Method for making LiFePO4 by hydrothermal method

Patent metadata

Field	Value
Publication number	US-11799084-B2
Application number	US-202217692502-A
Country	US
Kind code	B2
Filing date	Mar 11, 2022
Priority date	Aug 31, 2011
Publication date	Oct 24, 2023
Grant date	Oct 24, 2023

Abstract

A hydrothermal synthesis for LiFePO4 is provided. First, each raw material solution is prepared using a degassed water in advance, second, those solution are mixed by dripping in a fixed order, and then those materials are reacted in a hydrothermal synthesis, so that LiFePO4 is obtained in a predesigned form.

First claim

What is claimed is:

1. A method for manufacturing a complex oxide comprising the steps of:
preparing a solution comprising lithium by dissolving a compound comprising lithium in water with an oxygen concentration lower than or equal to 4.5 ppm under an atmosphere with an oxygen concentration lower than air;
preparing a solution comprising phosphorous by dissolving a compound comprising phosphorous in water with an oxygen concentration lower than or equal to 4.5 ppm under an atmosphere with an oxygen concentration lower than air;
preparing a solution comprising lithium and phosphorous by mixing the solution comprising lithium and the solution comprising phosphorous under an atmosphere with an oxygen concentration lower than air;
preparing a solution comprising iron by dissolving a compound comprising iron in water with an oxygen concentration lower than or equal to 4.5 ppm under an atmosphere with an oxygen concentration lower than air;
preparing a mixed solution by mixing the solution comprising lithium and phosphorous and the solution comprising iron under an atmosphere with an oxygen concentration lower than air; and
obtaining a complex oxide represented by Formula LiFePO 4 , by performing a hydrothermal method on the mixed solution,
wherein the mixed solution is prepared by dripping the solution comprising lithium and phosphorous into the solution comprising iron while mixing the solution comprising iron.

2. A method for manufacturing a complex oxide comprising the steps of:
preparing a solution comprising lithium by dissolving a compound comprising lithium in water degassed by bubbling nitrogen under an atmosphere with an oxygen concentration lower than air;
preparing a solution comprising phosphorous by dissolving a compound comprising phosphorous in water degassed by bubbling nitrogen under an atmosphere with an oxygen concentration lower than air;
preparing a solution comprising lithium and phosphorous by mixing the solution comprising lithium and the solution comprising phosphorous under an atmosphere with an oxygen concentration lower than air;
preparing a solution comprising iron by dissolving a compound comprising iron in water degassed by bubbling nitrogen under an atmosphere with an oxygen concentration lower than air;
preparing a mixed solution by mixing the solution comprising lithium and phosphorous and the solution comprising iron under an atmosphere with an oxygen concentration lower than air; and
obtaining a complex oxide represented by Formula LiFePO 4 , by performing a hydrothermal method on the mixed solution,
wherein the mixed solution is prepared by dripping the solution comprising lithium and phosphorous into the solution comprising iron while mixing the solution comprising iron.

Assignees

• Semiconductor Energy Lab

Inventors

• Miwa Takuya
• Nomoto Kuniharu
• Momo Junpei

Classifications

• C01G53/82

  Compounds containing nickel, with or without oxygen or hydrogen, and containing two or more other elements · CPC title

• C01G51/82

  Compounds containing cobalt, with or without oxygen or hydrogen, and containing two or more other elements · CPC title

• C01G45/22

  Compounds containing manganese, with or without oxygen or hydrogen, and containing two or more other elements · CPC title

• H01M4/5825 Primary

  Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines · CPC title

• C01D15/02

  Oxides; Hydroxides · CPC title