High-voltage ionic gel electrolyte and solid-state sodium ion battery containing electrolyte

Abstract

The invention provides a high-voltage ionic gel electrolyte and a solid-state sodium-ion battery containing the electrolyte, which are used for solving the problem that a good interface layer is difficult to form on the surface of an electrode when a solid-state polymer electrolyte in the current sodium-ion battery is under a high-voltage condition, so that the multiplying power and the cycle performance of the solid-state sodium battery under the high voltage are influenced. The high-voltage ionic gel electrolyte of the solid sodium-ion battery comprises basic ionic gel and an organic additive, the basic ionic gel is composed of inorganic salt, a polymer substrate and ionic liquid, the organic additive is R-SO3Na (the number of-SO3Na groups is one or more), R is alkyl, amino or aryl, the organic additive widens an electrochemical stability window of the ionic gel electrolyte, and the electrochemical stability of the ionic gel electrolyte is improved. And when being applied to the high-voltage sodium battery, the high-voltage sodium battery has relatively good ion transmission kinetics and rate capability.

Description

Technical Field

[0001] This invention belongs to the field of high-voltage sodium-ion batteries, and relates to a high-voltage ion gel electrolyte and a solid sodium-ion battery containing the electrolyte. Background Technology

[0002] Sodium-ion batteries are favored due to their low cost, abundant raw materials, and higher safety, and have achieved significant development in large-scale energy storage. However, their energy density remains a concern. One feasible method to improve energy density is to increase the charging cutoff voltage of sodium-ion batteries. However, when the battery operates at high voltages (>4.3 V), the degradation of liquid organic carbonate electrolytes accelerates, potentially posing safety hazards. Ion-gel polymer electrolytes inherently possess high safety and good electrochemical stability, effectively preventing electrolyte degradation in high-voltage solid-state sodium batteries. Therefore, using ion-gel electrolytes with a high voltage window is of great significance for improving the energy density of sodium-ion batteries.

[0003] Solid polymer electrolytes have a considerable electrochemical window, but it is not outstanding and cannot simultaneously satisfy the requirement of high ionic conductivity (>10). -3 S cm -1 The high ion transport number and good electrode / electrolyte interface of sodium-ion batteries make them unsuitable for stable cycling under high voltages over extended periods, hindering their application. While many reports exist on solid-state polymer electrolytes (SPEs) in the sodium-ion battery field, few have been published on SPEs that are compatible with high-voltage sodium-ion battery cathode materials (sodium vanadium fluorophosphate and sodium ferric sulfate). The primary reason is that the electrode-electrolyte interface undergoes more complex decomposition under high voltages, making it difficult to form a stable CEI at high voltages. This continuous degradation increases interfacial impedance, ultimately delaying sodium intercalation / deintercalation kinetics and resulting in poor battery performance. Currently, solid-state polymer electrolytes in sodium-ion batteries struggle to simultaneously achieve high electrochemical windows, room-temperature ionic conductivity, and sodium ion transport number. Furthermore, under high voltages, SPEs find it difficult to form a good CEI on the electrode surface, leading to poor ion transport kinetics and a suboptimal CEI, which further impacts the rate performance and cycle performance of solid-state batteries under high voltages.

[0004] Patent CN 117801152 A discloses a battery gel electrolyte and its preparation method, as well as a zinc-air battery. The battery gel electrolyte includes acrylic acid, sodium dodecylbenzenesulfonate, a strong alkali, deionized water, a crosslinking agent, an initiator, and an electrolyte; the electrolyte is a solution containing zinc salts. However, this zinc-air battery electrolyte suffers from low low-temperature cycling stability. One surface of the gel electrolyte is in close contact with the zinc anode. Because the sulfonic acid groups of the sodium dodecylbenzenesulfonate on the gel electrolyte surface can form coordination bonds with zinc ions on the zinc anode surface, the connection between the gel electrolyte and the zinc anode is strengthened, which is beneficial for electron transport (i.e., reducing interfacial impedance) and the orderly arrangement of zinc ions after reduction (specifically reducing the formation of zinc dendrites on the zinc anode surface). In this patent, the sulfonic acid groups, zinc anode, and solvent undergo some coordination and adsorption interactions, and the phenylalkyl groups in the sodium dodecylbenzenesulfonate also play a role, mainly addressing the problem of low zinc ion conductivity at low temperatures. Furthermore, this battery gel electrolyte is an aqueous solvent, which poses safety concerns when used in sodium-ion batteries. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention proposes a high-voltage ion gel electrolyte and a solid-state sodium-ion battery containing the electrolyte. Adding a small amount of organic additives to the electrolyte can improve the ion transport kinetics in the bulk electrolyte phase and effectively passivate the decomposition of sodium salts and ionic liquids in the electrolyte. Under high voltage, the optimized composition and formation of the CEI on the electrode surface forms a stable CEI layer, which helps to realize a high-voltage sodium-ion battery with good cycle performance and rate performance.

[0006] To achieve the above objectives, the technical solution of the present invention is implemented as follows: A high-pressure ion gel electrolyte comprises a basic ion gel consisting of an inorganic salt, a polymer substrate, and an ion liquid, and an organic additive, wherein the organic additive is a sodium sulfonate derivative.

[0007] Furthermore, the sodium sulfonate derivative has the structural formula R-SO3Na (the number of -SO3Na groups is one or more), where R is an alkyl, amino, or aryl group.

[0008] Furthermore, the alkyl group is -CH3 or -CH=CH2; the amino group is -NH2; and the aryl group is... Any one of them.

[0009] Furthermore, the specific structural formulas of the sodium sulfonate derivatives are: CH3SO3Na, CH2=CHSO3Na, NH2SO3Na, Any one of them.

[0010] Furthermore, the inorganic salt is sodium bis(trifluoromethanesulfonyl)imide; the polymer substrate is polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP); and the ionic liquid is 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide salt (EmimFSI).

[0011] Furthermore, the mass ratio of the polymer substrate (containing organic additives), ionic liquid, and inorganic salt is 0.5:0.6:(0.117~0.5), wherein the concentration of inorganic salt in the basic ionic gel (volume converted based on the density and mass of the ionic liquid) is 1~4 mol / L; the amount of organic additive added is 0.6~5 wt% of the total mass of the additive, ionic liquid, and polymer substrate.

[0012] The preparation method of the above-mentioned high-pressure ionogel electrolyte includes the following steps: (1) Dissolve the polymer substrate in acetone to obtain a polymer precursor solution; (2) Add organic additives to the polymer precursor solution obtained in step (1) to obtain a mixed precursor solution; (3) Add the ionic liquid and inorganic salt to the mixed precursor solution obtained in step (2), and after dispersing evenly, obtain the high-voltage ion gel precursor solution for sodium ion batteries. (4) Pour the sodium-ion battery high-voltage ion gel precursor solution obtained in step (3) onto a smooth glass plate and scrape it with a scraper to form a thin film ion gel electrolyte. After drying, a solid sodium-ion battery high-voltage ion gel electrolyte is obtained.

[0013] Furthermore, in step (4), the height of the scraper coating is 350-450 μm; the drying is done in a vacuum oven for 18-30 hours.

[0014] A solid sodium-ion battery includes a positive electrode, a negative electrode, and the aforementioned high-voltage ion gel electrolyte, wherein the high-voltage ion gel electrolyte is disposed between the positive electrode and the negative electrode.

[0015] Furthermore, the positive electrode includes a positive current collector and a positive electrode membrane disposed on the positive current collector. The positive electrode membrane includes a positive active material, a positive conductive agent, and a binder. The negative electrode includes a negative current collector and a negative electrode membrane disposed on the negative current collector. The negative electrode membrane includes a negative active material and a negative conductive agent. Both the positive and negative conductive agents can be any one of acetylene black, Super P Li, or carbon nanotubes, etc., and the binder is polyvinylidene fluoride (PVDF) or carboxymethyl cellulose (CMC), etc.

[0016] The positive electrode includes a positive electrode active material; the negative electrode includes a negative electrode current collector and a negative electrode film disposed on the negative electrode current collector, the negative electrode film including a negative electrode active material, a negative electrode conductive agent and a binder.

[0017] Furthermore, the positive electrode active material of the solid sodium-ion battery includes a high-voltage positive electrode material for sodium-ion batteries, and the negative electrode active material is sodium titanium phosphate or metallic sodium.

[0018] The sulfonyl group has a stable structure and strong electron-withdrawing ability. Utilizing the inductive effect of electron-withdrawing, this effectively lowers the HOMO energy level of the system. The sulfonyl group provides two hydrogen bond acceptors, and by increasing its hydrogen bond interaction with the polymer substrate, it effectively improves the electrolyte's antioxidant capacity. Simultaneously, the sulfonyl group avoids introducing additional anionic groups into the system. The ion-dipole interaction between the sulfonyl group and the sodium salt and the polymer polar groups ensures the driving force for sodium dissociation, thus guaranteeing that the electrolyte has a high voltage window while also exhibiting good ionic conductivity and electrochemical stability. The strong antioxidant capacity of the electrolyte and the stable CEI induced at the sodium ferric sulfate cathode interface ensure long-term stable cycling of the battery at a charge cutoff voltage of 4.5V. In this invention, the sulfonyl group couples with the polymer substrate, ionic liquid, and sodium salt, without interacting with the sodium anode; a high-voltage resistant CEI is constructed, resulting in high-voltage characteristics.

[0019] The present invention has the following beneficial effects: 1. The quasi-solid-state high-voltage ion gel electrolyte of the present invention contains a sodium sulfonate derivative. On the one hand, the sulfonate group can synergistically decompose sodium salt and ionic liquid under high voltage. There is an interaction between sodium salt and ionic liquid, which optimizes the solvation layer structure, thereby transporting Na+. + It participates in interface formation, balancing the decomposition ratio of sodium salt and ionic liquid, forming a stable CEI on the surface of the sodium ferric sulfate electrode, inhibiting excessive film formation of ionic liquid and sodium salt, and reducing the impedance of the positive electrode interface; on the other hand, due to the adsorption effect of sodium sulfonate, it attracts sodium salt and promotes the dissociation of sodium salt, improving the uniformity of sodium dispersion in the ionic gel electrolyte, and has a higher adsorption strength for cations in the ionic liquid, limiting the removal of Na+. + The migration of external cations. The high-voltage mechanism of the lithium battery in this invention is the TFSI in sodium bis(trifluoromethanesulfonyl)imide. - It is determined by the combined effects of anions, ionic liquids, additives, and polymer substrates.

[0020] 2. The derivatives containing sodium sulfonate groups in this invention all possess high decomposition voltages above 5V, and excellent ionic conductivity and ion transference numbers (e.g., ...). Figure 5 , Figure 6As shown in the figure, it improves the overall ion transport kinetics of sodium-ion batteries. When matched with sodium ferric sulfate, a high-voltage cathode material, the β-naphthalenesulfonate additive achieved stable cycling for 2800 cycles at a cutoff charging voltage of 4.5V; the 2,7-naphthalenedisulfonate additive achieved stable cycling for 1000 cycles at a cutoff charging voltage of 4.5V. Therefore, it is proved that the sodium sulfonate derivative additives play an important role in the ion transport kinetics and cycle stability of sodium-ion batteries at high voltage. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 The graph shows the cycle performance test curve of the high-voltage sodium-ion battery prepared in Example 1 of this invention.

[0023] Figure 2 The graph shows the cycle performance test curve of the high-voltage sodium-ion battery prepared in Example 2 of this invention.

[0024] Figure 3 The graph shows the cycle performance test curve of the high-voltage sodium-ion battery prepared in Example 3 of this invention.

[0025] Figure 4 The graph shows the cycle performance test curve of the high-pressure sodium-ion battery prepared in Example 4 of this invention.

[0026] Figure 5 The diagram shows the decomposition voltage of the high-voltage ion gel electrolyte in Examples 1-7 of this invention.

[0027] Figure 6 The diagram shows the ionic conductivity of the high-voltage ion gel electrolyte in Examples 1-7 of this invention. Detailed Implementation

[0028] 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.

[0029] All raw materials used in the embodiments of the present invention are commercially available products.

[0030] Example 1 This embodiment describes a method for preparing a high-voltage ion gel electrolyte and a sodium-ion quasi-solid-state battery using sodium β-naphthalenesulfonate as an organic additive. The steps are as follows: (1) Preparation of quasi-solid-state high-voltage ion gel electrolyte containing sodium β-naphthalenesulfonate organic additive for sodium-ion batteries 0.45 g of PVDF-HFP (polyvinylidene fluoride-hexafluoropropylene) was dissolved in acetone to form a polymer precursor solution. 0.05 g of sodium β-naphthalenesulfonate organic additive (4.5 wt% of the total mass of the polymer matrix, ionic liquid, and additive) was added, along with 0.6 g of EmimFSI ionic liquid (1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide salt) and 0.125 g of NaTFSI sodium salt (bis(trifluoromethanesulfonyl)imide sodium salt) to obtain a modified electrolyte precursor solution. The concentration of NaTFSI was 1 mol / L (volume conversion based on ionic liquid density and mass). The modified electrolyte precursor solution was coated onto a smooth glass plate using a doctor blade to a height of 400 μm. After film formation, it was dried in a vacuum drying oven and cut into quasi-solid electrolyte membranes with a diameter of 19 mm (thickness ~85 μm). These membranes were then stored in an argon-filled glove box for later use. The decomposition voltage was 5.2 V, and the ionic conductivity was 1.2 mS / cm. -1 Gel electrolyte.

[0031] (2) Assembly of high-voltage sodium-ion batteries High-voltage sodium-ion batteries were assembled using the modified quasi-solid-state high-voltage ion gel electrolyte described above, with metallic sodium as the negative electrode, sodium iron sulfate as the positive electrode, PDVF as the binder, and Super P Li as the conductive agent, and CR2025 coin cells were assembled.

[0032] Figure 1 The graph shows the cycle performance test curve of the high-voltage sodium-ion battery prepared in Example 1 of this invention. The battery, which is matched with sodium iron sulfate as the high-voltage cathode material and sodium β-naphthalenesulfonate as the gel electrolyte, has a coulombic efficiency of 100% and has been stably cycled for 2800 cycles under the condition of a cutoff charging voltage of 4.5V; the specific capacity has decreased from the initial 80mAh / g to 60mAh / g.

[0033] Example 2 This embodiment describes a method for preparing a high-voltage ion gel electrolyte and a sodium-ion quasi-solid-state battery using sodium 2,7-naphthalenedisulfonate as an organic additive. The steps are as follows: (1) Preparation of quasi-solid-state high-voltage ion gel electrolyte containing sodium 2,7-naphthalenedisulfonate organic additive for sodium-ion batteries 0.45 g of PVDF-HFP was dissolved in acetone to form a polymer precursor solution. 0.05 g of sodium 2,7-naphthalenedisulfonate organic additive (4.5 wt% of the total mass of the polymer matrix, ionic liquid, and additive) was added, along with 0.6 g of EmimFSI ionic liquid and 0.125 g of sodium NaTFSI salt, to obtain a modified electrolyte precursor solution. The concentration of NaTFSI was 1 mol / L (volume conversion based on ionic liquid density and mass). The modified electrolyte precursor solution was coated onto a smooth glass plate using a doctor blade to a height of 400 μm. After film formation, it was dried in a vacuum drying oven and cut into quasi-solid electrolyte membranes with a diameter of 19 mm (thickness ~85 μm). These membranes were then stored in an argon-filled glove box for later use. The decomposition voltage was 5.2 V, and the ionic conductivity was 1.7 mS / cm. -1 Gel electrolyte.

[0034] (2) Assembly of high-voltage sodium-ion batteries High-voltage sodium-ion batteries were assembled using the modified quasi-solid-state high-voltage ion gel electrolyte described above, with metallic sodium as the negative electrode, sodium iron sulfate as the positive electrode, PDVF as the binder, and Super P Li as the conductive agent, and CR2025 coin cells were assembled.

[0035] Sodium 2,7-naphthalenedisulfonate additive maintained stable cycling for 1000 cycles at a cutoff charging voltage of 4.5V; the cycle performance test curve of the high-voltage sodium-ion battery is shown below. Figure 2 As shown.

[0036] Example 3 This embodiment describes a method for preparing a high-voltage ion gel electrolyte and a quasi-solid-state sodium-ion battery using sodium 2,6-naphthalenedisulfonate as an organic additive. The steps are as follows: (1) Preparation of quasi-solid-state high-voltage ion gel electrolyte containing sodium 2,6-naphthalenedisulfonate organic additive for sodium-ion batteries 0.45 g of PVDF-HFP was dissolved in acetone to form a polymer precursor solution. 0.05 g of sodium 2,6-naphthalenedisulfonate organic additive (4.5 wt% of the total mass of the polymer matrix, ionic liquid, and additive) was added, along with 0.6 g of EmimFSI ionic liquid and 0.125 g of sodium NaTFSI salt, to obtain a modified electrolyte precursor solution. The concentration of NaTFSI was 1 mol / L (volume conversion based on ionic liquid density and mass). The modified electrolyte precursor solution was coated onto a smooth glass plate using a doctor blade to a height of 400 μm. After film formation, it was dried in a vacuum drying oven and cut into quasi-solid electrolyte membranes with a diameter of 19 mm (thickness ~85 μm). These membranes were then stored in an argon-filled glove box for later use. The decomposition voltage was 5 V, and the ionic conductivity was 1.5 mS / cm.-1 Gel electrolyte.

[0037] (2) Assembly of high-voltage sodium-ion batteries High-voltage sodium-ion batteries were assembled using the modified quasi-solid-state high-voltage ion gel electrolyte described above, with metallic sodium as the negative electrode, sodium iron sulfate as the positive electrode, PDVF as the binder, and Super P Li as the conductive agent, and CR2025 coin cells were assembled.

[0038] A quasi-solid-state high-voltage ion gel electrolyte with sodium 2,6-naphthalenedisulfonate as the organic additive was used to assemble a CR2025 coin cell sodium-ion battery. Under a cutoff charging voltage of 4.5V, the battery achieved stable cycling for 330 cycles. The cycle performance test curve of the high-voltage sodium-ion battery is shown in the figure below. Figure 3 As shown.

[0039] Example 4 This embodiment describes a method for preparing a high-voltage ion gel electrolyte and a quasi-solid-state sodium-ion battery using sodium 1,5-naphthalenedisulfonate as an organic additive. The steps are as follows: (1) Preparation of quasi-solid-state high-voltage ion gel electrolyte containing sodium 1,5-naphthalenedisulfonate organic additive for sodium-ion batteries 0.45 g of PVDF-HFP was dissolved in acetone to form a polymer precursor solution. 0.05 g of sodium 1,5-naphthalenedisulfonate organic additive (4.5 wt% of the total mass of the polymer matrix, ionic liquid, and additive) was added, along with 0.6 g of EmimFSI ionic liquid and 0.125 g of sodium NaTFSI salt, to obtain a modified electrolyte precursor solution. The concentration of NaTFSI was 1 mol / L (volume conversion based on ionic liquid density and mass). The modified electrolyte precursor solution was coated onto a smooth glass plate using a doctor blade to a height of 400 μm. After film formation, it was dried in a vacuum drying oven and cut into quasi-solid electrolyte membranes with a diameter of 19 mm (thickness ~85 μm). These membranes were then stored in an argon-filled glove box for later use. The decomposition voltage was 5.2 V, and the ionic conductivity was 1.24 mS / cm. -1 Gel electrolyte.

[0040] (2) Assembly of high-voltage sodium-ion batteries High-voltage sodium-ion batteries were assembled using the modified quasi-solid-state high-voltage ion gel electrolyte described above, with metallic sodium as the negative electrode, sodium iron sulfate as the positive electrode, PDVF as the binder, and Super P Li as the conductive agent, and CR2025 coin cells were assembled.

[0041] A quasi-solid-state high-voltage ion gel electrolyte with sodium 1,5-naphthalenedisulfonate as the organic additive was used to assemble a CR2025 coin cell, which maintained stable cycling for 330 cycles at a cutoff charging voltage of 4.5V. The cycle performance test curve of the high-voltage sodium-ion battery is shown in the figure below. Figure 4 As shown.

[0042] Example 5 This embodiment describes a method for preparing an ion-gel electrolyte using sodium 1,3,6-naphthalenetrisulfonate as an organic additive. The steps are as follows: 0.45 g of PVDF-HFP was dissolved in acetone to form a polymer precursor solution. 0.05 g of sodium 1,3,6-naphthalenetrisulfonate organic additive (4.5 wt% of the total mass of the polymer matrix, ionic liquid, and additive) was added, along with 0.6 g of EmimFSI ionic liquid and 0.125 g of sodium NaTFSI, to obtain a modified electrolyte precursor solution. The concentration of NaTFSI was 1 mol / L (volume conversion based on ionic liquid density and mass). The modified electrolyte precursor solution was coated onto a smooth glass plate using a doctor blade to a height of 400 μm. After film formation, it was dried in a vacuum drying oven at room temperature for 20 h. The resulting quasi-solid electrolyte membranes (~85 μm thick) with a diameter of 19 mm were cut and stored in an argon-filled glove box for later use. The decomposition voltage was 5.2 V, and the ionic conductivity was 1.23 mS / cm. -1 Gel electrolyte.

[0043] Example 6 This embodiment describes a method for preparing an ion-gel electrolyte using sodium methanesulfonate as an organic additive. The steps are as follows: 0.45 g of PVDF-HFP was dissolved in acetone to form a polymer precursor solution. 0.05 g of sodium methanesulfonate organic additive (4.5 wt% of the total mass of the polymer matrix, ionic liquid, and additive) was added, along with 0.6 g of EmimFSI ionic liquid and 0.125 g of NaTFSI sodium salt, to obtain a modified electrolyte precursor solution. The concentration of NaTFSI was 1 mol / L (volume conversion based on ionic liquid density and mass). The modified electrolyte precursor solution was coated onto a smooth glass plate using a doctor blade to a height of 450 μm. After film formation, it was dried in a vacuum drying oven at room temperature for 20 h. The resulting quasi-solid electrolyte membranes (~85 μm thick) with a diameter of 19 mm were cut and stored in an argon-filled glove box for later use. The decomposition voltage was 5.2 V, and the ionic conductivity was 1.33 mS / cm. -1 Gel electrolyte.

[0044] Example 7 This embodiment describes a method for preparing an ion-gel electrolyte using sodium benzenesulfonate as an organic additive. The steps are as follows: 0.45 g of PVDF-HFP was dissolved in acetone to form a polymer precursor solution. 0.05 g of sodium benzenesulfonate organic additive (4.5 wt% of the total mass of the polymer matrix, ionic liquid, and additive) was added, along with 0.6 g of EmimFSI ionic liquid and 0.125 g of NaTFSI sodium salt, to obtain a modified electrolyte precursor solution. The concentration of NaTFSI was 1 mol / L (volume conversion based on ionic liquid density and mass). The modified electrolyte precursor solution was coated onto a smooth glass plate using a doctor blade to a height of 350 μm. After film formation, it was dried in a vacuum drying oven at room temperature for 20 h. The resulting quasi-solid electrolyte membranes (~85 μm thick) with a diameter of 19 mm were cut and stored in an argon-filled glove box for later use. The decomposition voltage was 5.2 V, and the ionic conductivity was 1.3 mS / cm. -1 Gel electrolyte.

[0045] The derivatives containing sodium sulfonate groups in this invention all possess high decomposition voltages above 5V, and excellent ionic conductivity and ion transference numbers (e.g., ...). Figure 5 , Figure 6 As shown in the figure, the overall ion transport kinetics of the sodium-ion battery are improved. When matched with sodium iron sulfate, a high-voltage cathode material, the prepared high-voltage battery has high specific capacity and cycle stability under a charging voltage of 4.5V.

[0046] Example 8 This embodiment describes a method for preparing an ion-gel electrolyte using sodium vinyl sulfonate as an organic additive. The steps are as follows: 0.45 g of PVDF-HFP was dissolved in acetone to form a polymer precursor solution. 0.05 g of sodium vinyl sulfonate organic additive (0.63 wt% of the total mass of the polymer matrix, ionic liquid, and additive) was added, along with 0.6 g of EmimFSI ionic liquid and 0.125 g of NaTFSI sodium salt, to obtain a modified electrolyte precursor solution. The concentration of NaTFSI was 1 mol / L (volume conversion based on ionic liquid density and mass). The modified electrolyte precursor solution was coated onto a smooth glass plate using a doctor blade to a height of 350 μm. After film formation, it was dried in a vacuum drying oven at room temperature for 18 h. The resulting quasi-solid electrolyte membranes (~85 μm thick) with a diameter of 19 mm were cut and stored in an argon-filled glove box for later use.

[0047] Example 9 This embodiment describes a method for preparing an ion-gel electrolyte using sodium aminosulfonate as an organic additive. The steps are as follows: 0.45 g of PVDF-HFP was dissolved in acetone to form a polymer precursor solution. 0.05 g of sodium aminosulfonate organic additive (5 wt% of the total mass of the polymer matrix, ionic liquid, and additive) was added, along with 0.6 g of EmimFSI ionic liquid and 0.125 g of NaTFSI sodium salt, to obtain a modified electrolyte precursor solution. The concentration of NaTFSI was 1 mol / L (volume conversion based on ionic liquid density and mass). The modified electrolyte precursor solution was coated onto a smooth glass plate using a doctor blade to a height of 350 μm. After film formation, it was dried at room temperature in a vacuum drying oven for 30 h. The resulting quasi-solid electrolyte membranes (~85 μm thick) with a diameter of 19 mm were cut and stored in an argon-filled glove box for later use.

[0048] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-voltage ionic gel electrolyte, characterized by: The basic ionic gel comprises inorganic salt, polymer base and ionic liquid, and an organic additive, wherein the organic additive is sodium sulfonate derivative.

2. The high pressure ionic gel electrolyte of claim 1, wherein: The sodium sulfonate derivative has a general structure of R-SO3Na, wherein the number of -SO3Na groups is at least one, and R is alkyl, amino or aryl.

3. The high pressure ionic gel electrolyte of claim 2, wherein, The alkyl is -CH3, -CH=CH2, the amino is -NH2, and the aryl structure is any of the foregoing.

4. The high pressure ionic gel electrolyte of claim 1, wherein, The inorganic salt is sodium bis(trifluoromethylsulfonyl)imide, the polymer base is polyvinylidene hexafluoropropylene, and the ionic liquid is 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide.

5. The high pressure ionic gel electrolyte of claim 1, wherein, The mass ratio of the sum of the mass of the polymer base and the organic additive to the mass of the ionic liquid and the inorganic salt is 0.5:0.6:(0.117-0.5), wherein the concentration of the inorganic salt in the basic ionic gel is 1-4 mol / L, and the addition amount of the organic additive is 0.6-5 wt% of the total mass of the additive, the polymer base and the ionic liquid.

6. Process for the preparation of a high-pressure ionic gel electrolyte according to any one of claims 1 to 5, characterized in that, The method comprises the following steps: (1) dissolving the polymer base in acetone to obtain a polymer precursor solution, and mixing the polymer precursor solution with the organic additive to obtain a mixed precursor solution; (2) further mixing and uniformly dispersing the ionic liquid, the inorganic salt and the mixed precursor solution to obtain a sodium ion battery high-voltage ionic gel precursor solution; (4) pouring the sodium ion battery high-voltage ionic gel precursor solution obtained in step (3) onto a smooth glass plate and scraping it with a doctor blade to form a thin film-shaped ionic gel electrolyte, and drying to obtain a solid-state sodium ion battery high-voltage ionic gel electrolyte.

7. The method of claim 6, wherein the high-voltage ionic gel electrolyte is prepared by adding the electrolyte solution to the polymer solution, and then stirring the mixture at a temperature of 20 to 30°C for 1 to 3 hours. The scraping height of the doctor blade in step (4) is 350-450 μm, and the drying is vacuum oven drying, and the drying time is 18-30 h.

8. A solid-state sodium-ion battery comprising a positive electrode, a negative electrode, and an electrolyte, characterized in that, The electrolyte is the high-voltage ionic gel electrolyte according to any one of claims 1-5.

9. The solid-state sodium-ion battery of claim 8, wherein, The positive electrode comprises a positive electrode current collector and a positive electrode membrane arranged on the positive electrode current collector, and the positive electrode membrane comprises positive electrode active material, positive electrode conductive agent and binder; the negative electrode comprises a negative electrode current collector and a negative electrode membrane arranged on the negative electrode current collector, and the negative electrode membrane comprises negative electrode active material and negative electrode conductive agent; the positive electrode conductive agent and the negative electrode conductive agent can be acetylene black, Super P Li or carbon nanotube, and the binder is polyvinylidene fluoride or hydroxymethyl cellulose.

10. The solid-state sodium-ion battery of claim 8, wherein, The positive electrode active material of the solid-state sodium ion battery comprises a high-voltage positive electrode material for sodium ion battery, and the negative electrode active material is sodium titanium phosphate or metallic sodium.

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