All-solid-state potassium ion battery electrolyte as well as preparation method and application thereof
The polymer-based composite solid electrolyte membrane prepared by photocuring method solves the safety hazards of liquid electrolytes in potassium ion batteries and the scarcity of lithium resources, and achieves high safety and high energy density of all-solid potassium ion batteries.
Patent Information
- Application Number
- CN202510334665.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-20
- Publication Date
- 2025-06-20
AI Technical Summary
The use of liquid electrolytes in existing potassium ion batteries poses safety risks, such as gas production, ignition and explosion, and the scarcity and unbalanced distribution of lithium resources are becoming increasingly prominent, resulting in challenges in the cost and supply stability of lithium-ion batteries.
The polymer-based composite solid electrolyte membrane prepared by the photocuring method is stirred and dispersed uniformly in a low water oxygen state using potassium salt, liquid polymer monomer, nanoceramic powder and photoinitiator to form a solid electrolyte precursor slurry, and polymerization is carried out under ultraviolet light to obtain a solid polymer electrolyte membrane.
It realizes high safety performance of all-solid potassium ion batteries, avoids safety hazards of liquid electrolytes, improves the intrinsic energy density and stability of the battery, and reduces the cost of raw materials and the complexity of the preparation process.
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Figure CN120184343A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of potassium ion batteries, and in particular relates to an all-solid-state potassium ion battery electrolyte and a preparation method and application thereof. Background Art
[0002] Against the backdrop of profound changes in today's global energy landscape, efficient, safe and sustainable energy storage technology has become one of the core elements to promote energy transformation and the development of modern science and technology. Lithium-ion batteries are widely used in many fields such as portable electronic devices, electric vehicles and renewable energy storage due to their advantages such as high energy density and long cycle life. However, as the global demand for clean energy grows exponentially, the scarcity and uneven distribution of lithium resources have become increasingly prominent, resulting in rising costs and severe challenges to supply stability. These limitations have prompted researchers to favor new secondary batteries such as sodium-ion batteries, potassium-ion batteries, and magnesium-ion batteries to meet the needs of large-scale energy storage and diversified energy applications in the future. Among them, potassium-ion batteries have the advantages of abundant resources, environmental friendliness, and K + / K standard electrode has low potential and shows research value and application potential.
[0003] At present, potassium ion batteries mainly use non-aqueous liquid electrolytes composed of organic carbonate solvents and potassium salts. Although the ion transfer rate of liquid electrolytes is fast, there are still thermal runaway safety hazards such as gas production, fire and explosion during continuous charging and discharging. However, all-solid-state batteries use solid electrolytes instead of traditional volatile and flammable liquid electrolytes, which fundamentally solves the safety hazards of electrolyte leakage and fire in batteries, and provides more reliable guarantees for the large-scale application of batteries. In addition, potassium metal with low electrode potential can be used as the negative electrode in solid-state batteries to further improve the intrinsic energy density of the battery system. Therefore, the development of a new type of polymer-based composite solid electrolyte to construct an all-solid-state potassium ion battery is of great significance to the development of new high-energy-density and high-safety battery systems. Summary of the invention
[0004] The purpose of the present invention is to provide an all-solid-state potassium ion battery electrolyte membrane and a preparation method and application thereof in view of the above-mentioned deficiencies in the prior art. The solid electrolyte membrane prepared by the photocuring method has low raw material cost and simple preparation process, and can be scaled up for production. No organic solvent and electrolyte need to be added during the preparation process, thereby effectively improving the safety performance of the solid-state battery.
[0005] To achieve the above object, the present invention adopts the following technical solution: The first aspect of the present invention is to provide a method for preparing an all-solid-state potassium ion battery electrolyte membrane, the preparation method comprising the following steps: S1. Stir and disperse potassium salt, liquid-phase polymer monomer, nano-ceramic powder, and photoinitiator evenly under a low water-oxygen state to obtain a solid electrolyte precursor slurry; the molar ratio of the ethylene oxide functional group segment in the liquid-phase polymer monomer to the potassium salt is 14:1 to 22:1, and the low water-oxygen state means the water-oxygen value is not higher than 0.1 ppm; S2. Subject the precursor slurry to a polymerization reaction under ultraviolet light irradiation to obtain a solid polymer electrolyte.
[0006] Further, the potassium salt is any one of KFSI, KTFSI, KClO4, and KPF6.
[0007] Further, the liquid-phase polymer monomer is polyethylene glycol methyl ether acrylate or polyethylene glycol diacrylate.
[0008] Further, the nano-ceramic powder is any one of alumina, silica, or magnesia.
[0009] Further, the photoinitiator is benzoin dimethyl ether or 1-hydroxycyclohexyl phenyl ketone.
[0010] Further, the mass ratio of the nano-ceramic powder is 2% to 20% of the mass of the liquid-phase polymer monomer.
[0011] Further, the content of the photoinitiator is 0.2% to 1% of the mass of the polymer monomer.
[0012] Further, the stirring and dispersing time is 1 h to 10 h.
[0013] Further, the substrate is any one of a polytetrafluoroethylene plate, copper foil, and aluminum foil.
[0014] The second aspect of the present invention is to provide a solid electrolyte membrane prepared by the above preparation method.
[0015] Further, the thickness of the solid electrolyte membrane is 50 to 200 μm.
[0016] Further, the ionic conductivity of the solid electrolyte membrane ranges from 6.2×10 -5 ~2.3×10 -4 S / cm, and the tensile deformation rate can reach 180%.
[0017] The third aspect of the present invention is to provide a potassium-ion battery, including a positive electrode, a negative electrode, and an electrolyte layer disposed between the positive electrode and the negative electrode, and the electrolyte layer includes the above solid electrolyte membrane.
[0018] Further, the negative electrode is a potassium metal negative electrode or a graphite negative electrode.
[0019] Further, the positive electrode is a PTCDA positive electrode or a Prussian blue positive electrode.
[0020] Compared with the prior art, the beneficial effects brought by the technical solution provided by the present invention are as follows: (1) The solid-state potassium-ion battery electrolyte membrane provided by the present invention is formed by the polymerization of liquid-phase polymer monomers, avoiding the introduction of organic electrolytes, and realizing a highly efficient and stable solid-state electrolyte membrane for potassium-ion batteries; by introducing nano-ceramic powders, the electrode / electrolyte interface compatibility of the solid electrolyte is improved, and an efficient ion transport channel is constructed through the continuous porous nature of the nano-ceramic powders, improving the ionic conductivity of the electrolyte and realizing stable solid-state battery performance; moreover, the mechanical properties of this solid electrolyte membrane are enhanced, and the operability of the electrolyte membrane during the preparation of the all-solid-state battery is improved.
[0021] (2) The raw material cost of the solid electrolyte membrane prepared by the present invention by the photocuring method is low, the preparation process is simple, and it can be scaled up for production. There is no need to add organic solvents and electrolytes during the preparation process, effectively improving the safety performance of the solid-state battery.
[0022] (3) The all-solid-state potassium-ion battery constructed by matching the positive and negative electrode materials with the all-solid-state potassium-ion battery electrolyte membrane prepared by the present invention can obtain stable battery cycling performance. Description of the Drawings
[0023] Figure 1 It is the scanning electron microscope morphology structure and its element distribution spectrum of the solid potassium-ion polymer electrolyte prepared in Example 1 of the present invention; Figure 2 It is the test result of the tensile deformation performance of the solid potassium-ion polymer electrolyte prepared in Example 1 and Example 2 of the present invention; Figure 3 It is for the potassium metal symmetric battery in Example 1 and Example 2 of the present invention at a current density of 0.1 mA / cm 2 Current density, symmetric battery performance diagram at 60 °C; Figure 4 It is the voltage stability window analysis curve of Example 1 and Example 2 of the present invention; Figure 5 It is the limiting current density of the potassium metal symmetric battery in Example 1, Example 2, Example 11, and Example 12 of the present invention; Figure 6 It is the charge and discharge curve of the all-solid-state potassium-ion battery in Example 12 of the present invention at a current density of 100 mA / g and 60 °C; Figure 7 It is the charge and discharge cycling performance diagram of the all-solid-state potassium-ion battery in Example 12 of the present invention at a current density of 100 mA / g and 60 °C. Detailed Embodiments To make the objectives, technical solutions and advantages of the present invention clearer, the following further describes in detail the specific embodiments of the present invention in conjunction with specific embodiments and the accompanying drawings. For those not specifying specific test methods, instrument devices or conditions in the embodiments, they shall all be carried out according to the technologies or conditions described in the literature in this field or according to the product specifications. For those reagents or instruments not specifying the manufacturer, they are all conventional products that can be obtained through commercial purchase.
[0024] Example 1 This example provides a solid-state electrolyte membrane for an all-solid-state potassium-ion battery and a preparation method therefor.
[0025] Potassium bis(fluorosulfonyl)imide (KFSI), porous nanoscale Al2O3 powder (particle size 5 - 20 nm), and a small amount of initiator benzoin dimethyl ether (DMPA) are added to poly(ethylene glycol) methyl ether acrylate (PEGMEA). The molar ratio of the ethylene oxide functional group (EO) in the polymer monomer to the potassium salt is adjusted to 20:1, and the mass percentages of each component are as shown in Table 1 (note: no organic solvent is introduced in this process, which is the key to forming an all-solid-state electrolyte system). It is stirred at room temperature for 6 hours to obtain a uniform polymer precursor slurry. Subsequently, the slurry is evenly spread on a polytetrafluoroethylene membrane in an inert atmosphere glove box, controlling the water and oxygen value in the glove box to be less than 0.1 ppm, and then a photocuring reaction is started under the irradiation of an ultraviolet lamp for 1 h. Then, the cured polymer composite electrolyte is peeled off from the polytetrafluoroethylene membrane to obtain a composite solid-state electrolyte membrane with better flexibility.
[0026] Table 1. Solid-state electrolyte components of Example 1
[0027] The above solid-state electrolyte membrane is placed under a scanning electron microscope to observe its surface morphology, as Figure 1 shown, the surface morphology structure is flat, the alumina ceramic powder is evenly distributed in the polymer, and the elements K, Al, O, S, and F are all uniformly distributed.
[0028] The ionic conductivity of the prepared solid-state potassium-ion electrolyte is tested: In a 2032 coin cell, a solid-state electrolyte film with a thickness of 180 μm and a diameter of 16 mm is clamped with a stainless steel sheet, and its impedance value is tested using an electrochemical workstation. According to the formula: σ = L / S·R, where S is the area of the solid-state electrolyte film, L is its thickness, and R is its impedance value. The ionic conductivities of the solid-state electrolyte film at 30 °C, 40 °C, 50 °C, and 60 °C are respectively 0.6×10 -4 S / cm, 1.1×10 -4 S / cm, 1.7×10 -4 S / cm, 3.3×10-4 S / cm.
[0029] Example 2 This example provides a solid electrolyte membrane for an all-solid-state potassium-ion battery and a preparation method.
[0030] Basically the same as Example 1, the difference is that a solid electrolyte precursor solution is prepared, and the contents of polyethylene glycol methyl ether acrylate (PEGMEA) monomer, potassium bis(fluorosulfonyl)imide (KFSI), and photoinitiator DMPA are shown in Table 2. The molar ratio of the ethylene oxide segment (EO) to the potassium salt in the polymer monomer is adjusted to 20:1 (note: no ceramic additive is introduced in Example 2). After stirring evenly, photo-curing is carried out in an inert atmosphere glove box for 1 h. Then the solid electrolyte membrane is removed from the substrate.
[0031] Table 2. Solid electrolyte components of Example 2
[0032] The flexibility of the solid electrolytes of Example 1 and Example 2 was tested by mechanical stretching, and the results are as Figure 2 shown. The solid electrolyte of Example 1 exhibits far better deformation performance than that of Example 2. Its deformation rate can reach 180%, and the film of Example 1 can still return to its original shape after deformation, showing high elastic performance.
[0033] Potassium metal symmetric battery: The interfacial compatibility between the prepared solid electrolyte and the potassium metal negative electrode was tested: A potassium metal symmetric battery was assembled in an inert atmosphere glove box. Potassium metal negative electrode sheets of the same size were placed on both sides of the electrolyte to assemble a 2032 button battery. The battery was tested with a current density of 0.1 mA / cm 2 and a charge-discharge time of 1 h. The polarization voltage curves of the symmetric batteries of Example 1 and Example 2 are as Figure 3 shown. From this figure, it can be obtained that the glass and deposition behaviors of potassium metal are stable, indicating that this solid electrolyte has good compatibility with the potassium metal negative electrode.
[0034] Voltage stability window: The voltage stability windows of Example 1 and Example 2 were tested by the LSV method, and the results are as Figure 4 shown. Example 1 exhibits an electrolyte decomposition voltage value reaching 5 V.
[0035] Example 3 This example provides a solid electrolyte membrane for an all-solid-state potassium-ion battery and a preparation method.
[0036] Basically the same as Example 1, except that a fully solid-state electrolyte precursor solution is prepared, where the contents of polyethylene glycol methyl ether acrylate (PEGMEA) monomer, potassium bis(fluorosulfonyl)imide (KFSI), nanoscale Al2O3 powder, and photoinitiator DMPA are shown in Table 3. The molar ratio of the ethylene oxide chain segment (EO) to the potassium salt in the polymer monomer is adjusted to 20:1 (in this example, the content of the ceramic additive is reduced compared to Example 1). After stirring evenly, photo-curing is carried out in an inert atmosphere glove box for 1 h. Then, the solid-state electrolyte membrane is removed from the substrate.
[0037] Table 3. Solid-state electrolyte components of Example 3
[0038] Example 4 This example provides a solid-state electrolyte membrane for a fully solid-state potassium-ion battery and a preparation method.
[0039] Basically the same as Example 1, except that a fully solid-state electrolyte precursor solution is prepared, where the contents of polyethylene glycol methyl ether acrylate (PEGMEA) monomer, potassium bis(fluorosulfonyl)imide (KFSI), nanoscale Al2O3 powder, and photoinitiator DMPA are shown in Table 4. The molar ratio of the ethylene oxide chain segment (EO) to the potassium salt in the polymer monomer is adjusted to 20:1 (in this example, the content of the ceramic additive is increased compared to Example 1). After stirring evenly, photo-curing is carried out in an inert atmosphere glove box for 1 h. Then, the solid-state electrolyte membrane is removed from the substrate.
[0040] Table 4. Solid-state electrolyte components of Example 4
[0041] Example 5 This example provides a solid-state electrolyte membrane for a fully solid-state potassium-ion battery and a preparation method.
[0042] Basically the same as Example 1, except that a fully solid-state electrolyte precursor solution is prepared, where the contents of polyethylene glycol methyl ether acrylate (PEGMEA) monomer, potassium bis(fluorosulfonyl)imide (KFSI), nanoscale Al2O3 powder, and photoinitiator DMPA are shown in Table 5. The molar ratio of the ethylene oxide chain segment (EO) to the potassium salt in the polymer monomer is adjusted to 20:1. In this example, the content of the ceramic additive is further increased compared to Example 4. After stirring evenly, photo-curing is carried out in an inert atmosphere glove box for 1 h. Then, the solid-state electrolyte membrane is removed from the substrate.
[0043] Table 5. Solid-state electrolyte components of Example 5
[0044] Example 6 This example provides a solid electrolyte membrane for an all-solid-state potassium-ion battery and a preparation method thereof.
[0045] Basically the same as Example 1, the difference is that an all-solid-state electrolyte precursor solution is prepared, in which the contents of polyethylene glycol methyl ether acrylate (PEGMEA) monomer, potassium bis(fluorosulfonyl)imide (KFSI), and photoinitiator DMPA are shown in Table 6. The molar ratio of the ethylene oxide segment (EO) to the potassium salt in the polymer monomer is adjusted to 14:1. After stirring evenly, photo-curing is carried out in an inert atmosphere glove box, and the irradiation time is 1 h. Then the solid electrolyte membrane is removed from the substrate.
[0046] Table 6. Solid electrolyte components of Example 6
[0047] Example 7 This example provides a solid electrolyte membrane for an all-solid-state potassium-ion battery and a preparation method thereof.
[0048] Basically the same as Example 1, the difference is that an all-solid-state electrolyte precursor solution is prepared, in which the contents of polyethylene glycol methyl ether acrylate (PEGMEA) monomer, potassium bis(fluorosulfonyl)imide (KFSI), and photoinitiator DMPA are shown in Table 7. The molar ratio of the ethylene oxide segment (EO) to the potassium salt in the polymer monomer is adjusted to 16:1. After stirring evenly, photo-curing is carried out in an inert atmosphere glove box, and the irradiation time is 1 h. Then the solid electrolyte membrane is removed from the substrate.
[0049] Table 7. Solid electrolyte components of Example 7
[0050] Example 8 This example provides a solid electrolyte membrane for an all-solid-state potassium-ion battery and a preparation method thereof.
[0051] Basically the same as Example 1, the difference is that an all-solid-state electrolyte precursor solution is prepared, in which the contents of polyethylene glycol methyl ether acrylate (PEGMEA) monomer, potassium bis(fluorosulfonyl)imide (KFSI), and photoinitiator DMPA are shown in Table 8. The molar ratio of the ethylene oxide segment (EO) to the potassium salt in the polymer monomer is adjusted to 18:1. After stirring evenly, photo-curing is carried out in an inert atmosphere glove box, and the irradiation time is 1 h. Then the solid electrolyte membrane is removed from the substrate.
[0052] Table 8. Solid electrolyte components of Example 8
[0053] Example 9 This embodiment provides a solid electrolyte membrane for an all-solid-state potassium ion battery and a preparation method thereof.
[0054] Basically the same as Example 1, the difference is that an all-solid-state electrolyte precursor solution is prepared, and the contents of polyethylene glycol methyl ether acrylate (PEGMEA) monomer, potassium bis(fluorosulfonyl)imide (KFSI), and photoinitiator DMPA are shown in Table 9. The molar ratio of the ethylene oxide chain segment (EO) to the potassium salt in the polymer monomer is adjusted to 20:1. After stirring evenly, photo-curing is carried out in an inert atmosphere glove box for 1 h. Then, the solid electrolyte membrane is removed from the substrate.
[0055] Table 9. Solid electrolyte components of Example 9
[0056] The ionic conductivities of the solid electrolyte membranes prepared in Examples 1 to 9 are shown in Table 10: Table 10. Ionic conductivities of different examples
[0057] Example 10 This embodiment provides a solid electrolyte membrane for an all-solid-state potassium ion battery and a preparation method thereof.
[0058] Basically the same as Example 1, the difference is that an all-solid-state electrolyte precursor solution is prepared, and the contents of polyethylene glycol methyl ether acrylate (PEGMEA) monomer, potassium bis(fluorosulfonyl)imide (KFSI), nano-silica powder, and photoinitiator DMPA are shown in Table 11. The molar ratio of the ethylene oxide chain segment (EO) to the potassium salt in the polymer monomer is adjusted to 20:1. After stirring evenly, photo-curing is carried out in an inert atmosphere glove box for 1 h. Then, the solid electrolyte membrane is removed from the substrate.
[0059] Table 11. Solid electrolyte components of Example 10
[0060] Example 11 This embodiment provides a solid electrolyte membrane for an all-solid-state potassium ion battery and a preparation method thereof.
[0061] Basically the same as Example 1, the difference is that an all-solid-state electrolyte precursor solution is prepared, and the contents of polyethylene glycol methyl ether acrylate (PEGMEA) monomer, potassium bis(fluorosulfonyl)imide (KFSI), nano-magnesium oxide powder, and photoinitiator DMPA are shown in Table 12. The molar ratio of the ethylene oxide chain segment (EO) to the potassium salt in the polymer monomer is adjusted to 20:1. After stirring evenly, photo-curing is carried out in an inert atmosphere glove box for 1 h. Then, the solid electrolyte membrane is removed from the substrate.
[0062] Table 12. Solid electrolyte components of Example 11
[0063] Limiting current density test: The solid electrolyte films of Example 1, Example 2, Example 10, and Example 11 were assembled into symmetric cells and the limiting current density was tested. The results are as Figure 4 shown. The introduction of nanoscale porous alumina powder significantly improved the limiting current density of the solid electrolyte membrane and was superior to other inert ceramic fillers.
[0064] Example 12 0.35 g of organic cathode PTCDA (perylene-3,4,9,10-tetracarboxylic dianhydride), 0.1 g of conductive carbon black, 0.05 PVDF binder, and 2.5 g of organic solvent NMP were mixed into a slurry and stirred evenly. The slurry was cast onto the surface of aluminum foil by the doctor blade method and then dried in a forced-air oven at 60 °C. After complete drying, it was cut into positive electrode sheets.
[0065] The polymer monomer precursor solution of the components of Example 1 was prepared into a solid electrolyte film. Then, in an inert atmosphere glove box, a potassium metal anode, a solid electrolyte, and a PTCDA positive electrode sheet were assembled into a 2032 coin cell, and its electrochemical performance was tested at a temperature of 60 °C, a current density of 100 mA / g, and a charge-discharge voltage range of 1.5 - 3.0 V. Its charge-discharge curve and cycle stability are as Figure 5 and Figure 6 shown. The discharge specific capacity of this all-solid-state potassium ion battery can reach a capacity of 123 mAh / g, and there is still a specific capacity of 102 mAh / g after 200 cycles. This example shows that the all-solid-state potassium ion battery composed of this solid electrolyte has high research value and application potential.
[0066] Without conflict, the above embodiments and the features in the embodiments in this article may be combined with each other.
[0067] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.
Claims
1. A method for preparing an all-solid-state potassium ion battery electrolyte membrane, characterized in that: The preparation method comprises the following steps: S1. Stir and disperse potassium salt, liquid polymer monomer, nano-ceramic powder and photoinitiator in a low water and oxygen state to obtain a solid electrolyte precursor slurry; the molar ratio of the ethylene oxide functional group segment in the liquid polymer monomer to the potassium salt is 14:1-22:1, and the low water and oxygen state is a water and oxygen value not higher than 0.1ppm; S2. Pour the precursor slurry onto a substrate, and cause a polymerization reaction under ultraviolet light to obtain a solid electrolyte membrane.
2. The preparation method according to claim 1, characterized in that The potassium salt is any one of KFSI, KTFSI, KClO4 and KPF6; the liquid phase polymer monomer is polyethylene glycol methyl ether acrylate or polyethylene glycol diacrylate.
3. The preparation method according to claim 2, characterized in that: The nano ceramic powder is any one of aluminum oxide, silicon oxide or magnesium oxide; the photoinitiator is benzoin dimethyl ether or 1-hydroxycyclohexylphenyl methyl.
4. The preparation method according to claim 3, characterized in that: The mass ratio of the nano-ceramic powder is 2% to 20% of the mass of the liquid phase polymer monomer, the content of the photoinitiator is 0.2% to 1% of the mass of the polymer monomer, and the stirring and dispersing time is 1h to 10h.
5. The preparation method according to claim 1, characterized in that: The substrate is any one of polytetrafluoroethylene plate, copper foil and aluminum foil.
6. A solid electrolyte membrane prepared by the preparation method according to any one of claims 1 to 5.
7. The solid polymer electrolyte membrane according to claim 6, characterized in that The thickness of the solid electrolyte membrane is 50-200 μm.
8. The solid electrolyte membrane according to claim 7, characterized in that The ionic conductivity of the solid electrolyte membrane is increased from 6.2×10 -5 ~2.3×10 -4 S / cm, the tensile deformation rate can reach 180%.
9. A potassium ion battery comprising a positive electrode, a negative electrode and an electrolyte layer disposed between the positive electrode and the negative electrode, characterized in that: The electrolyte layer comprises the solid electrolyte membrane according to any one of claims 6 to 8.
10. The potassium ion battery according to claim 9, characterized in that The negative electrode is a potassium metal negative electrode or a graphite negative electrode, and the positive electrode is a PTCDA positive electrode or a Prussian blue positive electrode.