and discharging than known positive electrode active materials. When this pseudo-spinel-type crystal structure is analyzed by XRD, 2θ = 19.30 ± 0.20° and 2θ = 45.55 ± 0 A diffraction peak occurs at 10°. [Selection Diagram] Figure 1

Inventors

  • 三上 真弓
  • 内田 彩
  • 米田 祐美子
  • 門馬 洋平
  • 高橋 正弘
  • 落合 輝明

Assignees

  • 株式会社半導体エネルギー研究所

Dates

Publication Date
20260512
Application Date
20260219
Priority Date
20170519

Claims (8)

  1. A lithium-ion secondary battery having a positive electrode and a negative electrode, The positive electrode has a positive electrode active material containing cobalt, oxygen, magnesium, fluorine, and titanium. The positive electrode active material contains lithium cobalt oxide, When the positive electrode was subjected to XRD measurement under the following XRD measurement conditions, the XRD pattern due to the CuKα1 line showed diffraction peaks indicating a pseudo-spinel type crystal structure at 2θ = 19.30 ± 0.20° and 2θ = 45.55 ± 0.10°. In the range of 19° to 20° of the XRD pattern, the maximum intensity of the diffraction peak indicating the pseudo-spinel crystal structure is greater than the maximum intensity of the diffraction peak indicating the H1-3 crystal structure, and in the range of 43.5° to 46° of the XRD pattern, the maximum intensity of the diffraction peak indicating the pseudo-spinel crystal structure is greater than the maximum intensity of the diffraction peak indicating the H1-3 crystal structure. Lithium-ion rechargeable battery. XRD measurement conditions: A CR2032 type coin cell is fabricated using the above-mentioned positive electrode, lithium metal as the counter electrode, 1 mol/L lithium hexafluoride phosphate as the electrolyte of the electrolyte solution, a mixture of ethylene carbonate (EC) and diethyl carbonate (DEC) in a volume ratio of EC:DEC = 3:7 and vinylene carbonate (VC) at 2 wt%, polypropylene as the separator, and stainless steel for the positive and negative electrode cans. The fabricated coin cell is charged at a constant current of 0.5C (1C is the current value per positive electrode active material, which is 137 mA/g) to 4.6V in a 25°C environment, then charged at a constant voltage until the current value becomes 0.01C, the coin cell after constant voltage charging is disassembled in an argon atmosphere to remove the positive electrode, the positive electrode is washed with dimethyl carbonate, and then the positive electrode is measured by XRD.
  2. A lithium-ion secondary battery having a positive electrode and a negative electrode, The positive electrode has a positive electrode active material containing cobalt, oxygen, magnesium, fluorine, and titanium. The positive electrode active material contains lithium cobalt oxide, When the positive electrode was subjected to XRD measurement under the following XRD measurement conditions, the XRD pattern due to the CuKα1 line showed diffraction peaks indicating a pseudo-spinel type crystal structure at 2θ = 19.30 ± 0.20° and 2θ = 45.55 ± 0.10°. Among the diffraction peaks observed in the range of 19° to 20° of the XRD pattern, the maximum intensity of the diffraction peak indicating the pseudo-spinel crystal structure is the largest, and among the diffraction peaks observed in the range of 43.5° to 46° of the XRD pattern, the maximum intensity of the diffraction peak indicating the pseudo-spinel crystal structure is the largest. Lithium-ion rechargeable battery. XRD measurement conditions: A CR2032 type coin cell is fabricated using the above-mentioned positive electrode, lithium metal as the counter electrode, 1 mol/L lithium hexafluoride phosphate as the electrolyte of the electrolyte solution, a mixture of ethylene carbonate (EC) and diethyl carbonate (DEC) in a volume ratio of EC:DEC = 3:7 and vinylene carbonate (VC) at 2 wt%, polypropylene as the separator, and stainless steel for the positive and negative electrode cans. The fabricated coin cell is charged at a constant current of 0.5C (1C is the current value per positive electrode active material, which is 137 mA/g) to 4.6V in a 25°C environment, then charged at a constant voltage until the current value becomes 0.01C, the coin cell after constant voltage charging is disassembled in an argon atmosphere to remove the positive electrode, the positive electrode is washed with dimethyl carbonate, and then the positive electrode is measured by XRD.
  3. A lithium-ion secondary battery having a positive electrode and a negative electrode, The positive electrode has a positive electrode active material containing cobalt, oxygen, magnesium, fluorine, and titanium. The positive electrode active material contains lithium cobalt oxide, When the positive electrode was subjected to XRD measurement under the following XRD measurement conditions, the XRD pattern due to the CuKα1 line showed diffraction peaks indicating a pseudo-spinel type crystal structure at 2θ = 19.30 ± 0.20° and 2θ = 45.55 ± 0.10°. In the range of 43.5° to 46° of the XRD pattern, the maximum intensity of the diffraction peak indicating the pseudo-spinel crystal structure is greater than the maximum intensity of the diffraction peak indicating the H1-3 crystal structure. Lithium-ion rechargeable battery. XRD measurement conditions: A CR2032 type coin cell is fabricated using the above-mentioned positive electrode, lithium metal as the counter electrode, 1 mol/L lithium hexafluoride phosphate as the electrolyte of the electrolyte solution, a mixture of ethylene carbonate (EC) and diethyl carbonate (DEC) in a volume ratio of EC:DEC = 3:7 and vinylene carbonate (VC) at 2 wt%, polypropylene as the separator, and stainless steel for the positive and negative electrode cans. The fabricated coin cell is charged at a constant current of 0.5C (1C is the current value per positive electrode active material, which is 137 mA/g) to 4.6V in a 25°C environment, then charged at a constant voltage until the current value becomes 0.01C, the coin cell after constant voltage charging is disassembled in an argon atmosphere to remove the positive electrode, the positive electrode is washed with dimethyl carbonate, and then the positive electrode is measured by XRD.
  4. A lithium-ion secondary battery having a positive electrode and a negative electrode, The positive electrode has a positive electrode active material containing cobalt, oxygen, magnesium, fluorine, and titanium. The positive electrode active material contains lithium cobalt oxide, When the positive electrode was subjected to XRD measurement under the following XRD measurement conditions, the XRD pattern due to the CuKα1 line showed diffraction peaks indicating a pseudo-spinel type crystal structure at 2θ = 19.30 ± 0.20° and 2θ = 45.55 ± 0.10°. Among the diffraction peaks observed in the range of 43.5° to 46° of the aforementioned XRD pattern, the diffraction peak exhibiting the pseudo-spinel crystal structure has the largest maximum intensity. Lithium-ion rechargeable battery. XRD measurement conditions: A CR2032 type coin cell is fabricated using the above-mentioned positive electrode, lithium metal as the counter electrode, 1 mol/L lithium hexafluoride phosphate as the electrolyte of the electrolyte solution, a mixture of ethylene carbonate (EC) and diethyl carbonate (DEC) in a volume ratio of EC:DEC = 3:7 and vinylene carbonate (VC) at 2 wt%, polypropylene as the separator, and stainless steel for the positive and negative electrode cans. The fabricated coin cell is charged at a constant current of 0.5C (1C is the current value per positive electrode active material, which is 137 mA/g) to 4.6V in a 25°C environment, then charged at a constant voltage until the current value becomes 0.01C, the coin cell after constant voltage charging is disassembled in an argon atmosphere to remove the positive electrode, the positive electrode is washed with dimethyl carbonate, and then the positive electrode is measured by XRD.
  5. A lithium-ion secondary battery having a positive electrode and a negative electrode, The positive electrode has a positive electrode active material containing cobalt, oxygen, magnesium, fluorine, and titanium. The positive electrode active material contains lithium cobalt oxide, In the EDX radiation analysis of the positive electrode active material, the titanium concentration peak was located in a deeper region than the magnesium concentration peak. When the positive electrode was subjected to XRD measurement under the following XRD measurement conditions, the XRD pattern due to the CuKα1 line showed diffraction peaks indicating a pseudo-spinel type crystal structure at 2θ = 19.30 ± 0.20° and 2θ = 45.55 ± 0.10°. In the range of 19° to 20° of the XRD pattern, the maximum intensity of the diffraction peak indicating the pseudo-spinel crystal structure is greater than the maximum intensity of the diffraction peak indicating the H1-3 crystal structure, and in the range of 43.5° to 46° of the XRD pattern, the maximum intensity of the diffraction peak indicating the pseudo-spinel crystal structure is greater than the maximum intensity of the diffraction peak indicating the H1-3 crystal structure. Lithium-ion rechargeable battery. XRD measurement conditions: A CR2032 type coin cell is fabricated using the above-mentioned positive electrode, lithium metal as the counter electrode, 1 mol/L lithium hexafluoride phosphate as the electrolyte of the electrolyte solution, a mixture of ethylene carbonate (EC) and diethyl carbonate (DEC) in a volume ratio of EC:DEC = 3:7 and vinylene carbonate (VC) at 2 wt%, polypropylene as the separator, and stainless steel for the positive and negative electrode cans. The fabricated coin cell is charged at a constant current of 0.5C (1C is the current value per positive electrode active material, which is 137 mA/g) to 4.6V in a 25°C environment, then charged at a constant voltage until the current value becomes 0.01C, the coin cell after constant voltage charging is disassembled in an argon atmosphere to remove the positive electrode, the positive electrode is washed with dimethyl carbonate, and then the positive electrode is measured by XRD.
  6. A lithium-ion secondary battery having a positive electrode and a negative electrode, The positive electrode has a positive electrode active material containing cobalt, oxygen, magnesium, fluorine, and titanium. The positive electrode active material contains lithium cobalt oxide, In the EDX radiation analysis of the positive electrode active material, the titanium concentration peak was located in a deeper region than the magnesium concentration peak. When the positive electrode was subjected to XRD measurement under the following XRD measurement conditions, the XRD pattern due to the CuKα1 line showed diffraction peaks indicating a pseudo-spinel type crystal structure at 2θ = 19.30 ± 0.20° and 2θ = 45.55 ± 0.10°. Among the diffraction peaks observed in the range of 19° to 20° of the XRD pattern, the maximum intensity of the diffraction peak indicating the pseudo-spinel crystal structure is the largest, and among the diffraction peaks observed in the range of 43.5° to 46° of the XRD pattern, the maximum intensity of the diffraction peak indicating the pseudo-spinel crystal structure is the largest. Lithium-ion rechargeable battery. XRD measurement conditions: A CR2032 type coin cell is fabricated using the above-mentioned positive electrode, lithium metal as the counter electrode, 1 mol/L lithium hexafluoride phosphate as the electrolyte of the electrolyte solution, a mixture of ethylene carbonate (EC) and diethyl carbonate (DEC) in a volume ratio of EC:DEC = 3:7 and vinylene carbonate (VC) at 2 wt%, polypropylene as the separator, and stainless steel for the positive and negative electrode cans. The fabricated coin cell is charged at a constant current of 0.5C (1C is the current value per positive electrode active material, which is 137 mA/g) to 4.6V in a 25°C environment, then charged at a constant voltage until the current value becomes 0.01C, the coin cell after constant voltage charging is disassembled in an argon atmosphere to remove the positive electrode, the positive electrode is washed with dimethyl carbonate, and then the positive electrode is measured by XRD.
  7. A lithium-ion secondary battery having a positive electrode and a negative electrode, The positive electrode has a positive electrode active material containing cobalt, oxygen, magnesium, fluorine, and titanium. The positive electrode active material contains lithium cobalt oxide, In the EDX radiation analysis of the positive electrode active material, the titanium concentration peak was located in a deeper region than the magnesium concentration peak. When the positive electrode was subjected to XRD measurement under the following XRD measurement conditions, the XRD pattern due to the CuKα1 line showed diffraction peaks indicating a pseudo-spinel type crystal structure at 2θ = 19.30 ± 0.20° and 2θ = 45.55 ± 0.10°. In the range of 43.5° to 46° of the XRD pattern, the maximum intensity of the diffraction peak indicating the pseudo-spinel crystal structure is greater than the maximum intensity of the diffraction peak indicating the H1-3 crystal structure. Lithium-ion rechargeable battery. XRD measurement conditions: A CR2032 type coin cell is fabricated using the above-mentioned positive electrode, lithium metal as the counter electrode, 1 mol/L lithium hexafluoride phosphate as the electrolyte of the electrolyte solution, a mixture of ethylene carbonate (EC) and diethyl carbonate (DEC) in a volume ratio of EC:DEC = 3:7 and vinylene carbonate (VC) at 2 wt%, polypropylene as the separator, and stainless steel for the positive and negative electrode cans. The fabricated coin cell is charged at a constant current of 0.5C (1C is the current value per positive electrode active material, which is 137 mA/g) to 4.6V in a 25°C environment, then charged at a constant voltage until the current value becomes 0.01C, the coin cell after constant voltage charging is disassembled in an argon atmosphere to remove the positive electrode, the positive electrode is washed with dimethyl carbonate, and then the positive electrode is measured by XRD.
  8. A lithium-ion secondary battery having a positive electrode and a negative electrode, The positive electrode has a positive electrode active material containing cobalt, oxygen, magnesium, fluorine, and titanium. The positive electrode active material contains lithium cobalt oxide, In the EDX radiation analysis of the positive electrode active material, the titanium concentration peak was located in a deeper region than the magnesium concentration peak. When the positive electrode was subjected to XRD measurement under the following XRD measurement conditions, the XRD pattern due to the CuKα1 line showed diffraction peaks indicating a pseudo-spinel type crystal structure at 2θ = 19.30 ± 0.20° and 2θ = 45.55 ± 0.10°. Among the diffraction peaks observed in the range of 43.5° to 46° of the aforementioned XRD pattern, the diffraction peak exhibiting the pseudo-spinel crystal structure has the largest maximum intensity. Lithium-ion rechargeable battery. XRD measurement conditions: A CR2032 type coin cell is fabricated using the above-mentioned positive electrode, lithium metal as the counter electrode, 1 mol/L lithium hexafluoride phosphate as the electrolyte of the electrolyte solution, a mixture of ethylene carbonate (EC) and diethyl carbonate (DEC) in a volume ratio of EC:DEC = 3:7 and vinylene carbonate (VC) at 2 wt%, polypropylene as the separator, and stainless steel for the positive and negative electrode cans. The fabricated coin cell is charged at a constant current of 0.5C (1C is the current value per positive electrode active material, which is 137 mA/g) to 4.6V in a 25°C environment, then charged at a constant voltage until the current value becomes 0.01C, the coin cell after constant voltage charging is disassembled in an argon atmosphere to remove the positive electrode, the positive electrode is washed with dimethyl carbonate, and then the positive electrode is measured by XRD.

Description

One aspect of the present invention relates to a product, a method, or a method of manufacture. Alternatively, the present invention relates to a process. This relates to machines, manufacturers, or compositions of matter. One aspect of the present invention relates to semiconductor devices, display devices, light-emitting devices, energy storage devices, lighting devices, electronic devices, Or relating to methods for manufacturing them. In particular, relating to positive electrode active materials that can be used in secondary batteries, secondary batteries, and electronic devices having secondary batteries. In this specification, the term "energy storage device" refers to all elements and devices that have an energy storage function. For example, this includes rechargeable batteries (also called secondary batteries) such as lithium-ion secondary batteries, lithium-ion capacitors, and electric double-layer capacitors. Furthermore, in this specification, "electronic equipment" refers to all devices that have an energy storage device, and electro-optical devices with an energy storage device, information terminal devices with an energy storage device, etc., are all considered electronic equipment. In recent years, there has been a great deal of development on various energy storage devices, including lithium-ion secondary batteries, lithium-ion capacitors, and air batteries. In particular, lithium-ion secondary batteries, with their high output and high energy density, are being used in mobile information terminals such as mobile phones, smartphones, and notebook computers, portable music players, digital cameras, medical equipment, and next-generation clean energy vehicles (hybrid electric vehicles (HEVs), electric vehicles (EVs), and plug-in hybrid electric vehicles (PHEVs)). With the development of the semiconductor industry, demand for these technologies has expanded rapidly, and they have become indispensable to modern information society as a source of rechargeable energy. The characteristics required of lithium-ion secondary batteries include further increases in energy density, These improvements include enhanced cycle characteristics, safety in various operating environments, and improved long-term reliability. Therefore, improvements to the positive electrode active material are being considered to enhance the cycle characteristics and increase the capacity of lithium-ion secondary batteries (Patent Documents 1, 2, and 1). Research is also being conducted on the crystal structure of the positive electrode active material (Non-Patent Documents 2 to 4). Japanese Patent Publication No. 2006-164758Special Publication No. 2014-523840 Jae-Hyun Shim et al, “Characterization of Spinel LixCo2O4-Coated LiCoO2 Prepared with Post-Thermal Treatment as a Cathode Material for Lithium Ion Batteries”, CHEMISTRY OF MATERIALS, 2015, 27, pp. 3273-3279Toyoki Okumura et al, “Correlation of lithium ion distribution and X-ray absorption near-edge structure in O3-and “O2-lithium cobalt oxides from first-principle calculation”, Journal of Materials Chemistry, 2012, 22, pp. 17340-17348Motohashi, T. et al, “Electronic phase diagram of the layered cobalt oxide system LixCoO2 (0.0≦x≦1.0)”, Physical Review B, 80(16) ;165114Zhaohui Chen et al, “Staging Phase Transitions in LixCoO2”, Journal of The Electrochemical Society, 2002, 149(12) A1604-A1609 A diagram illustrating the charge depth and crystal structure of a positive electrode active material according to one embodiment of the present invention.A diagram illustrating the charging depth and crystal structure of a conventional positive electrode active material.XRD pattern calculated from crystal structure.A diagram illustrating the crystal structure and magnetism of a positive electrode active material according to one embodiment of the present invention.A diagram illustrating the crystal structure and magnetism of a conventional positive electrode active material.Cross-sectional view of the active material layer when a graphene compound is used as a conductive additive.A diagram illustrating how to charge a rechargeable battery.A diagram illustrating how to charge a rechargeable battery.A diagram illustrating the discharge method of a secondary battery.A diagram illustrating a coin-type rechargeable battery.A diagram illustrating a cylindrical rechargeable battery.A diagram illustrating an example of a secondary battery.A diagram illustrating an example of a secondary battery.A diagram illustrating an example of a secondary battery.A diagram illustrating an example of a secondary battery.A diagram illustrating a laminated rechargeable battery.A diagram illustrating a laminated rechargeable battery.A diagram showing the external appearance of a secondary battery.A diagram showing the external appearance of a secondary battery.A diagram illustrating the method for manufacturing a secondary battery.A diagram illustrating a rechargeable battery that can be bent.A diagram illu