CN108975388B

CN108975388B - One-pot synthesis LiEuTiO4Method for preparing anode material of lithium ion battery

Info

Publication number: CN108975388B
Application number: CN201810800335.XA
Authority: CN
Inventors: 童东革; 魏大; 唐奇娟
Original assignee: Chengdu Univeristy of Technology
Current assignee: Chengdu Univeristy of Technology
Priority date: 2018-07-20
Filing date: 2018-07-20
Publication date: 2020-05-26
Anticipated expiration: 2038-07-20
Also published as: CN108975388A

Abstract

The invention discloses a one-pot method for synthesizing LiEuTiO₄A method for preparing anode material of lithium ion battery. LiEuTiO synthesized by the method₄The lithium ion battery anode material is prepared by the method which adopts the previously reported step-by-step synthesis method₄The anode material has better electrochemical performance. The technology of the invention greatly optimizes the step-by-step synthesis technology reported previously, so that the synthesis time and labor cost of the material are reduced to a great extent, and the material is more beneficial in future industrialization and commercialization processes, and has better application prospect.

Description

One-pot synthesis LiEuTiO4Method for preparing anode material of lithium ion battery

Technical Field

The invention relates to the technical field of anode materials of lithium ion batteries, in particular to a one-pot synthesis LiEuTiO₄A method for preparing anode material of lithium ion battery.

Background

With the decreasing reserves of coal, oil and natural gas as well as the growing concern of a series of environmental problems caused by the above, people are aware that in order to maintain the sustainable development of human beings, energy and environment are two serious problems which must be faced in the 21 st century, and the development of clean and renewable new energy sources, such as electrochemical energy storage and hydrogen energy, will become one of the most decisive technical fields in the world economy. Therefore, energy storage materials have become the focus of current research.

In electrochemical energy storage, the lithium ion battery has the advantages of high voltage, high capacity and high energy, long cycle life and good safety performance, so that the lithium ion battery has wide application prospects in various aspects such as portable electronic equipment, electric automobiles, space technology, national defense industry and the like, becomes a research hotspot which is widely concerned in recent years, and is considered to be an energy storage device with the most development prospect.

The graphite serving as the cathode material of the lithium ion battery on the market at present easily causes the problem of lithium dendrite in a cathode region due to the low intercalation potential (about 0.1V), thereby causing a safety problem. Recent studies have found that Li₄Ti₅O₁₂The negative electrode material has a high intercalation potential, so that the lithium dendrite problem is not easily caused, but the high intercalation potential causes the energy density of the battery to be reduced, thereby influencing the energy density of the battery.

Recently, the anode material LiEuTiO of the lithium ion battery is discovered₄The intercalation potential of (a) is low, about 0.8V, which is sufficient to avoid cell safety problems caused by the formation of lithium dendrites, while also ensuring an increased energy density of the lithium battery. Go toTube LiEuTiO₄The performance of the material is quite good, but the methods for preparing the material reported at present are complex, and the material is generally prepared by lithium ions and NaEuTiO₄The sodium ion exchange is obtained by multi-step synthesis, the preparation steps are redundant, and the preparation cost is very high. This makes industrial application of the material costly and thus difficult to commercialize. The material is synthesized by adopting a one-pot method, so that the manufacturing cost is reduced, and the commercialization of the material is more favorable.

Disclosure of Invention

The invention adopts liquid phase plasma technology (SPT), uses a liquid phase plasma reactor with proprietary intellectual property rights (utility model: 201420301030.1), and synthesizes LiEuTiO by a one-pot method₄. In the following description of the present patent, LiEuTiO synthesized by a one-pot method₄For short: OSR-LiEuTiO₄LiEuTiO prepared in multiple steps according to previously reported methods₄For short: MSR-LiEuTiO₄. OSR-LiEuTiO prepared by the invention₄Shows better electrochemical performance. When the voltage is in the range of 0.01-3V, 0.1Ag is added^-1When circulating, the first discharge capacity is 237.3mAhg^-1And has a good capacity retention rate of 97.0% after 100 cycles. In addition, it is in 5 Ag^-1It has a height of 156.2 mAhg^-1High specific capacity of (2).

The invention adopts the following technical scheme:

(1) mixing LiCl and EuCl₃Mixed with bis (2-hydroxypropionic acid) diammonium titanium dihydroxide (TALH) and dissolved in 1-butyl-3-methylimidazole ([ BMIM)]Cl) into a liquid phase plasma reactor;

(2) mixing O with₂Introducing into the solution;

(3) the liquid phase plasma reaction was carried out for 30 minutes while vigorously stirring. The electric field between the two electrodes of the liquid phase plasma reactor is 750Vcm^-1;

(4) Repeatedly washing the obtained product with deionized water;

(5) it was dried at 80 ℃.

The amount of [ BMIM ] Cl liquid in the step (1) is 20mL;

the amount of LiCl in the step (1) is 2 mmol;

EuCl in step (1)₃The amount of (B) is 1 mmol;

the amount of TALH in the step (1) is 1 mmol;

in step (2), O₂Flow rate of 5mLmin^-1;

In the step (3), the electric field between the two electrodes of the liquid phase plasma reactor is 750Vcm^-1;

The reaction time in step (3) is 30 min.

The invention has the following positive effects:

1) the invention adopts a one-pot method to synthesize OSR-LiEuTiO₄Lithium battery anode material, and the presently reported preparation of LiEuTiO₄Compared with the method for preparing the anode material, the method has simple operation steps and short time consumption, thereby being more beneficial to industrialization.

2) LiEuTiO prepared by the invention₄The performance of the lithium battery anode material is superior to that of MSR-LiEuTiO prepared according to the previous report method in multiple steps₄And the currently reported LiEuTiO₄Anode material (chem. Commun. 2017;53: 7800-3).

Drawings

FIG. 1 is the one-pot synthesis of OSR-LiEuTiO of example 1₄And (5) XRD diffraction refining results of the lithium ion battery anode material.

FIG. 2 is the one-pot synthesis of OSR-LiEuTiO of example 1₄ A Ti 2p XPS spectrum (a) and a Eu 3d XPS spectrum (b) of the anode material of the lithium ion battery.

FIG. 3 is the one-pot synthesis of OSR-LiEuTiO of example 1₄SEM photographs of the lithium ion battery anode material.

FIG. 4 is a multi-step preparation of MSR-LiEuTiO according to a previously reported method₄SEM photographs of the lithium ion battery anode material.

FIG. 5 is the one-pot synthesis of OSR-LiEuTiO of example 1₄Lithium ion battery anode material and MSR-LiEuTiO prepared in multiple steps according to previously reported methods₄At a scan rate of 1mVs^-1Cyclic voltammograms of time; .

FIG. 6 is the one-pot synthesis of OSR-LiEuTiO of example 1₄Lithium ion battery anode material and MSR-LiEuTiO prepared in multiple steps according to previously reported methods₄At a magnification of 0.1Ag^-1First discharge profile of time.

FIG. 7 is the one-pot synthesis of OSR-LiEuTiO of example 1₄Lithium ion battery anode material and MSR-LiEuTiO prepared in multiple steps according to previously reported methods₄At a magnification of 0.1Ag^-1Cyclic performance graph of time.

FIG. 8 is the one-pot synthesis of OSR-LiEuTiO of example 1₄Lithium ion battery anode material and MSR-LiEuTiO prepared in multiple steps according to previously reported methods₄Cycle performance plot at different magnifications

FIG. 9 is the one-pot synthesis of OSR-LiEuTiO of example 1₄Lithium ion battery anode material and literature reported LiEuTiO₄Graph comparing the performance of the material (chem. Commun. 2017;53: 7800-3) at different magnifications.

Detailed Description

The following examples are further detailed descriptions of the present invention.

The experimental procedures used in the following examples are all conventional procedures unless otherwise specified.

Materials, reagents and the like used in the following examples are commercially available unless otherwise specified.

Example 1

To achieve the above object, LiEuTiO synthesized in one pot₄The preparation method of the anode material of the lithium ion battery comprises the following steps:

1) 2mmol of LiCl, 1mmol of EuCl₃And 1mmol of bis (2-hydroxypropionic acid) diammonium dihydroxide Titanium (TALH) were mixed and dissolved in 20mL of 1-butyl-3-methylimidazole chloride ([ BMIM)]Cl) into a liquid phase plasma reactor;

2) mixing O with₂And introducing into the solution. O is₂Flow rate of 5mLmin^-1;

3) The liquid phase plasma reaction was carried out for 30 minutes while vigorously stirring. Between two electrodes of a liquid-phase plasma reactorElectric field of 750Vcm^-1;

4) Repeatedly washing the obtained product with deionized water;

5) it was dried at 80 ℃.

EXAMPLE 1 preparation of OSR-LiEuTiO₄The experimental and calculated XRD patterns of (a) are shown in fig. 1. The lattice parameters of a, b and c are 1.13971,0.53593 and 0.53580 nm, respectively. It is consistent with literature reports. The Ti 2p and Eu 3dXPS spectra of the samples are shown in FIGS. 2a and b. XPS peaks highlighted at 1165.0 and 1135.0eV correspond to Eu, respectively³⁺3d_3/2And Eu ³⁺3d_5/2（3d⁴f⁶) Indicating OSR-LiEuTiO₄The oxidation state of medium Eu is + 3. Meanwhile, the valence of Ti is +4, wherein two peaks are 465.3 and 459.6eV, respectively, corresponding to Ti ⁴⁺2p_1/2And Ti ⁴⁺2p_3/2。

SEM image in FIG. 3 shows OSR-LiEuTiO₄Is uniform and has an average particle size of about 160nm, which is smaller than that of LiEuTiO prepared by a multi-step synthesis method reported previously₄（MSR-LiEuTiO₄) Average particle size (FIG. 4). Furthermore, it has a height of 121.3 m²g^-1Has a high specific surface area greater than that of MSR-LiEuTiO₄（16.6 m²g^-1) Specific surface area of (2). Thus, OSR-LiEuTiO₄It is expected to be used as a negative electrode material for high capacity lithium ion batteries because its high specific surface area and smaller particle size will facilitate penetration of electrolyte and shorten ion/electron diffusion distance.

In addition thereto, OSR-LiEuTiO was studied₄As an anode material of a Lithium Ion Battery (LIB), MSR-LiEuTiO was used₄A comparison is made. The cyclic voltammogram shows that OSR-LiEuTiO₄Exhibits a ratio of MSR-LiEuTiO₄More preferable Li⁺Storage performance (fig. 5). Two peaks near 0.8V and 1.0V correspond to Li, respectively⁺Peak insertion/removal. OSR-LiEuTiO₄Lower Li of⁺The extraction potential and its higher Li⁺The insertion potential indicates its Li during cycling⁺Intercalation/deintercalation reversibility ratio MSR-LiEuTiO₄And more preferably. Furthermore, OSR-LiEuTiO₄The area of the cyclic voltammetry curve is far higher than that of MSR-LiEuTiO₄Indicating that it has a higher capacity.

FIG. 6 shows two samples at 0.1Ag^-1Initial charge-discharge curve under charge-discharge rate. MSR-LiEuTiO₄Initial discharge capacity of 74.8mAhg^-1Reversible charge capacity of 55.6mAhg^-1. Its irreversible capacity loss reaches 26.7%. Furthermore, OSR-LiEuTiO₄Initial discharge capacity of 237.3mAhg^-1Which is larger than the previously reported LiEuTiO₄（219.2mAhg^-1) The maximum specific capacity (chem. Commun. 2017;53: 7800-3). Further, the initial charge capacity of the sample was 213.8mAhg^-1The initial capacity loss was only 10.1%. OSR-LiEuTiO₄Good Li⁺The storage properties can be attributed to its high specific surface area.

FIG. 7 shows that the two samples are at 0.1Ag^-1Cycling performance under charge-discharge rate. After 75 cycles, MSR-LiEuTiO₄Has a reversible capacity of only 39.2 mAhg^-1The capacity loss was 22.0%. In contrast, OSR-LiEuTiO₄Shows a low capacity fade (10.0%) even after 100 cycles and a reversible capacity of 208.7mAhg^-1。

FIG. 8 compares two samples at 0.2-5.0Ag^-1Rate performance at charge and discharge rate. OSR-LiEuTiO₄Has a reversible capacity of 0.2 Ag^-1It is 204.3 mAhg^-1At 5.0Ag^-1It is 144.9mAhg^-1. The corresponding coulomb efficiency was about 92.7%. And MSR-LiEuTiO₄At 0.2 Ag^-1The capacity in the case is only 45.9mAhg^-1At 5.0Ag^-1Lower capacity of only 7.2mAhg^-1. This significant difference between the two materials, especially at high rates, is attributed to the OSR-LiEuTiO₄Smaller particle size and higher specific surface area of Li⁺And electrons in LiEuTiO₄And the bulk phase has a faster diffusion rate. When the charge-discharge multiplying power is changed back to 0.1Ag^-1When the specific capacity is recovered to 213.8mAhg^-1. Furthermore, we prepared OSR-LiEuTiO₄The charge-discharge rate performance of the material is also superior to that of the material reported in the literatureLiEuTiO (II)₄(chem. Commun. 2017;53: 7800-3) (FIG. 9).

The invention successfully prepares LiEuTiO by adopting a one-pot method₄An anode material of a lithium ion battery. The material has better electrochemical performance compared with other reported lithium ion electrode materials. Compared with the previously reported method, the preparation method of the material has the advantages of many simplified steps and short time consumption, and is more beneficial to the industrial and commercial development of the material.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. One-pot synthesis LiEuTiO₄The method for preparing the anode material of the lithium ion battery is characterized by comprising the following steps: the synthesis method comprises the following specific steps:

(1) 2mmol of LiCl, 1mmol of EuCl₃And 1mmol of bis (2-hydroxypropionic acid) diammonium dihydroxide Titanium (TALH) were mixed and dissolved in 20mL of 1-butyl-3-methylimidazole chloride ([ BMIM)]Cl) into a liquid phase plasma reactor;

(2) mixing O with₂Into the solution, O₂Flow rate of 5mLmin^-1；

(3) Performing liquid phase plasma reaction for 30min while stirring vigorously, wherein the electric field between two electrodes of the liquid phase plasma reactor is 750Vcm^-1；

(4) Repeatedly washing the obtained product with deionized water;

(5) it was dried at 80 ℃.