Polyether phosphate dispersing agent as well as preparation method and application thereof

Abstract

The invention provides a polyether phosphate dispersing agent as well as a preparation method and application thereof. The polyether phosphate dispersing agent has a structure as shown in the specification. The polyether phosphate dispersing agent provided by the invention is used for dispersing the battery positive electrode slurry, so that the viscosity of the battery positive electrode slurry can be effectively reduced, the flowability of the positive electrode slurry is improved, the stability of the positive electrode slurry is enhanced, the slurry is effectively prevented from settling and agglomerating, and the production efficiency and the use efficiency of the battery slurry are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of dispersants, and relates to a polyether phosphate dispersant, a preparation method and application thereof, and specifically relates to a polyether phosphate dispersant, a preparation method and application thereof in battery positive electrode slurry. Background Art

[0002] As a new energy technology, lithium-ion batteries are widely used due to their advantages such as lightness and portability. With the in-depth study of lithium-ion batteries, their characteristics such as high voltage, light weight and high energy density are gradually being recognized and utilized. Lithium-ion batteries can be charged quickly and are widely used in various fields such as automobiles, mobile phones, computers, etc.

[0003] The downstream of lithium-ion batteries can be divided into three major areas: power, consumption and energy storage. Power lithium-ion batteries are mainly used in electric vehicles, electric light vehicles, power tools, etc.; consumer lithium-ion batteries are used in mobile phones, laptops, Bluetooth headsets, wearable devices, etc.; energy storage lithium-ion batteries provide energy storage support for communication base stations, off-grid power stations, microgrids, rail transit, etc.

[0004] The dispersion and uniformity of the positive electrode slurry of lithium-ion batteries directly affect the movement of lithium ions between the two poles of the battery. Therefore, the mixing and dispersion of the slurries of various pole materials in the production of lithium-ion batteries is crucial. The quality of slurry dispersion directly affects the quality of subsequent lithium-ion battery production and the performance of its products. With the continuous advancement of lithium-ion battery materials, the particle size of raw materials is getting smaller and smaller, and the energy density is getting higher and higher. Although this improves the performance of lithium-ion batteries, it is also very easy to form secondary agglomerates when preparing positive electrode slurry, resulting in a continuous increase in slurry viscosity and increasing the difficulty of the mixing and dispersion process.

[0005] Therefore, it is desirable in the art to develop a dispersant for lithium ion battery positive electrode slurry that can improve the dispersion effect of the slurry. Summary of the invention

[0006] In view of the shortcomings of the prior art, namely, the problems that positive electrode slurry of lithium-ion batteries is difficult to disperse, has poor fluidity, and is easy to agglomerate and become sticky after dispersion, the object of the present invention is to provide a polyether phosphate dispersant and a preparation method and application thereof, and specifically to provide a polyether phosphate dispersant and a preparation method thereof and application thereof in positive electrode slurry of batteries.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a polyether phosphate dispersant, wherein the polyether phosphate dispersant has a structure as shown in the following formula (I):

[0009]

[0010] wherein R is any one of -PO3H2, a C1-C18 (e.g., C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17 or C18) linear or branched alkyl group, an unsaturated group containing C=C, a benzene ring or a phenol group;

[0011] m is an integer from 0 to 300, for example 0, 2, 4, 6, 8, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 120, 140, 160, 180, 200, 220, 240, 260, 280, 300, etc., as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the said range.

[0012] n is an integer from 1 to 300, for example 1, 2, 4, 6, 8, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 120, 140, 160, 180, 200, 220, 240, 260, 280, 300, etc., as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the said range.

[0013] The polyether phosphate dispersant provided by the present invention is used to disperse the positive electrode slurry of the battery, which can effectively reduce the viscosity of the positive electrode slurry of the battery, increase the fluidity of the positive electrode slurry, enhance the stability of the positive electrode slurry, effectively prevent the slurry from settling and agglomerating, and improve the production efficiency and use efficiency of the battery slurry. Compared with the prior art, the polyphosphate dispersant provided by the present invention has the following advantages: 1) Rapid viscosity reduction, the polyether phosphate dispersant provided by the present invention has multiple phosphate anchoring groups, which can quickly wet the powders such as lithium iron phosphate in the positive electrode slurry; 2) Good anti-settling effect, the polyether phosphate dispersant provided by the present invention contains a polyether chain as a solvation chain, and has a strong anti-settling effect; 3) Good compatibility, the polyether phosphate dispersant provided by the present invention contains a hydrocarbon group or a propylene oxide chain segment, and has good compatibility with the binder resin in the slurry.

[0014] Preferably, said R is -PO3H2.

[0015] Preferably, m is an integer from 0 to 100.

[0016] Preferably, n is an integer of 1-50.

[0017] Preferably, the polyether phosphate dispersant is synthesized by esterification and hydrolysis reaction of polyether and phosphorylation agent.

[0018] Preferably, the polyether has a structure as shown in the following formula (II):

[0019]

[0020] Among them, R 1 Any one of -H, a C1-C18 (e.g., C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17 or C18) straight chain or branched chain alkyl, an unsaturated group containing C=C, a benzene ring or a phenol group.

[0021] m is an integer from 0 to 300, for example 0, 2, 4, 6, 8, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 120, 140, 160, 180, 200, 220, 240, 260, 280, 300, etc., as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the said range.

[0022] n is an integer from 1 to 300, for example 1, 2, 4, 6, 8, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 120, 140, 160, 180, 200, 220, 240, 260, 280, 300, etc., as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the said range.

[0023] Preferably, the phosphorylation agent includes any one of phosphorus pentoxide, polyphosphoric acid, phosphorus oxychloride, phosphoric acid, or a combination of at least two thereof.

[0024] Preferably, the molar ratio of the polyether to the phosphorylating agent is (1-5):1, for example 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, etc., as well as specific ratios between the above ratios. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific ratios included in the range.

[0025] In a second aspect, the present invention provides a method for preparing the polyether phosphate dispersant as described in the first aspect, the preparation method comprising the following steps:

[0026] The polyether and the phosphorylation agent are mixed to carry out an esterification reaction, and then deionized water is added to carry out a hydrolysis reaction to obtain the polyether phosphate dispersant.

[0027] Preferably, the mixing specifically comprises: adding the phosphorylation reagent into the polyether in 1 to 5 times (eg, 1 time, 2 times, 3 times, 4 times or 5 times).

[0028] Preferably, the temperature of the esterification reaction is 50-120°C, for example 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, etc., as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range. The time of the esterification reaction is 2-8h, for example 2h, 3h, 4h, 5h, 6h, 7h, 8h, etc., as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0029] Preferably, the amount of deionized water added is 0.5% to 5% of the total mass of the polyether and the phosphorylation reagent, for example 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, etc., as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0030] Preferably, the temperature of the hydrolysis reaction is 50-100°C, for example 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, etc., as well as specific point values ​​between the above-mentioned point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range. The time of the hydrolysis reaction is 2-10h, for example 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, etc., as well as specific point values ​​between the above-mentioned point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0031] Preferably, the step of drying the polyether is further included before the mixing.

[0032] Preferably, the drying of the polyether specifically comprises:

[0033] The polyether is put into a reaction kettle, and an inert gas is introduced for 10 to 60 minutes (for example, 10 minutes, 20 minutes, 30 minutes, 40 minutes, 50 minutes, 60 minutes, etc., and specific values ​​between the above points. Due to space limitations and for simplicity, the present invention no longer exhaustively lists the specific values ​​included in the range), and the heating device is turned on to raise the temperature to 60 to 120° C. (for example, 60° C., 70° C., 80° C., 90° C., 100° C., 110° C., 120° C., etc., and specific values ​​between the above points. Due to space limitations and for simplicity, the present invention no longer exhaustively lists the specific values ​​included in the range). The temperature is kept warm for 1 to 5 hours (for example, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, etc., as well as specific point values ​​between the above point values. Due to space limitations and for the sake of brevity, the present invention no longer lists the specific point values ​​included in the range) until the water content of the system is reduced to below 0.2% (for example, 0.2%, 0.18%, 0.15%, 0.1%, etc., as well as specific point values ​​between the above point values. Due to space limitations and for the sake of brevity, the present invention no longer lists the specific point values ​​included in the range).

[0034] In a third aspect, the present invention provides a use of the polyether phosphate dispersant as described in the first aspect in a slurry.

[0035] Preferably, the slurry comprises battery positive electrode slurry.

[0036] Preferably, the slurry comprises lithium-ion battery positive electrode slurry.

[0037] Compared with the prior art, the present invention has at least the following beneficial effects:

[0038] 1) The polyether phosphate dispersant provided by the present invention has multiple phosphate anchoring groups, which can quickly wet the lithium iron phosphate powder and the like in the positive electrode slurry, and is used to quickly reduce the viscosity of the positive electrode slurry;

[0039] 2) The polyether phosphate dispersant provided by the present invention contains a polyether chain as a solvation chain, has a strong anti-settling effect, and has a good anti-settling effect when used for positive electrode slurry;

[0040] 3) The polyether phosphate dispersant provided by the present invention contains hydrocarbon groups or propylene oxide chain segments, is used in positive electrode slurry, and has good compatibility with the binder resin in the slurry. DETAILED DESCRIPTION

[0041] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0042] Example 1

[0043] In this embodiment, a polyether phosphate dispersant is provided, and the polyether phosphate dispersant has the following structure:

[0044]

[0045] The preparation method comprises the following steps:

[0046] S1: Put polyether (molecular weight 600) into a reactor, introduce inert gas for 30 minutes, turn on the heating device, raise the temperature to 105°C and keep it for 1 hour until the moisture content of the reaction system drops below 0.2%;

[0047] S2: Adjust the temperature of the reactor to 30°C, then add the phosphorylation reagent three times every 30 minutes, control the reaction temperature to 80°C for 4 hours, and then the reaction is completed;

[0048] S3: After the esterification reaction is completed, the temperature is lowered to 60° C. and deionized water (the amount added is 1.0% of the total mass of the polyether and the phosphorylation reagent) is slowly added dropwise. The reaction is controlled at 60° C. for 2 hours. The reaction is completed to obtain the polyether phosphate dispersant.

[0049] Among them, the polyether has the following structure:

[0050]

[0051] The phosphorylation agent is phosphorus pentoxide; the molar ratio of the polyether to the phosphorylation agent is 2.15:1.

[0052] Example 2

[0053] In this embodiment, a polyether phosphate dispersant is provided, and the polyether phosphate dispersant has the following structure:

[0054]

[0055] The preparation method comprises the following steps:

[0056] S1: Put polyether (molecular weight 1200) into a reactor, introduce inert gas for 30 min, turn on the heating device, raise the temperature to 105°C and keep it for 1 h until the moisture content of the reaction system drops below 0.2%;

[0057] S2: Adjust the temperature of the reactor to 80°C, then add the phosphorylation reagent three times every 30 minutes, control the reaction temperature to 80°C for 6 hours, and then the reaction is completed;

[0058] S3: After the esterification reaction is completed, the temperature is lowered to 70° C. and deionized water (the amount added is 0.5% of the total mass of the polyether and the phosphorylation reagent) is slowly added dropwise. The reaction is controlled at 70° C. for 2 hours. The reaction is completed to obtain the polyether phosphate dispersant.

[0059] Among them, the polyether has the following structure:

[0060]

[0061] The phosphorylation agent is phosphorus oxychloride; the molar ratio of the polyether to the phosphorylation agent is 2.15:1.

[0062] Example 3

[0063] In this embodiment, a polyether phosphate dispersant is provided, and the polyether phosphate dispersant has the following structure:

[0064]

[0065] The preparation method comprises the following steps:

[0066] S1: Put polyether (molecular weight 2000) into a reactor, introduce inert gas for 30 min, turn on the heating device, raise the temperature to 105°C and keep it for 1 h until the moisture content of the reaction system drops below 0.2%;

[0067] S2: Adjust the temperature of the reactor to 60°C, then add the phosphorylation reagent once, control the reaction temperature to 90°C for 5 hours, and the reaction is completed;

[0068] S3: After the esterification reaction is completed, the temperature is lowered to 90° C. and deionized water (the amount added is 1.0% of the total mass of the polyether and the phosphorylation reagent) is slowly added dropwise. The reaction is controlled at 90° C. for 4 hours. The reaction is completed to obtain the polyether phosphate dispersant.

[0069] Among them, the polyether has the following structure:

[0070]

[0071] The phosphorylation agent is phosphoric acid; the molar ratio of the polyether to the phosphorylation agent is 2.05:1.

[0072] Example 4

[0073] In this embodiment, a polyether phosphate dispersant is provided, and the polyether phosphate dispersant has the following structure:

[0074]

[0075] The preparation method comprises the following steps:

[0076] S1: Put polyether (molecular weight 2000) into a reactor, introduce inert gas for 30 min, turn on the heating device, raise the temperature to 105°C and keep it for 1 h until the moisture content of the reaction system drops below 0.2%;

[0077] S2: Adjust the temperature of the reactor to 60°C, then add the phosphorylation reagent once, control the reaction temperature to 90°C for 5 hours, and the reaction is completed;

[0078] S3: After the esterification reaction is completed, the temperature is lowered to 80° C. and deionized water (the amount added is 0.5% of the total mass of the polyether and the phosphorylation reagent) is slowly added dropwise. The reaction is controlled at 80° C. for 2 hours. The reaction is completed to obtain the polyether phosphate dispersant.

[0079] Among them, the polyether has the following structure:

[0080]

[0081] The phosphorylation agent is phosphorus pentoxide; the molar ratio of the polyether to the phosphorylation agent is 2.15:1.

[0082] Comparative Example 1

[0083] The only difference between this comparative example and Example 1 is that the polyether is replaced by an equal molar amount of PEG-600.

[0084] Comparative Example 2

[0085] The only difference between this comparative example and Example 1 is that the phosphorylation reagent is replaced by an equimolar amount of adipic acid, and p-toluenesulfonic acid is used as a catalyst for esterification to synthesize a polyether ester dispersant.

[0086] Comparative Example 3

[0087] In this comparative example, a conventional dispersant is provided: a commercially available polyether-modified styrene maleic anhydride dispersant BYK-190.

[0088] Application Example 1

[0089] In this application example, a lithium-ion battery positive electrode slurry is provided, which is prepared using the polyether phosphate provided in Example 1 as a dispersant, and the solid content is prepared according to the following mass ratio: PVDF:SP:LFP:dispersant = 2:1.7:96:0.3. NMP is used as a dispersion medium to prepare a positive electrode slurry with a solid content of 60%, and the viscosity change and stability are examined.

[0090] Application Examples 2 to 4, Comparative Application Examples 1 to 3

[0091] The difference between Application Examples 2 to 4 and Comparative Application Examples 1 to 3 and Application Example 1 is that the polyether phosphate dispersant provided in Example 1 is replaced by the dispersants provided in Examples 2 to 4 and Comparative Examples 1 to 3 in equal weights.

[0092] Comparative Application Example 4

[0093] The only difference between this comparative application example and application example 1 is that no polyether phosphate dispersant is added.

[0094] The performance test of the lithium-ion battery positive electrode slurry provided in the corresponding use case and comparative application example is carried out as follows:

[0095] (1) Viscosity: The viscosity of the mixture was tested after being left to stand for 0 min, 10 min, 1 h, 2 h, 3 h, 24 h, and after being stirred for 1 min after 24 h.

[0096] (2) Storage stability: After the positive electrode slurry is prepared, it is placed in a 50°C oven for heat storage and its sedimentation is observed. The evaluation is graded from 1 to 5, with grade 1 being the best and grade 5 being the worst.

[0097] The viscosity (mpa·s) test results are shown in Table 1:

[0098] Table 1

[0099]

[0100]

[0101] The storage stability test results are shown in Table 2:

[0102] Table 2

[0103] immediately 1h 3h 10h 1d 3d 5d Application Example 1 1 1 1 1 1 2 2 Application Example 2 1 1 1 1 1 1 1 Application Example 3 1 1 1 1 2 2 2 Application Example 4 1 1 1 1 1 2 2 Comparative application example 1 1 1 3 4 5 5 5 Comparative Application Example 2 1 3 3 5 5 5 5 Comparative Application Example 3 1 3 5 5 5 5 5 Comparative Application Example 4 2 5 Sedimentation and stratification Sedimentation and stratification Sedimentation and stratification Sedimentation and stratification Sedimentation and stratification

[0104] It can be seen from Tables 1 and 2 that the polyether phosphate dispersant provided by the embodiment of the present invention is used to disperse the positive electrode slurry of a lithium-ion battery, which can reduce the viscosity of the positive electrode slurry, increase the fluidity of the positive electrode slurry, enhance the stability of the positive electrode slurry, and effectively prevent the slurry from settling and agglomerating, thereby improving the production efficiency and use efficiency of the battery slurry.

[0105] Compared with Application Example 1, the viscosity of the positive electrode slurry provided in Comparative Application Example 1 is significantly increased, and the storage stability is average; the viscosity of the positive electrode slurry provided in Comparative Application Example 2 is significantly increased, and the storage stability is poor; the storage stability of the positive electrode slurry provided in Comparative Application Example 3 is extremely poor; the viscosity of the positive electrode slurry provided in Comparative Application Example 4 is greatly increased, and the storage stability is extremely poor.

[0106] The applicant declares that the present invention uses the above-mentioned embodiments to illustrate the polyether phosphate dispersant and its preparation method and application, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A polyether phosphate dispersant, characterized in that: The polyether phosphate dispersant has a structure shown in the following formula (I): Wherein, R is any one of -PO3H2, a C1-C18 straight-chain or branched alkyl group, an unsaturated group containing C=C, a benzene ring or a phenol group; m is an integer from 0 to 300; n is an integer from 1 to 300.

2. The polyether phosphate dispersant according to claim 1, characterized in that The R is -PO3H2.

3. The polyether phosphate dispersant according to claim 1 or 2, characterized in that The m is an integer from 0 to 100; Preferably, n is an integer of 1-50.

4. The polyether phosphate dispersant according to any one of claims 1 to 3, characterized in that The polyether phosphate dispersant is synthesized by esterification and hydrolysis reaction of polyether and phosphorylation reagent; Preferably, the polyether has a structure as shown in the following formula (II): Among them, R 1 Any one of -H, a C1-C18 straight or branched alkyl group, an unsaturated group containing C=C, a benzene ring or a phenol group; m is an integer from 0 to 300; n is an integer from 1 to 300; Preferably, the phosphorylation agent comprises any one of phosphorus pentoxide, polyphosphoric acid, phosphorus oxychloride, phosphoric acid, or a combination of at least two thereof; Preferably, the molar ratio of the polyether to the phosphorylation agent is (1-5):

1.

5. A method for preparing a polyether phosphate dispersant as claimed in any one of claims 1 to 4, characterized in that: The preparation method comprises the following steps: The polyether and the phosphorylation agent are mixed to carry out an esterification reaction, and then deionized water is added to carry out a hydrolysis reaction to obtain the polyether phosphate dispersant.

6. The preparation method according to claim 5, characterized in that: The mixing specifically comprises: adding the phosphorylation reagent into the polyether in 1 to 5 times; Preferably, the temperature of the esterification reaction is 50-120° C., and the time of the esterification reaction is 2-8 hours.

7. The preparation method according to claim 5 or 6, characterized in that: The added amount of the deionized water is 0.5% to 5% of the total mass of the polyether and the phosphorylation reagent.

8. The preparation method according to any one of claims 5 to 7, characterized in that: The temperature of the hydrolysis reaction is 50-100° C., and the time of the hydrolysis reaction is 2-10 hours.

9. The preparation method according to any one of claims 5 to 8, characterized in that: The step of drying the polyether is also included before the mixing; Preferably, the drying of the polyether specifically comprises: Put the polyether into the reaction kettle, introduce inert gas for 10 to 60 minutes, turn on the heating device, raise the temperature to 60 to 120°C and keep it warm for 1 to 5 hours until the water content of the system is reduced to below 0.2%.

10. Use of the polyether phosphate dispersant according to any one of claims 1 to 4 in slurry; Preferably, the slurry comprises battery positive electrode slurry; Preferably, the slurry comprises lithium-ion battery positive electrode slurry.

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