Production method for positive electrode active material
View Patent ↗A method for producing a positive electrode active material, includes the steps of (1) bringing an electrode mixture containing a positive electrode active material, a binder, and an electrolyte into contact with an electrolyte cleaning solvent to obtain a slurry containing a solid component and a liquid component, and then separating the slurry into the solid component and the liquid component, wherein an amount of P in the liquid component after separation is 0.0020 to 2.0 mass %, an amount of F in the liquid component after separation is 0.01 to 7.0 mass %, and an amount of P remaining in the solid component after separation is 0.7 mass % or less; (2) mixing an activation treatment agent with the separated solid component; and (3) heating a mixture obtained to activate the positive electrode active material contained in the mixture.
1 . A method for producing a positive electrode active material, comprising the steps of:
(1) bringing an electrode mixture containing a positive electrode active material, a binder, and an electrolyte into contact with an electrolyte cleaning solvent to obtain a slurry containing a solid component and a liquid component, and then separating the slurry into the solid component and the liquid component, wherein an amount of P in the liquid component after separation is 0.0020 to 2.0 mass %, an amount of F in the liquid component after separation is 0.01 to 7.0 mass %, and an amount of P remaining in the solid component after separation is 0.7 mass % or less;
(2) mixing an activation treatment agent containing one type or two or more types of alkali metal compounds with the separated solid component; and
(3) heating a mixture obtained to a holding temperature equal to or higher than a melting start temperature of the activation treatment agent to activate the positive electrode active material contained in the mixture.
2 . The method according to claim 1 , wherein the positive electrode active material is a composite oxide containing one or more types of elements selected from the following element group 1 and one or more types of elements selected from the following element group 2:
element group 1: Ni, Co, Mn, Fe, Al, and P;
element group 2: Li, Na, K, Ca, Sr, Ba, and Mg.
3 . The method according to claim 1 , wherein the positive electrode active material is represented by the following formula:
wherein M 2 represents at least one type of element selected from the group consisting of Na, K, Ca, Sr, Ba, and Mg,
M 1 represents at least one type of element selected from the group consisting of Ni, Co, Mn, Fe, Al, and P,
M T represents at least one type of element selected from the group consisting of transition metal elements other than Ni, Co, Mn and Fe,
X represents at least one type of element selected from the group consisting of nonmetallic elements except O and P, and
−0.4<a<1.5, 0≤b<0.5, 0≤c<0.5, −0.5<d<1.5, and 0≤e<0.5 are satisfied.
4 . The method according to claim 1 , wherein in the step (1), a concentration of the solid component with respective to a volume of the slurry is 3 to 2,000 g/L.
5 . The method according to claim 1 , wherein in the step (1), a contact time between the solid component and the liquid component is 1 minute or more and less than 25 hours.
6 . The method according to claim 1 , wherein in the step (1), the electrode mixture and the electrolyte cleaning solvent are stirred to obtain the slurry.