WO2023108661A1 - Non-aqueous electrolyte and lithium ion secondary battery - Google Patents

Abstract

Disclosed in the present invention are a lithium ion secondary battery and a non-aqueous electrolyte thereof. The non-aqueous electrolyte comprises an electrolyte solution and an additive dispersed in the electrolyte solution. The additive comprises one or more of polyacrylonitrile or solid particles coated with polyacrylonitrile, polytetrafluoroethylene or solid particles coated with polytetrafluoroethylene, polyvinylidene fluoride or solid particles coated with polyvinylidene fluoride, and a copolymer or solid particles coated with a copolymer. The copolymer is a copolymer comprising at least one of polyacrylonitrile, polytetrafluoroethylene or polyvinylidene fluoride. The cycling life and the storage performance of a lithium ion secondary battery can be improved, and the safety performance of a lithium ion secondary battery can be greatly improved.

Description

Non-aqueous electrolyte and lithium-ion secondary battery technical field

The invention relates to the field of energy storage devices, in particular to a lithium-ion secondary battery and its non-aqueous electrolyte.

Background technique

Lithium-ion power batteries have outstanding advantages such as high energy density, high working voltage, and environmental friendliness, and have broad application prospects in the fields of large electric tools, electric vehicles, and grid energy storage. As the energy density of lithium-ion batteries increases, ternary NCM materials with high nickel content are usually used to increase the capacity of the battery. However, a high content of nickel has high reactivity at high temperature, especially the side reaction with the electrolyte is intensified under high temperature conditions, which greatly reduces the high temperature cycle life and high temperature storage performance of the battery; at the same time, the high reactivity of high nickel NCM materials also greatly increase the safety hazard of batteries at high temperatures. In recent years, reports of fires and even explosions caused by lithium batteries have become common, and the safety of batteries has attracted widespread attention. In addition, safety issues are also a bottleneck restricting the development of large-scale and high-energy lithium-ion batteries.

Therefore, many studies have attempted to improve the safety performance of batteries. For example, a non-flammable electrolyte can reduce the flammability of the electrolyte and prevent explosions, but it is not easy to use a non-flammable electrolyte on a large-sized power battery to prevent explosions; in addition, increasing the non-flammability of the electrolyte usually reduces other components of the cell. performance. Another method is to use a coated separator, but the effect is not ideal, because the commonly used polyethylene separator is unstable at high temperatures, shrinks, and easily causes internal short circuits.

technical problem

Therefore, it is necessary to provide a lithium-ion secondary battery with long cycle life and high safety performance to overcome the above defects.

technical solution

The object of the present invention is to provide a non-aqueous electrolytic solution, and the lithium-ion secondary battery prepared by the non-aqueous electrolytic solution has a long cycle life and high safety performance.

Another object of the present invention is to provide a lithium ion secondary battery, which has a long cycle life and high safety performance.

To achieve the above object, the present invention provides a non-aqueous electrolytic solution, the non-aqueous electrolytic solution comprises: an electrolytic solution, and an additive, the additive comprises polyacrylonitrile or solid particles coated with polyacrylonitrile, polyacrylonitrile One of tetrafluoroethylene or solid particles coated with polytetrafluoroethylene, polyvinylidene fluoride or solid particles coated with polyvinylidene fluoride, and copolymers or solid particles coated with copolymers or Various, wherein the copolymer is a copolymer comprising at least one of polyacrylonitrile, polytetrafluoroethylene or polyvinylidene fluoride.

In a practicable manner, the additive is a solid particle with a core-shell structure, and the shell of the additive is polyacrylonitrile, polytetrafluoroethylene, polyvinylidene fluoride or a copolymer thereof coated on the core , the core of the additive is an inorganic particle or a polymer particle.

The coating of the present invention may be full coating or partial coating.

In a practicable manner, the additive is a solid particle with a core-shell structure, and the solid particle may include one or more cores.

In an achievable manner, the inorganic particles are red phosphorus, aluminum oxide, aluminum hydroxide, zeolite, phosphorus pentoxide, titanium dioxide, calcium carbonate, calcium hydroxide, calcium sulfate, sodium hydroxide, sodium carbonate, Sodium sulfate, magnesium hydroxide, magnesium sulfate, magnesium carbonate or silica particles. Many solid inorganic particles do not have good compatibility and electrochemical stability with electrolyte solutions. The outer surface of the solid inorganic particle is covered by polyacrylonitrile, polytetrafluoroethylene or polyvinylidene fluoride coating, which can improve the compatibility and stability of the inorganic particle. The coated inorganic particles have the same effectiveness as polyacrylonitrile, polytetrafluoroethylene or polyvinylidene fluoride, and can improve the cycle life and safety performance of lithium-ion secondary batteries. The particle size of the inorganic particles is 0.01- 20um, or 0.1-10um.

In a practicable manner, the polymer particles are polyethylene, polystyrene, polymethyl methacrylate, polyethylene terephthalate, polyvinyl chloride, polyacrylamide, polyethylene oxide or Polypropylene particles. Polyethylene, polystyrene, polymethyl methacrylate, polyethylene terephthalate, polyvinyl chloride, polyacrylamide, polyethylene oxide, or polypropylene do not have good electrochemical stability. In addition, polyethylene , polystyrene, polymethyl methacrylate, polyethylene oxide or polypropylene particles have a lower density than the electrolyte solution, so they will float in the electrolyte solution. Therefore, they cannot be used as excellent solid additives for electrolytes of lithium-ion secondary batteries. Polyethylene or polypropylene coated with polyacrylonitrile, polytetrafluoroethylene or polyvinylidene fluoride increases particle density and improves electrochemical performance. Coated polyethylene, polystyrene, polymethyl methacrylate, polyethylene terephthalate, polyvinyl chloride, polyacrylamide, polyethylene oxide, or polypropylene particles can be used as good lithium ion secondary Secondary battery electrolyte solid additive. The particle size of the polymer particles is 0.05-25um, or 0.5-15um, or 1-10um.

In an achievable manner, the mass content ratio of the shell of the additive is 0.1%-99.9%, or 10%-95%.

In a practicable manner, the additives are polyacrylonitrile solid particles, polytetrafluoroethylene solid particles, polyvinylidene fluoride solid particles, and polymers (polyacrylonitrile, polytetrafluoroethylene or polyvinylidene One or more of solid particles formed from copolymers of vinylidene fluoride).

In an achievable manner, the additive is a solid particle with an average particle diameter of 0.1-30 microns, or 1-10 microns. Usually, the particle size of the additive is 0.1-30um. When the particle size is greater than 30 microns, it is easy to settle in the electrolyte solution, and it will cause the injection head to be blocked when the electrolyte is injected; when the particle size is less than 0.1 microns, it will easily cause the diaphragm hole to be blocked. In order to obtain a uniform and stable non-aqueous electrolyte, in some embodiments, the additive can obtain the required particle size through high-energy ball milling, and then the moisture contained in the additive can be further reduced by vacuum drying, etc., so that the additive Moisture is reduced to below 50ppm.

In an achievable manner, the mass proportion of the additive in the electrolyte is 0.1%-30%, or 1%-20%, or 3%-20%. When it is lower than 0.1%, the performance of the lithium-ion secondary battery is not significantly improved, and if it is higher than 30%, the viscosity of the non-aqueous electrolyte will increase, thereby increasing the impedance of the battery and deteriorating the cycle performance.

Typically, the electrolyte solution includes a non-aqueous solvent and a lithium salt. Non-aqueous solvents include dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), ethylene carbonate (EC), propylene carbonate (PC), methyl propyl carbonate (MPC), One or more of γ-butyrolactone (GBL), ethyl acetate (EA) and ethyl propionate (EP). In some embodiments, the electrolyte solution may also include a second additive, and the second additive mainly includes film-forming additives, conductive additives, flame retardant additives, overcharge protection additives, additives for improving low-temperature performance, and multifunctional additives.

The present invention also provides a lithium ion secondary battery, the lithium ion secondary battery includes the above-mentioned non-aqueous electrolytic solution.

Beneficial effect

Compared with the prior art, the present invention provides a lithium ion secondary battery and its non-aqueous electrolyte, the non-aqueous electrolyte includes an electrolyte solution and additives dispersed in the electrolyte solution, the additives include poly Acrylonitrile or polyacrylonitrile coated solid particles, polytetrafluoroethylene or polytetrafluoroethylene coated solid particles, polyvinylidene fluoride or polyvinylidene fluoride coated solid particles, and copolymers Or one or more of the solid particles coated with a copolymer, wherein the copolymer is a copolymer formed by one or more of polyacrylonitrile, polytetrafluoroethylene and polyvinylidene fluoride. The additive is insoluble in the electrolyte, has good chemical compatibility with the electrolyte solution, and has excellent electrochemical stability in lithium-ion secondary batteries. These additives dispersed in the lithium battery cell can fill the gap at the edge of the separator, and protect the edge side of the electrode, current collector or tab from or reduce the electrochemical reaction with the electrolyte. They can improve the cycle life and storage performance of lithium-ion secondary batteries. When the lithium-ion secondary battery components are deformed and the diaphragm is broken, the dispersed solid additives can prevent the short circuit between the positive and negative electrodes, which can greatly improve the safety performance of the lithium-ion secondary battery.

Description of drawings

FIG. 1 is a schematic diagram of the internal structure of a lithium-ion secondary battery.

BEST MODE FOR CARRYING OUT THE INVENTION

"Ranges" are disclosed herein in terms of lower limits and upper limits. There can be one or more lower bounds, and one or more upper bounds, respectively. A given range is defined by selecting a lower limit and an upper limit. Selected lower and upper limits define the boundaries of a particular range. All ranges that may be defined in this manner are inclusive and combinable, ie, any lower limit may be combined with any upper limit to form a range. For example, ranges of 60-120 and 80-110 are listed for a particular parameter, with the understanding that ranges of 60-110 and 80-120 are contemplated. Additionally, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4, and 5 are listed, the following ranges are all expected: 1-3, 1-4, 1-5, 2- 3, 2-4 and 2-5. In the present invention, unless otherwise specified, all the embodiments and preferred embodiments mentioned herein can be combined with each other to form new technical solutions.

In the present invention, if there is no special description, all the technical features and preferred features mentioned herein can be combined with each other to form a new technical solution. In the present invention, unless otherwise specified, all the steps mentioned herein can be performed sequentially or randomly, but are preferably performed sequentially.

Example 1

(1) Preparation of non-aqueous electrolyte

In an argon-filled glove box (oxygen content <1ppm, water content <1ppm), mix 59.9 g of ethyl methyl carbonate (EMC) with 26.6 g of ethylene carbonate (EC), and continue to add 13.5 g of g lithium hexafluorophosphate, and 1 g vinylene carbonate (VC) were stirred and dissolved to obtain an electrolyte solution, which was cooled to room temperature for later use. Add additive A to the above electrolyte solution by 5% by mass, stir at high speed for 10 minutes, take it out of the glove box after sealing, perform ultrasonic treatment (frequency 50Hz), control the temperature of the water bath at 25°C, and put it into the glove box after sealing spare.

(2) Preparation of dry cells

Positive electrode material: in parts by mass, active material LiNi _0.8 Co _0.1 Mn _0.1 O ₂ 95%, binder 2%, conductive carbon black 2%, VGCF 1%, with aluminum foil as current collector; negative electrode material: active material is Artificial graphite, CMC 2%, SBR 1%, SP 1%, VGCF 1%, use copper foil as current collector; use PE separator, make lithium-ion secondary battery dry cell through coating and lamination process.

(3) Preparation of lithium-ion secondary battery

Transfer the dried lithium-ion secondary battery dry cell into a glove box filled with argon, inject 40g of the above-mentioned non-aqueous electrolyte into the lithium-ion secondary battery dry cell with a needle tube, seal it, take it out and let it stand After 24 hours, after subsequent pre-charging, final sealing, formation, and capacity separation, the lithium-ion secondary battery was obtained. The capacity of the lithium-ion secondary battery was 10Ah, and the energy density was about 250 Wh/kg. The battery is tested for battery performance.

The present invention does not limit the structure of the lithium-ion secondary battery, which may be cylindrical, square or button-shaped, soft-packed or steel-cased or aluminum-cased. It is worth noting that this embodiment prepares dry cells by stacking sheets. Of course, in other embodiments, dry cells can also be prepared by winding, and dry cells can also be prepared into different shapes. Such as square, cylindrical or elliptical, that is, conventional manufacturing methods for lithium-ion secondary batteries can be applied to the present invention, which is not limited here.

Battery performance test method:

(1) Battery life test conditions: at an ambient temperature of 45 °C, the above-mentioned lithium-ion secondary battery was tested at 2.70 V to 4.25 Charge and discharge in the V voltage range, and the charge and discharge rate is 1C. The charge and discharge cycle stability under high temperature conditions is investigated.

(2) Acupuncture test conditions: charge at room temperature at 1C to 4.25V, continue charging at constant voltage, cut-off current 0.05C, needle diameter 5mm, speed 25mm/sec, needle vertically penetrate lithium-ion secondary battery, observe the lithium-ion secondary battery Check whether the secondary battery catches fire or explodes during this process.

Example 2

Add 1% additive A to the basic electrolyte, and prepare the electrolyte by ultrasonic. The preparation and performance testing of the lithium-ion secondary battery are the same as in Example 1.

Example 3

Add 3% additive A to the basic electrolyte, and prepare the electrolyte by ultrasonic. The preparation and performance testing of the lithium-ion secondary battery are the same as in Example 1.

Example 4

Add 5% additive B to the basic electrolyte, and prepare the electrolyte by ultrasonic. The preparation and performance testing of the lithium-ion secondary battery are the same as in Example 1.

Example 5

5% additive C was added to the basic electrolyte, and the electrolyte was prepared by ultrasonic. The preparation and performance testing of the lithium-ion secondary battery are the same as in Example 1.

Example 6

Add 5% additive D to the basic electrolyte, and prepare the electrolyte by ultrasonic. The preparation and performance testing of the lithium-ion secondary battery are the same as in Example 1.

Example 7

Add 5% additive E to the basic electrolyte, and prepare the electrolyte by ultrasonic. The preparation and performance testing of the lithium-ion secondary battery are the same as in Example 1.

Example 8

Add 5% additive F to the basic electrolyte, and prepare the electrolyte by ultrasonic. The preparation and performance testing of the lithium-ion secondary battery are the same as in Example 1.

Example 9

Add 5% additive G to the basic electrolyte, and prepare the electrolyte by ultrasonic. The preparation and performance testing of the lithium-ion secondary battery are the same as in Example 1.

Example 10

5% additive H was added to the basic electrolyte, and the electrolyte was prepared by ultrasonication. The preparation and performance testing of the lithium-ion secondary battery are the same as in Example 1.

Example 11

Add 5% additive I to the basic electrolyte, and prepare the electrolyte by ultrasonic. The preparation and performance testing of the lithium-ion secondary battery are the same as in Example 1.

Example 12

Add 5% additive J to the basic electrolyte, and prepare the electrolyte by ultrasonic. The preparation and performance testing of the lithium-ion secondary battery are the same as in Example 1.

Example 13

Add 5% additive K to the basic electrolyte, and prepare the electrolyte by ultrasonic. The preparation and performance testing of the lithium-ion secondary battery are the same as in Example 1.

Example 14

Add 5% additive L to the basic electrolyte, and prepare the electrolyte by ultrasonic. The preparation and performance testing of the lithium-ion secondary battery are the same as in Example 1.

Example 15

Add 5% additive M to the basic electrolyte, and prepare the electrolyte by ultrasonic. The preparation and performance testing of the lithium-ion secondary battery are the same as in Example 1.

Example 16

Adding 5% additive N to the basic electrolyte, the electrolyte was prepared by ultrasonic. The preparation and performance testing of the lithium-ion secondary battery are the same as in Example 1.

Example 17

Adding 5% additive O to the basic electrolyte, the electrolyte was prepared by ultrasonic. The preparation and performance testing of the lithium-ion secondary battery are the same as in Example 1.

Example 18

Add 5% additive P to the basic electrolyte, and prepare the electrolyte by ultrasonic. The preparation and performance testing of the lithium-ion secondary battery are the same as in Example 1.

Example 19

5% additive Q was added to the basic electrolyte, and the electrolyte was prepared by ultrasonic. The preparation and performance testing of the lithium-ion secondary battery are the same as in Example 1.

Example 20

5% additive R was added to the basic electrolyte, and the electrolyte was prepared by ultrasonic. The preparation and performance testing of the lithium-ion secondary battery are the same as in Example 1.

Example 21

Add 5% additive S to the basic electrolyte, and prepare the electrolyte by ultrasonic. The preparation and performance testing of the lithium-ion secondary battery are the same as in Example 1.

Example 22

5% additive T was added to the basic electrolyte, and the electrolyte was prepared by ultrasonic. The preparation and performance testing of the lithium-ion secondary battery are the same as in Example 1.

Example 23

5% additive U was added to the basic electrolyte, and the electrolyte was prepared by ultrasonic. The preparation and performance testing of the lithium-ion secondary battery are the same as in Example 1.

Comparative example 1

The same method as in Example 1 was used to obtain the basic electrolyte as a comparison, without adding solid additives.

Comparative example 2

Add 5% additive V to the basic electrolyte, and prepare the electrolyte by ultrasonic. The preparation and performance testing of the lithium-ion secondary battery are the same as in Example 1.

Comparative example 3

Adding 5% additive W to the basic electrolyte, the electrolyte was prepared by ultrasonic. The preparation and performance testing of the lithium-ion secondary battery are the same as in Example 1.

Comparative example 4

Add 5% additive X to the basic electrolyte, and prepare the electrolyte by ultrasonic. The preparation and performance testing of the lithium-ion secondary battery are the same as in Example 1.

The description of additives in each embodiment and comparative example is shown in Table 1.

Table 1 Additives in each embodiment and comparative example

Additive name	additive material	Average particle size (μm)	Coating material content (%)
A	Polyacrylonitrile	6.2	-
B	PTFE	2.1	-
C	polyvinylidene fluoride	6.0	-
D.	Polytetrafluoroethylene coated with polyacrylonitrile	8.4	33
E.	Aluminum oxide coated with polyacrylonitrile	4.2	33
f	Aluminum hydroxide coated with polyacrylonitrile	4.6	33
G	Silica coated with polyacrylonitrile	3.8	33
h	red phosphorus coated with polyacrylonitrile	6.9	33
I	Zeolite coated with polyacrylonitrile	7.0	33
J	Polyacrylonitrile coated with PTFE	8.9	33
K	Aluminum oxide coated with PTFE	4.5	33
L	Aluminum hydroxide coated with PTFE	4.4	33
m	Silica coated with PTFE	3.2	33
N	Red Phosphorus coated with Teflon	6.1	33
o	PTFE-coated polyethylene	10.3	50
P	PTFE-coated polypropylene	12.2	50
Q	Zeolite coated with PTFE	7.9	33
R	Alumina coated with polyvinylidene fluoride	3.8	33
S	Silicon dioxide coated with polyvinylidene fluoride	5.0	33
T	polyvinylidene fluoride coated polyethylene	10.2	60
u	polyvinylidene fluoride coated polypropylene	12.1	60
V	Aluminum oxide	1.6	-
W	Red phosphorus	6.1	-
x	polyethylene	8.2	-

See Table 2 for a comparison of the cycle performance and storage performance of the lithium-ion secondary batteries of Examples 1-23 and Comparative Examples 1-4 at high temperatures.

Table 2 Comparison of high temperature cycle and storage performance

the	Initial capacity (Ah)	55 ℃ 300 cycle capacity retention (%)	Capacity retention (%)	Capacity recovery (%)
Example 1	10.10	93.8	91.2	97.3
Example 2	10.11	91.1	82.3	93.8
Example 3	10.12	93.5	90.0	96.2
Example 4	10.09	94.4	93.0	98.2
Example 5	10.11	93.8	92.4	97.6
Example 6	10.10	93.6	91.0	97.5
Example 7	10.11	93.5	90.8	97.0
Example 8	10.13	93.4	91.1	97.5
Example 9	10.14	93.5	91.5	97.6
Example 10	10.12	93.2	91.2	97.2
Example 11	10.13	93.1	91.2	97.1
Example 12	10.13	94.1	93.0	98.2
Example 13	10.12	94.4	93.1	98.1
Example 14	10.11	94.2	93.4	98.6
Example 15	10.11	94.2	93.4	98.3
Example 16	10.11	94.3	93.5	98.2
Example 17	10.12	94.5	93.3	98.5
Example 18	10.09	94.2	93.0	98.3
Example 19	10.08	93.9	93.2	98.6
Example 20	10.09	93.8	92.3	97.8
Example 21	10.10	94.0	92.8	98.0
Example 22	10.11	93.2	92.5	97.7
Example 23	10.12	93.6	92.7	98.0
Comparative example 1	10.16	87.6	78.5	89.2
Comparative example 2	10.13	88.1	75.3	90.4
Comparative example 3	10.12	86.5	77.2	89.1
Comparative example 4	10.12	87.3	78.3	89.0

It can be seen from Table 2 that compared with Comparative Examples 1-4, the lithium-ion secondary batteries of Examples 1-23 added the additive of the present invention, and their high-temperature cycle performance and storage performance have been significantly improved. Although Comparative Examples 2-4 An additive of solid particles is also added, but the chemical compatibility and electrochemical stability of the additive cannot meet the requirements, and there is no improvement in the high-temperature cycle performance and storage performance of the lithium-ion secondary battery. Table 3 shows the performance results of the acupuncture test of the lithium-ion secondary batteries of the various examples and comparative examples. Table 3 Comparison of acupuncture test performance of lithium-ion secondary batteries

the	Acupuncture Test Results
Example 1	No fire or explosion
Example 2	fire and explosion
Example 3	No fire or explosion
Example 4	No fire or explosion
Example 5	No fire or explosion
Example 6	No fire or explosion
Example 7	No fire or explosion
Example 8	No fire or explosion
Example 9	No fire or explosion
Example 10	No fire or explosion
Example 11	No fire or explosion
Example 12	No fire or explosion
Example 13	No fire or explosion
Example 14	No fire or explosion
Example 15	No fire or explosion
Example 16	No fire or explosion
Example 17	No fire or explosion
Example 18	No fire or explosion
Example 19	No fire or explosion
Example 20	No fire or explosion
Example 21	No fire or explosion
Example 22	No fire or explosion
Example 23	No fire or explosion
Comparative example 1	fire and explosion
Comparative example 2	fire and explosion
Comparative example 3	fire and explosion
Comparative example 4	fire and explosion

From Comparative Example 1 and Examples 1, 3-23, it can be seen that the additive of the present invention has a significant improvement effect on the safety performance of lithium-ion secondary batteries.

From Example 2 in Table 3, it can be seen that when the content of the additive is low, the safety performance of the lithium-ion secondary battery is not significantly improved, but it can be seen from Table 2 that the high-temperature cycle performance and storage performance of Example 2 are significantly improved. , it can be seen that the content control of additives is very important, and the optimal mass proportion of additives is 3%~20%.

As shown in Figure 1, the present invention provides a kind of lithium ion secondary battery and its non-aqueous electrolytic solution, and non-aqueous electrolytic solution comprises electrolyte solution and the additive 6 that is dispersed in described electrolytic solution, and described additive 6 comprises Polyacrylonitrile or polyacrylonitrile coated solid particles, polytetrafluoroethylene or polytetrafluoroethylene coated solid particles, and polyvinylidene fluoride or polyvinylidene fluoride coated solid particles one or more. Additive 6 is insoluble in the electrolyte, has good chemical compatibility with the electrolyte solution, and has excellent electrochemical stability in lithium-ion secondary batteries. These additives 6 are dispersed in the lithium-ion secondary battery to fill the gaps at the edge of the separator 2 and protect the edges of the electrodes, current collectors, positive tabs 4 and negative tabs 5 from electrochemically reacting with the electrolyte. They can improve the cycle life and storage performance of lithium-ion secondary batteries. When the lithium-ion secondary battery components are deformed and the diaphragm 2 is broken, the dispersed solid additive 6 can prevent the short circuit between the positive electrode 3 and the negative electrode 1, which can greatly improve the safety performance of the battery cell.

What is disclosed above is only a preferred embodiment of the present invention, and of course it cannot limit the scope of rights of the present invention. Therefore, equivalent changes made according to the patent scope of the present invention still fall within the scope of the present invention.

Claims (10)

1. A non-aqueous electrolytic solution for a lithium-ion secondary battery, characterized in that the non-aqueous electrolytic solution includes an electrolytic solution and additives, and the additives include polyacrylonitrile or solid particles coated with polyacrylonitrile, polytetrafluoroethylene One or more of vinyl fluoride or solid particles coated with polytetrafluoroethylene, polyvinylidene fluoride or solid particles coated with polyvinylidene fluoride, and copolymers or solid particles coated with copolymers , wherein the copolymer is a copolymer comprising at least one of polyacrylonitrile, polytetrafluoroethylene or polyvinylidene fluoride. .
2. The non-aqueous electrolytic solution according to claim 1, wherein the additive is a solid particle with a core-shell structure, and the shell of the additive is polyacrylonitrile, polytetrafluoroethylene, polyvinylidene coated on the core. Vinyl difluoride or its copolymer, the core of the additive is an inorganic particle or a polymer particle.
3. The non-aqueous electrolytic solution according to claim 2, wherein the inorganic particles are red phosphorus, Aluminum oxide, aluminum hydroxide, zeolite, phosphorus pentoxide, titanium dioxide, calcium carbonate, calcium hydroxide, calcium sulfate, sodium hydroxide, sodium carbonate, sodium sulfate, magnesium hydroxide, magnesium sulfate, magnesium carbonate or silica particles , the particle size of the inorganic particles is 0.01-20um.
4. The non-aqueous electrolytic solution according to claim 2, wherein the polymer particles are polyethylene, polystyrene, polymethyl methacrylate, polyethylene terephthalate, polyvinyl chloride, polyvinyl chloride Acrylamide, polyethylene oxide or polypropylene particles, the particle diameter of the polymer particles is 0.05-25um.
5. The non-aqueous electrolytic solution according to claim 2, wherein the mass content ratio of the shell of the additive is 0.1% to 99.9%.
6. The non-aqueous electrolyte solution according to claim 2, characterized in that, the solid particles of the core-shell structure may include one or more cores.
7. The non-aqueous electrolytic solution according to claim 1, characterized in that the additives are solid particles with an average particle diameter of 0.1-30 microns.
8. The non-aqueous electrolytic solution according to claim 1, wherein the mass proportion of the additive is 0.1%-30%.
9. The non-aqueous electrolytic solution according to claim 1, wherein the electrolytic solution comprises a non-aqueous solvent, a lithium salt and a second additive.
10. A lithium ion secondary battery, characterized in that the lithium ion secondary battery comprises the non-aqueous electrolytic solution according to any one of claims 1 to 9.