阅读说明：本技术 嵌锂普鲁士蓝、普鲁士蓝浆料、隔膜、锂电池及制备方法 (Lithium-intercalated Prussian blue, Prussian blue slurry, diaphragm, lithium battery and preparation method ) 是由 王成豪 李正林 翁星星 陈朝晖 于 2020-12-17 设计创作，主要内容包括：本发明属于锂电池制造技术领域,具体涉及一种嵌锂普鲁士蓝、普鲁士蓝浆料、隔膜、锂电池及制备方法；其中,所述嵌锂普鲁士蓝的制备方法,包括以下步骤：锂金属电极与电源的正极相连；普鲁士蓝电极与电源的负极相连；所述锂金属电极与所述普鲁士蓝电极之间通过盐桥连接；通电,使所述锂金属电极中产生的锂离子进入到普鲁士蓝电极中的普鲁士蓝的内部形成嵌锂普鲁士蓝；将所述嵌锂普鲁士蓝涂覆于基膜的表面,制得一种具有良好电解液浸润性能的隔膜,以提高锂电池的循环使用寿命。(The invention belongs to the technical field of lithium battery manufacturing, and particularly relates to lithium-intercalated Prussian blue, Prussian blue slurry, a diaphragm, a lithium battery and a preparation method; the preparation method of the lithium-intercalated Prussian blue comprises the following steps: the lithium metal electrode is connected with the positive electrode of the power supply; the Prussian blue electrode is connected with the negative electrode of the power supply; the lithium metal electrode is connected with the Prussian blue electrode through a salt bridge; electrifying, so that lithium ions generated in the lithium metal electrode enter the Prussian blue in the Prussian blue electrode to form lithium-intercalated Prussian blue; the lithium-intercalated Prussian blue is coated on the surface of the base film to prepare the diaphragm with good electrolyte wetting performance, so that the cycle service life of the lithium battery is prolonged.)

1. The preparation method of the lithium-intercalated Prussian blue is characterized by comprising the following steps:

the lithium metal electrode is connected with the positive electrode of the power supply;

the Prussian blue electrode is connected with the negative electrode of the power supply;

the lithium metal electrode is connected with the Prussian blue electrode through a salt bridge;

and electrifying to ensure that the lithium ions generated in the lithium metal electrode enter the Prussian blue in the Prussian blue electrode to form lithium intercalation Prussian blue.

2. The method according to claim 1, wherein the reaction mixture,

the lithium metal electrode includes: a first copper reaction kettle filled with electrolyte and lithium metal.

3. The method according to claim 1, wherein the reaction mixture,

the Prussian blue electrode comprises: and a second copper reaction kettle filled with electrolyte and Prussian blue.

4. The method according to claim 1, wherein the reaction mixture,

the mass ratio of the lithium metal in the lithium metal electrode to the Prussian blue in the Prussian blue electrode is (0.001-0.1): 1.

5. a lithium-intercalating prussian blue prepared by the method of claim 1.

6. A Prussian blue slurry, which is characterized by comprising:

prussian blue and PVDF; wherein

The prussian blue is the lithium-inserted prussian blue as claimed in claim 5.

7. The Prussian blue slurry according to claim 6,

the mass ratio of the Prussian blue to the PVDF is 1 (0.05-0.1).

8. A septum, comprising:

a base film; and

prussian blue slurry coated on the surface of the base film;

the prussian blue slurry is the prussian blue slurry according to claim 6.

9. A lithium battery, comprising:

a diaphragm;

the diaphragm according to claim 8 is used as the diaphragm.

Technical Field

The invention belongs to the technical field of lithium battery manufacturing, and particularly relates to lithium-intercalated Prussian blue, Prussian blue slurry, a diaphragm, a lithium battery and a preparation method.

Background

The lithium battery has the advantages of high volumetric specific energy and mass specific energy, capability of being charged and free of pollution, and three major characteristics of the current battery industrial development, so that the lithium battery is rapidly increased in developed countries. The development of telecommunication and information markets, particularly the mass use of mobile phones and notebook computers, brings market opportunities to lithium batteries.

The diaphragm is an important component of the lithium ion battery and is positioned between the anode and the cathode in the battery, so that the lithium ions are ensured to pass through and the electron transmission is blocked. The performance of the diaphragm determines the interface structure, internal resistance and the like of the battery, directly influences the capacity, circulation, safety performance and other characteristics of the battery, and the diaphragm with excellent performance plays an important role in improving the comprehensive performance of the battery. The common diaphragm mostly adopts polypropylene and polyethylene microporous diaphragms, and the diaphragm has single performance and cannot meet the requirements of the lithium battery on service life and capacity when applied to the aspect of power batteries. Disclosure of Invention

The invention provides lithium-intercalated Prussian blue, Prussian blue slurry, a diaphragm, a lithium battery and a preparation method.

In order to solve the technical problem, the invention provides a preparation method of lithium-intercalated Prussian blue, which comprises the following steps: the lithium metal electrode is connected with the positive electrode of the power supply; the Prussian blue electrode is connected with the negative electrode of the power supply; the lithium metal electrode is connected with the Prussian blue electrode through a salt bridge; and electrifying to ensure that the lithium ions generated in the lithium metal electrode enter the Prussian blue in the Prussian blue electrode to form lithium intercalation Prussian blue.

In a second aspect, the present invention also provides a lithium-intercalating prussian blue prepared by the method as described above.

In a third aspect, the present invention also provides a prussian blue slurry, comprising: prussian blue and PVDF; wherein the Prussian blue adopts lithium intercalation Prussian blue as described above.

In a fourth aspect, the present invention also provides a separator comprising: a base film; and Prussian blue slurry coated on the surface of the base film; the prussian blue slurry is the prussian blue slurry.

In a fifth aspect, the present invention further provides a lithium battery, including: a diaphragm; the diaphragm is the diaphragm as described above.

The invention has the beneficial effects that the lithium-intercalated Prussian blue provided by the invention is coated on the surface of the base film to prepare the diaphragm with good electrolyte wetting performance; the lithium battery prepared by using the diaphragm has good cycle stability and long service life.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

In order to make the aforementioned and other objects, features and advantages of the present invention comprehensible, preferred embodiments accompanied with figures are described in detail below.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a schematic structural view of a lithium-intercalating Prussian blue of the present invention;

fig. 2 is a schematic structural view of a separator coated on one side with prussian blue slurry according to the present invention;

fig. 3 is a schematic structural view of a separator coated on both sides with prussian blue slurry according to the present invention.

In the figure:

1-prussian blue; 2-active lithium; 3-a base film.

Detailed Description

To make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is apparent that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Prussian blue is a coordination polymer with a cubic structure, and the huge open framework structure of the Prussian blue not only can accommodate transition metal ions and some small molecules, but also allows redox reaction to occur inside a channel due to the iron valence state for charge balance. These characteristics provide a tunnel and space for the transport and storage of lithium ions.

In order to prolong the service life of a lithium battery, as shown in fig. 1, the invention provides a preparation method of lithium-intercalated prussian blue, which comprises the following steps: the lithium metal electrode is connected with the positive electrode of the power supply; the Prussian blue electrode is connected with the negative electrode of the power supply; the lithium metal electrode is connected with the Prussian blue electrode through a salt bridge; and electrifying to ensure that the lithium ions generated in the lithium metal electrode enter the Prussian blue 1 in the Prussian blue electrode to form lithium-intercalated Prussian blue.

Alternatively, the salt bridge may be, but is not limited to, lithium hexafluorophosphate.

Specifically, a lithium metal electrode is connected with the positive electrode of a power supply, and a Prussian blue electrode is connected with the negative electrode of the power supply; the lithium metal electrode is connected with the Prussian blue electrode through a salt bridge; after electrifying, enabling lithium ions generated in the lithium metal electrode to enter the Prussian blue electrode to be combined with electrons in the Prussian blue 1 to obtain active lithium 2, and forming lithium-intercalated Prussian blue; after the reaction is finished, cleaning the surface of the lithium-intercalated Prussian blue under a vacuum condition; and baking and drying the washed lithium-intercalated Prussian blue, and then carrying out vacuum packaging.

Wherein, optionally, the lithium metal electrode comprises: a first copper reaction kettle filled with electrolyte and lithium metal.

Optionally, the prussian blue electrode includes: and a second copper reaction kettle filled with electrolyte and Prussian blue.

Alternatively, the electrolyte may be, but is not limited to, lithium hexafluorophosphate; the particle size distribution D50 of the Prussian blue can be but is not limited to 0.2-2.0 μm.

Specifically, lithium metal is placed into a first copper reaction kettle, lithium hexafluorophosphate is filled into the first copper reaction kettle, and the first copper reaction kettle is vacuumized to obtain a lithium metal electrode; and putting the Prussian blue into a second copper reaction kettle, filling lithium hexafluorophosphate into the second copper reaction kettle, and vacuumizing the second copper reaction kettle to obtain the Prussian blue electrode.

Optionally, the mass ratio of the lithium metal in the lithium metal electrode to the prussian blue in the prussian blue electrode may be, but is not limited to (0.001-0.1): 1.

further, the invention also provides the lithium-intercalated Prussian blue prepared by the method.

Further, the invention also provides a prussian blue slurry, which comprises the following components: prussian blue and PVDF; wherein the Prussian blue adopts lithium intercalation Prussian blue as described above.

Optionally, the mass ratio of the Prussian blue to the PVDF is not limited to 1 (0.05-0.1).

Further, the present invention also provides a separator comprising: a base film 3; and Prussian blue slurry coated on the surface of the base film 3; the prussian blue slurry is the prussian blue slurry.

The base film 3 may be, but is not limited to: PE, PP, PI or PET.

Further, the present invention also provides a lithium battery, including: a diaphragm; the diaphragm is the diaphragm as described above.

Example 1

Putting 100kg of lithium metal into a first copper reaction kettle, filling 50kg of lithium hexafluorophosphate into the first copper reaction kettle, and vacuumizing the first copper reaction kettle to obtain a lithium metal electrode; 500kg of Prussian blue with the particle size distribution D50 of 1.5 mu m is placed in a second copper reaction kettle, 300kg of lithium hexafluorophosphate is filled in the second copper reaction kettle, and the second copper reaction kettle is vacuumized to prepare a Prussian blue electrode; the bottoms of the first copper reaction kettle and the second copper reaction kettle are connected through a lithium hexafluorophosphate bridge.

Connecting the lithium metal electrode with the positive electrode of a power supply, and connecting the Prussian blue electrode with the negative electrode of the power supply; after electrifying, enabling lithium ions to enter the Prussian blue to form lithium-intercalated Prussian blue; after the reaction is finished, filling dry nitrogen into the second copper reaction kettle, and discharging lithium hexafluorophosphate; carrying out secondary vacuum pumping on the second copper reaction kettle, and filling DMC solvent into the second copper reaction kettle to clean the surface of the lithium-intercalated Prussian blue; and baking and drying the washed lithium-intercalated Prussian blue, and then carrying out vacuum packaging on the dried lithium-intercalated Prussian blue.

Example 2

Putting 0.5kg of lithium metal into a first copper reaction kettle, filling 30kg of lithium hexafluorophosphate into the first copper reaction kettle, and vacuumizing the first copper reaction kettle to obtain a lithium metal electrode; 500kg of Prussian blue with the particle size distribution D50 of 0.2 mu m is placed in a second copper reaction kettle, 200kg of lithium hexafluorophosphate is charged into the second copper reaction kettle, and the second copper reaction kettle is vacuumized to prepare a Prussian blue electrode; the bottoms of the first copper reaction kettle and the second copper reaction kettle are connected through a lithium hexafluorophosphate bridge.

Connecting the lithium metal electrode with the positive electrode of a power supply, and connecting the Prussian blue electrode with the negative electrode of the power supply; after electrifying, enabling lithium ions to enter the Prussian blue to form lithium-intercalated Prussian blue; after the reaction is finished, filling dry nitrogen into the second copper reaction kettle, and discharging lithium hexafluorophosphate; carrying out secondary vacuum pumping on the second copper reaction kettle, and filling DMC solvent into the second copper reaction kettle to clean the surface of the lithium-intercalated Prussian blue; and baking and drying the washed lithium-intercalated Prussian blue, and then carrying out vacuum packaging on the dried lithium-intercalated Prussian blue.

Example 3

Putting 50kg of lithium metal into a first copper reaction kettle, filling 80kg of lithium hexafluorophosphate into the first copper reaction kettle, and vacuumizing the first copper reaction kettle to obtain a lithium metal electrode; 500kg of Prussian blue with the particle size distribution D50 of 2.0 mu m is placed in a second copper reaction kettle, 100kg of lithium hexafluorophosphate is filled in the second copper reaction kettle, and the second copper reaction kettle is vacuumized to prepare a Prussian blue electrode; the bottoms of the first copper reaction kettle and the second copper reaction kettle are connected through a lithium hexafluorophosphate bridge.

Connecting the lithium metal electrode with the positive electrode of a power supply, and connecting the Prussian blue electrode with the negative electrode of the power supply; after electrifying, enabling lithium ions to enter the Prussian blue to form lithium-intercalated Prussian blue; after the reaction is finished, filling dry nitrogen into the second copper reaction kettle, and discharging lithium hexafluorophosphate; carrying out secondary vacuum pumping on the second copper reaction kettle, and filling DMC solvent into the second copper reaction kettle to clean the surface of the lithium-intercalated Prussian blue; and baking and drying the washed lithium-intercalated Prussian blue, and then carrying out vacuum packaging on the dried lithium-intercalated Prussian blue.

Example 4

Putting 30kg of lithium metal into a first copper reaction kettle, filling 100kg of lithium hexafluorophosphate into the first copper reaction kettle, and vacuumizing the first copper reaction kettle to obtain a lithium metal electrode; 500kg of Prussian blue with the particle size distribution D50 of 1.8 mu m is placed in a second copper reaction kettle, 150kg of lithium hexafluorophosphate is filled in the second copper reaction kettle, and the second copper reaction kettle is vacuumized to prepare a Prussian blue electrode; the bottoms of the first copper reaction kettle and the second copper reaction kettle are connected through a lithium hexafluorophosphate bridge.

Connecting the lithium metal electrode with the positive electrode of a power supply, and connecting the Prussian blue electrode with the negative electrode of the power supply; after electrifying, enabling lithium ions to enter the Prussian blue to form lithium-intercalated Prussian blue; after the reaction is finished, filling dry nitrogen into the second copper reaction kettle, and discharging lithium hexafluorophosphate; carrying out secondary vacuum pumping on the second copper reaction kettle, and filling DMC solvent into the second copper reaction kettle to clean the surface of the lithium-intercalated Prussian blue; and baking and drying the washed lithium-intercalated Prussian blue, and then carrying out vacuum packaging on the dried lithium-intercalated Prussian blue.

Example 5

200kg of lithium-intercalated Prussian blue from example 1 was added to 160kg of a PVDF solution having a solid content of 10% to prepare Prussian blue slurry.

And coating the Prussian blue slurry on the surface of a PE film with the thickness of 12 mu m, wherein the thickness of the coating is 4 mu m, and then drying and rolling the coating through an oven.

Example 6

160kg of lithium-intercalated Prussian blue from example 2 was added to 160kg of a PVDF solution having a solid content of 10% to prepare Prussian blue slurry.

And coating the Prussian blue slurry on the surface of a PE film with the thickness of 16 mu m, wherein the thickness of the coating is 3 mu m, and then drying and rolling the coating through an oven.

Example 7

320kg of lithium-intercalated Prussian blue from example 3 was added to 160kg of a PVDF solution having a solids content of 10% to prepare Prussian blue slurry.

And coating the Prussian blue slurry on the surface of a PE film with the thickness of 10 mu m, wherein the thickness of the coating is 4 mu m, and then drying and rolling the coating through an oven.

Example 8

280kg of lithium-intercalated Prussian blue from example 4 was added to 160kg of a PVDF solution having a solids content of 10% to prepare Prussian blue slurry.

And coating the Prussian blue slurry on the surface of a PE film with the thickness of 12 microns, wherein the thickness of the coating is 2 microns, and then drying and rolling the coating through an oven.

Example 9

Homogenizing, coating, rolling and die-cutting lithium iron phosphate to obtain a positive pole piece;

homogenizing, coating, rolling and die-cutting graphite to obtain a negative pole piece;

assembling the positive pole piece and the negative pole piece with the diaphragm prepared in the embodiment 5 in a lamination mode to prepare the lithium ion battery;

baking the assembled lithium ion battery, injecting lithium hexafluorophosphate electrolyte, packaging and aging;

and carrying out formation charging, secondary packaging, aging and capacity grading on the aged lithium ion battery.

Example 10

Homogenizing, coating, rolling and die-cutting lithium iron phosphate to obtain a positive pole piece;

homogenizing, coating, rolling and die-cutting graphite to obtain a negative pole piece;

assembling the positive pole piece and the negative pole piece with the diaphragm prepared in the embodiment 6 in a lamination mode to prepare the lithium ion battery;

baking the assembled lithium ion battery, injecting lithium hexafluorophosphate electrolyte, packaging and aging;

and carrying out formation charging, secondary packaging, aging and capacity grading on the aged lithium ion battery.

Example 11

Homogenizing, coating, rolling and die-cutting lithium iron phosphate to obtain a positive pole piece;

homogenizing, coating, rolling and die-cutting graphite to obtain a negative pole piece;

assembling the positive pole piece and the negative pole piece with the diaphragm prepared in the embodiment 7 in a lamination mode to prepare the lithium ion battery;

baking the assembled lithium ion battery, injecting lithium hexafluorophosphate electrolyte, packaging and aging;

and carrying out formation charging, secondary packaging, aging and capacity grading on the aged lithium ion battery.

Example 12

Homogenizing, coating, rolling and die-cutting lithium iron phosphate to obtain a positive pole piece;

homogenizing, coating, rolling and die-cutting graphite to obtain a negative pole piece;

assembling the positive pole piece and the negative pole piece with the diaphragm prepared in the embodiment 8 in a lamination mode to prepare the lithium ion battery;

baking the assembled lithium ion battery, injecting lithium hexafluorophosphate electrolyte, packaging and aging;

and carrying out formation charging, secondary packaging, aging and capacity grading on the aged lithium ion battery.

Comparative example 1

200kg of Prussian blue containing no lithium was added to 160kg of a PVDF solution having a solid content of 10% to prepare Prussian blue slurry.

And coating the Prussian blue slurry on the surface of a PE film with the thickness of 12 mu m, and then drying and rolling the PE film through an oven.

Comparative example 2

Homogenizing, coating, rolling and die-cutting lithium iron phosphate to obtain a positive pole piece;

homogenizing, coating, rolling and die-cutting graphite to obtain a negative pole piece;

assembling the positive pole piece, the negative pole piece and the diaphragm prepared in the comparative example 1 in a lamination mode to prepare the lithium ion battery;

baking the assembled lithium ion battery, injecting lithium hexafluorophosphate electrolyte, packaging and aging;

and carrying out formation charging, secondary packaging, aging and capacity grading on the aged lithium ion battery.

Comparative analysis of performance parameters

The relevant properties of the separators prepared in examples 5 to 8 and comparative example 1 were tested in this section, and the results are shown in table 1.

Table 1 summary of performance test results for membranes

As can be seen from the data in table 1, the tensile strength and elongation of the separators prepared in examples 5 to 8 are higher than those of the separator prepared in comparative example 1, and as can be seen from the contact angle data of the separators prepared in examples 5 to 8, the present invention prepared a hydrophobic and oleophilic separator, which improved the electrophilic electrolyte performance of the separator.

The relevant performance of the lithium batteries prepared in examples 9 to 12 and comparative example 2 was tested in this section, and the results are shown in table 2.

TABLE 2 summary of performance test results for lithium batteries

It can be seen from the data in table 2 that the lithium batteries manufactured in examples 9 to 12 have greatly improved battery capacity, cycle stability, and battery life, compared to the lithium battery in comparative example 2.

In conclusion, the lithium-intercalated Prussian blue is coated on the surface of the base film to prepare the diaphragm with good electrolyte wetting performance; the lithium battery prepared by using the diaphragm has good cycle stability and long service life.

In light of the foregoing description of the preferred embodiment of the present invention, many modifications and variations will be apparent to those skilled in the art without departing from the spirit and scope of the invention. The technical scope of the present invention is not limited to the content of the specification, and must be determined according to the scope of the claims.