CN108933216B - Diaphragm containing graphene/cellulose composite material and preparation method thereof - Google Patents
Diaphragm containing graphene/cellulose composite material and preparation method thereof Download PDFInfo
- Publication number
- CN108933216B CN108933216B CN201710392500.8A CN201710392500A CN108933216B CN 108933216 B CN108933216 B CN 108933216B CN 201710392500 A CN201710392500 A CN 201710392500A CN 108933216 B CN108933216 B CN 108933216B
- Authority
- CN
- China
- Prior art keywords
- cellulose
- graphene
- composite material
- diaphragm
- graphite
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- 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
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
-
- 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
- H01M50/44—Fibrous 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
Abstract
The invention discloses a diaphragm containing a graphene/cellulose composite material and a preparation method thereof, wherein the diaphragm comprises a diaphragm base layer, a graphene/cellulose composite material layer on the surface of the diaphragm base layer facing to a positive plate side and/or a graphene/cellulose composite material layer on the surface of the diaphragm base layer facing to a negative plate side, and the graphene/cellulose composite material layer comprises graphene, cellulose and other auxiliary agents; the diaphragm containing the graphene/cellulose composite material has the characteristics of low thickness, high liquid absorption amount and low resistance in the using process, so that the lithium ion battery has high capacity and long service life, wherein the graphene component can also effectively form a heat transmission network, and the heat is timely dissipated when the local overheating phenomenon occurs, so that the heat resistance of the diaphragm is improved, and the safety performance of the battery is improved. The preparation method of the diaphragm is simple, the reaction condition is mild, the preparation period is short, and large-scale industrial production can be realized.
Description
Technical Field
The invention belongs to the technical field of lithium ion batteries, and particularly relates to a diaphragm containing a graphene/cellulose composite material and a preparation method thereof.
Background
Lithium ion batteries generally use materials containing lithium as electrodes, and are representative of modern high-performance batteries. It is popular with researchers because of its advantages of small size, light weight, high working voltage, large specific energy, long cycle life, no pollution, etc. Can be widely appliedIn the fields of aerospace, electronic devices, and daily life. The lithium ion battery used at present generally consists of a positive electrode, a negative electrode, an electrolyte and a diaphragm. Separators are one of the key internal components of lithium ion batteries, which operate primarily by movement of lithium ions between a positive electrode and a negative electrode. During charging and discharging, Li+Li being inserted and extracted back and forth between two electrodes, i.e. during charging+The lithium ion battery is extracted from the positive electrode and is inserted into the negative electrode through the electrolyte, and the negative electrode is in a lithium-rich state; the opposite is true during discharge. The diaphragm has the main functions of isolating the positive electrode and the negative electrode and preventing electrons from passing through, and can allow lithium ions to pass through, so that the lithium ions are rapidly transmitted between the positive electrode and the negative electrode in the charging and discharging process.
Currently, the common diaphragm in lithium ion batteries is a multilayer structure or a ceramic-coated diaphragm; the positive and negative electrode materials and the supporting function can be well blocked, local heating can be generated when the diaphragm is punctured, the diaphragm blocking layer can prevent the battery from thermally exploding and exploding if the diaphragm blocking layer can rapidly melt closed holes, and the blocking function cannot be achieved when the local heating speed is higher than the melting speed. Moreover, after long-term use, the metallic lithium crystallizes on the negative electrode to form dendritic metallic lithium-dendrite; when the dendrite grows to a certain degree, the dendrite can pierce a diaphragm to cause short circuit in the battery, and the personal safety is seriously threatened, so that the service life of the lithium ion battery is seriously prolonged, and the energy density and the theoretical capacity of the lithium ion battery are seriously limited.
Moreover, the energy density and the actual capacity of the lithium ion battery prepared by the existing process are relatively low, and the requirements of people cannot be met; the main reason is that the performance of the diaphragm directly affects the internal resistance, discharge capacity, cycle service life and safety performance of the battery, so that the consistency of the lithium ion battery is extremely high, and the manufacturing of the lithium ion battery has high requirements on the uniformity of the size and distribution of the micropores of the diaphragm besides the basic requirements of thickness, surface density and mechanical properties.
Graphene is a new material with a single-layer sheet structure formed by carbon atoms, is the thinnest and hardest nano material, has ultra-light and thin properties, ultra-high mechanical strength, unique air resistance, high specific surface area and surface activity, and has the characteristics of high temperature resistance, corrosion resistance and high lubrication of common graphite. The single-layer graphene has the theoretical thickness of 0.334 nanometer, extremely high heat conductivity coefficient and extremely high electron migration speed, is the material with the lowest resistivity at present, is expected to be used for developing a new generation of thinner and faster electric conduction element or transistor, is a novel electric conduction and heat conduction material which is mainly researched and produced in the world at present, and can be widely applied to the industrial fields of mobile equipment, aerospace, new energy batteries, biomedicine and the like in the future. The nano-scale graphite particles are prepared by grinding pure natural crystalline flake graphite for a long time, performing high-speed centrifugal separation, condensing and filter pressing by adopting a special technology and an advanced production process, and are novel materials for producing high-quality graphene.
Disclosure of Invention
In order to solve the disadvantages of the prior art, it is an object of the present invention to provide a separator including a graphene/cellulose composite material, the separator including a separator base layer, a graphene/cellulose composite material layer on a surface of a side facing a positive electrode, and/or a graphene/cellulose composite material layer on a surface of a side facing a negative electrode, and a method of preparing the same.
The invention also provides a lithium ion battery, which comprises the separator.
The graphene material has good electron transmission capability in the lamellar direction, is widely applied to the research of various electronic devices, and can reduce the internal resistance between corresponding electrode materials if being compounded with the electrode materials, so that the charge and discharge capacity of the battery is improved. However, in the actual operation process, the graphene lamellar structure is difficult to disperse in a liquid phase system at high concentration; and when the graphene composite diaphragm is compounded with the diaphragm, a binder needs to be added to enable the composite structure to exist stably, so that the production difficulty of the graphene composite diaphragm is greatly increased. Through a large number of experiments, researchers find that cellulose is a material which can be well dispersed in a liquid phase system, and meanwhile, the cellulose also has the characteristic of high temperature resistance. The graphene/cellulose composite material can be prepared by performing ball milling treatment on graphite and cellulose according to a certain proportion, stripping the number of the graphite layers can be realized under the action of the cellulose by adopting a ball milling treatment mode, so that the thickness of the graphite which is not subjected to oxidation treatment is thinner, the graphene is obtained by stripping, and the cellulose can be grafted (or combined) between or on the graphene layers obtained by stripping, so that the graphene is more stable in slurry. Meanwhile, the composite material has good solubility in water, can prepare slurry with higher concentration, and when the composite material is coated on the surface of a diaphragm substrate, the obtained coating is well bonded on the surface of the substrate. The present invention has been completed based on the above-mentioned ideas.
The first aspect of the invention provides a diaphragm containing a graphene/cellulose composite material, which comprises a diaphragm base layer, a graphene/cellulose composite material layer on the surface of the diaphragm base layer facing to a positive electrode side and/or a graphene/cellulose composite material layer on the surface of the diaphragm base layer facing to a negative electrode side, wherein the graphene/cellulose composite material layer comprises graphene, cellulose and other auxiliary agents, one part of the cellulose is embedded between sheets of the graphene, and the other part of the cellulose is attached to the surface of the sheet of the graphene; the other auxiliary agent is at least one of a surfactant and a dispersing agent.
According to the invention, the thickness of the separator is 5 to 100. mu.m, preferably 10 to 60 μm, for example 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm.
According to the present invention, the separator base layer is a single-layer separator made of one material selected from polypropylene, polyethylene, polyvinylidene fluoride-hexafluoropropylene copolymer, polyester, glass fiber, aramid, and polyimide, or a multi-layer separator made of two or more materials.
According to the invention, the thickness of the membrane substrate is 2-90 μm, preferably 10-50 μm, such as 10 μm, 20 μm, 30 μm, 40 μm, 50 μm.
According to the invention, the graphene/cellulose composite layer has a thickness of 0.1 to 10 μm, for example 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 8 μm, 10 μm.
According to the present invention, the porosity of the separator base layer is 30% to 70%.
According to the invention, the graphene/cellulose composite layer is obtained by a method comprising the following steps:
(a) mixing and grinding graphite and cellulose to prepare a mixed material;
(b) dissolving the mixed material obtained in the step (a) in water, adding other auxiliaries, and uniformly mixing to obtain mixed slurry of the graphene/cellulose composite material;
(c) coating the mixed slurry of step (b) on one or both surfaces of the separator base layer;
(d) drying the diaphragm coated with the mixed slurry in the step (c) to prepare a graphene/cellulose composite material layer attached to the surface of one side or two sides of the diaphragm base layer;
wherein the other auxiliary agent is at least one selected from a surfactant and a dispersing agent.
A second aspect of the present invention provides a method for preparing the above-described separator comprising a graphene/cellulose composite, the method comprising the steps of:
(1) mixing and grinding graphite and cellulose to prepare a mixed material;
(2) dissolving the mixed material obtained in the step (1) in water, adding other auxiliaries, and uniformly mixing to obtain mixed slurry of the graphene/cellulose composite material;
(3) coating the mixed slurry of the step (2) on one side or two side surfaces of the diaphragm base layer;
(4) drying the diaphragm base layer coated with the mixed slurry in the step (3) to obtain the diaphragm containing the graphene/cellulose composite material;
wherein the other auxiliary agent is at least one selected from a surfactant and a dispersing agent.
According to the invention, in step (a) or step (1), the grinding is preferably carried out in a ball mill for 5 to 24 hours; the grinding temperature is room temperature.
According to the invention, in step (b) or step (2), the mass ratio of the mixed material to water is (0.1-50):100, preferably (0.5-33):100, and more preferably (1-15): 100.
According to the invention, in step (c) or step (3), the coating is at least one selected from spray coating, blade coating, coating roll, coating brush and the like.
According to the invention, in the step (d) or the step (4), the drying time is 1-24 h; the drying temperature is 30-80 ℃.
In the first and second aspects, the graphite is selected from one or a mixture of natural crystalline flake graphite, crystalline graphite, microcrystalline graphite and synthetic graphite; the cellulose is selected from one or more of natural cellulose and derivatives thereof.
Preferably, the graphite is selected from natural flake graphite; the cellulose is selected from methyl cellulose, ethyl cellulose, hydroxymethyl cellulose, cellulose acetate, hydroxyethyl cellulose, and hypromellose.
According to the invention, the thickness of the graphene/cellulose composite material layer is 0.1-10 μm.
According to the invention, the graphene/cellulose composite material layer has a coating surface density of 0.2-5g/m2。
According to the invention, the graphene/cellulose composite material layer comprises graphene, cellulose and other auxiliary agents; the mass ratio of the graphene to the cellulose is (1-70):100, preferably (20-50): 100; the mass ratio of the other auxiliary agents to the cellulose is (1-30):100, preferably (2-20): 100.
According to the invention, the dispersant in the other auxiliary agents comprises one or more of castor oil, dodecyl sulfate, triethyl hexyl phosphoric acid, methyl amyl alcohol, polyacrylamide, polyoxyethylene ether and oleamide.
According to the invention, the surfactant in the other auxiliary agents comprises one or more of dodecyl benzene sulfonate, dioctyl succinate sulfonate, fatty alcohol polyoxyethylene ether, oleyl alcohol polyoxyethylene ether, polyoxyethylene fatty acid ester, oleate and stearate.
According to the invention, the graphene/cellulose composite layer further comprises a binder.
Preferably, the mass ratio of the binder to the cellulose is (0-10):100, preferably (0-5): 100.
According to the invention, the binder comprises one or more of styrene-butadiene rubber, fluorinated rubber, polyvinyl alcohol, hydroxymethyl cellulose salt, polyacrylic acid, polyacrylate and derivatives thereof, polyacrylonitrile, acrylate-acrylonitrile copolymer, polymethyl methacrylate, dimethyl diallyl ammonium chloride, alginate, pectate and antler glue salt.
A third aspect of the present invention is to provide a lithium ion battery comprising the above separator.
Preferably, the lithium ion battery is at least one of a button battery, a stacked battery and a wound battery.
Preferably, the outer package of the lithium ion battery is a soft plastic package or a steel shell package.
The invention has the beneficial effects that:
1. the invention provides a diaphragm containing a graphene/cellulose composite material and a preparation method thereof, wherein the diaphragm comprises a diaphragm base layer, a graphene/cellulose composite material layer on the surface of the diaphragm base layer facing to a positive plate side and/or a graphene/cellulose composite material layer on the surface of the diaphragm base layer facing to a negative plate side, and the graphene/cellulose composite material layer comprises graphene, cellulose and other auxiliary agents; one part of the cellulose is embedded between the graphene sheets, and the other part of the cellulose is attached to the surfaces of the graphene sheets; the other auxiliary agent is at least one of a surfactant and a dispersing agent. The graphene/cellulose composite material layer can be coated on the surface of the diaphragm base layer in a dripping or coating mode, the diaphragm base layer and the composite material can be bonded without adding a binder or only adding a small amount of binder in the coating process, and the bonding effect is very good; moreover, the influence of the binder on the porosity of the diaphragm can be greatly reduced, an effective channel is provided for the transmission of lithium ions, the internal resistance of the diaphragm is reduced, and the charge-discharge cycle performance of the battery is improved; the diaphragm containing the graphene/cellulose composite material has the characteristics of low thickness, high liquid absorption amount and low resistance in the using process, so that the lithium ion battery has high capacity and long service life, wherein the graphene component can also effectively form a heat transmission network, and the heat is timely dissipated when the local overheating phenomenon occurs, so that the heat resistance of the diaphragm is improved, and the safety performance of the battery is improved. The preparation method of the diaphragm is simple, the reaction condition is mild, the preparation period is short, and large-scale industrial production can be realized.
2. The present invention provides a battery comprising the above separator; the battery has good stability in the charge-discharge cycle process, and can still maintain higher specific discharge capacity when the charge-discharge current is larger (10C). In addition, after the battery is circulated for a period of time, the battery is placed at 140 ℃, and observation shows that the open-circuit voltage of the battery does not change obviously after 1 hour, which indicates that the battery can still be used stably when being heated, namely the battery has good safety performance.
Drawings
Fig. 1 is a graph showing the first charge and discharge of the battery obtained in example 1.
Fig. 2 is a graph showing the change of the charge-discharge specific capacity of the battery obtained in example 1 at different rates.
Detailed Description
The invention will be further illustrated with reference to the following specific examples. It should be understood that these examples are only for illustrating the present invention and are not intended to limit the scope of the present invention. Furthermore, it should be understood that various changes or modifications can be made by those skilled in the art after reading the description of the present invention, and equivalents may fall within the scope of the present invention.
In this embodiment, when the prepared lithium ion battery is subjected to a rate charge and discharge test, the lithium ion battery is subjected to a charge and discharge cycle test at different rates of 0.1C, 0.5C, 1C, 2C, 5C, and 10C, and the discharge specific capacities at the corresponding rates are recorded.
In this embodiment, when the prepared lithium ion battery is subjected to a thermal stability test, after the lithium ion battery completes a charge-discharge cycle at a rate of 0.1C for 20 times, the lithium ion battery is placed in a silicon oil bath at a constant temperature of 140 ℃, and simultaneously, the change of the open-circuit voltage of the battery is monitored, and the open-circuit voltage value of the battery after 1 hour is recorded.
Preparing a positive plate: and (3) fully mixing 85 parts of positive active material lithium cobaltate, 5 parts of acetylene black, 5 parts of conductive graphite and 5 parts of PVDF with N-methylpyrrolidone to obtain positive slurry, and uniformly coating the positive slurry on the surface of the aluminum foil current collector to finish the preparation of the positive plate.
Preparing a negative plate: and (3) fully mixing 87 parts of negative active material conductive graphite, 5 parts of acetylene black, 5 parts of sodium hydroxymethyl cellulose binder and 3 parts of styrene butadiene rubber binder with an ethanol-water mixed solution to obtain negative slurry, and uniformly coating the negative slurry on the surface of the copper foil current collector to finish the preparation of the negative plate.
Example 1
Step 1), fully mixing 60g of natural crystalline flake graphite and 100g of methyl cellulose, and performing ball milling at room temperature for 15 hours to obtain composite graphene cellulose material powder;
step 2), dissolving 25g of sodium dodecyl benzene sulfonate in 460mL of water, dissolving 160g of the graphene cellulose material obtained in the step (1) in the water, and fully stirring to obtain graphene cellulose mixed slurry;
step 3) coating the mixed slurry scraper in the step 2) on one side of the polypropylene diaphragm base layer;
step 4) drying the diaphragm base layer coated with the mixed slurry in the step 3) in a vacuum drying oven at 40 ℃ for 2h to prepare the diaphragm containing the graphene/cellulose composite material; the thickness of the graphene/cellulose composite material coating is 2 microns.
Step 5), assembling the lithium ion battery:
and (3) placing the diaphragm of the graphene/cellulose composite material obtained in the step (4) between the positive electrode and the negative electrode piece, enabling the coating direction to face one side of the negative electrode, adding 100 mu L of commercial lithium ion battery electrolyte, placing a reed, and sealing by using a hydraulic sealing machine to prepare the button 2032 lithium ion battery.
And 6) carrying out a multiplying power charge-discharge test and a thermal stability test.
Example 2
Example 1 was repeated with the difference that:
step 1), fully mixing 30g of natural crystalline flake graphite and 100g of ethyl cellulose, and performing ball milling at room temperature for 5 hours to obtain composite graphene cellulose material powder;
step 2) dissolving 15g of methyl amyl alcohol in 1500mL of water, dissolving 145g of the graphene cellulose material obtained in the step 1 in the water, and fully stirring to obtain graphene/cellulose composite slurry;
in the step 4), the thickness of the graphene/cellulose composite material coating is 8 μm.
Example 3
Example 1 was repeated with the difference that:
step 1), fully mixing 10g of crystalline graphite and 100g of ethyl cellulose, and performing ball milling at room temperature for 5 hours to obtain composite graphene cellulose material powder;
step 2) dissolving 0.3g of sodium dodecyl sulfate in 3700mL of water, dissolving 11g of the graphene cellulose material obtained in the step 1 in the water, and fully stirring to obtain graphene/cellulose composite slurry;
in the step 5), the coating direction faces to the positive electrode side.
Example 4
Example 1 was repeated with the difference that:
step 1), fully mixing 15g of natural crystalline flake graphite and 100g of cellulose acetate, and performing ball milling at room temperature for 5 hours to obtain composite graphene cellulose material powder;
step 2) dissolving 0.4g of polyoxyethylene ether in 2000mL of water, dissolving 12g of the graphene cellulose material obtained in the step 1 in the water, and fully stirring to obtain graphene/cellulose composite slurry;
in the step 4), the thickness of the graphene/cellulose composite material coating is 8 μm.
In the step 5), the coating direction faces to the positive electrode side.
Example 5
Example 1 was repeated with the difference that:
step 1), fully mixing 25g of natural crystalline flake graphite and 100g of hydroxyethyl cellulose, and carrying out ball milling at room temperature for 5 hours to obtain composite graphene cellulose material powder;
step 2), dissolving 18g of sodium dodecyl benzene sulfonate in 715mL of water, dissolving 143g of the graphene cellulose material obtained in the step 1 in the water, and fully stirring to obtain graphene/cellulose composite slurry;
in the step 3), coating the mixed slurry coating roller in the step 2) on two sides of the polypropylene diaphragm base layer;
in the step 4), the thickness of the graphene/cellulose composite material coating on both sides of the diaphragm base layer is 2 μm.
Example 6
Example 1 was repeated with the difference that:
step 1), fully mixing 55g of natural crystalline flake graphite and 100g of hydroxypropyl methylcellulose, and performing ball milling at room temperature for 5 hours to obtain composite graphene cellulose material powder;
step 2) dissolving 20g of sodium hepatocholate in 500mL of water, dissolving 175g of the graphene cellulose material obtained in the step 1 in the water, and fully stirring to obtain graphene/cellulose composite slurry;
in the step 3), coating the mixed slurry coating roller in the step 2) on two sides of the polypropylene diaphragm base layer;
in the step 4), the thickness of the graphene/cellulose composite material coating on both sides of the diaphragm base layer is 5 μm.
Example 7
Example 1 was repeated with the difference that:
and 2) dissolving 25g of sodium dodecyl benzene sulfonate in 460mL of water, dissolving 160g of the graphene cellulose material obtained in the step (1) in the water, adding 1g of styrene butadiene rubber binder, and fully stirring to obtain the graphene/cellulose composite slurry.
Comparative example 1
Assembling the lithium ion battery:
and (3) placing a polypropylene diaphragm which is not coated with the graphene/cellulose composite material between the positive electrode and the negative electrode, adding 100 mu L of commercial lithium ion battery electrolyte, placing a reed, sealing by using a hydraulic sealing machine, preparing a button 2032 lithium ion battery, and carrying out a rate charge-discharge test and a thermal stability test.
Examples 1-7 and comparative example 1 were tested by the test methods described above to obtain cell performance parameters as shown in table 1.
Table 1 shows the performance parameters of the lithium ion batteries prepared in examples 1-7 and comparative example 1
Fig. 1 is a graph showing the first charge and discharge of the battery obtained in example 1. As can be seen from the figure, when the slurry is used in a lithium ion battery, the battery can be normally charged and discharged, and the battery has higher specific charge-discharge capacity.
FIG. 2 is a graph showing the change in rate charge/discharge specific capacity of the battery obtained in example 1. As can be seen from the figure, when the slurry is used in a lithium ion battery, the battery can still maintain higher specific discharge capacity during higher-rate charge and discharge.
The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiment. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (28)
1. The diaphragm containing the graphene/cellulose composite material is characterized by comprising a diaphragm base layer, a graphene/cellulose composite material layer on the surface of the diaphragm base layer facing to the positive electrode side and/or a graphene/cellulose composite material layer on the surface of the diaphragm base layer facing to the negative electrode side, wherein the graphene/cellulose composite material layer comprises graphene, cellulose and other auxiliary agents, one part of the cellulose is embedded between sheets of the graphene, and the other part of the cellulose is attached to the surface of the sheets of the graphene; the other auxiliary agent is at least one of a surfactant and a dispersant;
the mass ratio of the graphene to the cellulose is (20-50): 100; the mass ratio of the other auxiliary agents to the cellulose is (2-20) to 100;
the coating surface density of the graphene/cellulose composite material layer is 0.2-5g/m2；
The graphene/cellulose composite layer is obtained by a method comprising the following steps:
(a) mixing and grinding graphite and cellulose to prepare a mixed material;
(b) dissolving the mixed material obtained in the step (a) in water, adding other auxiliaries, and uniformly mixing to obtain mixed slurry of the graphene/cellulose composite material;
(c) coating the mixed slurry of step (b) on one or both surfaces of the separator base layer;
(d) and (c) drying the diaphragm coated with the mixed slurry in the step (c) to prepare a graphene/cellulose composite material layer attached to the surface of one side or two sides of the diaphragm base layer.
2. A membrane according to claim 1, characterized in that the thickness of the membrane is 5-100 μm.
3. The separator according to claim 1, wherein the separator base layer is a single-layer separator made of one material selected from the group consisting of polypropylene, polyethylene, polyvinylidene fluoride-hexafluoropropylene copolymer, polyester, glass fiber, aramid, and polyimide, or a multi-layer separator made of two or more materials.
4. The separator of claim 1, wherein the thickness of the separator base layer is 2-90 μ ι η.
5. The membrane according to claim 1, wherein the graphene/cellulose composite layer has a thickness of 0.1 to 10 μm.
6. The separator of claim 1, wherein the porosity of the separator base layer is 30% to 70%.
7. The separator according to claim 1, wherein in step (a), the grinding is carried out in a ball mill for 5-24 h; the grinding temperature is room temperature.
8. The membrane of claim 1, wherein in step (b), the mass ratio of the mixed material to water is (0.1-50): 100.
9. The separator of claim 1, wherein in step (c), the coating is selected from at least one of spray coating, knife coating, coating roll, coating brush.
10. The membrane of claim 1, wherein in step (d), the drying time is 1-24 h; the drying temperature is 30-80 ℃.
11. The membrane according to claim 1, wherein the graphite is selected from one or a mixture of natural crystalline flake graphite, crystalline graphite, microcrystalline graphite, synthetic graphite; the cellulose is selected from one or more of natural cellulose and derivatives thereof.
12. A diaphragm according to claim 1, wherein the graphite is selected from natural flake graphite; the cellulose is selected from methyl cellulose, ethyl cellulose, hydroxymethyl cellulose, cellulose acetate, hydroxyethyl cellulose or hypromellose.
13. The membrane according to claim 1, wherein the dispersant of the other auxiliary agents comprises one or more of castor oil, dodecyl sulfate, triethylhexyl phosphoric acid, methyl amyl alcohol, polyacrylamide, polyoxyethylene ether and oleamide;
the surfactant in the other auxiliary agents comprises one or more of dodecyl benzene sulfonate, dioctyl succinate sulfonate, fatty alcohol polyoxyethylene ether, oleyl alcohol polyoxyethylene ether, polyoxyethylene fatty acid ester, oleate and stearate.
14. The membrane according to claim 1, wherein the graphene/cellulose composite material layer further comprises a binder, and the mass ratio of the binder to the cellulose is (0-10): 100.
15. The separator of claim 14, wherein the binder comprises one or more of styrene-butadiene rubber, fluorinated rubber, polyvinyl alcohol, hydroxymethyl cellulose salt, polyacrylic acid, polyacrylate and its derivatives, polyacrylonitrile, acrylate-acrylonitrile copolymer, polymethyl methacrylate, dimethyl diallyl ammonium chloride, alginate, pectate, and antler glue salt.
16. The method for preparing a graphene/cellulose composite-containing separator according to any one of claims 1 to 15, wherein the method comprises the steps of:
(1) mixing and grinding graphite and cellulose to prepare a mixed material;
(2) dissolving the mixed material obtained in the step (1) in water, adding other auxiliaries, and uniformly mixing to obtain mixed slurry of the graphene/cellulose composite material;
(3) coating the mixed slurry of the step (2) on one side or two side surfaces of the diaphragm base layer;
(4) drying the diaphragm base layer coated with the mixed slurry in the step (3) to obtain the diaphragm containing the graphene/cellulose composite material;
wherein the other auxiliary agent is at least one selected from a surfactant and a dispersing agent.
17. The preparation method according to claim 16, wherein in the step (1), the grinding is carried out in a ball mill for 5 to 24 hours; the grinding temperature is room temperature.
18. The method according to claim 16, wherein in the step (2), the mass ratio of the mixed material to water is (0.1-50): 100.
19. The production method according to claim 16, wherein in the step (3), the coating is at least one selected from the group consisting of spray coating, blade coating, coating roll, and coating brush.
20. The method according to claim 16, wherein in the step (4), the drying time is 1 to 24 hours; the drying temperature is 30-80 ℃.
21. The preparation method according to claim 16, wherein the graphite is selected from one or a mixture of natural crystalline flake graphite, crystalline graphite, microcrystalline graphite, and synthetic graphite; the cellulose is selected from one or more of natural cellulose and derivatives thereof.
22. The method of claim 16, wherein the graphite is selected from natural flake graphite; the cellulose is selected from methyl cellulose, ethyl cellulose, hydroxymethyl cellulose, cellulose acetate, hydroxyethyl cellulose or hypromellose.
23. The preparation method of claim 16, wherein the dispersant in the other auxiliary agents comprises one or more of castor oil, dodecyl sulfate, triethylhexyl phosphoric acid, methyl amyl alcohol, polyacrylamide, polyoxyethylene ether and oleamide;
the surfactant in the other auxiliary agents comprises one or more of dodecyl benzene sulfonate, dioctyl succinate sulfonate, fatty alcohol polyoxyethylene ether, oleyl alcohol polyoxyethylene ether, polyoxyethylene fatty acid ester, oleate and stearate.
24. The preparation method of claim 16, wherein the graphene/cellulose composite material layer further comprises a binder, and the mass ratio of the binder to the cellulose is (0-10): 100.
25. The method of claim 24, wherein the binder comprises one or more of styrene-butadiene rubber, fluorinated rubber, polyvinyl alcohol, hydroxymethyl cellulose salt, polyacrylic acid, polyacrylate and its derivatives, polyacrylonitrile, acrylate-acrylonitrile copolymer, polymethyl methacrylate, dimethyl diallyl ammonium chloride, alginate, pectate, and antler glue salt.
26. A lithium ion battery, characterized in that the battery comprises a separator according to any one of claims 1 to 15.
27. The lithium ion battery of claim 26, wherein the lithium ion battery is at least one of a button cell, a stacked cell, and a wound cell.
28. The lithium ion battery of claim 26 or 27, wherein the outer package of the lithium ion battery is a soft plastic package or a steel shell package.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710392500.8A CN108933216B (en) | 2017-05-27 | 2017-05-27 | Diaphragm containing graphene/cellulose composite material and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710392500.8A CN108933216B (en) | 2017-05-27 | 2017-05-27 | Diaphragm containing graphene/cellulose composite material and preparation method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN108933216A CN108933216A (en) | 2018-12-04 |
| CN108933216B true CN108933216B (en) | 2020-10-30 |
Family
ID=64451456
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201710392500.8A Active CN108933216B (en) | 2017-05-27 | 2017-05-27 | Diaphragm containing graphene/cellulose composite material and preparation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN108933216B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111162231A (en) * | 2019-12-27 | 2020-05-15 | 清华大学 | Multifunctional diaphragm for lithium battery and preparation method and application thereof |
| CN112309609B (en) * | 2020-10-10 | 2021-06-04 | 山东华冠智能卡有限公司 | Water-based graphene conductive paste, preparation method thereof and RFID label |
| CN112952293B (en) * | 2021-01-29 | 2023-09-05 | 枣阳市格芯电子科技有限公司 | Explosion-proof low-internal-resistance lithium ion battery and preparation method thereof |
| WO2023245655A1 (en) * | 2022-06-24 | 2023-12-28 | 宁德时代新能源科技股份有限公司 | Separator, preparation method therefor, and secondary battery and electric device related thereto |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103427069A (en) * | 2012-05-19 | 2013-12-04 | 湖南省正源储能材料与器件研究所 | Lithium ion battery composite anode material and preparation thereof |
| CN103840125A (en) * | 2012-11-23 | 2014-06-04 | 中国科学院大连化学物理研究所 | Lithium-sulfur battery positive electrode structure and preparation method thereof |
| CN104538573A (en) * | 2014-12-30 | 2015-04-22 | 刘剑洪 | Diaphragm for lithium ion battery and preparation method of diaphragm |
| CN105895870A (en) * | 2016-04-06 | 2016-08-24 | 鸿纳（东莞）新材料科技有限公司 | High-concentration and high-purity graphene slurry and preparation method and application thereof |
| WO2016137147A1 (en) * | 2015-02-26 | 2016-09-01 | 한양대학교 산학협력단 | Separator membrane for secondary battery, method for manufacturing same, and lithium secondary battery comprising same |
| CN106299208A (en) * | 2016-10-12 | 2017-01-04 | 河北金力新能源科技股份有限公司 | A kind of preparation method of high temperature resistant low-resistivity lithium ion battery separator |
-
2017
- 2017-05-27 CN CN201710392500.8A patent/CN108933216B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103427069A (en) * | 2012-05-19 | 2013-12-04 | 湖南省正源储能材料与器件研究所 | Lithium ion battery composite anode material and preparation thereof |
| CN103840125A (en) * | 2012-11-23 | 2014-06-04 | 中国科学院大连化学物理研究所 | Lithium-sulfur battery positive electrode structure and preparation method thereof |
| CN104538573A (en) * | 2014-12-30 | 2015-04-22 | 刘剑洪 | Diaphragm for lithium ion battery and preparation method of diaphragm |
| WO2016137147A1 (en) * | 2015-02-26 | 2016-09-01 | 한양대학교 산학협력단 | Separator membrane for secondary battery, method for manufacturing same, and lithium secondary battery comprising same |
| CN105895870A (en) * | 2016-04-06 | 2016-08-24 | 鸿纳（东莞）新材料科技有限公司 | High-concentration and high-purity graphene slurry and preparation method and application thereof |
| CN106299208A (en) * | 2016-10-12 | 2017-01-04 | 河北金力新能源科技股份有限公司 | A kind of preparation method of high temperature resistant low-resistivity lithium ion battery separator |
Non-Patent Citations (2)
| Title |
|---|
| 机械剥离法制备石墨烯及其在石墨烯/陶瓷复合材料制备中的应用;江莞，范宇驰，刘霞，王连军;《中国材料进展》;20110131;第30卷(第1期);12-20 * |
| 石墨烯/纤维素复合材料的制备及应用;高玉荣，黄培，孙佩佩，吴敏，黄勇;《化学进展》;20160515(第5期);全文 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN108933216A (en) | 2018-12-04 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN110676420B (en) | Lithium ion battery's lithium diaphragm of mending | |
| CN108520985B (en) | Method for prolonging cycle life of zinc battery and application thereof | |
| CN105932206B (en) | Lithium-supplementing composite diaphragm, preparation method and application | |
| CN108933215B (en) | Graphene/cellulose composite material-containing slurry for battery, and preparation method and application thereof | |
| CN109004265B (en) | Solid electrolyte positive electrode and solid battery comprising same | |
| CN103413904B (en) | A kind of manufacture method of diaphragm for polymer lithium ion battery | |
| CN108933216B (en) | Diaphragm containing graphene/cellulose composite material and preparation method thereof | |
| CN107240718B (en) | Solid state battery and preparation method thereof | |
| CN113130838B (en) | Preparation method of multi-tab cell pole piece, multi-tab cell pole piece and multi-tab cell | |
| CN112467308B (en) | Diaphragm, preparation method thereof and lithium ion battery | |
| CN104966814B (en) | A kind of lithium anode of high security and preparation method thereof | |
| CN110993891A (en) | Silicon-containing negative plate, preparation method thereof and lithium ion battery | |
| CN212907803U (en) | Lithium ion battery with high-rate charge and discharge | |
| CN114597478A (en) | Electrochemical device and electronic device | |
| KR20090041074A (en) | Negative electrode for lithium rechargeable battery and lithium rechargeable battery adopting the same | |
| CN108933236B (en) | Lithium ion battery containing graphene/cellulose composite material and preparation method thereof | |
| CN112599719A (en) | Negative plate, preparation method of negative plate and battery | |
| CN113690545A (en) | Ceramic diaphragm, preparation method thereof and secondary battery | |
| CN110875476A (en) | Negative electrode for lithium secondary battery, method for preparing same, and lithium secondary battery | |
| CN112687839A (en) | Pole piece, preparation method thereof and lithium ion battery | |
| CN204885286U (en) | Lithium metal negative pole of high security | |
| CN113196524A (en) | Negative electrode material, negative electrode sheet, electrochemical device, and electronic device | |
| KR20020094530A (en) | Current collector coated with metal, electrodes comprising it, and lithium batteries comprising the electrodes | |
| CN114171849B (en) | Composite diaphragm with core-shell structure and preparation method thereof | |
| CN114883527A (en) | Multilayer negative plate, preparation method thereof and secondary battery |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |