Solid-state electrolyte, solid-state battery pole piece and preparation method and application thereof

Abstract

The application provides a solid-state electrolyte, a solid-state battery pole piece and a preparation method and application thereof, the solid-state electrolyte comprises a polymer, and the polymer comprises carbonate groups and catechol structures.The solid-state electrolyte has good ionic conductivity and viscosity, can be uniformly dispersed in the solid-state battery pole piece, so that the solid-state battery pole piece does not need to add a binder and an ion-conducting additive, thereby the content ratio of non-active substances in the solid-state battery pole piece can be reduced, and the solid-state battery pole piece has excellent electrochemical performance, mechanical performance and processability.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of batteries, and relates to a solid-state electrolyte, a solid-state battery pole piece and a preparation method and application thereof. BACKGROUND

[0002] Since the commercialization of lithium ion batteries, the energy density has been continuously improved, and the energy density of 300 wh / kg has been achieved in the industry at present. However, the energy density of lithium ion batteries still needs to be further improved, and the frequent fire incidents of liquid lithium batteries also put forward requirements for the safety of future batteries. The strategy of taking into account high energy and high safety is to go to all-solid-state. At present, the electrolyte disclosed in the prior art is generally located between the positive and negative pole pieces and plays the role of replacing the separator and electrolyte in the liquid lithium battery. However, there are few reports on the solid-state electrolyte used in the internal positive pole of the solid-state battery. Therefore, the ion transmission in the internal positive pole is still one of the key technologies and bottlenecks restricting the development of solid-state batteries.

[0003] Since the most critical part of the lithium battery positive pole is the active material, in order to form an electronic conduction network in the electrode, a conductive agent needs to be added, and in order to bond the powder particles and make the electrode mechanically complete, a certain amount of binder also needs to be added. The commonly added binder is ion and electron insulating, which will hinder the conduction of lithium ions and reduce the performance of the battery. As one of the most commonly used binders for lithium ion batteries, polyvinylidene fluoride (PVDF) is a non-polar chain-like high molecular crystalline polymer with high thermal stability, good chemical stability and easy dispersion. However, the interaction between PVDF and the electrode material is weak van der Waals force, and the adhesion is weak. The use of a binder with strong functional groups (such as -OH, -COOH) can enhance the adhesion.

[0004] At the same time, in the solid-state lithium battery positive pole, unlike the electrolyte in the liquid lithium battery which can penetrate into the positive pole to form an ion channel, the positive and negative poles and the electrolyte of the solid-state lithium battery are mostly in a layer-by-layer stacked state. Even the in-situ polymerized solid-state polymer electrolyte can only be used in the case of low active material loading due to the limitations of polymer viscosity and flowability. Therefore, ion additives need to be added during the preparation of the solid-state positive pole to ensure the ion conduction in the internal positive pole, which undoubtedly increases the proportion of non-active materials in the battery and the cost.

[0005] Solid-state battery electrolytes generally include organic solid-state electrolytes and inorganic solid-state electrolytes. Although the existing inorganic solid-state electrolytes have high ionic conductivity, they tend to agglomerate when added as ionic additives to the positive electrode. The point contact between the inorganic electrolyte and the positive active particles results in low electrolyte utilization. A large amount of addition is usually required to achieve good lithium ion transmission effect, and high addition amount reduces the energy density of the battery. The polymer solid-state electrolyte can be uniformly dispersed in the positive electrode. The commonly used PEO-based polymer electrolyte realizes Li + migration. In such polymer electrolytes, the lithium salt dissolved in the electrolyte cannot be completely dissociated, which easily causes ion accumulation, thereby reducing the Li + migration rate. Therefore, the ionic conductivity of the PEO-based solid-state electrolyte is generally low, and it basically works at a high temperature (60℃). The electrochemical window of the PEO-based polymer electrolyte is also low, which limits its application range.

[0006] Therefore, it is necessary to provide a solid-state electrolyte which has different lithium ion transmission mechanisms and strong functional groups, so as to achieve high room temperature ionic conductivity and high viscosity. In addition, it should also have good dispersibility in the positive electrode sheet, good wettability with the current collector and the positive electrode material, and other advantages. SUMMARY

[0007] The purpose of the present application is to provide a solid-state electrolyte, a solid-state battery electrode sheet and a preparation method and application thereof. The solid-state electrolyte has good ionic conductivity, can be uniformly dispersed in the solid-state battery electrode sheet, and has high viscosity, can be used as a binder, reduces the content of non-active substances in the solid-state battery electrode sheet, and solves the problem of battery performance degradation caused by the need for additional non-active substances in the solid-state battery electrode sheet.

[0008] To achieve this purpose, the present application adopts the following technical solutions:

[0009] In a first aspect, the present application provides a solid-state electrolyte, which comprises a polymer, and the polymer comprises a carbonate group and a catechol structure.

[0010] The solid-state electrolyte of the present application comprises a polymer, and the polymer comprises a carbonate group, which is a polycarbonate-based polymer. The polar carbonate group [-O-(C=O)-O-] can promote the ionization of lithium salt, and the carbonyl group (-C=O) in it and the free Li + between them can complex and decomplex, thereby promoting the Li + migration, and can construct an ion channel in the solid-state battery electrode sheet. Therefore, the polycarbonate-based solid-state electrolyte has high ionic conductivity, and the specific value can reach 10 -4The solid-state electrolyte has a room temperature ionic conductivity of about 10-3 S / cm or so, and can be uniformly dispersed in a solid-state battery electrode sheet; however, the polycarbonate-based polymer is non-adhesive, and thus the present application introduces a catechol structure into the solid-state electrolyte, so that the solid-state electrolyte not only has a relatively high room temperature ionic conductivity, but also has a relatively high adhesion, so that the solid-state electrolyte can simultaneously play a role of a binder in the solid-state battery electrode sheet to avoid the use of a conventional binder for ion and electron insulation, and improve the performance of the solid-state battery; in addition, the solid-state electrolyte is also applicable to different battery systems, and has high universality.

[0011] The catechol structure of the present application refers to a structure in which a phenolic hydroxyl group is present at positions 3 and 4 of a benzene ring.

[0012] Preferably, the solid-state electrolyte further comprises a lithium salt.

[0013] Preferably, the carbonate group is located in a cyclic structure.

[0014] Preferably, the precursors for polymerization of the polymer comprise a carbonate monomer, a catechol monomer, a lithium salt, and an initiator.

[0015] The preparation method of the solid-state electrolyte of the present application is simple, and only needs to mix the above-mentioned precursors and then stir and heat (UV light) to obtain.

[0016] Preferably, the molar ratio of the catechol monomer to the lithium salt is (0.8-1.8):1, for example, it can be 0.8:1, 0.9:1, 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1 or 1.8:1, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0017] Preferably, the molar ratio of the catechol monomer to the carbonate monomer is (15-23):(77-85), for example, it can be 15:85, 20:80 or 23:77, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0018] Preferably, the molar ratio of the carbonate monomer to the lithium salt is (5-20):1, for example, it can be 5:1, 8:1, 10:1, 15:1 or 20:1, but is not limited to the listed values, and other values not listed in the value range are also applicable, preferably (5-10):1.

[0019] In order to avoid the need for a solvent removal step when the precursor is dissolved in a solvent, the present application uses a solvent-free form to carry out the reaction, but the catechol monomer is not soluble in the carbonate monomer, and the catechol monomer needs to be dissolved in the carbonate monomer to polymerize with it to form a polymer containing catechol structure, therefore, the present application adds lithium salt to the raw materials, lithium salt is an ionic salt, catechol monomer includes double bond, both are solid at room temperature, after blending, due to intermolecular forces (hydrogen bond), a co-solvent structure is formed, similar to room temperature ionic liquid, which can form a uniform transparent solution with the liquid carbonate monomer, so that the catechol monomer can be dissolved smoothly, therefore, the present application limits the molar ratio between the catechol monomer, lithium salt and carbonate monomer to be within a reasonable range to dissolve the catechol monomer.

[0020] Preferably, the amount of initiator added is 1-5wt% of the total weight of carbonate monomer, catechol monomer and lithium salt, for example, it can be 1wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 4.5wt% or 5wt%, but is not limited to the listed values, other values not listed within the value range are also applicable, preferably 1wt%.

[0021] The amount of initiator added in the present application will affect the polymerization degree of the solid electrolyte, if the content of initiator is too low, it cannot guarantee the effective polymerization of the monomer, thereby affecting the performance of the solid electrolyte.

[0022] Preferably, the carbonate monomer includes a chain carbonate monomer and / or a cyclic carbonate monomer, preferably a cyclic carbonate monomer.

[0023] Preferably, the carbonate monomer includes a carbonate group and a carbon-carbon unsaturated bond.

[0024] Preferably, the chain carbonate monomer includes a diallyl carbonate and / or a methyl vinyl carbonate.

[0025] Preferably, the cyclic carbonate monomer includes a vinyl ethylene carbonate and / or a vinylene carbonate, preferably a vinyl ethylene carbonate.

[0026] Preferably, the catechol monomer includes a catechol structure and a carbon-carbon unsaturated bond.

[0027] The catechol monomer and the cyclic carbonate monomer in the present application both include a carbon-carbon unsaturated bond, therefore, the solid electrolyte in the present application is polymerized by a carbon-carbon unsaturated bond to obtain a polymer.

[0028] Preferably, the structure of the catechol monomer is:

[0029]

[0030] wherein R1 is selected from a C1-C6 hydrocarbyl group, and R2 is selected from a C2-C6 hydrocarbyl group, and R2 includes at least one carbon-carbon unsaturation.

[0031] Exemplarily, R1 is selected from any one of methylene, ethylene or isopropylidene.

[0032] Exemplarily, R2 is selected from any one of vinyl, allyl or 1-alkenyl butyl.

[0033] Preferably, the raw material for preparing the catechol monomer includes dopamine hydrochloride and an acyl chloride compound.

[0034] Preferably, the acyl chloride compound contains an unsaturated carbon-carbon bond.

[0035] The catechol monomer of the present application uses dopamine hydrochloride as a raw material, and an acyl chloride compound containing a carbon-carbon unsaturated bond is used to introduce a double bond into the catechol monomer. The preparation method of the catechol monomer is simple, which only needs to mix and separate the raw materials in a solvent. The molar amount of the acyl chloride compound is greater than that of dopamine hydrochloride, and the molar ratio of dopamine hydrochloride to the acyl chloride compound is preferably 1:(3-7), for example, it can be 1:3, 1:4, 1:5, 1:6 or 1:7, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0036] Preferably, the acyl chloride compound includes any one of acryloyl chloride, but-3-enoyl chloride or 4-pentenoyl chloride, or a combination of at least two thereof, and a typical but non-limiting combination includes a combination of acryloyl chloride and but-3-enoyl chloride, or a combination of acryloyl chloride and 4-pentenoyl chloride.

[0037] The initiator of the present application includes a thermal initiator or a photoinitiator, and exemplarily includes azobisisobutyronitrile. The lithium salt includes any one of LiTFSI, LiBF4 or LIBOB, or a combination of at least two thereof.

[0038] In a second aspect, the present application provides a solid-state battery electrode sheet, which includes an active material layer, and the active material layer includes an active material, a conductive agent and a solid-state electrolyte as described in the first aspect.

[0039] The solid-state battery pole piece of the present application does not need to add additional binder and ion-conducting additive, and only needs to add the solid-state electrolyte with a special structure in the first aspect on the basis of the active material and the conductive agent. The presence of the solid-state electrolyte makes the solid-state battery pole piece have excellent mechanical properties and processability, and the viscosity can be comparable to the commonly used PVDF binder. Therefore, the solid-state battery pole piece of the present application can only include active material, conductive agent and a small amount of solid-state electrolyte, which greatly reduces the amount of non-active substances in the solid-state battery pole piece.

[0040] Preferably, the content of the solid-state electrolyte in the solid-state battery pole piece is 8-10wt%, for example, it can be 8wt%, 9wt% or 10wt%, but is not limited to the listed values, and other unlisted values within the value range are also applicable.

[0041] The addition amount of the solid-state electrolyte of the present application is small, which can improve the proportion of active material in the solid-state battery pole piece on the basis of ensuring viscosity and high room temperature ionic conductivity.

[0042] Preferably, the content of the active material in the solid-state battery pole piece is 80-82wt%, for example, it can be 80wt%, 81wt% or 82wt%, but is not limited to the listed values, and other unlisted values within the value range are also applicable.

[0043] The present application does not make specific limitations on the types of active material and conductive agent, and the skilled person can make reasonable choices according to the needs; for example, the active material includes any one or a combination of at least two of lithium iron phosphate, lithium manganese phosphate or lithium nickel cobalt manganese oxide; the conductive agent includes any one or a combination of at least two of conductive carbon black, conductive carbon nanotube or graphene, and a typical but non-limiting combination includes a combination of conductive carbon black and conductive carbon nanotube, or a combination of graphene and conductive carbon black.

[0044] In a third aspect, the present application provides a preparation method of the solid-state battery pole piece according to the second aspect, which comprises the following steps:

[0045] Mixing the solvent and the solid-state electrolyte according to the first aspect to obtain a solid-state electrolyte solution, then adding the active material and the conductive agent to the solid-state electrolyte solution and mixing to obtain a slurry, and then coating, drying and rolling the slurry to obtain the solid-state battery pole piece.

[0046] In a fourth aspect, the present application provides a solid-state battery, which comprises the solid-state battery pole piece according to the second aspect.

[0047] Compared with the prior art, the present application has the following beneficial effects:

[0048] (1) The solid-state electrolyte provided by the application is a polycarbonate-based polymer electrolyte containing catechol structure, therefore, the solid-state electrolyte not only has high room temperature ionic conductivity, but also has high viscosity, can replace the binder in the solid-state battery pole piece, avoids the addition of the binder in the solid-state battery pole piece, and thus can significantly improve the performance of the solid-state battery;

[0049] (2) The solid-state battery pole piece provided by the application does not need to add additional binder and ion-conducting additive, only needs to add the solid-state electrolyte provided by the application on the basis of the active material and the conductive agent, the viscosity of the solid-state electrolyte can be comparable to the commonly used PVDF binder, so that the solid-state battery pole piece has excellent mechanical properties and processability. BRIEF DESCRIPTION OF DRAWINGS

[0050] Figure 1 The impedance graph of the stainless steel symmetrical battery made of the electrolyte film of the solid-state electrolyte described in Embodiment 1 of the application is shown in the figure;

[0051] Figure 2 The scanning electron microscope graph of the solid-state battery pole piece described in Application Example 1 of the application is shown in the figure;

[0052] Figure 3 The optical image of the solid-state battery pole piece described in Application Example 1 of the application is shown in the figure;

[0053] Figure 4 The cycle performance graph of the LFP-Li solid-state battery assembled by the solid-state battery pole piece described in Application Example 1 of the application is shown in the figure;

[0054] Figure 5 The peeling force and displacement curve graph of the solid-state battery pole piece described in Application Example 1 of the application is shown in the figure;

[0055] Figure 6 The optical image of the solid-state battery pole piece described in Application Example 1 of the application after peeling is shown in the figure;

[0056] Figure 7 The optical image of the adhesive tape after the surface of the solid-state battery pole piece described in Application Example 1 of the application is peeled by the adhesive tape is shown in the figure. DETAILED DESCRIPTION

[0057] The technical solutions of the application will be further described through specific embodiments. Those skilled in the art should understand that the embodiments are only used to help understand the application and should not be regarded as specific limitations on the application.

[0058] Embodiment 1

[0059] The embodiment provides a solid-state electrolyte, the solid-state electrolyte is a polymer, including a carbonate group and a catechol structure, the carbonate group is located in a cyclic structure;

[0060] The raw materials for polymerizing the solid-state electrolyte include carbonate monomers, catechol monomers, lithium salts, and initiators, the molar ratio of the catechol monomers to the carbonate monomers is 15:85, the molar ratio of the carbonate monomers to the lithium salts is 10:1, and the addition amount of the initiators is 1 wt% of the total weight of the carbonate monomers, the catechol monomers, and the lithium salts;

[0061] The solid-state electrolyte is PDV, which is obtained by mixing carbonate monomers, catechol monomers, lithium salts, and initiators to obtain a solid-state electrolyte precursor solution, and then performing heating polymerization; characteristic peaks are characterized by Fourier transform infrared spectroscopy, and 1780 cm -1 is a C=O characteristic peak, 3380 cm -1 is an -OH and N-H characteristic peak (because 3380 cm -1 is a characteristic peak of catechol monomers, 1780 cm -1 is a characteristic peak of carbonate monomers, and the fact that PDV has both of the above characteristic peaks indicates that PDV is successfully prepared);

[0062] The carbonate monomers are vinyl ethylene carbonate (VEC), the catechol monomers are DAA, the raw materials for preparation include dopamine hydrochloride and acryloyl chloride, the lithium salts are LiTFSI, and the initiators are azobisisobutyronitrile (AIBN), and the structural formulas of the DAA, the vinyl ethylene carbonate (VEC), and the PDV are as follows:

[0063]

[0064] The m and n of the PDV are determined by the content of the initiators;

[0065] The impedance diagram of the stainless steel symmetric battery prepared from the solid-state electrolyte prepared in this embodiment is as shown in FIG. 2. Figure 1

[0066] Example 2

[0067] The solid-state electrolyte provided in this embodiment is a polymer, which includes carbonate groups and catechol structures, and the carbonate groups are located in a cyclic structure;

[0068] The raw materials for polymerizing the solid-state electrolyte include carbonate monomers, catechol monomers, lithium salts, and initiators, the molar ratio of the catechol monomers to the carbonate monomers is 23:77, the molar ratio of the carbonate monomers to the lithium salts is 5:1, and the addition amount of the initiators is 1 wt% of the total weight of the carbonate monomers, the catechol monomers, and the lithium salts;

[0069] ​The solid-state electrolyte is PDV, a solid-state electrolyte precursor solution is obtained by mixing a carbonate monomer, a catechol monomer, a lithium salt and an initiator, and then photoinitiation is performed to obtain a polymer electrolyte; characteristic peaks are characterized by Fourier transform infrared spectroscopy, 1780 cm -1 is a C=O characteristic peak, 3380 cm -1 is an -OH and N-H characteristic peak;

[0070] The carbonate monomer is vinyl ethylene carbonate (VEC), the catechol monomer is DAA, the raw materials for preparation include dopamine hydrochloride and acryloyl chloride, the lithium salt is LiClO4, and the initiator is a photoinitiator. The structures of the DAA, the vinyl ethylene carbonate (VEC) and the PDV are as follows:

[0071]

[0072] The m and n of the PDV are determined by the content of the initiator.

[0073] Example 3

[0074] The present embodiment provides a solid-state electrolyte, which is a polymer and includes a carbonate group and a catechol structure, wherein the carbonate group is located in a cyclic structure.

[0075] The raw materials for polymerizing the solid-state electrolyte include a carbonate monomer, a catechol monomer, a lithium salt and an initiator, the molar ratio of the catechol monomer to the carbonate monomer is 19:81, the molar ratio of the carbonate monomer to the lithium salt is 5:1, and the addition amount of the initiator is 1wt% of the total weight of the carbonate monomer, the catechol monomer and the lithium salt.

[0076] The solid-state electrolyte is obtained by mixing a carbonate monomer, a catechol monomer, a lithium salt and an initiator to obtain a solid-state electrolyte precursor solution, and then performing thermal polymerization; characteristic peaks are characterized by Fourier transform infrared spectroscopy, 1780 cm -1 is a C=O characteristic peak, 3380 cm -1 is an -OH and N-H characteristic peak;

[0077] The carbonate monomer is vinyl ethylene carbonate (VEC); the catechol monomer is different from DAA in that the R2 group of DAA is a vinyl group, and the allyl group in the present embodiment; the raw materials for preparation include dopamine hydrochloride and but-3-enoyl chloride; the lithium salt is LiTFSI, and the initiator is azobisisobutyronitrile (AIBN).

[0078] Example 4

[0079] The present example provides a solid-state electrolyte, which is the same as example 1 except that the molar ratio of the carbon ester-based monomer to the lithium salt is 7.5:1.

[0080] Example 5

[0081] The present example provides a solid-state electrolyte, which is the same as example 1 except that the molar ratio of the carbon ester-based monomer to the lithium salt is 5:1.

[0082] Example 6

[0083] The present example provides a solid-state electrolyte, which is the same as example 1 except that the molar ratio of the catechol-based monomer to the carbon ester-based monomer is 10:90.

[0084] Example 7

[0085] The present example provides a solid-state electrolyte, which is the same as example 1 except that the molar ratio of the carbon ester-based monomer to the lithium salt is 3:1.

[0086] Example 8

[0087] The present example provides a solid-state electrolyte, which is the same as example 1 except that the molar ratio of the carbonate-based monomer to the lithium salt is 15:1.

[0088] Example 9

[0089] The present example provides a solid-state electrolyte, which is the same as example 1 except that the amount of the initiator added is 0.3 wt% of the total weight of the carbonate-based monomer, the catechol-based monomer, and the lithium salt.

[0090] Example 10

[0091] The present example provides a solid-state electrolyte, which is the same as example 1 except that the amount of the initiator added is 6 wt% of the total weight of the carbonate-based monomer, the catechol-based monomer, and the lithium salt.

[0092] Comparative Example 1

[0093] The present comparative example provides a solid-state electrolyte, which is the same as example 1 except that the catechol-based monomer is replaced with ethylene vinyl ethylene carbonate (VEC) in an equimolar amount, and the structure of the solid-state electrolyte is changed to adapt.

[0094] The solid-state electrolyte provided by the above examples and comparative examples is in a solid-state electrolyte precursor solution state before drying. 10 μL of the solid-state electrolyte precursor solution is dropped on a stainless steel sheet (the stainless steel sheet is placed in a positive electrode shell), and then a 30 μm-thick commercially available cellulose separator is arranged. 20 μL of the solid-state electrolyte precursor solution is dropped on the surface of the separator, and a stainless steel, a spring and a negative electrode shell are sequentially covered to obtain a stainless steel-stainless steel pair battery. After heating at 80 ℃ for 24 h, the impedance of the stainless steel-stainless steel pair battery is tested at room temperature (25 ℃) using an electrochemical workstation. Then, the electrolyte membrane is taken out to measure the thickness, and the room temperature ionic conductivity of the solid-state electrolyte provided by the above examples and comparative examples is calculated, and the results are shown in Table 1 below.

[0095] Table 1

[0096]

[0097]

[0098] Application Example 1

[0099] The application example provides a solid-state battery electrode sheet, and the active material layer of the solid-state battery electrode sheet comprises 80 wt% of lithium iron phosphate, 10 wt% of conductive carbon black (AB) and 10 wt% of the solid-state electrolyte described in Example 1.

[0100] The preparation method of the solid-state battery electrode sheet comprises:

[0101] N-methyl pyrrolidone and the solid-state electrolyte are mixed to obtain a solid-state electrolyte solution. Lithium iron phosphate and conductive carbon black are added to the solid-state electrolyte solution according to the formula amount and mixed to obtain a slurry. After the slurry is coated on one side of a carbon-coated aluminum foil, the solid-state battery electrode sheet is obtained.

[0102] The scanning electron microscope image of the solid-state battery electrode sheet described in the application example is shown in FIG. 1, the optical image is shown in FIG. 2, the cycle performance graph after the battery is made is shown in FIG. 3, the peeling force and displacement curve graph is shown in FIG. 4, the optical image after peeling is shown in FIG. 5, the optical image of the adhesive tape after the surface of the adhesive tape is peeled is shown in FIG. 6. Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7

[0103] Application Examples 2-10 are the same as Application Example 1, except that the solid-state electrolyte used in each of the application examples corresponds to the solid-state electrolyte described in Examples 2-10, respectively.

[0104] Application Example 11

[0105] ​​​​​​The application example provides a solid-state battery pole piece, and the active material layer of the solid-state battery pole piece is the same as that of the application example 1 except that the content of lithium iron phosphate is 81wt%, the content of conductive carbon black (AB) is 10wt%, and the content of the solid-state electrolyte described in the application example 1 is 9wt%.

[0106] Application example 12

[0107] The application example provides a solid-state battery pole piece, and the active material layer of the solid-state battery pole piece is the same as that of the application example 1 except that the content of lithium iron phosphate is 82wt%, the content of conductive carbon black (AB) is 10wt%, and the content of the solid-state electrolyte described in the application example 1 is 8wt%.

[0108] Application example 13

[0109] The application example provides a solid-state battery pole piece, and the active material layer of the solid-state battery pole piece is the same as that of the application example 1 except that the content of lithium iron phosphate is 90wt%, the content of conductive carbon black (AB) is 5wt%, and the content of the solid-state electrolyte described in the application example 1 is 5wt%.

[0110] Application example 14

[0111] The application example provides a solid-state battery pole piece, and the active material layer of the solid-state battery pole piece is the same as that of the application example 1 except that the content of lithium iron phosphate is 80wt%, the content of conductive carbon black (AB) is 5wt%, and the content of the solid-state electrolyte described in the application example 1 is 15wt%.

[0112] Comparative application example 1

[0113] The comparative application example provides a solid-state battery pole piece, and the active material layer of the solid-state battery pole piece is the same as that of the application example 1 except that the solid-state electrolyte described in the comparative example 1 is used.

[0114] Comparative application example 2

[0115] The comparative application example provides a solid-state battery pole piece, and the solid-state battery pole piece is the same as that of the application example 1 except that the solid-state electrolyte described in the application example 1 is replaced by PVDF in equal mass.

[0116] Cycle performance test: the solid-state battery pole pieces described in the above application examples and comparative examples are assembled into full solid-state batteries with solid-state electrolyte and lithium negative electrode, and the cycle performance is tested under the condition of 0.5C charging and discharging at 25 DEG C, and the capacity retention rate after 50 cycles and 500 cycles is shown in Table 2.

[0117] 180° peeling performance test: the solid-state battery pole piece described in the above application examples and comparative application examples was cut into a sample of 30 mm x 10 mm size, 3M strong double-sided tape with a width of 10 mm was used to tightly paste the current collector surface of the solid-state battery pole piece on an aluminum plate with a thickness of 1 mm, a pressure-sensitive tape with a width of 10 mm and a length of 40 mm was pasted on the side of the solid-state battery pole piece coated with the active material layer, and the remaining pressure-sensitive tape was pasted on a paper strip of appropriate size to facilitate the clamping of the test fixture; a 200g standard weight was used to roll back and forth on the surface of the pressure-sensitive tape for 10 times with the same force, and an Instron3365 universal material testing machine (tension mode, 10N sensor) was used to clamp the aluminum plate and the remaining part of the paper strip with the upper and lower clamps, respectively, at room temperature of 25°C, and the peeling strength of the obtained solid-state battery pole piece was as shown in Table 2.

[0118] The "-" in the following table represents that the prepared battery does not meet the corresponding cycle.

[0119] Table 2

[0120]

[0121]

[0122] From Table 1 and Table 2, it can be seen that:

[0123] (1) The solid-state electrolyte provided by the present application has high room temperature ionic conductivity and good adhesion, and can significantly improve the performance of the solid-state battery when added to the solid-state battery pole piece; as can be seen from application example 1 and comparative application examples 1-2, although comparative application example 1 has ionic conductivity, it has no adhesion and cannot be prepared into a pole piece, and the use of a conventional binder in comparative application example 2 results in low specific capacity and large polarization of the battery, and the battery cannot meet the corresponding cycle, while the solid-state electrolyte provided by the present application has high room temperature ionic conductivity and adhesion, and combines the advantages of conventional binders and conventional solid-state electrolytes, so it can be used as a binder and a solid-state electrolyte in the positive electrode, and the present application Figure 6 and 7 It can be seen that the adhesive tape does not peel off the active material after peeling off the surface of the solid-state battery pole piece, which proves that the adhesion of the solid-state electrolyte described in the present application is good, and the solid-state battery pole piece has good mechanical properties.

[0124] (2) from application example 1 and application examples 6-8, the ionic conductivity of the solid-state electrolyte in application example 6 is high, but the catechol group content is low, the adhesion is insufficient, the active material will fall off, and cannot be used normally, so it cannot reach the corresponding cycle, in example 7, too much lithium salt is added, which cannot be completely dissociated, in example 8, too little lithium salt is added, the catechol monomer is not completely dissolved, the adhesion group content in the solid-state electrolyte is low, the adhesion is poor, the active material will fall off, and the corresponding cycle cannot be reached, therefore, the molar ratio of catechol monomer, lithium salt and carbonate monomer will affect the battery performance; from application example 1 and application examples 9-10, the initiator will affect the polymerization degree of the solid-state electrolyte, therefore, when the initiator is too little, the polymerization degree is reduced, the active material will fall off, and the corresponding cycle cannot be reached, and too much initiator will not obviously affect the performance, but will cause waste of raw materials; from application example 1 and application examples 13-14, in the solid-state electrolyte pole piece, when the amount of solid-state electrolyte added is too little, the active material will fall off, and when the amount of solid-state electrolyte added is too much, the content of the corresponding conductive agent is too low, the electronic impedance is large, and the capacity attenuation is rapid, therefore, too little or too much solid-state electrolyte will affect the performance, in order to play its role, the amount of addition should be within a reasonable range.

[0125] In summary, the present application provides a solid-state electrolyte, a solid-state battery pole piece and a preparation method and application thereof, the solid-state electrolyte has good ionic conductivity and adhesion, can be uniformly dispersed in the solid-state battery pole piece, reduces the content ratio of non-active substances in the solid-state battery pole piece, solves the problem that the solid-state battery pole piece needs to add additional non-active substances to reduce the performance of the battery, thereby can obviously improve the performance of the solid-state battery.

[0126] The above only describes specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and those skilled in the art should understand that any changes or replacements within the technical scope disclosed by the present application can be easily thought of by those skilled in the art, and all fall within the protection scope and disclosure scope of the present application.

Claims

1. A solid state electrolyte, characterized by, The solid-state electrolyte comprises a polymer, and the polymer comprises carbonate groups and catechol structures. The precursor of the polymer comprises carbonate monomers and catechol monomers. The carbonate monomers comprise ethylene carbonate and / or vinylene carbonate. The catechol monomers have the following general structure: ； wherein R1 is selected from C1-C6 hydrocarbon groups, and R2 is selected from C2-C6 hydrocarbon groups, and R2 comprises at least one carbon-carbon unsaturated bond.

2. The solid-state electrolyte of claim 1, wherein, The solid-state electrolyte further comprises a lithium salt.

3. The solid-state electrolyte of claim 2, wherein, Polymerization of the precursor of the polymer comprises carbonate monomers, catechol monomers, a lithium salt, and an initiator.

4. The solid-state electrolyte of claim 2, wherein, The molar ratio of the catechol monomers to the lithium salt is (0.8-1.8):

1.

5. The solid-state electrolyte of claim 2, wherein, The molar ratio of the catechol monomers to the carbonate monomers is (15-23):(77-85).

6. The solid-state electrolyte of claim 2, wherein, The molar ratio of the carbonate monomers to the lithium salt is (5-20):

1.

7. The solid-state electrolyte of claim 6, wherein, The molar ratio of the carbonate monomers to the lithium salt is (5-10):

1.

8. The solid-state electrolyte of claim 3, wherein, The amount of the initiator added is 1-5 wt% of the total weight of the carbonate monomers, the catechol monomers, and the lithium salt.

9. The solid-state electrolyte of claim 1, wherein, The raw material for preparing the catechol monomers comprises dopamine hydrochloride and an acyl chloride compound.

10. The solid-state electrolyte of claim 9, wherein, The acyl chloride compound comprises an unsaturated carbon-carbon bond.

11. The solid-state electrolyte of claim 9, wherein, The acyl chloride compound comprises any one or a combination of at least two of acryloyl chloride, but-3-enoyl chloride, or 4-pentenoyl chloride.

12. A solid state battery electrode sheet, characterized by, The solid-state battery electrode sheet comprises an active material layer, and the active material layer comprises an active material, a conductive agent, and the solid-state electrolyte according to any one of claims 1-11.

13. The solid-state battery electrode sheet of claim 12, wherein, In the solid-state battery electrode sheet, the content of the solid-state electrolyte is 8-10 wt%.

14. A method of producing a solid battery electrode sheet as claimed in claim 12 or 13, characterized by, The preparation method comprises the following steps: mixing a solvent and the solid-state electrolyte according to any one of claims 1-11 to obtain a solid-state electrolyte solution, adding an active material and a conductive agent to the solid-state electrolyte solution to obtain a slurry, and coating, drying, and rolling the slurry to obtain the solid-state battery electrode sheet.

15. A solid state battery, characterized by The solid-state battery comprises the solid-state battery electrode sheet according to claim 12 or 13.

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