Preparation method for positive electrode material for secondary battery

Patent metadata

Field	Value
Publication number	US-2018198119-A1
Application number	US-201515506443-A
Country	US
Kind code	A1
Filing date	Jun 18, 2015
Priority date	Sep 1, 2014
Publication date	Jul 12, 2018
Grant date	—

Abstract

Disclosed is a method of preparing a cathode electrode material for a secondary battery, including a hydrate precursor preparation step of preparing a manganese phosphate hydrate precursor using a coprecipitation process, a synthetic powder preparation step of preparing a synthetic powder by mixing the manganese phosphate hydrate precursor in a powder form with lithium phosphate and carbon, an oxide material powder preparation step of preparing a lithium manganese phosphate oxide material powder by milling and annealing the synthetic powder, a composite powder preparation step of preparing a composite powder by mixing the lithium manganese phosphate oxide material powder with a Li 2 MnO 3 -based cathode material, and a slurry preparation step of preparing a slurry by mixing the composite powder with a conductor and a binder.

First claim

1 . A method of preparing a cathode material for a secondary battery, comprising:
a hydrate precursor preparation step of preparing a manganese phosphate hydrate precursor using a coprecipitation process; a synthetic powder preparation step of preparing a synthetic powder by mixing the manganese phosphate hydrate precursor in a powder form with lithium phosphate and carbon; an oxide material powder preparation step of preparing a lithium manganese phosphate oxide material powder by milling and annealing the synthetic powder; a composite powder preparation step of preparing a composite powder by mixing the lithium manganese phosphate oxide material powder with a Li 2 MnO 3 -based cathode material; and a slurry preparation step of preparing a slurry by mixing the composite powder with a conductor and a binder.

2 . The method of claim 1 , wherein the hydrate precursor preparation step comprises:
forming a 1 M metal solution by dissolving 1 mol of a manganese sulfate hydrate and 0.33 to 1 mol of phosphoric acid in distilled water; forming a 1 M aqueous solution by mixing ammonia water and distilled water to control a pH in a reactor; performing a coprecipitation reaction by stirring the metal solution and the aqueous solution under a condition that the pH is adjusted to 5 to 11 and a stirring rate and a temperature of the reactor are maintained constant; removing impurities by repeating water washing and filtration of a precipitate obtained through aging for 10 to 60 hr after completion of the coprecipitation reaction; and obtaining a manganese phosphate hydrate precursor by filtering and then drying the precipitate after completion of the water washing for removing the impurities.

3 . The method of claim 1 , wherein the synthetic powder preparation step comprises:
primarily heat-treating the manganese phosphate hydrate precursor at 300° C. to 700° C. for 1 to 24 hr; mixing 1 mol of the primarily heat-treated precursor with 0.9 to 1.3 mol of lithium phosphate to give a precursor mixture, mixing 100 parts by weight of the precursor mixture containing the lithium phosphate with 18 to 33 parts by weight of carbon, and performing stirring at a predetermined stirring rate for 30 min to 6 hr; making a pellet by press-molding the stirred precursor; and secondarily heat-treating the pellet at 500° C. to 700° C. for 1 to 24 hr.

4 . The method of claim 3 , wherein the oxide material powder preparation step comprises:
milling the synthetic powder, obtained through the secondarily heat-treating, at a predetermined stirring rate using a planetary ball mill; and annealing the milled synthetic powder at 600° C. to 700° C. for 30 min to 2 hr in order to increase a crystallinity thereof.

5 . The method of claim 1 , wherein the composite powder preparation step comprises mixing 100 parts by weight of the lithium manganese phosphate oxide material powder with 82 to 122 parts by weight of the Li 2 MnO 3 -based cathode material.

6 . The method of claim 1 , wherein the slurry preparation step comprises mixing 100 parts by weight of the composite powder, 5 to 22 parts by weight of the conductor, and 5 to 22 parts by weight of the binder.

Assignees

• Korea Inst Ind Tech

Inventors

• Kim Ho Sung
• Kang Byeong Su
• Yang Sun Woo
• Kim Min Young
• Jeong Chae Hwan

Classifications

• C01B25/451

  containing metal and ammonium · CPC title

• B01J2/22

  by pressing in moulds or between rollers · CPC title

• H01M4/5825

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

• C01B25/45 Primary

  containing plural metal, or metal and ammonium · CPC title

• H01M2004/028

  Positive electrodes · CPC title