Patent ID: 11936043
Assignee: SEMICONDUCTOR ENERGY LABORATORY CO., LTD.
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H  C  Y | IPC C  H

Claim 0:
1. A method for manufacturing a positive electrode active material comprising lithium, phosphorus, iron, and oxygen, comprising steps of:
forming a first mixed solution by mixing a lithium compound, a phosphorus compound, and a first solvent;
forming a second mixed solution by adjusting pH by adding a first aqueous solution to the first mixed solution;
forming a third mixed solution by mixing an iron compound with the second mixed solution after the step of forming the second mixed solution;
forming a fourth mixed solution by mixing the third mixed solution and a second solvent after the step of forming the third mixed solution; and
performing heat treatment on the fourth mixed solution at a temperature higher than or equal to 100° C. and lower than or equal to 350° C.,
wherein a pH of the fourth mixed solution is more than or equal to 3.0 and less than or equal to 6.0, and
wherein the positive electrode active material comprises a crystal structure belonging to a space group Pnma.