Patent Application
20200083528
This application claims the benefit of and priority to Chinese Patent Application No. 201811038606.9, filed Sep. 6, 2018, which is incorporated herein by reference in its entirety.
The invention relates to the field of energy, and in particular, to a linear hierarchical structure lithium titanate material, preparation and application thereof.
As an ideal and promising negative electrode material for lithium-ion battery, lithium titanate may have a charge-discharge cycle number up to thousands, and thus become a hot spot in the field of electrode material research.
The use of lithium titanate in lithium-ion battery may be influenced largely by its size and morphology. For example, a hierarchical structure material can well preserve the microstructural function of the material while sufficiently making use of the nanostructure properties of the material. The components of the hierarchical structure material are generally small nanoparticles, which can increase the specific surface area of the material and improve the nanoscale performances of the material; the hierarchical structure material is in micron scale as a whole, which is beneficial to the accumulation between whole particles, and can greatly improve the rapid charge and discharge performance of the battery. In addition, as compared with the particles, the linear structure lithium titanate material can reduce the grain boundary between the particles and facilitate the transport of carriers in the long-axis direction. In the field of electrode materials for battery, the long axis may facilitate the effective migration of electrons and the short axis may facilitate the rapid intercalation and deintercalation of lithium, sodium or potassium ions. The linear structure has better charge-discharge performance and the like than the particulates. Therefore, the linear hierarchical structure lithium titanate material can greatly improve the specific surface area of the material, enhance the surface activity of the material, reduce grain boundaries between the particles and improve the effective transport of carriers in the long-axis direction, which can greatly improve the application performance of the material in a battery electrode in terms of capacity and rapid charge-discharge.
The existing methods for producing lithium titanate mainly include solid state synthesis and hydrothermal reaction preparation. Among them, the solid state synthesis method generally includes, firstly mixing well raw materials such as lithium hydroxide or lithium carbonate and titanium oxide by means of ball milling or in an organic solvent, and then sintering the resultant at a high temperature of more than 800° C. to obtain lithium titanate. The preparation method requires an excess of lithium hydroxide or lithium carbonate, and the obtained lithium titanate generally has a low purity, a size of micron scale, and poor morphology and uniformity. The hydrothermal preparation method for lithium titanate usually involves: producing sodium titanate by a hydrothermal process using commercial titanium oxide and sodium hydroxide as starting materials, and immersing sodium titanate into an acid solution to obtain titanic acid by ion exchange; and then mixing the titanic acid with a lithium hydroxide solution or a lithium titanate precursor followed by annealing the product at different temperatures to obtain the lithium titanate product. The hydrothermal process in the preparation method involves a high temperature and a high pressure, which is dangerous to some extent. Meanwhile, the reaction system is a strong alkali of 10 mol/L, which is highly corrosive at high temperatures. Thus, it has a harsh requirement for hydrothermal reaction apparatus, and it may be difficult to find a suitable reaction apparatus. In addition, the preparation method uses an alkali at a high concentration, which makes the subsequent product separation and purification difficult, and also brings pollution to the environment. Therefore, the hydrothermal preparation method for lithium titanate still faces many difficulties in the synthesis apparatus and subsequent processing, and the mass production cannot be realized.
To sum up, in order to further improve the application performance of lithium titanate materials in the field of lithium-ion battery, it is urgent to develop a lithium titanate electrode material having a linear hierarchical structure. In addition, the development of a method for producing lithium titanate having a simple technological process and easy for large-scale production, especially a method for producing a lithium titanate material having a linear hierarchical structure, still faces great technical challenges.
It is an object of the disclosure to provide a linear hierarchical structure lithium titanate material.
It is another object of the disclosure to provide a method for preparing the linear hierarchical structure lithium titanate material.
It is still another object of the disclosure to provide an electrode material for an ion battery.
In order to achieve the above objects, in one aspect, the disclosure provides a linear hierarchical structure lithium titanate material, wherein the crystal phase of the lithium titanate material is a spinel-type crystal phase or a monoclinic crystal phase or a composite crystal phase thereof; the lithium titanate material is mainly composed of a linear hierarchical structure; and the surface components of the linear hierarchical structure lithium titanate material are nanosheets.
According to some specific embodiments, the surface of the linear hierarchical structure lithium titanate material is further loaded with one or more selected from the group consisting of carbon, carbon nanotubes, graphene, black phosphorus, metals, and semiconductors.
According to some specific embodiments, the linear hierarchical structure has an aspect ratio greater than 10.
According to some specific embodiments, the linear hierarchical structure has an aspect ratio of 10 to 100.
According to some specific embodiments, the linear hierarchical structure is a solid linear structure or a hollow linear structure.
According to some specific embodiments, the linear hierarchical structure has a diameter of 20 nm to 1 μm and a length of 1 μm to 50 μm.
According to some specific embodiments, the linear hierarchical structure has a diameter of 50 nm to 500 nm and a length of 5 μm to 20 μm.
According to some specific embodiments, the nanosheets have a size of 5 nm to 300 nm.
According to some specific embodiments, the nanosheets have a size of 10 nm to 100 nm.
According to some specific embodiments, the nanosheets have a thickness of 1 nm to 20 nm.
According to some specific embodiments, the nanosheets have a thickness of 1 nm to 10 nm.
According to some specific embodiments, the method for preparing the linear hierarchical structure lithium titanate material comprises the following steps:
(1) preparing a linear structure lithium peroxotitanate;
(2) subjecting the linear structure lithium peroxotitanate obtained in the step (1) to a hydrothermal reaction or a solvothermal reaction to obtain a linear hierarchical structure lithium titanate precursor;
(3) subjecting the linear hierarchical structure lithium titanate precursor obtained in the step (2) to an annealing treatment to obtain the linear hierarchical structure lithium titanate material.
According to some specific embodiments, the method further comprises preparing a linear structure lithium peroxotitanate, comprising the followings steps:
(a1) preparing a dispersion containing titanium peroxo-complex;
(b1) adding a lithium compound into the dispersion containing titanium peroxo-complex obtained in the step (a1) to form a solution;
(c1) subjecting the solution obtained in the step (b1) to a reaction under heating to obtain the linear structure lithium peroxotitanate;
or, comprising the followings steps:
(a2) subjecting a titanium source to a hydrolysis reaction to form a hydrated titanic acid precipitate;
(b2) dispersing the hydrated titanic acid precipitate obtained in the step (a2) in an aqueous hydrogen peroxide solution containing lithium hydroxide, and stirring to form a solution;
(c2) subjecting the solution obtained in the step (b2) to a reaction under heating to obtain the linear structure lithium peroxotitanate.
According to some specific embodiments, the method further comprises subjecting the linear structure lithium peroxotitanate obtained in the step (c1) and the step (c2) to a low-temperature treatment for decomposition and removal of peroxy on the surface of the linear structure lithium peroxotitanate, to obtain a linear structure lithium peroxotitanate having peroxy removed on the surface thereof.
According to some specific embodiments, the low-temperature treatment is carried out at a temperature of 120° C. to 200° C. for 1 h to 12 h.
According to some specific embodiments, the system of the hydrothermal reaction is selected from a pure water system, an acidic water system or an alkaline water system; and the hydrothermal reaction is carried out at a temperature of 100° C. to 150° C. for 1 h to 24 h.
It is understood that the pure water system refers to a neutral water system, that is, water having a neutral pH, such as deionized water, domestic water, industrial water, etc.
According to some specific embodiments, the system of the solvothermal reaction is selected from an aqueous alcohol solution system or an alcohol solution system; and the solvothermal reaction is carried out at a temperature of 80° C. to 150° C. for 1 h to 24 h.
According to some specific embodiments, the annealing treatment is carried out at a temperature of 300° C. to 700° C. for 1 h to 24 h.
According to some specific embodiments, the titanium peroxo-complex in the dispersion containing titanium peroxo-complex has a concentration of 0.01 mol/L to 1 mol/L.
According to some specific embodiments, the titanium peroxo-complex in the dispersion containing titanium peroxo-complex has a concentration of 0.05 mol/L to 0.5 mol/L.
According to some specific embodiments, the method further comprises the preparation process of a dispersion containing titanium peroxo-complex, comprising the step of: dispersing a titanium compound into an aqueous peroxide solution to form a dispersion, to obtain the dispersion containing titanium peroxo-complex.
According to some specific embodiments, the titanium compound is selected from one or more of metallic titanium, titanium ethoxide, titanium isopropoxide, tetrabutyl titanate, titanium glycolate, titanium glyceroxide, titanium sulfate, titanium oxysulfate, titanium tetrachloride, titanium tetrafluoride, ammonium fluorotitanate, titanium nitride, titanium oxide, and titanic acid.
According to some specific embodiments, the peroxide is selected from one or more of hydrogen peroxide, urea peroxide and peracetic acid.
According to some specific embodiments, the method further comprises, after dispersing a titanium compound into a peroxide aqueous solution to form a dispersion, adding a polymer into the dispersion to obtain the dispersion containing titanium peroxo-complex.
According to some specific embodiments, the polymer is selected from one or more of chitosan, guar, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, polyvinyl alcohol, polyacrylamide, polyethylene oxide, polyethylene glycol, and polyvinylpyrrolidone.
According to some specific embodiments, the polymer is added in an amount such that the content of the polymer in the obtained dispersion containing titanium peroxo-complex is 0.01% to 10% by mass.
According to some specific embodiments, the polymer is added in an amount such that the content of the polymer in the obtained dispersion containing titanium peroxo-complex is 0.1% to 10% by mass.
According to some specific embodiments, the lithium compound is selected from one or more of lithium hydroxide, lithium oxide, lithium peroxide, and lithium superoxide.
According to some specific embodiments, the lithium compound is used in an amount such that the concentration of lithium ions in the solution formed by adding the lithium compound is 0.4 mol/L to 2.0 mol/L.
According to some specific embodiments, in the step (c1) and the step (c2), the reaction under heating is independently carried out at a temperature of 60° C. to 100° C. for 0.5 h to 24 h.
According to some specific embodiments, the titanium source is selected from one or more of titanium ethoxide, titanium isopropoxide, tetrabutyl titanate, titanium glycolate, titanium glyceroxide, titanium sulfate, titanium oxysulfate, titanium tetrachloride, titanium tetrafluoride, ammonium fluorotitanate, titanium nitride, titanic acid, and industrial titanium-containing compounds.
According to some specific embodiments, in the step (a2), the hydrolysis reaction comprises dispersing the titanium source in water for hydrolysis to produce a hydrated titanic acid precipitate, or, the hydrolysis reaction comprises dispersing the titanium source in an aqueous solution containing an alkaline substance for hydrolysis to produce a hydrated titanic acid precipitate.
According to some specific embodiments, the alkaline substance is selected from one or more of aqueous ammonia, sodium hydroxide, potassium hydroxide, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, ethylenediamine, diethylamine, triethylamine, ethylamine, ethanolamine, and diethanolamine.
According to some specific embodiments, the hydrolysis reaction is carried out at normal temperature under normal pressure.
According to some specific embodiments, the step (a2) further comprises a step of purifying the obtained hydrated titanic acid precipitate crude product after hydrolysis and using the purified hydrated titanic acid precipitate in the step (b2); wherein the purification is selected from one or more of water washing—separation by centrifugation, water washing—membrane separation, water washing—filtration and dialysis.
According to some specific embodiments, the purified hydrated titanic acid has a purity of 97% or more.
According to some specific embodiments, in the step (b2), the concentration of lithium hydroxide in the aqueous hydrogen hydroxide solution containing lithium hydroxide is 0.4 mol/L to 2.0 mol/L.
According to some specific embodiments, in the step (b2), the concentration of lithium hydroxide in the aqueous hydrogen hydroxide solution containing lithium hydroxide is 1.0 mol/L to 1.5 mol/L.
According to some specific embodiments, the volume fraction of hydrogen peroxide in the aqueous hydrogen hydroxide solution containing lithium hydroxide is 0.5% to 10%.
According to some specific embodiments, the volume fraction of hydrogen peroxide in the aqueous hydrogen hydroxide solution containing lithium hydroxide is 1% to 3%.
According to some specific embodiments, the method further comprises a step of loading the surface of the obtained linear hierarchical structure lithium titanate material with one or more of carbon, carbon nanotubes, graphene, black phosphorus, metals and semiconductors, when the linear hierarchical structure lithium titanate material is obtained after the annealing treatment in the step (3).
In another aspect, the disclosure further provides a method for preparing the linear hierarchical structure lithium titanate material, wherein the method comprises the steps of:
(1) preparing a linear structure lithium peroxotitanate;
(2) subjecting the linear structure lithium peroxotitanate obtained in the step (1) to a hydrothermal reaction or a solvothermal reaction to obtain a linear hierarchical structure lithium titanate precursor;
(3) subjecting the linear hierarchical structure lithium titanate precursor obtained in the step (2) to an annealing treatment to obtain the linear hierarchical structure lithium titanate material.
In yet another aspect, the disclosure further provides an electrode material for ion battery, wherein the electrode material is mainly composed of any of the linear hierarchical structure lithium titanate material according to the disclosure.
According to some specific embodiments, the ion battery is selected from lithium ion battery, sodium ion battery, potassium ion battery, or magnesium ion battery.
It should be emphasized that the term “comprise/comprising” when used herein, refers to the presence of features, integers, steps or components, but does not preclude the presence or addition of one or more of other features, integers, steps or components.
Features described and/or illustrated with respect to one embodiment may be used in one or more of other embodiments in the same or similar manner, in combination with, or in place of, the features in other embodiments.
Any numerical value recited herein includes all values of the lower and upper values in increments of one unit from the lower limit to the upper limit, provided that there is an interval of at least two units between any lower value and any higher value. For example, if the value of the number of components or a process variable (e.g., temperature, pressure, time, etc.) is stated to be from 1 to 90, preferably from 20 to 80, more preferably from 30 to 70, it is intended that the values such as 15 to 85, 22 to 68, 43 to 51, and 30 to 32 are also explicitly listed in the specification. For a value less than 1, it is appropriately considered that one unit is 0.0001, 0.001, 0.01, or 0.1. These are merely examples that are intended to be expressly stated, and all possible combinations of numerical values recited between the minimum and maximum values are considered to be explicitly described in this specification in a similar manner.
In summary, the disclosure provides a linear hierarchical structure lithium titanate material, and preparation and application thereof. The lithium titanate material has the following advantages:
(1) For the first time, the disclosure provides a linear hierarchical structure lithium titanate material, in which the surface components are nanosheets.
(2) The long axis of the linear structure facilitates the effective migration of electrons, the sheet-like hierarchical structure facilitates the rapid intercalation and deintercalation process of lithium ions, sodium ions or potassium ions, and a large specific surface area facilitates the contact area between the electrolyte solution and the electrodes and reduces the current density, thus is excellent in a rapid charge-discharge performance of the battery.
(3) The preparation technique for the linear hierarchical structure lithium titanate material provided by the method cannot be achieved by other methods.
(4) The hierarchical structure provided by the method can increase the specific surface area of the lithium titanate, increase the contact area with the electrolyte solution when the lithium titanate is used as the electrode material, decrease the current density, and improve the battery performance.
(5) The linear hierarchical structure provided by the method can reduce the grain boundary between the particles, facilitate the transport of carriers in the long-axis direction, and enhance the application effect of the electrode material.
(6) The method has a simple preparation process, is easy to control the process parameters, uses widely available raw materials, has a low production cost, and is easy to apply to a large-scale industrial production.
Hereinafter, the implementation of the disclosure and the beneficial effects thereof are described in detail by way of specific examples, which are intended to provide a better understanding of the essence and characteristics of the disclosure, but do not limit the implementable scope of the disclosure.
Firstly, 2 g of titanium isopropoxide was dispersed in 100 ml of water, and then 5 ml of 30% hydrogen peroxide was added thereto under stirring to form a suspension containing titanium peroxo-complex. Next, 3.5 g of lithium hydroxide was added to the above peroxo-complex suspension under stirring to form a pale-yellow transparent solution. Subsequently, the pale-yellow transparent solution was heated to 80° C. and stirred at a constant temperature for 6 hours to obtain a linear structure lithium peroxotitanate as a white product. The reaction was stopped, and separation and drying were carried out to obtain the white solid. Subsequently, the above white solid was dispersed in 100 ml of water and subjected to a hydrothermal reaction at 120° C. for 6 hours to obtain a linear hierarchical structure lithium titanate precursor. Finally, the linear hierarchical structure lithium titanate precursor obtained above was heated at 450° C. for 4 hours, to obtain a linear hierarchical structure lithium titanate material.
The XRD crystal phase pattern of the linear hierarchical structure lithium titanate material obtained in this example is shown in
The low resolution SEM image of the linear hierarchical structure lithium titanate material obtained in this example is shown in
The high resolution SEM image of the linear hierarchical structure lithium titanate material obtained in this example is shown in
The SEM image of the surface nanosheet components of the linear hierarchical structure lithium titanate material obtained in this example is shown in
The results of a discharge capacity test of a lithium ion battery having the linear hierarchical structure lithium titanate material obtained in this example as an electrode material at different charge and discharge rates are shown in
Firstly, 2 g of tetrabutyl titanate was dispersed in 100 ml of water, and then 5 ml of 30% hydrogen peroxide was added thereto under stirring to form a suspension containing titanium peroxo-complex. Next, 3.5 g of lithium hydroxide was added to the above peroxo-complex suspension under stirring to form a pale-yellow transparent solution. Subsequently, the pale-yellow transparent solution was heated to 80° C. and stirred at a constant temperature for 6 hours to obtain a linear structure lithium peroxotitanate as a white product. The reaction was stopped, and separation and drying were carried out to obtain the white solid. Subsequently, the above dried white solid was placed in an oven at 150° C. and treated for 4 hours, to obtain a linear structure lithium peroxotitanate having peroxy removed on the surface thereof. Subsequently, the above white solid was dispersed in 100 ml of water and subjected to a hydrothermal reaction at 120° C. for 6 hours to obtain a linear hierarchical structure lithium titanate precursor. Finally, the linear hierarchical structure lithium titanate precursor obtained above was heated at 450° C. for 4 hours, to obtain a linear hierarchical structure lithium titanate material.
The XRD crystal phase pattern of the linear hierarchical structure lithium titanate material obtained in this example is consistent with
The SEM image of the linear hierarchical structure lithium titanate material obtained in this example is shown in
The results of a discharge capacity test of a lithium ion battery having the linear hierarchical structure lithium titanate material obtained in this example as an electrode material at different charge and discharge rates are shown in
Firstly, 1 g of titanic acid was dispersed in 100 ml of water, and then 6 ml of 30% hydrogen peroxide was added thereto under stirring to form a suspension containing titanium peroxo-complex. Next, 4 g of lithium hydroxide was added to the above peroxo-complex suspension under stirring to form a pale-yellow transparent solution. Subsequently, the pale-yellow transparent solution was heated to 90° C. and stirred at a constant temperature for 5 hours to obtain a linear structure lithium peroxotitanate as a white product. The reaction was stopped, and separation and drying were carried out to obtain the white solid. Subsequently, the above white solid was dispersed in 100 ml of an aqueous alcohol solution having a ratio of isopropanol to water of 1:5, and subjected to a hydrothermal reaction at 100° C. for 8 hours, to obtain a linear hierarchical structure lithium titanate precursor. Finally, the linear hierarchical structure lithium titanate precursor obtained above was heated at 300° C. for 6 hours, to obtain a linear hierarchical structure lithium titanate material.
The XRD crystal phase pattern of the linear hierarchical structure lithium titanate material obtained in this example is shown in
The SEM image of the linear hierarchical structure lithium titanate material obtained in this example is shown in
A lithium ion battery prepared by using the linear hierarchical structure lithium titanate material of this example as an electrode was tested to have a capacity performance close to that of the testing results of Example 1.
Under stirring, 2 g of titanium oxysulfate was dispersed and dissolved into 100 ml of water to form a solution, then aqueous ammonia at a concentration of 0.1 mol/L was slowly added dropwise to the solution until the solution was neutral (pH is about 7), so that titanium oxysulfate was gradually and completely hydrolyzed to form a hydrated titanic acid precipitate. Subsequently, the hydrated titanic acid precipitate was ultrasonically dispersed, washed several times with deionized water, and separated by centrifugation. Thereafter, hydrogen peroxide and lithium hydroxide were dissolved in water to form an aqueous solution having a lithium hydroxide concentration of 0.8 mol/L and a hydrogen peroxide volume fraction of 3%. Subsequently, the separated hydrated titanic acid precipitate was dispersed in 100 ml of the above-prepared aqueous hydrogen hydroxide solution containing lithium hydroxide, and stirred to form a yellow transparent solution. Next, the above yellow transparent solution was heated to 70° C. and then stirred under constant temperature for 10 hours, to obtain a linear structure lithium peroxotitanate white product. The reaction was stopped, and separation and drying were carried out to obtain the white solid. Subsequently, the above white solid was dispersed in 100 ml of an aqueous alcohol solution having a ratio of ethanol to water of 5:1, and subjected to a solvothermal reaction at 120° C. for 12 hours, to obtain a linear hierarchical structure lithium titanate precursor. Finally, the linear hierarchical structure lithium titanate precursor obtained above was heated at 600° C. for 3 hours, to obtain a linear hierarchical structure lithium titanate material.
The XRD crystal phase pattern of the linear hierarchical structure lithium titanate material obtained in this example is shown in
The SEM image of the linear hierarchical structure lithium titanate material obtained in this example is shown in
A lithium ion battery prepared by using the linear hierarchical structure lithium titanate material of this example as an electrode was tested to have a capacity performance close to that of the testing results of Example 1.
Firstly, 0.3 g of titanium sulfate was dispersed in 100 ml of water, and then 2 g of urea peroxide was added thereto under stirring to form a suspension containing titanium peroxo-complex. Next, 1 g of lithium peroxide was added to the above peroxo-complex suspension under stirring to form a pale-yellow transparent solution. Subsequently, the pale-yellow transparent solution was heated to 60° C. and stirred at a constant temperature for 24 hours to obtain a linear structure lithium peroxotitanate as a white product. The reaction was stopped, and separation and drying were carried out to obtain the white solid. Subsequently, the above white solid was dispersed in 100 ml of water, and subjected to a hydrothermal reaction at 100° C. for 12 hours, to obtain a linear hierarchical structure lithium titanate precursor. Finally, the linear hierarchical structure lithium titanate precursor obtained above was heated at 350° C. for 6 hours, to obtain a linear hierarchical structure lithium titanate material. The SEM image of the obtained linear hierarchical structure lithium titanate material is close to that of the product of Example 1.
A lithium ion battery prepared by using the linear hierarchical structure lithium titanate material of this example as an electrode was tested to have a capacity performance close to that of the testing results of Example 1.
Firstly, 8 g of titanic acid was dispersed in 100 ml of water, and then 25 ml of 30% hydrogen peroxide was added thereto under stirring to form a suspension containing titanium peroxo-complex. Next, 3 g of lithium oxide was added to the above peroxo-complex suspension under stirring to form a pale-yellow transparent solution. Subsequently, the pale-yellow transparent solution was heated to 100° C. and stirred at a constant temperature for 1 hour to obtain a linear structure lithium peroxotitanate as a white product. The reaction was stopped, and separation and drying were carried out to obtain the white solid. Subsequently, the above white solid was dispersed in 100 ml of water, and subjected to a hydrothermal reaction at 150° C. for 2 hours, to obtain a linear hierarchical structure lithium titanate precursor. Finally, the linear hierarchical structure lithium titanate precursor obtained above was heated at 700° C. for 1 hour, to obtain a linear hierarchical structure lithium titanate material. The SEM image of the obtained linear hierarchical structure lithium titanate material is close to that of the product of Example 1.
A lithium ion battery prepared by using the linear hierarchical structure lithium titanate material of this example as an electrode was tested to have a capacity performance close to that of the testing results of Example 1.
Firstly, 3 g of hydrated titanium oxysulfate was dispersed in 100 ml of water, and then 5 ml of 30% peracetic acid was added thereto under stirring to form a suspension containing titanium peroxo-complex. Next, 3 g of lithium superoxide was added to the above peroxo-complex suspension under stirring to form a pale-yellow transparent solution. Subsequently, the pale-yellow transparent solution was heated to 90° C. and stirred at a constant temperature for 3 hours to obtain a linear structure lithium peroxotitanate as a white product. The reaction was stopped, and separation and drying were carried out to obtain the white solid. Subsequently, the above white solid was dispersed in 100 ml of water having lithium hydroxide at a concentration of 0.1 mol/L, and subjected to a hydrothermal reaction at 140° C. for 3 hours, to obtain a linear hierarchical structure lithium titanate precursor. Finally, the linear hierarchical structure lithium titanate precursor obtained above was heated at 650° C. for 3 hours, to obtain a linear hierarchical structure lithium titanate material. The SEM image of the obtained linear hierarchical structure lithium titanate material is close to that of the product of Example 1.
A lithium ion battery prepared by using the linear hierarchical structure lithium titanate material of this example as an electrode was tested to have a capacity performance close to that of the testing results of Example 1.
Firstly, 3 g of tetrabutyl titanate was dispersed in 100 ml of water, and then 6 ml of 30% hydrogen peroxide was added thereto under stirring to form a suspension containing titanium peroxo-complex. Next, 3 g of lithium hydroxide was added to the above peroxo-complex suspension under stirring to form a pale-yellow transparent solution. Subsequently, the pale-yellow transparent solution was heated to 70° C. and stirred at a constant temperature for 12 hours to obtain a linear structure lithium peroxotitanate as a white product. The reaction was stopped, and separation and drying were carried out to obtain the white solid. Subsequently, the above white solid was dispersed in 100 ml of water having nitric acid at a concentration of 0.1 mol/L, and subjected to a hydrothermal reaction at 110° C. for 8 hours, to obtain a linear hierarchical structure lithium titanate precursor. Finally, the linear hierarchical structure lithium titanate precursor obtained above was heated at 600° C. for 4 hours, to obtain a linear hierarchical structure lithium titanate material. The SEM image is close to that of the product of Example 1.
A lithium ion battery prepared by using the linear hierarchical structure lithium titanate material of this example as an electrode was tested to have a capacity performance close to that of the testing results of Example 1.
Firstly, 3 g of tetrabutyl titanate is dispersed in 100 ml of an aqueous hydroxypropyl methyl cellulose solution at a concentration of 0.1%, and then 6 ml of 30% hydrogen peroxide was added thereto under stirring to form a suspension containing titanium peroxo-complex. Next, 3 g of lithium hydroxide was added to the above peroxo-complex suspension under stirring to form a pale-yellow transparent solution. Subsequently, the pale-yellow transparent solution was heated to 75° C. and stirred at a constant temperature for 10 hours to obtain a linear structure lithium peroxotitanate as a white product. The reaction was stopped, and separation and drying were carried out to obtain the white solid. Subsequently, the above white solid was dispersed in 100 ml of an aqueous alcohol solution having a ratio of methanol to water of 1:1, and subjected to a solvothermal reaction at 80° C. for 24 hours, to obtain a linear hierarchical structure lithium titanate precursor. Finally, the linear hierarchical structure lithium titanate precursor obtained above was heated at 350° C. for 8 hours, to obtain a linear hierarchical structure lithium titanate material. The SEM image of the obtained linear hierarchical structure lithium titanate material is close to that of the product of Example 1.
A lithium ion battery prepared by using the linear hierarchical structure lithium titanate material of this example as an electrode was tested to have a capacity performance close to that of the testing results of Example 1.
Firstly, 2 g of titanium isopropoxide is dispersed in 100 ml of an aqueous polyvinyl alcohol solution at a concentration of 0.5%, and then 5 ml of 30% hydrogen peroxide was added thereto under stirring to form a suspension containing titanium peroxo-complex. Next, 3.5 g of lithium hydroxide was added to the above peroxo-complex suspension under stirring to form a pale-yellow transparent solution. Subsequently, the pale-yellow transparent solution was heated to 85° C. and stirred at a constant temperature for 6 hours to obtain a linear structure lithium peroxotitanate as a white product. The reaction was stopped, and separation and drying were carried out to obtain the white solid. Subsequently, the above white solid was dispersed in 100 ml of water, and subjected to a hydrothermal reaction at 120° C. for 6 hours, to obtain a linear hierarchical structure lithium titanate precursor. Finally, the linear hierarchical structure lithium titanate precursor obtained above was immersed in 50 ml of a glucose solution having a concentration of 1 mol/L, centrifuged and dried, and then heated in an inert atmosphere at 550° C. for 4 hours to obtain a carbon-supported linear hierarchical structure lithium titanate material. The SEM image of the obtained linear hierarchical structure lithium titanate material is close to that of the product of Example 1.
A lithium ion battery prepared by using the linear hierarchical structure lithium titanate material of this example as an electrode was tested to have a capacity performance close to that of the testing results of Example 1.
Firstly, 1.5 g of titanium isopropoxide was dispersed in 100 ml of water, and then 4 ml of 30% hydrogen peroxide was added thereto under stirring to form a suspension containing titanium peroxo-complex. Next, 3 g of lithium hydroxide was added to the above peroxo-complex suspension under stirring to form a pale-yellow transparent solution. Subsequently, the pale-yellow transparent solution was heated to 75° C. and stirred at a constant temperature for 8 hours to obtain a linear structure lithium peroxotitanate as a white product. The reaction was stopped, and separation and drying were carried out to obtain the white solid. Subsequently, the above dried white solid was placed in an oven at 150° C. and treated for 4 hours, to obtain a linear structure lithium peroxotitanate having peroxy removed on the surface thereof. Subsequently, the above white solid was dispersed in 100 ml of water and subjected to a hydrothermal reaction at 120° C. for 6 hours to obtain a linear hierarchical structure lithium titanate precursor. Finally, the linear hierarchical structure lithium titanate precursor obtained above was heated at 450° C. for 4 hours, to obtain a linear hierarchical structure lithium titanate material. The SEM image of the obtained linear hierarchical structure lithium titanate material is close to that of the product of Example 1.
A lithium ion battery prepared by using the linear hierarchical structure lithium titanate material of this example as an electrode was tested to have a capacity performance close to that of the testing results of Example 1.
Firstly, 0.5 g of titanium sulfate was dispersed in 100 ml of water, and then 2.5 g of urea peroxide was added thereto under stirring to form a suspension containing titanium peroxo-complex. Next, 1.2 g of lithium peroxide was added to the above peroxo-complex suspension under stirring to form a pale-yellow transparent solution. Subsequently, the pale-yellow transparent solution was heated to 65° C. and stirred at a constant temperature for 20 hours to obtain a linear structure lithium peroxotitanate as a white product. The reaction was stopped, and separation and drying were carried out to obtain the white solid. Subsequently, the above dried white solid was placed in an oven at 200° C. and treated for 1 hour, to obtain a linear structure lithium peroxotitanate having peroxy removed on the surface thereof. Subsequently, the above white solid was dispersed in 100 ml of water, and subjected to a hydrothermal reaction at 150° C. for 2 hours, to obtain a linear hierarchical structure lithium titanate precursor. Finally, the linear hierarchical structure lithium titanate precursor obtained above was heated at 550° C. for 3 hours, to obtain a linear hierarchical structure lithium titanate material. The SEM image of the obtained linear hierarchical structure lithium titanate material is close to that of the product of Example 1.
A lithium ion battery prepared by using the linear hierarchical structure lithium titanate material of this example as an electrode was tested to have a capacity performance close to that of the testing results of Example 1.
Firstly, 8 g of titanic acid was dispersed in 100 ml of water, and then 25 ml of 30% hydrogen peroxide was added thereto under stirring to form a suspension containing titanium peroxo-complex. Next, 3 g of lithium oxide was added to the above peroxo-complex suspension under stirring to form a pale-yellow transparent solution. Subsequently, the pale-yellow transparent solution was heated to 100° C. and stirred at a constant temperature for 2 hours to obtain a linear structure lithium peroxotitanate as a white product. The reaction was stopped, and separation and drying were carried out to obtain the white solid. Subsequently, the above dried white solid was placed in an oven at 120° C. and treated for 10 hours, to obtain a linear structure lithium peroxotitanate having peroxy removed on the surface thereof. Subsequently, the above white solid was dispersed in 100 ml of water, and subjected to a hydrothermal reaction at 100° C. for 12 hours, to obtain a linear hierarchical structure lithium titanate precursor. Finally, the linear hierarchical structure lithium titanate precursor obtained above was heated at 350° C. for 8 hours, to obtain a linear hierarchical structure lithium titanate material. The SEM image of the obtained linear hierarchical structure lithium titanate material is close to that of the product of Example 1.
A lithium ion battery prepared by using the linear hierarchical structure lithium titanate material of this example as an electrode was tested to have a capacity performance close to that of the testing results of Example 1.
Firstly, 2.5 g of titanium isopropoxide was dispersed in 100 ml of an aqueous polyvinyl alcohol solution at a concentration of 0.8%, and then 6 ml of 30% hydrogen peroxide was added thereto under stirring to form a suspension containing titanium peroxo-complex. Next, 4 g of lithium hydroxide was added to the above peroxo-complex suspension under stirring to form a pale-yellow transparent solution. Subsequently, the pale-yellow transparent solution was heated to 80° C. and stirred at a constant temperature for 8 hours to obtain a linear structure lithium peroxotitanate as a white product. The reaction was stopped, and separation and drying were carried out to obtain the white solid. Subsequently, the above dried white solid was placed in an oven at 180° C. and treated for 2 hours, to obtain a linear structure lithium peroxotitanate having peroxy removed on the surface thereof. Subsequently, the above white solid was dispersed in 100 ml of an aqueous alcohol solution having a ratio of ethanol to water of 1:1, and subjected to a solvothermal reaction at 150° C. for 1 hour, to obtain a linear hierarchical structure lithium titanate precursor. Next, the linear hierarchical structure lithium titanate precursor obtained above was heated at 650° C. for 3 hours to obtain a linear hierarchical structure lithium titanate material. Finally, the linear hierarchical structure lithium titanate precursor obtained above was immersed in 50 ml of an aqueous graphene oxide solution having a concentration of 0.1%, and dried, and then subjected to an annealing treatment in an inert atmosphere at 500° C. for 5 hours to obtain a graphene-supported linear hierarchical structure lithium titanate material. The SEM image of the obtained linear hierarchical structure lithium titanate material is close to that of the product of Example 1.
A lithium ion battery prepared by using the linear hierarchical structure lithium titanate material of this example as an electrode was tested to have a capacity performance close to that of the testing results of Example 1.
Under stirring, 0.5 g of titanium tetrachloride was dispersed and dissolved into 100 ml of water to form a solution, then an aqueous sodium hydroxide solution at a concentration of 0.01 mol/L was slowly added dropwise to the solution until the solution was neutral (pH is about 7), so that titanium tetrachloride was gradually and completely hydrolyzed to form a hydrated titanic acid precipitate. Subsequently, the hydrated titanic acid precipitate was ultrasonically dispersed, washed several times with deionized water, and separated by centrifugation. Thereafter, hydrogen peroxide and lithium hydroxide were dissolved in water to form an aqueous solution having a lithium hydroxide concentration of 0.4 mol/L and a hydrogen peroxide volume fraction of 1%. Subsequently, the separated hydrated titanic acid precipitate was dispersed in 100 ml of the above-prepared aqueous hydrogen hydroxide solution containing lithium hydroxide under stirring to form a yellow transparent solution. Next, the above yellow transparent solution was heated to 60° C. and then stirred at constant temperature for 24 hours. The reaction was stopped, and separation and drying were carried out to obtain the white solid. Subsequently, the above white solid was dispersed in 100 ml of water, and subjected to a hydrothermal reaction at 130° C. for 5 hours, to obtain a linear hierarchical structure lithium titanate precursor. Finally, the linear hierarchical structure lithium titanate precursor obtained above was heated at 400° C. for 5 hours, to obtain a linear hierarchical structure lithium titanate material. The SEM image of the obtained linear hierarchical structure lithium titanate material is close to that of the product of Example 1.
A lithium ion battery prepared by using the linear hierarchical structure lithium titanate material of this example as an electrode was tested to have a capacity performance close to that of the testing results of Example 1.
Under stirring, 5 g of titanium sulfate was dispersed and dissolved into 100 ml of water to form a solution, then an aqueous potassium hydroxide solution at a concentration of 0.5 mol/L was slowly added dropwise to the solution until the solution was neutral (pH is about 7), so that titanium sulfate was gradually and completely hydrolyzed to form a hydrated titanic acid precipitate. Subsequently, the hydrated titanic acid precipitate was ultrasonically dispersed, washed several times with deionized water, and separated by centrifugation. Thereafter, hydrogen peroxide and lithium hydroxide were dissolved in water to form an aqueous solution having a lithium hydroxide concentration of 1.0 mol/L and a hydrogen peroxide volume fraction of 8%. Subsequently, the separated hydrated titanic acid precipitate was dispersed in 100 ml of the above-prepared aqueous hydrogen hydroxide solution containing lithium hydroxide under stirring to form a yellow transparent solution. Next, the above yellow transparent solution was heated to 100° C. and then stirred at constant temperature for 1 hour. The reaction was stopped, and separation and drying were carried out to obtain the white solid. Subsequently, the above white solid was dispersed in 100 ml of water, and subjected to a hydrothermal reaction at 140° C. for 4 hours, to obtain a linear hierarchical structure lithium titanate precursor. Finally, the linear hierarchical structure lithium titanate precursor obtained above was heated at 600° C. for 3 hours, to obtain a linear hierarchical structure lithium titanate material. The SEM image of the obtained linear hierarchical structure lithium titanate material is close to that of the product of Example 1.
A lithium ion battery prepared by using the linear hierarchical structure lithium titanate material of this example as an electrode was tested to have a capacity performance close to that of the testing results of Example 1.
Under stirring, 1 g of titanium isopropoxide was dispersed in 100 ml of an aqueous solution for direct hydrolysis to form a hydrated titanic acid precipitate. Subsequently, the hydrated titanic acid precipitate was ultrasonically dispersed, washed several times with deionized water, and separated by centrifugation. Thereafter, hydrogen peroxide and lithium hydroxide were dissolved in water to form an aqueous solution having a lithium hydroxide concentration of 0.6 mol/L and a hydrogen peroxide volume fraction of 2%. Subsequently, the separated hydrated titanic acid precipitate was dispersed in 100 ml of the above-prepared aqueous hydrogen hydroxide solution containing lithium hydroxide under stirring to form a yellow transparent solution. Next, the above yellow transparent solution was heated to 85° C. and then stirred at constant temperature for 5 hours. The reaction was stopped, and separation and drying were carried out to obtain the white solid. Subsequently, the above dried white solid was placed in an oven at 160° C. and treated for 3 hours, to obtain a linear structure lithium peroxotitanate having peroxy removed on the surface thereof. Subsequently, the above white solid was dispersed in 100 ml of water and subjected to a hydrothermal reaction at 130° C. for 5 hours to obtain a linear hierarchical structure lithium titanate precursor. Finally, the linear hierarchical structure lithium titanate precursor obtained above was heated at 350° C. for 8 hours, to obtain a linear hierarchical structure lithium titanate material. The SEM image of the obtained linear hierarchical structure lithium titanate material is close to that of the product of Example 1.
A lithium ion battery prepared by using the linear hierarchical structure lithium titanate material of this example as an electrode was tested to have a capacity performance close to that of the testing results of Example 1.
Under stirring, 3 g of tetrabutyl titanate was dispersed in 100 ml of an aqueous solution for direct hydrolysis to form a hydrated titanic acid precipitate. Subsequently, the hydrated titanic acid precipitate was ultrasonically dispersed, washed several times with deionized water, and separated by centrifugation. Thereafter, hydrogen peroxide and lithium hydroxide were dissolved in water to form an aqueous solution having a lithium hydroxide concentration of 0.7 mol/L and a hydrogen peroxide volume fraction of 4%. Subsequently, the separated hydrated titanic acid precipitate was dispersed in 100 ml of the above-prepared aqueous hydrogen hydroxide solution containing lithium hydroxide under stirring to form a yellow transparent solution. Next, the above yellow transparent solution was heated to 70° C. and then stirred at constant temperature for 6 hours. The reaction was stopped, and separation and drying were carried out to obtain the white solid. Subsequently, the above dried white solid was placed in an oven at 130° C. and treated for 10 hours, to obtain a linear structure lithium peroxotitanate having peroxy removed on the surface thereof. Subsequently, the above white solid was dispersed in 100 ml of an aqueous alcohol solution having a ratio of ethanol to water of 1:1 and subjected to a solvothermal reaction at 100° C. for 8 hours to obtain a linear hierarchical structure lithium titanate precursor. Finally, the linear hierarchical structure lithium titanate precursor obtained above was heated at 550° C. for 4 hours, to obtain a linear hierarchical structure lithium titanate material. The SEM image of the obtained linear hierarchical structure lithium titanate material is close to that of the product of Example 1.
A lithium ion battery prepared by using the linear hierarchical structure lithium titanate material of this example as an electrode was tested to have a capacity performance close to that of the testing results of Example 1.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201811038606.9 | Sep 2018 | CN | national |
