A 4D printing gel solid electrolyte, printing method and solid battery

Abstract

This invention relates to the field of solid-state electrolyte battery technology, specifically to a 4D-printed gel solid-state electrolyte, a printing method, and a solid-state battery. This application utilizes 3D printing technology to pre-construct a solid-state electrolyte composed of an insoluble polymer framework and a soluble polymer functional phase. When a trace amount of electrolyte is introduced, this structure undergoes a predetermined, controllable evolution over time—the soluble components rapidly dissolve and gel in situ, dynamically coating the surface and pores of the insoluble framework, thereby forming a gel electrolyte that combines a stable three-dimensional framework with a high ionic conductivity gel interface layer. This achieves a 4D-printed gel solid-state electrolyte. This 4D-printed gel solid-state electrolyte effectively buffers volume changes and significantly reduces interfacial impedance. Simultaneously, its insoluble framework ensures mechanical strength and dimensional stability, while the extremely low electrolyte usage fundamentally improves battery safety and cycle performance.

Description

Technical Field

[0001] This invention relates to the field of solid electrolyte battery technology, specifically to a 4D printed gel solid electrolyte, a printing method, and a solid battery. Background Technology

[0002] With the global energy structure transformation, high-energy-density and high-safety energy storage devices have become a core direction for scientific research and industrial development. While secondary batteries such as lithium-ion batteries are widely used, traditional liquid electrolytes have inherent defects such as easy leakage, flammability, explosiveness, and poor thermal stability, raising serious safety concerns and limiting further improvements in battery energy density. Solid-state batteries are considered an ideal solution for next-generation energy storage technology. By using solid electrolytes instead of liquid electrolytes, they are expected to fundamentally solve safety issues and may achieve compatibility with high-capacity metal anodes (such as lithium metal anodes), thereby significantly improving battery energy density. Among numerous solid-state electrolyte materials, hydrogel / microgel electrolytes have attracted widespread attention due to their three-dimensional polymer network structure, which can effectively accommodate electrolytes, and their advantages such as high ionic conductivity and good contact with the electrode interface.

[0003] However, existing gel electrolytes, especially pre-polymerized solid gel electrolytes, still face two major technical bottlenecks when applied to practical applications: First, there is a static contradiction between structure and performance. Gel electrolytes prepared using traditional methods (such as solution casting and UV curing) have their microstructure (such as pore size and crosslinking density) and macroscopic morphology fixed after preparation. This "static" characteristic cannot adapt to the drastic changes in electrode volume during battery cycling, leading to interfacial contact failure, stress accumulation, and consequently, high interfacial impedance, even causing battery failure. This problem is particularly prominent for systems with significant volume changes, such as silicon anodes and lithium metal anodes. Second, manufacturing complex configurations is difficult. Traditional manufacturing processes cannot easily produce integrated solid-state batteries with complex three-dimensional structures or multi-material integration in a single step. This limits the ability to optimize ion transport paths and achieve higher areal capacity and power density in battery designs within a limited space.

[0004] Therefore, there is an urgent need in this field to improve the structure and preparation process of existing solid electrolytes in order to improve the overall performance of solid batteries, reduce the occurrence of battery failures, and improve battery cycle performance and energy storage performance to a certain extent. Summary of the Invention

[0005] One of the objectives of this invention is to provide a 4D-printed gel solid electrolyte that overcomes the technical bottlenecks of existing solid electrolytes, such as high interfacial impedance, difficulty in adapting to changes in electrode volume, and significant safety hazards associated with traditional liquid injection methods.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A 4D-printed gel solid electrolyte is formed by adding electrolyte dropwise to a solid electrolyte after it has been printed by a 3D printer. Solid electrolytes include: Soluble polymers include at least one of the following: polymers containing carbonate groups, polymers containing ether bonds, and polymers containing ester groups; Photoinitiator; Insoluble polymers include at least one of polyolefins, fluoropolymers, engineering plastics and high-performance polymers, highly cross-linked polymer networks, or inorganic-organic hybrid polymers.

[0007] The above technical solution produces the following technical effects: This application pre-constructs a solid electrolyte composed of an insoluble polymer skeleton and a soluble polymer functional phase using the aforementioned 3D printing technology. When a trace amount of electrolyte is introduced, the structure undergoes a predetermined and controllable evolution over time—the soluble component rapidly dissolves and gels in situ, dynamically coating the surface and pores of the insoluble skeleton, thereby forming a gel electrolyte that combines a stable three-dimensional skeleton with a gel interface layer with high ionic conductivity, thus realizing 4D printing of a gel solid electrolyte.

[0008] This gel solid electrolyte not only achieves a tight, flexible, and adaptive contact between the electrolyte and the electrode, effectively buffering volume changes and significantly reducing interfacial impedance, but its insoluble framework also ensures mechanical strength and dimensional stability, while the extremely low electrolyte usage fundamentally improves battery safety.

[0009] As a further improvement to the 4D printing gel solid electrolyte of this application, the carbonate-based polymer includes at least one of polyethylene carbonate, polypropylene carbonate, and aliphatic polycarbonate.

[0010] As a further improvement to the 4D printing gel solid electrolyte of this application, the ether-containing polymer includes at least one of polyethylene oxide, polyethylene glycol or polypropylene oxide with a molecular weight of 1000 g / mol to 1000000 g / mol.

[0011] As a further improvement to the 4D printing gel solid electrolyte of this application, the ester-containing polymer includes at least one of polymethyl methacrylate, polycaprolactone, and polyvinyl acetate.

[0012] As a further improvement to the 4D printing gel solid electrolyte of this application, the photoinitiator is 2-hydroxy-2-methyl-1-phenyl-1-propanone, which initiates a cross-linking reaction of insoluble polymers under ultraviolet irradiation to form a three-dimensional network skeleton.

[0013] As a further improvement to the 4D printing gel solid electrolyte of this application, the polyolefin includes at least one of polyethylene and polypropylene.

[0014] As a further improvement to the 4D printing gel solid electrolyte of this application, the fluoropolymer includes at least one of polytetrafluoroethylene and perfluorosulfonic acid resin.

[0015] As a further improvement to the 4D printing gel solid electrolyte of this application, the engineering plastic and high-performance polymer include at least one of polyimide, polybenzimidazole, and polyetheretherketone.

[0016] As a further improvement to the 4D printing gel solid electrolyte of this application, a highly cross-linked polymer network includes at least one of cross-linked polyacrylate, cross-linked epoxy resin, phenolic resin, and urea-formaldehyde resin.

[0017] As a further improvement to the 4D printing gel solid electrolyte of this application, the inorganic-organic hybrid composite polymer includes at least one of polysiloxane alkyl composite materials and ceramic nanoparticle composite polymers.

[0018] The second objective of this invention is to provide a 4D printing method for gel solid electrolytes, which further solves the problems of complex preparation processes, high costs, and unstable performance of prepared solid electrolytes.

[0019] To achieve the above-mentioned objectives, this application implements the following technical solution: A 4D printing method for gel solid electrolytes includes the following steps: Step S1: Dissolve the insoluble polymer in the first solvent and stir to form a viscous solution. Prepare photocurable printing ink A by mixing the viscous solution with a photoinitiator and print the insoluble skeleton using a 3D printer. Step S2: Dissolve the soluble polymer in the second solvent and stir to form printing ink B. Printing ink B is then used to alternately print with the insoluble skeleton using a 3D printer to form a solid electrolyte membrane. Step S3: Dry the solid electrolyte membrane, and then uniformly drop electrolyte onto the surface of the solid electrolyte membrane to obtain 4D printed gel solid electrolyte.

[0020] The above technical solution produces the following technical effects: After the solid electrolyte framework is printed in steps S1 and S2, the framework is solidified and insoluble, while the soluble polymer is dispersed or attached to the surface or internal pores of the framework. Adding a trace amount of electrolyte triggers the dissolution-gelation of the latter, realizing the design concept of a 4D gel solid electrolyte. By changing the amount of electrolyte added and the total number of printing layers of insoluble framework polymer precursor and soluble gel polymer precursor, the cycle performance of the battery based on the 4D printed gel solid electrolyte can be controlled.

[0021] As a further improvement to the 4D printing gel solid electrolyte printing method of this application, in step S1, the insoluble polymer accounts for 50wt%-60wt% of the mass ratio of printing ink A; the first solvent is N-methylpyrrolidone, and the first solvent accounts for 30wt%-40wt% of the mass ratio of printing ink A.

[0022] As a further improvement to the 4D printing gel solid electrolyte printing method of this application, the insoluble polymer and the first solvent are magnetically stirred in a 60°C water bath for 6 hours to form a viscous solution.

[0023] As a further improvement to the 4D printing gel solid electrolyte printing method of this application, the amount of photoinitiator added to the viscous solution is 1wt%-5wt% of the total mass of printing ink A. After adding the photoinitiator to the viscous solution, it is stirred for 10-30 minutes under dark conditions to obtain photocured printing ink A.

[0024] As a further improvement to the 4D printing gel solid electrolyte printing method of this application, the second solvent is N,N-dimethylformamide, and the second solvent accounts for 20wt%-40wt% of the mass ratio of printing ink B; the soluble polymer accounts for 60wt%-80wt% of the mass ratio of printing ink B. The second solvent and the soluble polymer are magnetically stirred in a 60°C water bath for 6 hours to form printing ink B.

[0025] As a further improvement to the 4D printing gel solid electrolyte printing method of this application, the 3D printer is a pneumatic direct-write 3D printer. The 3D printer adds the prepared printing ink A and printing ink B into the 3D printer barrel respectively, and prints at room temperature through a conical nozzle with an inner diameter of 0.4mm. The 3D printer uses a grid-like printing path with a filament pitch of 300 μm and a moving speed of 30-150 mm / s.

[0026] As a further improvement to the 4D printing gel solid electrolyte printing method of this application, in step S1, when the 3D printer prints the insoluble skeleton, a 365 nm ultraviolet LED light source is used for simultaneous in-situ curing, and the light intensity of the ultraviolet LED light source is 30 mW / cm². 2 ; Insoluble polymers are cross-linked using ultraviolet LED light sources to form an insoluble three-dimensional network framework.

[0027] As a further improvement to the 4D printing gel solid electrolyte printing method of this application, the solid electrolyte membrane obtained in step S3 is placed in a vacuum drying oven at 60°C for 24 hours.

[0028] As a further improvement to the 4D printing gel solid electrolyte printing method of this application, the dried solid electrolyte membrane is transferred to a glove box filled with argon gas, and electrolyte is uniformly added to the surface of the solid electrolyte membrane using a micro-drop method. The amount of electrolyte added is 2%-5% of the total mass of the insoluble polymer and the soluble polymer.

[0029] The third objective of this invention is to provide a solid-state battery comprising the above-mentioned 4D-printed gel solid electrolyte, thereby further improving the overall performance of solid-state batteries.

[0030] In order to achieve the above-mentioned objectives of the invention, A solid-state battery comprising any of the above-mentioned 4D-printed gel solid electrolyte, positive electrode, and negative electrode, wherein the positive electrode active material in the positive electrode comprises layered oxide, lithium iron phosphate, and Prussian blue analogues or polyanionic compounds. The negative electrode active material in the negative electrode sheet includes lithium metal, lithium titanate, hard carbon or soft carbon, and silicon-based materials.

[0031] The above technical solution produces the following technical effects: The solid-state battery described in this application, employing the aforementioned 4D-printed gel solid electrolyte, exhibits excellent ion conductivity. This gel solid electrolyte's unique insoluble three-dimensional network framework structure provides a stable and efficient channel for lithium-ion transport, significantly increasing the rate of ion migration within the battery. This allows for faster ion exchange during charging and discharging, thereby significantly improving the battery's charging and discharging efficiency. Attached Figure Description

[0032] Figure 1 This is a diagram illustrating the printing process of the 4D printing gel solid electrolyte method of the present invention. Figure 2 This is a flowchart of the 4D printing gel solid electrolyte printing method of the present invention. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention. To facilitate an accurate understanding of the solutions provided by the following embodiments, the terms involved in this invention are explained as follows before describing the technical solutions provided by this invention: Lithium / Sodium-ion Battery (LIB / SIB): A type of rechargeable battery that stores and releases energy through the insertion and extraction of lithium or sodium ions between the positive and negative electrodes. It features high energy density, is recyclable, and is widely used in energy storage and power battery fields.

[0035] Solid-state electrolyte (SSE): An electrolyte that combines a solid structure with gel properties, typically composed of a polymer network and an electrolyte. It replaces traditional liquid electrolytes, improving battery safety while maintaining high ionic conductivity.

[0036] 4D printing adds a time dimension to 3D printing, enabling the printed structure to undergo predetermined deformation or performance evolution under external stimuli (such as electric fields, temperature, and solvent environments), providing a revolutionary approach to solving the aforementioned problems. However, research on applying 4D printing technology to the field of solid electrolytes is still in its early stages, lacking dedicated material systems that combine excellent printability, electrochemical performance, and intelligent response capabilities. This invention aims to prepare a gel solid electrolyte with dynamic response capabilities through 4D printing.

[0037] Insoluble skeleton polymers: Polymer materials that do not dissolve in the electrolyte, serving as the three-dimensional support structure of the electrolyte. They improve mechanical strength and dimensional stability, ensuring the electrolyte structure does not collapse during cycling. Examples include polyolefins (polyethylene, polypropylene), fluoropolymers (PTFE), and highly cross-linked polymers (cross-linked polyacrylates).

[0038] Soluble polymers are polymeric materials that can dissolve in electrolytes and gel. They dissolve and gel under electrolyte triggering, forming ion transport channels and enabling adaptive contact between the electrolyte and the electrode. Examples include polypropylene carbonate (PPC), low molecular weight polyethylene oxide (PEO), and polymethyl methacrylate (PMMA).

[0039] Liquid Electrolyte: A liquid ionic conductor composed of solvent, lithium salt, and additives, used to trigger the gelation reaction of soluble polymers. In this invention, only a trace amount (2%-8% of the total polymer mass) is required to achieve dynamic transformation of 4D printed structures.

[0040] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0041] Specifically, this application recognizes an urgent need in the field to develop a novel, 4D-printable gel solid electrolyte material. This material should not only possess high ionic conductivity and good electrochemical stability, but more importantly, its printed structure should be able to undergo controllable, adaptive deformation or performance adjustment under the stimulation of external electrochemical or physical fields. This dynamically maintains close contact with the electrodes, releases internal stress, and ultimately promotes the practical application of high-safety, high-performance solid-state batteries.

[0042] Specifically, this application designs a 4D-printed gel solid electrolyte, which is formed by adding electrolyte dropwise after the solid electrolyte is printed by a 3D printer. Solid electrolytes include: soluble polymers, including at least one of polymers containing carbonate groups, polymers containing ether bonds, and polymers containing ester groups; Photoinitiator; Insoluble polymers include at least one of polyolefins, fluoropolymers, engineering plastics and high-performance polymers, highly cross-linked polymer networks, or inorganic-organic hybrid polymers.

[0043] Specifically, carbonate-based polymers include at least one of polyethylene carbonate, polypropylene carbonate, and aliphatic polycarbonate. Ether-containing polymers include at least one of polyethylene oxide, polyethylene glycol, or polypropylene oxide with a molecular weight of 1000 g / mol to 1000000 g / mol. Ester-containing polymers include at least one of polymethyl methacrylate, polycaprolactone, and polyvinyl acetate.

[0044] The photoinitiator is 2-hydroxy-2-methyl-1-phenyl-1-propanone, which initiates a cross-linking reaction of the insoluble polymer under ultraviolet irradiation to form a three-dimensional network skeleton.

[0045] Specifically, polyolefins include at least one of polyethylene and polypropylene. Fluoropolymers include at least one of polytetrafluoroethylene and perfluorosulfonic acid resins. Engineering plastics and high-performance polymers include at least one of polyimide, polybenzimidazole, and polyetheretherketone. Highly cross-linked polymer networks include at least one of cross-linked polyacrylates, cross-linked epoxy resins, phenolic resins, and urea-formaldehyde resins. Inorganic-organic hybrid composite polymers include at least one of polysiloxane alkyl composites and ceramic nanoparticle composite polymers.

[0046] In the specific implementation process, such as Figure 1-2 The 4D printing gel solid electrolyte printing method shown includes the following steps: Step S1: Dissolve the insoluble polymer in a first solvent and stir to form a viscous solution. Prepare photocurable printing ink A by combining the viscous solution with a photoinitiator, and print the insoluble skeleton using a 3D printer. The insoluble polymer accounts for 50wt%-60wt% of the mass of printing ink A. The first solvent is N-methylpyrrolidone, accounting for 30wt%-40wt% of the mass of printing ink A. The insoluble polymer and the first solvent are magnetically stirred in a 60°C water bath for 6 hours to form a viscous solution.

[0047] Furthermore, the amount of photoinitiator added to the viscous solution is 1wt%-5wt% of the total mass of printing ink A. After adding the photoinitiator to the viscous solution, it is stirred for 10-30 minutes under dark conditions to obtain photocured printing ink A. When printing the insoluble skeleton, a 365 nm ultraviolet LED light source is used for simultaneous in-situ curing, with a light intensity of 30 mW / cm². 2 ; Insoluble polymers are cross-linked using ultraviolet LED light sources to form an insoluble three-dimensional network framework.

[0048] Step S2: Dissolve the soluble polymer in a second solvent and stir to form printing ink B. Printing ink B is then used in a 3D printer to alternately print with an insoluble skeleton to form a solid electrolyte membrane. The second solvent is N,N-dimethylformamide, which accounts for 20wt%-40wt% of the mass of printing ink B. The soluble polymer accounts for 60wt%-80wt% of the mass of printing ink B. The second solvent and the soluble polymer are magnetically stirred in a 60°C water bath for 6 hours to form printing ink B.

[0049] Specifically, the 3D printer is a pneumatic direct-write 3D printer. The 3D printer adds the prepared printing ink A and printing ink B into the 3D printer barrel respectively, and prints at room temperature through a conical nozzle with an inner diameter of 0.4mm.

[0050] Furthermore, the 3D printer uses a grid-like printing path with a filament pitch of 300 μm and a moving speed of 30-150 mm / s. Printing ink A and printing ink B are used alternately for each layer.

[0051] Specifically, the number of printing layers can be adjusted. Generally, the stacking structure of printing ink A and printing ink B is ABABAB, ABABABABA, or ABA, which corresponds to 6, 9, or 3 layers. This is because different numbers of printing layers significantly affect the performance of the solid electrolyte membrane. A 6-layer ABABAB stacking structure ensures a certain level of mechanical strength while allowing for a relatively uniform distribution of ion conduction channels, facilitating rapid ion transport and thus improving the ion conductivity of the solid electrolyte. This is suitable for applications requiring fast battery charging and discharging speeds. A 9-layer ABABABABA stacking structure further increases the membrane thickness and structural complexity, better ensuring the stability and safety of the solid electrolyte membrane and effectively suppressing lithium dendrite growth. This is suitable for large-scale energy storage devices with high battery safety requirements. The 3-layer ABA stacking structure is relatively simple, with a more convenient preparation process and lower cost. By adjusting the number of printing layers, other performance parameters of the solid electrolyte membrane, such as flexibility and porosity, can be optimized according to specific application needs to meet the diverse requirements of different types of solid-state batteries.

[0052] Step S3: The solid electrolyte membrane is dried. After drying, electrolyte is uniformly added to the surface of the solid electrolyte membrane to obtain a 4D-printed gel solid electrolyte. The obtained solid electrolyte membrane is placed in a vacuum drying oven at 60°C for 24 hours. The dried solid electrolyte membrane is then transferred to an argon-filled glove box, and electrolyte is uniformly added to the surface of the solid electrolyte membrane using a micro-droplet method. The amount of electrolyte added is 2%-5% of the total mass of the insoluble and soluble polymers. After standing for 30 minutes, the electrolyte membrane undergoes the preset "4D" transformation: the soluble PPC component selectively dissolves and gels under the trigger of the micro-electrolyte, forming a gel phase in situ, which fully encapsulates and wets the insoluble polymer crosslinked framework, ultimately obtaining an adaptive microgel solid electrolyte that combines rigid support and flexible ion transport channels.

[0053] The aforementioned printing method enables the fabrication of corresponding 4D-printed gel solid electrolytes. These gel electrolytes exhibit excellent ion conductivity, providing efficient ion transport channels for solid-state batteries and thus improving charge and discharge efficiency. Simultaneously, they possess outstanding mechanical stability, effectively resisting external impacts and deformations during battery use, ensuring the integrity and stability of the battery structure.

[0054] Furthermore, to verify the technical effects of the above-mentioned technical solutions, this application prepared multiple sets of solid-state batteries as experimental test subjects based on the above-mentioned preparation method and solid-state electrolyte materials. Specifically, in another embodiment, the solid-state battery includes any of the above-mentioned 4D-printed gel solid electrolyte, positive electrode, and negative electrode. The positive electrode active material of the positive electrode is a layered oxide (such as ternary NCM / NCA) and high-safety lithium iron phosphate (LFP), as well as Prussian blue analogs or polyanionic compounds, etc. The negative electrode active material in the negative electrode includes lithium metal, lithium titanate, hard carbon or soft carbon, silicon-based materials, etc. The battery electrolyte is a common commercial electrolyte, mainly composed of non-aqueous organic solvents (including cyclic carbonates and linear carbonates), lithium salts, and common additives, which will not be described in detail here.

[0055] Step 1, Preparation of printing ink: Dissolve an insoluble backbone polymer precursor, such as polyethylene glycol diacrylate (PEGDA, molecular weight 400, crosslinking agent, 60 wt% of printing ink by mass), in N-methylpyrrolidone (NMP, solvent, 40 wt% of printing ink by mass), and magnetically stir for 6 hours in a 60°C water bath to form a homogeneous, transparent, viscous solution.

[0056] Subsequently, a photoinitiator, 2-hydroxy-2-methyl-1-phenyl-1-propanone, was added to the above solution at an amount of 1.5 wt% of the total solid mass. The mixture was stirred for 0.5 hours under light-protected conditions to obtain the final photocurable 3D printing ink, designated as ink A.

[0057] A soluble gel polymer precursor, such as polypropylene carbonate (PPC, Mn=50,000, 80 wt% of the printing ink), was dissolved in N,N-dimethylformamide (DMF, solvent, 20 wt% of the printing ink) and magnetically stirred in a 60°C water bath for 6 hours to form a homogeneous, transparent, viscous solution. This ink is designated as B.

[0058] Step 2, 3D Printing: Load the prepared ink into the cartridge of the pneumatic direct-write 3D printer. Select a conical nozzle with an inner diameter of 0.4mm and print at room temperature.

[0059] The printing path is a grid structure, with a filament spacing of 300 μm. The printing platform movement speed is set to 10 mm / s. When printing ink A, a 365 nm ultraviolet LED light source (light intensity of 30 mW / cm²) is used. 2 Simultaneous in-situ curing of inks A and B is performed to crosslink PEGDA and form an insoluble three-dimensional network framework. Ink B is printed using the same parameters and does not require photocuring. Inks A and B are printed alternately layer by layer. The total number of layers printed is 6 (stacked structure ABABAB).

[0060] Step 3, Post-processing and “4D” conversion: After printing, place the sample in a 60°C vacuum drying oven for 24 hours to completely remove residual NMP solvent.

[0061] The dried solid electrolyte membrane (in its "3D state") was transferred to an argon-filled glove box (water and oxygen content <0.1 ppm). A standard lithium-ion battery electrolyte (1 M LiPF6 in EC / DMC / EMC = 1:1:1, vol%) was uniformly added to the membrane surface using a micro-droplet method, at a rate of 2% of the total polymer mass.

[0062] After standing for 30 minutes, the electrolyte membrane underwent a predetermined "4D" transformation: the soluble PPC component selectively dissolved and gelled under the trigger of a trace amount of electrolyte, forming a gel phase in situ, fully encapsulating and wetting the PEGDA crosslinked framework, and finally obtaining an adaptive microgel solid electrolyte that combines rigid support and flexible ion transport channels.

[0063] Step 4: Assemble the battery and test it.

[0064] Example 2 Step 1: Ink Preparation: Dissolve an insoluble backbone polymer precursor—such as polyethylene glycol diacrylate (PEGDA, molecular weight 400, crosslinking agent, 60 wt% of ink mass)—in N-methylpyrrolidone (NMP, solvent, 40 wt% of ink mass). Stir magnetically in a 60°C water bath for 6 hours to form a homogeneous, transparent, viscous solution. Then, add a photoinitiator—2-hydroxy-2-methyl-1-phenyl-1-propanone—to the above solution at 1.5 wt% of the total solid mass. Continue stirring for 0.5 hours under light-protected conditions to obtain the final photocurable 3D printing ink, designated ink A. A soluble gel polymer precursor, such as polypropylene carbonate (PPC, Mn=50,000, 80 wt% of the printing ink), was dissolved in N,N-dimethylformamide (DMF, solvent, 20 wt% of the printing ink) and magnetically stirred in a 60°C water bath for 6 hours to form a homogeneous, transparent, viscous solution. This ink is designated as B.

[0065] Step 2: 3D Printing: Load the prepared ink into the barrel of the pneumatic direct-write 3D printer. Select a conical nozzle with an inner diameter of 0.4 mm and print at room temperature. The printing path is a grid structure, and the filament spacing is set to 300 μm. The printing platform movement speed is set to 10 mm / s. When printing ink A, use a 365 nm wavelength ultraviolet LED light source (light intensity 30 mW / cm²). 2 Simultaneous in-situ curing of inks A and B is performed to crosslink PEGDA and form an insoluble three-dimensional network framework. Ink B is printed using the same parameters and does not require photocuring. Inks A and B are printed alternately layer by layer. The total number of layers printed is 6 (stacked structure ABABAB).

[0066] Step 3: Post-processing and "4D" conversion: After printing, the sample is placed in a 60°C vacuum drying oven for 24 hours to completely remove residual NMP solvent. The dried solid electrolyte membrane (at this point in "3D state") is transferred to an argon-filled glove box (water and oxygen content <0.1 ppm). Using a micro-droplet method, standard lithium-ion battery electrolyte (1 M LiPF6 in EC / DMC / EMC = 1:1:1, vol%) is uniformly added to the membrane surface at a rate of 4% of the total polymer mass.

[0067] After standing for 30 minutes, the electrolyte membrane underwent a predetermined "4D" transformation: the soluble PPC component selectively dissolved and gelled under the trigger of a trace amount of electrolyte, forming a gel phase in situ, fully encapsulating and wetting the PEGDA crosslinked framework, and finally obtaining an adaptive microgel solid electrolyte that combines rigid support and flexible ion transport channels.

[0068] Step 4: Assemble the battery and test it.

[0069] Example 3 Step 1: Ink Preparation: Dissolve an insoluble backbone polymer precursor—such as polyethylene glycol diacrylate (PEGDA, molecular weight 400, crosslinking agent, 60 wt% of ink mass)—in N-methylpyrrolidone (NMP, solvent, 40 wt% of ink mass). Stir magnetically in a 60°C water bath for 6 hours to form a homogeneous, transparent, viscous solution. Then, add a photoinitiator—2-hydroxy-2-methyl-1-phenyl-1-propanone—to the above solution at 1.5 wt% of the total solid mass. Continue stirring for 0.5 hours under light-protected conditions to obtain the final photocurable 3D printing ink, designated ink A.

[0070] A soluble gel polymer precursor, such as polypropylene carbonate (PPC, Mn=50,000, 80 wt% of the printing ink), was dissolved in N,N-dimethylformamide (DMF, solvent, 20 wt% of the printing ink) and magnetically stirred in a 60°C water bath for 6 hours to form a homogeneous, transparent, viscous solution. This ink is designated as B.

[0071] Step 2, 3D Printing: Load the prepared ink into the cartridge of the pneumatic direct-write 3D printer. Select a conical nozzle with an inner diameter of 0.4 mm and print at room temperature. The printing path is a grid structure, and the filament spacing is set to 300 μm. The printing platform movement speed is set to 10 mm / s. When printing ink A, use a 365 nm wavelength ultraviolet LED light source (light intensity 30 mW / cm²). 2 Simultaneous in-situ curing of inks A and B is performed to crosslink PEGDA and form an insoluble three-dimensional network framework. Ink B is printed using the same parameters and does not require photocuring. Inks A and B are printed alternately layer by layer. The total number of layers printed is 6 (stacked structure ABABAB).

[0072] Step 3, Post-processing and "4D" Transformation: After printing, the sample was placed in a 60°C vacuum drying oven for 24 hours to completely remove residual NMP solvent. The dried solid electrolyte membrane (at this point in the "3D state") was transferred to an argon-filled glove box (water and oxygen content <0.1 ppm). Using a micro-droplet method, standard lithium-ion battery electrolyte (1 M LiPF6 in EC / DMC / EMC = 1:1:1, vol%) was uniformly added to the membrane surface at a volume of 6% of the total polymer mass. After standing for 30 minutes, the electrolyte membrane underwent the preset "4D" transformation: the soluble PPC component selectively dissolved and gelled under the trigger of the micro-electrolyte, forming a gel phase in situ, fully encapsulating and wetting the PEGDA crosslinked backbone, ultimately obtaining an adaptive microgel solid electrolyte with both rigid support and flexible ion transport channels.

[0073] Step 4: Assemble the battery and test it.

[0074] Example 4 Step 1: Preparation of Printing Ink: Dissolve an insoluble backbone polymer precursor—such as polyethylene glycol diacrylate (PEGDA, molecular weight 400, crosslinking agent, 60 wt% of printing ink mass)—in N-methylpyrrolidone (NMP, solvent, 40 wt% of printing ink mass). Stir magnetically in a 60°C water bath for 6 hours to form a homogeneous, transparent, viscous solution. Then, add a photoinitiator—2-hydroxy-2-methyl-1-phenyl-1-propanone—to the above solution at 1.5 wt% of the total solid mass. Continue stirring for 0.5 hours under light-protected conditions to obtain the final photocurable 3D printing ink, ink number A. A soluble gel polymer precursor, such as polypropylene carbonate (PPC, Mn=50,000, 80 wt% of the printing ink), was dissolved in N,N-dimethylformamide (DMF, solvent, 20 wt% of the printing ink) and magnetically stirred in a 60°C water bath for 6 hours to form a homogeneous, transparent, viscous solution. This ink is designated as B.

[0075] Step 2, 3D Printing: Load the prepared ink into the cartridge of the pneumatic direct-write 3D printer. Select a conical nozzle with an inner diameter of 0.4 mm and print at room temperature. The printing path is a grid structure, and the filament spacing is set to 300 μm. The printing platform movement speed is set to 10 mm / s. When printing ink A, use a 365 nm wavelength ultraviolet LED light source (light intensity 30 mW / cm²). 2Simultaneous in-situ curing of inks A and B is performed to crosslink PEGDA and form an insoluble three-dimensional network framework. Ink B is printed using the same parameters and does not require photocuring. Inks A and B are printed alternately layer by layer. The total number of layers printed is 6 (stacked structure ABABAB).

[0076] Step 3, Post-processing and "4D" Transformation: After printing, the sample was placed in a 60°C vacuum drying oven for 24 hours to completely remove residual NMP solvent. The dried solid electrolyte membrane (at this point in the "3D state") was transferred to an argon-filled glove box (water and oxygen content <0.1 ppm). Using a micro-droplet method, standard lithium-ion battery electrolyte (1 M LiPF6 in EC / DMC / EMC = 1:1:1, vol%) was uniformly added to the membrane surface, with the added amount being 8% of the total polymer mass. After standing for 30 minutes, the electrolyte membrane underwent the preset "4D" transformation: the soluble PPC component selectively dissolved and gelled under the trigger of the micro-electrolyte, forming a gel phase in situ, fully encapsulating and wetting the PEGDA crosslinked backbone, ultimately obtaining an adaptive microgel solid electrolyte with both rigid support and flexible ion transport channels.

[0077] Step 4: Assemble the battery and test it.

[0078] Example 5 Step 1: Preparation of Printing Ink: Dissolve an insoluble backbone polymer precursor—such as polyethylene glycol diacrylate (PEGDA, molecular weight 400, crosslinking agent, 60 wt% of printing ink mass)—in N-methylpyrrolidone (NMP, solvent, 40 wt% of printing ink mass). Stir magnetically in a 60°C water bath for 6 hours to form a homogeneous, transparent, viscous solution. Then, add a photoinitiator—2-hydroxy-2-methyl-1-phenyl-1-propanone—to the above solution at 1.5 wt% of the total solid mass. Continue stirring for 0.5 hours under light-protected conditions to obtain the final photocurable 3D printing ink, ink number A. A soluble gel polymer precursor, such as polypropylene carbonate (PPC, Mn=50,000, 80 wt% of the printing ink), was dissolved in N,N-dimethylformamide (DMF, solvent, 20 wt% of the printing ink) and magnetically stirred in a 60°C water bath for 6 hours to form a homogeneous, transparent, viscous solution. This ink is designated as B.

[0079] Step 2, 3D Printing: Load the prepared ink into the cartridge of the pneumatic direct-write 3D printer. Select a conical nozzle with an inner diameter of 0.4 mm and print at room temperature. The printing path is a grid structure, and the filament spacing is set to 300 μm. The printing platform movement speed is set to 10 mm / s. When printing ink A, use a 365 nm wavelength ultraviolet LED light source (light intensity 30 mW / cm²). 2 Simultaneous in-situ curing of inks A and B is performed to crosslink PEGDA and form an insoluble three-dimensional network framework. Ink B is printed using the same parameters and does not require photocuring. Inks A and B are printed alternately layer by layer. The total number of layers printed is 3 (the stacking structure is ABA).

[0080] Step 3, Post-processing and "4D" Transformation: After printing, the sample was placed in a 60°C vacuum drying oven for 24 hours to completely remove residual NMP solvent. The dried solid electrolyte membrane (at this point in the "3D state") was transferred to an argon-filled glove box (water and oxygen content <0.1 ppm). Using a micro-droplet method, standard lithium-ion battery electrolyte (1 M LiPF6 in EC / DMC / EMC = 1:1:1, vol%) was uniformly added to the membrane surface at a volume of 6% of the total polymer mass. After standing for 30 minutes, the electrolyte membrane underwent the preset "4D" transformation: the soluble PPC component selectively dissolved and gelled under the trigger of the micro-electrolyte, forming a gel phase in situ, fully encapsulating and wetting the PEGDA crosslinked backbone, ultimately obtaining an adaptive microgel solid electrolyte with both rigid support and flexible ion transport channels.

[0081] Step 4: Assemble the battery and test it.

[0082] Example 6 Step 1: Preparation of Printing Ink: Dissolve an insoluble backbone polymer precursor—such as polyethylene glycol diacrylate (PEGDA, molecular weight 400, crosslinking agent, 60 wt% of printing ink mass)—in N-methylpyrrolidone (NMP, solvent, 40 wt% of printing ink mass). Stir magnetically in a 60°C water bath for 6 hours to form a homogeneous, transparent, viscous solution. Then, add a photoinitiator—2-hydroxy-2-methyl-1-phenyl-1-propanone—to the above solution at 1.5 wt% of the total solid mass. Continue stirring for 0.5 hours under light-protected conditions to obtain the final photocurable 3D printing ink, ink number A. A soluble gel polymer precursor, such as polypropylene carbonate (PPC, Mn=50,000, 80 wt% of the printing ink), was dissolved in N,N-dimethylformamide (DMF, solvent, 20 wt% of the printing ink) and magnetically stirred in a 60°C water bath for 6 hours to form a homogeneous, transparent, viscous solution. This ink is designated as B.

[0083] Step 2, 3D Printing: Load the prepared ink into the cartridge of the pneumatic direct-write 3D printer. Select a conical nozzle with an inner diameter of 0.4 mm and print at room temperature. The printing path is a grid structure, and the filament spacing is set to 300 μm. The printing platform movement speed is set to 10 mm / s. When printing ink A, use a 365 nm wavelength ultraviolet LED light source (light intensity 30 mW / cm²). 2 Simultaneous in-situ curing of inks A and B is performed to crosslink PEGDA and form an insoluble three-dimensional network framework. Ink B is printed using the same parameters and does not require photocuring. Inks A and B are printed alternately layer by layer. The total number of layers printed is 9 (stack structure ABABABABA).

[0084] Step 3, Post-processing and "4D" Transformation: After printing, the sample was placed in a 60°C vacuum drying oven for 24 hours to completely remove residual NMP solvent. The dried solid electrolyte membrane (at this point in the "3D state") was transferred to an argon-filled glove box (water and oxygen content <0.1 ppm). Using a micro-droplet method, standard lithium-ion battery electrolyte (1 M LiPF6 in EC / DMC / EMC = 1:1:1, vol%) was uniformly added to the membrane surface at a volume of 6% of the total polymer mass. After standing for 30 minutes, the electrolyte membrane underwent the preset "4D" transformation: the soluble PPC component selectively dissolved and gelled under the trigger of the micro-electrolyte, forming a gel phase in situ, fully encapsulating and wetting the PEGDA crosslinked backbone, ultimately obtaining an adaptive microgel solid electrolyte with both rigid support and flexible ion transport channels.

[0085] Step 4: Assemble the battery and test it.

[0086] Example 7: Step 1: Preparation of Printing Ink: Dissolve an insoluble backbone polymer precursor—such as polyethylene glycol diacrylate (PEGDA, molecular weight 400, crosslinking agent, 60 wt% of printing ink mass)—in N-methylpyrrolidone (NMP, solvent, 40 wt% of printing ink mass). Stir magnetically in a 60°C water bath for 6 hours to form a homogeneous, transparent, viscous solution. Then, add a photoinitiator—2-hydroxy-2-methyl-1-phenyl-1-propanone—to the above solution at 1.5 wt% of the total solid mass. Continue stirring for 0.5 hours under light-protected conditions to obtain the final photocurable 3D printing ink, ink number A. A soluble gel polymer precursor, such as polypropylene carbonate (PPC, Mn=50,000, 80 wt% of the printing ink), was dissolved in N,N-dimethylformamide (DMF, solvent, 20 wt% of the printing ink) and magnetically stirred in a 60°C water bath for 6 hours to form a homogeneous, transparent, viscous solution. This ink is designated as B.

[0087] Step 2, 3D Printing: Load the prepared ink into the cartridge of the pneumatic direct-write 3D printer. Select a conical nozzle with an inner diameter of 0.4 mm and print at room temperature. The printing path is a grid structure, and the filament spacing is set to 300 μm. The printing platform movement speed is set to 10 mm / s. When printing ink A, use a 365 nm wavelength ultraviolet LED light source (light intensity 30 mW / cm²). 2 Simultaneous in-situ curing of inks A and B is performed to crosslink PEGDA and form an insoluble three-dimensional network framework. Ink B is printed using the same parameters and does not require photocuring. Inks A and B are printed alternately layer by layer. The total number of layers printed is 6 (stacked structure ABABAB).

[0088] Step 3, Post-processing and "4D" Transformation: After printing, the sample was placed in a 60°C vacuum drying oven for 24 hours to completely remove residual NMP solvent. The dried solid electrolyte membrane (in its "3D state") was transferred to an argon-filled glove box (water and oxygen content <0.1 ppm). Using a micro-droplet method, standard lithium-ion battery electrolyte (1 M LiPF6 in EC / DMC / EMC = 1:1:1, vol%) was uniformly added to the membrane surface at a volume of 6% of the total polymer mass. After standing for 10 minutes, the electrolyte membrane underwent the preset "4D" transformation: the soluble PPC component selectively dissolved and gelled under the triggering of the micro-electrolyte, forming a gel phase in situ, fully encapsulating and wetting the PEGDA crosslinked backbone, ultimately obtaining an adaptive microgel solid electrolyte with both rigid support and flexible ion transport channels.

[0089] Step 4: Assemble the battery and test it.

[0090] Example 8 Step 1: Preparation of Printing Ink: Dissolve an insoluble backbone polymer precursor—such as polyethylene glycol diacrylate (PEGDA, molecular weight 400, crosslinking agent, 60 wt% of printing ink mass)—in N-methylpyrrolidone (NMP, solvent, 40 wt% of printing ink mass). Stir magnetically in a 60°C water bath for 6 hours to form a homogeneous, transparent, viscous solution. Then, add a photoinitiator—2-hydroxy-2-methyl-1-phenyl-1-propanone—to the above solution at 1.5 wt% of the total solid mass. Continue stirring for 0.5 hours under light-protected conditions to obtain the final photocurable 3D printing ink, ink number A. A soluble gel polymer precursor, such as polypropylene carbonate (PPC, Mn=50,000, 80 wt% of the printing ink), was dissolved in N,N-dimethylformamide (DMF, solvent, 20 wt% of the printing ink) and magnetically stirred in a 60°C water bath for 6 hours to form a homogeneous, transparent, viscous solution. This ink is designated as B.

[0091] Step 2, 3D Printing: Load the prepared ink into the cartridge of the pneumatic direct-write 3D printer. Select a conical nozzle with an inner diameter of 0.4 mm and print at room temperature. The printing path is a grid structure, and the filament spacing is set to 300 μm. The printing platform movement speed is set to 10 mm / s. When printing ink A, use a 365 nm wavelength ultraviolet LED light source (light intensity 30 mW / cm²). 2 Simultaneous in-situ curing of inks A and B is performed to crosslink PEGDA and form an insoluble three-dimensional network framework. Ink B is printed using the same parameters and does not require photocuring. Inks A and B are printed alternately layer by layer. The total number of layers printed is 6 (stacked structure ABABAB).

[0092] Step 3, Post-processing and "4D" Transformation: After printing, the sample was placed in a 60°C vacuum drying oven for 24 hours to completely remove residual NMP solvent. The dried solid electrolyte membrane (in its "3D state") was transferred to an argon-filled glove box (water and oxygen content <0.1 ppm). Using a micro-droplet method, standard lithium-ion battery electrolyte (1 M LiPF6 in EC / DMC / EMC = 1:1:1, vol%) was uniformly added to the membrane surface at a volume of 6% of the total polymer mass. After standing for 60 minutes, the electrolyte membrane underwent the preset "4D" transformation: the soluble PPC component selectively dissolved and gelled under the trigger of the micro-electrolyte, forming a gel phase in situ, fully encapsulating and wetting the PEGDA crosslinked backbone, ultimately obtaining an adaptive microgel solid electrolyte with both rigid support and flexible ion transport channels.

[0093] Step 4: Assemble the battery and test it.

[0094] Specifically, in Examples 1-8 above, the positive electrode of the solid-state battery is prepared using polymer PVDF5130 as the positive electrode binder, lithium iron phosphate as the active material, and conductive carbon black as the conductive agent. The negative electrode is lithium metal.

[0095] The batteries for the vegetation in Examples 1-8 above were tested at 25°C for 300 cycles with a capacity of 0.5C. The specific test structure is shown in Table 1 below: Table 1 As shown in Table 1 above, in Examples 1-8, when the electrolyte accounts for 6% of the polymer matrix by mass, the total number of printed layers is 6, and the battery resting time is 60 minutes, the battery achieves the highest capacity retention rate of 97.4% after 300 cycles at 25°C. This indicates that factors such as the electrolyte ratio, the number of printed layers, and the battery resting time significantly affect the cycle performance of solid-state batteries.

[0096] In terms of electrolyte ratio, when the total number of printed layers and the battery resting time are fixed at 6 layers and 30 minutes, the battery cycle capacity retention rate gradually increases as the electrolyte ratio increases from 2% to 6%, reaching 97.1% at a ratio of 6%. However, when it continues to increase to 8%, the retention rate decreases, indicating that there is a suitable range for electrolyte ratio, and more is not necessarily better.

[0097] Analyzing the total number of printed layers, when the electrolyte ratio is fixed at 6% and the battery resting time is 30 minutes, the battery cycle capacity retention rate is relatively high when the total number of printed layers is 6, lower when the total number of printed layers is 3, and higher when the total number of printed layers is 9, but slightly lower than the optimal value of 6 layers. This may mean that there is an optimal value for the number of printed layers, and too few or too many layers will affect the battery performance.

[0098] Regarding battery resting time, when the electrolyte content is 6% and the total number of printed layers is 6, the battery cycle capacity retention rate is higher when the resting time is 60 minutes than when it is 10 minutes and 30 minutes, indicating that appropriately extending the battery resting time helps improve the battery's cycle performance. Specifically, in practice, considering that soluble polymers need a certain amount of time to completely dissolve and achieve uniform coating of the polymer framework after contacting the electrolyte, the gel coating effect is not strong when the battery is rested for less than half an hour; the battery performance is better when rested for more than half an hour. The above experimental data highlights the dynamic evolution of the gel solid electrolyte in 4D printing over time, which also means that the performance of solid-state batteries can be further optimized by reasonably controlling the battery resting time. In actual production and applications, we can precisely set the battery resting time according to different needs and conditions to fully leverage the advantages of gel solid electrolytes in 4D printing.

[0099] In summary, by reasonably adjusting parameters such as the electrolyte-to-polymer matrix mass ratio, the total number of printed layers, and the battery settling time, the cycle performance and stability of solid-state batteries can be effectively improved, providing an important reference for the practical application and further optimization of solid-state batteries.

[0100] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A 4D-printed gel solid electrolyte, characterized in that, A 4D-printed gel solid electrolyte is formed by adding electrolyte dropwise after the solid electrolyte is printed using a 3D printer. The solid electrolyte includes: Soluble polymers include at least one of the following: polymers containing carbonate groups, polymers containing ether bonds, and polymers containing ester groups; Photoinitiator; Insoluble polymers include at least one of polyolefins, fluoropolymers, engineering plastics and high-performance polymers, highly cross-linked polymer networks, or inorganic-organic hybrid polymers.

2. The 4D printing gel solid electrolyte according to claim 1, characterized in that, The carbonate-based polymer includes at least one of polyethylene carbonate, polypropylene carbonate, and aliphatic polycarbonate; The ether-containing polymer includes at least one of polyethylene oxide, polyethylene glycol, or polypropylene oxide with a molecular weight of 1000 g / mol to 1000000 g / mol; The ester-containing polymer includes at least one of polymethyl methacrylate, polycaprolactone, and polyvinyl acetate.

3. The 4D printing gel solid electrolyte according to claim 1, characterized in that, The photoinitiator is 2-hydroxy-2-methyl-1-phenyl-1-propanone, which initiates a cross-linking reaction of the insoluble polymer under ultraviolet irradiation to form a three-dimensional network skeleton.

4. The 4D printing gel solid electrolyte according to claim 1, characterized in that, The polyolefins include at least one of polyethylene and polypropylene; The fluoropolymer includes at least one of polytetrafluoroethylene and perfluorosulfonic acid resin; The engineering plastics and high-performance polymers include at least one of polyimide, polybenzimidazole, and polyetheretherketone; The highly cross-linked polymer network includes at least one of cross-linked polyacrylate, cross-linked epoxy resin, phenolic resin, and urea-formaldehyde resin; The inorganic-organic hybrid polymer includes at least one of polysiloxane alkyl composite materials and ceramic nanoparticle composite polymers.

5. A method for printing gel solid electrolytes in 4D printing, characterized in that, Includes the following steps: Step S1: Dissolve the insoluble polymer in a first solvent and stir to form a viscous solution. Prepare a photocurable printing ink A by mixing the viscous solution with a photoinitiator and print the insoluble skeleton using a 3D printer. Step S2: Dissolve the soluble polymer in a second solvent and stir to form printing ink B. Then, alternately print the printing ink B with the insoluble skeleton using the 3D printer to form a solid electrolyte membrane. Step S3: Dry the solid electrolyte membrane, and then uniformly drop electrolyte onto the surface of the solid electrolyte membrane to obtain a 4D printed gel solid electrolyte.

6. The 4D printing method for gel solid electrolytes according to claim 5, characterized in that, In step S1, the insoluble polymer accounts for 50wt%-60wt% of the mass of printing ink A; the first solvent is N-methylpyrrolidone, and the first solvent accounts for 30wt%-40wt% of the mass of printing ink A. The insoluble polymer and the first solvent were magnetically stirred in a 60°C water bath for 6 hours to form the viscous solution; The amount of photoinitiator added to the viscous solution is 1wt%-5wt% of the total mass of the printing ink A. After the photoinitiator is added to the viscous solution, it is stirred for 10-30 minutes under dark conditions to obtain the photocured printing ink A.

7. The 4D printing method for gel solid electrolytes according to claim 5, characterized in that, The second solvent is N,N-dimethylformamide, and the second solvent accounts for 20wt%-40wt% of the mass ratio of the printing ink B; the soluble polymer accounts for 60wt%-80wt% of the mass ratio of the printing ink B. The second solvent and the soluble polymer are magnetically stirred in a 60°C water bath for 6 hours to form the printing ink B.

8. The 4D printing method for gel solid electrolytes according to claim 5, characterized in that, The 3D printer is a pneumatic direct-write 3D printer. The 3D printer adds the prepared printing ink A and printing ink B into the 3D printer barrel respectively, and prints at room temperature through a conical nozzle with an inner diameter of 0.4mm. The printing path of the 3D printer is a grid structure, the single filament spacing is set to 300 μm, and the moving speed of the 3D printer is set to 30-150 mm / s. In step S1, when the 3D printer prints the insoluble skeleton, a 365 nm ultraviolet LED light source is used for simultaneous in-situ curing, and the light intensity of the ultraviolet LED light source is 30 mW / cm². 2 ; The insoluble polymer is cross-linked to form an insoluble three-dimensional network framework by the ultraviolet LED light source.

9. The 4D printing method for gel solid electrolytes according to claim 5, characterized in that, The solid electrolyte membrane obtained in step S3 is placed in a vacuum drying oven at 60°C for 24 hours; The dried solid electrolyte membrane is transferred to an argon-filled glove box, and electrolyte is uniformly added to the surface of the solid electrolyte membrane using a micro-drop method. The amount of electrolyte added is 2%-5% of the total mass of the insoluble and soluble polymers.

10. A solid-state battery, comprising a 4D-printed gel solid electrolyte, a positive electrode, and a negative electrode as described in any one of claims 1-4, characterized in that, The positive electrode active material in the positive electrode sheet includes layered oxides, lithium iron phosphate and Prussian blue analogs or polyanionic compounds. The negative electrode active material in the negative electrode sheet includes lithium metal, lithium titanate, hard carbon or soft carbon, and silicon-based materials.

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