Modified magnesium hydroxide and preparation method thereof, lithium battery edge coating pole piece and lithium battery

Abstract

The invention discloses modified magnesium hydroxide and a preparation method thereof, a lithium battery edge coating pole piece and a lithium battery, and relates to the technical field of lithium ion batteries. According to the invention, magnesium hydroxide is modified by using the specific modification additive, and the use amount of the modification additive is regulated, so that impurity metal cations of magnesium hydroxide can be effectively removed, PVDF is prevented from deteriorating and discoloring, and the stability and safety of the material are ensured. The modified magnesium hydroxide is coated on the pole piece, the coating has good flexibility and adhesive force, material falling can be avoided during cutting and folding, the risk that the coating falls off due to factors such as vibration in the use process of the pole piece is reduced, the coating has good electrolyte tolerance, and the coating does not fall off after being soaked in electrolyte for 72 hours.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium ion batteries, and in particular to modified magnesium hydroxide and a preparation method thereof, a lithium battery edge-coated pole piece and a lithium battery. Background Art

[0002] Lithium-ion batteries have the characteristics of high specific energy, high voltage, small size and light weight. In recent years, they have been widely used in consumer electronics, new energy vehicles and rail transportation. In order to reduce the internal resistance of lithium-ion secondary batteries and increase the energy density of the battery, the current mainstream battery adopts multi-electrode battery technology, that is, the end is welded to form a pole ear bundle connected to the electrode terminal. During the cutting and trimming process, the pole ear is prone to edge burrs and the insulation edge coating falls off due to processing or material problems, resulting in battery short circuit and affecting the safety performance of the battery.

[0003] The raw materials used for the electrode edge coating are mainly solid powder boehmite, PVDF and solvent NMP. In recent years, magnesium hydroxide has gradually begun to be used in the field of electrode edge coating as a substitute for boehmite. Compared with boehmite, magnesium hydroxide has lower cost and has broad application prospects in the future.

[0004] However, after magnesium hydroxide and PVDF (polyvinylidene fluoride) are mixed and added to NMP (methyl pyrrolidone) solvent, the slurry tends to appear pink, gray or gel after high-speed stirring for a certain period of time. This is mainly because the introduction of magnesium hydroxide sometimes causes the deterioration of PVDF, and the slurry after discoloration or even gel is not only difficult to produce, but also causes the compressive strength of the pole piece to decrease, the risk of short circuit to increase, and the adhesion of the pole piece coating to deteriorate and easy to fall off.

[0005] Therefore, there is an urgent need to solve the problems of discoloration and gelation when magnesium hydroxide is used in the electrode edge coating, so that the electrode coating has good flexibility and adhesion.

[0006] In view of this, the present invention is proposed. Summary of the invention

[0007] The purpose of the present invention is to provide modified magnesium hydroxide and a preparation method thereof, a lithium battery edge-coated pole piece and a lithium battery, aiming to solve the problems of discoloration and gelation when magnesium hydroxide is applied to the edge coating of the pole piece, and at the same time make the pole piece coating have good flexibility and adhesion.

[0008] The present invention is achieved in that:

[0009] In a first aspect, the present invention provides a modified magnesium hydroxide, comprising magnesium hydroxide and a modification aid, wherein the mass ratio of the modification aid to the magnesium hydroxide is (0.1-1.0):100;

[0010] The modification aid is selected from at least one of methanesulfonic acid, ethanesulfonic acid, trifluoromethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, naphthalenesulfonic acid and phenylbenzimidazolesulfonic acid.

[0011] In an optional embodiment, the mass ratio of the modification aid to magnesium hydroxide is (0.3-0.7):100;

[0012] Wherein, the modification aid is selected from at least one of methanesulfonic acid, ethanesulfonic acid and trifluoromethanesulfonic acid.

[0013] In a second aspect, the present invention provides a method for preparing the modified magnesium hydroxide according to the aforementioned embodiment, comprising: modifying the magnesium hydroxide using a modification aid.

[0014] In an optional embodiment, the method comprises: using a magnesium salt solution and an alkali solution to react and age to obtain a magnesium hydroxide reaction body slurry;

[0015] The magnesium hydroxide reaction body slurry and the modification aid are mixed and stirred to obtain a modified slurry; wherein the mass ratio of the modification aid to the theoretical amount of magnesium hydroxide in the magnesium hydroxide reaction body slurry is controlled to be (0.1-1.0):100;

[0016] The modified slurry is washed and then dried.

[0017] In an optional embodiment, the process of preparing a magnesium hydroxide reaction body slurry includes: first preheating a magnesium salt solution to 60°C-100°C, dropwise adding an alkali solution at a temperature of 60°C-100°C into the magnesium salt solution, reacting at 60°C-100°C for 1h-10h, and then aging the reaction at 15°C-35°C for 2h-24h.

[0018] In an optional embodiment, the magnesium salt solution is obtained by mixing a soluble magnesium salt and water, and the soluble magnesium salt is selected from at least one of magnesium chloride, magnesium carbonate, magnesium nitrate and magnesium sulfate;

[0019] And / or, the alkali solution is selected from at least one of a sodium hydroxide solution, an ammonia solution and a potassium hydroxide solution.

[0020] In an optional embodiment, during the preparation of the modified slurry, the magnesium hydroxide reactant slurry and the modification aid are mixed and stirred for 1 h to 2 h.

[0021] In an optional embodiment, the modified pulp is washed with water to a pH value of 7-10 and then spray-dried.

[0022] In a third aspect, the present invention provides a lithium battery edge-coated electrode, comprising an electrode substrate and a coating located on at least one side of the electrode substrate, wherein the coating comprises any of the modified magnesium hydroxide in the aforementioned embodiments or the modified magnesium hydroxide prepared by any of the preparation methods in the aforementioned embodiments.

[0023] In a fourth aspect, the present invention provides a lithium battery, comprising the edge-coated electrode of the lithium-ion battery of the aforementioned embodiment.

[0024] The present invention has the following beneficial effects: the present invention uses a specific modification auxiliary agent to modify magnesium hydroxide, and regulates the dosage of the modification auxiliary agent, which can effectively remove the metal cations impurities in magnesium hydroxide, prevent PVDF from deteriorating and discoloring, and ensure the stability and safety of the material. The modified magnesium hydroxide is coated on the pole piece, and the coating has good flexibility and adhesion, and can be cut and folded without falling off, which helps to reduce the risk of the coating falling off due to factors such as vibration during the use of the pole piece, and has good electrolyte tolerance. The coating does not fall off after being immersed in the electrolyte for 72 hours. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 This is a SEM image of the modified magnesium hydroxide prepared in Example 1;

[0027] Figure 2 This is the SEM image of the modified magnesium hydroxide prepared in Comparative Example 4. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0029] In the prior art, after magnesium hydroxide and PVDF are mixed and added to NMP solvent for high-speed stirring for a certain period of time, the slurry is prone to pink, gray or gel. In view of this problem, the present invention modifies magnesium hydroxide and uses modified magnesium hydroxide instead of magnesium hydroxide in the prior art to prepare the electrode edge coating, which can effectively solve the above problem.

[0030] The embodiment of the present invention provides a method for preparing modified magnesium hydroxide, wherein magnesium hydroxide is modified using a modification aid, and the steps are as follows:

[0031] S1. Preparation of magnesium hydroxide reaction body slurry

[0032] The magnesium hydroxide reaction body slurry is obtained by reacting and aging a magnesium salt solution with an alkali solution. High-purity magnesium hydroxide is prepared by reacting a magnesium salt with a high purity with an alkali solution, and the high-purity magnesium hydroxide is used for subsequent modification work, which can improve the purity of the modified product compared to directly using commercially purchased magnesium hydroxide as a raw material.

[0033] In some embodiments, the process of preparing the magnesium hydroxide reaction body slurry includes: preheating the magnesium salt solution to 60°C-100°C, adding an alkali solution at a temperature of 60°C-100°C to the magnesium salt solution, reacting at 60°C-100°C for 1h-10h, and then aging the reaction at 15°C-35°C for 2h-24h. The reaction is fully carried out by adjusting the reaction temperature, reaction time, aging time and other conditions.

[0034] Specifically, the magnesium salt solution is preheated before mixing with the alkali solution to reach the reaction temperature. The preheated temperature or reaction temperature can be 60°C, 70°C, 80°C, 90°C, 100°C, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable. The reaction time can be 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable. The alkali solution is also preheated to the reaction temperature before being added dropwise, so that the overall reaction temperature is easy to control. Aging can be carried out at room temperature, and the specific temperature can be 15°C, 20°C, 25°C, 30°C, 35°C, etc. The aging reaction time can be 2h, 4h, 6h, 8h, 10h, 12h, 14h, 16h, 18h, 20h, 22h, 24h, etc. The aging temperature and time are not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0035] The particle size of the particles in the magnesium hydroxide reaction body slurry is 0.6 to 1.5 μm, for example 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1 μm, 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm, 1.5 μm, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0036] Further, the magnesium salt solution is obtained by mixing a soluble magnesium salt and water, the soluble magnesium salt is selected from at least one of magnesium chloride, magnesium carbonate, magnesium nitrate and magnesium sulfate, the soluble magnesium salt can be any one or more of the above, can be dissolved in pure water at room temperature and pressure, and is easy to carry out aging reaction. The alkali solution is selected from at least one of sodium hydroxide solution, ammonia solution and potassium hydroxide solution, the alkali solution can be any one or more of the above, and the above solutions are all aqueous solutions.

[0037] Specifically, the soluble magnesium salt is dissolved in deionized water, filtered and purified, and preheated to ensure the formation of a high-purity precursor solution. The preheating is for better reaction. After that, the preheated high-purity alkali solution is added dropwise, and the uniformity and consistency of the material particles are ensured by continuous stirring. After aging reaction, the reaction is ensured to be complete. The addition of the modifier helps to separate the impurity ions in the material, and then after washing, the modified high-purity magnesium hydroxide is obtained.

[0038] S2. Preparation of modified slurry

[0039] The magnesium hydroxide reaction body slurry and the modification aid are mixed and stirred to obtain a modified slurry. The modification aid is selected from at least one of methanesulfonic acid, ethanesulfonic acid, trifluoromethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, naphthalenesulfonic acid and phenylbenzimidazolesulfonic acid, and the modification aid can be any one or more of the above.

[0040] Among them, the mass ratio of the modified auxiliary agent to the theoretical amount of magnesium hydroxide in the magnesium hydroxide reactant slurry is controlled to be (0.1-1.0): 100, such as 0.1: 100, 0.2: 100, 0.3: 100, 0.4: 100, 0.5: 100, 0.6: 100, 0.7: 100, 0.8: 100, 0.9: 100, 1.0: 100, etc., but is not limited to the above ratio values, and other unlisted values ​​within the numerical range are also applicable.

[0041] In a preferred embodiment, the mass ratio of the modification aid to magnesium hydroxide is (0.3-0.7):100; wherein the modification aid is selected from at least one of methanesulfonic acid, ethanesulfonic acid and trifluoromethanesulfonic acid, and the amount and type of the modification aid are regulated to further improve the modification effect, which is beneficial to further improve the flexibility and adhesion of the coating.

[0042] In some embodiments, during the process of preparing the modified slurry, the magnesium hydroxide reactant slurry and the modification aid are mixed and stirred for 1 h-2 h (such as 1.0 h, 1.5 h, 2.0 h, etc.) to uniformly mix the modification aid and the magnesium hydroxide.

[0043] S3, washing and drying

[0044] The modified slurry is washed and then dried to obtain a modified magnesium hydroxide product.

[0045] In some embodiments, the modified slurry can be washed with water, filtered and washed with deionized water until the pH value is 7-10 (such as 7.0, 8.0, 9.0, 10.0, etc.), and then spray-dried.

[0046] The embodiment of the present invention provides a modified magnesium hydroxide, comprising magnesium hydroxide and a modification aid, wherein the mass ratio of the modification aid to the magnesium hydroxide is (0.1-1.0):100; wherein the modification aid is selected from at least one of methanesulfonic acid, ethanesulfonic acid, trifluoromethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, naphthalenesulfonic acid and phenylbenzimidazole sulfonic acid.

[0047] It should be noted that by introducing a specific amount of modification aid into magnesium hydroxide, the impurity metal cations of magnesium hydroxide can be effectively removed to prevent PVDF from deteriorating and discoloring. If the amount of modification aid added is less than 0.1%, the pH effect cannot be improved, resulting in poor flexibility, adhesion and tolerance of the electrode after coating. If the amount of modification aid added is higher than 1%, it will cause serious agglomeration of powder and make it impossible to achieve uniform coating.

[0048] An embodiment of the present invention further provides a lithium battery edge-coated pole piece, comprising a pole piece substrate and a coating located on at least one side of the pole piece substrate, wherein the coating comprises the modified magnesium hydroxide provided by the embodiment of the present invention, and may also comprise PVDF, NMP, etc.

[0049] It should be noted that the specific method of using the magnesium hydroxide powder provided in the embodiment of the present invention for coating the edge of the pole piece is a conventional technical means, and those skilled in the art can adaptively select and adjust it according to actual needs. For example, after the magnesium hydroxide powder prepared in the embodiment of the present invention is prepared into a slurry (without modifying the edge coating slurry formula), it can be coated using conventional coating means. In addition, the magnesium hydroxide powder prepared in the embodiment of the present invention can also be used in combination with other substances that can be used for pole pieces, and all solutions that can be known to those skilled in the art within a reasonable range are applicable.

[0050] An embodiment of the present invention further provides a lithium battery, comprising the above-mentioned lithium-ion battery edge-coated electrode, and may further include a diaphragm, an electrolyte, and the like.

[0051] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0052] Example 1

[0053] This embodiment provides a method for preparing modified magnesium hydroxide, the steps are as follows:

[0054] (1) 1T of magnesium chloride hexahydrate and 2.4T of pure water were added to a reactor and preheated to 60°C with continuous stirring; then a high-purity alkali solution (515L of a sodium hydroxide aqueous solution with a concentration of 19.1 mol / L) preheated to 60°C was added dropwise to the magnesium salt solution, the temperature was maintained at 60°C, stirring was continued for 2h, and the reaction was aged at room temperature for 10h to obtain a first magnesium hydroxide reaction product (theoretical amount of magnesium hydroxide was 0.609T).

[0055] (2) Add 0.609 kg of benzenesulfonic acid to the first magnesium hydroxide reaction body slurry after the aging reaction and stir for 1 hour. Note: The mass ratio of the modification aid to magnesium hydroxide in this embodiment is 0.1:100.

[0056] (3) filtering and washing the modified slurry with deionized water until the pH value is 8; spray drying the modified magnesium hydroxide reaction product to obtain modified magnesium hydroxide powder.

[0057] In this embodiment, the prepared magnesium hydroxide is a white powder with a purity of 99.90% and a D50 of 0.7 μm. The modified magnesium hydroxide is mixed with PVDF and NMP in a mass ratio of 120:20:140 at a speed of 1000 rpm for 4 hours without discoloration or gelation. The SEM photo of the modified magnesium hydroxide prepared in this embodiment is shown in Figure 1 shown.

[0058] Example 2

[0059] The difference between this embodiment and embodiment 1 is that the modification aid used in step (2) is 1.218 kg of methanesulfonic acid to obtain modified magnesium hydroxide.

[0060] In this embodiment, the prepared magnesium hydroxide is a white powder with a purity of 99.89%, a D50 of 0.7 μm, a mass ratio of magnesium hydroxide to PVDF and NMP of 120:20:140, a rotation speed of 1000 rpm, and no color change or gelation after 4 hours of mixing.

[0061] Example 3

[0062] The difference between this embodiment and embodiment 1 is that the modification aid used in step (2) is 1.827 kg of ethanesulfonic acid to obtain modified magnesium hydroxide.

[0063] In this embodiment, the prepared magnesium hydroxide is a white powder with a purity of 99.82%, a D50 of 0.7 μm, a mass ratio of magnesium hydroxide to PVDF and NMP of 120:20:140, a rotation speed of 1000 rpm, and no color change or gelation after 4 hours of mixing.

[0064] Example 4

[0065] The difference between this embodiment and embodiment 1 is that the modification aid used in step (2) is 2.436 kg of trifluoromethanesulfonic acid to obtain modified magnesium hydroxide.

[0066] In this embodiment, the prepared magnesium hydroxide is a white powder with a purity of 99.90%, a D50 of 0.7 μm, a mass ratio of magnesium hydroxide to PVDF and NMP of 120:20:140, a rotation speed of 1000 rpm, and no color change or gelation after 4 hours of mixing.

[0067] Example 5

[0068] The difference between this embodiment and embodiment 1 is that the modification aid used in step (2) is 3.045 kg of p-toluenesulfonic acid to obtain modified magnesium hydroxide.

[0069] In this embodiment, the prepared magnesium hydroxide is a white powder with a purity of 99.91%, a D50 of 0.7 μm, a mass ratio of magnesium hydroxide to PVDF and NMP of 120:20:140, a rotation speed of 1000 rpm, and no color change or gelation after 4 hours of mixing.

[0070] Example 6

[0071] The difference between this embodiment and embodiment 1 is that the modification aid used in step (2) is 3.654 kg of naphthalenesulfonic acid to obtain modified magnesium hydroxide.

[0072] In this embodiment, the prepared magnesium hydroxide is a white powder with a purity of 99.89%, a D50 of 0.7 μm, a mass ratio of magnesium hydroxide to PVDF and NMP of 120:20:140, a rotation speed of 1000 rpm, and no color change or gelation after 4 hours of mixing.

[0073] Example 7

[0074] The difference between this embodiment and embodiment 1 is that the modification aid used in step (2) is 6.09 kg of phenylbenzimidazole sulfonic acid to obtain modified magnesium hydroxide.

[0075] In this embodiment, the prepared magnesium hydroxide is a white powder with a purity of 99.87%, a D50 of 0.7 μm, a mass ratio of magnesium hydroxide to PVDF and NMP of 120:20:140, a rotation speed of 1000 rpm, and no color change or gelation after 4 hours of mixing.

[0076] Example 8

[0077] The difference between this embodiment and embodiment 1 is that the preheating temperature in step (1) is 70° C. to obtain modified magnesium hydroxide.

[0078] In this embodiment, the prepared magnesium hydroxide is a white powder with a purity of 99.89%, a D50 of 0.91 μm, a mass ratio of magnesium hydroxide to PVDF and NMP of 120:20:140, a rotation speed of 1000 rpm, and no color change or gelation after 4 hours of mixing.

[0079] Example 9

[0080] The difference between this embodiment and embodiment 1 is that the preheating temperature in step (1) is 80° C. to obtain modified magnesium hydroxide.

[0081] In this embodiment, the prepared magnesium hydroxide is a white powder with a purity of 99.89%, a D50 of 1.12 μm, a mass ratio of magnesium hydroxide to PVDF and NMP of 120:20:140, a rotation speed of 1000 rpm, and no color change or gelation after 4 hours of mixing.

[0082] Example 10

[0083] The difference between this embodiment and embodiment 1 is that the preheating temperature in step (1) is 90° C. to obtain modified magnesium hydroxide.

[0084] In this embodiment, the prepared magnesium hydroxide is a white powder with a purity of 99.89%, a D50 of 1.34 μm, a mass ratio of magnesium hydroxide to PVDF and NMP of 120:20:140, a rotation speed of 1000 rpm, and no color change or gelation after 4 hours of mixing.

[0085] Embodiment 11

[0086] The difference between this embodiment and embodiment 1 is that the modification aid is replaced by an equal amount of methanesulfonic acid instead of benzenesulfonic acid.

[0087] In this embodiment, the prepared magnesium hydroxide is a white powder with a purity of 99.90% and a D50 of 0.7 μm. The modified magnesium hydroxide is mixed with PVDF and NMP in a mass ratio of 120:20:140 at a rotation speed of 1000 rpm. After 4 hours of mixing, there is no discoloration or gelation.

[0088] Example 12

[0089] The difference between this embodiment and embodiment 1 is that the modification aid is replaced by an equal amount of ethanesulfonic acid instead of benzenesulfonic acid.

[0090] In this embodiment, the prepared magnesium hydroxide is a white powder with a purity of 99.90% and a D50 of 0.7 μm. The modified magnesium hydroxide is mixed with PVDF and NMP in a mass ratio of 120:20:140 at a rotation speed of 1000 rpm. After 4 hours of mixing, there is no discoloration or gelation.

[0091] Comparative Example 1

[0092] The difference between this comparative example and Example 1 is that no modifying agent is added in step (2).

[0093] In this comparative example, the prepared magnesium hydroxide is a white powder with a purity of 99.89% and a D50 of 0.7 μm. The mass ratio of magnesium hydroxide to PVDF and NMP is 120:20:140. The rotation speed is 1000 rpm, and the slurry turns pink after 4 hours of mixing.

[0094] Comparative Example 2

[0095] The difference between this comparative example and Example 1 is that the modification aid used in step (2) is 0.5 kg of benzenesulfonic acid.

[0096] In this comparative example, the prepared magnesium hydroxide is a white powder with a purity of 99.89% and a D50 of 0.7 μm. The mass ratio of magnesium hydroxide to PVDF and NMP is 120:20:140. The rotation speed is 1000 rpm, and the slurry turns pink after 4 hours of mixing.

[0097] Comparative Example 3

[0098] The difference between this comparative example and Example 1 is that the modification aid used in step (2) is 12 kg of benzenesulfonic acid.

[0099] In this comparative example, the prepared magnesium hydroxide is a white powder with a purity of 99.89%, a D50 of 30 μm, a mass ratio of magnesium hydroxide to PVDF and NMP of 120:20:140, a rotation speed of 1000 rpm, and the slurry does not change color or gel after 4 hours of mixing. The measured slurry particle size is greater than 30 μm, the powder agglomerates and cannot be opened, and cannot be coated and used.

[0100] Comparative Example 4

[0101] The difference between this comparative example and Example 1 is that the preheating temperature in step (1) is 50° C. to obtain modified magnesium hydroxide.

[0102] In this comparative example, the prepared magnesium hydroxide is a white powder with a purity of 99.89%, a D50 of 3.416 μm, and a mass ratio of magnesium hydroxide to PVDF and NMP of 120:20:140. The rotation speed is 1000 rpm, and there is no discoloration or gelation after 4 hours of mixing. The SEM photo of the magnesium hydroxide prepared in this comparative example is shown in Figure 2 As shown, the low preheating temperature leads to abnormally uneven morphology and cannot be used for coating.

[0103] The performance test results of the modified magnesium hydroxide obtained in the embodiments and comparative examples are summarized as shown in Table 1:

[0104] Table 1 Performance test results of modified magnesium hydroxide obtained in Examples and Comparative Examples

[0105]

[0106]

[0107] It can be seen from Table 1 that the modified magnesium hydroxide prepared in the embodiment of the present invention can effectively prevent the PVDF slurry from discoloring and gelling, and the modified magnesium hydroxide coated electrode can make the coating have good flexibility and adhesion, can reduce the risk of coating shedding caused by factors such as vibration during the use of the electrode, and has good electrolyte tolerance.

[0108] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A modified magnesium hydroxide, characterized in that It comprises magnesium hydroxide and a modification aid, wherein the mass ratio of the modification aid to the magnesium hydroxide is (0.1-1.0):100; Wherein, the modification aid is selected from at least one of methanesulfonic acid, ethanesulfonic acid, trifluoromethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, naphthalenesulfonic acid and phenylbenzimidazolesulfonic acid.

2. The modified magnesium hydroxide according to claim 1, characterized in that The mass ratio of the modification aid to magnesium hydroxide is (0.3-0.7):100; Wherein, the modification aid is selected from at least one of methanesulfonic acid, ethanesulfonic acid and trifluoromethanesulfonic acid.

3. A method for preparing the modified magnesium hydroxide according to claim 1 or 2, characterized in that: include: The magnesium hydroxide is modified by using the modification aid.

4. The preparation method according to claim 3, characterized in that: include: The magnesium salt solution and the alkali solution are reacted and aged to obtain a magnesium hydroxide reaction body slurry; The magnesium hydroxide reaction body slurry and the modification aid are mixed and stirred to obtain a modified slurry; wherein the mass ratio of the modification aid to the theoretical amount of magnesium hydroxide in the magnesium hydroxide reaction body slurry is controlled to be (0.1-1.0):100; The modified pulp is washed and then dried.

5. The preparation method according to claim 4, characterized in that: The process of preparing the magnesium hydroxide reaction body slurry includes: first preheating the magnesium salt solution to 60°C-100°C, dropwise adding the alkali solution at a temperature of 60°C-100°C into the magnesium salt solution, reacting at 60°C-100°C for 1h-10h, and then aging the reaction at 15°C-35°C for 2h-24h.

6. The preparation method according to claim 4 or 5, characterized in that: The magnesium salt solution is obtained by mixing a soluble magnesium salt and water, and the soluble magnesium salt is selected from at least one of magnesium chloride, magnesium carbonate, magnesium nitrate and magnesium sulfate; And / or, the alkali solution is selected from at least one of a sodium hydroxide solution, an ammonia solution and a potassium hydroxide solution.

7. The preparation method according to claim 4, characterized in that: During the preparation of the modified slurry, the magnesium hydroxide reaction body slurry and the modified auxiliary agent are mixed and stirred for 1 h to 2 h.

8. The preparation method according to claim 4, characterized in that: The modified slurry is washed with water until the pH value is 7-10, and then spray-dried.

9. A lithium battery edge-coated electrode, characterized in that: It comprises a pole piece substrate and a coating located on at least one side of the pole piece substrate, wherein the coating comprises the modified magnesium hydroxide described in any one of claims 1-2 or the modified magnesium hydroxide prepared by the preparation method described in any one of claims 3-8.

10. A lithium battery, characterized in that: Including the lithium-ion battery edge-coated electrode as described in claim 9.

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