Electrolyte based on addition of 1, 4-butane sultone, preparation method and lithium ion battery thereof

Abstract

The invention relates to the technical field of electrolytes, in particular to an electrolyte based on addition of 1, 4-butane sultone, a preparation method of the electrolyte and a lithium ion battery of the electrolyte. The preparation method comprises the following steps: weighing raw materials in parts by weight: 45-50 parts of ethylene carbonate and 5-10 parts of 1, 4-butane sultone; the electrolyte comprises the following components in parts by weight: 1 part of 1, 4-butane sultone, 4-7 parts of a modifier, 5-8 parts of a filling agent, 5-8 parts of lithium hexafluorophosphate with the concentration of 1mol / L and 2-4 parts of methyl fluorosulfonyl difluoroacetate. The electrolyte obtained by the invention can realize excellent discharge capacity performance of a product under a high-rate condition in a battery, and meanwhile, the product has an obvious capacity retention rate effect after multiple cycles and an obvious corrosion-resistant stability effect.

Description

Technical Field

[0001] The present invention relates to the technical field of electrolytes, and particularly to an electrolyte based on the addition of 1,4-butanesultone, a preparation method thereof, and a lithium-ion battery. Background Art

[0002] The electrolyte of a lithium battery is an important component of the battery, which plays the role of transmitting charges between the positive and negative electrodes in the battery. It is crucial for the specific capacity, operating temperature range, cycle efficiency, and safety performance of the battery. The raw materials used in the existing lithium battery electrolytes are relatively conventional. When made into lithium batteries, they affect the discharge capacity performance of the battery under high-rate conditions. At the same time, the capacity retention rate of the product decreases significantly after multiple cycles, and the corrosion resistance and stability of the product are poor, which limits the use efficiency of the product. Based on this, the present invention makes further improvements. Summary of the Invention

[0003] Aiming at the defects of the prior art, the purpose of the present invention is to provide an electrolyte based on the addition of 1,4-butanesultone, a preparation method thereof, and a lithium-ion battery, so as to solve the problems raised in the above background art.

[0004] The present invention adopts the following technical solutions to solve the technical problems:

[0005] The present invention provides a preparation method of an electrolyte based on the addition of 1,4-butanesultone, including the following steps:

[0006] Step 1: Weigh the raw materials according to parts by weight:

[0007] Weigh 45-50 parts of ethylene carbonate, 5-10 parts of 1,4-butanesultone, 4-7 parts of a modifier, 5-8 parts of a filler, 5-8 parts of lithium hexafluorophosphate with a concentration of 1 mol / L, and 2-4 parts of methyl fluorosulfonyldifluoroacetate;

[0008] Step 2: First, uniformly blend 1,4-butanesultone, lithium hexafluorophosphate, methyl fluorosulfonyldifluoroacetate, and ethylene carbonate, and then add the modifier and the filler and continue to mix thoroughly to obtain the electrolyte of the present invention.

[0009] Preferably, the preparation method of the modifier is as follows:

[0010] S01: Heat-treat silicon carbide at 150-160 °C for 1 h. After the treatment is completed, air-cool it to room temperature, then place it in a sufficient amount of sulfuric acid solution and mix thoroughly, and then wash it with water, filter it by suction, and dry it;

[0011] S02: Immerse boron nitride in a yttrium nitrate solution 3-5 times the total amount of boron nitride and stir thoroughly, then filter it by suction and dry it to obtain a yttrium-doped boron nitride body;

[0012] S03: Blend 4 - 7 parts of the S01 product, 10 - 15 parts of a 5% sodium citrate solution by mass, 2 - 3 parts of yttrium-doped boron nitride, and 1 - 3 parts of sodium carboxymethylcellulose thoroughly, and finally perform suction filtration and drying to obtain the modifier.

[0013] Preferably, the mass fraction of the sulfuric acid solution is 2 - 5%; the mass fraction of the yttrium nitrate solution is 4 - 7%.

[0014] Preferably, the preparation method of the filler is as follows:

[0015] S101: Stir carbon nanotubes evenly in a sufficient amount of 8% hydrogen peroxide solution by mass, then perform suction filtration and drying, and preheat at 60 - 65 °C for 1 h to obtain pretreated carbon nanotubes;

[0016] Blend 5 - 8 parts of carbon fiber, 2 - 4 parts of cerium oxide, 1 - 2 parts of silane coupling agent KH560, and 6 - 10 parts of chitosan solution thoroughly to obtain carbon fiber liquid;

[0017] S102: Ultrasonically treat the pretreated carbon nanotubes and the carbon fiber liquid according to a weight ratio of 2:5. After the ultrasonic treatment, perform suction filtration and drying to obtain the modified carbon nanotube agent;

[0018] S103: Add 3 - 5 parts of kaolin agent to 5 - 8 parts of hydrochloric acid dopamine solution, and then add 1 - 3 parts of sodium metaborate and 2 - 4 parts of lanthanum chloride solution and blend thoroughly to obtain the intercalation and adjustment liquid;

[0019] S104: Mix and ball-mill the modified carbon nanotube agent and the intercalation and adjustment liquid according to a weight ratio of 5:3. The ball-milling speed is 1500 r / min, and ball-mill for 1 h. After the ball-milling is completed, perform suction filtration and drying to obtain the filler.

[0020] Preferably, the mass fraction of the chitosan solution is 2 - 5%; the ultrasonic power of the ultrasonic treatment is 350 - 400 W, and ultrasonic for 20 min.

[0021] Preferably, the mass fraction of the hydrochloric acid dopamine solution is 5 - 8%; the mass fraction of the lanthanum chloride solution is 2 - 5%.

[0022] Preferably, the preparation method of the kaolin agent is as follows:

[0023] Add 3 - 5 parts of kaolin and 2 - 3 parts of nano-titanium dioxide to 4 - 7 parts of sodium silicate aqueous solution, then add 1 - 2 parts of urea solution and 1 - 3 parts of aluminum nitride, and perform blending and stirring treatment. After the stirring is completed, perform suction filtration and drying to obtain the kaolin agent.

[0024] Preferably, the mass fraction of the sodium silicate aqueous solution is 2-5%; the mass fraction of the urea solution is 4-6%; the stirring speed of the blending and stirring treatment is 750-850 r / min, and stirring is carried out for 1 h.

[0025] The present invention also provides an electrolyte prepared by the preparation method of the electrolyte based on the addition of 1,4-butanesultone.

[0026] The present invention also provides a lithium-ion battery, including a positive electrode sheet, a negative electrode sheet, a separator and an electrolyte, wherein the electrolyte is an electrolyte prepared by the preparation method of the electrolyte according to any one of claims 1-8.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. In the preparation method of the electrolyte of the present invention, 1,4-butanesultone, lithium hexafluorophosphate, methyl fluorosulfonyldifluoroacetate and ethylene carbonate are used as matrix raw materials. By adding a modifier and a filler and coordinating them, the obtained electrolyte can achieve excellent discharge capacity performance of the product under high rate conditions in the battery. At the same time, the capacity retention rate of the product after multiple cycles is remarkable, and the corrosion resistance and stability effect of the product is obvious;

[0029] 2. In the preparation of the yttrium-doped boron nitride body, boron nitride is used as the matrix, and is improved and optimized by yttrium nitrate solution and rare earth raw materials, which is convenient for better blending and coordinating with silicon carbide, so as to better optimize the interfacial property of the system and the performance stability of the system;

[0030] 3. At the same time, the modifier is made of silicon carbide through heat improvement and acid solution activation, and then coordinated with the yttrium-doped boron nitride body, a 5% sodium citrate solution and sodium carboxymethylcellulose. Through the coordination and synergy of raw materials, the performance of the product is further improved;

[0031] 4. The filler is made of carbon nanotubes activated and improved by hydrogen peroxide solution, and at the same time, carbon fiber liquid is used for coordination. The carbon fiber, cerium oxide, silane coupling agent KH560 and chitosan solution in the carbon fiber liquid are coordinated with each other. Through the co - coordination and synergy of raw materials, the fiber needle - like structure of carbon fiber is used to blend with the carbon nanotubes with high specific surface area, enhancing the coordination and synergy effect between raw materials, enhancing the connectivity effect between system raw materials, and strengthening the structural property between systems, and enhancing the performance stability of the product;

[0032] 5. The intercalation liquid uses kaolin as a matrix, and is synergistically formulated with dopamine hydrochloride solution, sodium metaborate and lanthanum chloride solution. The active performance effects of the products are enhanced through the co-formulation and synergy between raw materials such as dopamine hydrochloride solution. At the same time, the kaolin, nano-titanium dioxide and aluminum nitride in the kaolin agent are co-blended with sodium silicate aqueous solution and urea solution. The lamellar kaolin structure is used to blend nano-titanium oxide and aluminum nitride. In the system, the high specific surface area structure of carbon nanotubes can be used for loading, thereby optimizing the system performance stability. The co-formulation and synergy between the raw materials enhances the synergistic effect of the kaolin agent in the intercalation liquid, thereby further improving the performance of the product. DETAILED DESCRIPTION

[0033] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with specific embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0034] The preparation method of the electrolyte solution based on the addition of 1,4-butane sultone in this embodiment includes the following steps:

[0035] Step 1: weigh the raw materials according to weight:

[0036] Weigh 45-50 parts of ethylene carbonate, 5-10 parts of 1,4-butane sultone, 4-7 parts of a performance modifier, 5-8 parts of a filler, 5-8 parts of 1 mol / L lithium hexafluorophosphate, and 2-4 parts of methyl fluorosulfonyl difluoroacetate;

[0037] Step 2: 1,4-butanesulfonate, lithium hexafluorophosphate, methyl fluorosulfonyl difluoroacetate and ethylene carbonate are uniformly mixed, and then a performance-improving agent and a filler are added and mixed thoroughly to obtain the electrolyte of the present invention.

[0038] The preparation method of the performance-improving agent of this embodiment is:

[0039] S01: Heat treat silicon carbide at 150-160°C for 1 hour. After the treatment, air cool it to room temperature and then place it in a sufficient amount of sulfuric acid solution to mix thoroughly. Then, wash it with water, filter it, and dry it.

[0040] S02: immersing the boron nitride in an yttrium nitrate solution 3 to 5 times the total amount of the boron nitride and stirring thoroughly, then filtering and drying to obtain an yttrium-doped boron nitride body;

[0041] S03: Blend 4 - 7 parts of the S01 product, 10 - 15 parts of a 5% sodium citrate solution by mass, 2 - 3 parts of yttrium-doped boron nitride, and 1 - 3 parts of sodium carboxymethylcellulose thoroughly, and finally perform suction filtration and drying to obtain the modifier.

[0042] In this embodiment, the mass fraction of the sulfuric acid solution is 2 - 5%; the mass fraction of the yttrium nitrate solution is 4 - 7%.

[0043] The preparation method of the filler in this embodiment is as follows:

[0044] S101: Stir carbon nanotubes evenly in a sufficient amount of 8% hydrogen peroxide solution by mass, then perform suction filtration and drying, and preheat at 60 - 65 °C for 1 h to obtain pretreated carbon nanotubes;

[0045] Blend 5 - 8 parts of carbon fiber, 2 - 4 parts of cerium oxide, 1 - 2 parts of silane coupling agent KH560, and 6 - 10 parts of chitosan solution thoroughly to obtain a carbon fiber liquid;

[0046] S102: Ultrasonically treat the pretreated carbon nanotubes and the carbon fiber liquid according to a weight ratio of 2:5. After the ultrasonic treatment, perform suction filtration and drying to obtain a modified carbon nanotube agent;

[0047] S103: Add 3 - 5 parts of kaolin agent to 5 - 8 parts of hydrochloric acid dopamine solution, and then add 1 - 3 parts of sodium metaborate and 2 - 4 parts of lanthanum chloride solution and blend thoroughly to obtain an intercalation and adjustment liquid;

[0048] S104: Mix and ball-mill the modified carbon nanotube agent and the intercalation and adjustment liquid according to a weight ratio of 5:3. The ball-milling speed is 1500 r / min, and ball-mill for 1 h. After the ball-milling is completed, perform suction filtration and drying to obtain the filler.

[0049] In this embodiment, the mass fraction of the chitosan solution is 2 - 5%; the ultrasonic power of the ultrasonic treatment is 350 - 400 W, and ultrasonic for 20 min.

[0050] In this embodiment, the mass fraction of the hydrochloric acid dopamine solution is 5 - 8%; the mass fraction of the lanthanum chloride solution is 2 - 5%.

[0051] The preparation method of the kaolin agent in this embodiment is as follows:

[0052] Add 3 - 5 parts of kaolin and 2 - 3 parts of nano-titanium dioxide to 4 - 7 parts of sodium silicate aqueous solution, and then add 1 - 2 parts of urea solution and 1 - 3 parts of aluminum nitride, and perform blending and stirring treatment. After the stirring is completed, perform suction filtration and drying to obtain the kaolin agent.

[0053] In this embodiment, the mass fraction of the sodium silicate aqueous solution is 2-5%; the mass fraction of the urea solution is 4-6%; the stirring speed for the blending and stirring treatment is 750-850 r / min, and the stirring is carried out for 1 h.

[0054] The electrolyte prepared by the preparation method of the electrolyte based on the addition of 1,4-butanesultone in this embodiment.

[0055] A lithium-ion battery in this embodiment includes a positive electrode sheet, a negative electrode sheet, a separator, and an electrolyte. The electrolyte is the electrolyte prepared by the preparation method of the electrolyte according to any one of claims 1-8.

[0056] Example 1.

[0057] The preparation method of the electrolyte based on the addition of 1,4-butanesultone in this embodiment includes the following steps:

[0058] Step 1: Weigh the raw materials according to parts by weight:

[0059] Weigh 45 parts of ethylene carbonate, 5 parts of 1,4-butanesultone, 4 parts of modifier, 5 parts of filler, 5 parts of lithium hexafluorophosphate with a concentration of 1 mol / L, and 2 parts of methyl fluorosulfonyldifluoroacetate;

[0060] Step 2: First, blend 1,4-butanesultone, lithium hexafluorophosphate, methyl fluorosulfonyldifluoroacetate, and ethylene carbonate evenly, and then add the modifier and filler and continue to mix thoroughly to obtain the electrolyte of the present invention.

[0061] The preparation method of the modifier in this embodiment is:

[0062] S01: Heat-treat silicon carbide at 150 °C for 1 h. After the treatment is completed, air-cool it to room temperature, then place it in a sufficient amount of sulfuric acid solution and mix evenly, and then wash, filter by suction, and dry;

[0063] S02: Immerse boron nitride in a yttrium nitrate solution 3 times the total amount of boron nitride and stir thoroughly, then filter by suction and dry to obtain a yttrium-doped boron nitride body;

[0064] Blend 4 parts of the product of S01, 10 parts of a 5% sodium citrate solution, 2 parts of the yttrium-doped boron nitride body, and 1 part of sodium carboxymethylcellulose thoroughly to obtain the modifier.

[0065] In this embodiment, the mass fraction of the sulfuric acid solution is 2%; the mass fraction of the yttrium nitrate solution is 4%.

[0066] The preparation method of the filler in this embodiment is:

[0067] S101: stirring the carbon nanotubes uniformly in a sufficient amount of 8% by mass hydrogen peroxide solution, then filtering and drying, and then preheating at 60° C. for 1 hour to obtain pretreated carbon nanotubes;

[0068] 5 parts of carbon fiber, 2 parts of cerium oxide, 1 part of silane coupling agent KH560 and 6 parts of chitosan solution were fully blended to obtain a carbon fiber solution;

[0069] S102: ultrasonically treating the pretreated carbon nanotube and carbon fiber liquid in a weight ratio of 2:5. After the ultrasonic treatment is completed, the mixture is filtered and dried to obtain a modified carbon nanotube agent.

[0070] S103: adding 3 parts of kaolin agent to 5 parts of dopamine hydrochloride solution, and then adding 1 part of sodium metaborate and 2 parts of lanthanum chloride solution and mixing thoroughly to obtain an intercalation solution;

[0071] S104: The modified carbon nanotube agent and the intercalation liquid are mixed in a weight ratio of 5:3 and subjected to ball milling at a ball milling speed of 1500 r / min for 1 hour. After the ball milling is completed, the mixture is filtered and dried to obtain a filling agent.

[0072] The mass fraction of the chitosan solution in this embodiment is 2%; the ultrasonic power of the ultrasonic treatment is 350W, and the ultrasonic treatment lasts for 20 minutes.

[0073] The mass fraction of the dopamine hydrochloride solution in this embodiment is 5%; the mass fraction of the lanthanum chloride solution is 2%.

[0074] The preparation method of the kaolin agent of this embodiment is:

[0075] 3 parts of kaolin and 2 parts of nano-titanium dioxide are added to 4 parts of sodium silicate aqueous solution, and then 1 part of urea solution and 1 part of aluminum nitride are added, and the mixture is mixed and stirred. After stirring is completed, the mixture is filtered and dried to obtain a kaolin agent.

[0076] The mass fraction of the sodium silicate aqueous solution in this embodiment is 2%; the mass fraction of the urea solution is 4%.

[0077] The stirring speed of the blending and stirring process in this embodiment is 750 r / min, and the stirring is carried out for 1 hour.

[0078] The electrolyte of this embodiment is prepared by the method for preparing an electrolyte with the addition of 1,4-butane sultone.

[0079] A lithium-ion battery of this embodiment includes a positive electrode sheet, a negative electrode sheet, a separator, and an electrolyte, wherein the electrolyte is prepared according to the method for preparing an electrolyte according to any one of claims 1 to 8.

[0080] Example 2.

[0081] The preparation method of the electrolyte based on the addition of 1,4-butanesultone in this embodiment includes the following steps:

[0082] Step 1: Weigh the raw materials according to parts by weight:

[0083] Weigh 50 parts of ethylene carbonate, 10 parts of 1,4-butanesultone, 7 parts of modifier, 8 parts of filler, 8 parts of lithium hexafluorophosphate with a concentration of 1 mol / L, and 4 parts of methyl fluorosulfonyldifluoroacetate;

[0084] Step 2: First, uniformly blend 1,4-butanesultone, lithium hexafluorophosphate, methyl fluorosulfonyldifluoroacetate, and ethylene carbonate, and then add the modifier and filler and continue to mix thoroughly to obtain the electrolyte of the present invention.

[0085] The preparation method of the modifier in this embodiment is as follows:

[0086] S01: Heat-treat silicon carbide at 160 °C for 1 h. After the treatment is completed, air-cool it to room temperature, then place it in a sufficient amount of sulfuric acid solution and mix well, and then wash, filter, and dry it;

[0087] S02: Immerse boron nitride in a yttrium nitrate solution 5 times the total amount of boron nitride and stir well, then filter and dry to obtain a yttrium-doped boron nitride body;

[0088] Mix 7 parts of the product of S01, 15 parts of a 5% sodium citrate solution, 3 parts of the yttrium-doped boron nitride body, and 3 parts of sodium carboxymethylcellulose thoroughly to obtain the modifier.

[0089] The mass fraction of the sulfuric acid solution in this embodiment is 5%; the mass fraction of the yttrium nitrate solution is 7%.

[0090] The preparation method of the filler in this embodiment is as follows:

[0091] S101: Stir carbon nanotubes evenly in a sufficient amount of hydrogen peroxide solution with a mass fraction of 8%, then filter and dry, and then preheat at 65 °C for 1 h to obtain pretreated carbon nanotubes;

[0092] Mix 8 parts of carbon fiber, 4 parts of cerium oxide, 2 parts of silane coupling agent KH560, and 10 parts of chitosan solution thoroughly to obtain a carbon fiber solution;

[0093] S102: Ultrasonically treat the pretreated carbon nanotubes and the carbon fiber solution according to a weight ratio of 2:5. After the ultrasonic treatment is completed, filter and dry to obtain a modified carbon nanotube agent;

[0094] S103: Add 5 parts of kaolin agent to 8 parts of hydrochloric acid dopamine solution, and then add 3 parts of sodium metaborate and 4 parts of lanthanum chloride solution and mix thoroughly to obtain an intercalation and adjustment solution;

[0095] S104: The modified carbon nanotube agent and the intercalation liquid are mixed in a weight ratio of 5:3 and subjected to ball milling at a ball milling speed of 1500 r / min for 1 hour. After the ball milling is completed, the mixture is filtered and dried to obtain a filling agent.

[0096] The mass fraction of the chitosan solution in this embodiment is 5%; the ultrasonic power of the ultrasonic treatment is 400 W, and the ultrasonic treatment lasts for 20 minutes.

[0097] The mass fraction of the dopamine hydrochloride solution in this embodiment is 8%; the mass fraction of the lanthanum chloride solution is 5%.

[0098] The preparation method of the kaolin agent of this embodiment is:

[0099] 5 parts of kaolin and 3 parts of nano-titanium dioxide are added to 7 parts of sodium silicate aqueous solution, and then 2 parts of urea solution and 3 parts of aluminum nitride are added, and the mixture is mixed and stirred. After stirring is completed, the mixture is filtered and dried to obtain a kaolin agent.

[0100] The mass fraction of the sodium silicate aqueous solution in this embodiment is 5%; the mass fraction of the urea solution is 6%.

[0101] The stirring speed of the blending and stirring process in this embodiment is 850 r / min, and the stirring is carried out for 1 hour.

[0102] The electrolyte of this embodiment is prepared by the method for preparing an electrolyte with the addition of 1,4-butane sultone.

[0103] A lithium-ion battery of this embodiment includes a positive electrode sheet, a negative electrode sheet, a separator, and an electrolyte, wherein the electrolyte is prepared according to the method for preparing an electrolyte according to any one of claims 1 to 8.

[0104] Example 3.

[0105] The preparation method of the electrolyte solution based on the addition of 1,4-butane sultone in this embodiment includes the following steps:

[0106] Step 1: weigh the raw materials according to weight:

[0107] Weigh 47.5 parts of ethylene carbonate, 7.5 parts of 1,4-butane sultone, 5.5 parts of a performance modifier, 6.5 parts of a filler, 6.5 parts of 1 mol / L lithium hexafluorophosphate, and 3 parts of methyl fluorosulfonyl difluoroacetate;

[0108] Step 2: 1,4-butanesulfonate, lithium hexafluorophosphate, methyl fluorosulfonyl difluoroacetate and ethylene carbonate are uniformly mixed, and then a performance-improving agent and a filler are added and mixed thoroughly to obtain the electrolyte of the present invention.

[0109] The preparation method of the performance-improving agent of this embodiment is:

[0110] S01: heat-treat silicon carbide at 155°C for 1 hour, cool it to room temperature, and then place it in a sufficient amount of sulfuric acid solution to mix thoroughly, then wash it with water, filter it, and dry it;

[0111] S02: immersing the boron nitride in an yttrium nitrate solution with a volume 4 times the total volume of the boron nitride and stirring thoroughly, then filtering and drying to obtain an yttrium-doped boron nitride body;

[0112] 5.5 parts of S01 product, 12.5 parts of 5% by mass sodium citrate solution, 2.5 parts of yttrium-doped boron nitride and 2 parts of sodium carboxymethyl cellulose were fully mixed to obtain a performance-improving agent.

[0113] The mass fraction of the sulfuric acid solution in this embodiment is 3.5%; the mass fraction of the yttrium nitrate solution is 5.5%.

[0114] The preparation method of the filling agent of this embodiment is:

[0115] S101: stirring the carbon nanotubes in a sufficient amount of 8% by mass hydrogen peroxide solution, then filtering and drying, and then preheating at 62.5° C. for 1 hour to obtain pretreated carbon nanotubes;

[0116] 6.5 parts of carbon fiber, 3 parts of cerium oxide, 1.5 parts of silane coupling agent KH560 and 8 parts of chitosan solution were fully blended to obtain a carbon fiber solution;

[0117] S102: ultrasonically treating the pretreated carbon nanotube and carbon fiber liquid in a weight ratio of 2:5. After the ultrasonic treatment is completed, the mixture is filtered and dried to obtain a modified carbon nanotube agent.

[0118] S103: adding 4 parts of kaolin agent to 6.5 parts of dopamine hydrochloride solution, and then adding 2 parts of sodium metaborate and 3 parts of lanthanum chloride solution and mixing thoroughly to obtain an intercalation solution;

[0119] S104: The modified carbon nanotube agent and the intercalation liquid are mixed in a weight ratio of 5:3 and subjected to ball milling at a ball milling speed of 1500 r / min for 1 hour. After the ball milling is completed, the mixture is filtered and dried to obtain a filling agent.

[0120] The mass fraction of the chitosan solution in this embodiment is 3.5%; the ultrasonic power of the ultrasonic treatment is 375W, and the ultrasonic treatment lasts for 20 minutes.

[0121] The mass fraction of the dopamine hydrochloride solution in this embodiment is 6.5%; the mass fraction of the lanthanum chloride solution is 3.5%.

[0122] The preparation method of the kaolin agent of this embodiment is:

[0123] 4 parts of kaolin and 2.5 parts of nano-titanium dioxide were added to 5.5 parts of sodium silicate aqueous solution, and then 1.5 parts of urea solution and 2 parts of aluminum nitride were added, followed by blending and stirring. After stirring, filtration and drying were carried out to obtain the kaolin agent.

[0124] In this example, the mass fraction of the sodium silicate aqueous solution is 3.5%; the mass fraction of the urea solution is 5%.

[0125] In this example, the stirring speed of the blending and stirring process is 800 r / min, and the stirring time is 1 h.

[0126] The electrolyte prepared by the preparation method of the electrolyte added with 1,4-butane sultone in this example.

[0127] A lithium-ion battery in this example includes a positive electrode sheet, a negative electrode sheet, a separator and an electrolyte, and the electrolyte is the electrolyte prepared by the preparation method of the electrolyte according to any one of claims 1 to 8.

[0128] Comparative Example 1.

[0129] The difference from Example 3 is that the modifier is not added.

[0130] Comparative Example 2.

[0131] The difference from Example 3 is that the S01 product is not added to the modifier.

[0132] Comparative Example 3.

[0133] The difference from Example 3 is that the boron nitride doped with yttrium is not added to the modifier.

[0134] Comparative Example 4.

[0135] The difference from Example 3 is that the filler is not added.

[0136] Comparative Example 5.

[0137] The difference from Example 3 is that the modified carbon nanotube agent is not added to the filler.

[0138] Comparative Example 6.

[0139] The difference from Example 3 is that the pretreated carbon nanotubes are not added in the preparation of the modified carbon nanotube agent.

[0140] Comparative Example 7.

[0141] The difference from Example 3 is that the carbon fiber liquid is not added in the preparation of the modified carbon nanotube agent.

[0142] Comparative Example 8.

[0143] The difference from Example 3 is that the intercalation adjusting liquid is not added to the filler.

[0144] Comparative Example 9

[0145] Different from Example 3, sodium metaborate and lanthanum chloride solution were not added to the interpolation adjusting solution.

[0146] Comparative Example 10

[0147] Different from Example 3, kaolin agent was not added to the interpolation adjusting solution.

[0148] The products of Examples 1 to 3 and Comparative Examples 1 to 10 were assembled into batteries with reference to the existing technology, the charge-discharge rate was 2C, the charge-discharge voltage range was 3 - 4.35V, and performance tests were carried out. The test results are as follows

[0149]

[0150]

[0151] On the basis of the above performance tests, the products were further placed under 5% hydrochloric acid mist for 12h to test their acid corrosion resistance performance;

[0152]

[0153] It can be seen from Comparative Examples 1 to 10 and Examples 1 to 3;

[0154] The products of Example 3 have excellent 2C discharge capacity. At the same time, under the conditions of 200 cycles and 500 cycles, the capacity retention rate of the products is excellent, and the two can be coordinately improved. In addition, the product has excellent performance stability under acid corrosion conditions;

[0155] When the improver and the filling agent are not added in the present invention, the performance of the product deteriorates significantly, and the acid corrosion resistance stability of the product decreases significantly. By using the coordinated treatment of the improver and the filling agent, the synergistic effect is achieved, and the performance of the product is improved significantly;

[0156] When the S01 product is not added to the improver and the boron nitride doped with yttrium is not added to the improver, the performance of the product shows a deteriorating trend;

[0157] When the modified carbon nanotube agent is not added to the filling agent, the pretreated carbon nanotube is not added in the preparation of the modified carbon nanotube agent, the carbon fiber liquid is not added in the preparation of the modified carbon nanotube agent, the interpolation adjusting solution is not added to the filling agent, sodium metaborate and lanthanum chloride solution are not added to the interpolation adjusting solution, and kaolin agent is not added to the interpolation adjusting solution, the performance of the product shows a deteriorating trend to varying degrees. The modified carbon nanotube agent prepared by combining the modified carbon nanotube agent and the carbon fiber liquid obtained by the specific method of the present invention, and the product raw materials obtained by using the specific interpolation adjusting solution have the most significant performance effect. Using other methods to replace them is not as obvious as the effect of the present invention. At the same time, when kaolin agent is not added to the interpolation adjusting solution, the performance of the product also shows a relatively obvious deteriorating trend.

[0158] Based on the fact that the kaolin agent has a relatively large impact on the product performance trend, the present invention further explores the product performance through the preparation of the kaolin agent;

[0159] Experimental Example 1.

[0160] The only difference from Example 3 is that kaolin is not added to the kaolin agent.

[0161] Experimental Example 2.

[0162] The only difference from Example 3 is that nano-titanium dioxide is not added to the kaolin agent.

[0163] Experimental Example 3.

[0164] The only difference from Example 3 is that aluminum nitride is not added to the kaolin agent.

[0165] Experimental Example 4.

[0166] The only difference from Example 3 is that an aqueous solution of sodium silicate is not added to the kaolin agent.

[0167] Experimental Example 5.

[0168] The only difference from Example 3 is that a urea solution is not added to the kaolin agent.

[0169] Based on the product acid and corrosion resistance test, continue to test the results of the preparation of the kaolin agent on the product performance;

[0170]

[0171] It can be seen from Experimental Examples 1 to 5 that when kaolin is not added in the preparation of the kaolin agent, the performance of the product changes. Among the preparation factors of the kaolin agent, the performance deterioration is the most obvious. Secondly, when aluminum nitride is not added to the kaolin agent, and at the same time when nano-titanium dioxide is not added to the kaolin agent, the performance of the product all shows a deteriorating trend. Therefore, the raw material selection of the kaolin agent has specificity. At the same time, it is also found that when an aqueous solution of sodium silicate is not added to the kaolin agent and when a urea solution is not added to the kaolin agent, the performance of the product all shows a deteriorating trend. Only the kaolin agent prepared by the specific method of the present invention has the most significant product performance effect, and replacing the kaolin agent with other methods is not as effective as the present invention.

[0172] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, it is intended to include all changes falling within the meaning and scope of the equivalent elements of the claims in the present invention.

[0173] In addition, it should be understood that although this specification is described in terms of embodiments, not every embodiment contains only an independent technical solution. This narrative style of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for preparing an electrolyte added with 1,4-butanesultone, characterized in that, It includes the following steps: Step 1: Weigh the raw materials by weight parts: Weigh 45 - 50 parts of ethylene carbonate, 5 - 10 parts of 1,4 - butane sultone, 4 - 7 parts of modifier, 5 - 8 parts of filler, 5 - 8 parts of lithium hexafluorophosphate with a concentration of 1 mol / L, and 2 - 4 parts of methyl fluorosulfonyldifluoroacetate; Step 2: First, mix 1,4 - butane sultone, lithium hexafluorophosphate, methyl fluorosulfonyldifluoroacetate, and ethylene carbonate evenly, and then add the modifier and filler and continue to mix thoroughly to obtain the electrolyte of the present invention.

2. The preparation method of the electrolyte based on the addition of 1,4-butanesultone according to claim 1, wherein, The preparation method of the said modifier is: S01: Heat - treat silicon carbide at 150 - 160 °C for 1 h. After the treatment, cool it to room temperature in air, then place it in a sufficient amount of sulfuric acid solution and mix thoroughly, and then wash, filter by suction, and dry; S02: Immerse boron nitride into a yttrium nitrate solution 3 - 5 times the total amount of boron nitride and stir thoroughly, then filter by suction and dry to obtain a yttrium - doped boron nitride body; S03: Mix 4 - 7 parts of the product of S01, 10 - 15 parts of a 5% sodium citrate solution by mass, 2 - 3 parts of the yttrium - doped boron nitride body, and 1 - 3 parts of sodium carboxymethyl cellulose thoroughly, and finally filter by suction and dry to obtain the modifier.

3. The preparation method of the electrolyte based on the addition of 1,4-butanesultone according to claim 2, wherein, The mass fraction of the said sulfuric acid solution is 2 - 5%; the mass fraction of the yttrium nitrate solution is 4 - 7%.

4. The preparation method of the electrolyte based on the addition of 1,4-butane sultone according to claim 1, characterized in that, The preparation method of the said filler is: S101: Stir carbon nanotubes evenly in a sufficient amount of 8% hydrogen peroxide solution by mass, then filter by suction and dry, and then pre - heat at 60 - 65 °C for 1 h to obtain pretreated carbon nanotubes; Mix 5 - 8 parts of carbon fiber, 2 - 4 parts of cerium oxide, 1 - 2 parts of silane coupling agent KH560, and 6 - 10 parts of chitosan solution thoroughly to obtain a carbon fiber solution; S102: Ultrasonically treat the pretreated carbon nanotubes and the carbon fiber solution according to a weight ratio of 2:

5. After the ultrasonic treatment, filter by suction and dry to obtain a modified carbon nanotube agent; S103: Add 3 - 5 parts of kaolin agent to 5 - 8 parts of hydrochloric acid dopamine solution, and then add 1 - 3 parts of sodium metaborate and 2 - 4 parts of lanthanum chloride solution and mix thoroughly to obtain an intercalation - adjusted solution; S104: Mix and ball - mill the modified carbon nanotube agent and the intercalation - adjusted solution according to a weight ratio of 5:

3. The ball - milling speed is 1500 r / min, and ball - mill for 1 h. After the ball - milling, filter by suction and dry to obtain the filler.

5. The preparation method of the electrolyte based on the addition of 1,4-butanesultone according to claim 4, characterized in that, The mass fraction of the said chitosan solution is 2 - 5%; the ultrasonic power of the ultrasonic treatment is 350 - 400 W, and ultrasonic for 20 min.

6. The preparation method of the electrolyte based on the addition of 1,4-butanesultone according to claim 4, wherein, The mass fraction of the said hydrochloric acid dopamine solution is 5 - 8%; the mass fraction of the lanthanum chloride solution is 2 - 5%.

7. The preparation method of the electrolyte based on the addition of 1,4-butane sultone according to claim 4, characterized in that, The preparation method of the said kaolin agent is: Add 3 - 5 parts of kaolin and 2 - 3 parts of nano - titanium dioxide to 4 - 7 parts of sodium silicate aqueous solution, then add 1 - 2 parts of urea solution and 1 - 3 parts of aluminum nitride, and mix and stir. After the stirring, filter by suction and dry to obtain the kaolin agent.

8. The preparation method of the electrolyte based on the addition of 1,4-butanesultone according to claim 7, characterized in that, The mass fraction of the said sodium silicate aqueous solution is 2 - 5%; the mass fraction of the urea solution is 4 - 6%; the stirring speed of the mixing and stirring is 750 - 850 r / min, and stir for 1 h.

9. The electrolyte prepared by the preparation method of the electrolyte based on the addition of 1,4-butanesultone according to any one of claims 1 to 8.

10. A lithium-ion battery, comprising a positive electrode sheet, a negative electrode sheet, a separator, and an electrolyte, characterized in that, The electrolyte is the electrolyte prepared by the preparation method of the electrolyte according to any one of claims 1 to 8.

Images