US2023299274A1PendingUtilityA1

Positive electrode active material particle and manufacturing method of positive electrode active material particle

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Assignee: SEMICONDUCTOR ENERGY LABPriority: Oct 12, 2016Filed: May 25, 2023Published: Sep 21, 2023
Est. expiryOct 12, 2036(~10.2 yrs left)· nominal 20-yr term from priority
Inventors:Takahiro KawakamiTeruaki OchiaiYohei MommaAyae TsurutaMasahiro TakahashiMayumi Mikami
H01M 10/0525H01M 4/366H01M 4/525H01M 2004/028H01M 4/0471H01M 4/62H01G 11/24H01G 11/86H01G 11/50H01M 4/628Y02T10/70Y02E60/10Y02P70/50C01P 2004/80C01G 51/42H01G 11/60H01M 4/505H01M 4/485H01M 4/131
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Claims

Abstract

Provided is a positive electrode active material which suppresses a reduction in capacity due to charge and discharge cycles when used in a lithium ion secondary battery. A covering layer is formed by segregation on a superficial portion of the positive electrode active material. The positive electrode active material includes a first region and a second region. The first region exists in an inner portion of the positive electrode active material. The second region exists in a superficial portion of the positive electrode active material and part of the inner portion thereof. The first region includes lithium, a transition metal, and oxygen. The second region includes magnesium, fluorine, and oxygen.

Claims

exact text as granted — not AI-modified
1 . A lithium-ion secondary battery comprising a positive electrode,
 a negative electrode, and an electrolyte solution,   wherein the positive electrode comprises a positive electrode active material comprising lithium cobalt oxide,   wherein the positive electrode active material comprises a first region, a second region, and a third region,   wherein the second region and the third region are provided outside the first region,   wherein the first region comprises a layered rock-salt crystal structure,   wherein the second region comprises fluorine, COO(II), and magnesium oxide having a rock-salt crystal structure,   wherein part of magnesium of the magnesium oxide is bonded to fluorine,   wherein the first region comprises a first analysis point and the second region comprises a second analysis point,   wherein a proportion of divalent cobalt in the second analysis point is larger than a proportion of divalent cobalt in the first analysis point,   wherein the proportion of divalent cobalt is measured by EELS,   wherein the third region comprises an electrolyte decomposition product, and   wherein the negative electrode comprises a negative electrode active material comprising carbon.   
     
     
         2 . A lithium-ion secondary battery comprising a positive electrode,
 a negative electrode, and an electrolyte solution,   wherein the positive electrode comprises a positive electrode active material comprising lithium cobalt oxide,   wherein the positive electrode active material comprises a first region, a second region, and a third region,   wherein the second region and the third region are provided outside the first region,   wherein the first region comprises a layered rock-salt crystal structure,   wherein the second region comprises fluorine, CoO(II), and magnesium oxide having a rock-salt crystal structure,   wherein part of oxygen of the magnesium oxide is substituted with fluorine,   wherein the first region comprises a first analysis point and the second region comprises a second analysis point,   wherein a proportion of divalent cobalt in the second analysis point is larger than a proportion of divalent cobalt in the first analysis point,   wherein the proportion of divalent cobalt is measured by EELS,   wherein the third region comprises an electrolyte decomposition product, and   wherein the negative electrode comprises a negative electrode active material comprising carbon.   
     
     
         3 . A lithium-ion secondary battery comprising a positive electrode, a negative electrode, and an electrolyte solution,
 wherein the positive electrode comprises a positive electrode active material comprising lithium cobalt oxide,   wherein the positive electrode active material comprises a first region, a second region, and a third region,   wherein the second region and the third region are provided outside the first region,   wherein the first region comprises a layered rock-salt crystal structure,   wherein the second region comprises fluorine, COO(II), and magnesium oxide having a rock-salt crystal structure,   wherein a distribution of fluorine overlaps with a distribution of magnesium in the second region,   wherein the first region comprises a first analysis point and the second region comprises a second analysis point,   wherein a proportion of divalent cobalt in the second analysis point is larger than a proportion of divalent cobalt in the first analysis point,   wherein the proportion of divalent cobalt is measured by EELS,   wherein the third region comprises an electrolyte decomposition product, and   wherein the negative electrode comprises a negative electrode active material comprising carbon.   
     
     
         4 . The lithium-ion secondary battery according to  claim 1 ,
 wherein a ratio of a concentration of magnesium to a concentration of fluorine is Mg:F=y:1 (3≤y≤5) (atomic ratio) when an XPS analysis is performed on a surface of the positive electrode active material.   
     
     
         5 . The lithium-ion secondary battery according to  claim 1 ,
 wherein the electrolyte solution comprises an electrolyte comprising lithium hexafluorophosphate, and   wherein the electrolyte solution comprises ethylene carbonate, diethyl carbonate, and vinylene carbonate.   
     
     
         6 . The lithium-ion secondary battery according to  claim 1 ,
 wherein the electrolyte solution comprises vinylene carbonate.   
     
     
         7 . The lithium-ion secondary battery according to  claim 1 ,
 wherein the electrolyte solution comprises ethylene carbonate and diethyl carbonate at a volume ratio of 3:7 and vinylene carbonate at a 2 weight %.   
     
     
         8 . The lithium-ion secondary battery according to  claim 1 ,
 wherein a peak position of a bonding energy of fluorine of the positive electrode active material that is measured by X-ray photoelectron spectroscopy is 682 eV or more and less than 685 eV.   
     
     
         9 . The lithium-ion secondary battery according to  claim 1 ,
 wherein the second region is a region from a surface of the positive electrode active material to a depth where a concentration of magnesium in a depth direction is ⅕ of a maximum peak of the concentration of magnesium in EDX analysis of the positive electrode active material.   
     
     
         10 . The lithium-ion secondary battery according to  claim 1 ,
 wherein a peak of a concentration of fluorine exists in a region from a surface of the positive electrode active material to a depth of 1 nm in EDX analysis of the positive electrode active material.   
     
     
         11 . The lithium-ion secondary battery according to  claim 1 ,
 wherein L 3 /L 2  of the second analysis point is 3.8 or more and,   wherein the L 3 /L 2  is an EELS spectral intensity ratios of an L 2  level of cobalt and an L 3  level of cobalt.   
     
     
         12 . The lithium-ion secondary battery according to  claim 1 ,
 wherein L 3 /L 2  of the first analysis point is less than 3.8, and   wherein the L 3 /L 2  is an EELS spectral intensity ratios of an L 2  level of cobalt and an L 3  level of cobalt.   
     
     
         13 . The lithium-ion secondary battery according to  claim 2 ,
 wherein a ratio of a concentration of magnesium to a concentration of fluorine is Mg:F=y:1 (35≤y≤5) (atomic ratio) when an XPS analysis is performed on a surface of the positive electrode active material.   
     
     
         14 . The lithium-ion secondary battery according to  claim 2 ,
 wherein the electrolyte solution comprises an electrolyte comprising lithium hexafluorophosphate, and   wherein the electrolyte solution comprises ethylene carbonate, diethyl carbonate, and vinylene carbonate.   
     
     
         15 . The lithium-ion secondary battery according to  claim 2 ,
 wherein the electrolyte solution comprises vinylene carbonate.   
     
     
         16 . The lithium-ion secondary battery according to  claim 2 ,
 wherein the electrolyte solution comprises ethylene carbonate and diethyl carbonate at a volume ratio of 3:7 and vinylene carbonate at a 2 weight %.   
     
     
         17 . The lithium-ion secondary battery according to  claim 2 ,
 wherein a peak position of a bonding energy of fluorine of the positive electrode active material that is measured by X-ray photoelectron spectroscopy is 682 eV or more and less than 685 eV.   
     
     
         18 . The lithium-ion secondary battery according to  claim 2 ,
 wherein the second region is a region from a surface of the positive electrode active material to a depth where a concentration of magnesium in a depth direction is ⅕ of a maximum peak of the concentration of magnesium in EDX analysis of the positive electrode active material.   
     
     
         19 . The lithium-ion secondary battery according to  claim 2 ,
 wherein a peak of a concentration of fluorine exists in a region from a surface of the positive electrode active material to a depth of 1 nm in EDX analysis of the positive electrode active material.   
     
     
         20 . The lithium-ion secondary battery according to  claim 2 ,
 wherein L 3 /L 2  of the second analysis point is 3.8 or more and,   wherein the L 3 /L 2  is an EELS spectral intensity ratios of an L 2  level of cobalt and an L 3  level of cobalt.   
     
     
         21 . The lithium-ion secondary battery according to  claim 2 ,
 wherein L 3 /L 2  of the first analysis point is less than 3.8, and   wherein the L 3 /L 2  is an EELS spectral intensity ratios of an L 2  level of cobalt and an L 3  level of cobalt.   
     
     
         22 . The lithium-ion secondary battery according to  claim 3 ,
 wherein a ratio of a concentration of magnesium to a concentration of fluorine is Mg:F=y:1 (3≤y≤5) (atomic ratio) when an XPS analysis is performed on a surface of the positive electrode active material.   
     
     
         23 . The lithium-ion secondary battery according to  claim 3 ,
 wherein the electrolyte solution comprises an electrolyte comprising lithium hexafluorophosphate, and   wherein the electrolyte solution comprises ethylene carbonate, diethyl carbonate, and vinylene carbonate.   
     
     
         24 . The lithium-ion secondary battery according to  claim 3 ,
 wherein the electrolyte solution comprises vinylene carbonate.   
     
     
         25 . The lithium-ion secondary battery according to  claim 3 ,
 wherein the electrolyte solution comprises ethylene carbonate and diethyl carbonate at a volume ratio of 3:7 and vinylene carbonate at a 2 weight %.   
     
     
         26 . The lithium-ion secondary battery according to  claim 3 ,
 wherein a peak position of a bonding energy of fluorine of the positive electrode active material that is measured by X-ray photoelectron spectroscopy is 682 eV or more and less than 685 eV.   
     
     
         27 . The lithium-ion secondary battery according to  claim 3 ,
 wherein the second region is a region from a surface of the positive electrode active material to a depth where a concentration of magnesium in a depth direction is ⅕ of a maximum peak of the concentration of magnesium in EDX analysis of the positive electrode active material.   
     
     
         28 . The lithium-ion secondary battery according to  claim 3 ,
 wherein a peak of a concentration of fluorine exists in a region from a surface of the positive electrode active material to a depth of 1 nm in EDX analysis of the positive electrode active material.   
     
     
         29 . The lithium-ion secondary battery according to  claim 3 ,
 wherein L 3 /L 2  of the second analysis point is 3.8 or more and,   wherein the L 3 /L 2  is an EELS spectral intensity ratios of an L 2  level of cobalt and an L 3  level of cobalt.   
     
     
         30 . The lithium-ion secondary battery according to  claim 3 ,
 wherein L 3 /L 2  of the first analysis point is less than 3.8, and   wherein the L 3 /L 2  is an EELS spectral intensity ratios of an L 2  level of cobalt and an L 3  level of cobalt.

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