Preparation method of lithium iron phosphate monocrystalline nanorods

Abstract

The invention relates to a preparation method of lithium iron phosphate monocrystalline nanorods. The method is characterized in that: mixed solvent required by solvothermal reaction is constituted by ethylene glycol and water at volume ratio of 3:1-1:3; and polyethylene glycol is introduced to influence crystal nucleus formation and crystal growth, and realize solvothermal synthesis of lithium iron phosphate monocrystalline nanorods. The preparation method includes dissolving antioxidant ascorbic acid in the mixed solvent of ethylene glycol and water; sequentially dissolving phosphoric acid and ferrous sulfate hexahydrate in the mixed solvent; dropwise adding lithium hydroxide dissolved in ethylene glycol and water into the above solution containing phosphoric acid, ferrous sulfate and ascorbic acid; mixing with appropriate amount of polyethylene glycol; sealing in a reaction kettle system; and performing solvothermal reaction under high temperature 160-240 DEG C and high pressure, to obtain lithium iron phosphate monocrystalline nanorods. The product has stable quality, high purity and good particle dispersivity, which facilitates lithium ion diffusion and improves electrochemical performance of lithium ion battery. The preparation method has the advantages of simple preparation process, easy control, no pollution, low cost, and easy mass production.

Description

technical field

[0001] The invention relates to a preparation method of lithium iron phosphate single crystal nanorods, belonging to the fields of inorganic non-metallic materials and energy storage battery materials. Background technique

[0002] Lithium-ion battery, as a high-performance rechargeable green power source, has been widely used in various portable electronic products and communication tools in recent years, and has been gradually developed as a power source for electric vehicles, thereby promoting its development towards safety, environmental protection, Development in the direction of low cost and high specific energy. Among them, the development of new electrode materials, especially positive electrode materials, is extremely critical. At present, the widely studied cathode materials for lithium-ion batteries focus on transition metal oxides of lithium such as LiMO with a layered structure. 2 (M=Co, Ni, Mn) and LiMn with spinel structure 2 o 4 . However...

Examples

example 1

[0021] The preparation method comprises the following steps:

[0022] 1) Measure 20ml of ethylene glycol and 20ml of deionized water, and mix them to prepare a mixed solvent of ethylene glycol and water.

[0023] 2) Measure and weigh 0.1 g of ascorbic acid and dissolve it in the mixed solvent of ethylene glycol and water prepared in step 1), and stir for 30 minutes to fully dissolve it.

[0024] 3) According to the mol ratio of P and Fe being 1:1, measure and weigh 0.4612g of phosphoric acid and 1.1121g of ferrous sulfate hexahydrate, and dissolve them in the ascorbic acid solution prepared in step 2), stir for 10 minutes, and obtain For the solution of iron and ascorbic acid, ascorbic acid accounts for 15.8% of the target lithium iron phosphate mass, the concentration of phosphoric acid is 0.1mol / L, and the concentration of ferrous sulfate hexahydrate is 0.1mol / L.

[0025] 4) According to step 3) the amount of phosphoric acid taken by weighing, the molar ratio of Li and P is...

example 2

[0033] 1) Measure 40ml of ethylene glycol and 40ml of deionized water, and mix them to prepare a mixed solvent of ethylene glycol and water.

[0034] 2) Measure and weigh 0.063g of ascorbic acid and dissolve it in the mixed solvent of ethylene glycol and water prepared in step 1), and stir for 30 minutes to fully dissolve it.

[0035]3) According to the mol ratio of P and Fe being 1:1, measure and weigh 0.4612g of phosphoric acid and 1.1121g of ferrous sulfate hexahydrate, and dissolve them in the ascorbic acid solution prepared in step 2), stir for 10 minutes, and obtain For the solution of iron and ascorbic acid, ascorbic acid accounts for 10% of the target lithium iron phosphate mass, the concentration of phosphoric acid is 0.05mol / L, and the concentration of hexahydrate ferrous sulfate is 0.05mol / L.

[0036] 4) According to step 3) the amount of phosphoric acid taken by weighing, the molar ratio of Li and P is 3:1, measure and take lithium hydroxide 0.5035g, be dissolved i...

example 3

[0040] 1) Measure 20ml of ethylene glycol and 20ml of deionized water, and mix them to prepare a mixed solvent of ethylene glycol and water.

[0041] 2) Measure and weigh 0.189g of ascorbic acid and dissolve it in the mixed solvent of ethylene glycol and water prepared in step 1), and stir for 30 minutes to fully dissolve it.

[0042] 3) According to the mol ratio of P and Fe being 1:1, measure and weigh 0.4612g of phosphoric acid and 1.1121g of ferrous sulfate hexahydrate, and dissolve them in the ascorbic acid solution prepared in step 2), stir for 10 minutes, and obtain A solution of iron and ascorbic acid, ascorbic acid accounts for 30% of the target lithium iron phosphate mass, the concentration of phosphoric acid is 0.1mol / L, and the concentration of hexahydrate ferrous sulfate is 0.1mol / L.

[0043] 4) According to step 3) the amount of phosphoric acid taken by weighing, the molar ratio of Li and P is 3:1, measure and take lithium hydroxide 0.5035g, be dissolved in the m...

technical field

[0001] The invention relates to a preparation method of lithium iron phosphate single crystal nanorods, belonging to the fields of inorganic non-metallic materials and energy storage battery materials. Background technique

[0002] Lithium-ion battery, as a high-performance rechargeable green power source, has been widely used in various portable electronic products and communication tools in recent years, and has been gradually developed as a power source for electric vehicles, thereby promoting its development towards safety, environmental protection, Development in the direction of low cost and high specific energy. Among them, the development of new electrode materials, especially positive electrode materials, is extremely critical. At present, the widely studied cathode materials for lithium-ion batteries focus on transition metal oxides of lithium such as LiMO with a layered structure. 2 (M=Co, Ni, Mn) and LiMn with spinel structure 2 o 4 . However...

Examples

example 1

[0021] The preparation method comprises the following steps:

[0022] 1) Measure 20ml of ethylene glycol and 20ml of deionized water, and mix them to prepare a mixed solvent of ethylene glycol and water.

[0023] 2) Measure and weigh 0.1 g of ascorbic acid and dissolve it in the mixed solvent of ethylene glycol and water prepared in step 1), and stir for 30 minutes to fully dissolve it.

[0024] 3) According to the mol ratio of P and Fe being 1:1, measure and weigh 0.4612g of phosphoric acid and 1.1121g of ferrous sulfate hexahydrate, and dissolve them in the ascorbic acid solution prepared in step 2), stir for 10 minutes, and obtain For the solution of iron and ascorbic acid, ascorbic acid accounts for 15.8% of the target lithium iron phosphate mass, the concentration of phosphoric acid is 0.1mol / L, and the concentration of ferrous sulfate hexahydrate is 0.1mol / L.

[0025] 4) According to step 3) the amount of phosphoric acid taken by weighing, the molar ratio of Li and P is...

example 2

[0033] 1) Measure 40ml of ethylene glycol and 40ml of deionized water, and mix them to prepare a mixed solvent of ethylene glycol and water.

[0034] 2) Measure and weigh 0.063g of ascorbic acid and dissolve it in the mixed solvent of ethylene glycol and water prepared in step 1), and stir for 30 minutes to fully dissolve it.

[0035]3) According to the mol ratio of P and Fe being 1:1, measure and weigh 0.4612g of phosphoric acid and 1.1121g of ferrous sulfate hexahydrate, and dissolve them in the ascorbic acid solution prepared in step 2), stir for 10 minutes, and obtain For the solution of iron and ascorbic acid, ascorbic acid accounts for 10% of the target lithium iron phosphate mass, the concentration of phosphoric acid is 0.05mol / L, and the concentration of hexahydrate ferrous sulfate is 0.05mol / L.

[0036] 4) According to step 3) the amount of phosphoric acid taken by weighing, the molar ratio of Li and P is 3:1, measure and take lithium hydroxide 0.5035g, be dissolved i...

example 3

[0040] 1) Measure 20ml of ethylene glycol and 20ml of deionized water, and mix them to prepare a mixed solvent of ethylene glycol and water.

[0041] 2) Measure and weigh 0.189g of ascorbic acid and dissolve it in the mixed solvent of ethylene glycol and water prepared in step 1), and stir for 30 minutes to fully dissolve it.

[0042] 3) According to the mol ratio of P and Fe being 1:1, measure and weigh 0.4612g of phosphoric acid and 1.1121g of ferrous sulfate hexahydrate, and dissolve them in the ascorbic acid solution prepared in step 2), stir for 10 minutes, and obtain A solution of iron and ascorbic acid, ascorbic acid accounts for 30% of the target lithium iron phosphate mass, the concentration of phosphoric acid is 0.1mol / L, and the concentration of hexahydrate ferrous sulfate is 0.1mol / L.

[0043] 4) According to step 3) the amount of phosphoric acid taken by weighing, the molar ratio of Li and P is 3:1, measure and take lithium hydroxide 0.5035g, be dissolved in the m...

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