CN107742716B

CN107742716B - Electrode material of lithium ion battery and preparation method thereof

Info

Publication number: CN107742716B
Application number: CN201710946829.4A
Authority: CN
Inventors: 林春富; 楼晓鸣; 符庆丰; 陈拥军
Original assignee: Hainan University
Current assignee: Hunan Chenzhi Nano Material Technology Co ltd
Priority date: 2017-10-12
Filing date: 2017-10-12
Publication date: 2020-04-07
Anticipated expiration: 2037-10-12
Also published as: CN107742716A

Abstract

The invention belongs to the technical fields of electrochemistry, material chemistry and chemical power products, and more particularly, relates to an electrode material of a lithium ion battery and a preparation method thereof. The chemical formula of the electrode material provided by the present invention is MNb ₁₁ O ₂₉ , and the M is Al, Ga or Cr. The electrode material provided by the invention has the advantages of high theoretical specific capacity, high safety performance, high reversible specific capacity, high Coulombic efficiency and excellent cycle performance as a negative electrode material of lithium ion battery. The preparation method provided by the invention has a simple synthesis process, is suitable for charging and discharging of high-power devices such as electric vehicles, and has broad application prospects in the field of lithium ion batteries. The invention provides more choices for the M-Nb-O material to be used in the negative electrode material of lithium ion batteries, has broad application prospects in the field of lithium ion batteries used in electric vehicles, and accelerates the popularization of electric vehicles.

Description

Electrode material of lithium ion battery and preparation method thereof

Technical Field

The invention belongs to the technical field of electrochemistry, material chemistry and chemical power supply products, and particularly relates to an electrode material of a secondary lithium ion battery and a preparation method thereof.

Background

Lithium ion batteries are recognized as a very promising energy source for electric vehicles due to their advantages of high energy output, high conversion efficiency, long storage life, etc. As a conventional commercial negative electrode material, graphite has a high specific capacity (372 mAh g theoretically^-1) In addition, the advantages of low cost, long cycle life and the like are also provided. However, its operating potential is so low that after the first discharge to below 1V, the electrolyte begins to decompose, forming a solid electrolyte interfacial film on the surface of the negative electrode. During high-rate charge and discharge, metallic lithium is easily precipitated on the surface of a carbon electrode to form dendritic crystals due to a solid electrolyte interface film, and the existence of the lithium dendritic crystals can cause short circuit of a battery, so that serious potential safety hazards are brought. Furthermore, graphite has a low lithium ion diffusion coefficient, resulting in poor rate performance. These problems have hindered the use of graphite in high performance lithium ion batteries. Therefore, it is necessary to develop a negative electrode material having good electrochemical properties, including high safety, reversible specific capacity, rate capability and cycling stabilityAnd (4) sex.

Of the numerous negative electrode materials, M-Ti-O compound materials have been extensively studied because of their safe working potential (Ti)³⁺/ Ti⁴⁺) Thereby suppressing reduction of the electrolyte and formation of lithium dendrites. Wherein "zero strain" Li₄Ti₅O₁₂The material is the most widely studied M-Ti-O negative electrode material. Li₄Ti₅O₁₂The modified nano-carbon nano-material can have the advantages of safety, stability and quick charge and discharge, but has the inherent low theoretical capacity (only 175 mAh g)^-1) Limiting its application.

To solve this problem, M-Nb-O negative electrode materials have been studied as alternative materials to M-Ti-O negative electrode materials. Compared with M-Ti-O material, M-Nb-O material also has safe working potential (Nb)³⁺/ Nb⁴⁺And Nb⁴⁺/ Nb⁵ ⁺). Since Nb³⁺And Nb⁵⁺Two electrons are transferred between the two, and the M-Nb-O material has higher theoretical capacity. Furthermore, M-Nb-O materials compare to Li₄Ti₅O₁₂The material has a more open space structure, and is more beneficial to the conduction of lithium ions, so that the M-Nb-O material has better electrochemical performance. However, the M-Nb-O negative electrode materials developed so far are very limited, mainly Ti-Nb-O negative electrode materials. Therefore, it is necessary to search more M-Nb-O negative electrode materials with good electrochemical properties for lithium ion batteries.

Disclosure of Invention

Aiming at the situation that few M-Nb-O materials are used for lithium ion batteries in the prior art, the invention aims to provide a novel electrode material of a secondary lithium ion battery, and aims to solve the problem that an electric automobile cannot be popularized due to the fact that only a few M-Nb-O materials can be selected as lithium ion battery cathode materials.

The invention also provides a preparation method of the electrode material of the secondary lithium ion battery.

The technical scheme adopted by the invention for realizing the purpose is as follows:

the invention provides a lithium ion batteryAn electrode material for a cell, said electrode material having the chemical formula MNb₁₁O₂₉And M is Al, Ga or Cr.

The invention also provides a preparation method of the electrode material, which comprises a solid-phase reaction method or an electrostatic spinning method;

the solid phase reaction method comprises the following steps:

mixing an aluminum source, a gallium source or a chromium source and a niobium source by high-energy ball milling and then sintering to obtain an electrode material MNb₁₁O₂₉Powder;

the molar ratio of the aluminum source, the gallium source or the chromium source to the niobium source is 1: 11;

the electrostatic spinning method comprises the following steps:

(1) dissolving 0.001 mol of aluminum source, gallium source or chromium source, 2 mL of hydrolysis-resistant agent and 1 g of adhesive in 10 mL of organic solvent to form aluminum solution, gallium solution or chromium solution;

(2) dissolving 0.011 mol of niobium source in 5 mL of organic solvent to form niobium solution;

(3) uniformly mixing an aluminum solution, a gallium solution or a chromium solution and a niobium solution, then obtaining fibers through electrostatic spinning, and drying the fibers;

(4) sintering the dried fiber to obtain an electrode material MNb₁₁O₂₉And (3) powder.

Further, the aluminum source is aluminum oxide or aluminum salt; the gallium source is gallium sesquioxide or gallium salt; the chromium source is chromium oxide or chromium salt;

the aluminum salt is aluminum acetylacetonate or aluminum acetate; the gallium salt is gallium acetylacetonate or gallium acetate; the chromium salt is chromium acetylacetonate or chromium acetate.

Further, the niobium source is niobium pentoxide, niobium powder, niobium oxalate or niobium ethoxide.

The electrostatic spinning conditions in the preparation process of the electrode material prepared by the invention are as follows: the diameter of the needle is 21G, the capacity of the syringe is 10 mL, the distance between the needle and the receiving plate is 15 cm, the flow rate of the solution is 0.5 mm per minute, and the voltage is 15 kV.

Further, the hydrolysis resistant agent is acetic acid or citric acid.

Further, the adhesive is polyvinylpyrrolidone or polyacrylonitrile.

Further, the organic solvent is N, N-dimethylformamide or ethanol.

In the preparation method, the drying temperature is 80 ℃; the sintering temperature is 750-1400 ℃, and the sintering time is 2-6 h.

The starting materials used in the above-mentioned production methods are all commercially available unless otherwise specified.

In the invention, the electrode materials of the secondary lithium ion battery are respectively AlNb₁₁O₂₉，GaNb₁₁O₂₉And CrNb₁₁O₂₉(ii) a Wherein AlNb₁₁O₂₉Has a theoretical specific capacity of 389 mAh g^-1，GaNb₁₁O₂₉Theoretical specific capacity of 379 mAh g^-1，CrNb₁₁O₂₉Theoretical specific capacity of 383 mAh g^-1. All three materials have relatively high working potential, so that the safety is good. In addition, the materials have good electrochemical performance, and the AlNb prepared by the solid phase method₁₁O₂₉The first coulombic efficiency of charge and discharge under 0.1C multiplying power is as high as 96.3 percent, and the reversible specific capacity is as high as 257 mAh g^-1The reversible specific capacity is still 67 mAh g under the multiplying power of 10C^-1After 200 cycles, 83.3% of the capacity remained. GaNb prepared by solid phase method₁₁O₂₉The first coulombic efficiency of charge and discharge under 0.1C multiplying power is as high as 94.4 percent, and the reversible specific capacity is as high as 255 mAh g^-1The reversible specific capacity is still 124 mAh g under the multiplying power of 10C^-1After 200 cycles, 97.5% of the capacity remained. CrNb prepared by solid phase method₁₁O₂₉The first coulombic efficiency of charge and discharge under 0.1C multiplying power is as high as 93.8 percent, and the reversible capacity ratio is as high as 278 mAh g^-1The reversible specific capacity is still 148 mAh g under the multiplying power of 10C^-1After 200 cycles, 96.1% of capacity remains. AlNb prepared by electrostatic spinning method₁₁O₂₉The first coulombic efficiency of charge and discharge under 0.1C multiplying power is as high as 90.4 percent, and the reversible specific capacity is as high as 253mAh g^-1At a magnification of 10CThe reversible specific capacity is still 123 mAh g^-1After 200 cycles, 94.3% of capacity remains. GaNb prepared by electrostatic spinning method₁₁O₂₉The first coulombic efficiency of charge and discharge under 0.1C multiplying power is as high as 96.4 percent, and the reversible specific capacity is as high as 276 mAh g^-1The reversible specific capacity is still 174 mAh g under the multiplying power of 10C^-1After 200 cycles, 98.3% of the capacity remains. CrNb prepared by electrostatic spinning method₁₁O₂₉The first coulombic efficiency of charge and discharge under 0.1C multiplying power is as high as 94.9 percent, and the reversible specific capacity is as high as 368 mAh g^-1The reversible specific capacity is still 184 mAh g under the multiplying power of 10C^-1After 200 cycles, 97.8% of the capacity remained.

The invention has the beneficial effects that:

(1) the electrode material provided by the invention is used as a lithium ion battery cathode material, and has the advantages of high theoretical specific capacity, high safety performance, high reversible specific capacity, high coulombic efficiency, excellent cycle performance and the like.

(2) The preparation method provided by the invention is simple in synthesis process, is suitable for charging and discharging high-power devices such as electric automobiles and the like, and has wide application prospects in the field of lithium ion batteries.

(3) The invention provides more choices for the application of the M-Nb-O material to the lithium ion battery cathode material, has wide application prospect in the field of the application of the lithium ion battery to the electric automobile, and accelerates the popularization of the electric automobile.

Drawings

Fig. 1 is a flow chart illustrating mixing performed by a solid-phase reaction method in a method for preparing an electrode material for a secondary lithium ion battery according to an embodiment of the present invention;

fig. 2 is a flow chart illustrating mixing by an electrostatic spinning method in a method for preparing an electrode material for a secondary lithium ion battery according to an embodiment of the present invention;

FIG. 3 shows AlNb obtained in examples 1, 2, 3, 21, 22 and 23₁₁O₂₉，GaNb₁₁O₂₉And CrNb₁₁O₂₉XRD pattern of (a);

FIG. 4 shows an embodiment1 obtaining AlNb₁₁O₂₉Electron micrographs of (a);

FIG. 5 is a GaNb sample obtained in example 2₁₁O₂₉Electron micrographs of (a);

FIG. 6 shows CrNb obtained in example 3₁₁O₂₉Electron micrographs of (a);

FIG. 7 shows AlNb obtained in example 21₁₁O₂₉Electron micrographs of (a);

FIG. 8 shows example 22, a GaNb₁₁O₂₉Electron micrographs of (a);

FIG. 9 shows example 23, in which CrNb is obtained₁₁O₂₉Electron micrographs of (a);

FIG. 10 shows AlNb obtained in example 1₁₁O₂₉The rate capability of (a);

FIG. 11 shows AlNb obtained in example 21₁₁O₂₉The rate capability of (a);

FIG. 12 is a GaNb sample obtained in example 2₁₁O₂₉The rate capability of (a);

FIG. 13 is a GaNb sample obtained in example 22₁₁O₂₉The rate capability of (a);

FIG. 14 shows CrNb obtained in example 3₁₁O₂₉The rate capability of (a);

FIG. 15 shows CrNb obtained in example 23₁₁O₂₉The rate capability of (a);

FIG. 16 shows AlNb obtained in examples 1 and 21₁₁O₂₉Cycling performance at 10C;

FIG. 17 shows GaNb obtained in examples 2 and 22₁₁O₂₉Cycling performance at 10C;

FIG. 18 shows CrNb obtained in examples 3 and 23₁₁O₂₉Cycling performance at 10C.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The flow chart of the solid phase reaction method adopted by the invention is shown in figure 1; the flow chart of the electrospinning method is shown in FIG. 2.

Example 1

Mixing niobium pentoxide and aluminum oxide according to the element molar ratio Al to Nb of 1 to 11 by adopting a high-energy ball mill ball milling method, and sintering at 1200 ℃ for 6 hours to obtain AlNb₁₁O₂₉And (3) powder.

Example 2

Mixing niobium pentoxide and gallium trioxide according to the element molar ratio Ga: Nb 1:11 by adopting a high-energy ball mill ball milling method, and sintering at 1300 ℃ for 6 h to obtain GaNb₁₁O₂₉And (3) powder.

Example 3

Mixing niobium pentoxide and chromium trioxide according to the element molar ratio Cr to Nb being 1:11 by adopting a high-energy ball mill ball milling method, and sintering at 1300 ℃ for 6 h to obtain CrNb₁₁O₂₉And (3) powder.

Electrode materials were prepared by the solid phase method, examples 4-20 are shown in Table 1.

TABLE 1

Example 21

S11: dissolving 0.001 mol of aluminum acetylacetonate, 2 mL of acetic acid and 1 g of polyvinylpyrrolidone in 10 mL of N, N-dimethylformamide to form an aluminum solution;

s12: dissolving 0.011 mol niobium ethoxide in 5 mL ethanol to form a niobium solution;

s13: uniformly mixing an aluminum solution and a niobium solution, carrying out electrostatic spinning to obtain fibers, wherein the diameter of a needle is 21G, the capacity of an injector is 10 mL, the distance between the needle and a receiving plate is 15 cm, the flow rate of the solution is 0.5 mm per minute, the voltage is 15 kV, and the fibers are dried at the temperature of 80 ℃;

s14: sintering the fiber at 800 ℃ for 3 h to obtainElectrode material AlNb₁₁O₂₉And (3) powder.

Example 22

S11: dissolving 0.001 mol of gallium acetylacetonate, 2 mL of acetic acid and 1 g of polyvinylpyrrolidone in 10 mL of N, N-dimethylformamide to form a gallium solution;

s13: uniformly mixing a gallium solution and a niobium solution, carrying out electrostatic spinning to obtain a fiber, wherein the diameter of a needle is 21G, the capacity of an injector is 10 mL, the distance between the needle and a receiving plate is 15 cm, the flow rate of the solution is 0.5 mm per minute, the voltage is 15 kV, and the fiber is dried at the temperature of 80 ℃;

s14: sintering the fibers at 800 ℃ for 3 h to obtain an electrode material GaNb₁₁O₂₉And (3) powder.

Example 23

S11: dissolving 0.001 mol of chromium acetylacetonate, 2 mL of acetic acid and 1 g of polyvinylpyrrolidone in 10 mL of N, N-dimethylformamide to form a gallium solution;

s13: uniformly mixing the chromium solution and the niobium solution, carrying out electrostatic spinning to obtain fibers, wherein the diameter of a needle is 21G, the capacity of an injector is 10 mL, the distance between the needle and a receiving plate is 15 cm, the flow rate of the solution is 0.5 mm per minute, the voltage is 15 kV, and drying the fibers at 80 ℃;

s14: sintering the fiber at 800 ℃ for 3 h to obtain an electrode material CrNb₁₁O₂₉And (3) powder.

Electrode materials were prepared by electrospinning, examples 24-47 are shown in Table 2.

TABLE 2

(Takeda)

FIG. 3 shows AlNb prepared by the methods of example 1, example 2, example 3, example 21, example 22 and example 23₁₁O₂₉、GaNb₁₁O₂₉And CrNb₁₁O₂₉The XRD pattern of the AlNb is analyzed to obtain the AlNb prepared by the solid phase method and the electrostatic spinning method₁₁O₂₉、GaNb₁₁O₂₉And CrNb₁₁O₂₉The materials are pure, which shows that the solid phase method and the electrostatic spinning method can successfully prepare the AlNb₁₁O₂₉、GaNb₁₁O₂₉And CrNb₁₁O₂₉Three materials. FIGS. 4, 5 and 6 show that AlNb is obtained by the methods of examples 1, 2 and 3₁₁O₂₉、GaNb₁₁O₂₉And CrNb₁₁O₂₉The electron micrograph shows that the three materials are rod-shaped particles with uniform size and the particle diameter is between 0.2 and 20 mu m. FIGS. 7, 8 and 9 show that AlNb is obtained by the methods of examples 21, 22 and 23₁₁O₂₉、GaNb₁₁O₂₉And CrNb₁₁O₂₉The electron micrograph of (A) shows that AlNb is present₁₁O₂₉、GaNb₁₁O₂₉And CrNb₁₁O₂₉The materials are all nano fibers, and the diameters of the fibers are about 400nm, 250nm and 200nm respectively. FIGS. 10 and 11 show AlNb obtained by the methods described in examples 1 and 21, respectively₁₁O₂₉FIG. 12 and FIG. 13 are graphs showing the magnification of GaNb obtained by the methods of examples 2 and 22₁₁O₂₉Magnification graph of (1). FIG. 14 and FIG. 15 show CrNb obtained by the methods described in examples 3 and 23, respectively₁₁O₂₉Magnification graph of (1). AlNb prepared by solid phase method₁₁O₂₉The first coulombic efficiency of charge and discharge under 0.1C multiplying power is as high as 96.3 percent, and the reversible specific capacity is as high as 257 mAh g^-1The reversible specific capacity is still 67 mAh g under the multiplying power of 10C^-1. GaNb prepared by solid phase method₁₁O₂₉The first coulombic efficiency of charge and discharge under 0.1C multiplying power is as high as 94.4 percent, and the reversible specific capacity is as high as 255 mAhg^-1The reversible specific capacity is still 124 mAh g under the multiplying power of 10C^-1. CrNb prepared by solid phase method₁₁O₂₉The first coulombic efficiency of charge and discharge under 0.1C multiplying power is as high as 93.8 percent, and the reversible capacity ratio is as high as 278 mAh g^-1The reversible specific capacity is still 148 mAh g under the multiplying power of 10C^-1. AlNb prepared by electrostatic spinning method₁₁O₂₉The first coulombic efficiency of charge and discharge under 0.1C multiplying power is as high as 90.4 percent, and the reversible specific capacity is as high as 253mAh g^-1The reversible specific capacity is still 123 mAh g under the multiplying power of 10C^-1. GaNb prepared by electrostatic spinning method₁₁O₂₉The first coulombic efficiency of charge and discharge under 0.1C multiplying power is as high as 96.4 percent, and the reversible specific capacity is as high as 276 mAh g^-1The reversible specific capacity is still 174 mAh g under the multiplying power of 10C^-1. CrNb prepared by electrostatic spinning method₁₁O₂₉The first coulombic efficiency of charge and discharge under 0.1C multiplying power is as high as 94.9 percent, and the reversible specific capacity is as high as 368 mAh g^-1The reversible specific capacity is still 184 mAh g under the multiplying power of 10C^-1. The materials have excellent rate performance and are very suitable for being applied to lithium ion batteries for electric automobiles. FIG. 16, FIG. 17, and FIG. 18 show AlNb obtained by the methods described in examples 1, 21, 2, 22, 3, and 23, respectively₁₁O₂₉、GaNb₁₁O₂₉And CrNb₁₁O₂₉The AlNb prepared by the solid phase method after 200 cycles at 10 ℃ is shown in the cycle chart₁₁O₂₉Still has 83.3 percent of specific capacity, and the AlNb is prepared by an electrostatic spinning method₁₁O₂₉The material still had a specific capacity of 94.3%. GaNb prepared by solid phase method₁₁O₂₉Still has 97.5 percent of specific capacity, and the GaNb is prepared by an electrostatic spinning method₁₁O₂₉The material still had a specific capacity of 98.3%. CrNb prepared by solid phase method₁₁O₂₉CrNb prepared by electrostatic spinning method with specific capacity still 96.1%₁₁O₂₉The material still had a specific capacity of 97.8%. The materials show excellent cycle performance, and can fully meet the requirement of the lithium ion battery for the electric automobile on the cycle performance. All the above advantages are fully explained by AlNb₁₁O₂₉、GaNb₁₁O₂₉And CrNb₁₁O₂₉Is a promising power battery cathode material.

It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims

1. The electrode material of the lithium ion battery is characterized in that the chemical formula of the electrode material is MNb₁₁O₂₉And M is Al, Ga or Cr.

2. A method for preparing the electrode material according to claim 1, comprising a solid-phase reaction method or an electrospinning method;

the solid phase reaction method comprises the following steps:

the electrostatic spinning method comprises the following steps:

3. The production method according to claim 2, wherein the aluminum source is an aluminum oxide or an aluminum salt; the gallium source is gallium sesquioxide or gallium salt; the chromium source is chromium oxide or chromium salt;

4. The production method according to any one of claims 2 to 3, wherein the niobium source is niobium pentoxide, niobium powder, niobium oxalate or niobium ethoxide.

5. The method of claim 2, wherein the electrospinning conditions are: the diameter of the needle is 21G, the capacity of the syringe is 10 mL, the distance between the needle and the receiving plate is 15 cm, the flow rate of the solution is 0.5 mm per minute, and the voltage is 15 kV.

6. The method of claim 2, wherein the anti-hydrolysis agent is acetic acid or citric acid.

7. The method according to claim 2, wherein the binder is polyvinylpyrrolidone or polyacrylonitrile.

8. The method according to claim 2, wherein the organic solvent is N, N-dimethylformamide or ethanol.

9. The method of claim 2, wherein the temperature of the drying is 80 ℃; the sintering temperature is 750-1400 ℃, and the sintering time is 2-6 h.