CN109378433B - Separator, method for producing same, and electrochemical cell - Google Patents
Separator, method for producing same, and electrochemical cell Download PDFInfo
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- CN109378433B CN109378433B CN201811288724.5A CN201811288724A CN109378433B CN 109378433 B CN109378433 B CN 109378433B CN 201811288724 A CN201811288724 A CN 201811288724A CN 109378433 B CN109378433 B CN 109378433B
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- ROOXNKNUYICQNP-UHFFFAOYSA-N ammonium persulfate Chemical compound [NH4+].[NH4+].[O-]S(=O)(=O)OOS([O-])(=O)=O ROOXNKNUYICQNP-UHFFFAOYSA-N 0.000 claims description 8
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Images
Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/409—Separators, membranes or diaphragms characterised by the material
- H01M50/431—Inorganic material
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/403—Manufacturing processes of separators, membranes or diaphragms
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/409—Separators, membranes or diaphragms characterised by the material
- H01M50/411—Organic material
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/409—Separators, membranes or diaphragms characterised by the material
- H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Inorganic Chemistry (AREA)
- Laminated Bodies (AREA)
- Cell Separators (AREA)
- Secondary Cells (AREA)
Abstract
The invention discloses a diaphragm which comprises a porous base membrane and an enhanced modified layer directly combined with the surface of the porous base membrane, wherein the enhanced modified layer is made of a graphene-like material. The invention also discloses an electrochemical battery, which comprises a positive electrode, a negative electrode and the diaphragm, wherein the diaphragm is arranged between the positive electrode and the negative electrode. The invention also discloses a preparation method of the diaphragm, which comprises the following steps: providing the reinforcement modification layer; and directly bonding the reinforcement modification layer to the surface of the porous base membrane.
Description
Technical Field
The present invention relates to the field of batteries, and in particular to a separator, a method for preparing the same, and an electrochemical cell.
Background
Along with the rapid development of new energy automobiles, particularly the rise of internet vehicle manufacturing movement in recent two years, the battery market is confronted with a rapidly increasing opportunity, the energy density of the battery and the safety problem of the battery also become short board factors which restrict the further large-scale application of the battery, and how to improve and solve the safety problem of the battery and improve the energy density of the battery becomes a research hotspot of the industry.
The safety problems of electrochemical cells are mainly caused by the short-circuiting of the positive and negative contacts. The separator serves as an important component of an electrochemical cell and serves to separate the positive and negative electrodes. The mechanical strength and stability of the separator greatly improve the safety of the battery. At present, the improvement of the diaphragm is widely used for forming a ceramic coating layer on the surface of the diaphragm so as to improve the strength of the diaphragm, but the ceramic coating layer is easy to fall off when being soaked in electrolyte, and the stability of the diaphragm is influenced.
Disclosure of Invention
Accordingly, there is a need for a separator having high mechanical strength and good stability, which can improve the energy density of a battery, a method for preparing the same, and an electrochemical battery.
A diaphragm comprises a porous base membrane and a reinforced modified layer directly combined with the surface of the porous base membrane, wherein the reinforced modified layer is made of a graphene-like material.
In one embodiment, the graphene-like material comprises one or more of hexagonal boron nitride, graphene, graphite phase carbon nitride, and a two-dimensional transition metal disulfide.
In one embodiment, the graphene-like material is attached to the porous base membrane by covalent bonds.
In one embodiment, each intact graphene-like material is capable of covering more than 80% of the area of the surface of the porous base membrane.
In one embodiment, the thickness of the enhancement modified layer is 2nm to 50 nm.
In one embodiment, the thickness of the porous base film is 5 μm to 30 μm.
In one embodiment, the reinforcing modification layer covers one surface or both opposite surfaces of the porous base membrane.
An electrochemical cell comprising a positive electrode, a negative electrode and said separator, said separator being disposed between said positive electrode and said negative electrode.
In one embodiment, the enhancement modification layer is disposed on a surface of the porous base film near the negative electrode.
A preparation method of the diaphragm comprises the following steps:
providing the reinforcement modification layer; and
directly bonding the reinforcement modification layer to the surface of the porous base membrane.
In one embodiment, the step of providing the reinforcement modification layer comprises:
providing a substrate, and depositing and forming the enhancement modified layer on the substrate; and
and stripping the reinforced modified layer from the substrate.
In one embodiment, the step of peeling the reinforcement modification layer from the substrate comprises:
forming a supporting protective layer on the surface of the reinforced modified layer to obtain a composite structure in which the substrate, the reinforced modified layer and the supporting protective layer are sequentially laminated; and
and removing the substrate in the composite structure through etching liquid.
In one embodiment, the substrate is a copper substrate, and the etching liquid is an ammonium persulfate solution.
In one embodiment, the step of forming the support shield layer comprises:
supporting a polymer solution on the surface of the reinforced modified layer; and
drying the reinforced modified layer loaded with the polymer solution.
In one embodiment, the polymer solution is a polymethylmethacrylate solution.
In one embodiment, the step of directly bonding the reinforcement modification layer to the surface of the porous base membrane comprises:
and laminating the reinforced modified layer on the surface of the porous base membrane and then heating, wherein the heating temperature is 80-100 ℃.
In one embodiment, the method further comprises the step of removing the support and protection layer by dissolving the support and protection layer with a solvent after directly bonding the reinforcement modification layer to the surface of the porous base film.
In one embodiment, the material of the supporting and protecting layer comprises polymethyl methacrylate, and the solvent is acetone.
According to the invention, the surface of the porous base membrane is combined with the enhanced modification layer of the graphene-like material, the graphene-like material has pores and can allow ions to pass through, and the diaphragm can be used for isolating the positive electrode and the negative electrode of the electrochemical cell. The graphene-like material is high in mechanical strength, the strength of the diaphragm can be improved, and the phenomenon that the porous base film is damaged by puncture to cause short circuit of the anode and the cathode is avoided. The porous base membrane and the reinforced modified layer are directly combined without using a binder, so that the phenomenon that the reinforced modified layer falls off due to swelling of the binder in electrolyte is avoided, and the combination stability of the porous base membrane and the reinforced modified layer can be improved.
Drawings
FIG. 1 is a schematic structural diagram of a diaphragm according to an embodiment of the present invention;
FIG. 2 is a schematic structural diagram of a diaphragm according to another embodiment of the present invention;
fig. 3 is a schematic diagram of a process for preparing a separator according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the separator, the method for manufacturing the same, and the electrochemical cell of the present invention are further described in detail by way of examples with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
Referring to fig. 1, an embodiment of the present invention provides a separator, including a porous base film 10 and a reinforcing modification layer 20 directly bonded to a surface of the porous base film 10, where the reinforcing modification layer 20 is a graphene-like material. The separator is soaked in the electrolyte so that ions can pass through the porous base film 10 and the reinforcement modification layer 20 along the bonding direction.
According to the embodiment of the invention, the surface of the porous base membrane 10 is combined with the enhanced modified layer 20 made of the graphene-like material, the graphene-like material has pores and can allow ions to pass through, and the diaphragm can be used for isolating the positive electrode and the negative electrode of the electrochemical cell. The graphene-like material has high mechanical strength, can improve the strength of the diaphragm, and avoids the short circuit of the positive electrode and the negative electrode caused by puncture damage of the porous base film 10. The porous base membrane 10 and the reinforced modified layer 20 are directly bonded without using a binder, so that the phenomenon that the reinforced modified layer 20 falls off due to swelling of the binder in an electrolyte is avoided, and the bonding stability of the porous base membrane 10 and the reinforced modified layer 20 can be improved.
In one embodiment, the porous base membrane 10 may be a polyolefin material. The polyolefin material may comprise one or more of polyethylene, polypropylene and a polyethylene and polypropylene composite. The polyolefin material has good mechanical property and chemical stability and certain puncture resistance.
In the embodiment of the present invention, the graphene-like material is also referred to as a two-dimensional layered material, may have a stacked structure of 1 to 10 monoatomic layers, has high mechanical strength, can be formed by deposition, has a thickness of a nanometer level, and serves as the enhancement modification layer 20 in the embodiment of the present invention. In one embodiment, the graphene-like material may include one or more of hexagonal boron nitride, graphene, graphite phase carbon nitride (g-C3N4), and two-dimensional transition metal dichalcogenide monolayers (TMD layers). The two-dimensional transition metal dichalcogenide may comprise TiS2Lamellar crystal, TiSe2Layered crystal, NbSe2Lamellar crystals, TaS2Lamellar crystals, WS2Layered crystal and MoS2One or more of lamellar crystals. Preferably, the graphene-like material is hexagonal boron nitride, the hexagonal boron nitride is an insulator material, and the graphene-like material has excellent thermal stability, chemical inertness and in-plane mechanical strength, so that the strength of the diaphragm is improved, and the short circuit of the positive electrode and the negative electrode caused by the breakage of the porous base membrane 10 is avoided.
In one embodiment, the graphene-like material may be connected to the porous base film 10 through a covalent bond. Compared with bonding by a binder, the embodiment of the invention bonds the reinforcing modified layer 20 and the porous base membrane 10 by a covalent bond, so that the bonding between the reinforcing modified layer 20 and the porous base membrane 10 is firmer, and the reinforcing modified layer 20 is not easy to fall off in an electrolyte.
In one embodiment, each complete graphene-like material can cover more than 80% of the area of the surface of the porous base membrane 10. The graphene-like material basically covers the surface of the porous base membrane 10, so that the puncture resistance of most of the surface of the porous base membrane 10 can be improved, and the damage probability of the diaphragm is reduced.
In one embodiment, the reinforcing modification layer 20 is a graphene-like material nanosheet, which is directly bonded to the porous base membrane 10 to form the separator. Because the coating thickness of the traditional ceramic coating layer is difficult to control, and the enhanced modification layer 20 of the embodiment of the invention is not combined with the porous base membrane 10 in a coating manner, the thickness of the graphene-like material nanosheet is easy to control, the thickness of the diaphragm is reduced, and the energy density of the battery is improved.
In one embodiment, the thickness of the porous base film 10 may be 5 μm to 30 μm. The thickness of the porous base membrane 10 may be determined according to the capacity of an electrochemical cell to be used, and for an electrochemical cell with a larger capacity, the piercing strength of the separator is greater, and the thickness of the porous base membrane 10 may be increased; for electrochemical cells with smaller capacities, the separator has less puncture strength and the thickness of the porous base membrane 10 can be made smaller. In one embodiment, the capacity of the electrochemical cell is about 100mAh to 5000mAh, and the thickness of the porous base film 10 may be 5 μm to 20 μm. In another embodiment, the capacity of the electrochemical cell is about 5Ah to 200Ah, and the thickness of the porous base film 10 may be 10 μm to 30 μm.
In one embodiment, the thickness of the enhancement modified layer 20 may be 2nm to 50 nm. Likewise, the thickness of the reinforcement modification layer 20 may be determined according to the capacity of the electrochemical cell in which it is used. In one embodiment, the electrochemical cell has a capacity of about 100mAh to about 5000mAh, and the thickness of the reinforcing modification layer 20 may be 2nm to 30 nm. In another embodiment, the electrochemical cell has a capacity of about 5Ah to about 200Ah, and the reinforcement modification layer 20 may have a thickness of about 30nm to about 50 nm.
Referring to fig. 1 and 2, in one embodiment, the reinforcement modification layer 20 may be bonded to one surface or both opposite surfaces of the porous base film 10 to form a separator of a single reinforcement modification layer 20 or a separator of a dual reinforcement modification layer 20.
The embodiment of the invention also provides an electrochemical battery, which comprises a positive electrode, a negative electrode and the diaphragm, wherein the diaphragm is arranged between the positive electrode and the negative electrode and used for insulating and isolating the positive electrode and the negative electrode. The electrochemical cell may be a lithium ion cell, a sodium ion cell, and a magnesium ion cell.
In one embodiment, the reinforcement modification layer 20 is disposed on a surface of the porous base film 10 near the negative electrode. In the cycle process of the electrochemical cell, the piercing of the separator is greatly influenced by factors from the negative electrode, and the separator on the negative electrode side of the cell is prone to metal precipitation, for example, the lithium ion cell is prone to metal lithium precipitation on the negative electrode, the precipitated metal can easily pierce the separator on the negative electrode side, and the enhancement modified layer 20 is arranged on the surface close to the negative electrode, so that the precipitated metal can be better blocked, and the porous base film 10 can be protected from piercing. The reinforcing modification layer 20 may also be disposed on both surfaces of the porous base film 10, respectively opposite to the positive electrode and the negative electrode, to ensure that the porous base film 10 is not punctured by factors from the positive electrode and from the negative electrode.
Referring to fig. 3, an embodiment of the present invention further provides a method for preparing the separator, including:
s100, providing the reinforced modified layer 20; and
and S200, directly combining the reinforcing modification layer 20 with the surface of the porous base membrane 10.
In step S100, the enhancement modified layer 20 may be a nanosheet prepared by a chemical vapor deposition method, and the enhancement modified layer 20 with a more uniform and thinner thickness can be obtained by the chemical vapor deposition method, which is beneficial to reducing the thickness of the separator and improving the energy density of the electrochemical cell.
In one embodiment, the step of providing the reinforcement modification layer 20 may include:
s110, providing a substrate 30, and depositing and forming the enhancement modified layer 20 on the substrate 30; and
and S120, peeling the reinforced modified layer 20 from the substrate 30.
In step S110, the substrate 30 may be a metal substrate 30, and the reinforcement modification layer 20 is more easily peeled off from the substrate 30 in step S120 using the metal substrate 30. In one embodiment, the metal substrate 30 may be selected from one of copper, nickel and germanium. The substrate 30 is preferably copper. The deposition may be chemical vapor deposition, and the enhancement modified layer 20 formed may be a graphene-like material nanosheet.
In one embodiment, the enhancement modified layer 20 is a boron nitride material. The step of depositing the enhancement modification layer 20 may include: s111, decomposing a compound containing boron and a compound containing nitrogen and/or a compound containing boron and nitrogen to form a boron precursor and a nitrogen precursor; and S112, introducing the mixed gas of the boron precursor gas and the nitrogen precursor gas into a vapor deposition reaction chamber containing the substrate 30 to perform chemical vapor deposition reaction, and depositing the boron nitride enhanced modified layer 20 on the substrate 30.
In step S111, the boron element-containing compound may include at least one of diborane and a boron halide. The nitrogen element-containing compound may include ammonia gas. The boron and nitrogen element containing compound may include one or more of ammonia borane, borazine, and borazine. Preferably, the boron-containing compound and the nitrogen-containing compound are used to deposit the boron nitride enhancement modified layer 20, the boron precursor gas formed by decomposition is hydrogen boride, and the nitrogen precursor gas is ammonia gas, so that the purity of the enhancement modified layer 20 is higher.
In step S112, in one embodiment, the boron precursor gas and the nitrogen precursor gas are carried into the vapor deposition reaction chamber by a carrier gas. The carrier gas may be one or more of hydrogen, argon and nitrogen. Preferably, the carrier gas may be hydrogen gas, so that the vapor deposition reaction chamber is a reducing atmosphere to ensure that the substrate 30 is not oxidized.
In one embodiment, the flow ratio of the mixed gas of the boron precursor gas and the nitrogen precursor gas to the carrier gas may be (3-5): 1, preferably 4: 1.
In one embodiment, the system pressure of the chemical vapor deposition reverse chamber may be 1Pa to 10 Pa5Pa。
In one embodiment, the temperature of the chemical vapor deposition reaction may be 800 ℃ to 1500 ℃. The time of the chemical vapor deposition reaction can be 10min to 30 min.
In an embodiment, the method further includes a step of cooling after the chemical vapor deposition reaction is performed, and the chemical vapor deposition reaction is stopped by cooling so that the formed enhancement modified layer 20 is stable. The cooling rate of the chemical vapor deposition reaction when the temperature is reduced to room temperature can be 1 ℃/min to 20 ℃/min. The cooling rate and the deposition reaction time may be determined according to the thickness of the enhancement modified layer 20 to be obtained, and the deposition thickness of the enhancement modified layer 20 is controlled by controlling the deposition reaction time.
In step S120, the step of peeling the reinforcement modification layer 20 from the substrate 30 may include:
s121, forming a supporting protective layer 40 on the surface of the reinforced modified layer 20 to obtain a composite structure in which the substrate 30, the reinforced modified layer 20 and the supporting protective layer 40 are sequentially laminated; and
s122, removing the substrate 30 in the composite structure through etching liquid.
In one embodiment, the step of forming the support shield 40 comprises:
supporting a polymer solution on the surface of the reinforced modified layer 20; and
the reinforcement modification layer 20 loaded with the polymer solution is dried.
The support protective layer 40 serves as a support structure to make the reinforcement modification layer 20 have a certain thickness for easier transfer after the substrate 30 is peeled off from the reinforcement modification layer 20. Meanwhile, the support protective layer 40 is formed on the surface of the enhancement modified layer 20, so that the enhancement modified layer 20 is prevented from being directly exposed to the etching solution and damaged. In one embodiment, the polymer solution may be a polymethylmethacrylate solution.
In an embodiment, the substrate 30 is a copper substrate 30, and the etching solution is an ammonium persulfate solution.
In step S200, the step of directly bonding the reinforcement modification layer 20 to the porous base film 10 may include:
and laminating the reinforced modified layer 20 on the surface of the porous base membrane 10 point for heating, wherein the heating temperature is 80-100 ℃.
In one embodiment, the heating time may be 20 minutes to 60 minutes. The properties and structure of the porous base film 10 are not damaged in the heating temperature and the heating time range, while the reinforcement modification layer 20 and the porous base film 10 may be combined.
In one embodiment, the method further comprises the following steps: a step of removing the support and protection layer 40 by dissolving the support and protection layer 40 by a solvent after directly bonding the reinforcement modification layer 20 to the surface of the porous base film 10.
In one embodiment, the material of the supporting and protecting layer 40 is polymethyl methacrylate, and the solvent may be acetone.
Preferably, the method further comprises the following steps: a step of cleaning the membrane with a protective gas after removing the support and protection layer 40. The purity and the non-oxidation of the diaphragm are ensured by cleaning in a protective atmosphere. The reducing gas may be nitrogen.
Examples
Preparation of boron nitride nanosheet (enhanced modified layer 20):
the copper foil after the chemical polishing treatment is annealed for 1h in a hydrogen atmosphere of 5sccm at 1000 ℃ so that the substrate 30 is rapidly cooled to avoid oxidation.
Ammonia borane is heated to 70 ℃ below zero in a separated quartz container and then decomposed into precursor gases of hydrogen boride and ammonia gas, and then the precursor gases are introduced into a vapor deposition reaction chamber through hydrogen carrier gas. After the deposition growth is carried out for about 10min to 30min, the temperature of the vapor deposition reaction cavity is rapidly reduced to the room temperature. The growth thickness of the nano-sheet is controlled to be 2 nm-50 nm by controlling the growth time.
Transfer of boron nitride nanosheets (enhanced modification layer 20) to the porous base membrane 10:
and spin-coating a layer of polymethyl methacrylate (PMMA) with the mass fraction of 2% on the surface of the boron nitride nanosheet grown on the copper foil, and airing to form a composite structure in which the substrate 30, the enhanced modified layer 20 and the supporting protective layer 40 are sequentially laminated.
And placing the composite structure in ammonium persulfate solution for soaking, etching away the copper foil, and cleaning with deionized water.
And laminating the reinforced modified layer 20 on the surface of the porous base membrane 10, drying and heating on a heating table at 80-100 ℃ for about half an hour.
And cleaning the PMMA by using acetone, and finally cleaning the PMMA by using nitrogen to obtain the diaphragm.
The boron nitride was assembled facing the negative electrode to form an electrochemical cell. The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (11)
1. An electrochemical cell, characterized in that the electrochemical cell is a lithium ion cell, a sodium ion cell or a magnesium ion cell, and comprises a positive electrode, a negative electrode and a diaphragm, the diaphragm is arranged between the positive electrode and the negative electrode, the diaphragm comprises a porous base membrane (10) and a reinforcing modification layer (20) directly combined with the surface of the porous base membrane (10), the material of the reinforcing modification layer (20) is a graphene-like material, the reinforcing modification layer (20) is arranged on the surface of the porous base membrane (10) close to the negative electrode, the thickness of the reinforcing modification layer (20) is 2nm to 50nm, the thickness of the porous base membrane (10) is 5 μm to 30 μm, the graphene-like material is connected with the porous base membrane (10) through a covalent bond, and the graphene-like material is not connected with the porous base membrane (10) through a binder, each intact graphene-like material is capable of covering more than 80% of the area of the surface of the porous base membrane (10).
2. The electrochemical cell of claim 1, wherein the graphene-like material comprises one or more of hexagonal boron nitride, graphene, graphite phase carbon nitride, and two-dimensional transition metal dichalcogenides.
3. The electrochemical cell according to claim 1, wherein the separator is prepared by a method comprising:
providing the reinforcement modification layer (20); and
directly bonding the reinforcement modification layer (20) to the surface of the porous base membrane (10).
4. The electrochemical cell according to claim 3, wherein the step of providing the reinforcement modification layer (20) comprises:
providing a substrate (30), and depositing and forming the enhancement modified layer (20) on the substrate (30); and
peeling the reinforcement modification layer (20) from the substrate (30).
5. The electrochemical cell according to claim 4, wherein the step of peeling the reinforcement modification layer (20) from the substrate (30) comprises:
forming a supporting protective layer (40) on the surface of the reinforced modified layer (20) to obtain a composite structure in which the substrate (30), the reinforced modified layer (20) and the supporting protective layer (40) are sequentially laminated; and
removing the substrate (30) in the composite structure by means of an etching liquid.
6. The electrochemical cell according to claim 5, wherein the substrate (30) is a copper substrate (30) and the etching solution is an ammonium persulfate solution.
7. The electrochemical cell according to claim 5, wherein the step of forming the support and protection layer (40) comprises:
supporting a polymer solution on the surface of the reinforced modified layer (20); and
drying the reinforcement modification layer (20) loaded with the polymer solution.
8. The electrochemical cell of claim 7, wherein the polymer solution is a polymethylmethacrylate solution.
9. The electrochemical cell according to claim 3, wherein the step of directly bonding the reinforcement modification layer (20) to the surface of the porous base membrane (10) comprises:
and laminating the reinforced modified layer (20) on the surface of the porous base membrane (10) and heating the laminated layer at the temperature of 80-100 ℃.
10. The electrochemical cell according to claim 5, further comprising a step of removing the supporting and protecting layer (40) by dissolving the supporting and protecting layer (40) by a solvent after directly bonding the reinforcing modification layer (20) to the surface of the porous base film (10).
11. The electrochemical cell according to claim 10, wherein the material of the support and protection layer (40) comprises polymethylmethacrylate and the solvent is acetone.
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