CN115663119B - Flexible lithium ion battery negative electrode, preparation method thereof and flexible lithium ion battery - Google Patents
Flexible lithium ion battery negative electrode, preparation method thereof and flexible lithium ion battery Download PDFInfo
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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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- 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
- 238000000034 method Methods 0.000 claims abstract description 18
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- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical compound C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 claims description 8
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- 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
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- KMTRUDSVKNLOMY-UHFFFAOYSA-N Ethylene carbonate Chemical compound O=C1OCCO1 KMTRUDSVKNLOMY-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
- 239000011230 binding agent Substances 0.000 claims description 6
- 238000010041 electrostatic spinning Methods 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
- 239000007774 positive electrode material Substances 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
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims description 5
- 239000000853 adhesive Substances 0.000 claims description 5
- 230000001070 adhesive effect Effects 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
- 229910052744 lithium Inorganic materials 0.000 claims description 5
- 239000000463 material Substances 0.000 claims description 5
- 239000005011 phenolic resin Substances 0.000 claims description 5
- 229920001568 phenolic resin Polymers 0.000 claims description 5
- 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
- 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
- WRIDQFICGBMAFQ-UHFFFAOYSA-N (E)-8-Octadecenoic acid Natural products CCCCCCCCCC=CCCCCCCC(O)=O WRIDQFICGBMAFQ-UHFFFAOYSA-N 0.000 claims description 2
- LQJBNNIYVWPHFW-UHFFFAOYSA-N 20:1omega9c fatty acid Natural products CCCCCCCCCCC=CCCCCCCCC(O)=O LQJBNNIYVWPHFW-UHFFFAOYSA-N 0.000 claims description 2
- QSBYPNXLFMSGKH-UHFFFAOYSA-N 9-Heptadecensaeure Natural products CCCCCCCC=CCCCCCCCC(O)=O QSBYPNXLFMSGKH-UHFFFAOYSA-N 0.000 claims description 2
- NHTMVDHEPJAVLT-UHFFFAOYSA-N Isooctane Chemical compound CC(C)CC(C)(C)C NHTMVDHEPJAVLT-UHFFFAOYSA-N 0.000 claims description 2
- 101150058243 Lipf gene Proteins 0.000 claims description 2
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- ZQPPMHVWECSIRJ-UHFFFAOYSA-N Oleic acid Natural products CCCCCCCCC=CCCCCCCCC(O)=O ZQPPMHVWECSIRJ-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
- QXJSBBXBKPUZAA-UHFFFAOYSA-N isooleic acid Natural products CCCCCCCC=CCCCCCCCCC(O)=O QXJSBBXBKPUZAA-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
- 239000008393 encapsulating agent Substances 0.000 claims 1
- 238000005452 bending Methods 0.000 abstract description 8
- 239000000843 powder Substances 0.000 abstract description 4
- 230000001351 cycling effect Effects 0.000 abstract description 2
- 239000006183 anode active material Substances 0.000 description 5
- 239000002002 slurry Substances 0.000 description 5
- 239000011159 matrix material Substances 0.000 description 4
- 229910013870 LiPF 6 Inorganic materials 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 239000002904 solvent Substances 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 239000010406 cathode material Substances 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000010439 graphite Substances 0.000 description 2
- 229910002804 graphite Inorganic materials 0.000 description 2
- 238000011056 performance test Methods 0.000 description 2
- 238000005096 rolling process Methods 0.000 description 2
- 238000001291 vacuum drying Methods 0.000 description 2
- 229910013872 LiPF Inorganic materials 0.000 description 1
- 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 description 1
- 239000013543 active substance Substances 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 239000010405 anode material Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
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- 239000000084 colloidal system Substances 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000011530 conductive current collector Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
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- 239000006185 dispersion Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
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- 239000003292 glue Substances 0.000 description 1
- 238000003475 lamination Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229910000625 lithium cobalt oxide Inorganic materials 0.000 description 1
- BFZPBUKRYWOWDV-UHFFFAOYSA-N lithium;oxido(oxo)cobalt Chemical compound [Li+].[O-][Co]=O BFZPBUKRYWOWDV-UHFFFAOYSA-N 0.000 description 1
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- 239000011871 silicon-based negative electrode active material Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
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
Landscapes
- Battery Electrode And Active Subsutance (AREA)
- Secondary Cells (AREA)
Abstract
The invention provides a flexible lithium ion battery negative electrode, a preparation method thereof and a flexible lithium ion battery. The flexible lithium ion battery cathode comprises a cathode 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 cathode current collector through the silver conductive agent, and the SiOC ceramic fiber film is formed by directional arrangement of a plurality of SiOC ceramic fiber filaments; the flexible lithium ion battery negative electrode prepared by the method has good flexibility, can be applied to various deformation products, and can not generate the phenomenon of demolding and powder falling after repeated bending due to the fact that the SiOC ceramic fiber film is in line contact with the negative electrode current collector, so that the cycling stability of the flexible lithium ion battery negative electrode can be improved.
Description
Technical Field
The invention belongs to the technical field of lithium ion batteries, and particularly relates to a flexible lithium ion battery negative electrode, a preparation method thereof and a flexible lithium ion battery.
Background
With the continuous progress of technology and the continuous growth of demands of people, the development of smaller, lighter and thinner lithium ion batteries is particularly important. In recent years, in order to meet the requirements of flexible, implantable and wearable electronic products, flexible lithium ion batteries with different sizes, shapes and mechanical properties are developed, and the flexible lithium ion batteries have a very high application prospect.
At present, the flexible lithium ion battery has high requirement on the bending degree of anode and cathode materials, patent CN114976208A discloses a wavy flexible lithium ion battery, the battery is in a flake shape, an anode plate is aluminum foil and lithium cobaltate, a cathode plate is copper foil and graphite, a diaphragm material is PP/PE/PP, and electrolyte is LiPF 6 Upper, upperThe battery is based on a lithium cobalt oxide/graphite lithium ion battery system, wherein 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 anode active material is made into a slurry and coated on the conductive current collector, since the anode active material itself is brittle, not resistant to bending, powder is easily removed from the mold after receiving bending stress, thereby causing loss of the active material, and the dropped powder may also pierce through the separator, causing a short circuit, bringing a safety hazard.
Disclosure of Invention
Aiming at the defects and shortcomings existing 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; according to the invention, the SiOC ceramic fiber film is used as an active material of the flexible lithium ion battery negative electrode, the silver conductive agent is used as a conductive agent and a binder of the flexible lithium ion battery negative electrode, and the SiOC ceramic fiber film is adhered to the negative electrode current collector through the silver conductive agent to prepare the flexible lithium ion battery negative electrode.
In order to achieve the above object, the first aspect of the present invention provides a flexible lithium ion battery anode, which adopts the following technical scheme:
a flexible lithium ion battery cathode comprises a cathode 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 cathode current collector through the silver conductive agent, and the SiOC ceramic fiber film is formed by directional arrangement of a plurality of SiOC ceramic fiber filaments.
In the above flexible lithium ion battery anode, as a preferred embodiment, the SiOC ceramic fiber film is 90% -99% (91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%) and the silver conductive agent is 1% -10% (e.g., 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%) by mass relative to the total mass of the SiOC ceramic fiber film and the silver conductive agent.
The silver conductive agent is liquid glue solution, is convenient for coating, can be cured at normal temperature, can effectively fix the SiOC ceramic fiber film and can also serve as a conductive agent, and the addition of the additional conductive agent is not needed; the SiOC ceramic fiber film is a Si-based negative electrode active material, has the advantage of high gram capacity which is more than 1400mAh/g, and has the physical characteristics of high mechanical strength and high bending strength; by arranging a plurality of SiOC ceramic fiber filaments in an oriented manner to form the SiOC ceramic fiber membrane, the quality of the anode active material 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 electrode current collector by utilizing the silver conductive agent to prepare the flexible lithium ion battery negative electrode, the flexible lithium ion battery negative electrode has good flexibility, and can be applied to various deformation products.
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 conductivity is improved while the capacity is improved in the mass range, and if the mass of the silver conductive agent is excessive, the duty ratio of the anode 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 dynamics are affected.
In the above flexible lithium ion battery anode, as a preferred embodiment, the anode current collector is copper foil with a thickness of 3-12 μm (such as 4 μm, 5 μm, 7 μm, 9 μm, 10 μm, 11 μm).
In the above flexible lithium ion battery anode, as a preferred embodiment, the SiOC ceramic fiber film has a thickness of 50 μm to 150 μm (such as 55 μm, 70 μm, 80 μm, 90 μm, 100 μm, 120 μm); the SiOC ceramic fiber 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 invention provides a preparation method of the flexible lithium ion battery anode, comprising the following steps: siOC ceramic fiber filaments are obtained by sintering SiC fiber filaments serving as raw materials, then a plurality of SiOC ceramic fiber filaments are directionally arranged to form an SiOC ceramic fiber film, and then the SiOC ceramic fiber film is attached to one surface of a negative electrode current collector through a silver conductive agent.
In the above method for preparing a negative electrode of a flexible lithium ion battery, as a preferred embodiment, the sintering treatment is performed under an air atmosphere, the sintering temperature is 150 ℃ -400 ℃ (for example 180 ℃, 200 ℃, 250 ℃, 300 ℃, 320 ℃, 350 ℃, 380 ℃), and the sintering time is 5-24 hours (for example 8 hours, 10 hours, 12 hours, 15 hours, 18 hours, 20 hours, 22 hours).
According to the invention, siC fiber yarns are used as raw materials and sintered in an air atmosphere to obtain SiOC ceramic fiber yarns, and if the sintering temperature is too low, the SiC fiber yarns cannot be completely oxidized into SiOC ceramic fiber yarns; if the sintering temperature is too high, siO grows 2 Such non-electroactive species, thereby reducing capacity.
In the preparation method of the flexible lithium ion battery cathode, as a preferred embodiment, the SiC fiber yarn is prepared by using a spinning solution as a raw material through 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 negative electrode of a flexible lithium ion battery, as a preferred embodiment, the SiC fiber precursor is one or more selected from polycarbosilane, polysiloxane, polymethylsilane, polysilane; the SiC fiber precursor is preferably polycarbosilane with a molecular weight of 1000-2000.
In the above method for preparing a flexible lithium ion battery negative electrode, as a preferred embodiment, the surfactant is selected from one or more of polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), cetyltrimethylammonium bromide (CTAB), sodium Dodecyl Benzene Sulfonate (SDBS), polyoxyethylene sorbitan monooleate (Tween-80), and sorbitan oleic acid ester (Span-80).
In the above method for preparing a negative electrode of a flexible lithium ion battery, 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 anode, as a preferred embodiment, in the electrospinning process, the spinning voltage is 5-30KV (e.g., 6KV, 8KV, 10KV, 15KV, 20KV, 25KV, 28 KV), and the spinning rate is 0.1-5mL/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 more uniform dispersion of the SiC fiber precursor in the organic solvent, so that the spinning solution with uniform components is obtained; the SiC fiber yarn is prepared by carrying out electrostatic spinning treatment on the spinning solution.
A third aspect of the present invention provides a flexible lithium ion battery comprising: the flexible lithium ion battery is prepared by packaging the electrode assembly, the electrolyte and the outer packaging body through the outer packaging body; the electrode assembly comprises a positive electrode, a diaphragm and a negative electrode which are sequentially stacked, wherein the negative electrode is the negative electrode of the flexible lithium ion battery or the negative electrode of the flexible lithium ion battery prepared by the preparation method.
In the above flexible lithium ion battery, as a preferred embodiment, the outer package is a thermoplastic tube, and the heat shrinkage ratio of the thermoplastic tube is 1% -500% (e.g., 5%, 50%, 80%, 100%, 150%, 200%, 300%, 400%).
The thermoplastic pipe is used as the outer packaging body, the thermoplastic pipe has high strength and good toughness, the electrode assembly can be effectively isolated from the outside, and meanwhile, the thermoplastic pipe has good ductility (flexibility) and can be bent and deformed; only the copper foil provides a deformation supporting matrix in the flexible battery structure of the corrugated board, and the flexible lithium ion battery provided by the invention has the advantages that the heat shrinkage tube is additionally added as the flexible matrix on the basis of taking the copper foil as the flexible supporting matrix, so that the flexibility of the flexible lithium ion battery is further increased.
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% (such as 95.5%, 96%, 96.5%, 97%, 97.5%) of positive electrode active material, 1% -3% (such as 1.2%, 1.5%, 1.8%, 2%, 2.5%, 2.7%) of conductive agent, 1% -2% (such as 1.1%, 1.2%, 1.3%, 1.5%, 1.6%, 1.7%, 1.9%) of binder; the active material layer is spaced from the SiOC ceramic fiber film by the separator.
Preferably, the mass of the active material 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 electrode active material is selected from one of lithium cobaltate, lithium manganate, lithium iron phosphate and high nickel ternary materials;
preferably, the conductive agent is conductive carbon black (super-p);
preferably, the binder is polyvinylidene fluoride (PVDF);
preferably, the positive electrode current collector is aluminum foil having a thickness of 3-12 μm (e.g., 4 μm, 5 μm, 7 μm, 9 μm, 10 μm, 11 μm).
The invention assembles the positive electrode current collector with one surface of active material layer and one surface of diaphragm and negative electrode current collector with SiOC ceramic fiber film through lamination to form electrode assembly, the active material layer of positive electrode and SiOC ceramic fiber film of negative electrode are separated by 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 separator is made of polypropylene (PP) or Polyethylene (PE).
In the flexible lithium ion battery, as a preferred embodiment, the electrolyte is 1mol/L LiPF 6 The solution comprises diethyl carbonate (DEC) and Ethylene Carbonate (EC) in a volume ratio of 1:1.
In the above flexible lithium ion battery, as a preferred embodiment, the encapsulation process is: firstly, sleeving an electrode assembly into an outer packaging body, then injecting electrolyte into the outer packaging body, and then adopting phenolic resin to seal the two ends of the outer packaging body.
Compared with the prior art, the invention has the following advantages:
(1) According to the invention, the SiOC ceramic fiber film is used as an active material of the flexible lithium ion battery cathode, the SiOC ceramic fiber film is used as a Si-based cathode material, the gram capacity is more than 1400mAh/g, and the SiOC ceramic fiber film has very high capacity, very high mechanical strength and bending strength, and can be bent at 360 degrees.
(2) According to the invention, the silver conductive agent is used as the conductive agent and the adhesive of the flexible lithium ion battery cathode, and the addition of other conductive agents and adhesives is not needed; the SiOC ceramic fiber film is adhered to the negative electrode 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 electrode current collector, and the phenomenon of demolding and powder falling can not occur after repeated bending, so that the cycling stability of the negative electrode of the flexible lithium ion battery can be improved.
(4) The SiOC ceramic fiber film has the advantages of simple preparation process, low cost and environmental friendliness, and the prepared flexible battery has high safety and adjustable size, and can be applied to most flexible electronic equipment on the market, such as electronic watches, VR glasses, curved display screens and the like.
Drawings
FIG. 1 is a schematic 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 a 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, an SiOC ceramic fiber film; 113. a silver conductive agent; 12. a diaphragm; 13. a positive electrode; 131. a positive electrode current collector; 132. an active material layer; 2. and an outer package.
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 in the following in conjunction with the embodiments of the present invention. It will be apparent to those skilled in the art that the examples are merely to aid in understanding the invention and are not to be construed as a specific limitation thereof. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
In the description of the present invention, the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", etc. refer to the orientation or positional relationship based on that shown in the drawings, merely for convenience of description of the present invention 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 "coupled," "connected," and "configured" as used herein are to be construed broadly and may be, for example, fixedly connected or detachably connected; can be directly connected or indirectly connected through an intermediate component; either a wired electrical connection, a radio connection or a wireless communication signal connection, the specific meaning of which terms will be understood by those of ordinary skill in the art as the case may be.
The examples of the present invention are implemented on the premise of the technical scheme of the present invention, and detailed implementation modes and processes are given, but the protection scope of the present invention is not limited to the following examples, in which the process parameters of specific conditions are not noted, and generally according to conventional conditions.
The endpoints of the ranges and any values disclosed in the present invention are not limited to the precise range or value, and the range or value should be understood to include values close to the range or value. For numerical ranges, one or more new numerical ranges may be obtained in combination with each other between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point values, and are to be considered as specifically disclosed in the present invention.
In the present invention, all values relating to the amounts of the components are "parts by weight" throughout unless specified and/or indicated otherwise. The process parameters for the specific conditions not noted in the examples below are generally as usual. The raw materials described in the following examples are all commercially available from public sources, and the silver conductive agent in the embodiment of the present invention is a compound colloid, which is obtained by mixing a resin matrix, silver powder, additives, and a solvent, and is commercially available.
Embodiments of the present invention provide a flexible lithium ion battery, referring to fig. 1 to 3, the flexible lithium ion battery includes: an electrode assembly 1, an electrolyte, and an outer package 2; sleeving the electrode assembly 1 into the outer packaging body 2, then injecting electrolyte into the outer packaging body 2, and then adopting phenolic resin to end-cap two ends of the outer packaging body 2 to obtain a flexible lithium ion battery; the electrode assembly 1 includes a negative electrode 11, a separator 12, and a positive electrode 13, which are stacked in this order; the negative electrode 11 includes a negative electrode current collector 111 and a SiOC ceramic fiber film 112 adhered to one surface of the negative electrode current collector 111 through a silver conductive agent 113, and the positive electrode 13 includes a positive electrode current collector 131 and an active material layer 132 adhered to one surface of the positive electrode current collector 131, the SiOC ceramic fiber film 112 being spaced apart from the active material layer 132 by a separator 12, i.e., the surface of the negative electrode current collector 111 to which the SiOC ceramic fiber film 112 is adhered is disposed opposite to the surface of the positive electrode current collector 131 to which the active material layer 132 is adhered.
Further, the SiOC ceramic fiber film is 90 to 99% and the silver conductive agent is 1 to 10% by mass relative to the total mass of the SiOC ceramic fiber film and the silver conductive agent.
Further, the SiOC ceramic fiber film 112 has a thickness of 50 μm to 150 μm; forming SiOC ceramic fiber film 112 by aligning a plurality of SiOC ceramic fiber filaments, each SiOC ceramic fiber filament having a diameter of 100nm to 50 μm;
further, the negative electrode current collector 111 is a copper foil having a thickness of 3-12 μm;
further, the separator 12 is made of polypropylene (PP) or Polyethylene (PE);
further, the positive electrode current collector 113 is an aluminum foil with a thickness of 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 adhesive;
further, the mass of the active material layer 132 is 100-250mg/cm 2 The compacted density is 3-4g/cm 3 ；
Further, the positive electrode active material is selected from one of lithium cobaltate, lithium manganate, lithium iron phosphate and high nickel ternary materials; the conductive agent is conductive carbon black (super-p); the binder is polyvinylidene fluoride (PVDF);
further, the outer package 2 is a thermoplastic tube, and the heat shrinkage ratio is 1% -500%.
Further, the electrolyte is 1mol/L LiPF 6 The solution and the solvent are DEC and EC with the volume ratio of 1:1.
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 yarn: taking spinning solution as a raw material, preparing SiC fiber yarn through electrostatic spinning treatment with spinning voltage of 5-30Kv and spinning speed of 0.1-5mL/h, and sintering the SiC fiber yarn at 150-400 ℃ for 5-24h in air atmosphere to prepare SiOC ceramic fiber yarn; wherein, 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.
(2) Preparation of negative electrode 11: forming an SiOC ceramic fiber film 112 by aligning a plurality of SiOC ceramic fiber filaments, 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 obtain a negative electrode 11;
(3) Preparation of positive electrode 13: dissolving an anode active material, a conductive agent and a binder in NMP according to a certain mass ratio to prepare slurry, uniformly coating the slurry on an anode current collector 131, and carrying out vacuum drying and rolling treatment to prepare an anode 13;
(4) Preparation of electrode assembly 1: electrode assembly 1 was obtained by sequentially stacking negative electrode 11 (surface to which SiOC ceramic fiber film 112 was adhered upward), separator 12, and positive electrode 13 (surface to which active material layer 132 was adhered downward);
(5) And (3) packaging: and sleeving the electrode assembly 1 into the outer packaging body 2, then injecting electrolyte into the outer packaging body 2, and then adopting phenolic resin to end-cap two ends of the outer packaging body 2 to obtain the flexible lithium ion battery.
The present invention will be described in further detail with reference to specific examples.
Example 1 a method of preparing a flexible lithium ion battery comprising:
(1) Preparation of SiOC ceramic fiber yarn: a spinning solution is obtained by dissolving polycarbosilane (molecular weight is 1500) and polyvinylpyrrolidone (PVP) in tetrahydrofuran, wherein the spinning solution comprises the following components in percentage by mass: 80% of polycarbosilane, 3.5% of polyvinylpyrrolidone and the balance of 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 filaments with the diameters of 15-30 mu m are obtained, and then sintering the SiC fiber filaments for 5h at 240 ℃ under the air atmosphere to obtain SiOC ceramic fiber filaments;
(2) Preparation of the negative electrode: a plurality of SiOC ceramic fiber filaments are directionally arranged to form a 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 85:15 in percentage by mass;
(3) Preparation of positive electrode: the lithium cobaltate, carbon black and PVDF are mixed according to the mass ratio of 97:1.5:1.5 is dissolved in NMP to prepare slurry, then the slurry is uniformly coated on aluminum foil with the thickness of 9 mu m, and the active substance layer with the mass of 180mg/cm is obtained after vacuum drying and rolling treatment 2 A compacted density of 3.5g/cm 3 A positive electrode;
(4) Preparation of electrode assembly: sequentially stacking a negative electrode (with the surface to which the SiOC ceramic fiber film is adhered facing upward), a separator PE, and a positive electrode (with the surface to which the active material layer is adhered facing downward) to obtain an electrode assembly;
(5) And (3) packaging: the electrode assembly was put into a thermoplastic tube having a diameter of 10mm, a length of 22cm and a heat shrinkage ratio of 50%, and 1mol/L of lithium hexafluorophosphate (LiPF) was injected into the thermoplastic tube 6 ) The solvent is Ethylene Carbonate (EC): ethyl carbonate (DMC) =1: and (3) the electrolyte with the volume ratio of 1 is used for sealing the two ends of the thermoplastic pipe by adopting phenolic resin to obtain the flexible lithium ion battery with the capacity of 800 mAh.
Comparative example 1
In comparative example 1, siOC ceramic fiber yarn was prepared in step (1) by sintering SiC fiber yarn at 500℃for 5 hours under an air atmosphere, and the remainder was the same as in example 1.
Performance test:
the flexible lithium ion batteries prepared in example 1 and comparative example 1 were subjected to a first discharge specific volume and cycle performance test at 0.5C under room temperature conditions (25 ℃ ±1) at a voltage of 3.0 to 4.3V under unbent and manual bending 50 times, respectively, and the test results are shown in table 1.
TABLE 1
The foregoing description of the preferred embodiments of the invention is not intended to limit the invention to the particular embodiments disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.
Claims (11)
1. The flexible lithium ion battery cathode is characterized by comprising a cathode 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 cathode current collector through the silver conductive agent, and the SiOC ceramic fiber film is formed by directional arrangement of a plurality of SiOC ceramic fiber filaments;
the negative electrode current collector is copper foil and has a thickness of 3-12 mu m;
the thickness of the SiOC ceramic fiber film is 50-150 mu m;
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.
2. The flexible lithium ion battery negative electrode of claim 1, wherein the SiOC ceramic fiber filaments have a diameter of 100nm-50 μιη.
3. A method for preparing the negative electrode of the flexible lithium ion battery as claimed in claim 1 or 2, comprising: siOC ceramic fiber filaments are obtained by sintering SiC fiber filaments serving as raw materials, then a plurality of SiOC ceramic fiber filaments are directionally arranged to form an SiOC ceramic fiber film, and then the SiOC ceramic fiber film is attached to one surface of a negative electrode current collector through a silver conductive agent.
4. The method for preparing a flexible lithium ion battery cathode according to claim 3, wherein the sintering treatment is performed in an air atmosphere, the sintering temperature is 150 ℃ to 400 ℃, and the sintering time is 5 to 24 hours.
5. The method for preparing the flexible lithium ion battery cathode according to claim 3, 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 method for preparing the negative electrode of the flexible lithium ion battery according to claim 5, wherein the SiC fiber precursor is selected from one or more of polycarbosilane, polysiloxane, polymethylsilane and polysilane; 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 oleic acid ester; 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. The method for preparing a negative electrode of a flexible lithium ion battery according to claim 6, wherein the SiC fiber precursor is polycarbosilane and has a molecular weight of 1000-2000.
8. A flexible lithium ion battery comprising: the flexible lithium ion battery is prepared by packaging the electrode assembly, the electrolyte and the outer packaging body through the outer packaging body; 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 of claim 1 or 2 or the flexible lithium ion battery negative electrode prepared by the preparation method of any one of claims 3-6.
9. The flexible lithium ion battery of claim 8, wherein the outer encapsulant is a thermoplastic tube having a heat shrinkage ratio of 1% -500%.
10. The flexible lithium ion battery of claim 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 adhesive; 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 The method comprises the steps of carrying out a first treatment on the surface of the And/or the positive electrode active material is selected from one of lithium cobaltate, lithium manganate, lithium iron phosphate and high nickel ternary materials; the conductive agent is conductive carbon black; the binder is polyvinylidene fluoride; the positive electrode current collector is aluminum foil and has a thickness of 3-12 mu m.
11. The flexible lithium ion battery of claim 8, wherein the separator is made of polypropylene or polyethylene; liPF with electrolyte of 1mol/L 6 The solution comprises diethyl carbonate and ethylene carbonate in a volume ratio of 1:1; and/or the packaging treatment is that the electrode assembly is sleeved into the outer packaging body, then electrolyte is injected into the outer packaging body, and then the two ends of the outer packaging body are blocked 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 |
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| "Self-supporting carbon-rich SiOC ceramic electrodes for lithium-ion batteries and aqueoussupercapacitors";Shakir Bin Mujib等;《RSC Advances》;第第11卷卷(第第56期期);第35440-35454页 * |
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