CN106941155B - A rare earth hydride-carbon nanocomposite material and its preparation method and application - Google Patents

Abstract

The invention provides a rare earth hydride-carbon nanocomposite material and its preparation method and application. Rare earth hydrides are prepared by high temperature and high pressure, and the rare earth hydrides and carbon materials are uniformly prepared in a certain proportion by ball milling at room temperature and low speed. mix. The method has the advantages of being simple and fast, high yield, low cost, and easy to scale up production. The reaction product is uniformly mixed, small in particle size, high in purity, has a specific synergistic effect, and has a high lithium storage specific capacity. Just because the present invention has the above remarkable advantages, it has great industrial application prospects.

Description

A rare earth hydride-carbon nanocomposite material and its preparation method and application

technical field

The invention belongs to the field of lithium-ion battery electrode materials, and relates to a rare earth hydride-carbon nanocomposite material and a preparation method and application thereof.

Background technique

As an important chemical energy storage technology, lithium-ion batteries have been extensively researched and developed in the past two decades due to their advantages such as high energy storage density, long cycle life, and low self-discharge rate, and are now widely used for various portable devices.

At present, the most common anode material for commercial lithium-ion batteries is graphite anode material, which is low in cost, but it is easy to form SEI (Solid Electrolyte Interface) layer with electrolyte during charging, which reduces its Coulombic efficiency, and the natural graphite material theory The low lithium storage capacity leads to the fact that the energy density of lithium ions does not meet its long-term development.

In view of the above problems, people have carried out research and improvement on lithium-ion battery anode materials. Carbon nanocomposites have attracted extensive attention and research because of their unique chemical properties and structure, good electrical properties and lithium storage capacity. Chinese patents CN103633292B, CN103022414B, etc. all introduce several carbon nanocomposite negative electrodes with special structures. However, the preparation methods of these anode materials are complicated, the cost is high, and the yield is low, which is not conducive to large-scale production and commercial application.

In view of this, it is necessary to develop a lithium-ion battery anode with both higher capacity and lower cost.

Contents of the invention

The invention provides a rare earth hydride-carbon nanocomposite material and its preparation method and application. The material is innovatively compounded with a rare earth hydride and a carbon material, and the two are uniformly mixed and subjected to nano-processing, and the obtained material is Medium rare earth hydrides and carbon materials have a synergistic effect and are used as anode materials for lithium-ion batteries, with high lithium storage specific capacity. At the same time, the preparation method of the composite material is simple, the conditions are relatively mild, and can be used for mass production. The prepared composite material is evenly composited, small in size, and the ratio can be adjusted, which can expand production.

In order to achieve the above object, the present invention adopts the following technical solutions:

A preparation method of a rare earth hydride-carbon nanocomposite material, the specific steps are as follows:

(1) make the rare earth metal absorb hydrogen to obtain the rare earth hydride;

(2) Mixing and ball milling the rare earth hydride obtained in step (1) with the carbon material to obtain the rare earth hydride-carbon nanocomposite material.

The hydrogen purity in the step (1) of the above method is above 99.999%.

The whole process of steps (1) and (2) of the above method is carried out in an anhydrous and oxygen-free environment.

The rare earth metals mentioned in the above method step (1) include but not limited to: metal yttrium (Y), metal lanthanum (La), metal cerium (Ce), metal praseodymium (Pr), metal gadolinium (Gd).

The reaction conditions for hydrogen absorption of the rare earth metal in step (1) of the above method are: reaction temperature 250°C-400°C, reaction pressure 3MPa-4MPa hydrogen pressure, reaction time 2h-10h, preferably temperature 350°C, pressure 4MPa, preferably Time 3h-5h.

The carbon material described in step (2) of the above method includes but is not limited to: amorphous carbon, graphite, expanded graphite, graphene, porous carbon and the like.

The weight ratio of the rare earth hydride to the carbon material in step (2) of the above method is 1:0.1-1:10.

In step (2) of the above method, a planetary ball mill is used for ball milling, the ball-to-material ratio is 30:1-120:1, preferably 45:1-60:1, and the ball milling time is 10min-3000min, preferably 60-300min.

The ball milling in step (2) of the above method is carried out at a rotating speed of 200rpm-250rpm.

The ball milling in step (2) of the above method is carried out at room temperature (15-35° C.) under 0.3MPa-0.4MPa hydrogen pressure.

The above method also includes taking out and collecting the rare earth hydride-carbon nanocomposite material sample in a glove box filled with argon.

The invention also provides the rare earth hydride-carbon nanocomposite material prepared by the above method.

The present invention also provides the application of the above-mentioned rare earth hydride-carbon nanocomposite material in the lithium ion battery negative electrode.

Technical effect of the present invention

The invention provides a rare earth hydride-carbon nanocomposite material and its preparation method and application. Rare earth hydrides are prepared by high temperature and high pressure, and the rare earth hydrides and carbon materials are uniformly prepared in a certain ratio by ball milling at room temperature. mix. The method has the advantages of being simple and fast, high yield, low cost, and easy to scale up production. The reaction product is uniformly mixed, small in particle size, high in purity, has a specific synergistic effect, and has a high lithium storage specific capacity. Just because the present invention has the above very remarkable advantages, it has great industrial application prospects.

Description of drawings

Fig. 1. The powder X-ray diffraction pattern of YH ₃ -graphite weight ratio prepared in Example 1 is 1:2 nanocomposite material.

Fig. 2. The transmission electron microscope image of the YH ₃ -graphite nanocomposite material with a weight ratio of 1:2 prepared in Example 1.

Fig. 3. Cyclic lithium storage performance of the YH ₃ -graphite nanocomposite with a weight ratio of 1:2 prepared in Example 1.

Detailed ways

The present invention will be described in detail below by way of examples. However, the content of the present invention is not limited to these examples. Among them, rare earth metals were purchased from Beijing Institute of Nonferrous Metals, and commercial carbon materials were purchased from Sinopharm Chemical Reagent Co., Ltd. and Shenzhen Tianchenghe Technology Co., Ltd. The model of the planetary ball mill used was FRITSCH, pulveriszttz5.

Example 1

YH ₃ - graphite weight ratio of 1:2 nanocomposite

(1) Take 2g metal Y block, polish it to remove the oxide layer on the surface, place it in a tube furnace, and react with hydrogen absorption for 3 hours at 350°C and 3MPa hydrogen pressure to obtain YH ₃ powder.

(2) Take 200 mg of YH ₃ powder, mix with 400 mg of 300 mesh graphite powder (purchased from Sinopharm Group), add 30 g of zirconia balls, fill the ball mill with 0.4 MPa of hydrogen, and use a planetary ball mill for 150 min to mill at a speed of 200 rpm.

(3) Use a vacuum pump to evacuate the ball mill jar to a vacuum, put it in a glove box filled with argon and open it, take out the obtained mixed material with a spoon, and store it in the glove box.

The X-ray diffraction and transmission electron microscopy of the YH ₃ -graphite nanocomposite obtained after the above three steps are shown in Figure 1 and Figure 2, as can be seen from the figure, the crystallinity of YH ₃ and graphite is better, and YH ₃ The particle size is about 500nm, and presents a uniform mosaic structure. The material is used as the negative electrode of lithium-ion battery, and its charging and discharging performance is tested as shown in Figure 3. After 250 cycles of charging and discharging, the average mass specific capacity is about 700mAh/g, and it remains relatively stable.

Example 2

YH ₃ - expanded graphite weight ratio 1:0.2 nanocomposite

(1) Take 2g metal Y block, grind off the oxide layer on the surface, put it in a tube furnace, and react with hydrogen absorption for 4h at 350°C and 4MPa hydrogen pressure to obtain YH ₃ powder.

(2) Take 500 mg of YH ₃ powder, mix with 100 mg of 200 mesh expanded graphite powder (purchased from Sinopharm Group), add 30 g of zirconia balls, fill the ball mill with 0.4 MPa of hydrogen, and use a planetary ball mill to mill for 60 min at a speed of 200 rpm.

(3) Use a vacuum pump to evacuate the ball mill jar to a vacuum, put it in a glove box filled with argon and open it, take out the obtained mixed material with a spoon, and store it in the glove box.

In the YH ₃ -expanded graphite nanocomposite material obtained after the above three steps, YH ₃ has good crystallinity and a particle size of about 200nm, and is uniformly mixed with the expanded graphite.

Example 3

LaH ₃ -graphite nanocomposites with a weight ratio of 1:1

(1) Take 2g of metal La block, polish it to remove the oxide layer on the surface, place it in a tube furnace, and react with hydrogen absorption for 3 hours at 350°C and 3.5MPa hydrogen pressure to obtain LaH ₃ powder.

(2) Take 200mg of _LaH3 powder, mix with 200mg of 300 mesh graphite powder (purchased from Sinopharm Group), add 18g of zirconia balls, fill the ball mill with 0.4MPa hydrogen, and use a planetary ball mill to mill for 300min at a speed of 250rpm.

(3) Use a vacuum pump to evacuate the ball mill jar to a vacuum, put it in a glove box filled with argon and open it, take out the obtained mixed material with a spoon, and store it in the glove box.

In the LaH ₃ -graphite nanocomposite material obtained after the above three steps, LaH ₃ has good crystallinity, a particle size of about 500 nm, and is uniformly mixed with graphite.

Example 4

GdH ₃ -graphene nanocomposites with a weight ratio of 1:10

(1) Take 3g of metal Gd block, polish to remove the oxide layer on the surface, put it in a tube furnace, and react with hydrogen absorption for 3h at 400°C and 4MPa hydrogen pressure to obtain GdH3 powder.

(2) Take 20 mg of GdH ₃ powder, mix it with 200 mg of Xianfeng Nano-XF001H chemical method graphene (purchased from Sinopharm Group), add 10 g of zirconia balls, fill the ball mill with 0.35 MPa of hydrogen, and use a planetary ball mill to mill for 150 minutes. The rotational speed is 200rpm.

(3) Use a vacuum pump to evacuate the ball mill jar to a vacuum, put it in a glove box filled with argon and open it, take out the obtained mixed material with a spoon, and store it in the glove box.

In the GdH ₃ -graphene nanocomposite material obtained after the above three steps, GdH ₃ has good crystallinity, a particle size of about 500 nm, and is uniformly mixed with graphene.

Example 5

PrH ₃ -CNT nanocomposites with a weight ratio of 1:5

(1) Take 3g of metal Pr block, polish it to remove the oxide layer on the surface, place it in a tube furnace, and react with hydrogen absorption for 5h at 400°C and 4MPa hydrogen pressure to obtain _PrH3 powder.

(2) Take 40 mg of PrH ₃ powder, mix it with 200 mg of TNIM8 carbon nanotubes (purchased from Sinopharm Group), add 15 g of zirconia balls, fill the ball mill with 0.4 MPa of hydrogen, and use a planetary ball mill for 300 min to mill at a speed of 225 rpm.

(3) Use a vacuum pump to evacuate the ball mill jar to a vacuum, put it in a glove box filled with argon and open it, take out the obtained mixed material with a spoon, and store it in the glove box.

In the PrH ₃ -carbon nanotube composite material obtained after the above three steps, PrH ₃ has good crystallinity, a particle size of about 500 nm, and is uniformly mixed with carbon nanotubes.

Example 6

CeH ₃ -porous carbon nanocomposites with a weight ratio of 1:2

(1) Take 3g of metal Ce block, grind off the oxide layer on the surface, put it in a tube furnace, and react with hydrogen absorption for 5h at 400°C and 4MPa hydrogen pressure to obtain CeH ₃ powder.

(2) Take 200mg of CeH ₃ powder, mix it with 400mg of porous carbon Ketjen Black 600 (purchased from Tianchenghe Technology), add 30g of zirconia balls, fill the ball mill with 0.3MPa hydrogen, and use a planetary ball mill to mill for 150min at a speed of 250rpm.

(3) Use a vacuum pump to evacuate the ball mill jar to a vacuum, put it in a glove box filled with argon and open it, take out the obtained mixed material with a spoon, and store it in the glove box.

In the CeH ₃ -porous carbon composite material obtained after the above three steps, CeH ₃ has good crystallinity, a particle size of about 500 nm, and is uniformly mixed with the porous carbon.

Claims (7)

1. A method for preparing a rare earth hydride-carbon nanocomposite material applied to lithium-ion battery negative pole, the specific steps are as follows: (1) make the rare earth metal absorb hydrogen to obtain the rare earth hydride; (2) The rare earth hydride obtained in step (1) is mixed with the carbon material and ball milled to obtain a rare earth hydride-carbon nanocomposite material. The ball mill is at a speed of 200rpm-250rpm, 15-35°C, 0.3MPa- Under 0.4MPa hydrogen pressure; where, The rare earth hydride is YH ₃ , LaH ₃ , GdH ₃ , PrH ₃ or CeH ₃ . 2. a kind of preparation method that is applied to the rare earth hydride-carbon nanocomposite material of lithium-ion battery negative pole as claimed in claim 1, it is characterized in that, the reaction condition of the described rare earth metal hydrogen absorption of step (1) is: react The temperature is 250°C-400°C, the reaction pressure is 3MPa-4MPa hydrogen pressure, and the reaction time is 2h-10h. 3. a kind of preparation method that is applied to the rare earth hydride-carbon nanocomposite material of lithium-ion battery negative pole as claimed in claim 1, it is characterized in that, the carbon material described in step (2) comprises: amorphous carbon, Graphite, expanded graphite, graphene or porous carbon. 4. a kind of preparation method that is applied to the rare earth hydride-carbon nanocomposite material of negative pole of lithium ion battery as claimed in claim 1, is characterized in that, the rare earth hydride in step (2) and carbon material weight ratio are 1 :0.1-1:10. 5. a kind of preparation method that is applied to the rare earth hydride-carbon nano-composite material of lithium-ion battery negative electrode as claimed in claim 1, it is characterized in that, in step (2), the ball material ratio is 30:1-120:1 , ball milling time 10min-3000min. 6. a kind of preparation method that is applied to the rare earth hydride-carbon nanocomposite of lithium-ion battery negative pole as claimed in claim 1, is characterized in that, also comprises taking out and collecting rare earth hydride in the glove box that is full of argon - Carbon nanocomposite samples. 7. The rare earth hydride-carbon nanocomposite material prepared by the preparation method of a rare earth hydride-carbon nanocomposite material applied to the negative electrode of a lithium ion battery according to any one of claims 1-6.