Polysiloxane modified aspartate resin and solid electrolyte

Abstract

The invention provides polysiloxane modified aspartic ester resin and a solid electrolyte, and relates to the technical field of polymer synthesis. The polysiloxane modified aspartic ester resin contains a plurality of aspartic ester structures and alkoxy groups, and has relatively high reaction activity and polarity. The solid electrolyte prepared from the polysiloxane modified aspartic ester resin has relatively low interface impedance and a relatively high electrochemical window.

Description

Technical Field

[0001] This invention belongs to the field of polymer synthesis technology and relates to a polysiloxane-modified aspartic acid ester resin and a solid electrolyte. Background Technology

[0002] Replacing liquid electrolytes with solid polymer electrolytes is currently an effective measure to solve battery safety issues. Existing technologies have reported various solid polymer electrolyte materials, among which polyethylene glycol (PEG) has advantages such as high voltage stability and improved lithium anode compatibility. However, it also has drawbacks such as low room temperature conductivity and easy crystallization at room temperature leading to poor conductivity. Aspartic polyurea possesses excellent mechanical properties and chemical corrosion resistance, which can improve the cycle stability of battery operation, making it a promising solid polymer electrolyte matrix. Existing technologies such as CN116505066A and CN118852582A disclose solid electrolytes based on aspartic polyurea, all of which introduce polyethylene glycol or polyether segments into the aspartic polyurea. For example, in CN116505066A, the polyethylene glycol segment is located on the side chain, while in CN118852582A, the polyether segment is located on the main chain to improve its ionic conductivity. However, it still suffers from drawbacks such as high impedance, a low electrochemical window, and the high crystallinity of PEG.

[0003] Therefore, existing solid electrolytes based on aspartic acid ester resins require further improvement. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a polysiloxane-modified aspartic acid ester resin and a solid electrolyte.

[0005] The technical solution of the present invention is as follows:

[0006] A polysiloxane-modified aspartic acid ester resin has the structure shown in formula (1).

[0007]

[0008] Among them, R1, R2, R3, R5, R6, R 11 R 12 R 13 R 14 R 15 and R 16 Individually selected from C1-C4 alkyl groups, R7, R8 and R 10 R4 is selected from C1-C4 alkyl or C1-C4 alkoxy, R9 is selected from C1-C4 alkyl, C1-C4 alkoxy or the structure shown in formula (2) below, a≥0, b≥0, a+b≤10, b / (a+b)≤0.5.

[0009]

[0010] Among them, R 17 Selected from C1-C6 divalent alkyl groups, R 18 and R 19 The individual is selected from C1-C4 alkyl groups.

[0011] Preferably, the values ​​of a and b satisfy: b / (a+b)≤0.3.

[0012] Preferably, the values ​​of a and b satisfy: b = 0, 0 ≤ a ≤ 7.

[0013] Preferably, R1, R2, R3, R5 and R6 are individually selected from methyl or ethyl.

[0014] Preferably, the polysiloxane-modified aspartic acid ester resin is obtained by Michael addition reaction of the poly-primary amine polysiloxane corresponding to the structure shown in formula (1) with dialkyl maleate or dialkyl fumarate.

[0015] A solid electrolyte comprising the following raw material components: siloxane-modified polyaspartic acid ester resin, lithium salt, and isocyanate curing agent as described in any of the above embodiments.

[0016] Preferably, the weight of the lithium salt is 5-50% of the weight of the siloxane-modified polyaspartic acid ester resin.

[0017] Preferably, the lithium salt is selected from one or a combination of two or more of lithium hexafluorophosphate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium tetrafluoroborate, lithium perchlorate, lithium difluorophosphate, lithium difluorobis(oxalate)phosphate, lithium bis(difluorosulfonyl)imide, lithium bis(oxalate)borate, lithium difluorooxalateborate, lithium nitrate, lithium trifluoromethanesulfonate, and tris(trifluoromethanesulfonyl)methyllithium.

[0018] Preferably, the molar ratio of NH groups in the siloxane-modified polyaspartic acid ester resin to NCO groups in the isocyanate curing agent is 0.8-1.2:1.

[0019] Preferably, the isocyanate curing agent is selected from one or a combination of two or more of HDI trimer, HDI biuret, HDI diuret, HDI urethane, HDI urethane, IPDI trimer, IPDI urethane, IPDI urethane, CHDI urethane, CHDI urethane, HMDI, IPDI and CHDI.

[0020] The beneficial effects of this invention are:

[0021] (1) The siloxane-modified polyaspartic acid ester polymer of the present invention contains multiple aspartic acid ester structures and multiple alkoxy groups bonded to Si, which have high reactivity and polarity. The NH groups on the aspartic acid ester structure can continue to react with NCO groups, etc., and the alkoxy groups on Si can undergo partial or complete hydrolysis and condensation to form a cross-linked structure.

[0022] (2) The present invention uses a siloxane-modified polyaspartic acid ester polymer with a specific structure. The excellent flexibility and high and low temperature resistance of polysiloxane make the solid electrolyte have good ionic conductivity at low temperature. The siloxane-modified polyaspartic acid ester polymer contains multiple carbonyl and alkoxy structures, which have high polarity and higher ionic conductivity than conventional polysiloxane. Moreover, it has low interfacial impedance and high electrochemical window. Detailed Implementation

[0023] The technical solution of the present invention will be further explained and described below through specific embodiments.

[0024] On the one hand, the present invention proposes a polysiloxane-modified aspartic acid ester resin having the structure shown in formula (1).

[0025]

[0026] Among them, R1, R2, R3, R5, R6, R 11 R 12 R 13 R 14 R 15 and R 16 Individually selected from C1-C4 alkyl groups, R7, R8 and R 10 R4 is selected from C1-C4 alkyl or C1-C4 alkoxy, R9 is selected from C1-C4 alkyl, C1-C4 alkoxy or the structure shown in formula (2) below, a≥0, b≥0, a+b≤10, b / (a+b)≤0.5.

[0027]

[0028] Among them, R 17 Selected from C1-C6 divalent alkyl groups, R 18 and R 19 The individual is selected from C1-C4 alkyl groups.

[0029] The polysiloxane-modified aspartic acid ester resin of the present invention has the following structural features: (1) It contains multiple aspartic acid ester structures and alkoxy groups on Si, which have both high reactivity and high polarity. The NH groups on the aspartic acid ester structure can react with active groups such as isocyanate groups to obtain a cross-linked structure. When the alkoxy groups come into contact with moisture or water vapor, they can undergo hydrolysis and condensation to form a cross-linked structure; (2) The polysiloxane is the main chain, which has good high and low temperature resistance, flexibility, etc. The multiple aspartic acid ester structures are located on the side chains of the polysiloxane main chain, which have a high degree of freedom. Therefore, the polysiloxane-modified aspartic acid ester resin of the present invention can synergistically exert the performance of polysiloxane and aspartic acid ester.

[0030] In some embodiments, the values ​​of a and b satisfy: b / (a+b)≤0.3. For example, the value of a can be any value or any value between 0, 1, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, etc., without any particular restriction; b / (a+b) represents the molar percentage of -SiR4R9O- linkages in the above-mentioned polysiloxane-modified aspartic acid ester resin. When R9 is not the structure shown in the above formula (2), for example, R9 is a C1-C4 alkyl group, if the value of b / (a+b) is too high, it will affect the reactivity and polarity of the polysiloxane-modified aspartic acid ester resin, which is not conducive to the performance of the solid electrolyte and has high interfacial impedance. For example, the value of b / (a+b) can be any value or any value between 0, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, etc., without any particular restriction.

[0031] In some embodiments, the values ​​of a and b satisfy: b = 0, 0 ≤ a ≤ 7. For example, the value of a can be any value or any value in between from 0, 1, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, etc., without any particular restriction.

[0032] In some embodiments, R1, R2, R3, R5, and R6 are individually selected from methyl or ethyl.

[0033] In some embodiments, the polysiloxane-modified aspartic acid ester resin is obtained by Michael addition reaction of the poly-primary amine polysiloxane corresponding to the structure shown in formula (1) with dialkyl maleate or dialkyl fumarate.

[0034] Taking the structure shown in equation (1) above, where b = 0, as an example, the polyamine polysiloxane has the structure shown in equation (3) below.

[0035]

[0036] Among them, R1, R2, R3, R5, R6, R7, R8 and R 10The meaning is as above.

[0037] For the polyamine polysiloxane shown in formula (3) above, there are no particular restrictions on the source. It can be obtained directly from the market, such as Jiangxi Hongbai New Material Co., Ltd., or it can be prepared according to existing technology. For example, one preparation method is: 3-aminopropyltrimethoxysilane is added to methoxyisopropanol, then a catalyst and water are added, and the mixture is stirred at 50℃-60℃ for 10h-15h for hydrolysis, and then vacuum dehydration is performed to obtain the polyamine polysiloxane. Among them, the catalyst can be acetic acid, organotin, etc., and the weight percentage of 3-aminopropyltrimethoxysilane, methoxyisopropanol, catalyst and water can be (40-50)%:(40-50)%:(0-5)%:(5-16)%. By adjusting the weight percentage of water, different average degrees of polymerization a can be obtained. For example, when a=1, the above polyamine polysiloxane can be an aminopropyltrimethoxysilane trimer; when a=5, the above polyamine polysiloxane can be an aminopropyltrimethoxysilane heptamer. In the above-mentioned method for preparing polyamine polysiloxane, when aminopropylmethyldimethoxy is added to the raw material, a -SiR4R9O- structure can be introduced into the polyamine polysiloxane, wherein R4 is methyl and R9 is -(CH2)3NH2; when dimethyldimethoxysilane is added to the raw material, a -SiR4R9O- structure is introduced into the polyamine polysiloxane, wherein both R4 and R9 are methyl.

[0038] For dialkyl maleate or dialkyl fumarate, it can be dimethyl maleate, diethyl maleate, dimethyl fumarate, diethyl fumarate, dibutyl maleate, etc., without any particular restrictions. For Michael addition reaction, this is well known to those skilled in the art. Taking b=0 and diethyl maleate in polysiloxane modified aspartic acid ester resin as an example, according to the above formula (3), the polysiloxane and diethyl maleate are added into the reaction vessel in a molar ratio of 1:(1-1.1)(a+2), heated to 70-100℃ and reacted for 72-144h. Then, it is purified by short-path evaporator to obtain polysiloxane modified aspartic acid ester resin.

[0039] On the other hand, the present invention also proposes a solid electrolyte, the raw material components of which include: siloxane-modified polyaspartic acid ester resin, lithium salt and isocyanate curing agent as described in any of the above embodiments.

[0040] In some embodiments, the weight of the lithium salt is 5-50% of the weight of the siloxane-modified polyaspartic acid ester resin. For example, the weight of the lithium salt can be any value or any value between 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, and 50% of the weight of the siloxane-modified polyaspartic acid ester resin, without particular limitation. Further, to improve ionic conductivity, the weight of the lithium salt is 15-40% of the weight of the siloxane-modified polyaspartic acid ester resin.

[0041] In some embodiments, the lithium salt is selected from one or a combination of two or more of lithium hexafluorophosphate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium tetrafluoroborate, lithium perchlorate, lithium difluorophosphate, lithium difluorobis(oxalato)phosphate, lithium bis(difluorosulfonyl)imide, lithium bis(oxalato)borate, lithium difluorooxalatoborate, lithium nitrate, lithium trifluoromethanesulfonate, and tris(trifluoromethanesulfonyl)methyllithium.

[0042] In this invention, lithium salt can be added directly in solid form or pre-formed into a liquid form, i.e., liquid lithium salt. For liquid lithium salt, solid lithium salt can be mixed with a solvent and additives. The solvent can be propylene carbonate (PC), ethylene carbonate (EC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), etc.; the additive can be fluoroethylene carbonate (FEC), and the volume ratio of the additive to the solvent can be 3-10%. The concentration of solid lithium salt in the liquid lithium salt can be 0.5-3 mol / L. Using liquid lithium salt can reduce the viscosity of the solid electrolyte precursor (uncured solid electrolyte), which is beneficial for the solid electrolyte precursor to permeate the membrane and form a solid electrolyte.

[0043] In some embodiments, the molar ratio of NH groups in the siloxane-modified polyaspartic acid ester resin to NCO groups in the isocyanate curing agent is 0.8-1.2:1. For example, the molar ratio of NH groups to NCO groups can be 0.8:1, 0.82:1, 0.85:1, 0.87:1, 0.9:1, 0.92:1, 0.95:1, 0.97:1, 1:1, 1.02:1, 1.03:1, 1.05:1, 1.08:1, 1.1:1, 1.12:1, 1.15:1, 1.18:1, or 1.2:1, without particular limitation.

[0044] In some embodiments, the isocyanate curing agent is selected from one or a combination of two or more of HDI trimer, HDI biuret, HDI diuret, HDI urethane, HDI urethane, IPDI trimer, IPDI urethane, IPDI urethane, CHDI urethane, CHDI urethane, HMDI, IPDI and CHDI.

[0045] For urethane-type isocyanate curing agents, such as the HDI urethane, IPDI urethane, and CHDI urethane mentioned above, they can be adducts of the corresponding isocyanate monomers with polyether polyols (such as polypropylene glycol PPG, polytetrahydrofuran ether polyol PTMEG), polyester polyols (such as polycaprolactone polyol, polycarbonate polyol), hydroxyl-terminated silicone oil, hydroxyalkyl-terminated silicone oil, and other polymer polyols, but are not limited to the above-listed examples.

[0046] A commonly used isocyanate curing agent is an adduct of polyisocyanate monomers (such as HDI, IPDI, etc.) and polyether diols. The isocyanate curing agent contains at least 3 wt% NCO groups, or more specifically, at least 5 wt% NCO groups. Alternatively, an isocyanate trimer, such as HDI trimer or IPDI trimer, can be added to the above adduct. Isocyanate trimers can also be used directly as the curing agent.

[0047] The solid electrolyte of this invention uses siloxane-modified polyaspartic ester resin as the polymer matrix. The excellent flexibility and high / low temperature resistance of polysiloxane enable the solid electrolyte to exhibit good ionic conductivity at low temperatures. The siloxane-modified polyaspartic ester polymer contains multiple carbonyl and alkoxy structures, exhibiting high polarity and higher ionic conductivity compared to conventional polysiloxanes, while also possessing low impedance and a high electrochemical window. The polysiloxane-modified aspartic polyurea formed by curing the siloxane-modified polyaspartic ester resin with an isocyanate curing agent exhibits good stability.

[0048] The preparation method of the solid electrolyte of the present invention is not particularly limited. For example, one preparation method is as follows: solid lithium salt is added to siloxane-modified polyaspartic acid ester resin, stirred and dispersed evenly, then isocyanate curing agent is added, mixed evenly, and cured to obtain solid electrolyte. For the use of liquid lithium salt, the solid lithium salt, solvent and additives are mixed and dispersed evenly and then directly added to siloxane-modified polyaspartic acid ester resin.

[0049] The technical solution of the present invention will be further described and illustrated below with reference to various embodiments. Unless otherwise specified, the parts mentioned in the following embodiments are parts by weight.

[0050] Examples 1-4 Preparation of Siloxane-Modified Polyaspartic Acid Ester Resin

[0051] Example 1

[0052] aminopropyltrimethoxysilane trimer (in formula (3) above, a = 1, R1, R2, R3, R5 and R6 are all methyl, R7, R8 and R... 10 The molar ratio of propylene (both are propylene) and diethyl maleate is 1:3.3.

[0053] Aminopropyltrimethoxysilane trimer and diethyl maleate were added to a reaction vessel, and the mixture was heated to 80°C and reacted for 72 hours. After the reaction was completed, the product was passed through a short-path evaporator at an evaporation temperature of 110°C and a vacuum of 4 Pa ​​to obtain siloxane-modified polyaspartic acid ester resin, denoted as resin S-1.

[0054] Example 2

[0055] Aminopropyltrimethoxysilane dimer (in formula (3) above, a = 0, R1, R2, R3, R5 and R6 are all methyl, R7, R8 and R... 10 The molar ratio of propylene (both are propylene) and dibutyl maleate is 1:2.1.

[0056] Aminopropyltrimethoxysilane dimer and dibutyl maleate were added to a reaction vessel, and the mixture was heated to 80°C and reacted for 96 hours. After the reaction, the product was passed through a short-path evaporator at 120°C and a vacuum of 6 Pa to obtain siloxane-modified polyaspartic acid ester resin, denoted as resin S-2.

[0057] Example 3

[0058] The molar ratio of aminopropyltrimethoxysilane polymer to diethyl maleate is 1:8.2.

[0059] The structure of aminopropyltrimethoxysilane polymer is as follows:

[0060]

[0061] Aminopropyltrimethoxysilane polymer and diethyl maleate were added to a reaction vessel, and the mixture was heated to 100°C and reacted for 120 hours. After the reaction was completed, the product was passed through a short-path evaporator at an evaporation temperature of 110°C and a vacuum of 5 Pa to obtain siloxane-modified polyaspartic acid ester resin, denoted as resin S-3.

[0062] Example 4

[0063] The molar ratio of aminopropyltrimethoxysilane polymer to diethyl maleate is 1:11.

[0064] The structure of aminopropyltrimethoxysilane polymer is as follows:

[0065]

[0066] Aminopropyltrimethoxysilane polymer and diethyl maleate were added to a reaction vessel, and the mixture was heated to 100°C and reacted for 120 hours. After the reaction, the product was passed through a short-path evaporator at 120°C and a vacuum of 5 Pa to obtain siloxane-modified polyaspartic acid ester resin, denoted as resin S-4.

[0067] Examples 5-12 Preparation of Solid Electrolytes

[0068] Example 5

[0069] The raw material components of the solid electrolyte in this embodiment are composed of resin S-1 from Example 1, liquid lithium hexafluorophosphate, and HDI trimer.

[0070] In the liquid lithium hexafluorophosphate, the solid weight of lithium hexafluorophosphate is 25% of the weight of resin S-1. The preparation method of liquid lithium hexafluorophosphate is as follows: the solid lithium hexafluorophosphate is dissolved by stirring in a solvent containing 10% FEC by volume in a DEC:EC = 1:1 (volume ratio) solvent, and the concentration of lithium hexafluorophosphate is 1 mol / L.

[0071] The molar ratio of NH groups in resin S-1 to NCO groups in the HDI trimer is 1:1.

[0072] Under an argon atmosphere, resin S-1 was added to liquid lithium hexafluorophosphate, stirred thoroughly to dissolve, and then HDI trimer was added and stirred until homogeneous to obtain a precursor solution.

[0073] Solid electrolyte preparation: Under argon atmosphere, 100 μL of the above precursor solution was dropped onto both sides of the battery separator to completely wet the separator. After the battery was assembled and packaged, the battery was left to stand at room temperature for 72 hours to obtain the solid electrolyte.

[0074] Example 6

[0075] The difference between this embodiment and Embodiment 5 is that in Embodiment 5, the solid weight of lithium hexafluorophosphate was adjusted from 25% to 15% of the weight of resin S-1. The remaining steps remain unchanged.

[0076] Example 7

[0077] The difference between this embodiment and Embodiment 5 is that in Embodiment 5, the solid weight of lithium hexafluorophosphate was adjusted from 25% to 40% of the weight of resin S-1. The remaining steps remain unchanged.

[0078] Example 8

[0079] The raw material components of the solid electrolyte in this embodiment consist of resin S-2 from Example 2, liquid lithium hexafluorophosphate, and isocyanate curing agent.

[0080] The weight of solid lithium hexafluorophosphate in liquid lithium hexafluorophosphate is 30% of the weight of resin S-2. The preparation method of liquid lithium hexafluorophosphate is as follows: solid lithium hexafluorophosphate is dissolved by stirring in a solvent containing 5% FEC by volume in a DEC:EC = 1:1 (volume ratio) solvent, and the concentration of lithium hexafluorophosphate is 2 mol / L.

[0081] The molar ratio of NH groups in resin S-2 to NCO groups in the isocyanate curing agent is 1.03:1.

[0082] The isocyanate curing agent has an NCO group content of 10.7 wt%. The isocyanate curing agent is composed of an adduct of HDI and polyether 330N (NCO group content 5.2 wt%) and an HDI trimer.

[0083] Under an argon atmosphere, resin S-2 was added to liquid lithium hexafluorophosphate, stirred thoroughly to dissolve, and then isocyanate curing agent was added and stirred evenly to obtain a precursor solution.

[0084] Solid electrolyte preparation: Under argon atmosphere, 100 μL of the above precursor solution was dropped onto both sides of the battery separator to completely wet the separator. After the battery was assembled and packaged, the battery was left to stand at room temperature for 72 hours to obtain the solid electrolyte.

[0085] Example 9

[0086] The difference between this embodiment and Embodiment 8 is that in Embodiment 8, resin S-2 in Embodiment 2 is replaced with an equal weight of resin S-3 in Embodiment 3. The remaining steps remain unchanged.

[0087] Example 10

[0088] The difference between this embodiment and Embodiment 8 is that in Embodiment 8, resin S-2 in Embodiment 2 is replaced with an equal weight of resin S-4 from Embodiment 4. The remaining steps remain unchanged.

[0089] Comparative Example 1

[0090] The difference between this comparative example and Example 8 is that in Example 8, resin S-2 in Example 2 was replaced with an equal weight of resin S-5. The remaining steps remained unchanged.

[0091] The preparation method of resin S-5 is as follows: aminopropyltrimethoxysilane polymer and diethyl maleate are added to a reaction vessel, and the temperature is raised to 100℃ and reacted for 120 hours. After the reaction is completed, the product is passed through a short-path evaporator at an evaporation temperature of 110℃ and a vacuum degree of 5Pa to obtain siloxane-modified polyaspartic acid ester resin, denoted as resin S-5.

[0092] The molar ratio of aminopropyltrimethoxysilane polymer to diethyl maleate is 1:5.3.

[0093] The structure of aminopropyltrimethoxysilane polymer is as follows:

[0094]

[0095] Comparative Example 2

[0096] The difference between this comparative example and Comparative Example 1 is that in Comparative Example 1, resin S-5 was replaced with an equal weight of resin S-6. The remaining steps remained unchanged.

[0097] The molar ratio of alkoxy-terminated polydimethylsiloxane to diethyl maleate is 1:2.2.

[0098] The preparation method of resin S-6 is as follows: Alkoxy-terminated polydimethylsiloxane and diethyl maleate are added to a reaction vessel, and the mixture is heated to 90°C and reacted for 120 hours. After the reaction, the product is passed through a short-path evaporator at an evaporation temperature of 110°C and a vacuum degree of 5 Pa to obtain siloxane-modified polyaspartic acid ester resin, denoted as resin S-6.

[0099] The structure of alkoxy-terminated polydimethylsiloxane is as follows:

[0100]

[0101] Comparative Example 3

[0102] The difference between this comparative example and Example 8 is that in Example 8, resin S-2 in Example 2 was replaced with an equal weight of polyethylene glycol-modified polyaspartic acid ester resin. All other steps remained unchanged.

[0103] The preparation method of polyethylene glycol modified polyaspartic acid ester resin is as follows: Bis-terminated primary amino polyethylene glycol (number average molecular weight 800) and diethyl maleate are added to a reaction vessel at a molar ratio of 1:2.2. The mixture is heated to 100℃ and reacted for 120 hours. After the reaction, the product is passed through a short-path evaporator at an evaporation temperature of 110℃ and a vacuum degree of 5 Pa to obtain polyethylene glycol modified polyaspartic acid ester resin.

[0104] Example 11

[0105] The difference between this embodiment and Embodiment 8 is that in Embodiment 8, solid lithium hexafluorophosphate is replaced with an equal weight of lithium bis(fluorosulfonyl)imide. The remaining steps remain unchanged.

[0106] Example 12

[0107] The difference between this embodiment and Embodiment 8 is that in Embodiment 8, solid lithium hexafluorophosphate is replaced with an equal weight of lithium bis(trifluoromethanesulfonyl)imide. The remaining steps remain unchanged.

[0108] Ionic conductivity testing method: The test battery is assembled according to the negative electrode battery case, stainless steel gasket, solid electrolyte, stainless steel gasket, and positive electrode battery case. The interfacial impedance R is obtained by AC impedance spectroscopy test at 30℃ and 60℃ using an electrochemical workstation. The ionic conductivity is obtained by using the formula σ=L / RS, where L is the electrolyte thickness and S is the area of ​​the stainless steel gasket.

[0109] Interfacial impedance testing method: The test battery is assembled according to the following steps: negative electrode battery case, nickel mesh, lithium metal sheet, solid electrolyte, lithium metal sheet, nickel mesh, and positive electrode battery case. The interfacial impedance is obtained by AC impedance spectroscopy testing using an electrochemical workstation.

[0110] Electrochemical window testing method: The test battery is assembled according to the negative electrode battery case, nickel mesh, lithium metal sheet, electrolyte, stainless steel gasket, and positive electrode battery case. The electrochemical window is obtained by linear scanning voltammetry using an electrochemical workstation.

[0111] The results are shown in Table 1 below.

[0112] Table 1

[0113]

[0114] As shown in Table 1, the solid electrolyte of the present invention uses polysiloxane-modified aspartic acid ester resin with a specific structure. Compared with polyethylene glycol-modified aspartic acid ester resin, the ionic conductivity is similar, but the interfacial impedance is significantly lower and the electrochemical window is also higher.

[0115] As described above, the basic principles, main features, and advantages of the present invention have been shown and described. Those skilled in the art should understand that the present invention is not limited to the above embodiments, which are merely preferred embodiments and should not be construed as limiting the scope of the invention. All equivalent changes and modifications made in accordance with the scope of the patent and the description should still fall within the scope of the present invention. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A polysiloxane-modified aspartic acid ester resin, characterized in that, It has the structure shown in equation (1) below. Among them, R1, R2, R3, R5, R6, R 11 R 12 R 13 R 14 R 15 and R 16 Individually selected from C1-C4 alkyl groups, R7, R8 and R 10 R4 is selected from C1-C4 alkyl or C1-C4 alkoxy, R9 is selected from C1-C4 alkyl, C1-C4 alkoxy or the structure shown in formula (2) below, a≥0, b≥0, a+b≤10, b / (a+b)≤0.

5. Among them, R 17 Selected from C1-C6 divalent alkyl groups, R 18 and R 19 The individual is selected from C1-C4 alkyl groups.

2. The polysiloxane-modified aspartic acid ester resin according to claim 1, characterized in that, The values ​​of a and b satisfy: b / (a+b)≤0.

3.

3. The polysiloxane-modified aspartic acid ester resin according to claim 1, characterized in that, The values ​​of a and b satisfy: b = 0, 0 ≤ a ≤ 7.

4. The polysiloxane-modified aspartic acid ester resin according to claim 1, characterized in that, R1, R2, R3, R5 and R6 are individually selected from methyl or ethyl.

5. The polysiloxane-modified aspartic acid ester resin according to claim 1, characterized in that, The polysiloxane-modified aspartic acid ester resin is obtained by Michael addition reaction of the poly-primary amine polysiloxane corresponding to the structure shown in formula (1) with dialkyl maleate or dialkyl fumarate.

6. A solid electrolyte, characterized in that, The raw material components include: the siloxane-modified polyaspartic acid ester resin according to any one of claims 1-5, lithium salt, and isocyanate curing agent.

7. The solid electrolyte according to claim 6, characterized in that, The weight of the lithium salt is 5-50% of the weight of the siloxane-modified polyaspartic acid ester resin.

8. The solid electrolyte according to claim 6 or 7, characterized in that, The lithium salt is selected from one or a combination of two or more of lithium hexafluorophosphate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium tetrafluoroborate, lithium perchlorate, lithium difluorophosphate, lithium difluorobis(oxalate)phosphate, lithium bis(difluorosulfonyl)imide, lithium bis(oxalate)borate, lithium difluorooxalateborate, lithium nitrate, lithium trifluoromethanesulfonate, and tris(trifluoromethanesulfonyl)methyl lithium.

9. The solid electrolyte according to claim 6, characterized in that, The molar ratio of NH groups in the siloxane-modified polyaspartic acid ester resin to NCO groups in the isocyanate curing agent is 0.8-1.2:

1.

10. The solid electrolyte according to claim 6, characterized in that, The isocyanate curing agent is selected from one or a combination of two or more of HDI trimer, HDI biuret, HDI diuret, HDI urethane, HDI urethane, IPDI trimer, IPDI urethane, IPDI urethane, CHDI urethane, HMDI, IPDI and CHDI.

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