Lithium titanate/lithium ion conductor/carbon composite material and preparation method and application thereof

Abstract

The invention belongs to the technical field of battery materials, and particularly relates to a lithium titanate / lithium ion conductor / carbon composite material, a preparation method thereof and a secondary battery. The lithium titanate / lithium ion conductor / carbon composite material sequentially comprises a lithium titanate inner core, a lithium ion conductor middle layer and a carbon material shell layer from inside to outside. According to the lithium titanate / lithium ion conductor / carbon composite material, through the synergistic effect of the lithium titanate inner core, the lithium ion conductor middle layer and the carbon material shell layer, the composite material has the characteristics of being not prone to flatulence, excellent in electron / ion transmission performance, good in high and low temperature characteristics, good in structural stability, excellent in fast charging performance, high in safety and the like.

Description

technical field

[0001] The application belongs to the technical field of battery materials, and in particular relates to a lithium titanate / lithium ion conductor / carbon composite material and a preparation method thereof, and a secondary battery. Background technique

[0002] In recent years, due to the advantages of high energy density, good cycle performance, no memory effect and light weight, lithium-ion batteries have been widely used in portable electronic devices, electric vehicles and other fields, and gradually expanded to large-scale energy storage and other fields. At present, graphite is the main anode material for commercial lithium-ion batteries, but it needs to be improved in terms of cycle life, rate performance, low-temperature performance, and safety hazards caused by lithium dendrites. Compared with the traditional graphite anode, lithium titanate (Li 4 Ti 5 o 12 ) has a three-dimensional lithium ion diffusion channel, and the lattice constant of lithium...

Examples

preparation example Construction

[0036] The second aspect of the embodiment of the present application provides a preparation method of lithium titanate / lithium ion conductor / carbon composite material, comprising the following steps:

[0037] Dissolving the lithium source and other source compounds in a solvent, adding a complexing agent for thermal mixing reaction, to obtain a lithium ion conductor precursor;

[0038] Lithium titanate is mixed with the lithium ion conductor precursor solution, then a precipitant is added for precipitation, and the co-precipitated substance is separated;

[0039] Calcining the co-precipitated material under an inert atmosphere to obtain a lithium titanate / lithium ion conductor composite material, wherein the lithium ion conductor is coated on the outer surface of the lithium titanate;

[0040] After mixing the lithium titanate / lithium ion conductor composite material and the solution of the carbon material, drying treatment and low temperature heat treatment are carried out i...

Embodiment 1

[0076] A kind of lithium titanate / lithium ion conductor / graphene composite material, its preparation comprises steps:

[0077] ① Preparation of lithium ion conductor NASICON type lithium germanium aluminum phosphate (Li 1.6 Al 0.6 Ge 0.8 (PO 4 ) 3 ) precursor solution:

[0078] Dissolve lithium nitrate, aluminum nitrate, germanium methoxide, and ammonium dihydrogen phosphate in an appropriate amount of deionized water at a molar ratio of 1.6:0.6:0.8:3, wherein the molar concentration of lithium nitrate is 0.1mol / L. Add an aqueous citric acid solution that is 4 times the molar ratio of lithium ions and germanium ions in the solution, adjust the pH of the solution to 5, and continue stirring at 80°C for 6 hours to obtain the lithium ion conductor Li 1.6 Al 0.6 Ge 0.8 (PO 4 ) 3 precursor solution.

[0079] ② Preparation of lithium germanium aluminum phosphate / lithium titanate composite material:

[0080] Add lithium titanate with a size of 200nm to the prepared lithium...

Embodiment 2～3

[0093] Embodiment 2-3 Compared with embodiment 1, except that the lithium ion conductor type used when preparing lithium titanate / germanium aluminum phosphate / graphene composite material is different (specifically as shown in the following table 1), other materials, steps all the same.

technical field

[0001] The application belongs to the technical field of battery materials, and in particular relates to a lithium titanate / lithium ion conductor / carbon composite material and a preparation method thereof, and a secondary battery. Background technique

[0002] In recent years, due to the advantages of high energy density, good cycle performance, no memory effect and light weight, lithium-ion batteries have been widely used in portable electronic devices, electric vehicles and other fields, and gradually expanded to large-scale energy storage and other fields. At present, graphite is the main anode material for commercial lithium-ion batteries, but it needs to be improved in terms of cycle life, rate performance, low-temperature performance, and safety hazards caused by lithium dendrites. Compared with the traditional graphite anode, lithium titanate (Li 4 Ti 5 o 12 ) has a three-dimensional lithium ion diffusion channel, and the lattice constant of lithium...

Examples

preparation example Construction

[0036] The second aspect of the embodiment of the present application provides a preparation method of lithium titanate / lithium ion conductor / carbon composite material, comprising the following steps:

[0037] Dissolving the lithium source and other source compounds in a solvent, adding a complexing agent for thermal mixing reaction, to obtain a lithium ion conductor precursor;

[0038] Lithium titanate is mixed with the lithium ion conductor precursor solution, then a precipitant is added for precipitation, and the co-precipitated substance is separated;

[0039] Calcining the co-precipitated material under an inert atmosphere to obtain a lithium titanate / lithium ion conductor composite material, wherein the lithium ion conductor is coated on the outer surface of the lithium titanate;

[0040] After mixing the lithium titanate / lithium ion conductor composite material and the solution of the carbon material, drying treatment and low temperature heat treatment are carried out i...

Embodiment 1

[0076] A kind of lithium titanate / lithium ion conductor / graphene composite material, its preparation comprises steps:

[0077] ① Preparation of lithium ion conductor NASICON type lithium germanium aluminum phosphate (Li 1.6 Al 0.6 Ge 0.8 (PO 4 ) 3 ) precursor solution:

[0078] Dissolve lithium nitrate, aluminum nitrate, germanium methoxide, and ammonium dihydrogen phosphate in an appropriate amount of deionized water at a molar ratio of 1.6:0.6:0.8:3, wherein the molar concentration of lithium nitrate is 0.1mol / L. Add an aqueous citric acid solution that is 4 times the molar ratio of lithium ions and germanium ions in the solution, adjust the pH of the solution to 5, and continue stirring at 80°C for 6 hours to obtain the lithium ion conductor Li 1.6 Al 0.6 Ge 0.8 (PO 4 ) 3 precursor solution.

[0079] ② Preparation of lithium germanium aluminum phosphate / lithium titanate composite material:

[0080] Add lithium titanate with a size of 200nm to the prepared lithium...

Embodiment 2～3

[0093] Embodiment 2-3 Compared with embodiment 1, except that the lithium ion conductor type used when preparing lithium titanate / germanium aluminum phosphate / graphene composite material is different (specifically as shown in the following table 1), other materials, steps all the same.

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