Lithium titanate composite material and preparation method and application thereof

Abstract

The invention provides a lithium titanate composite material and a preparation method and application thereof. The lithium titanate composite material comprises lithium titanate particles and lithium phosphate glass coated on the surface of the lithium titanate particles. The preparation method comprises the following steps of: uniformly mixing the lithium titanate particles and the mixture of a lithium source and a phosphorus source in a liquid system solvent to obtain uniformly-mixed liquid; performing ball milling on the uniformly-mixed liquid to form slurry; taking out the slurry and drying to obtain the precursor powder of the composite material; calcining the precursor powder of the composite material; and cooling and breaking to obtain the lithium titanate composite material of which the lithium phosphate glass is coated by the lithium titanate on the surface. The lithium titanate composite material is used as an active substance of a lithium ion battery or an electrode material of a capacitor. The lithium titanate composite material can suppress expansion of a lithium ion battery when applied to the lithium ion battery, improves the high-temperature storage and cycle performance of the lithium ion battery, increases the diffusion coefficient of lithium ions in the active substance, and is favorable for improving the rate capability of lithium titanate.

Description

technical field

[0001] The invention relates to the field of lithium ion batteries, in particular to a lithium titanate composite material, a preparation method thereof and an application thereof. Background technique

[0002] Lithium titanate is a zero-strain material. When it is used as the negative electrode active material of lithium-ion batteries, lithium-ion batteries have the characteristics of good cycle performance and long service life. Studies have found that when lithium titanate is used as the negative electrode active material, the cycle life of lithium-ion batteries at room temperature can reach more than 20,000 times, which makes lithium titanate have a good application prospect in lithium-ion batteries. In addition, the lithium-ion battery using lithium titanate as the negative electrode material (hereinafter referred to as "lithium titanate battery") also has the characteristics of stable discharge voltage and high voltage platform, and will not cause lithi...

Examples

preparation example Construction

[0023] According to the preparation method of lithium titanate composite material according to the second aspect of the present invention, it is used to prepare the lithium titanate composite material according to the first aspect of the present invention, comprising the step of: mixing lithium titanate particles with lithium source and phosphorus source The mixture is mixed in a liquid system solvent to obtain a mixed liquid; the mixed liquid is ball-milled to form a slurry, and then the slurry is taken out and dried to obtain the precursor powder of the composite material; the precursor of the composite material The bulk powder is calcined, and after cooling, it is crushed to obtain a lithium titanate composite material whose surface is covered with lithium phosphate glass.

[0024] Lithium titanate particles coated with lithium phosphate glass are used to isolate lithium titanate from the electrolyte. Lithium phosphate glass is a kind of Li 2 O and P 2 o 5 The eutectic me...

Embodiment 1

[0035] 500g particle size is 300nm lithium titanate particles, and the mixture of 2.150g lithium carbonate and 7.627g diammonium hydrogen phosphate (wherein the molar ratio of lithium element and phosphorus element is 0.5:0.5, wherein lithium carbonate and diammonium hydrogen phosphate Element and phosphorus corresponding to Li respectively 2 O and P 2 o 5 The mass ratio of the sum of the mass and the lithium titanate particles is 0.01:1) mixed in deionized water; after mixing evenly, ball milled on a ball mill for 6 hours to obtain a slurry; then the slurry was dried to obtain the precursor of lithium titanate composite material powder;

[0036] Put the precursor powder of lithium titanate composite material in a crucible, and then place it in a tube furnace for calcination at a constant temperature of 1000°C for 24 hours, and pulverize it after cooling to obtain lithium titanate particles coated with 0.5Li 2 O 0.5P 2 o 5 Lithium titanate composite material of lithium phos...

Embodiment 2

[0038] A mixture of 500g of lithium titanate particles with a particle size of 100nm, 1.200g of lithium hydroxide and 2.839g of ammonium dihydrogen phosphate (wherein the molar ratio of lithium to phosphorus is 0.67:0.33, wherein lithium hydroxide and ammonium dihydrogen phosphate Lithium element and phosphorus element respectively correspond to Li 2 O and P 2 o 5 The mass ratio of the sum of the mass of the lithium titanate particles to the lithium titanate particles is 0.005:1) and mixed in absolute ethanol; after mixing evenly, ball mill on a ball mill for 8 hours to obtain a slurry, and then dry the slurry to obtain the precursor of the lithium titanate composite material body powder;

[0039] Put the precursor powder of lithium titanate composite material in a crucible, and then place it in a tube furnace for calcination at a constant temperature of 1500°C for 2 hours, and then pulverize it after cooling to obtain lithium titanate particles coated with 0.67Li 2 O 0.33P...

technical field

[0001] The invention relates to the field of lithium ion batteries, in particular to a lithium titanate composite material, a preparation method thereof and an application thereof. Background technique

[0002] Lithium titanate is a zero-strain material. When it is used as the negative electrode active material of lithium-ion batteries, lithium-ion batteries have the characteristics of good cycle performance and long service life. Studies have found that when lithium titanate is used as the negative electrode active material, the cycle life of lithium-ion batteries at room temperature can reach more than 20,000 times, which makes lithium titanate have a good application prospect in lithium-ion batteries. In addition, the lithium-ion battery using lithium titanate as the negative electrode material (hereinafter referred to as "lithium titanate battery") also has the characteristics of stable discharge voltage and high voltage platform, and will not cause lithi...

Examples

preparation example Construction

[0023] According to the preparation method of lithium titanate composite material according to the second aspect of the present invention, it is used to prepare the lithium titanate composite material according to the first aspect of the present invention, comprising the step of: mixing lithium titanate particles with lithium source and phosphorus source The mixture is mixed in a liquid system solvent to obtain a mixed liquid; the mixed liquid is ball-milled to form a slurry, and then the slurry is taken out and dried to obtain the precursor powder of the composite material; the precursor of the composite material The bulk powder is calcined, and after cooling, it is crushed to obtain a lithium titanate composite material whose surface is covered with lithium phosphate glass.

[0024] Lithium titanate particles coated with lithium phosphate glass are used to isolate lithium titanate from the electrolyte. Lithium phosphate glass is a kind of Li 2 O and P 2 o 5 The eutectic me...

Embodiment 1

[0035] 500g particle size is 300nm lithium titanate particles, and the mixture of 2.150g lithium carbonate and 7.627g diammonium hydrogen phosphate (wherein the molar ratio of lithium element and phosphorus element is 0.5:0.5, wherein lithium carbonate and diammonium hydrogen phosphate Element and phosphorus corresponding to Li respectively 2 O and P 2 o 5 The mass ratio of the sum of the mass and the lithium titanate particles is 0.01:1) mixed in deionized water; after mixing evenly, ball milled on a ball mill for 6 hours to obtain a slurry; then the slurry was dried to obtain the precursor of lithium titanate composite material powder;

[0036] Put the precursor powder of lithium titanate composite material in a crucible, and then place it in a tube furnace for calcination at a constant temperature of 1000°C for 24 hours, and pulverize it after cooling to obtain lithium titanate particles coated with 0.5Li 2 O 0.5P 2 o 5 Lithium titanate composite material of lithium phos...

Embodiment 2

[0038] A mixture of 500g of lithium titanate particles with a particle size of 100nm, 1.200g of lithium hydroxide and 2.839g of ammonium dihydrogen phosphate (wherein the molar ratio of lithium to phosphorus is 0.67:0.33, wherein lithium hydroxide and ammonium dihydrogen phosphate Lithium element and phosphorus element respectively correspond to Li 2 O and P 2 o 5 The mass ratio of the sum of the mass of the lithium titanate particles to the lithium titanate particles is 0.005:1) and mixed in absolute ethanol; after mixing evenly, ball mill on a ball mill for 8 hours to obtain a slurry, and then dry the slurry to obtain the precursor of the lithium titanate composite material body powder;

[0039] Put the precursor powder of lithium titanate composite material in a crucible, and then place it in a tube furnace for calcination at a constant temperature of 1500°C for 2 hours, and then pulverize it after cooling to obtain lithium titanate particles coated with 0.67Li 2 O 0.33P...

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