Bio-based lithium battery negative electrode adhesive as well as preparation method and application thereof

Abstract

The invention provides a bio-based lithium battery negative electrode adhesive as well as a preparation method and application thereof, and belongs to the technical field of high polymer materials for batteries. The preparation raw materials of the bio-based lithium battery negative electrode adhesive comprise diisocyanate, a macromolecular chain extender, a micromolecular chain extender, an unsaturated end-capping reagent, an organic solvent, water, an initiator and an amine neutralizer, wherein the macromolecular chain extender is at least one of bio-based polyester polyol or polyether polyol; the micromolecular chain extender comprises bis (hydroxymethyl) propionic acid. The bio-based lithium battery negative electrode adhesive material disclosed by the invention has very strong solvent-resistant and corrosion-resistant characteristics, can be prevented from being dissolved after being soaked in a strong electrolyte for a long time, and is controllable in swelling rate.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer materials for batteries and relates to a bio-based lithium battery negative electrode adhesive and a preparation method and application thereof. Background Art

[0002] The increasing popularity of electric vehicles and portable devices has placed higher demands on the fast-charging performance of lithium batteries. During fast charging, the rapid insertion and extraction of lithium ions can cause volume changes in the electrode material, which in turn affects the stability and life of the battery.

[0003] Under fast-charging conditions, electrode materials and separators must possess excellent chemical stability and mechanical strength to prevent structural damage and performance degradation due to swelling. The swelling properties of the binder also affect the structural stability of the electrode. By testing the swelling rate of the binder in the electrolyte, high-performance binders suitable for fast-charging batteries can be screened.

[0004] As performance requirements continue to increase, existing negative electrode binders cannot meet the higher charge and discharge performance requirements. At the same time, the new era has also put forward more environmental protection requirements. The development of primary materials derived from renewable bio-based materials is a research focus in this field. Summary of the Invention

[0005] To address the shortcomings of the prior art, the present invention provides a bio-based lithium battery negative electrode binder, its preparation method, and its application. The bio-based lithium battery negative electrode binder material of the present invention exhibits strong solvent and corrosion resistance, can withstand long-term immersion in strong electrolytes without dissolving, and has a controllable swelling rate.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] On the one hand, the present invention provides a bio-based lithium battery negative electrode adhesive, wherein the raw materials for preparing the bio-based lithium battery negative electrode adhesive include diisocyanate, a macromolecular chain extender, a small molecule chain extender, an unsaturated end capping agent, an organic solvent, water, an initiator, and an amine neutralizer, wherein the macromolecular chain extender is at least one of a bio-based polyester polyol or a polyether polyol, and the small molecule chain extender includes bis(hydroxymethyl)propionic acid.

[0008] In the present invention, the bio-based lithium battery negative electrode adhesive material prepared using the raw materials prepared as described above has strong solvent resistance and corrosion resistance, can be immersed in a strong electrolyte for a long time without dissolving, and the swelling rate is controllable.

[0009] Preferably, the diisocyanate is a bio-based diisocyanate.

[0010] Preferably, the bio-based diisocyanate is selected from any one or a combination of at least two of pentamethylene diisocyanate (PDI), lysine diisocyanate (LDI) or 2,5-furan diisocyanate.

[0011] Preferably, the macromolecular chain extender is selected from any one or a combination of at least two of polytrimethylene ether glycol (PO3G), polycaprolactone (PCL), castor oil modified polyol or polytetramethylene ether glycol (PTMEG).

[0012] Preferably, the number average molecular weight of the macromolecular chain extender is 1000-3000, for example, 1000, 1200, 1500, 1800, 2000, 2300, 2500, 2800 or 3000, preferably 2000. In the present invention, if the number average molecular weight of the macromolecular chain extender is less than 1000, the molecular weight of the final prepared material is too low and the strength is poor, and it will be dissolved when immersed in the electrolyte. If the number average molecular weight of the macromolecular chain extender is greater than 3000, the strength of the material is insufficient.

[0013] Preferably, the unsaturated end-capping agent is selected from any one of hydroxyethyl methacrylate, hydroxyethyl acrylate, or hydroxypropyl acrylate, or a combination of at least two thereof.

[0014] Preferably, the organic solvent is selected from any one of acetone, butanone or nitrogen methyl pyrrolidone, or a combination of at least two thereof.

[0015] Preferably, the initiator is selected from azobisisobutyronitrile (AIBN) or dibenzoyl peroxide (BPO).

[0016] Preferably, the amine neutralizing agent is selected from triethylamine and / or AMP-95.

[0017] Preferably, the molar ratio of diisocyanate to macromolecular chain extender in the preparation raw materials is 1:0.85-0.92, for example, 1:0.85, 1:0.86, 1:0.88, 1:0.90 or 1:0.92.

[0018] Preferably, the molar ratio of diisocyanate to bis(hydroxymethyl)propionic acid in the preparation raw materials is 1:0.02-0.04, for example, 1:0.02, 1:0.03 or 1:0.04.

[0019] Preferably, the small molecule chain extender may further include any one of other small molecule diols or small molecule diamines, or a combination of at least two of them.

[0020] Preferably, the other small molecule diols are selected from ethylene glycol and / or 1,4-butanediol;

[0021] Preferably, the small molecule diamine includes ethylenediamine.

[0022] Preferably, the molar ratio of other small molecule diols to diisocyanate in the preparation raw materials is 0.05-0.13:1, for example, 0.05:1, 0.06:1, 0.08:1, 0.10:1, 0.12:1 or 0.13:1.

[0023] Preferably, the molar ratio of diisocyanate to unsaturated blocking agent in the preparation raw materials is 1:0.03-0.08, for example, 1:0.03, 1:0.04, 1:0.05, 1:0.06, 1:0.07 or 1:0.08.

[0024] Preferably, the amount of the organic solvent in the preparation raw materials is 10-30% of the total mass of the diisocyanate, for example, 10%, 15%, 18%, 20%, 23%, 25%, 28% or 30%.

[0025] Preferably, the amount of water in the preparation raw material is 180-300% of the total mass of the diisocyanate, for example, 180%, 200%, 220%, 230%, 250%, 280% or 300%.

[0026] Preferably, the amount of the initiator in the raw materials is 0.3-0.8% of the total mass of the diisocyanate and the unsaturated blocking agent, for example, 0.3%, 0.4%, 0.5%, 0.6%, 0.7% or 0.8%.

[0027] Preferably, the amount of the raw material amine neutralizer used is 0.1-0.3% of the total mass of the raw materials, such as 0.1%, 0.13%, 0.15%, 0.18%, 0.2%, 0.25%, 0.28% or 0.3%.

[0028] On the other hand, the present invention provides a method for preparing the bio-based lithium battery negative electrode binder as described above, the preparation method comprising the following steps:

[0029] (1) reacting a diisocyanate with an unsaturated blocking agent to obtain a diisocyanate with a partial unsaturated bond;

[0030] (2) reacting a diisocyanate with a partially unsaturated bond and a macromolecular chain extender under the initiation of an initiator;

[0031] (3) adding an organic solvent to the reaction system obtained in step (2), and then adding a small molecule chain extender, and reacting until the viscosity no longer increases;

[0032] (4) adding the reaction solution obtained in step (3) to water, adjusting the pH with an amine neutralizer, and removing the organic solvent;

[0033] (5) Using water to adjust the solid content of the system to obtain the bio-based lithium battery negative electrode adhesive.

[0034] Preferably, the reaction temperature in step (1) is 30-70°C, for example 30°C, 40°C, 50°C, 55°C, 60°C, 65°C or 70°C, preferably 50-70°C, and the reaction time is 1-6h, for example 1h, 2h, 3h, 4h, 4.5h, 5h, 5.5h or 6h, preferably 4-6h.

[0035] Preferably, the reaction temperature in step (2) is 80-90°C, such as 80°C, 83°C, 85°C, 88°C or 90°C, and the reaction time is 6-10h, such as 6h, 7h, 8h, 9h or 10h.

[0036] In the present invention, the reaction in step (2) needs to be isolated from water vapor.

[0037] Preferably, the reaction temperature in step (3) is 80-90°C, such as 80°C, 85°C, 88°C or 90°C.

[0038] Preferably, the amount of water used in step (4) accounts for 50-60% of the total mass of the reaction solution and water, such as 50%, 53%, 55%, 58% or 60%.

[0039] Preferably, in step (4), the pH is adjusted to 7-9, for example, 7, 7.2, 7.4, 7.6, 7.8, 8, 8.3, 8.5, 8.8 or 9, using an amine neutralizer.

[0040] Preferably, the removal of the organic solvent in step (4) can be achieved by rotary evaporation.

[0041] Preferably, the solid content in step (5) is 35-40%, such as 35%, 36%, 37%, 38%, 39% or 40%.

[0042] In another aspect, the present invention provides a lithium battery negative electrode, comprising the bio-based lithium battery negative electrode binder as described above.

[0043] In another aspect, the present invention provides a bio-based lithium battery, comprising the lithium battery negative electrode as described above.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] The bio-based lithium battery negative electrode adhesive material of the present invention has strong solvent and corrosion resistance, can be immersed in a strong electrolyte for a long time without dissolving, and has a controllable swelling rate. It can be used in lithium batteries to meet high-fast charging applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 This is the infrared spectrum of the product obtained in step (1) of Example 1.

[0047] Figure 2 This is the infrared spectrum of the product obtained in step (5) of Example 1. DETAILED DESCRIPTION

[0048] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0049] Example 1

[0050] This embodiment provides a bio-based lithium battery negative electrode adhesive, the preparation method of which includes the following steps:

[0051] (1) Pentamethylene diisocyanate and unsaturated end-capping agent hydroxyethyl methacrylate were reacted at a molar ratio of 1:0.05 at 50° C. for 3 h to obtain a diisocyanate with a partially unsaturated bond;

[0052] (2) reacting the partially unsaturated diisocyanate obtained in step (1) with a macromolecular chain extender polytrimethylene ether glycol (number average molecular weight 2000, SK, Korea) at a molar ratio of 1:0.85 at 80° C., initiating with initiator AIBN (the amount of initiator used is 0.3% of the total mass of the diisocyanate and the unsaturated end-capping agent), and reacting for 8 h. Water vapor must be isolated during the reaction;

[0053] (3) adding an organic solvent, acetone, to the reaction system obtained in step (2) (the amount of acetone added is 20% of the mass of pentamethylene diisocyanate), and then adding a small molecule chain extender, bis(hydroxymethyl)propionic acid (the molar ratio of bis(hydroxymethyl)propionic acid to pentamethylene diisocyanate is 0.03:1), and reacting at 80° C. until the viscosity no longer increases;

[0054] (4) adding the reaction solution obtained in step (3) to water, wherein the amount of water accounts for 50% of the total mass of the reaction solution and water, and adjusting the pH to 8 using an amine neutralizer triethylamine, and removing the organic solvent by rotary evaporation;

[0055] (5) adding water to adjust the solid content of the system to 40% to obtain the bio-based lithium battery negative electrode adhesive.

[0056] The infrared spectrum of the product obtained in step (1) of this embodiment is as follows: Figure 1 As shown, at 2100-2400cm -1 is the characteristic absorption peak of "-NCO", Figure 2 The infrared spectrum of the product obtained in step (5) is shown in FIG.-1 The characteristic absorption peak of “-NCO” almost disappears.

[0057] Example 2

[0058] This embodiment provides a bio-based lithium battery negative electrode adhesive, the preparation method of which includes the following steps:

[0059] (1) reacting pentamethylene diisocyanate and unsaturated end-capping agent hydroxyethyl methacrylate at a molar ratio of 1:0.08 at 70° C. for 4 h to obtain a diisocyanate with a partially unsaturated bond;

[0060] (2) reacting the partially unsaturated diisocyanate obtained in step (1) with a macromolecular chain extender, polycaprolactone (number average molecular weight 2000, Daicel, Japan), at a molar ratio of 1:0.85 at 85° C., with initiator BPO (the amount of initiator used is 0.3% of the total mass of the diisocyanate and the unsaturated end-capping agent), for 8 h, and isolating from moisture during the reaction;

[0061] (3) adding an organic solvent, butanone, to the reaction system obtained in step (2) (the amount of butanone added is 10% of the mass of pentamethylene diisocyanate), and then adding a small molecule chain extender, bis(hydroxymethyl)propionic acid (the molar ratio of bis(hydroxymethyl)propionic acid to pentamethylene diisocyanate is 0.04:1), and reacting at 85° C. until the viscosity no longer increases;

[0062] (4) adding the reaction solution obtained in step (3) to water, wherein the amount of water accounts for 50% of the total mass of the reaction solution and water, and adjusting the pH to 8.5 using an amine neutralizer triethylamine, and removing the organic solvent by rotary evaporation;

[0063] (5) adding water to adjust the solid content of the system to 40% to obtain the bio-based lithium battery negative electrode adhesive.

[0064] Example 3

[0065] This embodiment provides a bio-based lithium battery negative electrode adhesive, the preparation method of which includes the following steps:

[0066] (1) Pentamethylene diisocyanate and unsaturated end-capping agent hydroxyethyl methacrylate were reacted at a molar ratio of 1:0.04 at 60° C. for 5 h to obtain a diisocyanate with a partially unsaturated bond;

[0067] (2) reacting the partially unsaturated diisocyanate obtained in step (1) with a macromolecular chain extender, castor oil-modified polyol (number average molecular weight 2000, Vantellus, USA) at a molar ratio of 1:0.9 at 90° C., with initiator BPO (the amount of initiator used is 0.5% of the total mass of the diisocyanate and the unsaturated end-capping agent), for 8 h, and isolating from moisture during the reaction;

[0068] (3) adding an organic solvent, butanone, to the reaction system obtained in step (2) (the amount of butanone added is 30% of the mass of pentamethylene diisocyanate), and then adding a small molecule chain extender, bis(hydroxymethyl)propionic acid (the molar ratio of bis(hydroxymethyl)propionic acid to pentamethylene diisocyanate is 0.02:1), and reacting at 80° C. until the viscosity no longer increases;

[0069] (4) adding the reaction solution obtained in step (3) to water, wherein the amount of water accounts for 50% of the total mass of the reaction solution and water, and adjusting the pH to 7.4 using an amine neutralizer triethylamine, and removing the organic solvent by rotary evaporation;

[0070] (5) adding water to adjust the solid content of the system to 40% to obtain the bio-based lithium battery negative electrode adhesive.

[0071] Example 4

[0072] This embodiment provides a bio-based lithium battery negative electrode adhesive, the preparation method of which includes the following steps:

[0073] (1) reacting pentamethylene diisocyanate and unsaturated end-capping agent hydroxyethyl methacrylate at a molar ratio of 1:0.03 at 40° C. for 6 h to obtain a diisocyanate with a partially unsaturated bond;

[0074] (2) reacting the partially unsaturated diisocyanate obtained in step (1) with a macromolecular chain extender, polytetramethylene ether glycol (number average molecular weight 2000, Hyosung, Korea), at a molar ratio of 1:0.92 at 90° C., with initiator AIBN (the amount of initiator used was 0.7% of the total mass of the diisocyanate and the unsaturated end-capping agent), for 10 h, and isolating from moisture during the reaction;

[0075] (3) adding an organic solvent, butanone, to the reaction system obtained in step (2) (the amount of butanone added is 15% of the mass of pentamethylene diisocyanate), and then adding a small molecule chain extender, bis(hydroxymethyl)propionic acid (the molar ratio of bis(hydroxymethyl)propionic acid to pentamethylene diisocyanate is 0.03:1), and reacting at 90° C. until the viscosity no longer increases;

[0076] (4) adding the reaction solution obtained in step (3) to water, wherein the amount of water accounts for 50% of the total mass of the reaction solution and water, and adjusting the pH to a weak alkaline state using an amine neutralizer AMP-95, and removing the organic solvent by rotary evaporation;

[0077] (5) adding water to adjust the solid content of the system to 40% to obtain the bio-based lithium battery negative electrode adhesive.

[0078] Example 5

[0079] This embodiment provides a bio-based lithium battery negative electrode adhesive, the preparation method of which includes the following steps:

[0080] (1) reacting pentamethylene diisocyanate and unsaturated end-capping agent hydroxyethyl methacrylate at a molar ratio of 1:0.03 at 30° C. for 6 h to obtain a diisocyanate with a partially unsaturated bond;

[0081] (2) reacting the partially unsaturated diisocyanate obtained in step (1) with a macromolecular chain extender polytrimethylene ether glycol (weight-average molecular weight of 2000) at a molar ratio of 1:0.85 at 80° C., using initiator AIBN (the amount of initiator used is 0.8% of the total mass of the diisocyanate and the unsaturated end-capping agent) for 9 h, and isolating from moisture during the reaction;

[0082] (3) adding an organic solvent, acetone (the amount of butanone added is 25% of the mass of pentamethylene diisocyanate), to the reaction system obtained in step (2), and then adding a small molecule chain extender, bis(hydroxymethyl)propionic acid (the molar ratio of bis(hydroxymethyl)propionic acid to pentamethylene diisocyanate is 0.03:1) and ethylene glycol (the molar ratio of ethylene glycol to pentamethylene diisocyanate is 0.05:1), and reacting at 85° C. until the viscosity no longer increases;

[0083] (4) adding the reaction solution obtained in step (3) to water, wherein the amount of water accounts for 50% of the total mass of the reaction solution and water, and adjusting the pH to 8 using an amine neutralizer triethylamine, and removing the organic solvent by rotary evaporation;

[0084] (5) adding water to adjust the solid content of the system to 40% to obtain the bio-based lithium battery negative electrode adhesive.

[0085] Example 6

[0086] This embodiment provides a bio-based lithium battery negative electrode adhesive, the preparation method of which includes the following steps:

[0087] (1) Lysine diisocyanate and unsaturated end-capping agent hydroxyethyl methacrylate were reacted at a molar ratio of 1:0.03 at 60° C. for 3 h to obtain a diisocyanate with a partially unsaturated bond;

[0088] (2) reacting the partially unsaturated diisocyanate obtained in step (1) with a macromolecular chain extender polytrimethylene ether glycol (number average molecular weight 2000, SK, Korea) at a molar ratio of 1:0.88 at 90° C., using initiator AIBN (the amount of initiator used is 0.5% of the total mass of the diisocyanate and the unsaturated end-capping agent) for 8 h, and isolating from moisture during the reaction;

[0089] (3) adding an organic solvent, nitrogen methyl pyrrolidone (the amount of nitrogen methyl pyrrolidone added is 20% of the mass of lysine diisocyanate), to the reaction system obtained in step (2), and then adding a small molecule chain extender, bis(hydroxymethyl)propionic acid (the molar ratio of bis(hydroxymethyl)propionic acid to lysine diisocyanate is 0.02:1) and 1,4-butanediol (the molar ratio of 1,4-butanediol to lysine diisocyanate is 0.05:1), and reacting at 80° C. until the viscosity no longer increases;

[0090] (4) adding the reaction solution obtained in step (3) to water, wherein the amount of water accounts for 50% of the total mass of the reaction solution and water, and adjusting the pH to 7 using an amine neutralizer triethylamine, and removing the organic solvent by rotary evaporation;

[0091] (5) adding water to adjust the solid content of the system to 40% to obtain the bio-based lithium battery negative electrode adhesive.

[0092] Example 7

[0093] This embodiment provides a bio-based lithium battery negative electrode adhesive, the preparation method of which includes the following steps:

[0094] (1) reacting 2,5-furan diisocyanate and unsaturated end-capping agent hydroxyethyl acrylate at a molar ratio of 1:0.05 at 60° C. for 5 h to obtain a diisocyanate with a partially unsaturated bond;

[0095] (2) reacting the partially unsaturated diisocyanate obtained in step (1) with a macromolecular chain extender, polycaprolactone (number average molecular weight 2000, Daicel, Japan), at a molar ratio of 1:0.92 at 90° C., with initiator BPO (the amount of initiator used is 0.8% of the total mass of the diisocyanate and the unsaturated end-capping agent), for 7 h, and isolating from moisture during the reaction;

[0096] (3) adding an organic solvent, nitrogen methyl pyrrolidone (the amount of nitrogen methyl pyrrolidone added is 10% of the mass of 2,5-furan diisocyanate), to the reaction system obtained in step (2), and then adding a small molecule chain extender, bishydroxymethyl propionic acid (the molar ratio of bishydroxymethyl propionic acid to 2,5-furan diisocyanate is 0.04:1) and ethylene glycol (the molar ratio of ethylene glycol to 2,5-furan diisocyanate is 0.13:1), and reacting at 90° C. until the viscosity no longer increases;

[0097] (4) adding the reaction solution obtained in step (3) to water, wherein the amount of water accounts for 50% of the total mass of the reaction solution and water, and adjusting the pH to 9 using an amine neutralizer triethylamine, and removing the organic solvent by rotary evaporation;

[0098] (5) adding water to adjust the solid content of the system to 40% to obtain the bio-based lithium battery negative electrode adhesive.

[0099] Example 8

[0100] This embodiment provides a bio-based lithium battery negative electrode adhesive, the preparation method of which includes the following steps:

[0101] (1) reacting pentamethylene diisocyanate and unsaturated end-capping agent hydroxypropyl acrylate at a molar ratio of 1:0.03 at 70° C. for 4 h to obtain a diisocyanate with a partially unsaturated bond;

[0102] (2) The diisocyanate with partially unsaturated bonds obtained in step (1) and the macromolecular chain extender polycaprolactone (number average molecular weight of 2000, Daicel, Japan) were reacted at a molar ratio of 1:0.85 at 85°C, and the initiator AIBN was used for initiation (the amount of initiator was 0.3% of the total mass of the diisocyanate and the unsaturated end-capping agent). The reaction was carried out for 7 hours, and water vapor was isolated during the reaction;

[0103] (3) adding an organic solvent, nitrogen methyl pyrrolidone (the amount of nitrogen methyl pyrrolidone added is 30% of the mass of pentamethylene diisocyanate), to the reaction system obtained in step (2), and then adding a small molecule chain extender, bis(hydroxymethyl)propionic acid (the molar ratio of bis(hydroxymethyl)propionic acid to pentamethylene diisocyanate is 0.02:1) and ethylenediamine (the molar ratio of ethylenediamine to pentamethylene diisocyanate is 0.08:1), and reacting at 85° C. until the viscosity no longer increases;

[0104] (4) adding the reaction solution obtained in step (3) to water, wherein the amount of water accounts for 50% of the total mass of the reaction solution and water, and adjusting the pH to 9 using an amine neutralizer triethylamine, and removing the organic solvent by rotary evaporation;

[0105] (5) adding water to adjust the solid content of the system to 40% to obtain the bio-based lithium battery negative electrode adhesive.

[0106] Example 9

[0107] The only difference from Example 1 is that the weight average molecular weight of the macromolecular chain extender polytrimethylene ether glycol is 1000 (purchased from SK, South Korea).

[0108] Example 10

[0109] The only difference from Example 1 is that the number average molecular weight of the macromolecular chain extender polytetramethylene ether glycol is 3000 (purchased from Hyosung, Korea).

[0110] Comparative Example 1

[0111] The only difference from Example 1 is that no initiator is added in step (2).

[0112] Comparative Example 2

[0113] The only difference from Example 1 is that the macromolecular chain extender in step (2) is replaced by an equimolar amount of polycarbonate diol with a molecular weight of 2000 purchased from Ube Corporation of Japan.

[0114] Comparative Example 3

[0115] The only difference from Example 4 is that the macromolecular chain extender in step (2) is replaced by an equimolar amount of polytetramethylene ether glycol (number average molecular weight of 3500, Hyosung, Korea).

[0116] Comparative Example 4

[0117] The only difference from Example 1 is that in step (2), the macromolecular chain extender is replaced by an equimolar amount of polytrimethylene ether glycol (number average molecular weight of 600, SK, Korea).

[0118] The adhesive materials prepared in the examples and comparative examples were dried to prepare square films with a length, width and thickness of 10 mm × 10 mm × 50 μm, which were then immersed in the electrolyte of a 3C battery for 4 h in the dark. The films were then taken out and their dissolution and deformation rates were tested.

[0119] Dissolution condition: record the initial mass m1 of the square membrane, soak it in electrolyte (EC (ethylene carbonate): EMC (ethyl methyl carbonate): DMC (dimethyl carbonate) = 3:5:2) for 4 hours, take it out, place it in a 70°C oven and dry it to constant weight, and weigh the mass m2. Test the weight loss rate [1-(m1-m2) / m1]×100%.

[0120] Deformation rate: length × width after test / (initial length × width) × 100%.

[0121] The test results are shown in Table 1.

[0122] Table 1

[0123] Dissolution Deformation rate Example 1 93.7％ 36％ Example 2 91.6％ 35％ Example 3 95.2％ 29％ Example 4 89.3％ 31％ Example 5 92.6％ 33％ Example 6 91.7％ 36％ Example 7 88.2％ 33％ Example 8 89.5％ 31％ Example 9 81.9％ 48％ Example 10 88.7％ 39％ Comparative Example 1 Completely dissolved NA Comparative Example 2 Completely dissolved NA Comparative Example 3 79.7％ 52％ Comparative Example 4 78.6％ 66％

[0124] The polyurethanes in the comparative examples all dissolved in the system. The deformation rate of this product was within 48%.

[0125] This is achieved because the adhesive material of the present invention contains a large number of conventional alkane segments, which have strong solvent and corrosion resistance. Secondly, unsaturated bonds are introduced into the main chain segment, and after the double bonds are cross-linked with additives such as AIBN, its solvent resistance is further improved, so that it will not dissolve even after long-term immersion in a strong electrolyte, and the swelling rate can also be controlled.

[0126] The applicant states that the present invention uses the above-described embodiments to illustrate the bio-based lithium battery negative electrode binder, its preparation method, and its application. However, the present invention is not limited to the above-described embodiments, and this does not necessarily mean that the present invention must rely on the above-described embodiments for implementation. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for various raw materials in the present invention, addition of auxiliary ingredients, and selection of specific methods, etc., fall within the scope of protection and disclosure of the present invention.

Claims

1. A bio-based lithium battery negative electrode adhesive, characterized in that: The raw materials for preparing the bio-based lithium battery negative electrode adhesive include diisocyanate, a macromolecular chain extender, a small molecule chain extender, an unsaturated end-capping agent, an organic solvent, water, an initiator, and an amine neutralizer, wherein the macromolecular chain extender is at least one of bio-based polyester polyol or polyether polyol, and the small molecule chain extender includes bis(hydroxymethyl)propionic acid.

2. The bio-based lithium battery negative electrode adhesive according to claim 1, characterized in that The diisocyanate is a bio-based diisocyanate.

3. The bio-based lithium battery negative electrode adhesive according to claim 1, characterized in that The bio-based diisocyanate is selected from any one or a combination of at least two of pentamethylene diisocyanate, lysine diisocyanate or 2,5-furan diisocyanate; Preferably, the macromolecular chain extender is selected from any one of polytrimethylene ether glycol, polycaprolactone, castor oil modified polyol or polytetramethylene ether glycol, or a combination of at least two thereof.

4. The bio-based lithium battery negative electrode adhesive according to claim 1, characterized in that The number average molecular weight of the macromolecular chain extender is 1000-3000.

5. The bio-based lithium battery negative electrode adhesive according to claim 4, characterized in that: The number average molecular weight of the macromolecular chain extender is 2000.

6. The bio-based lithium battery negative electrode adhesive according to claim 1, characterized in that The unsaturated end-capping agent is selected from any one of hydroxyethyl methacrylate, hydroxyethyl acrylate or hydroxypropyl acrylate, or a combination of at least two thereof; Preferably, the organic solvent is selected from any one or a combination of at least two of acetone, butanone or nitrogen methyl pyrrolidone; Preferably, the initiator is selected from azobisisobutyronitrile or dibenzoyl peroxide; Preferably, the amine neutralizing agent is selected from triethylamine and / or AMP-95; Preferably, the molar ratio of diisocyanate to macromolecular chain extender in the preparation raw materials is 1:0.85-0.92 Preferably, the molar ratio of diisocyanate to bis(hydroxymethyl)propionic acid in the preparation raw materials is 1:0.02-0.04; Preferably, the small molecule chain extender may further include any one or a combination of at least two of other small molecule diols or diamines; Preferably, the other small molecule diols are selected from ethylene glycol and / or 1,4-butanediol, and the small molecule diamines include ethylenediamine; Preferably, the molar ratio of other small molecule diols or diamines to diisocyanate in the preparation raw materials is 0.05-0.13:1; Preferably, the molar ratio of diisocyanate to unsaturated blocking agent in the preparation raw materials is 1:0.03-0.08; Preferably, the amount of organic solvent in the preparation raw materials is 10-30% of the mass of diisocyanate; Preferably, the amount of water used in the raw material preparation is such that the solid content of the bio-based lithium battery negative electrode binder is 35-40%; Preferably, the amount of the initiator in the raw material is 0.3-0.8% of the total mass of the diisocyanate and the unsaturated blocking agent; Preferably, the amount of the amine neutralizer used in the preparation of raw materials is 0.1-0.3% of the total mass of the raw materials.

7. The method for preparing a bio-based lithium battery negative electrode adhesive according to any one of claims 1 to 6, characterized in that: The preparation method comprises the following steps: (1) reacting a diisocyanate with an unsaturated blocking agent to obtain a diisocyanate with a partial unsaturated bond; (2) reacting a diisocyanate with a partially unsaturated bond and a macromolecular chain extender under the initiation of an initiator; (3) adding an organic solvent to the reaction system obtained in step (2), and then adding a small molecule chain extender, and reacting until the viscosity no longer increases; (4) adding the reaction solution obtained in step (3) to water, adjusting the pH with an amine neutralizer, and removing the organic solvent; (5) Using water to adjust the solid content of the system to obtain the bio-based lithium battery negative electrode adhesive.

8. The preparation method according to claim 7, characterized in that The reaction temperature in step (1) is 30-70° C., and the reaction time is 1-6 h; Preferably, the reaction temperature in step (2) is 80-90° C., and the reaction time is 6-10 h; Preferably, the reaction temperature in step (3) is 80-90°C; Preferably, the amount of water used in step (4) accounts for 50-60% of the total mass of the reaction solution and water; Preferably, in step (4), the pH is adjusted to 7-9 using an amine neutralizer; Preferably, the removal of the organic solvent in step (4) is achieved by rotary evaporation; Preferably, the solid content in step (5) is 30-40%.

9. A lithium battery negative electrode, characterized in that: The lithium battery negative electrode comprises the bio-based lithium battery negative electrode binder according to any one of claims 1 to 6.

10. A bio-based lithium battery, characterized in that: The bio-based lithium battery comprises the lithium battery negative electrode according to any one of claims 1 to 6.

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