CN115663119A - Flexible lithium ion battery cathode, preparation method thereof and flexible lithium ion battery - Google Patents
Flexible lithium ion battery cathode, preparation method thereof and flexible lithium ion battery Download PDFInfo
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- CN115663119A CN115663119A CN202211436413.5A CN202211436413A CN115663119A CN 115663119 A CN115663119 A CN 115663119A CN 202211436413 A CN202211436413 A CN 202211436413A CN 115663119 A CN115663119 A CN 115663119A
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- lithium ion
- ion battery
- ceramic fiber
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- sioc ceramic
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- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 title claims abstract description 77
- 229910001416 lithium ion Inorganic materials 0.000 title claims abstract description 77
- 238000002360 preparation method Methods 0.000 title claims abstract description 19
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- 239000000919 ceramic Substances 0.000 claims abstract description 77
- 239000006258 conductive agent Substances 0.000 claims abstract description 41
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 claims abstract description 31
- 229910052709 silver Inorganic materials 0.000 claims abstract description 30
- 239000004332 silver Substances 0.000 claims abstract description 30
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- 239000007774 positive electrode material Substances 0.000 claims description 8
- 239000002994 raw material Substances 0.000 claims description 8
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical group [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 7
- 239000004698 Polyethylene Substances 0.000 claims description 7
- 239000004743 Polypropylene Substances 0.000 claims description 7
- 239000011889 copper foil Substances 0.000 claims description 7
- 239000000463 material Substances 0.000 claims description 7
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- OIFBSDVPJOWBCH-UHFFFAOYSA-N Diethyl carbonate Chemical group CCOC(=O)OCC OIFBSDVPJOWBCH-UHFFFAOYSA-N 0.000 claims description 6
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- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims description 6
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 claims description 6
- IMNFDUFMRHMDMM-UHFFFAOYSA-N N-Heptane Chemical compound CCCCCCC IMNFDUFMRHMDMM-UHFFFAOYSA-N 0.000 claims description 6
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 6
- 239000002033 PVDF binder Substances 0.000 claims description 6
- 239000012298 atmosphere Substances 0.000 claims description 6
- 238000010041 electrostatic spinning Methods 0.000 claims description 6
- 229910052744 lithium Inorganic materials 0.000 claims description 6
- 229920003257 polycarbosilane Polymers 0.000 claims description 6
- 229920002981 polyvinylidene fluoride Polymers 0.000 claims description 6
- 229920000036 polyvinylpyrrolidone Polymers 0.000 claims description 6
- 239000001267 polyvinylpyrrolidone Substances 0.000 claims description 6
- 235000013855 polyvinylpyrrolidone Nutrition 0.000 claims description 6
- KXGFMDJXCMQABM-UHFFFAOYSA-N 2-methoxy-6-methylphenol Chemical compound [CH]OC1=CC=CC([CH])=C1O KXGFMDJXCMQABM-UHFFFAOYSA-N 0.000 claims description 5
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical group [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 5
- 229910052782 aluminium Inorganic materials 0.000 claims description 5
- 239000011888 foil Substances 0.000 claims description 5
- 239000005011 phenolic resin Substances 0.000 claims description 5
- 229920001568 phenolic resin Polymers 0.000 claims description 5
- 238000007789 sealing Methods 0.000 claims description 5
- 239000002904 solvent Substances 0.000 claims description 5
- 229910013870 LiPF 6 Inorganic materials 0.000 claims description 4
- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 claims description 4
- YLQBMQCUIZJEEH-UHFFFAOYSA-N tetrahydrofuran Natural products C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 claims description 4
- LZZYPRNAOMGNLH-UHFFFAOYSA-M Cetrimonium bromide Chemical compound [Br-].CCCCCCCCCCCCCCCC[N+](C)(C)C LZZYPRNAOMGNLH-UHFFFAOYSA-M 0.000 claims description 3
- 239000004372 Polyvinyl alcohol Substances 0.000 claims description 3
- NWGKJDSIEKMTRX-AAZCQSIUSA-N Sorbitan monooleate Chemical compound CCCCCCCC\C=C/CCCCCCCC(=O)OC[C@@H](O)[C@H]1OC[C@H](O)[C@H]1O NWGKJDSIEKMTRX-AAZCQSIUSA-N 0.000 claims description 3
- QHGJSLXSVXVKHZ-UHFFFAOYSA-N dilithium;dioxido(dioxo)manganese Chemical compound [Li+].[Li+].[O-][Mn]([O-])(=O)=O QHGJSLXSVXVKHZ-UHFFFAOYSA-N 0.000 claims description 3
- GVGUFUZHNYFZLC-UHFFFAOYSA-N dodecyl benzenesulfonate;sodium Chemical compound [Na].CCCCCCCCCCCCOS(=O)(=O)C1=CC=CC=C1 GVGUFUZHNYFZLC-UHFFFAOYSA-N 0.000 claims description 3
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 claims description 3
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical group C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 3
- 229910052759 nickel Inorganic materials 0.000 claims description 3
- 235000010482 polyoxyethylene sorbitan monooleate Nutrition 0.000 claims description 3
- 229920000053 polysorbate 80 Polymers 0.000 claims description 3
- 229920002451 polyvinyl alcohol Polymers 0.000 claims description 3
- 229940080264 sodium dodecylbenzenesulfonate Drugs 0.000 claims description 3
- NHTMVDHEPJAVLT-UHFFFAOYSA-N Isooctane Chemical compound CC(C)CC(C)(C)C NHTMVDHEPJAVLT-UHFFFAOYSA-N 0.000 claims description 2
- JVSWJIKNEAIKJW-UHFFFAOYSA-N dimethyl-hexane Natural products CCCCCC(C)C JVSWJIKNEAIKJW-UHFFFAOYSA-N 0.000 claims description 2
- 229920000548 poly(silane) polymer Polymers 0.000 claims description 2
- 239000000244 polyoxyethylene sorbitan monooleate Substances 0.000 claims description 2
- 229920001296 polysiloxane Polymers 0.000 claims description 2
- 229950004959 sorbitan oleate Drugs 0.000 claims 1
- 239000000843 powder Substances 0.000 abstract description 5
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- 230000000052 comparative effect Effects 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
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- 238000012360 testing method Methods 0.000 description 2
- 238000001291 vacuum drying Methods 0.000 description 2
- ZORQXIQZAOLNGE-UHFFFAOYSA-N 1,1-difluorocyclohexane Chemical compound FC1(F)CCCCC1 ZORQXIQZAOLNGE-UHFFFAOYSA-N 0.000 description 1
- 229910013872 LiPF Inorganic materials 0.000 description 1
- 101150058243 Lipf gene Proteins 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
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- 239000006229 carbon black Substances 0.000 description 1
- 239000000084 colloidal system Substances 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 239000011530 conductive current collector Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000001523 electrospinning Methods 0.000 description 1
- 238000005538 encapsulation Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 239000003292 glue Substances 0.000 description 1
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- 229940035049 sorbitan monooleate Drugs 0.000 description 1
Images
Classifications
-
- 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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- Battery Electrode And Active Subsutance (AREA)
- Secondary Cells (AREA)
Abstract
The invention provides a flexible lithium ion battery cathode, a preparation method thereof and a flexible lithium ion battery. The flexible lithium ion battery negative electrode comprises a negative electrode current collector, an SiOC ceramic fiber film and a silver conductive agent, wherein the SiOC ceramic fiber film is attached to one surface of the negative electrode current collector through the silver conductive agent and is formed by directionally arranging a plurality of SiOC ceramic fiber yarns; the flexible lithium ion battery cathode prepared by the invention has good flexibility, can be applied to various deformation products, and can not generate the phenomena of demoulding and powder falling after being bent for many times because the SiOC ceramic fiber film is in line contact with the cathode current collector, thereby improving the cycle stability of the flexible lithium ion battery cathode.
Description
Technical Field
The invention belongs to the technical field of lithium ion batteries, and particularly relates to a flexible lithium ion battery cathode, a preparation method thereof and a flexible lithium ion battery.
Background
With the continuous progress of science and technology and the continuous increase of people's demand, it is important to develop smaller, lighter and thinner lithium ion batteries. In recent years, in order to meet the requirements of bendable, implantable and wearable electronic products, flexible lithium ion batteries with different sizes, shapes and mechanical properties are researched and developed, so that the flexible lithium ion batteries have a very high application prospect.
At present, the flexible lithium ion battery has high requirements on the bending degree of positive and negative electrode materials, and patent CN114976208A discloses a wavy flexible lithium ion battery, which is flaky, wherein a positive electrode plate is aluminum foil plus lithium cobaltate, a negative electrode plate is copper foil plus graphite, a diaphragm material is PP/PE/PP, and electrolyte is LiPF 6 The battery is based on a lithium cobaltate/graphite lithium ion battery system, a battery core is formed by alternately stacking a single-sided negative electrode, a diaphragm, a double-sided positive electrode and a double-sided negative electrode, and after the battery is packaged, a flexible battery structure similar to a corrugated board is realized through a shaping process; however, when the negative active material is made into slurry and coated on the conductive current collector, the negative active material is not resistant to bending due to high brittleness and easy to demold and fall powder after being subjected to bending stress, so that the loss of the active material is caused, and the falling powder can pierce through the diaphragm to cause short circuit and bring potential safety hazards.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide a flexible lithium ion battery cathode, a preparation method thereof and a flexible lithium ion battery; the SiOC ceramic fiber film is used as an active material of the negative electrode of the flexible lithium ion battery, the silver conductive agent is used as a conductive agent and a binder of the negative electrode of the flexible lithium ion battery, and the SiOC ceramic fiber film is adhered to a negative current collector through the silver conductive agent to prepare the negative electrode of the flexible lithium ion battery.
In order to achieve the above object, a first aspect of the present invention provides a flexible lithium ion battery cathode, which adopts the following technical scheme:
the flexible lithium ion battery negative electrode comprises a negative electrode current collector, an SiOC ceramic fiber film and a silver conductive agent (silver conductive adhesive), wherein the SiOC ceramic fiber film is attached to one surface of the negative electrode current collector through the silver conductive agent, and the SiOC ceramic fiber film is formed by directionally arranging a plurality of SiOC ceramic fiber yarns.
In the above flexible lithium ion battery negative electrode, as a preferred embodiment, the SiOC ceramic fiber film is 90% to 99% (91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%) and the silver conductive agent is 1% to 10% (e.g., 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%) by mass percentage with respect to the total mass of the SiOC ceramic fiber film and the silver conductive agent.
The silver conductive agent is a liquid glue solution, is convenient to coat, can be cured at normal temperature, can effectively fix the SiOC ceramic fiber film and can also serve as a conductive agent, and no additional conductive agent is added; the SiOC ceramic fiber film is a Si-based negative electrode active material, has the advantage of high gram capacity, the gram capacity reaches more than 1400mAh/g, and also has the physical characteristics of high mechanical strength and high bending strength; by directionally arranging a plurality of SiOC ceramic fiber yarns to form the SiOC ceramic fiber membrane, the quality of a negative electrode active substance can be enhanced, an active material with higher capacity can be obtained, and the overall strength and flexibility of the material can be enhanced; the SiOC ceramic fiber film is adhered to the negative current collector by utilizing the silver conductive agent to prepare the flexible lithium ion battery negative electrode, the flexibility is good, the SiOC ceramic fiber film can be applied to various deformation products, and the SiOC ceramic fiber film is in line contact with the negative current collector, so that the demolding and powder falling phenomena can not occur after the SiOC ceramic fiber film is bent for many times, and the circulation stability of the flexible lithium ion battery negative electrode can be improved.
In the invention, the mass of the SiOC ceramic fiber film is limited to 90-99%, and the mass of the silver conductive agent is limited to 1-10%; the mass range is favorable for improving the capacity and the conductivity, and if the mass of the silver conductive agent is too much, the proportion of the negative active material is reduced, and the capacity is reduced; if the added mass of the silver conductive agent is too small, the conductive effect is poor, and the kinetics is affected.
In the above flexible lithium ion battery negative electrode, as a preferred embodiment, the negative electrode current collector is a copper foil, and has a thickness of 3 to 12 μm (e.g., 4 μm, 5 μm, 7 μm, 9 μm, 10 μm, 11 μm).
In the above flexible lithium ion battery negative electrode, as a preferred embodiment, the thickness of the SiOC ceramic fiber film is 50 μm to 150 μm (such as 55 μm, 70 μm, 80 μm, 90 μm, 100 μm, 120 μm); the SiOC ceramic filaments have a diameter of 100nm to 50 μm (e.g. 200nm, 500nm, 1 μm, 10 μm, 20 μm, 40 μm).
The second aspect of the present invention provides a preparation method of the above flexible lithium ion battery cathode, including: the method comprises the steps of taking SiC fiber yarns as raw materials, obtaining SiOC ceramic fiber yarns through sintering treatment, then arranging a plurality of SiOC ceramic fiber yarns in an oriented mode to form an SiOC ceramic fiber film, and then attaching the SiOC ceramic fiber film to one surface of a negative current collector through a silver conductive agent.
In the above method for manufacturing a flexible lithium ion battery negative electrode, as a preferred embodiment, the sintering treatment is performed in an air atmosphere, the sintering temperature is 150 ℃ to 400 ℃ (such as 180 ℃, 200 ℃, 250 ℃, 300 ℃, 320 ℃, 350 ℃, 380 ℃), and the sintering time is 5 to 24 hours (such as 8 hours, 10 hours, 12 hours, 15 hours, 18 hours, 20 hours, and 22 hours).
According to the invention, the SiC fiber yarn is used as a raw material and is sintered in an air atmosphere to obtain the SiOC ceramic fiber yarn, and if the sintering temperature is too low, the SiC fiber yarn cannot be completely oxidized into the SiOC ceramic fiber yarn; if the sintering temperature is too high, siO grows 2 This non-electroactive species, thereby reducing capacity.
In the above method for preparing a flexible lithium ion battery cathode, as a preferred embodiment, the SiC fiber filaments are prepared by taking a spinning solution as a raw material and performing an electrostatic spinning treatment; preferably, the spinning solution comprises, in mass percent: 70% -88% (such as 72%, 74%, 76%, 78%, 80%, 82%, 85%) of SiC fiber precursor, 2% -20% (such as 4%, 5%, 7%, 10%, 12%, 15%, 18%) of surfactant, and 10% -20% (such as 12%, 14%, 15%, 16%, 17%, 18%, 19%) of organic solvent.
In the above method for preparing a flexible lithium ion battery cathode, as a preferred embodiment, the SiC fiber precursor is selected from one or more of polycarbosilane, polysiloxane, polymethylsilane, and polysilane; the SiC fiber precursor is preferably polycarbosilane, and the molecular weight of the SiC fiber precursor is 1000-2000.
In the above method for preparing a flexible lithium ion battery negative electrode, as a preferred embodiment, the surfactant is one or more selected from polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), cetyltrimethylammonium bromide (CTAB), sodium Dodecylbenzenesulfonate (SDBS), polyoxyethylene sorbitan monooleate (Tween-80), and sorbitan monooleate (Span-80).
In the above method for preparing a flexible lithium ion battery negative electrode, as a preferred embodiment, the organic solvent is one or more selected from tetrahydrofuran, dimethylformamide, n-hexane, isooctane and n-heptane.
In the above method for preparing a flexible lithium ion battery negative electrode, as a preferred embodiment, in the electrospinning process, the spinning voltage is 5 to 30KV (e.g., 6KV, 8KV, 10KV, 15KV, 20KV, 25KV, 28 KV), and the spinning rate is 0.1 to 5mL/h (e.g., 0.2mL/h, 0.5mL/h, 1mL/h, 2mL/h, 3mL/h, 4mL/h, 4.5 mL/h).
According to the invention, the SiC fiber precursor and the surfactant are dispersed in the organic solvent, and the addition of the surfactant is beneficial to the uniform dispersion of the SiC fiber precursor in the organic solvent, so that a spinning solution with uniform components is obtained; the SiC fiber yarns are prepared by the spinning solution under the electrostatic spinning treatment.
A third aspect of the present invention provides a flexible lithium ion battery comprising: the flexible lithium ion battery comprises an electrode assembly, electrolyte and an outer packaging body, wherein the electrode assembly and the electrolyte are packaged by the outer packaging body to prepare the flexible lithium ion battery; the electrode assembly comprises a positive electrode, a diaphragm and a negative electrode which are sequentially stacked, and the negative electrode is the flexible lithium ion battery negative electrode or the flexible lithium ion battery negative electrode prepared by the preparation method.
In the above flexible lithium ion battery, as a preferred embodiment, the external packaging body is a thermoplastic tube, and the thermal shrinkage ratio of the thermoplastic tube is 1% to 500% (e.g. 5%, 50%, 80%, 100%, 150%, 200%, 300%, 400%).
According to the invention, the thermoplastic tube is used as the outer packaging body, the thermoplastic tube has high strength and good toughness, the electrode assembly body can be effectively isolated from the outside, and meanwhile, the thermoplastic tube has good ductility (flexibility) and can be bent and deformed; and only the copper foil provides a deformation supporting matrix in the flexible battery structure of the corrugated board, and the flexible lithium ion battery additionally adds the heat-shrinkable tube as the flexible matrix on the basis of taking the copper foil as the flexible supporting matrix, thereby further increasing the flexibility of the flexible lithium ion battery.
In the above flexible lithium ion battery, as a preferred embodiment, the positive electrode is a positive electrode current collector and an active material layer attached to one surface of the positive electrode current collector; the active material layer comprises the following components in percentage by mass: 95% -98% (e.g., 95.5%, 96%, 96.5%, 97%, 97.5%) of the positive electrode active material, 1% -3% (e.g., 1.2%, 1.5%, 1.8%, 2%, 2.5%, 2.7%) of the conductive agent, 1% -2% (e.g., 1.1%, 1.2%, 1.3%, 1.5%, 1.6%, 1.7%, 1.9%) of the binder; the active material layer is spaced from the SiOC ceramic fiber film by the separator.
Preferably, the mass of the active substance layer is 100-250mg/cm 2 (e.g., 120 mg/cm) 2 、150mg/cm 2 、180mg/cm 2 、200mg/cm 2 、220mg/cm 2 ) The compacted density is 3-4g/cm 3 (e.g., 3.2 g/cm) 3 、3.4g/cm 3 、3.5g/cm 3 、3.7g/cm 3 、3.9g/cm 3 )；
Preferably, the positive active material is selected from one of lithium cobaltate, lithium manganate, lithium iron phosphate and high nickel ternary material;
preferably, the conductive agent is conductive carbon black (super-p);
preferably, the binder is polyvinylidene fluoride (PVDF);
preferably, the positive electrode current collector is an aluminum foil with a thickness of 3-12 μm (e.g., 4 μm, 5 μm, 7 μm, 9 μm, 10 μm, 11 μm).
The method comprises the following steps of assembling an electrode assembly by laminating one surface of a positive current collector, which is attached with an active substance layer, with a diaphragm and one surface of a negative current collector, which is attached with an SiOC ceramic fiber film, wherein the active substance layer of a positive electrode and the SiOC ceramic fiber film of a negative electrode are separated by the diaphragm; and packaging the electrode assembly and the electrolyte into an outer packaging body to prepare the flexible lithium ion battery, wherein the flexible lithium ion battery has good flexibility and is suitable for various deformation products.
In the above flexible lithium ion battery, as a preferred embodiment, the material of the separator is polypropylene (PP) or Polyethylene (PE).
In the above flexible lithium ion battery, as a preferred embodiment, the electrolyte is 1mol/L LiPF 6 The solvent is diethyl carbonate (DEC) and Ethylene Carbonate (EC) in a volume ratio of 1.
In the above flexible lithium ion battery, as a preferred embodiment, the encapsulation process is: firstly, sheathing the electrode assembly into an external packaging body, then injecting electrolyte into the external packaging body, and then sealing two ends of the external packaging body by adopting phenolic resin.
Compared with the prior art, the invention has the following advantages:
(1) The SiOC ceramic fiber film is used as an active material of the negative electrode of the flexible lithium ion battery, the SiOC ceramic fiber film is used as a Si-based negative electrode material, the gram capacity is more than 1400mAh/g, the SiOC ceramic fiber film has high capacity, and the SiOC ceramic fiber film has high mechanical strength and bending strength and can be bent at 360 degrees.
(2) The silver conductive agent is used as the conductive agent and the binder of the negative electrode of the flexible lithium ion battery, and other conductive agents and binders are not required to be added; the SiOC ceramic fiber film is adhered to a negative current collector through the silver conductive agent to prepare the flexible lithium ion battery negative electrode, and the prepared negative electrode has good flexibility and can be applied to various deformation products.
(3) According to the invention, the SiOC ceramic fiber film is in line contact with the negative current collector, and the demoulding and powder falling phenomena cannot occur after the SiOC ceramic fiber film is bent for many times, so that the cycle stability of the negative electrode of the flexible lithium ion battery can be improved.
(4) The SiOC ceramic fiber film disclosed by the invention is simple in preparation process, low in cost and environment-friendly, and the prepared flexible battery is high in safety and adjustable in size, and can be applied to most of flexible electronic equipment on the market, such as electronic watches, VR (virtual reality) glasses, curved surface display screens and the like.
Drawings
FIG. 1 is a schematic structural view of an electrode assembly according to the present invention;
FIG. 2 is a schematic diagram of an outer package according to the present invention;
fig. 3 is a schematic structural diagram of the flexible lithium ion battery of the present invention.
Description of the drawings: 1. an electrode assembly; 11. a negative electrode; 111. a negative electrode current collector 112, a SiOC ceramic fiber film; 113. a silver conductive agent; 12. a diaphragm; 13. a positive electrode; 131. a positive current collector; 132. an active material layer; 2. and an outer packaging body.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. It should be understood by those skilled in the art that the examples are only for the understanding of the present invention and should not be construed as the specific limitations of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the description of the present invention, the terms "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, which are for convenience of description of the present invention only and do not require that the present invention must be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. The terms "connected," "connected," and "disposed" as used herein are intended to be broadly construed, and may include, for example, fixed connections and removable connections; can be directly connected or indirectly connected through intermediate components; the connection may be a wired electrical connection, a wireless electrical connection, or a wireless communication signal connection, and a person skilled in the art can understand the specific meaning of the above terms according to specific situations.
The embodiments of the present invention are implemented on the premise of the technical scheme of the present invention, and detailed embodiments and processes are given, but the scope of the present invention is not limited to the following embodiments, and the following embodiments do not indicate process parameters of specific conditions, and generally follow conventional conditions.
The endpoints of the ranges and any values disclosed in the present application are not limited to the precise range or value and should be understood to encompass values close to these ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual values, and between the individual values may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.
In the present invention, all numerical values relating to amounts of components are "parts by weight" throughout, unless otherwise specified and/or indicated. The process parameters for the specific conditions not noted in the following examples are generally in accordance with conventional conditions. The raw materials described in the following examples are all available from public commercial sources, and the silver conductive agent in the specific embodiment of the present invention is a compounded colloid, which is obtained by mixing a resin matrix, silver powder, an additive, and a solvent, and is commercially available.
The embodiment of the present invention provides a flexible lithium ion battery, and referring to fig. 1 to 3, the flexible lithium ion battery includes: an electrode assembly 1, an electrolyte, and an outer package 2; sheathing the electrode assembly 1 into the outer packaging body 2, injecting an electrolyte into the outer packaging body 2, and sealing two ends of the outer packaging body 2 by adopting phenolic resin to obtain a flexible lithium ion battery; the electrode assembly 1 includes a negative electrode 11, a separator 12, and a positive electrode 13 stacked in this order; the negative electrode 11 includes a negative electrode collector 111 and a SiOC ceramic fiber film 112 adhered to one surface of the negative electrode collector 111 by a silver conductive agent 113, the positive electrode 13 includes a positive electrode collector 131 and an active material layer 132 adhered to one surface of the positive electrode collector 131, the SiOC ceramic fiber film 112 is spaced from the active material layer 132 by a separator 12, that is, the surface of the negative electrode collector 111 to which the SiOC ceramic fiber film 112 is adhered is disposed opposite to the surface of the positive electrode collector 131 to which the active material layer 132 is adhered.
Further, the SiOC ceramic fiber film is 90-99% and the silver conductive agent is 1-10% by mass relative to the total mass of the SiOC ceramic fiber film and the silver conductive agent.
Further, the thickness of the SiOC ceramic fiber film 112 is 50 μm to 150 μm; forming the SiOC ceramic fiber film 112 by arranging a plurality of SiOC ceramic fiber filaments in an oriented manner, wherein each SiOC ceramic fiber filament has a diameter of 100nm to 50 μm;
further, the negative current collector 111 is a copper foil, and the thickness is 3-12 μm;
further, the material of the separator 12 is polypropylene (PP) or Polyethylene (PE);
further, the positive current collector 113 is an aluminum foil, and the thickness is 3-12 μm;
further, the active material layer 132 includes, in mass percent: 95% -98% of positive electrode active material, 1% -3% of conductive agent and 1% -2% of binder;
further, the mass of the active material layer 132 is 100 to 250mg/cm 2 The compacted density is 3-4g/cm 3 ；
Further, the positive active material is selected from one of lithium cobaltate, lithium manganate, lithium iron phosphate and high nickel ternary material; the conductive agent is conductive carbon black (super-p); the binder is polyvinylidene fluoride (PVDF);
further, the outer package 2 is a thermoplastic tube with a thermal shrinkage ratio of 1% to 500%.
Further, the electrolyte is 1mol/L LiPF 6 The solvent is DEC and EC with the volume ratio of 1.
The specific embodiment of the invention provides a preparation method of a flexible lithium ion battery, which comprises the following steps:
(1) Preparation of SiOC ceramic fiber: taking a spinning solution as a raw material, preparing SiC fiber yarns by electrostatic spinning with the spinning voltage of 5-30Kv and the spinning speed of 0.1-5mL/h, and sintering the SiC fiber yarns at 150-400 ℃ for 5-24h in an air atmosphere to prepare SiOC ceramic fiber yarns; wherein, by mass percent, the spinning solution comprises: 70-88% of SiC fiber precursor, 2-20% of surfactant and 10-20% of organic solvent.
(2) Preparation of negative electrode 11: arranging a plurality of SiOC ceramic fiber filaments in an oriented manner to form an SiOC ceramic fiber film 112, and then attaching the SiOC ceramic fiber film 112 to one surface of a negative electrode current collector 111 through a silver conductive agent 113 to prepare a negative electrode 11;
(3) Preparation of the positive electrode 13: dissolving a positive electrode active material, a conductive agent and a binder in NMP according to a certain mass ratio to prepare slurry, uniformly coating the slurry on a positive electrode current collector 131, and performing vacuum drying and rolling treatment to prepare a positive electrode 13;
(4) Preparation of electrode assembly 1: the negative electrode 11 (with the surface to which the SiOC ceramic fiber film 112 is adhered facing upward), the separator 12, and the positive electrode 13 (with the surface to which the active material layer 132 is adhered facing downward) were sequentially stacked to obtain an electrode assembly 1;
(5) Packaging treatment: sheathing the electrode assembly 1 into the outer packaging body 2, injecting electrolyte into the outer packaging body 2, and sealing two ends of the outer packaging body 2 by adopting phenolic resin to obtain the flexible lithium ion battery.
The present invention will be described in further detail with reference to specific examples.
Embodiment 1 a method for preparing a flexible lithium ion battery, comprising:
(1) Preparation of SiOC ceramic fiber: dissolving polycarbosilane (with a molecular weight of 1500) and polyvinylpyrrolidone (PVP) in tetrahydrofuran to obtain a spinning solution, wherein the spinning solution comprises the following components in percentage by mass: 80% polycarbosilane, 3.5% polyvinylpyrrolidone and the balance tetrahydrofuran; then injecting the spinning solution into a micro pump for electrostatic spinning, wherein the spinning voltage is 10KV, the spinning speed is 0.5mL/h, a plurality of SiC fiber yarns with the diameter of 15-30 mu m are obtained, and then sintering the SiC fiber yarns at 240 ℃ for 5h in an air atmosphere to prepare SiOC ceramic fiber yarns;
(2) Preparing a negative electrode: a plurality of SiOC ceramic fiber filaments are directionally arranged to form an SiOC ceramic fiber film with the thickness of 100 mu m, and then the SiOC ceramic fiber film is attached to a copper foil with the thickness of 6 mu m through a silver conductive agent to prepare a negative electrode, wherein the mass ratio of the SiOC ceramic fiber film to the silver conductive agent is 85;
(3) Preparation of the positive electrode: lithium cobaltate, carbon black and PVDF are mixed according to the mass ratio of 97:1.5 dissolving the raw materials in NMP to prepare slurry, uniformly coating the slurry on an aluminum foil with the thickness of 9 mu m, and performing vacuum drying and rolling treatment to obtain an active material layer with the mass of 180mg/cm 2 And a compacted density of 3.5g/cm 3 A positive electrode;
(4) Preparing an electrode assembly: an electrode assembly was obtained by stacking a negative electrode (with the surface to which the SiOC ceramic fiber film was adhered facing upward), a separator PE, and a positive electrode (with the surface to which the active material layer was adhered facing downward) in this order;
(5) Packaging treatment: sheathing the electrode assembly into a thermoplastic tube with the diameter of 10mm, the length of 22cm and the heat shrinkage ratio of 50%, and then injecting 1mol/L lithium hexafluorophosphate (LiPF) 6 ) The solvent is Ethylene Carbonate (EC): ethyl carbonate (DMC) =1:1, and then sealing the two ends of the thermoplastic tube by adopting phenolic resin to obtain the flexible lithium ion battery with the capacity of 800 mAh.
Comparative example 1
In comparative example 1, the SiC fiber filament was sintered at 500 ℃ for 5 hours in an air atmosphere to prepare a SiOC ceramic fiber filament, and the rest was the same as in example 1.
And (4) performance testing:
the flexible lithium ion batteries prepared in example 1 and comparative example 1 were subjected to initial discharge specific volume and cycle performance tests at 0.5C under room temperature conditions (25 ℃ ± 1) at a voltage of 3.0 to 4.3V under 50 times of unbending and manual bending, respectively, and the test results are shown in table 1.
TABLE 1
The above description is intended to be illustrative of the preferred embodiment of the present invention and should not be taken as limiting the invention, but rather, the invention is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.
Claims (10)
1. The flexible lithium ion battery negative electrode is characterized by comprising a negative electrode current collector, an SiOC ceramic fiber film and a silver conductive agent, wherein the SiOC ceramic fiber film is attached to one surface of the negative electrode current collector through the silver conductive agent, and the SiOC ceramic fiber film is formed by directionally arranging a plurality of SiOC ceramic fiber yarns.
2. The flexible lithium ion battery negative electrode of claim 1, wherein the SiOC ceramic fiber film is 90-99% and the silver conductive agent is 1-10% by mass, relative to the total mass of the SiOC ceramic fiber film and the silver conductive agent; and/or the negative current collector is a copper foil, and the thickness of the negative current collector is 3-12 mu m; and/or the thickness of the SiOC ceramic fiber film is 50-150 μm; the diameter of the SiOC ceramic fiber filament is 100nm-50 mu m.
3. The preparation method of the flexible lithium ion battery negative electrode as claimed in claim 1 or 2, characterized by comprising: the method comprises the steps of taking SiC fiber yarns as raw materials, obtaining SiOC ceramic fiber yarns through sintering treatment, then arranging a plurality of SiOC ceramic fiber yarns in an oriented mode to form an SiOC ceramic fiber film, and then attaching the SiOC ceramic fiber film to one surface of a negative current collector through a silver conductive agent.
4. The method for preparing the negative electrode of the flexible lithium ion battery according to claim 3, wherein the sintering treatment is carried out in an air atmosphere, the sintering temperature is 150-400 ℃, and the sintering time is 5-24h.
5. The preparation method of the flexible lithium ion battery cathode according to claim 3 or 4, wherein the SiC fiber yarn is prepared by taking a spinning solution as a raw material through electrostatic spinning treatment; the spinning solution comprises the following components in percentage by mass: 70-88% of SiC fiber precursor, 2-20% of surfactant and 10-20% of organic solvent.
6. The preparation method of the flexible lithium ion battery cathode according to claim 5, wherein the SiC fiber precursor is selected from one or more of polycarbosilane, polysiloxane, polymethylsilane and polysilane; the SiC fiber precursor is preferably polycarbosilane, and the molecular weight of the SiC fiber precursor is 1000-2000; and/or the surfactant is selected from one or more of polyvinylpyrrolidone, polyvinyl alcohol, cetyl trimethyl ammonium bromide, sodium dodecyl benzene sulfonate, polyoxyethylene sorbitan monooleate and sorbitan oleate (Span-80); and/or the organic solvent is selected from one or more of tetrahydrofuran, dimethylformamide, n-hexane, isooctane and n-heptane; and/or in the electrostatic spinning treatment, the spinning voltage is 5-30KV, and the spinning speed is 0.1-5mL/h.
7. A flexible lithium ion battery, comprising: the electrode assembly and the electrolyte are packaged by the outer packaging body to prepare the flexible lithium ion battery; the electrode assembly comprises a positive electrode, a diaphragm and a negative electrode which are sequentially stacked, wherein the negative electrode is the flexible lithium ion battery negative electrode in claim 1 or 2 or the flexible lithium ion battery negative electrode prepared by the preparation method in any one of claims 3 to 6.
8. The flexible lithium ion battery of claim 7, wherein the outer packaging body is a thermoplastic tube having a thermal shrinkage ratio of 1% -500%.
9. The flexible lithium ion battery according to claim 7 or 8, wherein the positive electrode is a positive electrode current collector and an active material layer attached to one surface of the positive electrode current collector; the active material layer comprises the following components in percentage by mass: 95% -98% of positive electrode active material, 1% -3% of conductive agent and 1% -2% of binder; the active material layer is spaced from the SiOC ceramic fiber film by the separator; and/or the mass of the active material layer is 100-250mg/cm 2 The compacted density is 3-4g/cm 3 (ii) a And/or the positive active material is selected from one of lithium cobaltate, lithium manganate, lithium iron phosphate and high nickel ternary material; the conductive agent is conductive carbon black; the binder is polyvinylidene fluoride; the positive current collector is aluminum foil, and the thickness of the positive current collector is 3-12 mu m.
10. The flexible lithium ion battery according to any one of claims 7-9, wherein the separator is made of polypropylene or polyethylene; the electrolyte is 1mol/L LiPF 6 The solvent is diethyl carbonate and ethylene carbonate with the volume ratio of 1; and/or the packaging treatment comprises the steps of firstly sleeving the electrode assembly into the outer packaging body, then injecting electrolyte into the outer packaging body, and then sealing the two ends of the outer packaging body by adopting phenolic resin.
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| CN107464916A (en) * | 2017-08-31 | 2017-12-12 | 柔电（武汉）科技有限公司 | A kind of laminated type flexible electrical pole piece and preparation method thereof |
| CN115172750A (en) * | 2022-06-14 | 2022-10-11 | 复旦大学 | Flexible fibrous braided lithium ion battery cathode and preparation and application thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN107464916A (en) * | 2017-08-31 | 2017-12-12 | 柔电（武汉）科技有限公司 | A kind of laminated type flexible electrical pole piece and preparation method thereof |
| CN115172750A (en) * | 2022-06-14 | 2022-10-11 | 复旦大学 | Flexible fibrous braided lithium ion battery cathode and preparation and application thereof |
Non-Patent Citations (1)
| Title |
|---|
| SHAKIR BIN MUJIB等: ""Self-supporting carbon-rich SiOC ceramic electrodes for lithium-ion batteries and aqueoussupercapacitors"", 《RSC ADVANCES》, vol. 11, no. 56, pages 35440 - 35454 * |
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