Preparation method of in-situ solid-state battery structure

Abstract

The invention discloses a preparation method of an in-situ solid-state battery structure, which comprises the following steps: 1, mixing a polymer monomer, an initiator and an electrolyte to obtain an in-situ solid-state electrolyte precursor I, and mixing the in-situ solid-state electrolyte precursor I with an inorganic solid-state electrolyte to obtain an in-situ solid-state electrolyte precursor II; an in-situ solid electrolyte precursor II and an in-situ solid electrolyte precursor III are obtained; 2, preparing a positive plate and a negative plate; 3, coating the in-situ solid electrolyte precursor I on the surfaces of the positive plate and the negative plate, standing, curing and rolling to obtain a cured positive electrode and a cured negative electrode; 4, coating the surface of the cured positive electrode with the in-situ solid electrolyte precursor II, coating the surface of the cured negative electrode with the in-situ solid electrolyte precursor III, and standing and curing to obtain a composite positive electrode and a composite negative electrode; and 5, the composite positive electrode and the composite negative electrode are bonded and then cured. The preparation method effectively increases the contact area between the in-situ solid electrolyte and the positive and negative plates, improves the ion conduction efficiency, and is suitable for the technical field of battery preparation.

Description

Technical Field

[0001] The present invention belongs to the technical field of battery preparation, and particularly relates to a preparation method for an in-situ solid-state battery structure. Background Art

[0002] Due to the flammability of the liquid electrolyte in traditional lithium-ion batteries and the easy occurrence of thermal runaway (such as fire, explosion) during short circuits, etc. The liquid electrolyte and graphite anode cannot meet the higher energy density requirements of future electric vehicles and high-energy electronic devices, and the liquid electrolyte is prone to side reactions during long-term cycling, resulting in capacity attenuation and affecting the stability of the battery. To solve these problems, researchers have proposed replacing the traditional liquid electrolyte with a solid electrolyte.

[0003] Since the solid electrolyte has high safety and good thermal stability, is suitable for extreme temperature environments, and at the same time the solid interface reaction is relatively slow and there are fewer side reactions; among them, the polymer electrolyte forms a solid electrolyte in-situ inside the battery through chemical reactions or heat treatment and other means, realizing efficient contact between the electrolyte and the electrode material, thereby improving ionic conductivity and interface stability.

[0004] Although the in-situ solid-state battery technology is considered a potential way to solve the challenges of solid-state batteries, it still faces some problems. In the prior art, usually, the battery cell is first prepared, and then the in-situ solid-state electrolyte precursor is poured into the battery cell, and is cured by means of thermal initiation, ultraviolet light irradiation, etc. This method will cause problems such as uneven curing of the in-situ solid-state electrolyte precursor and large internal resistance of the battery; in addition, the porosity of the electrode sheet is further reduced after rolling, making it difficult for the in-situ solid-state electrolyte precursor to penetrate into the electrode sheet to form a continuous ion transport channel, affecting the battery performance, resulting in the in-situ formed solid electrolyte not being able to be in full contact with the positive and negative electrode materials, thereby forming an interface gap and reducing the ion conduction efficiency. Summary of the Invention

[0005] The object of the present invention is to overcome the above deficiencies in the prior art and provide a preparation method for an in-situ solid-state battery structure. This preparation method coats the in-situ solid-state electrolyte precursor on the surfaces of the unrolled positive and negative electrode sheets, and then increases the contact area between the in-situ solid-state electrolyte and the positive and negative electrode sheets and improves the compactness of the positive and negative electrode sheets through curing and rolling. Then, by coating the in-situ solid-state electrolyte precursor on the surfaces of the positive and negative electrode sheets again, it is beneficial to control the thickness of the in-situ solid-state electrolyte (the cured in-situ solid-state electrolyte precursor) on the surfaces of the positive and negative electrode sheets, solving the problem in the prior art that directly pouring the in-situ solid-state electrolyte precursor into the battery cell results in the in-situ solid-state electrolyte after curing not being able to be in full contact with the electrode sheet, leading to a reduction in ion conduction efficiency.

[0006] To achieve the above object, the technical solution adopted by the present invention is: a preparation method of an in-situ solid-state battery structure, characterized in that the preparation method comprises the following steps:

[0007] Step 1: Mix a polymer monomer, an initiator, and an electrolyte to obtain an in-situ solid-state electrolyte precursor I, and mix the in-situ solid-state electrolyte precursor I with two inorganic solid-state electrolytes respectively to obtain an in-situ solid-state electrolyte precursor II and an in-situ solid-state electrolyte precursor III;

[0008] Step 2: Coating a positive electrode slurry on the surface of a current collector to obtain a positive electrode sheet, and coating a negative electrode slurry on the surface of a current collector to obtain a negative electrode sheet;

[0009] Step 3: Coating the in-situ solid-state electrolyte precursor I obtained in Step 1 on the surfaces of the positive electrode sheet and the negative electrode sheet obtained in Step 2, standing and curing, and then rolling to obtain a cured positive electrode and a cured negative electrode;

[0010] Step 4: Coating the in-situ solid-state electrolyte precursor II obtained in Step 1 on the surface of the cured positive electrode obtained in Step 3, and coating the in-situ solid-state electrolyte precursor III obtained in Step 1 on the surface of the cured negative electrode obtained in Step 3, standing and curing to obtain a composite positive electrode and a composite negative electrode with a gel-like solid-state electrolyte layer;

[0011] Step 5: Bonding the composite positive electrode and the composite negative electrode obtained in Step 4, and curing to obtain an in-situ solid-state battery structure.

[0012] In the above preparation method of an in-situ solid-state battery structure, it is characterized in that the mass ratio of the inorganic solid-state electrolyte to the polymer monomer in the electrolyte precursor II and the electrolyte precursor III in Step 1 is not greater than 3:5.

[0013] In the above preparation method of an in-situ solid-state battery structure, it is characterized in that the inorganic solid-state electrolyte in the in-situ solid-state electrolyte precursor II in Step 1 is an oxidation-resistant inorganic solid-state electrolyte, and the inorganic solid-state electrolyte in the in-situ solid-state electrolyte precursor III is a reduction-resistant inorganic solid-state electrolyte.

[0014] In the above preparation method of an in-situ solid-state battery structure, it is characterized in that the oxidation-resistant inorganic solid-state electrolyte is one of LATP, LLZO, LISICON, and Li3YCl6, and the reduction-resistant inorganic solid-state electrolyte is one of LLTO, Li3PS4, and Li2ZrCl6.

[0015] In the present invention, by selecting LATP (lithium aluminum titanium phosphate), LLZO (lithium lanthanum zirconium oxide), LISICON (lithium superionic conductor), Li3YCl6 (halide solid electrolyte) with oxidation resistance and coating them on the surface of the solidified positive electrode, it has the effects of being compatible with high-voltage positive electrode materials, enhancing thermal stability and safety, broadening the electrochemical window, suppressing interfacial side reactions, and improving the long cycle life of the battery; by selecting LLTO (lithium lanthanum titanium oxide), Li3PS4 (sulfide solid electrolyte), Li2ZrCl6 (halide solid electrolyte) with reduction resistance and coating them on the surface of the solidified negative electrode, it has the effects of suppressing electrolyte decomposition, reducing interfacial impedance, enhancing the energy density of the battery, wide-temperature stability, and simplifying interfacial engineering.

[0016] The preparation method of the above-mentioned in-situ solid-state battery structure is characterized in that, in step one, the polymer monomer is one or more of ester monomers, carbonate monomers, amide monomers, nitrile monomers, fluorinated monomers, ether compounds, and oligomers containing ether segments, the initiator is one or more of azo initiators, peroxide initiators, and cationic and anionic initiators, and the electrolyte includes a solvent and a lithium salt.

[0017] The preparation method of the above-mentioned in-situ solid-state battery structure is characterized in that the solvent is one or more of ethylene carbonate, fluoroethylene carbonate, propylene carbonate, and ethylene glycol dimethyl ether.

[0018] The preparation method of the above-mentioned in-situ solid-state battery structure is characterized in that, in step three, the standing time is 8h - 24h, and the solidification method is: irradiating with ultraviolet light with a wavelength of 250nm - 400nm for 100s - 400s.

[0019] The preparation method of the above-mentioned in-situ solid-state battery structure is characterized in that, in step three, the thicknesses of the solidified positive electrode and the solidified negative electrode after rolling are reduced by not less than 50μm.

[0020] In the present invention, by controlling the rolling thickness, the contact between the components inside the in-situ solid electrolyte and between the in-situ solid electrolyte and the positive and negative electrode sheets is made closer, thereby improving the electrical performance and energy density of the battery.

[0021] The preparation method of the above-mentioned in-situ solid-state battery structure is characterized in that, in step four, the standing time is 5h - 12h, the solidification method is: irradiating with ultraviolet light with a wavelength of 250nm - 400nm for 50s - 200s, and the thickness of the gel-like solid electrolyte layer is 60μm - 200μm.

[0022] By controlling the standing time, the inorganic solid electrolytes in the in-situ solid electrolyte precursor II and the in-situ solid electrolyte precursor III can settle on the surfaces of the positive and negative electrode plates respectively, forming an asymmetric electrolyte layer on the surfaces of the positive and negative electrode plates, which helps to alleviate the side reactions between the in-situ solid electrolyte and the positive and negative electrode plates; by controlling the mass ratio of the inorganic solid electrolyte to the polymer monomer and controlling the thickness of the gel-like solid electrolyte layer to be 60 μm to 200 μm, the thickness of the inorganic solid electrolyte after settlement is 2 μm to 40 μm, avoiding the situation that the inorganic solid electrolyte is too thin or cannot completely cover the surface of the electrode plate, making it difficult to achieve the expected design performance of the battery, and avoiding the situation that the inorganic solid electrolyte is too thick, resulting in poor adhesion between the positive and negative electrode plates, causing too large a distance between the positive and negative electrodes and difficult ion transport.

[0023] The preparation method of the above-mentioned in-situ solid-state battery structure is characterized in that the curing method in step five is: standing for 80 s to 240 s in an environment with a temperature of 50 °C to 100 °C and a pressure of 30 PSI to 60 PSI.

[0024] By controlling the curing process in a heating and pressurizing environment, the present invention can make the surfaces of the composite positive electrode and the composite negative electrode fit completely, the in-situ solid electrolyte is in closer contact with the positive and negative electrode plates, and the in-situ solid electrolyte is more uniform inside and on the surfaces of the positive and negative electrode plates, effectively increasing the ion transport channels of the battery and reducing the interfacial impedance between the in-situ solid electrolyte and the positive and negative electrode plates.

[0025] The present invention has the following advantages compared with the prior art:

[0026] 1. By coating the in-situ solid electrolyte precursor on the surfaces of the unrolled positive and negative electrode plates, since there are a large number of pores in the unrolled positive and negative electrode plates, the in-situ solid electrolyte precursor can be infused into the gaps between the active material particles of the positive and negative electrode plates, increasing the contact area between the positive and negative electrode plates and the in-situ solid electrolyte precursor, which is beneficial to forming continuous ion transport channels; then, by rolling, the compactness of the positive and negative electrode plates and the in-situ solid electrolyte is improved, thereby enhancing the electrical performance and energy density of the in-situ solid-state battery.

[0027] 2. By coating the in-situ solid electrolyte precursor on the surfaces of the positive and negative electrode plates again and curing it, it is used to control the thickness of the in-situ solid electrolyte on the surfaces of the positive and negative electrode plates and to improve the thickness difference of each part on the surfaces of the positive and negative electrode plates caused by rolling, making the contact area larger after the positive and negative electrode plates are fitted; at the same time, the in-situ solid electrolyte precursor coated again contains an inorganic solid electrolyte, and during the standing process, the inorganic solid electrolyte will settle under the action of gravity, forming an asymmetric electrolyte layer on the surfaces of the positive and negative electrode plates, which helps to alleviate the side reactions between the in-situ solid electrolyte and the positive and negative electrode plates.

[0028] 3. The gel-like solid electrolyte layer formed on the surfaces of the composite positive electrode and the composite negative electrode of the present invention enables the composite positive electrode and the composite negative electrode to be closely attached. Then, curing is performed by heating and pressing to reduce the resistance of the attachment surface, and the separator between the positive and negative electrodes of the battery in the prior art can be removed, which is beneficial to improving the integrity of the in-situ solid-state battery structure.

[0029] The technical solution of the present invention will be further described in detail below with reference to the drawings and embodiments. Description of the Drawings

[0030] Figure 1 It is a schematic diagram of the in-situ solid-state battery structure of the present invention. Detailed Embodiments

[0031] Embodiment 1

[0032] The preparation method of this embodiment includes the following steps:

[0033] Step 1: By mass, 5 parts of pentaerythritol tetraacrylate, 0.05 part of azobisisobutyronitrile, and 50 parts of electrolyte are mixed to obtain in-situ solid electrolyte precursor I. 5 parts of pentaerythritol tetraacrylate, 0.05 part of azobisisobutyronitrile, 50 parts of electrolyte, and 1 part of LLZO are mixed to obtain in-situ solid electrolyte precursor II. 5 parts of pentaerythritol tetraacrylate, 0.05 part of azobisisobutyronitrile, 50 parts of electrolyte, and 1 part of LLTO are mixed to obtain in-situ solid electrolyte precursor III. The electrolyte is composed of lithium hexafluorophosphate, fluoroethylene carbonate, ethylene carbonate, and lithium difluorooxalate borate;

[0034] Step 2: By mass, 95 parts of lithium cobaltate, 2 parts of polyvinylidene fluoride, and 3 parts of carbon black are mixed evenly in N-methylpyrrolidone, coated on the surface of aluminum foil and dried to obtain a positive electrode sheet. 95 parts of graphite, 2 parts of styrene-butadiene rubber, 2 parts of carbon black, and 1 part of carbon nanotube are mixed evenly in water and N-methylpyrrolidone, coated on the surface of a copper foil current collector and dried to obtain a negative electrode sheet;

[0035] Step 3: The in-situ solid electrolyte precursor I obtained in Step 1 is coated on the surfaces of the positive electrode sheet and the negative electrode sheet. After standing for 12 h, ultraviolet light with a wavelength of 250 nm is applied to the positive and negative electrode sheets for 400 s to obtain a cured positive electrode with a thickness of 200 μm and a cured negative electrode with a thickness of 170 μm. Then, rolling is performed to obtain a cured positive electrode with a thickness of 150 μm and a cured negative electrode with a thickness of 120 μm;

[0036] Step 4: Coating the in-situ solid electrolyte precursor II obtained in Step 1 on the surface of the cured positive electrode obtained in Step 3, and coating the in-situ solid electrolyte precursor III obtained in Step 1 on the surface of the cured negative electrode obtained in Step 3. Let it stand at 40 °C for 5 h, and then irradiate the cured positive electrode and the cured negative electrode with ultraviolet light with a wavelength of 250 nm for 200 s to obtain a composite positive electrode and a composite negative electrode with a gel-like solid electrolyte layer. The thicknesses of the gel-like solid electrolyte layers are 60 μm and 70 μm respectively, and the thicknesses of the inorganic solid electrolytes are both 13 μm;

[0037] Step 5: Completely fitting the composite positive electrode and the composite negative electrode obtained in Step 4, and curing them at a temperature of 100 °C under a pressure of 30 PSI for 80 s to obtain the Figure 1 in-situ solid-state battery structure as shown, and assembling it into a solid-state battery after cutting.

[0038] In this embodiment, the pentaerythritol tetraacrylate in Step 1 can also be replaced by one or more of ester monomers, carbonate monomers, amide monomers, nitrile monomers, fluorinated monomers, ether compounds, and oligomers containing ether linkages other than pentaerythritol tetraacrylate. The azobisisobutyronitrile can also be replaced by one or more of azo initiators, peroxide initiators, and cationic and anionic initiators other than azobisisobutyronitrile. The LLZO can also be replaced by LISICON or Li3YCl6, the LLTO can be replaced by Li3PS4, the fluoroethylene carbonate and ethylene carbonate can be replaced by ethylene carbonate and / or ethylene glycol dimethyl ether, and the lithium hexafluorophosphate and lithium difluoro(oxalato)borate can be replaced by one or more of lithium bis(fluorosulfonyl)imide, lithium tetrafluoroborate, and lithium bis(trifluoromethylsulfonyl)imide.

[0039] After 100 cycles, the interfacial impedance of the solid-state battery prepared in this embodiment is not greater than 100 ohm, and the capacity retention rate is not less than 90%.

[0040] Example 2

[0041] The preparation method of this embodiment includes the following steps:

[0042] Step 1: Taking parts by mass, mixing 5 parts of pentaerythritol tetraacrylate, 0.05 part of azobisisobutyronitrile and 50 parts of electrolyte solution to obtain the in-situ solid electrolyte precursor I. Mixing 5 parts of pentaerythritol tetraacrylate, 0.05 part of azobisisobutyronitrile, 50 parts of electrolyte solution and 2 parts of LLZO to obtain the in-situ solid electrolyte precursor II. Mixing 5 parts of pentaerythritol tetraacrylate, 0.05 part of azobisisobutyronitrile, 50 parts of electrolyte and 2 parts of Li2ZrCl6 to obtain the in-situ solid electrolyte precursor III. The electrolyte solutions are all composed of lithium hexafluorophosphate, fluoroethylene carbonate, ethylene carbonate, and lithium difluoro(oxalato)borate;

[0043] Step 2: By mass fraction, mix 95 parts of lithium cobaltate, 2 parts of polyvinylidene fluoride, and 3 parts of carbon black evenly in N-methylpyrrolidone, coat the mixture on the surface of aluminum foil, and dry it to obtain a positive electrode sheet; mix 95 parts of silicon carbon, 2 parts of styrene-butadiene rubber, 2 parts of carbon black, and 1 part of carbon nanotube evenly in water and N-methylpyrrolidone, coat the mixture on the surface of a copper foil current collector, and dry it to obtain a negative electrode sheet;

[0044] Step 3: Coat the in-situ solid electrolyte precursor Ⅰ obtained in Step 1 on the surfaces of the positive electrode sheet and the negative electrode sheet. After standing for 10 h, irradiate the positive and negative electrode sheets with ultraviolet light having a wavelength of 280 nm for 300 s to obtain a solidified positive electrode with a thickness of 210 μm and a solidified negative electrode with a thickness of 160 μm. Then, perform rolling to obtain a solidified positive electrode with a thickness of 150 μm and a solidified negative electrode with a thickness of 90 μm;

[0045] Step 4: Coat the in-situ solid electrolyte precursor Ⅱ obtained in Step 1 on the surface of the solidified positive electrode obtained in Step 3, and coat the in-situ solid electrolyte precursor Ⅲ obtained in Step 1 on the surface of the solidified negative electrode obtained in Step 3. Let it stand at 28 °C for 10 h, and then irradiate the solidified positive electrode and the solidified negative electrode with ultraviolet light having a wavelength of 280 nm for 150 s to obtain a composite positive electrode and a composite negative electrode with gel-like solid electrolyte layers. The thicknesses of the gel-like solid electrolyte layers are 80 μm and 90 μm respectively, and the thickness of the inorganic solid electrolyte is 26 μm for both;

[0046] Step 5: Completely bond the composite positive electrode and the composite negative electrode obtained in Step 4, and cure them at 80 °C under a pressure of 40 PSI for 150 s to obtain an in-situ solid battery structure. After cutting, assemble it into a solid battery.

[0047] After 100 cycles, the interfacial impedance of the solid battery prepared in this example is not greater than 100 ohm, and the capacity retention rate is not less than 90%.

[0048] Example 3

[0049] The preparation method of this example includes the following steps:

[0050] Step 1: By mass fraction, mix 5 parts of maleic anhydride, 0.05 part of azobisisobutyronitrile, and 100 parts of electrolyte to obtain an in-situ solid electrolyte precursor Ⅰ, mix 5 parts of maleic anhydride, 0.05 part of azobisisobutyronitrile, 100 parts of electrolyte, and 2.5 parts of LATP to obtain an in-situ solid electrolyte precursor Ⅱ, and mix 5 parts of maleic anhydride, 0.05 part of azobisisobutyronitrile, 100 parts of electrolyte, and 2.5 parts of LLTO to obtain an in-situ solid electrolyte precursor Ⅲ; the electrolyte is composed of lithium hexafluorophosphate, fluoroethylene carbonate, ethylene carbonate, and lithium difluorooxalate borate;

[0051] Step 2: Taking parts by mass, mix 95 parts of lithium iron phosphate, 2 parts of polyvinylidene fluoride, and 3 parts of carbon nanotubes evenly in N-methylpyrrolidone, coat the mixture on the surface of aluminum foil and dry it to obtain a positive electrode sheet; mix 95 parts of graphite, 2 parts of styrene-butadiene rubber, 2 parts of carbon black, and 1 part of carbon nanotubes evenly in water and N-methylpyrrolidone, coat the mixture on the surface of copper foil and dry it to obtain a negative electrode sheet;

[0052] Step 3: Coat the in-situ solid electrolyte precursor Ⅰ obtained in Step 1 on the surfaces of the positive electrode sheet and the negative electrode sheet. After standing for 8 h, irradiate the positive and negative electrode sheets with ultraviolet light with a wavelength of 300 nm for 200 s to obtain a solidified positive electrode with a thickness of 215 μm and a solidified negative electrode with a thickness of 150 μm. Then perform rolling to obtain a solidified positive electrode with a thickness of 160 μm and a solidified negative electrode with a thickness of 80 μm;

[0053] Step 4: Coat the in-situ solid electrolyte precursor Ⅱ obtained in Step 1 on the surface of the solidified positive electrode obtained in Step 3, coat the in-situ solid electrolyte precursor Ⅲ obtained in Step 1 on the surface of the solidified negative electrode obtained in Step 3, stand at 30 °C for 7 h, and then irradiate the solidified positive electrode and the solidified negative electrode with ultraviolet light with a wavelength of 300 nm for 100 s to obtain a composite positive electrode and a composite negative electrode with gel-like solid electrolyte layers. The thicknesses of the gel-like solid electrolyte layers are 120 μm and 80 μm respectively, and the thickness of the inorganic solid electrolyte is 33 μm;

[0054] Step 5: Completely bond the composite positive electrode and the composite negative electrode obtained in Step 4, and cure them at a temperature of 60 °C under a pressure of 50 PSI for 200 s to obtain an in-situ solid battery structure. After cutting, assemble it into a battery.

[0055] After 100 cycles, the interfacial impedance of the solid battery prepared in this example is not greater than 100 ohm, and the capacity retention rate is not less than 90%.

[0056] Example 4

[0057] The preparation method of this example includes the following steps:

[0058] Step 1: Taking parts by mass, mix 5 parts of maleic anhydride, 0.05 part of azobisisobutyronitrile, and 100 parts of electrolyte solution to obtain an in-situ solid electrolyte precursor Ⅰ; mix 5 parts of maleic anhydride, 0.05 part of azobisisobutyronitrile, 100 parts of electrolyte, and 3 parts of LATP to obtain an in-situ solid electrolyte precursor Ⅱ; mix 5 parts of maleic anhydride, 0.05 part of azobisisobutyronitrile, 100 parts of electrolyte, and 3 parts of Li2ZrCl6 to obtain an in-situ solid electrolyte precursor Ⅲ; the electrolyte solutions are all composed of lithium hexafluorophosphate, fluoroethylene carbonate, ethylene carbonate, and lithium difluorooxalate borate;

[0059] Step 2: By mass fraction, 95 parts of lithium iron phosphate, 2 parts of polyvinylidene fluoride, and 3 parts of carbon nanotubes are mixed evenly in N-methylpyrrolidone, coated on the surface of aluminum foil and dried to obtain a positive electrode sheet; 95 parts of silicon carbide, 2 parts of styrene-butadiene rubber, 2 parts of carbon black, and 1 part of carbon nanotubes are mixed evenly in water and N-methylpyrrolidone, coated on the surface of copper foil and dried to obtain a negative electrode sheet;

[0060] Step 3: The in-situ solid electrolyte precursor I obtained in Step 1 is coated on the surfaces of the positive and negative electrode sheets. After standing for 24 h, ultraviolet light with a wavelength of 400 nm is applied to the positive and negative electrode sheets for 100 s to obtain a cured positive electrode with a thickness of 220 μm and a cured negative electrode with a thickness of 170 μm. Then, rolling is performed to obtain a cured positive electrode with a thickness of 120 μm and a cured negative electrode with a thickness of 70 μm;

[0061] Step 4: The in-situ solid electrolyte precursor II obtained in Step 1 is coated on the surface of the cured positive electrode obtained in Step 3, and the in-situ solid electrolyte precursor III obtained in Step 1 is coated on the surface of the cured negative electrode obtained in Step 3. After standing at 25 °C for 12 h, ultraviolet light with a wavelength of 400 nm is applied to the cured positive and negative electrodes for 50 s to obtain a composite positive electrode and a composite negative electrode with gel-like solid electrolyte layers. The thicknesses of the gel-like solid electrolyte layers are 200 μm and 100 μm, respectively, and the thickness of the inorganic solid electrolyte is 40 μm;

[0062] Step 5: The composite positive electrode and the composite negative electrode obtained in Step 4 are completely adhered, and cured at 50 °C under a pressure of 60 PSI for 240 s to obtain an in-situ solid battery structure, which is cut and assembled into a battery.

[0063] After 100 cycles, the interfacial impedance of the solid battery prepared in this example is not greater than 100 ohm, and the capacity retention rate is not less than 90%.

[0064] The above is only a preferred embodiment of the present invention, and does not impose any limitations on the present invention. Any simple modifications, changes, and equivalent structural transformations made to the above embodiments according to the technical essence of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A preparation method of an in-situ solid-state battery structure, characterized in that, The preparation method includes the following steps: Step 1: Mix the polymer monomer, initiator, and electrolyte to obtain the in-situ solid electrolyte precursor I. Then mix the in-situ solid electrolyte precursor I with two inorganic solid electrolytes respectively to obtain the in-situ solid electrolyte precursor II and the in-situ solid electrolyte precursor III; Step 2: Coating the positive electrode paste on the surface of the current collector to obtain the positive electrode sheet, and coating the negative electrode paste on the surface of the current collector to obtain the negative electrode sheet; Step 3: Coating the in-situ solid electrolyte precursor I obtained in Step 1 on the surfaces of the positive electrode sheet and the negative electrode sheet obtained in Step 2. After standing and curing, roll pressing is carried out to obtain the cured positive electrode and the cured negative electrode; Step 4: Coating the in-situ solid electrolyte precursor II obtained in Step 1 on the surface of the cured positive electrode obtained in Step 3, and coating the in-situ solid electrolyte precursor III obtained in Step 1 on the surface of the cured negative electrode obtained in Step 3. After standing and curing, a composite positive electrode and a composite negative electrode with a gel-like solid electrolyte layer are obtained; Step 5: Bond the composite positive electrode and the composite negative electrode obtained in Step 4, and after curing, an in-situ solid battery structure is obtained.

2. The preparation method of an in-situ solid-state battery structure according to claim 1, characterized in that, In Step 1, the mass ratio of the inorganic solid electrolyte to the polymer monomer in the electrolyte precursor II and the electrolyte precursor III is not greater than 3:

5.

3. The preparation method of an in-situ solid-state battery structure according to claim 1, characterized in that, In Step 1, the inorganic solid electrolyte in the in-situ solid electrolyte precursor II is an oxidation-resistant inorganic solid electrolyte, and the inorganic solid electrolyte in the in-situ solid electrolyte precursor III is a reduction-resistant inorganic solid electrolyte.

4. The preparation method of an in-situ solid-state battery structure according to claim 3, characterized in that, The oxidation-resistant inorganic solid electrolyte is one of LATP, LLZO, LISICON, Li3YCl6, and the reduction-resistant inorganic solid electrolyte is one of LLTO, Li3PS4, Li2ZrCl6.

5. The preparation method of an in-situ solid-state battery structure according to claim 1, characterized in that, In Step 1, the polymer monomer is one or more of ester monomers, carbonate monomers, amide monomers, nitrile monomers, fluorinated monomers, ether compounds, and oligomers containing ether segments. The initiator is one or more of azo initiators, peroxide initiators, and cationic and anionic initiators. The electrolyte includes a solvent and a lithium salt.

6. The preparation method of an in-situ solid-state battery structure according to claim 5, characterized in that The solvent is one or more of ethylene carbonate, fluoroethylene carbonate, propylene carbonate, and ethylene glycol dimethyl ether.

7. The preparation method of an in-situ solid-state battery structure according to claim 1, characterized in that, In Step 3, the standing time is 8h - 24h, and the curing method is: irradiating with ultraviolet light with a wavelength of 250nm - 400nm for 100s - 400s.

8. The preparation method of an in-situ solid-state battery structure according to claim 1, characterized in that, After roll pressing in Step 3, the thickness of both the cured positive electrode and the cured negative electrode is reduced by not less than 50μm.

9. The preparation method of an in-situ solid-state battery structure according to claim 1, characterized in that In Step 4, the standing time is 5h - 12h, and the curing method is: irradiating with ultraviolet light with a wavelength of 250nm - 400nm for 50s - 200s. The thickness of the gel-like solid electrolyte layer is 60μm - 200μm.

10. The preparation method of a solid-state battery structure in situ according to claim 1, characterized in that, In Step 5, the curing method is: standing for 80s - 240s in an environment with a temperature of 50°C - 100°C and a pressure of 30PSI - 60PSI.

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