CN104009238A - A method for in-situ synthesis of rutile TiO2 mesogen and graphene composite - Google Patents

Abstract

The invention discloses a method for in-situ synthesis of compound of rutile TiO2 mesocrystal and graphene. A simple hydrothermal method is adopted to carry out in-situ synthesis on the compound of the rutile TiO2 mesocrystal and the graphene, and the compound of the rutile TiO2 mesocrystal and the grapheme is used for assembling lithium ion batteries. The method for the in-situ synthesis of the compound of the rutile TiO2 mesocrystal and the grapheme is simple in preparation, cost is low, energy consumption is low, repeatability is good, and the manufactured lithium ion batteries have high specific capacity and long-range cycling stability, show excellent multiplying power charge-discharge properties, and have wide commercial prospects.

Description

A method for in-situ synthesis of rutile TiO2 mesogen and graphene composite

technical field

The invention belongs to the field of electrode material preparation, in particular to a method for in-situ synthesis of rutile _TiO2 mesogen and graphene composite.

Background technique

Lithium-ion battery is a green, high-energy and environment-friendly battery that appeared in the 1990s. It has been widely used due to its outstanding advantages. At present, lithium-ion batteries and their key materials have become a technological and industrial focus of all countries in the world. They are also one of the energy sources that our government attaches great importance to development and utilization, and have been included in the national medium and long-term development plan. In particular, the development of lithium-ion power batteries suitable for electric vehicles (EV) and hybrid electric vehicles (HEV) has become the hottest and fastest-growing research field in the field of new energy in recent years. The negative electrode materials commonly used in industry now include metal lithium, carbon materials, Li ₄ Ti ₅ O ₁₂ and so on. However, due to the disadvantages of lithium metal and carbon materials such as potential safety hazards, poor rate performance, and difficult synthesis of Li ₄ Ti ₅ O ₁₂ , their large-scale applications are limited. TiO ₂ is one of the most popular anode materials for lithium-ion batteries.

Contents of the invention

The purpose of the present invention is to provide a method for in-situ synthesis of rutile _TiO2 mesogen and graphene composite, which has the advantages of simple preparation method, low cost, low energy consumption and good reproducibility, and the obtained lithium ion battery has high Excellent specific capacity and long-range cycle stability, as well as excellent rate charge and discharge performance, have broad commercial prospects.

To achieve the above object, the present invention adopts the following technical solutions:

A kind of in _- situ synthesis rutile TiO The method for mesogen and graphene compound comprises the following steps:

(1) Disperse dodecylbenzenesulfonic acid in nitric acid solution;

(2) After a uniform emulsion is formed, add the graphene oxide solution dropwise, stir evenly, and finally add tetrabutyl titanate, and continue stirring evenly;

(3) After hydrothermal reaction, centrifugation, washing and drying, the composite of rutile TiO ₂ mesocrystal and graphene oxide was prepared;

(4) Disperse the composite of rutile TiO ₂ mesogen and graphene oxide in water, and obtain the composite of rutile TiO ₂ mesogen and graphene after hydrothermal reaction, centrifugation, washing and drying.

The amount of dodecylbenzenesulfonic acid added in step (1) is 0.5-5 mL; the concentration of the nitric acid solution is 0.5-6 mol/L.

The amount of graphene oxide added in step (2) is 5-40 mg, and the amount of tetrabutyl titanate added is 0.5-2 mL.

The hydrothermal reaction temperature in step (3) is 50-90°C, and the reaction time is 3-72 h.

The hydrothermal reaction temperature in step (4) is 120-180°C.

Described rutile TiO ₂ mesogen and graphene composite are used for assembling lithium-ion battery: rutile TiO ₂ mesocrystal and graphene composite, polyvinylidene fluoride and acetylene black are mixed and ground in a mass ratio of 8:1:1 Evenly coated on the copper foil, after drying as the negative electrode, metal lithium as the positive electrode, LiPF ₆ /EC-EMC-DMC solution as the electrolyte, and assembled into a lithium-ion battery in a glove box.

The concentration of LiPF ₆ in the LiPF ₆ /EC-EMC-DMC solution is 1 mol/L, wherein the volume ratio of EC, EMC and DMC is 1:1:1.

Significant advantage of the present invention is:

(1) The present invention provides a method for in-situ synthesis of rutile _TiO2 mesogen and graphene composites, which is simple to operate, low in cost, low in energy consumption, good in reproducibility, and has good application value.

(2) The prepared rutile TiO ₂ mesogen and graphene composite is used as the negative electrode of the lithium-ion battery. The assembled lithium-ion battery has high specific capacity and long-term cycle stability, and the current density is 3.4 A/g At the same time, it also exhibits excellent rate discharge performance, even when the current density is 6.8 A/g, its charge and discharge capacity is also low. It can be stabilized at 139.6 mA h/g.

Description of drawings

Fig. 1 is the scanning electron micrograph and the transmission electron micrograph of the rutile _TiO2 mesogen and graphene composite prepared in embodiment 1.

Figure 2 is the cycle performance curves of the lithium-ion battery assembled with the rutile TiO ₂ mesogen and graphene composite prepared in Example 1 at different rates (1C=170 mA/g).

Detailed ways

Example 1

A kind of rutile TiO The preparation method of _mesocrystal and graphene compound, comprises the following steps:

1) Disperse 0.68 mL of dodecylbenzenesulfonic acid in 70 mL of 2 mol/L nitric acid solution;

2) After a uniform emulsion is formed, add 2 mL graphene oxide solution (5 mg/mL) dropwise, stir evenly, and finally add 0.68 mL tetrabutyl titanate dropwise, and continue stirring evenly;

3) The resulting mixture was reacted in a water bath at 70 °C for 48 h, taken out, naturally cooled to room temperature, centrifuged to separate the product, washed 5 times with alcohol water, and dried to obtain a composite of rutile TiO ₂ mesogen and graphene oxide .

4) Weigh 100 mg of rutile TiO ₂ mesogen and graphene oxide composite and disperse it in 35 mL of water, put it into a reaction kettle, put it in a 140 °C oven, react for 6 h, take it out, cool it naturally to room temperature, and centrifuge the product. After washing with alcohol water for 3 times and drying, the composite of rutile TiO ₂ mesogen and graphene was obtained.

Gained rutile TiO ₂ mesogen and graphene composite are used for assembling lithium-ion battery, and its assembly method comprises: rutile TiO ₂ mesocrystal and graphene composite, polyvinylidene fluoride and acetylene black are 8:1 by mass ratio :1 mixed and ground evenly, coated on copper foil, used as negative electrode after vacuum drying, metal lithium as positive electrode, 1 mol/L LiPF ₆ /EC-EMC-DMC (1:1:1, v/v/v ) solution is used as the electrolyte, and the lithium-ion battery is assembled in a glove box.

It can be seen from the scanning electron microscope that the rutile TiO ₂ mesocrystal is cylindrical and composed of ultrafine small grains. It can be clearly seen from the TEM image that the rutile TiO ₂ mesocrystal is surrounded by ultrathin graphene nanosheets, and the size of the rutile TiO ₂ mesocrystal is 100-200 nm.

The lithium-ion battery assembled in this example has a capacity of more than 150 mA h/g for 1000 cycles of charge and discharge at a current density of 3.4 A/g, and has excellent long-term cycle performance; at the same time, it also exhibits excellent rate discharge performance , the charge-discharge capacity is stable at 139.6 mA h/g even at a current density of 6.8 A/g.

Example 2

A kind of rutile TiO The preparation method of _mesocrystal and graphene compound, comprises the following steps:

1) Disperse 1.035 mL of dodecylbenzenesulfonic acid in 70 mL of 2 mol/L nitric acid solution;

2) After a uniform emulsion is formed, add 3 mL graphene oxide solution (5 mg/mL) dropwise, stir evenly, and finally add 0.68 mL tetrabutyl titanate dropwise, and continue stirring evenly;

3) The resulting mixture was reacted in a water bath at 70 °C for 48 h, taken out, naturally cooled to room temperature, centrifuged to separate the product, washed 5 times with alcohol water, and dried to obtain a composite of rutile TiO ₂ mesogen and graphene oxide .

4) Weigh 100 mg of rutile TiO ₂ mesogen and graphene oxide composite and disperse it in 35 mL of water, put it into a reaction kettle, put it in a 140 °C oven, react for 6 h, take it out, cool it naturally to room temperature, and centrifuge the product. After washing with alcohol water for 3 times and drying, the composite of rutile TiO ₂ mesogen and graphene was obtained.

Gained rutile TiO ₂ mesogen and graphene composite are used for assembling lithium-ion battery, and its assembly method comprises: rutile TiO ₂ mesocrystal and graphene composite, polyvinylidene fluoride and acetylene black are 8:1 by mass ratio :1 mixed and ground evenly, coated on copper foil, used as negative electrode after vacuum drying, metal lithium as positive electrode, 1 mol/L LiPF ₆ /EC-EMC-DMC (1:1:1, v/v/v ) solution is used as the electrolyte, and the lithium-ion battery is assembled in a glove box.

The lithium-ion battery assembled in this example has a capacity of more than 150 mA h/g for 1000 cycles of charge and discharge at a current density of 3.4 A/g, and has excellent long-term cycle performance; at the same time, it also exhibits excellent rate discharge performance , the charge-discharge capacity is stable at 139.6 mA h/g even at a current density of 6.8 A/g.

Example 3

A kind of rutile TiO The preparation method of _mesocrystal and graphene compound, comprises the following steps:

1) Disperse 0.68 mL of dodecylbenzenesulfonic acid in 70 mL of 4 mol/L nitric acid solution;

2) After a uniform emulsion is formed, add 2 mL graphene oxide solution (5 mg/mL) dropwise, stir evenly, and finally add 0.68 mL tetrabutyl titanate dropwise, and continue stirring evenly;

3) The resulting mixture was reacted in a water bath at 70 °C for 72 h, taken out, cooled naturally to room temperature, centrifuged to separate the product, washed 5 times with alcohol water, and dried to obtain a composite of rutile TiO ₂ mesogen and graphene oxide .

4) Weigh 100 mg of rutile TiO ₂ mesogen and graphene oxide composite and disperse it in 35 mL of water, put it into a reaction kettle, put it in a 140 °C oven, react for 6 h, take it out, cool it naturally to room temperature, and centrifuge the product. After washing with alcohol water for 3 times and drying, the composite of rutile TiO ₂ mesogen and graphene was obtained.

Gained rutile TiO ₂ mesogen and graphene composite are used for assembling lithium-ion battery, and its assembly method comprises: rutile TiO ₂ mesocrystal and graphene composite, polyvinylidene fluoride and acetylene black are 8:1 by mass ratio :1 mixed and ground evenly, coated on copper foil, used as negative electrode after vacuum drying, metal lithium as positive electrode, 1 mol/L LiPF ₆ /EC-EMC-DMC (1:1:1, v/v/v ) solution is used as the electrolyte, and the lithium-ion battery is assembled in a glove box.

The lithium-ion battery assembled in this example has a capacity of more than 150 mA h/g for 1000 cycles of charge and discharge at a current density of 3.4 A/g, and has excellent long-term cycle performance; at the same time, it also exhibits excellent rate discharge performance , the charge-discharge capacity is stable at 139.6 mA h/g even at a current density of 6.8 A/g.

The above descriptions are only preferred embodiments of the present invention, and all equivalent changes and modifications made according to the scope of the patent application of the present invention shall fall within the scope of the present invention.

Claims (10)

1. an original position titania TiO ₂the method of mesomorphic and graphene complex, is characterized in that: adopt simple hydro thermal method original position to prepare rutile TiO ₂mesomorphic and graphene complex.

2. original position titania TiO according to claim 1 ₂the method of mesomorphic and graphene complex, is characterized in that: comprise the following steps:

(1) DBSA is scattered in salpeter solution;

(2) after uniform emulsion to be formed, drip graphene oxide solution, stir, finally splash into butyl titanate, continue to stir;

(3) through hydro-thermal reaction, centrifugal, washing, dry, make rutile TiO ₂mesomorphic and graphene oxide compound;

(4) by rutile TiO ₂mesomorphic and graphene oxide compound are dispersed in water, and after hydro-thermal reaction, centrifugal, washing, drying, obtain rutile TiO ₂mesomorphic and graphene complex.

3. original position titania TiO according to claim 2 ₂the method of mesomorphic and graphene complex, is characterized in that: in step (1), the addition of DBSA is 0.5-5 mL; The concentration of salpeter solution is 0.5-6 mol/L.

4. original position titania TiO according to claim 2 ₂the method of mesomorphic and graphene complex, is characterized in that: in step (2), the addition of graphene oxide is 5-40 mg, and the addition of butyl titanate is 0.5-2 mL.

5. original position titania TiO according to claim 2 ₂the method of mesomorphic and graphene complex, is characterized in that: the described hydrothermal temperature of step (3) is 50-90 DEG C, and the reaction time is 3-72 h.

6. original position titania TiO according to claim 2 ₂the method of mesomorphic and graphene complex, is characterized in that: the described hydrothermal temperature of step (4) is 120-180 DEG C.

7. the rutile TiO that the method for claim 1 makes ₂mesomorphic and graphene complex.

8. the rutile TiO that the method for claim 1 makes ₂the application of mesomorphic and graphene complex, is characterized in that: described rutile TiO ₂mesomorphic and graphene complex is used for assembling lithium ion battery.

9. rutile TiO according to claim 8 ₂the application of mesomorphic and graphene complex, is characterized in that: the assemble method of described lithium ion battery comprises: by rutile TiO ₂mesomorphic and graphene complex, Kynoar and acetylene black are in mass ratio for 8:1:1 mixed grinding is evenly coated on Copper Foil, to be dried rear as negative pole, using lithium metal as positive pole, by LiPF ₆/ EC-EMC-DMC solution, as electrolyte, is assembled into lithium ion battery in glove box.

10. rutile TiO according to claim 8 ₂the application of mesomorphic and graphene complex, is characterized in that: described LiPF ₆liPF in/EC-EMC-DMC solution ₆concentration be 1 mol/L, wherein the volume ratio of EC, EMC and DMC is 1:1:1.