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

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.

1 . A method for manufacturing a lithium-ion secondary battery, the lithium-ion secondary battery comprising a positive electrode comprising a positive electrode active material particle, a negative electrode, and an electrolyte solution, the method comprising the step of:
 heating a material comprising lithium, nickel, cobalt, manganese, magnesium, oxygen, and fluorine,   wherein magnesium is segregated in a superficial portion of the positive electrode active material particle and in a portion including a crystal defect of the positive electrode active material particle by the heating of the material.   
     
     
         2 . A method for manufacturing a lithium-ion secondary battery, the lithium-ion secondary battery comprising a positive electrode comprising a positive electrode active material particle, a negative electrode, and an electrolyte solution, the method comprising the step of:
 heating a material comprising lithium, nickel, cobalt, manganese, magnesium, oxygen, and fluorine,   wherein magnesium is segregated in a superficial portion of the positive electrode active material particle and in a portion including a crystal defect of the positive electrode active material particle by the heating of the material,   wherein a concentration ratio between magnesium and fluorine of a surface of the positive electrode active material particle after segregation is represented by Mg:F=y:1, and   wherein the y is greater than or equal to 3 and less than or equal to 5.   
     
     
         3 . A method for manufacturing a lithium-ion secondary battery, the lithium-ion secondary battery comprising a positive electrode comprising a positive electrode active material particle, a negative electrode, and an electrolyte solution, the method comprising the step of:
 heating a material comprising lithium, nickel, cobalt, manganese, magnesium, oxygen, and fluorine,   wherein the heating of the material is performed at a temperature higher than or equal to 500° C. and lower than or equal to 1200° C. for 50 hours or shorter,   wherein the heating of the material is performed in an oxygen-containing atmosphere, and   wherein magnesium is segregated in a superficial portion of the positive electrode active material particle by the heating of the material.   
     
     
         4 . A method for manufacturing a lithium-ion secondary battery, the lithium-ion secondary battery comprising a positive electrode comprising a positive electrode active material particle, a negative electrode, and an electrolyte solution, the method comprising the step of:
 heating a material comprising lithium, nickel, cobalt, manganese, magnesium, oxygen, and fluorine,   wherein the heating of the material is performed at a temperature higher than or equal to 500° C. and lower than or equal to 1200° C. for 50 hours or shorter,   wherein the heating of the material is performed in an oxygen-containing atmosphere,   wherein magnesium is segregated in a superficial portion of the positive electrode active material particle by the heating of the material,   wherein a concentration ratio between magnesium and fluorine of a surface of the positive electrode active material particle after segregation is represented by Mg:F=y:1, and   wherein the y is greater than or equal to 3 and less than or equal to 5.   
     
     
         5 . The method for manufacturing a lithium-ion secondary battery according to  claim 1 ,
 wherein the heating of the material is performed at a temperature higher than or equal to 700° C. and lower than or equal to 1000° C.   
     
     
         6 . The method for manufacturing a lithium-ion secondary battery according to  claim 2 ,
 wherein the heating of the material is performed at a temperature higher than or equal to 700° C. and lower than or equal to 1000° C.   
     
     
         7 . The method for manufacturing a lithium-ion secondary battery according to  claim 3 ,
 wherein the heating of the material is performed at a temperature higher than or equal to 700° C. and lower than or equal to 1000° C.   
     
     
         8 . The method for manufacturing a lithium-ion secondary battery according to  claim 4 ,
 wherein the heating of the material is performed at a temperature higher than or equal to 700° C. and lower than or equal to 1000° C.   
     
     
         9 . The method for manufacturing a lithium-ion secondary battery according to  claim 5 ,
 wherein the heating of the material is performed at about 800° C.   
     
     
         10 . The method for manufacturing a lithium-ion secondary battery according to  claim 6 ,
 wherein the heating of the material is performed at about 800° C.   
     
     
         11 . The method for manufacturing a lithium-ion secondary battery according to  claim 7 ,
 wherein the heating of the material is performed at about 800° C.   
     
     
         12 . The method for manufacturing a lithium-ion secondary battery according to  claim 8 ,
 wherein the heating of the material is performed at about 800° C.   
     
     
         13 . The method for manufacturing a lithium-ion secondary battery according to  claim 5 , further comprising the step of:
 cooling the heated material to room temperature after the heating of the material,   wherein cooling time is equal to or longer than the temperature rising time of the heating of the material.   
     
     
         14 . The method for manufacturing a lithium-ion secondary battery according to  claim 6 , further comprising the step of:
 cooling the heated material to room temperature after the heating of the material,   wherein cooling time is equal to or longer than the temperature rising time of the heating of the material.   
     
     
         15 . The method for manufacturing a lithium-ion secondary battery according to  claim 7 , further comprising the step of:
 cooling the heated material to room temperature after the heating of the material,   wherein cooling time is equal to or longer than the temperature rising time of the heating of the material.   
     
     
         16 . The method for manufacturing a lithium-ion secondary battery according to  claim 8 , further comprising the step of:
 cooling the heated material to room temperature after the heating of the material,   wherein cooling time is equal to or longer than the temperature rising time of the heating of the material.   
     
     
         17 . The method for manufacturing a lithium-ion secondary battery according to  claim 1 , further comprising steps of:
 mixing a lithium source, a cobalt source, a magnesium source, and a fluorine source; and   heating the mixture,   wherein the heating of the mixture is performed at a temperature higher than or equal to 800° C. and lower than or equal to 1050° C., and wherein the heating of the mixture is performed for greater than or equal to 2 hours and less than or equal to 20 hours.   
     
     
         18 . The method for manufacturing a lithium-ion secondary battery according to  claim 2 , further comprising steps of:
 mixing a lithium source, a cobalt source, a magnesium source, and a fluorine source; and   heating the mixture,   wherein the heating of the mixture is performed at a temperature higher than or equal to 800° C. and lower than or equal to 1050° C., and   wherein the heating of the mixture is performed for greater than or equal to 2 hours and less than or equal to 20 hours.   
     
     
         19 . The method for manufacturing a lithium-ion secondary battery according to  claim 3 , further comprising steps of:
 mixing a lithium source, a cobalt source, a magnesium source, and a fluorine source; and   heating the mixture,   wherein the heating of the mixture is performed at a temperature higher than or equal to 800° C. and lower than or equal to 1050° C., and   wherein the heating of the mixture is performed for greater than or equal to 2 hours and less than or equal to 20 hours.   
     
     
         20 . The method for manufacturing a lithium-ion secondary battery according to  claim 4 , further comprising steps of:
 mixing a lithium source, a cobalt source, a magnesium source, and a fluorine source; and   heating the mixture,   wherein the heating of the mixture is performed at a temperature higher than or equal to 800° C. and lower than or equal to 1050° C., and   wherein the heating of the mixture is performed for greater than or equal to 2 hours and less than or equal to 20 hours.   
     
     
         21 . The method for manufacturing a lithium-ion secondary battery according to  claim 17 ,
 wherein the heating of the mixture is performed at a temperature higher than or equal to 900° C. and lower than or equal to 1000° C.   
     
     
         22 . The method for manufacturing a lithium-ion secondary battery according to  claim 18 ,
 wherein the heating of the mixture is performed at a temperature higher than or equal to 900° C. and lower than or equal to 1000° C.   
     
     
         23 . The method for manufacturing a lithium-ion secondary battery according to  claim 19 ,
 wherein the heating of the mixture is performed at a temperature higher than or equal to 900° C. and lower than or equal to 1000° C.   
     
     
         24 . The method for manufacturing a lithium-ion secondary battery according to  claim 20 ,
 wherein the heating of the mixture is performed at a temperature higher than or equal to 900° C. and lower than or equal to 1000° C.   
     
     
         25 . The method for manufacturing a lithium-ion secondary battery according to  claim 17 , further comprising the step of:
 cooling the heated mixture to room temperature after the heating of the mixture,   wherein cooling time is equal to or longer than the temperature rising time of the heating of the mixture.   
     
     
         26 . The method for manufacturing a lithium-ion secondary battery according to  claim 18 , further comprising the step of:
 cooling the heated mixture to room temperature after the heating of the mixture,   wherein cooling time is equal to or longer than the temperature rising time of the heating of the mixture.   
     
     
         27 . The method for manufacturing a lithium-ion secondary battery according to  claim 19 , further comprising the step of:
 cooling the heated mixture to room temperature after the heating of the mixture,   wherein cooling time is equal to or longer than the temperature rising time of the heating of the mixture.   
     
     
         28 . The method for manufacturing a lithium-ion secondary battery according to  claim 20 , further comprising the step of:
 cooling the heated mixture to room temperature after the heating of the mixture,   wherein cooling time is equal to or longer than the temperature rising time of the heating of the mixture.   
     
     
         29 . The method for manufacturing a lithium-ion secondary battery according to  claim 17 ,
 wherein an atomic ratio of magnesium included in the magnesium source and fluorine included in the fluorine source is represented by Mg:F=1:x,   wherein the x is greater than or equal to 1.5 and lower than or equal to 4.   
     
     
         30 . The method for manufacturing a lithium-ion secondary battery according to  claim 18 ,
 wherein an atomic ratio of magnesium included in the magnesium source and fluorine included in the fluorine source is represented by Mg:F=1:x,   wherein the x is greater than or equal to 1.5 and lower than or equal to 4.   
     
     
         31 . The method for manufacturing a lithium-ion secondary battery according to  claim 19 ,
 wherein an atomic ratio of magnesium included in the magnesium source and fluorine included in the fluorine source is represented by Mg:F=1:x,   wherein the x is greater than or equal to 1.5 and lower than or equal to 4.   
     
     
         32 . The method for manufacturing a lithium-ion secondary battery according to  claim 20 ,
 wherein an atomic ratio of magnesium included in the magnesium source and fluorine included in the fluorine source is represented by Mg:F=1:x,   wherein the x is greater than or equal to 1.5 and lower than or equal to 4.   
     
     
         33 . The method for manufacturing a lithium-ion secondary battery according to  claim 17 ,
 wherein the heating of the mixture is performed in a dried atmosphere, and   wherein dew point in the dried atmosphere is preferably lower than or equal to −50° C.   
     
     
         34 . The method for manufacturing a lithium-ion secondary battery according to  claim 18 ,
 wherein the heating of the mixture is performed in a dried atmosphere, and   wherein dew point in the dried atmosphere is preferably lower than or equal to −50° C.   
     
     
         35 . The method for manufacturing a lithium-ion secondary battery according to  claim 19 ,
 wherein the heating of the mixture is performed in a dried atmosphere, and   wherein dew point in the dried atmosphere is preferably lower than or equal to −50° C.   
     
     
         36 . The method for manufacturing a lithium-ion secondary battery according to  claim 20 ,
 wherein the heating of the mixture is performed in a dried atmosphere, and   wherein dew point in the dried atmosphere is preferably lower than or equal to −50° C.