Artificial solid electrolyte interface film, preparation method thereof and sodium ion battery containing artificial solid electrolyte interface film

Abstract

The invention belongs to the technical field of batteries, and relates to an artificial solid electrolyte interface film, a preparation method thereof and a sodium ion battery containing the same. The artificial solid electrolyte interface film contains sodium-modified naphthol and a giant dielectric ceramic powder material, and the mass ratio of the sodium-modified naphthol to the giant dielectric ceramic powder material is 1: (1-19). The artificial solid electrolyte interface film has good sodium ion conductivity, electronic insulativity and mechanical strength, and can guarantee rapid and efficient ion transport and balance of interface sodium ion beams in a sodium ion battery negative electrode containing the artificial solid electrolyte interface film.

Description

Technical Field

[0001] The invention belongs to the technical field of batteries and relates to an artificial solid electrolyte interface membrane, a preparation method thereof and a sodium ion battery containing the same. Background Art

[0002] Lithium-ion batteries are currently the most commonly used batteries, but the global shortage of lithium resources has limited their future development. However, due to the abundant reserves of sodium on Earth, sodium-ion batteries (SIBs) have the potential to replace lithium-ion batteries in some areas.

[0003] In sodium-ion batteries, metallic sodium is an ideal negative electrode material for constructing high-energy sodium-ion battery systems due to its extremely high theoretical specific capacity and relatively negative electrochemical potential. However, when metallic sodium is used as the negative electrode of sodium-ion batteries, the safe use of sodium-ion batteries faces huge challenges. The main reason is that the highly active metallic sodium negative electrode reacts with the electrolyte to form a solid electrolyte interface membrane (SEI), which causes a series of problems such as electrolyte consumption and reduced battery coulombic efficiency. In addition, the loose and fragile surface SEI cannot cope with the interfacial stress during the cycling process of sodium-ion batteries. The repeated fracture / repair of the SEI will directly cause the generation of a large number of dendrites and dead sodium. Therefore, constructing a functionalized artificial SEI interface layer on the surface of the metallic sodium negative electrode of sodium-ion batteries, so that it has good sodium ion conductivity, electronic insulation and mechanical strength, and ensures fast and efficient ion transport and balanced interfacial sodium ion beam flow, has become an effective strategy to address the above challenges. Summary of the Invention

[0004] The primary purpose of the present invention is to provide an artificial solid electrolyte interface membrane that has good sodium ion conductivity, electronic insulation and mechanical strength, and ensures rapid and efficient ion transport and balanced interfacial sodium ion beam flow in the negative electrode of a sodium ion battery containing the membrane.

[0005] To achieve this object, in a basic embodiment, the present invention provides an artificial solid electrolyte interface membrane, which contains sodium naphthol and giant dielectric ceramic powder material, and the mass ratio of the sodium naphthol to the giant dielectric ceramic powder material is 1:1-19.

[0006] The relevant principles of the present invention are as follows.

[0007] Nafion is a perfluorosulfonic acid polymer. Its perfluorosulfonic acid skeleton can provide good structural support, while its interior is only composed of sulfonic acid groups (SO 3-) can move freely, so it has single ion transport properties. Based on this property, naphthol is often used as a proton exchange membrane. Sodiumization of naphthol solution can replace the free hydrogen ions on its sulfonic acid group with sodium ions to obtain sodium naphthol. The sodiumized naphthol solution has a higher ionic conductivity (about 5×10 -4 At the same time, naphthol, as a polymer, has excellent film-forming properties and can form a flexible and dense naphthol film with excellent mechanical strength (180 MPa).

[0008] In addition, the uneven and uneven surface of the sodium metal negative electrode in sodium-ion batteries leads to a large local electric field gradient on the sodium metal surface, resulting in an uneven electric field. This is also the driving force behind the uncontrollable growth of tree-like and mossy sodium dendrites. Therefore, a uniform electric field at the negative electrode interface of sodium-ion batteries is one of the necessary conditions for uniform sodium ion deposition, which is particularly important at higher current densities.

[0009] Utilizing the intrinsic properties of the interfacial layer to regulate the electric field within a sodium-ion battery not only allows for a more direct effect on the sodium deposition interface but also remains unaffected by the external environment, making it more practical. Dielectric materials are materials in which, under the action of an external electric field, the centers of gravity of the positive and negative bound charges within the material do not coincide, resulting in charge migration or dipole orientation, and an internal reverse polarization electric field is generated. The dielectric constant ε is an intrinsic physical quantity that characterizes the polarization ability of a dielectric material and is proportional to its responsiveness to an external electric field. Conventional sodium-ion electrolytes and polymers have relatively low dielectric constants (5-80 and 3-50, respectively), and their impact on the electric field distribution is relatively limited. Giant dielectric ceramics (dielectric constant ≥1000), such as BaTiO3, have extremely high dielectric constants and can provide rapid and substantial feedback to micro-area electric field changes even with minimal use. Reverse polarization can be used to achieve a balanced interfacial electric field and uniform sodium ion flux, fundamentally suppressing sodium dendrites without compromising interface stability or battery energy density.

[0010] In a preferred embodiment, the present invention provides an artificial solid electrolyte interface membrane, wherein the giant dielectric ceramic powder material is selected from barium titanate and / or lead zirconate titanate.

[0011] A second object of the present invention is to provide a method for preparing the artificial solid electrolyte interface membrane as described above, so as to better prepare the artificial solid electrolyte interface membrane as described above, so that the artificial solid electrolyte interface membrane can have good sodium ion conductivity, electronic insulation and mechanical strength, and ensure rapid and efficient ion transport and balanced interfacial sodium ion beam flow in the negative electrode of the sodium ion battery containing it.

[0012] To achieve this object, in a basic embodiment, the present invention provides a method for preparing the artificial solid electrolyte interface membrane as described above, the preparation method comprising the following steps:

[0013] (1) preparing the sodium naphthol;

[0014] (2) Adding the giant dielectric ceramic powder material to the organic solvent solution of sodium naphthol, fully dispersing the powder to obtain an organic solvent dispersion of an artificial solid electrolyte interface membrane, and drying the dispersion to obtain the artificial solid electrolyte interface membrane.

[0015] In a preferred embodiment, the present invention provides a method for preparing the artificial solid electrolyte interface membrane as described above, wherein in step (1), the naphthol aqueous solution is titrated with sodium hydroxide solution to a pH of 6.5-7.5, and the sodium naphthol is obtained after drying.

[0016] In a preferred embodiment, the present invention provides a method for preparing the artificial solid electrolyte interface membrane as described above, wherein in step (2), the organic solvent is selected from dimethyl sulfoxide and / or tetrahydrofuran.

[0017] In a preferred embodiment, the present invention provides a method for preparing the artificial solid electrolyte interface membrane as described above, wherein in step (2), the mass percentage concentration of the organic solvent solution of sodium naphthol is 2-20%.

[0018] In a preferred embodiment, the present invention provides a method for preparing the artificial solid electrolyte interface membrane as described above, wherein in step (2), the mass percentage content of the giant dielectric ceramic powder material in the organic solvent dispersion of the artificial solid electrolyte interface membrane is 0.5-95%.

[0019] A third object of the present invention is to provide a sodium ion battery negative electrode that can ensure rapid and efficient ion transport and balanced interfacial sodium ion beam flow.

[0020] To achieve this objective, in a basic embodiment, the present invention provides a sodium ion battery anode, wherein the sodium ion battery anode is coated with the artificial solid electrolyte interface membrane described above on the surface of a sodium metal sheet. Preferably, the artificial solid electrolyte interface membrane has a thickness of 10-1000 nm.

[0021] A fourth object of the present invention is to provide a method for preparing a sodium ion battery negative electrode as described above, so as to better prepare the sodium ion battery negative electrode as described above, and the prepared sodium ion battery negative electrode can ensure rapid and efficient ion transport and balanced interface sodium ion beam flow therein.

[0022] To achieve this object, in a basic embodiment, the present invention provides a method for preparing a negative electrode for a sodium ion battery as described above, wherein the preparation method comprises adding an organic solvent dispersion of the artificial solid electrolyte interface membrane as described above to the surface of a sodium metal sheet, and obtaining the negative electrode for the sodium ion battery after drying.

[0023] A fifth object of the present invention is to provide a sodium ion battery that can ensure rapid and efficient ion transport and balanced interface sodium ion beam flow.

[0024] To achieve this object, in a basic embodiment, the present invention provides a sodium ion battery, which comprises the sodium ion battery negative electrode as described above.

[0025] The beneficial effects of the present invention are that the artificial solid electrolyte interface membrane of the present invention has good sodium ion conductivity, electronic insulation and mechanical strength, and can ensure rapid and efficient ion transport and balanced interface sodium ion beam flow in the negative electrode of the sodium ion battery containing it.

[0026] The present invention constructs a functionalized artificial solid electrolyte interface membrane, utilizing single-ion conduction and high-ionic conductivity sodium-naphthol to achieve a stable SEI interface and efficient sodium ion transport; utilizing a trace amount of giant dielectric ceramic (BaTiO3) to dynamically control the interfacial electric field to achieve a balanced interfacial electric field and a uniform sodium ion beam, thereby suppressing sodium dendrites from the source; and the composite of organic sodium-naphthol and inorganic giant dielectric ceramic improves the stability of the artificial solid electrolyte interface membrane while synergistically enhancing the single, rapid sodium ion transport characteristics (compared to the sodium-naphthol alone, the composite membrane formed after the giant dielectric ceramic is added has significantly improved ionic conductivity and ion migration number). Thus, the present invention realizes the application of a single-ion artificial interface layer with an electric field balancing mechanism in the construction of a highly stable sodium metal negative electrode.

[0027] The beneficial effects of the present invention are specifically embodied in:

[0028] (1) The sodium-containing naphthol in the artificial solid electrolyte interface membrane of the present invention can enable the artificial solid electrolyte interface membrane to achieve single ion conduction, high ion conductivity, stable and efficient sodium ion transport.

[0029] (2) The trace amount of giant dielectric ceramic (barium titanate) in the artificial solid electrolyte interface membrane of the present invention enables the artificial solid electrolyte interface membrane to achieve dynamic regulation of the interface electric field, balance the interface electric field and uniform sodium ion beam flow, and suppress sodium dendrites from the root.

[0030] (3) The artificial solid electrolyte interface film of the present invention, which is a composite of organic sodium naphthol and inorganic giant dielectric ceramic, can effectively improve the mechanical properties of the composite artificial SEI, thereby improving its stability.

[0031] (4) In the artificial solid electrolyte interface film of the present invention, which is a composite of organic sodium-naphthol and inorganic giant dielectric ceramic, the sodium ion transference number of sodium-naphthol can be effectively increased due to the influence of inorganic giant dielectric ceramic barium titanate on the interface electric field.

[0032] (5) In the artificial solid electrolyte interface film of the present invention, which is a composite of organic sodium naphthol and inorganic giant dielectric ceramic, the dielectric properties of the inorganic giant dielectric ceramic barium titanate will accelerate the sodium ion transmission speed in the sodium naphthol, thereby effectively enhancing the rapid sodium ion transport characteristics in the composite artificial SEI. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is the SEM electron microscope detection result of the artificial solid electrolyte interface membrane prepared in Example 1.

[0034] Figure 2 This is the XRD test result diagram of the artificial solid electrolyte interface film prepared in Example 1.

[0035] Figure 3 This is a diagram showing the negative electrode cycle stability test results of Example 4. DETAILED DESCRIPTION

[0036] In order to better understand the technical solutions and advantages of the present invention, the present invention is further described below through embodiments and comparative examples in conjunction with the accompanying drawings.

[0037] Example 1: Preparation of a Sodium Ion Battery with an Anode Coated with an Artificial Solid Electrolyte Interface Film (I)

[0038] A sodium ion battery with an artificial solid electrolyte interface membrane coated on the negative electrode was prepared according to the following steps.

[0039] (1) Preparation of sodium naphthol

[0040] Titrate 1 wt% of naphthol aqueous solution with 1 M sodium hydroxide solution to pH = 7 (to prove that H + All have been replaced by Na + ), and then dried at 80 ° C to obtain sodium naphthol.

[0041] (2) Preparation of organic solvent dispersions of artificial solid electrolyte interface membranes

[0042] The sodium naphthol prepared in the above step (1) is dissolved in dimethyl sulfoxide (DMSO) to prepare an organic solvent solution of sodium naphthol with a mass percentage concentration of 5%, and then barium titanate powder is added, and magnetic stirring and ultrasonic dispersion are combined to obtain an organic solvent dispersion of an artificial solid electrolyte interface film, wherein the mass of barium titanate is twice the mass of sodium naphthol.

[0043] (3) Preparation of sodium ion battery negative electrode

[0044] The sodium metal sheet was placed on the base of the slurry dispersing machine, and the organic solvent dispersion of the artificial solid electrolyte interface membrane prepared in the above step (2) was spin-coated on the surface of the sodium metal sheet using a pipette (spin coating speed 6000 r / min, spin coating 60 s). After drying, a sodium ion battery negative electrode with an artificial solid electrolyte interface membrane (thickness 500 nm) on the surface was obtained.

[0045] (4) Preparation of sodium ion batteries

[0046] The sodium ion battery was assembled in a glove box. The atmosphere in the glove box was argon with a water and oxygen content of less than 0.01 ppm. The sodium ion battery negative electrode prepared in step (3) was used as the negative electrode, a metal copper sheet was used as the positive electrode, a glass fiber (GF / D, Whatman) was used as the separator, and 1M NaPF6 + EC-DMC (5 wt% FEC) was used as the electrolyte to assemble a CR2032 button cell.

[0047] The artificial solid electrolyte interface film on the negative electrode of the sodium ion battery prepared in step (3) was subjected to SEM electron microscopy and XRD detection (scanning range 10-70°, scanning speed 3° / min), and the results were as follows: Figure 1 and Figure 2 shown. Figure 1 The results showed that barium titanate powder particles were uniformly dispersed in sodium naphthol. Figure 2 The results showed that the artificial solid electrolyte interface membrane was composed of sodium naphthol and barium titanate powder, which indicated that an artificial solid electrolyte interface membrane composed of barium titanate uniformly dispersed in sodium naphthol was successfully prepared.

[0048] Example 2: Preparation of a Sodium Ion Battery with an Anode Coated with an Artificial Solid Electrolyte Interface Film (II)

[0049] The preparation steps of this embodiment are basically the same as those of Example 1, except that the mass ratio of sodium naphthol to barium titanate in step (2) is adjusted to 1:1.

[0050] Example 3: Preparation of a Sodium Ion Battery with an Anode Coated with an Artificial Solid Electrolyte Interface Film (III)

[0051] The preparation steps of this embodiment are basically the same as those of Example 1, except that the mass ratio of sodium naphthol to barium titanate in step (2) is adjusted to 1:19.

[0052] Comparative Example 1: Preparation of a Sodium Ion Battery Using Untreated Sodium Metal Sheets

[0053] A sodium ion battery without any treatment of sodium metal sheet was prepared by the method of step (4) of Example 1 using a sodium metal sheet without any treatment (omitting steps (1), (2) and (3) of Example 1).

[0054] Comparative Example 2: Preparation of a sodium ion battery with a sodium metal sheet coated only with sodium naphthol

[0055] (1) Preparation of sodium naphthol

[0056] The method is the same as step (1) of Example 1.

[0057] (2) Preparation of organic solvent solution of sodium naphthol

[0058] The sodium naphthol prepared in the above step (1) is dissolved in dimethyl sulfoxide (DMSO) to prepare an organic solvent solution of sodium naphthol with a mass percentage concentration of 5%.

[0059] (3) Preparation of sodium ion battery negative electrode

[0060] The sodium metal sheet was placed on the base of the spin coater, and the organic solvent solution of sodium naphthol prepared in the above step (2) was spin-coated on the surface of the sodium metal sheet using a pipette (spin coating speed 6000 r / min, spin coating 60 s). After drying, a sodium ion battery negative electrode with sodium naphthol (thickness 500 nm) on the surface was obtained.

[0061] (4) Preparation of sodium ion batteries

[0062] The method is the same as step (4) of Example 1.

[0063] Comparative Example 3: Preparation of sodium ion battery with sodium metal sheet coated with PVDF and barium titanate

[0064] (1) Preparation of organic solvent dispersion of barium titanate

[0065] PVDF was dissolved in dimethyl sulfoxide (DMSO) to obtain a 2 wt% PVDF solution, and then barium titanate powder was added. Magnetic stirring and ultrasonic dispersion were performed to obtain a 10% barium titanate dispersion in an organic solvent. The mass of the barium titanate was twice that of the PVDF.

[0066] (2) Preparation of sodium ion battery negative electrode

[0067] The sodium metal sheet was placed on the base of the spin coater, and the organic solvent dispersion of barium titanate prepared in the above step (1) was spin-coated on the surface of the sodium metal sheet using a pipette (spin coating speed 6000 r / min, spin coating 60 s). After drying, a sodium ion battery negative electrode with barium titanate and PVDF (thickness 500 nm) on the surface was obtained.

[0068] (3) Preparation of sodium ion batteries

[0069] The method is the same as step (4) of Example 1.

[0070] Comparative Example 4: Preparation of a sodium ion battery with sodium metal sheets coated only with PVDF

[0071] The preparation steps of this comparative example are basically the same as those of comparative example 3, except that barium titanate is not added in step (2).

[0072] Comparative Example 5: Preparation of a Sodium Ion Battery with an Anode Coated with an Artificial Solid Electrolyte Interface Film (IV)

[0073] The preparation steps of this comparative example are basically the same as those of Example 1, except that the barium titanate in step (2) is replaced by aluminum oxide (with a dielectric constant of about 10).

[0074] Example 4: Sodium Ion Battery Performance Testing

[0075] The relevant properties of the sodium ion batteries prepared in the above Examples 1-3 and Comparative Examples 1-5 were tested as follows.

[0076] (1) Negative electrode ion transport performance

[0077] According to Joule, Volume 3, Issue 11, 2761-2776 (see:

[0078] The negative electrode ion transport performance was tested using the method described in

[15] . The test results are shown in Table 1 below, where the effective ionic conductivity is the ionic conductivity of the electrolyte multiplied by the sodium ion migration number, because anion and cation migration exist simultaneously in the electrolyte, and only sodium ion migration is effective.

[0079] Table 1 Test results of ion transport performance of sodium ion battery negative electrode

[0080]

[0081] (2) Negative electrode cycle stability

[0082] According to Joule, Volume 3, Issue 11, 2761-2776 (see:

[0083] The negative electrode cycling stability was tested using the method of https: / / doi.org / 10.1016 / j.joule.2019.07.025 (current density 1 mA, charge capacity 1 mAh). The test results are as follows: Figure 3 , as shown in Table 2.

[0084] Table 2. Test results of sodium ion battery negative electrode cycle stability

[0085]

[0086] Depend on Figure 3 The results in Table 2 show that the sodium ion batteries of Examples 1-3 have excellent cycle stability compared to the sodium ion batteries of Comparative Examples 1-5. The reasons are as follows: the present invention constructs a functionalized artificial solid electrolyte interface membrane, and utilizes sodium-naphthol with single ion conduction and high ionic conductivity to achieve a stable SEI interface and efficient sodium ion transport; the dynamic regulation of the interface electric field by a trace amount of giant dielectric ceramic (BaTiO3) is used to achieve a balanced interface electric field and a uniform sodium ion beam, thereby suppressing sodium dendrites from the source; and the composite of organic sodium-naphthol and inorganic giant dielectric ceramic improves the stability of the artificial solid electrolyte interface membrane while synergistically enhancing its single and fast sodium ion transport characteristics. Thus, the present invention realizes the application of a single-ion artificial interface layer with an electric field balancing mechanism in the construction of a highly stable sodium metal negative electrode.

[0087] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these changes and variations. The above embodiments or implementation methods are merely illustrative of the present invention, and the present invention may also be implemented in other specific ways or other specific forms without departing from the gist or essential features of the present invention. Therefore, the described implementation methods should be regarded as illustrative and not restrictive in any respect. The scope of the present invention should be described by the appended claims, and any changes that are equivalent to the intent and scope of the claims should also be included within the scope of the present invention.

Claims

1. An artificial solid electrolyte interface membrane, characterized in that: The artificial solid electrolyte interface film contains sodium naphthol and giant dielectric ceramic powder material, and the mass ratio of the sodium naphthol to the giant dielectric ceramic powder material is 1:1-19.

2. The artificial solid electrolyte interface membrane according to claim 1, characterized in that: The giant dielectric ceramic powder material is selected from barium titanate and / or lead zirconate titanate.

3. A method for preparing an artificial solid electrolyte interface membrane according to claim 1 or 2, characterized in that: The preparation method comprises the following steps: (1) preparing the sodium naphthol; (2) Adding the giant dielectric ceramic powder material to the organic solvent solution of sodium naphthol, fully dispersing the powder to obtain an organic solvent dispersion of an artificial solid electrolyte interface membrane, and drying the dispersion to obtain the artificial solid electrolyte interface membrane.

4. The preparation method according to claim 3, wherein: In step (1), the naphthol aqueous solution is titrated with sodium hydroxide solution to a pH of 6.5-7.5, and then dried to obtain the sodium naphthol.

5. The preparation method according to claim 3, wherein: In step (2), the organic solvent is selected from dimethyl sulfoxide and / or tetrahydrofuran.

6. The preparation method according to claim 3, wherein: In step (2), the mass percent concentration of the organic solvent solution of sodium naphthol is 2-20%.

7. The preparation method according to claim 3, wherein: In step (2), the mass percentage content of the giant dielectric ceramic powder material in the organic solvent dispersion of the artificial solid electrolyte interface membrane is 0.5-95%.

8. A sodium ion battery negative electrode, characterized in that: The sodium ion battery negative electrode is coated with the artificial solid electrolyte interface film according to claim 1 or 2 on the surface of the sodium metal sheet.

9. A method for preparing a negative electrode for a sodium ion battery according to claim 8, characterized in that: The preparation method is to add the organic solvent dispersion of the artificial solid electrolyte interface membrane according to claim 1 or 2 to the surface of a sodium metal sheet, and obtain the sodium ion battery negative electrode after drying.

10. A sodium ion battery, characterized in that: The sodium ion battery comprises the sodium ion battery negative electrode according to claim 8.

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