阅读说明：本技术 一种用于制备锂电池负极材料的钛酸锂及制备方法和应用 (Lithium titanate for preparing lithium battery negative electrode material, preparation method and application ) 是由 张云 王倩 吴昊 王国传 马光强 于 2020-12-21 设计创作，主要内容包括：一种用于制备锂电池负极材料的钛酸锂及制备方法和应用,涉及锂离子电池的负极材料制备技术领域。所述钛酸锂通过调控酸化处理的偏钛酸与锂源的比例,碳源的添加量和种类,将偏钛酸,锂源,碳源,混合均匀后,经煅烧后得到优良性能的钛酸锂。在钛酸锂颗粒表面包覆一层碳层有利于提高颗粒表面的电子导电性,表面包覆碳层这种改性方法得到具有优异循环和倍率性能的钛酸锂负极材料,且制备方法简单,成本低廉,绿色环保。(A lithium titanate for preparing a negative electrode material of a lithium battery, a preparation method and an application relate to the technical field of preparation of the negative electrode material of the lithium battery. The lithium titanate is prepared by uniformly mixing metatitanic acid, a lithium source and a carbon source and calcining the mixture after regulating the proportion of the metatitanic acid to the lithium source subjected to acidification treatment and the addition amount and the type of the carbon source. The carbon layer is coated on the surface of the lithium titanate particle, so that the electronic conductivity of the particle surface is improved, the lithium titanate anode material with excellent cycle and rate performance is obtained by the modification method of coating the carbon layer on the surface, and the preparation method is simple, low in cost and environment-friendly.)

1. A preparation method of lithium titanate is characterized by comprising the following steps:

(1) adding metatitanic acid into concentrated sulfuric acid, stirring to form a suspension, washing the acidified metatitanic acid with deionized water, filtering and drying;

(2) adding water into a carbon source and the metatitanic acid after acid treatment, mixing uniformly, and drying to form a precursor;

(3) uniformly mixing a lithium source and a precursor in proportion;

(4) the heat preservation is carried out for 2 hours in 500 ℃ inert gas, and then the sintering is carried out for 6 to 8 hours at the temperature of 650 to 800 ℃.

2. The preparation method according to claim 1, wherein in the step (1), the mass ratio of the concentrated sulfuric acid to the metatitanic acid is 1: 7 to 10.

3. The method according to claim 1, wherein the time period of the acidification treatment in the step (1) is 1 to 24 hours.

4. The preparation method according to claim 1, wherein in the step (1), the mass ratio of deionized water to metatitanic acid is 1: 10.

5. the method according to claim 1, wherein in the step (2), the carbon source is one of glucose, sucrose or citric acid, and is added in an amount of 6 to 9% by mass based on the total mass of the lithium source and metatitanic acid.

6. The method according to claim 1, wherein in the step (3), the lithium source is one or more of lithium carbonate, lithium acetate, lithium hydroxide and lithium nitrate.

7. The production method according to claim 1, wherein in the step (3), the mass ratio of the lithium element to the titanium element is 1:0.8 to 0.85.

8. The method according to claim 1, wherein in the step (4), the inert gas is nitrogen and/or argon.

9. A lithium titanate for preparing a negative electrode material of a lithium battery, which is prepared by the preparation method of any one of claims 1 to 8.

10. Use of the lithium titanate as claimed in claim 9 for the preparation of negative electrode materials for lithium batteries in negative electrode materials for lithium batteries.

Technical Field

The invention relates to the technical field of preparation of negative electrode materials of lithium ion batteries, in particular to lithium titanate for preparing a negative electrode material of a lithium battery, and a preparation method and application thereof.

Background

At present, a solid-phase method is usually adopted for preparing lithium titanate, and a titanium source usually adopted for preparing lithium titanate by the solid-phase method is titanium dioxide, and the method has the defects that the crystal lattice of the titanium dioxide is complete, and the activation energy required for lithium ions to diffuse into the crystal lattice is larger in the sintering process, so that a TiO2 impurity phase is generated during sintering at a lower temperature, and the existence of a TiO2 phase can cause the gas generation of a lithium titanate negative electrode material in the charging and discharging processes, so that the cycle performance is deteriorated. When the sintering temperature is higher, lithium titanate particles are increased in the sintering process, and lithium ions are increased by using lithium titanate with larger particles as an electrode material.

In view of this, the present application is specifically made.

Disclosure of Invention

The first purpose of the invention is to provide a preparation method of lithium titanate, which is simple and convenient to operate, and not only is the prepared lithium titanate excellent in performance, but also the cost of labor and equipment can be effectively reduced.

The second purpose of the invention is to provide a lithium titanate for preparing a negative electrode material of a lithium battery, wherein a titanium source adopted by the lithium titanate is metatitanic acid (H2TiO3), the metatitanic acid has the same crystal structure of titanium dioxide but poor crystallinity, the crystal structure of the metatitanic acid after acid treatment and etching is increased in disorder degree, and lithium ions are easy to enter crystal lattices at a lower sintering temperature and then are coordinated to form Li4Ti5O12 particles with smaller particle sizes. Sintering at low temperature can generate smaller lithium titanate particles, and the diffusion distance of lithium ions is shortened in the charge-discharge process; after the carbon layer is coated on the surface of lithium titanate, the conductivity among negative electrode material particles is improved, and the multiplying power and the cycle performance of lithium titanate as a negative electrode material are improved.

The third purpose of the invention is to provide the application of the lithium titanate for preparing the negative electrode material of the lithium battery in the negative electrode material of the lithium battery.

The embodiment of the invention is realized by the following steps:

a preparation method of lithium titanate comprises the following steps:

(1) adding metatitanic acid into concentrated sulfuric acid, stirring to form a suspension, washing the acidified metatitanic acid with deionized water, filtering and drying;

(2) adding water into a carbon source and the metatitanic acid after acid treatment, mixing uniformly, and drying to form a precursor;

(3) uniformly mixing a lithium source and a precursor in proportion;

(4) the heat preservation is carried out for 2 hours in 500 ℃ inert gas, and then the sintering is carried out for 6 to 8 hours at the temperature of 650 to 800 ℃.

Further, in the step (1), the mass ratio of the concentrated sulfuric acid to the metatitanic acid is 1: 7 to 10.

Further, in the step (1), the time period of the acidification treatment is 1-24 hours.

Further, in the step (1), the mass ratio of the deionized water to the metatitanic acid is 1: 10

Further, in the step (2), the carbon source is one of glucose, sucrose or citric acid, and the adding amount of the carbon source is 6-9% of the total mass of the lithium source and the metatitanic acid.

Further, in the step (3), the lithium source is one or more of lithium carbonate, lithium acetate, lithium hydroxide and lithium nitrate.

Further, in the step (3), the mass ratio of the lithium element to the titanium element is 1: 0.8-0.85.

Further, in the step (4), the inert gas is nitrogen and/or argon.

A lithium titanate for preparing a lithium battery cathode material is prepared by adopting the method for preparing the lithium titanate.

An application of lithium titanate for preparing a lithium battery cathode material in the lithium battery cathode material.

The embodiment of the invention has the beneficial effects that:

the preparation method of the lithium titanate provided by the embodiment of the invention is simple and convenient to operate, and not only is the prepared lithium titanate excellent in performance, but also the cost of labor and equipment can be effectively reduced. The titanium source of the lithium titanate prepared by the preparation method is metatitanic acid (H2TiO3), the titanium source has the same crystal structure of titanium dioxide but poor crystallinity, the crystal structure of the metatitanic acid etched by acid treatment is increased in disorder degree, and lithium ions are easy to enter crystal lattices at lower sintering temperature and then coordinate to form Li4Ti5O12 particles with smaller particle size. Sintering at low temperature can generate smaller lithium titanate particles, and the diffusion distance of lithium ions is shortened in the charge-discharge process; after the carbon layer is coated on the surface of lithium titanate, the conductivity among negative electrode material particles is improved, and the multiplying power and the cycle performance of lithium titanate as a negative electrode material are improved. Can be well applied to the preparation of the lithium battery cathode material.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

FIG. 1 is a comparative graph of charge and discharge curves of samples provided by examples of the present invention;

FIG. 2 is a graph comparing magnification provided by the embodiment of the present invention;

FIG. 3 is a comparison graph of the cycle provided by the embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings or the orientations or positional relationships that the products of the present invention are conventionally placed in use, and are only used for convenience in describing the present invention and simplifying the description, but do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," "third," and the like are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance.

Furthermore, the terms "parallel," "perpendicular," and the like do not require that the components be absolutely parallel or perpendicular, but may be slightly inclined. For example, "parallel" merely means that the directions are more parallel relative to "perpendicular," and does not mean that the structures are necessarily perfectly parallel, but may be slightly tilted.

Furthermore, the terms "horizontal", "vertical", "overhang" and the like do not imply that the components are required to be absolutely horizontal or overhang, but may be slightly inclined. For example, "horizontal" merely means that the direction is more horizontal than "vertical" and does not mean that the structure must be perfectly horizontal, but may be slightly inclined.

The terms "substantially", "essentially", and the like are intended to indicate that the relative terms are not required to be absolutely exact, but may have some deviation. For example: "substantially equal" does not mean absolute equality, but it is difficult to achieve absolute equality in actual production and operation, and some deviation generally exists. Thus, in addition to absolute equality, "substantially equal" also includes the above-described case where there is some deviation. In this case, unless otherwise specified, terms such as "substantially", and the like are used in a similar manner to those described above.

Examples

The embodiment provides a preparation method of lithium titanate, which comprises the following steps:

(1) adding industrial metatitanic acid into a certain amount of concentrated sulfuric acid for acid treatment, wherein the mass ratio of the concentrated sulfuric acid to the metatitanic acid is 1: 10; stirring to form a suspension, washing the metatitanic acid which is acidized for 1-24 hours by a certain amount of deionized water, filtering and drying; wherein the mass ratio of the deionized water to the metatitanic acid used for washing is 1: 10;

(2) and (3) adding a certain amount of water into the carbon source and the metatitanic acid after acid treatment, mixing uniformly, and drying to form a precursor. Wherein the carbon source is one of glucose, sucrose and citric acid, preferably glucose, and the adding amount of the carbon source is 6-9% of the total mass of the lithium source and the metatitanic acid;

(3) uniformly mixing a lithium source and a precursor in proportion; wherein the lithium source is one or more of lithium carbonate, lithium acetate, lithium hydroxide and lithium nitrate, and cheap lithium carbonate is preferred; in addition, the mass ratio of the lithium element to the titanium element is 1: 0.8-0.85; preferably 1: 0.83;

(4) firstly, preserving heat in 500 ℃ inert gas for 2 hours, and then sintering at 650-800 ℃ for 6-8 hours; wherein the inert gas is one or more of nitrogen or argon; the heating rate is 3-5 ℃/min.

In general, the method for preparing carbon-coated lithium titanate provided by the embodiment is simple and convenient to operate, and not only is the prepared lithium titanate excellent in performance, but also the cost of labor and equipment can be effectively reduced.

Example 1

The embodiment provides lithium titanate for preparing a lithium battery negative electrode material, which is prepared by the following steps:

(1) adding industrial metatitanic acid into a certain amount of concentrated sulfuric acid for acid treatment, wherein the mass ratio of the concentrated sulfuric acid to the metatitanic acid is 1: 10; stirring to form a suspension, washing the metatitanic acid after acidification for 12 hours by using a certain amount of deionized water, filtering and drying; wherein the mass ratio of the deionized water to the metatitanic acid used for washing is 1: 10;

(2) mixing glucose accounting for 9% of the total mass of the lithium source and the metatitanic acid after acid treatment with a certain amount of water, uniformly mixing, and drying to form a precursor; wherein the drying temperature is 60 ℃, and the drying time is 30 minutes;

(3) uniformly mixing lithium carbonate and a precursor according to the mass ratio of lithium element to titanium element of 1: 0.8;

(4) firstly, preserving heat for 2 hours in argon at 500 ℃, and then sintering for 6-8 hours at 650-800 ℃; the heating rate is 3-5 ℃/min.

Example 2

The embodiment provides lithium titanate for preparing a lithium battery negative electrode material, which is prepared by the following steps:

(1) adding industrial metatitanic acid (H2TiO3) into a certain amount of concentrated sulfuric acid for acid treatment, wherein the mass ratio of the concentrated sulfuric acid to the metatitanic acid is 1: 10; stirring to form a suspension, washing the metatitanic acid after acidification for 12 hours by using a certain amount of deionized water, filtering and drying; wherein the mass ratio of the deionized water to the metatitanic acid used for washing is 1: 10; in addition, the drying temperature is 60 ℃, and the drying time is 12 hours;

(2) mixing glucose accounting for 9% of the total mass of the lithium source and the metatitanic acid after acid treatment with a certain amount of water, uniformly mixing, and drying to form a precursor; wherein the drying temperature is 60 ℃, and the drying time is 30 minutes;

(3) uniformly mixing lithium carbonate and a precursor according to the mass ratio of lithium element to titanium element of 1: 0.83;

(4) firstly, preserving heat for 2 hours in argon at 500 ℃, and then sintering for 6-8 hours at 650-800 ℃; the heating rate is 3-5 ℃/min.

Example 3

The embodiment provides lithium titanate for preparing a lithium battery negative electrode material, which is prepared by the following steps:

(1) adding industrial metatitanic acid (H2TiO3) into a certain amount of concentrated sulfuric acid for acid treatment, wherein the mass ratio of the concentrated sulfuric acid to the metatitanic acid is 1: 10; stirring to form a suspension, washing the metatitanic acid after acidification for 12 hours by using a certain amount of deionized water, filtering and drying; wherein the mass ratio of the deionized water to the metatitanic acid used for washing is 1: 10; in addition, the drying temperature is 60 ℃, and the drying time is 12 hours;

(2) mixing glucose accounting for 6% of the total mass of the lithium source and the metatitanic acid after acid treatment with a certain amount of water, uniformly mixing, and drying to form a precursor; wherein the drying temperature is 60 ℃, and the drying time is 30 minutes;

(3) uniformly mixing lithium carbonate and a precursor according to the mass ratio of lithium element to titanium element of 1: 0.83;

(4) firstly, preserving heat for 2 hours in argon at 500 ℃, and then sintering for 6-8 hours at 650-800 ℃; the heating rate is 3-5 ℃/min.

Example 4

The embodiment provides lithium titanate for preparing a lithium battery negative electrode material, which is prepared by the following steps:

(1) adding industrial metatitanic acid (H2TiO3) into a certain amount of concentrated sulfuric acid for acid treatment, wherein the mass ratio of the concentrated sulfuric acid to the metatitanic acid is 1: 10; stirring for 18 hours to form a suspension, washing the acidified metatitanic acid with a certain amount of deionized water, filtering and drying; wherein the mass ratio of the deionized water to the metatitanic acid used for washing is 1: 10; in addition, the drying temperature is 60 ℃, and the drying time is 12 hours;

(2) mixing glucose accounting for 6% of the total mass of the lithium source and the metatitanic acid after acid treatment with a certain amount of water, uniformly mixing, and drying to form a precursor; wherein the drying temperature is 60 ℃, and the drying time is 30 minutes;

(3) uniformly mixing lithium carbonate and a precursor according to the mass ratio of lithium element to titanium element of 1: 0.83;

(4) firstly, preserving heat for 2 hours in argon at 500 ℃, and then sintering for 6-8 hours at 650-800 ℃; the heating rate is 3-5 ℃/min.

Comparative example

The negative electrode material for lithium battery of this comparative example was prepared by mixing and sintering the same metatitanic acid, lithium source and glucose in the above ratio as in the above example but without acid treatment, and specifically, the nickel-based multi-element positive electrode material of the comparative example was prepared by the following steps:

adding a certain amount of water into metatitanic acid and glucose which account for 6% of the total mass of the lithium source and the titanium source, uniformly mixing, and drying to form a precursor, wherein the metatitanic acid which is not subjected to acid treatment is used as the titanium source, the lithium carbonate is used as the lithium source, the drying temperature is 60 ℃, and the drying time is 30 minutes;

uniformly mixing lithium carbonate and the dried metatitanic acid precursor according to the mass ratio of Li element to Ti element of 0.83;

and (3) in an argon atmosphere, firstly, preserving heat at 500 ℃ for 2 hours, and then sintering at 650-800 ℃ for 6-8 hours to obtain the carbon-coated lithium titanate, wherein the heating rate is 3-5 ℃/min.

The composition of the two samples was determined by XRD testing; the performance of the lithium titanate obtained in the above example 3 and comparative example is tested through experiments, and the specific method is that the lithium titanate is adopted to assemble a button cell, the battery is charged and discharged at 0.1C under the test conditions of 1-2.5V at 25 ± 5 ℃ and 30-60% of humidity at 25 ± 5 ℃ to obtain the charge and discharge curve of the lithium titanate, and the battery is charged and discharged at 5C to simulate the cycle charge and discharge performance of the battery used for a long time.

Referring to fig. 1-3, it can be seen from the above data that the lithium titanate prepared by using the acidified industrial metatitanic acid as a raw material has excellent cycle and rate performance. XRD showed that the lithium titanate in example 3 was a pure phase, whereas the comparative example had the hetero-phase TiO2, the presence of which would affect the cycle performance deterioration.

In summary, the method for preparing carbon-coated lithium titanate provided by the embodiment of the invention is simple and convenient to operate, and the prepared lithium titanate product has excellent performance and can effectively reduce the cost of labor and equipment. The titanium source of the lithium titanate prepared by the preparation method is metatitanic acid (H2TiO3), the titanium source has the same crystal structure of titanium dioxide but poor crystallinity, the crystal structure of the metatitanic acid etched by acid treatment is increased in disorder degree, and lithium ions are easy to enter crystal lattices at lower sintering temperature and then coordinate to form Li4Ti5O12 particles with smaller particle size. Sintering at low temperature can generate smaller lithium titanate particles, and the diffusion distance of lithium ions is shortened in the charge-discharge process; after the carbon layer is coated on the surface of lithium titanate, the conductivity among negative electrode material particles is improved, and the multiplying power and the cycle performance of lithium titanate as a negative electrode material are improved. Can be well applied to the preparation of the lithium battery cathode material.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.