Quasi-solid sodium electroelectrolyte as well as preparation method and application thereof

Abstract

The invention discloses a quasi-solid sodium electroelectrolyte and a preparation method and application thereof, and belongs to the technical field of sodium metal batteries. The quasi-solid sodium electric electrolyte provided by the invention comprises a light curing agent, a sodium ion electrolyte and a two-dimensional material, the two-dimensional material comprises one or more of fluorinated graphene, titanium nitride, boron nitride, silicon disulfide, tungsten disulfide and silicon carbide. The quasi-solid-state sodium electric electrolyte provided by the invention has good mechanical strength and mechanical stability, the resistance of the quasi-solid-state sodium electric electrolyte can be reduced, and the ionic conductivity is improved; when the quasi-solid sodium electroelectrolyte is applied to a sodium metal battery, the sodium metal battery has relatively high specific capacity under both low multiplying power and high multiplying power, and long-time cycling stability can be maintained.

Description

Technical Field

[0001] The present application belongs to the technical field of sodium metal batteries, and in particular relates to a quasi-solid-state sodium electrolyte and a preparation method and application thereof. Background Art

[0002] Solid electrolytes can solve the safety issues of traditional organic liquid electrolytes. However, their low ionic conductivity and large interface resistance limit their practical applications. Therefore, improving the ionic conductivity of solid electrolytes and reducing the interface resistance become the key to developing high-performance sodium metal batteries.

[0003] At present, there are literature reports on the design and preparation of quasi-solid-state electrolytes. For example, Wen Pengchao et al. (Adv. Energy Mater. 2021, 11, 2002930) successfully prepared a photopolymerized gel electrolyte with high room temperature ionic conductivity, which is suitable for high energy density solid-state sodium metal batteries. However, its specific capacity at high rates is relatively low. Wei Ling et al. (Adv. Energy Mater. 2020, 10, 1903966) successfully prepared a multilayer flexible solid electrolyte for sodium metal batteries. The flexible solid electrolyte with a multilayer structure shows great advantages in solving the problems of ionic conductivity and interface resistance. However, the sodium metal solid-state battery composed of this cannot maintain long-term cycle stability. Summary of the invention

[0004] In order to solve the above technical problems, the present application provides a quasi-solid-state sodium electrolyte and a preparation method and application thereof. The quasi-solid-state sodium electrolyte has good mechanical strength and mechanical stability, can reduce the resistance of the quasi-solid-state sodium electrolyte, and improve the ionic conductivity; when the quasi-solid-state sodium electrolyte is applied to a sodium metal battery, it has a higher specific capacity at both low and high rates, and can maintain long-term cycle stability.

[0005] In order to achieve the above-mentioned invention object, this application provides the following technical solutions:

[0006] On the one hand, the present application provides a quasi-solid sodium electrolyte, wherein the quasi-solid sodium electrolyte comprises a photocuring agent, a sodium ion electrolyte and a two-dimensional material;

[0007] The two-dimensional material includes one or more of fluorinated graphene, titanium nitride, boron nitride, silicon disulfide, tungsten disulfide and silicon carbide.

[0008] Optionally, the volume proportion of the two-dimensional material in the quasi-solid sodium electrolyte is 0.1-20%.

[0009] Optionally, the sodium ion electrolyte includes sodium perchlorate, propylene carbonate and fluoroethylene carbonate.

[0010] Optionally, the volume ratio of the sodium ion electrolyte to the photocuring agent is 3 to 5:1, wherein the volume of the sodium ion electrolyte is calculated based on the volume of the substance itself, and the volume of the photocuring agent is calculated based on the volume of the substance itself.

[0011] Optionally, the mass ratio of the two-dimensional material to the photocuring agent is 0.1-20%, wherein the mass of the two-dimensional material is calculated based on the mass of the material itself, and the mass of the photocuring agent is calculated based on the mass of the material itself.

[0012] In a second aspect, the present application provides a method for preparing the above-mentioned quasi-solid-state sodium electrolyte, comprising the following steps:

[0013] The photocuring agent, sodium ion electrolyte and two-dimensional material are mixed and cured to obtain the quasi-solid sodium electrolyte.

[0014] Optionally, the volume proportion of the two-dimensional material in the quasi-solid sodium electrolyte is 0.1-20%.

[0015] Optionally, the volume ratio of the sodium ion electrolyte to the photocuring agent is 3 to 5:1, wherein the volume of the sodium ion electrolyte is calculated based on the volume of the substance itself, and the volume of the photocuring agent is calculated based on the volume of the substance itself.

[0016] Optionally, the mass ratio of the two-dimensional material to the photocuring agent is 0.1-20%, wherein the mass of the two-dimensional material is calculated based on the mass of the material itself, and the mass of the photocuring agent is calculated based on the mass of the material itself.

[0017] Optionally, the photocuring agent includes a photocuring monomer and a photoinitiator.

[0018] Optionally, the mass ratio of the photocurable monomer to the photoinitiator is 90 to 110:1, wherein the mass of the photocurable monomer is calculated based on the mass of the substance itself, and the mass of the photoinitiator is calculated based on the mass of the substance itself.

[0019] Optionally, the photocurable monomer includes ethoxylated trimethylolpropane triacrylate;

[0020] The photoinitiator includes 2-hydroxy-2-methylpropiophenone.

[0021] Optionally, the sodium ion electrolyte includes sodium perchlorate, propylene carbonate and fluoroethylene carbonate.

[0022] Optionally, the two-dimensional material includes one or more of fluorinated graphene, titanium nitride, boron nitride, silicon disulfide, tungsten disulfide and silicon carbide.

[0023] Optionally, the mass ratio of the sodium perchlorate, propylene carbonate and fluoroethylene carbonate is 50-100:1-5:1-5.

[0024] Optionally, the molar concentration of propylene carbonate is 0.0001 to 0.0005 mol / L;

[0025] The molar concentration of the fluoroethylene carbonate is 0.0001-0.0005 mol / L.

[0026] Optionally, the curing is performed using an ultraviolet lamp.

[0027] Optionally, the wavelength of the ultraviolet lamp is 350-450nm.

[0028] Optionally, the curing time is 20 to 60 seconds.

[0029] In a third aspect, the present application provides the application of the above-mentioned quasi-solid-state sodium electrolyte in the preparation of sodium metal batteries.

[0030] Compared with the prior art, this application has the following beneficial effects:

[0031] (1) The quasi-solid sodium electrolyte provided in the present application has good mechanical strength and mechanical stability, which can reduce the resistance of the quasi-solid sodium electrolyte and improve the ionic conductivity.

[0032] (2) The quasi-solid-state sodium electrolyte prepared by the preparation method provided in this application has high quality, good performance and a wide range of applications.

[0033] (3) The quasi-solid-state sodium electrolyte provided in the present application is applied to sodium metal batteries, which have a high specific capacity at both low and high rates and can maintain long-term cycle stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 EIS test performed on the quasi-solid-state sodium electrolyte prepared in Example 1 of the present application;

[0035] Figure 2 Ionic conductivity test of the quasi-solid sodium electrolyte prepared in Example 1 of the present application;

[0036] Figure 3 The constant current charge and discharge curve of the quasi-solid-state sodium electrolyte prepared in Example 1 of the present application in a sodium metal battery;

[0037] Figure 4 This is the plating / stripping curve of the quasi-solid-state sodium electrolyte prepared in Example 1 of the present application in a sodium-sodium symmetric battery. DETAILED DESCRIPTION

[0038] The present application is further described below in conjunction with specific embodiments. The following are only a few embodiments of the present application, and are not intended to limit the present application in any form. Although the present application discloses the following preferred embodiments, they are not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the above disclosed technical content to make some changes or modifications are equivalent to equivalent implementation cases and are within the scope of the technical solution.

[0039] Unless otherwise specified, the raw materials in the examples of the present application were purchased from commercial sources and used directly without any special treatment.

[0040] Unless otherwise specified, the analysis methods in the examples all adopt conventional settings and conventional analysis methods of instruments or equipment.

[0041] In the following examples, ETPTA is a photocurable monomer, ethoxylated trimethylolpropane triacrylate, and HMPP is a photoinitiator, 2-hydroxy-2-methylpropiophenone. + The electrolyte is 1.0 M NaClO 4 dissolved in propylene carbonate (PC) and 5% fluoroethylene carbonate (FEC) solution, and the mass ratio of NaClO 4 , propylene carbonate (PC) and fluoroethylene carbonate is 100:5:5.

[0042] Example 1

[0043] A method for preparing a quasi-solid sodium electrolyte, comprising the following steps:

[0044] Different contents of two-dimensional material boron nitride (the mass ratio of boron nitride to photocuring agent was 0%, 1%, 2.5%, and 5%) were taken, mixed with 200 μL photocuring agent (ETPTA:HMPP=100:1) and 800 μL Na + The electrolyte was mixed and shaken evenly, and a quasi-solid sodium electrolyte was obtained after curing with 395 nm ultraviolet light for 30 seconds.

[0045] Example 2

[0046] A method for preparing a quasi-solid sodium electrolyte, comprising the following steps:

[0047] Different contents of two-dimensional material silicon carbide (the mass ratio of boron nitride to photocuring agent was 0%, 1%, 2.5%, and 5%, respectively) were taken, mixed with 200 μL photocuring agent (ETPTA:HMPP=100:1) and 800 μL Na + The electrolyte was mixed and shaken evenly, and a quasi-solid sodium electrolyte was obtained after curing with 395 nm ultraviolet light for 30 seconds.

[0048] Example 3

[0049] A method for preparing a quasi-solid sodium electrolyte, comprising the following steps:

[0050] Different contents of two-dimensional material titanium nitride (the mass ratio of boron nitride to photocuring agent was 0%, 1%, 2.5%, and 5%, respectively) were taken, mixed with 200 μL photocuring agent (ETPTA:HMPP=100:1) and 800 μL Na + The electrolyte was mixed and shaken evenly, and a quasi-solid sodium electrolyte was obtained after curing with 395 nm ultraviolet light for 30 seconds.

[0051] Example 4

[0052] A method for preparing a quasi-solid sodium electrolyte, comprising the following steps:

[0053] Different contents of two-dimensional material silicon disulfide (the mass ratio of boron nitride to photocuring agent was 0%, 1%, 2.5%, and 5%, respectively) were taken, mixed with 200 μL photocuring agent (ETPTA:HMPP=100:1) and 800 μL Na + The electrolyte was mixed and shaken evenly, and a quasi-solid sodium electrolyte was obtained after curing with 395 nm ultraviolet light for 30 seconds.

[0054] Experimental Example 1

[0055] The quasi-solid sodium electrolytes prepared in Examples 1 to 4 were subjected to electrochemical tests, and the test methods included EIS test, constant current charge-discharge test, and Na-Na symmetric cell plating / stripping test. The EIS test and constant current charge-discharge test were performed using a Chenhua 760E electrochemical workstation.

[0056] Typical test results are as follows: Figure 1 As shown, this corresponds to the quasi-solid-state sodium electrolyte prepared in Example 1. Figure 1 It is shown that the resistance of the quasi-solid-state sodium electrolyte decreases after adding the two-dimensional material BN.

[0057] Typical test results are as follows: Figure 2 As shown, this corresponds to the quasi-solid-state sodium electrolyte prepared in Example 1. Figure 2 It is shown that the ionic conductivity of the quasi-solid-state sodium electrolyte increases after the addition of the two-dimensional material BN.

[0058] Typical test results are as follows: Figure 3 As shown, this corresponds to the quasi-solid-state sodium electrolyte prepared in Example 1. Figure 3 It shows that after adding BN (taking Example 1 in which 1% of the two-dimensional material boron nitride is added as an example), the sodium metal battery has a higher specific capacity at a high rate.

[0059] Typical test results are as follows: Figure 4As shown, the test results of the quasi-solid-state sodium electrolyte prepared in Example 1 (taking Example 1 with 1% of two-dimensional material boron nitride added as an example) in the electroplating and stripping processes of the Na-Na symmetric battery show that the electrolyte has good applicability in the sodium-sodium symmetric battery.

[0060] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A quasi-solid sodium electrolyte, characterized in that: The quasi-solid sodium electrolyte comprises a photocuring agent, a sodium ion electrolyte and a two-dimensional material; The two-dimensional material includes one or more of fluorinated graphene, titanium nitride, boron nitride, silicon disulfide, tungsten disulfide and silicon carbide.

2. A quasi-solid sodium electrolyte according to claim 1, characterized in that: The volume proportion of the two-dimensional material in the quasi-solid sodium electrolyte is 0.1-20%.

3. A quasi-solid sodium electrolyte according to claim 1, characterized in that: The sodium ion electrolyte comprises sodium perchlorate, propylene carbonate and fluoroethylene carbonate; Preferably, the volume ratio of the sodium ion electrolyte to the photocuring agent is 3 to 5:1, wherein the volume of the sodium ion electrolyte is calculated based on the volume of the substance itself, and the volume of the photocuring agent is calculated based on the volume of the substance itself; Preferably, the mass ratio of the two-dimensional material to the photocuring agent is 0.1-20%, wherein the mass of the two-dimensional material is calculated based on the mass of the material itself, and the mass of the photocuring agent is calculated based on the mass of the material itself.

4. The method for preparing the quasi-solid sodium electrolyte according to any one of claims 1 to 3, characterized in that: The steps include: The photocuring agent, sodium ion electrolyte and two-dimensional material are mixed and cured to obtain the quasi-solid sodium electrolyte.

5. The method for preparing a quasi-solid sodium electrolyte according to claim 4, characterized in that: The volume proportion of the two-dimensional material in the quasi-solid sodium electrolyte is 0.1 to 20%; Preferably, the volume ratio of the sodium ion electrolyte to the photocuring agent is 3 to 5:1, wherein the volume of the sodium ion electrolyte is calculated based on the volume of the substance itself, and the volume of the photocuring agent is calculated based on the volume of the substance itself; Preferably, the mass ratio of the two-dimensional material to the photocuring agent is 0.1-20%, wherein the mass of the two-dimensional material is calculated based on the mass of the material itself, and the mass of the photocuring agent is calculated based on the mass of the material itself.

6. The method for preparing the quasi-solid sodium electrolyte according to claim 4, characterized in that: The photocuring agent includes a photocuring monomer and a photoinitiator; Preferably, the mass ratio of the photocurable monomer to the photoinitiator is 90 to 110:1, wherein the mass of the photocurable monomer is calculated based on the mass of the substance itself, and the mass of the photoinitiator is calculated based on the mass of the substance itself; Preferably, the photocurable monomer comprises ethoxylated trimethylolpropane triacrylate; The photoinitiator includes 2-hydroxy-2-methylpropiophenone.

7. The method for preparing the quasi-solid sodium electrolyte according to claim 4, characterized in that: The sodium ion electrolyte comprises sodium perchlorate, propylene carbonate and fluoroethylene carbonate; Preferably, the two-dimensional material includes one or more of fluorinated graphene, titanium nitride, boron nitride, silicon disulfide, tungsten disulfide and silicon carbide.

8. The method for preparing the quasi-solid sodium electrolyte according to claim 7, characterized in that: The mass ratio of the sodium perchlorate, propylene carbonate and fluoroethylene carbonate is 50-100:1-5:1-5; Preferably, the molar concentration of propylene carbonate is 0.0001 to 0.0005 mol / L; The molar concentration of the fluoroethylene carbonate is 0.0001-0.0005 mol / L.

9. The method for preparing a quasi-solid sodium electrolyte according to claim 4, characterized in that: The curing is carried out using an ultraviolet lamp; Preferably, the wavelength of the ultraviolet lamp is 350-450nm; Preferably, the curing time is 20 to 60 seconds.

10. Use of the quasi-solid sodium electrolyte according to any one of claims 1 to 3 or the quasi-solid sodium electrolyte prepared by the preparation method according to any one of claims 4 to 9 in the preparation of sodium metal batteries.

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