CN112289592A - Lithium ion capacitor and preparation method thereof - Google Patents
Lithium ion capacitor and preparation method thereof Download PDFInfo
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- 239000003990 capacitor Substances 0.000 title claims abstract description 106
- 238000002360 preparation method Methods 0.000 title claims abstract description 20
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims abstract description 183
- 229910052744 lithium Inorganic materials 0.000 claims abstract description 183
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- 239000000203 mixture Substances 0.000 claims abstract description 22
- 239000007774 positive electrode material Substances 0.000 claims description 48
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- 230000002687 intercalation Effects 0.000 claims description 29
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- HFCVPDYCRZVZDF-UHFFFAOYSA-N [Li+].[Co+2].[Ni+2].[O-][Mn]([O-])(=O)=O Chemical compound [Li+].[Co+2].[Ni+2].[O-][Mn]([O-])(=O)=O HFCVPDYCRZVZDF-UHFFFAOYSA-N 0.000 description 3
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
- H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
- H01G11/22—Electrodes
- H01G11/30—Electrodes characterised by their material
- H01G11/32—Carbon-based
- H01G11/34—Carbon-based characterised by carbonisation or activation of carbon
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
- H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
- H01G11/04—Hybrid capacitors
- H01G11/06—Hybrid capacitors with one of the electrodes allowing ions to be reversibly doped thereinto, e.g. lithium ion capacitors [LIC]
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
- H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
- H01G11/22—Electrodes
- H01G11/30—Electrodes characterised by their material
- H01G11/50—Electrodes characterised by their material specially adapted for lithium-ion capacitors, e.g. for lithium-doping or for intercalation
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
- H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
- H01G11/84—Processes for the manufacture of hybrid or EDL capacitors, or components thereof
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- 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
- Y02E60/13—Energy storage using capacitors
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Abstract
The invention belongs to the technical field of lithium ion capacitors, and particularly relates to a lithium ion capacitor and a preparation method thereof. According to the invention, the mixture of the activated carbon and the lithium ion battery anode material is used as the anode active material, so that the anode can simultaneously exert an electric double layer mechanism and an oxidation-reduction reaction mechanism, and has higher rate performance and energy density. Meanwhile, the negative active layer adopts the negative active layer pre-embedded with lithium, so the negative electrode has a certain lithium embedding amount, thereby achieving the effect of positive and negative double-embedding of lithium, and the obtained lithium ion capacitor has higher energy density and power density, excellent electrochemical performance and good application prospect.
Description
Technical Field
The invention belongs to the technical field of lithium ion capacitors, and particularly relates to a lithium ion capacitor and a preparation method thereof.
Background
With the rapid development of the fields of wind power generation, photovoltaic power generation, mobile electronic equipment and the like in recent years, the requirements on the energy density and the power density of an energy storage device are higher and higher. The lithium ion battery has high energy density, low power density and short cycle life as a secondary battery with the widest application and the most development potential. The electric double layer super capacitor has high power performance and million cycle life, but its energy density is much lower than that of the lithium ion secondary battery. Therefore, in order to obtain an energy storage device with high energy and high power density, researchers have developed a brand-new energy storage device, namely a Lithium Ion Capacitor (LIC), wherein the positive electrode material of the lithium ion capacitor is mostly the activated carbon material of an electric double layer super capacitor, and the negative electrode is the negative electrode material of a lithium ion battery pre-embedded with lithium.
Since the lithium ion capacitor needs to pre-embed lithium into the negative electrode, the manufacturing technology process is more complicated than that of the double electric layer super capacitor and the lithium ion battery, and finding an optimal pre-embedding lithium technology is a currently recognized technical difficulty. The existing lithium pre-intercalation mode generally has the problems of complex process, higher production cost, long lithium intercalation time, difficult control of lithium intercalation uniformity and poor safety.
Disclosure of Invention
The invention aims to provide a lithium ion capacitor and a preparation method thereof, and aims to solve the technical problems of poor pre-lithium intercalation effect and low power performance in the conventional lithium ion capacitor.
In order to achieve the above object, in one aspect of the present invention, there is provided a lithium ion capacitor including a positive electrode, a negative electrode and a separator disposed therebetween, the positive electrode including a positive electrode current collector and a positive electrode active layer bonded to a surface of the positive electrode current collector, the positive electrode active layer including a positive electrode active material; the negative electrode comprises a negative electrode current collector and a negative electrode active layer combined on the surface of the negative electrode current collector, wherein the negative electrode active layer comprises a carbon material, and the positive electrode active material comprises a mixture of activated carbon and a positive electrode material of a lithium ion battery; the negative electrode active layer is a lithium pre-intercalated negative electrode active layer.
According to the lithium ion capacitor provided by the invention, the mixture of the activated carbon and the lithium ion battery anode material is used as the anode active material, so that the anode can simultaneously play a double electric layer mechanism and a redox reaction mechanism, and has higher rate performance and energy density. Meanwhile, the negative active layer adopts the negative active layer pre-embedded with lithium, so the negative electrode also has a certain lithium embedding amount, thereby achieving the effect of double lithium embedding of the positive electrode and the negative electrode. The lithium ion capacitor provided by the invention has higher energy density and power density, excellent electrochemical performance and good application prospect due to the double lithium intercalation at the anode and the cathode.
In a preferred embodiment of the lithium ion capacitor according to the present invention, in the positive electrode active material, a mass ratio of the activated carbon to the positive electrode material of the lithium ion battery is (1-30): 1.
As a preferable embodiment of the lithium ion capacitor of the present invention, the lithium ion battery positive electrode material is at least one selected from a lithium metal oxide, a lithium sulfur composite, and a lithium polymer.
In a further preferred embodiment of the method for producing a lithium ion capacitor according to the present invention, the lithium metal oxide is selected from LiMO2、LiNiaX1-aO2、LiNibMncCo1-b-cO2、LiYdMn2-dO4、LiFePO4、Li3V2(PO4)3At least one of;
wherein, LiMO2In the formula, M is Co, Ni, Mn, Cu or Fe;
LiNiaX1-aO2wherein X is Co, Mn, Cu, Al, Mg, Fe, La, V, Zn or Cr, and 0<a<1；
LiNibMncCo1-b-cO2Middle, 0<b<1，0<c<1；
LiYdMn2-dO4In which Y is Ni, Co or Al, and 0<d<1。
As a preferable technical solution of the lithium ion capacitor of the present invention, the mass of the positive electrode active material accounts for 70% to 95% of the mass of the positive electrode active layer, based on 100% of the total mass of the positive electrode active layer.
In a preferred embodiment of the lithium ion capacitor according to the present invention, the mass of the carbon material accounts for 80% to 95% of the mass of the negative electrode active layer, based on 100% of the total mass of the negative electrode active layer.
In a preferred embodiment of the lithium ion capacitor according to the present invention, the carbon material is at least one selected from graphite, hard carbon, soft carbon, and mesocarbon microbeads.
In another aspect of the present invention, a method for preparing a lithium ion capacitor is provided, which includes the following steps:
providing a positive electrode, wherein the positive electrode comprises a positive electrode current collector and a positive electrode active layer combined on the surface of the positive electrode current collector, the positive electrode active layer comprises a positive electrode active material, and the positive electrode active material comprises a mixture of active carbon and a positive electrode material of a lithium ion battery;
providing a negative electrode, wherein the negative electrode comprises a negative electrode current collector and a negative electrode active layer combined on the surface of the negative electrode current collector, the negative electrode active layer comprises a carbon material, and the negative electrode active layer is subjected to pre-lithium intercalation treatment;
stacking or winding the anode, the diaphragm and the cathode, adding electrolyte, and packaging to obtain the lithium ion capacitor;
the method for pre-embedding lithium into the negative active layer comprises the following steps: and providing a lithium tape, arranging the lithium tape on the surface of one side of the negative active layer, which is far away from the negative current collector, and standing for 24-48 h.
In the preparation method of the lithium ion capacitor, firstly, the mixture of the activated carbon and the lithium ion battery anode material is used as the anode active material, so that the obtained anode can simultaneously exert an electric double layer mechanism and an oxidation-reduction reaction mechanism, and has higher rate performance and energy density; and secondly, arranging the lithium strip on the surface of the negative electrode active layer, embedding the lithium strip into the negative electrode active layer along with the standing and the charging and discharging reaction to obtain a pre-lithium-embedded negative electrode active layer, so that the obtained negative electrode also achieves a certain lithium embedding amount, and the effect of double lithium embedding of the positive electrode and the negative electrode is achieved. By adopting the method to embed lithium into the anode and the cathode, the obtained lithium ion capacitor has the electrochemical properties of high energy density and high power density. In addition, the pre-lithium intercalation mode provided by the invention is simple and convenient to operate, is beneficial to saving the lithium intercalation time, can realize effective control on the lithium intercalation amount, and increases the controllability of pre-lithium intercalation.
As a preferable technical solution of the method for manufacturing a lithium ion capacitor according to the present invention, the number of the lithium strips is two or more, and when the lithium strips are disposed on the surface of the negative electrode active layer, a gap is left between two adjacent lithium strips.
In a preferred embodiment of the method for producing a lithium ion capacitor according to the present invention, the mass ratio of the total mass of the lithium ribbon to the carbon material is (0.01-1): 1.
As a further preferable technical scheme of the preparation method of the lithium ion capacitor, the thickness of each lithium strip is 25-75 μm, the length is 1-8 mm, and the width is 0.5-2 mm.
Drawings
FIG. 1 is a graph showing rate characteristics of lithium ion capacitors obtained in examples 1 to 5 of the present invention and comparative examples 1 to 4.
Detailed Description
In order to make the objects, technical solutions and technical effects of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described, and the embodiments described below are a part of the embodiments of the present invention, but not all of the embodiments. All other embodiments obtained by a person of ordinary skill in the art without any inventive step in connection with the embodiments of the present invention shall fall within the scope of protection of the present invention. Those whose specific conditions are not specified in the examples are carried out according to conventional conditions or conditions recommended by the manufacturer; the reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.
In the description of the present invention, the term "and/or" describing an association relationship of associated objects means that there may be three relationships, for example, a and/or B, may mean: a is present alone, A and B are present simultaneously, and B is present alone. Wherein A and B can be singular or plural. The character "/" generally indicates that the former and latter associated objects are in an "or" relationship.
In the description of the present invention, "at least one" means one or more, "a plurality" means two or more. "at least one of the following" or similar expressions refer to any combination of these items, including any combination of the singular or plural items. For example, "at least one (a), b, or c", or "at least one (a), b, and c", may each represent: a. b, c, a-b (i.e. a and b), a-c, b-c, or a-b-c, wherein a, b, and c can be single or multiple respectively.
It should be understood that the weight of the related components mentioned in the embodiments of the present invention may not only refer to the specific content of each component, but also represent the proportional relationship of the weight among the components, and therefore, it is within the scope of the disclosure that the content of the related components is scaled up or down according to the embodiments of the present invention. Specifically, the weight described in the embodiments of the present invention may be a unit of mass known in the chemical field such as μ g, mg, g, kg, etc.
In addition, unless the context clearly uses otherwise, an expression of a word in the singular is to be understood as including the plural of the word. The terms "comprises" or "comprising" are intended to specify the presence of stated features, quantities, steps, operations, elements, portions, or combinations thereof, but are not intended to preclude the presence or addition of one or more other features, quantities, steps, operations, elements, portions, or combinations thereof.
The embodiment of the invention provides a lithium ion capacitor, which comprises a positive electrode, a negative electrode and a diaphragm, wherein the positive electrode and the negative electrode are oppositely arranged, the diaphragm is arranged between the positive electrode and the negative electrode, the positive electrode comprises a positive electrode current collector and a positive electrode active layer combined on the surface of the positive electrode current collector, and the positive electrode active layer comprises a positive electrode active material; the negative electrode comprises a negative electrode current collector and a negative electrode active layer combined on the surface of the negative electrode current collector, the negative electrode active layer comprises a carbon material, and the positive electrode active material comprises a mixture of active carbon and a positive electrode material of the lithium ion battery; the negative electrode active layer is a lithium pre-intercalated negative electrode active layer.
According to the lithium ion capacitor provided by the embodiment of the invention, the mixture of the activated carbon and the lithium ion battery anode material is used as the anode active material, so that the anode can simultaneously exert an electric double layer mechanism and an oxidation-reduction reaction mechanism, and has higher rate performance and energy density. Meanwhile, the negative active layer adopts the negative active layer pre-embedded with lithium, so the negative electrode also has a certain lithium embedding amount, thereby achieving the effect of double lithium embedding of the positive electrode and the negative electrode. The lithium ion capacitor provided by the embodiment of the invention has higher energy density and power density, excellent electrochemical performance and good application prospect because the lithium is embedded in the anode and the cathode in a double-embedding manner.
In some embodiments, the mass ratio of activated carbon to lithium ion battery positive electrode material is controlled to be (1-30): 1. By doping a proper amount of lithium ion battery anode material in the activated carbon, the obtained anode active material contains the activated carbon and lithium at the same time, can simultaneously exert double electric layers and redox reaction mechanisms, and has higher energy density and high power characteristics. If the doping amount of the lithium ion battery anode material is too much, the specific surface area of the anode plate is influenced to a certain extent, so that the exertion of a double electric layer mechanism is inhibited, and the power performance of the lithium ion battery anode material is reduced. If the doping amount is too small, the capacity of the lithium ion capacitor cannot be significantly increased. Specifically, typical, but non-limiting, mass ratios between the activated carbon and the lithium ion battery positive electrode material are 1:1, 5:1, 10:1, 15:1, 20:1, 25:1, 30: 1.
In some embodiments, the lithium ion battery positive electrode material is selected from at least one of lithium composite metal oxides, lithium sulfur composites, lithium polymers. In some embodiments, the lithium composite metal oxide is selected from LiMO2、LiNiaX1-aO2、LiNibMncCo1-b-cO2、LiYdMn2-dO4、LiFePO4、Li3V2(PO4)3At least one of; wherein, LiMO2In the formula, M is Co, Ni, Mn, Cu or Fe; LiNiaX1-aO2Wherein X is Co, Mn, Cu, Al, Mg, Fe, La, V, Zn or Cr, and 0<a<1；LiNibMncCo1-b-cO2Middle, 0<b<1，0<c<1；LiYdMn2-dO4In which Y is Ni, Co or Al, and 0<d<1。
In some embodiments, the mass of the positive electrode active material accounts for 70% to 95% of the mass of the positive electrode active layer, based on 100% of the total mass of the positive electrode active layer. By optimizing the content of the positive electrode active material in the positive electrode active layer, the obtained positive electrode has higher energy density, and the electrochemical performance of the obtained lithium ion capacitor is favorably improved.
As a specific embodiment, the positive active layer comprises activated carbon, a lithium ion battery positive material, a conductive agent and a binder, and the mass ratio of the activated carbon to the lithium ion battery positive material is (65-85) to (5-30) to (1-10). By optimizing the mass ratio of the four components, the obtained positive electrode has higher energy density and good conductivity and stability. The embodiment of the present invention is not particularly limited to the specific selection of the conductive agent and the binder, and the conductive agent and the binder commonly used in the art may be used.
In some embodiments, the mass of the carbon material accounts for 80% to 95% of the mass of the negative electrode active layer, based on 100% of the total mass of the negative electrode active layer. By optimizing the content of the carbon material in the negative electrode active layer, the doping amount of the obtained negative electrode can be increased, and the charge and discharge performance of the obtained lithium ion capacitor can be improved.
In some embodiments, the carbon material in the negative active layer is selected from at least one of graphite, hard carbon, soft carbon, mesocarbon microbeads, and silicon carbon material. These carbon materials are used as a common negative electrode material for lithium ion batteries, have a structure such as a suitable interlayer spacing, and can receive lithium ions from a positive electrode to perform intercalation/deintercalation.
As a specific embodiment, the negative electrode active layer includes a carbon material, a conductive agent, a binder, and a dispersant in a mass ratio of (80-95): (1-10): (1-5). By optimizing the mass ratio of the four components, the conductivity and the stability of the cathode are improved. The embodiment of the present invention is not particularly limited to the specific selection of the conductive agent, the binder, and the dispersant, and any conductive agent, binder, and dispersant commonly used in the art may be used.
The lithium ion capacitor provided by the embodiment of the invention can be prepared by the following preparation method.
Correspondingly, the embodiment of the invention also provides a preparation method of the lithium ion capacitor, which comprises the following steps:
s1, providing a positive electrode, wherein the positive electrode comprises a positive electrode current collector and a positive electrode active layer combined on the surface of the positive electrode current collector, the positive electrode active layer comprises a positive electrode active material, and the positive electrode active material comprises a mixture of active carbon and a positive electrode material of a lithium ion battery;
s2, providing a negative electrode, wherein the negative electrode comprises a negative electrode current collector and a negative electrode active layer combined on the surface of the negative electrode current collector, the negative electrode active layer comprises a carbon material, and the negative electrode active layer is subjected to pre-lithium intercalation treatment;
s3, stacking or winding the anode, the diaphragm and the cathode, adding electrolyte, and packaging to obtain the lithium ion capacitor;
the method for pre-embedding lithium into the negative active layer comprises the following steps: and providing a lithium belt, arranging the lithium belt on the surface of the side, away from the negative current collector, of the negative active layer, and standing for 24-48 h.
It should be noted that, although the steps S1 and S2 describe the preparation process of the lithium ion capacitor in a specific order, it is not required that the steps are necessarily performed in the specific order, and the steps may be performed simultaneously or in any order.
In the preparation method of the lithium ion capacitor provided by the embodiment of the invention, firstly, the mixture of the activated carbon and the lithium ion battery anode material is used as the anode active material, so that the obtained anode can simultaneously exert an electric double layer mechanism and a redox reaction mechanism, thereby having higher rate performance and energy density; and secondly, arranging the lithium strip on the surface of the negative electrode active layer, embedding the lithium strip into the negative electrode active layer along with the standing and the charging and discharging reaction to obtain a pre-lithium-embedded negative electrode active layer, so that the obtained negative electrode also achieves a certain lithium embedding amount, and the effect of double lithium embedding of the positive electrode and the negative electrode is achieved. By adopting the method to embed lithium into the anode and the cathode, the obtained lithium ion capacitor has the electrochemical properties of high energy density and high power density. In addition, the pre-lithium intercalation mode provided by the embodiment of the invention is simple and convenient to operate, is beneficial to saving the lithium intercalation time, can realize effective control on the lithium intercalation amount, and increases the controllability of pre-lithium intercalation.
Specifically, in S1, the preparation method of the positive electrode may adopt a conventional method in the art, and any method that uses a mixture of activated carbon and a positive electrode material of a lithium ion battery as a positive electrode active material to prepare a positive electrode active layer and then combines the positive electrode active layer with the surface of a positive electrode current collector is suitable for the embodiment of the present invention. The mass ratio of the activated carbon to the lithium ion battery positive electrode material, the specific selection of the lithium ion battery positive electrode material, and the mass ratio of the positive electrode active material in the positive electrode active layer are as described above, and are not repeated here for saving space.
As a specific embodiment, the step of preparing the positive electrode includes: preparing the active carbon, the lithium ion battery anode material, the conductive agent and the binder according to the mass ratio of (65-85) to (5-30) to (1-10), adding the materials into a solvent, and mixing to prepare the anode slurry. And coating the positive electrode slurry on the surface of a positive electrode current collector, and performing drying treatment and tabletting treatment to obtain the positive electrode.
In S2, the method for preparing the negative electrode includes two steps, the first step is to prepare a negative electrode current collector and a negative electrode active layer bonded to the surface of the negative electrode current collector, and the second step is to pre-embed lithium in the negative electrode active layer. In the first section, the negative electrode current collector and the method of bonding the negative electrode active layer to the surface of the negative electrode current collector may employ conventional methods in the art. The specific selection of the carbon material in the negative active layer and the mass ratio of the carbon material in the negative active layer are as described above, and are not described herein again for brevity.
As a specific embodiment, the preparation step of the first part comprises: preparing a carbon material, a conductive agent, a binder and a dispersing agent according to the mass ratio of (80-95) to (1-10) to (1-5), adding the prepared materials into a solvent, and mixing to prepare a negative electrode slurry. And coating the negative electrode slurry on the surface of a negative electrode current collector, and performing drying treatment and tabletting treatment to obtain the negative electrode.
In the second aspect, a method of subjecting the negative electrode active layer to a lithium pre-intercalation treatment includes: and providing a lithium belt, and arranging the lithium belt on the surface of the negative electrode active layer on the side away from the negative electrode current collector. The negative electrode active material is a carbon material and has the characteristic of lithium intercalation, and during standing or charging and discharging, a lithium band is used as a simple substance lithium source to be intercalated into the carbon material of the negative electrode active layer, so that the lithium band disappears, the negative electrode active layer with pre-intercalated lithium is obtained, and the pre-intercalated lithium is completed. In some embodiments, the number of the lithium strips is more than two, and when the lithium strips are arranged on the surface of the negative active layer, a gap should be left between two adjacent lithium strips to form a channel, so that the transmission of lithium ions is facilitated. Meanwhile, by arranging more than two lithium belts, the lithium pre-insertion can be more efficiently completed, the lithium insertion amount can be controlled, and the controllability of the lithium pre-insertion process is improved.
In some embodiments, the ratio of the total mass of the lithium strips to the mass of the carbon material is controlled (0.01-1): 1. By controlling the mass ratio of the lithium belt to the carbon material, the control of the lithium intercalation amount can be realized, the pre-intercalation depth of the cathode is further controlled, and the safety, reliability, accuracy and controllability of the process are realized. Specifically, typical but non-limiting mass ratios between the total mass of the lithium ribbon and the carbon material are 0.01:1, 0.05:1, 0.1:1, 0.5:1, 1: 1.
In some embodiments, the thickness of each lithium ribbon is controlled to be 25 μm to 75 μm, the length is controlled to be 1mm to 8mm, and the width is controlled to be 0.5mm to 2 mm. The lithium belt with micron grade is cut into the specific shape with the size and the thickness, so that the lithium belt can be placed at different positions of the negative electrode active layer more conveniently, the lithium embedding speed can be greatly improved, and the lithium embedding time is effectively saved. Meanwhile, the thickness and the size of the lithium belt are moderate, and the uniformity of lithium insertion can be improved. In particular, each lithium strip typically, but not by way of limitation, has a thickness of 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm; each lithium strip is typically, but not limited to, 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm in length; typical but not limiting widths of each lithium strip are 0.5mm, 1mm, 1.5mm, 2 mm.
In order to make the above implementation details and operations of the present invention clearly understood by those skilled in the art and to make the progress of the lithium ion capacitor and the manufacturing method thereof obvious, the above technical solution is illustrated by the following examples.
Example 1
The embodiment provides a preparation method of a lithium ion capacitor, which comprises the following steps:
(11) preparing a positive plate: weighing Activated Carbon (AC), Lithium Cobaltate (LCO), conductive carbon black and polyvinylidene fluoride (PVDF) according to the mass ratio of 85:5:4:6, grinding the weighed materials by taking N-methyl pyrrolidone (NMP) as a solvent to form slurry-like slurry, coating the slurry-like slurry on a positive current collector, drying the slurry by a vacuum drying box, rolling and punching to obtain a positive plate;
(12) preparing a negative plate: weighing mesocarbon microbeads (MCMB), conductive carbon black, styrene butadiene rubber emulsion (SBR) and carboxymethyl cellulose (CMC) according to a mass ratio of 91:4:3:2, adding a proper amount of deionized water, grinding to form slurry, coating the slurry on a negative current collector, drying by a vacuum drying oven, rolling, and punching to obtain a negative plate; and (3) parallelly placing 3 lithium strips on the negative plate, reserving gaps between adjacent lithium strips, assembling each lithium strip into a lithium ion capacitor with the thickness of 55 microns, the length of 3mm and the width of 1mm, and standing for 33h to enable lithium in the lithium strips to be completely embedded into the negative plate. The ratio of the total mass of the lithium ribbon to the mass of the negative electrode active material MCMB was 0.08: 1;
(13) assembling: assembling the button capacitor according to the sequence of the negative electrode shell, the negative electrode sheet, the diaphragm, the positive electrode sheet, the gasket, the spring sheet and the positive electrode shell, and adding a proper amount of electrolyte (1mol/L LiPF)6(EC: PC: DEC: 1:1:1V/V/V)) was dropped on the positive electrode sheet and the negative electrode sheet, and the resultant was sealed with a sealer at 150kg/cm2And sealing the pressure to obtain the lithium ion capacitor.
Example 2
The embodiment provides a preparation method of a lithium ion capacitor, which comprises the following steps:
(21) preparing a positive plate: weighing Activated Carbon (AC), Lithium Cobaltate (LCO), conductive carbon black and polyvinylidene fluoride (PVDF) according to the mass ratio of 80:10:4:6, grinding the weighed materials by taking N-methyl pyrrolidone (NMP) as a solvent to form slurry-like slurry, coating the slurry-like slurry on a positive current collector, drying the slurry by a vacuum drying box, rolling and punching to obtain a positive plate;
(22) preparing a negative plate: weighing mesocarbon microbeads (MCMB), conductive carbon black, styrene butadiene rubber emulsion (SBR) and carboxymethyl cellulose (CMC) according to a mass ratio of 91:4:3:2, adding a proper amount of deionized water, grinding to form slurry, coating the slurry on a negative current collector, drying by a vacuum drying oven, rolling, and punching to obtain a negative plate; and (3) parallelly placing 3 lithium strips on the negative plate, reserving gaps between adjacent lithium strips, assembling each lithium strip into a lithium ion capacitor with the thickness of 55 microns, the length of 3mm and the width of 1mm, and standing for 33h to enable lithium in the lithium strips to be completely embedded into the negative plate. The ratio of the total mass of the lithium ribbon to the mass of the negative electrode active material MCMB was 0.08: 1;
(23) assembling: assembling the button capacitor according to the sequence of the negative electrode shell, the negative electrode sheet, the diaphragm, the positive electrode sheet, the gasket, the spring sheet and the positive electrode shell, and adding a proper amount of electrolyte (1mol/L LiPF)6(EC: PC: DEC: 1:1:1V/V/V)) was dropped on the positive electrode sheet and the negative electrode sheet, and the resultant was sealed with a sealer at 150kg/cm2And sealing the pressure to obtain the lithium ion capacitor.
Example 3
The embodiment provides a preparation method of a lithium ion capacitor, which comprises the following steps:
(31) preparing a positive plate: weighing Activated Carbon (AC), Lithium Cobaltate (LCO), conductive carbon black and polyvinylidene fluoride (PVDF) according to the mass ratio of 75:15:4:6, grinding the mixture by taking N-methyl pyrrolidone (NMP) as a solvent to form slurry, coating the slurry on a positive current collector, drying the slurry by a vacuum drying box, rolling and punching to obtain the positive plate.
(32) Preparing a negative plate: weighing mesocarbon microbeads (MCMB), conductive carbon black, styrene butadiene rubber emulsion (SBR) and carboxymethyl cellulose (CMC) according to a mass ratio of 91:4:3:2, adding a proper amount of deionized water, grinding to form slurry, coating the slurry on a negative current collector, drying by a vacuum drying oven, rolling, and punching to obtain a negative plate; and (3) parallelly placing 3 lithium strips on the negative plate, reserving gaps between adjacent lithium strips, assembling each lithium strip into a lithium ion capacitor with the thickness of 55 microns, the length of 3mm and the width of 1mm, and standing for 33h to enable lithium in the lithium strips to be completely embedded into the negative plate. The ratio of the total mass of the lithium ribbon to the mass of the negative electrode active material MCMB was 0.08: 1;
(33) assembling: assembling the button capacitor according to the sequence of the negative electrode shell, the negative electrode sheet, the diaphragm, the positive electrode sheet, the gasket, the spring sheet and the positive electrode shell, and adding a proper amount of electrolyte (1mol/L LiPF)6(EC: PC: DEC: 1:1:1V/V/V)) was dropped on the positive electrode sheet and the negative electrode sheet, and the resultant was sealed with a sealer at 150kg/cm2And sealing the pressure to obtain the lithium ion capacitor.
Example 4
The embodiment provides a preparation method of a lithium ion capacitor, which comprises the following steps:
(41) preparing a positive plate: weighing Activated Carbon (AC), Lithium Cobaltate (LCO), conductive carbon black and polyvinylidene fluoride (PVDF) according to the mass ratio of 70:20:4:6, grinding the mixture by taking N-methyl pyrrolidone (NMP) as a solvent to form slurry, coating the slurry on a positive current collector, drying the slurry by a vacuum drying box, rolling and punching to obtain the positive plate.
(42) Preparing a negative plate: weighing mesocarbon microbeads (MCMB), conductive carbon black, styrene butadiene rubber emulsion (SBR) and carboxymethyl cellulose (CMC) according to a mass ratio of 91:4:3:2, adding a proper amount of deionized water, grinding to form slurry, coating the slurry on a negative current collector, drying by a vacuum drying oven, rolling, and punching to obtain a negative plate; and (3) parallelly placing 3 lithium strips on the negative plate, reserving gaps between adjacent lithium strips, assembling each lithium strip into a lithium ion capacitor with the thickness of 55 microns, the length of 3mm and the width of 1mm, and standing for 33h to enable lithium in the lithium strips to be completely embedded into the negative plate. The ratio of the total mass of the lithium ribbon to the mass of the negative electrode active material MCMB was 0.08: 1;
(43) assembling: assembling the button capacitor according to the sequence of the negative electrode shell, the negative electrode sheet, the diaphragm, the positive electrode sheet, the gasket, the spring sheet and the positive electrode shell, and adding a proper amount of electrolyte (1mol/L LiPF)6(EC: PC: DEC: 1:1:1V/V/V)) was dropped on the positive electrode sheet and the negative electrode sheet, and the resultant was sealed with a sealer at 150kg/cm2Pressure sealing of to obtain lithiumAn ion capacitor.
Example 5
The embodiment provides a preparation method of a lithium ion capacitor, which comprises the following steps:
(51) preparing a positive plate: weighing Activated Carbon (AC), nickel cobalt lithium manganate (ternary NCM532), conductive carbon black and polyvinylidene fluoride (PVDF) according to the mass ratio of 70:20:4:6, grinding the mixture by taking N-methyl pyrrolidone (NMP) as a solvent to form slurry-like slurry, coating the slurry-like slurry on a positive current collector, drying the slurry by a vacuum drying box, rolling and punching to obtain the positive plate.
(52) Preparing a negative plate: weighing mesocarbon microbeads (MCMB), conductive carbon black, styrene butadiene rubber emulsion (SBR) and carboxymethyl cellulose (CMC) according to a mass ratio of 91:4:3:2, adding a proper amount of deionized water, grinding to form slurry, coating the slurry on a negative current collector, drying by a vacuum drying oven, rolling, and punching to obtain a negative plate; and (3) parallelly placing 3 lithium strips on the negative plate, reserving gaps between adjacent lithium strips, assembling each lithium strip into a lithium ion capacitor with the thickness of 55 microns, the length of 3mm and the width of 1mm, and standing for 33h to enable lithium in the lithium strips to be completely embedded into the negative plate. The ratio of the total mass of the lithium ribbon to the mass of the negative electrode active material MCMB was 0.08: 1;
(53) assembling: assembling the button capacitor according to the sequence of the negative electrode shell, the negative electrode sheet, the diaphragm, the positive electrode sheet, the gasket, the spring sheet and the positive electrode shell, and adding a proper amount of electrolyte (1mol/L LiPF)6(EC: PC: DEC: 1:1:1V/V/V)) was dropped on the positive electrode sheet and the negative electrode sheet, and the resultant was sealed with a sealer at 150kg/cm2And sealing the pressure to obtain the lithium ion capacitor.
Comparative example 1
(61) Preparing a positive plate: weighing activated carbon, conductive carbon black and polyvinylidene fluoride (PVDF) according to a mass ratio of 90:4:6, grinding the mixture by taking N-methyl pyrrolidone (NMP) as a solvent to form slurry, coating the slurry on a positive current collector, drying the slurry in a vacuum drying oven, rolling the slurry, and punching the sheet to obtain a positive plate;
(62) weighing mesocarbon microbeads (MCMB), conductive carbon black, styrene butadiene rubber emulsion (SBR) and carboxymethyl cellulose (CMC) according to a mass ratio of 91:4:3:2, adding a proper amount of deionized water, grinding to form slurry, coating the slurry on a negative current collector, drying by a vacuum drying oven, rolling, and punching to obtain a negative plate;
(63) assembling: assembling the button capacitor according to the sequence of the negative electrode shell, the negative electrode sheet, the diaphragm, the positive electrode sheet, the gasket, the spring sheet and the positive electrode shell, and adding a proper amount of electrolyte (1mol/L LiPF)6(EC: PC: DEC: 1:1:1V/V/V)) was dropped on the positive electrode sheet and the negative electrode sheet, and the resultant was sealed with a sealer at 150kg/cm2And sealing the pressure to obtain the lithium ion capacitor.
Comparative example 2
(71) Preparing a positive plate: weighing the activated carbon, the conductive carbon black and the polyvinylidene fluoride (PVDF) according to the mass ratio of 90:4:6, grinding the mixture by taking N-methyl pyrrolidone (NMP) as a solvent to form slurry, coating the slurry on a positive current collector, drying the slurry by a vacuum drying oven, rolling and punching to obtain the positive plate.
(72) Preparing a negative plate: weighing mesocarbon microbeads (MCMB), conductive carbon black, styrene butadiene rubber emulsion (SBR) and carboxymethyl cellulose (CMC) according to a mass ratio of 91:4:3:2, adding a proper amount of deionized water, grinding to form slurry, coating the slurry on a negative current collector, drying by a vacuum drying oven, rolling, and punching to obtain a negative plate; and placing the lithium strips on different positions of the negative plate, leaving gaps between adjacent lithium strips, assembling each lithium strip into a lithium ion capacitor with the thickness of 55 microns, the length of 3mm and the width of 1mm, and standing for 33h to enable lithium in the lithium strips to be completely embedded into the negative plate. The ratio of the total mass of the lithium ribbon to the mass of the negative electrode active material MCMB was 0.08: 1;
(73) assembling: assembling the button capacitor according to the sequence of the negative electrode shell, the negative electrode sheet, the diaphragm, the positive electrode sheet, the gasket, the spring sheet and the positive electrode shell, and adding a proper amount of electrolyte (1mol/L LiPF)6(EC: PC: DEC: 1:1:1V/V/V)) was dropped on the positive electrode sheet and the negative electrode sheet, and the resultant was sealed with a sealer at 150kg/cm2And sealing the pressure to obtain the lithium ion capacitor.
Comparative example 3
The comparative example provides a method for preparing a lithium ion capacitor, comprising the following steps:
(81) preparing a positive plate: weighing Activated Carbon (AC), Lithium Cobaltate (LCO), conductive carbon black and polyvinylidene fluoride (PVDF) according to the mass ratio of 20:70:4:6, grinding the mixture by taking N-methyl pyrrolidone (NMP) as a solvent to form slurry, coating the slurry on a positive current collector, drying the slurry by a vacuum drying box, rolling and punching to obtain the positive plate.
(82) Preparing a negative plate: weighing mesocarbon microbeads (MCMB), conductive carbon black, styrene butadiene rubber emulsion (SBR) and carboxymethyl cellulose (CMC) according to a mass ratio of 91:4:3:2, adding a proper amount of deionized water, grinding to form slurry, coating the slurry on a negative current collector, drying by a vacuum drying oven, rolling, and punching to obtain a negative plate; and placing the lithium strips on different positions of the negative plate, leaving gaps between adjacent lithium strips, assembling each lithium strip into a lithium ion capacitor with the thickness of 55 microns, the length of 3mm and the width of 1mm, and standing for 33h to enable lithium in the lithium strips to be completely embedded into the negative plate. The ratio of the total mass of the lithium ribbon to the mass of the negative electrode active material MCMB was 0.08: 1;
(83) assembling: assembling the button capacitor according to the sequence of the negative electrode shell, the negative electrode sheet, the diaphragm, the positive electrode sheet, the gasket, the spring sheet and the positive electrode shell, and adding a proper amount of electrolyte (1mol/L LiPF)6(EC: PC: DEC: 1:1:1V/V/V)) was dropped on the positive electrode sheet and the negative electrode sheet, and the resultant was sealed with a sealer at 150kg/cm2And sealing the pressure to obtain the lithium ion capacitor.
Comparative example 4
The comparative example provides a method for preparing a lithium ion capacitor, comprising the following steps:
(91) preparing a positive plate: weighing Activated Carbon (AC), Lithium Cobaltate (LCO), conductive carbon black and polyvinylidene fluoride (PVDF) according to the mass ratio of 70:20:4:6, grinding the mixture by taking N-methyl pyrrolidone (NMP) as a solvent to form slurry, coating the slurry on a positive current collector, drying the slurry by a vacuum drying box, rolling and punching to obtain the positive plate.
(92) Preparing a negative plate: weighing mesocarbon microbeads (MCMB), conductive carbon black, styrene butadiene rubber emulsion (SBR) and carboxymethyl cellulose (CMC) according to a mass ratio of 91:4:3:2, adding a proper amount of deionized water, grinding to form slurry, coating the slurry on a negative current collector, drying by a vacuum drying oven, rolling, and punching to obtain a negative plate; and placing the lithium strips on different positions of the negative plate, leaving gaps between adjacent lithium strips, assembling each lithium strip into a lithium ion capacitor with the thickness of 55 microns, the length of 3mm and the width of 1mm, and standing for 33h to enable lithium in the lithium strips to be completely embedded into the negative plate. The ratio of the total mass of the lithium ribbon to the mass of the negative electrode active material MCMB was 2: 1;
(93) assembling: assembling the button capacitor according to the sequence of the negative electrode shell, the negative electrode sheet, the diaphragm, the positive electrode sheet, the gasket, the spring sheet and the positive electrode shell, and adding a proper amount of electrolyte (1mol/L LiPF)6(EC: PC: DEC: 1:1:1V/V/V)) was dropped on the positive electrode sheet and the negative electrode sheet, and the resultant was sealed with a sealer at 150kg/cm2And sealing the pressure to obtain the lithium ion capacitor.
Experimental example 1
The lithium ion capacitors obtained in examples 1 to 5 and comparative examples 1 to 4 were subjected to cycle performance tests at 25 ℃ under conditions of 0.05A/g, 0.1A/g, 0.2A/g, 0.5A/g, 1A/g, 2A/g, 2.0 to 4.3V, and the results are shown in Table 1. The lithium ion capacitors obtained in examples 1 to 5 and comparative examples 1 to 4 were subjected to a rate capability test, and the results are shown in fig. 1.
TABLE 1 results of cycle performance test of lithium ion capacitors obtained in examples 1 to 5 and comparative examples 1 to 4
As can be seen from table 1, in the lithium ion capacitor assembled by using MCMB without lithium intercalation as a negative electrode active material and activated carbon as a positive electrode active material in comparative example 1, the specific discharge capacity at 0.05A/g was only 12.6mAh/g, and the specific discharge capacity at 1A/g was already reduced to 0mAh/g, so that it can be seen that lithium intercalation into the negative electrode is a very necessary step in the lithium ion capacitor preparation process.
In comparative example 2, the lithium ion capacitor in which the negative electrode active material MCMB was lithium-inserted at mLi/MCMB of 0.08 and the activated carbon was used as the positive electrode active material had a specific discharge capacity of 61.0mAh/g at 0.05A/g and a capacity retention rate of 40.8% at 1A/g. Compared with comparative example 1, after the negative electrode is subjected to lithium intercalation treatment, the discharge specific capacity and rate performance of the obtained lithium ion capacitor are remarkably improved, but the discharge specific capacity and rate performance are still to be further enhanced.
In comparative example 3, activated carbon and lithium cobaltate (mass ratio 20:70) are used together as the positive electrode active material, and meanwhile, the negative electrode active material MCMB is embedded with lithium in a ratio of mLi/mMCMB of 0.08, so that the specific discharge capacity of the obtained lithium ion capacitor is remarkably reduced at 1A/g and 2A/g, and the capacity retention rate at 2A/g is only 24.6%, which indicates that the rate capability of the lithium ion capacitor obtained in comparative example 3 is relatively poor.
Likewise, in comparative example 4, lithium intercalation was performed with mLi/mMCMB of 2 for the negative electrode active material MCMB; meanwhile, in the positive electrode active material, the active carbon and the lithium cobaltate are doped (mass ratio is 70:20), the discharge specific capacity of the obtained lithium ion capacitor is obviously reduced at 1A/g and 2A/g, and the capacity retention rate at 2A/g is only 20.0%, which shows that the rate performance of the lithium ion capacitor obtained in the comparative example 4 is relatively poor.
In examples 1 to 4, the negative electrode active material MCMB was intercalated with lithium at mLi/MCMB of 0.08, while the positive electrode active material was doped with lithium cobaltate and activated carbon, and the negative electrode was intercalated indirectly by standing for a certain period of time and electrochemical activation during charge and discharge cycles, thereby achieving a high-efficiency lithium intercalation effect of positive and negative electrode double intercalation. In examples 1 to 4, the doping amounts of lithium cobaltate (based on the proportion of lithium cobaltate in the positive electrode active material) were: the energy density of the lithium ion capacitor can be remarkably improved by utilizing the redox mechanism of lithium cobaltate, wherein 5.6% of example 1, 11.1% of example 2, 16.7% of example 3 and 22.2% of example 4 are used. As can be seen from fig. 1 and table 1, as the doping amount of Lithium Cobaltate (LCO) increases, the specific discharge capacity of the lithium ion capacitor gradually increases, and meanwhile, the rate capability also significantly increases. The 5.6% doped lithium cobaltate (example 1) lithium ion capacitor has a discharge specific capacity of 68.5mAh/g at 0.05A/g and a capacity retention rate of 49.1% at 1A/g; the lithium ion capacitor doped with 22.2% lithium cobaltate (example 4) had a specific discharge capacity of 82.9mAh/g at 0.05A/g and a capacity retention rate of 61.2% at 1A/g. However, Lithium Cobaltate (LCO) doped too much has a certain suppression effect on rate performance although the energy density continues to increase. As shown in comparative example 3, the doping amount was 77.8%, the specific discharge capacity at 0.05A/g was 112.4mAh/g, and the capacity retention rate at 2A/g was 24.6%. Therefore, the high rate performance of the lithium ion capacitor is mainly derived from an electric double layer quick response mechanism of the activated carbon, and when Lithium Cobaltate (LCO) is doped too much, the high specific surface area of the activated carbon is inhibited, so that the exertion of the electric double layer mechanism of the activated carbon is influenced to a certain extent, and the rate performance of the activated carbon is finally reduced.
In example 5, the negative electrode active material MCMB was intercalated with lithium at mLi/MCMB of 0.08, and the positive electrode active material was doped with the ternary material NCM532 and activated carbon, and the negative electrode was intercalated indirectly by standing for a certain period of time and electrochemical activation during charge and discharge cycles, thereby achieving a high-efficiency lithium intercalation effect of positive and negative electrode double intercalation. The doping amount of the nickel cobalt lithium manganate (based on the proportion of the nickel cobalt lithium manganate in the positive electrode material) is 22.2%. Because the ternary material NCM532 has higher specific capacity than lithium cobaltate, example 5 has higher specific capacity and rate capability than example 4 at the same doping amount. The specific discharge capacity at 0.05A/g is 91.0mAh/g, and the capacity retention rate at 1A/g is 61.8%
Experimental example 2
BET tests were carried out on Activated Carbon (AC), Lithium Cobaltate (LCO) and the positive electrode active materials of examples 1 to 4, respectively, and the results were that the Activated Carbon (AC) was 1563.9m2(g) Lithium Cobaltate (LCO) 0.46m2(g) ternary material NCM532 is 0.65m2(ii) in terms of/g. After the active carbon is doped with lithium cobaltate and ternary materials with different amounts, the specific surface areas are respectively as follows: example 1 (5.6% doping) 1528.0m2The amount of the catalyst used in example 2 (11.1%) was 1413.5m2The amount of the catalyst used in example 3 (16.7%) was 1370.3m2Example 4 (22.2%) is 1205.4m2The amount of the catalyst used in example 5 (22.2%) was 1306.2m2The amount of the catalyst per gram and the amount of the catalyst in comparative example 3 (77.8%) were 349.5m2/g。
It can be seen that, as the doping amount of lithium cobaltate increases, the specific surface area of the mixture of the activated carbon and the lithium cobaltate gradually decreases, and a slight decrease in the specific surface area has a small influence on the overall performance of the positive electrode active material, and at this time, the double electric layer reaction mechanism and the redox mechanism jointly exert a synergistic effect, so that the energy density and the rate capability of the lithium ion capacitor gradually increase. However, when the doping amount reaches 77.8% (comparative example 3), the specific surface area of the mixture of the activated carbon and the lithium cobaltate is greatly reduced, which has already severely restricted the exertion of the electric double layer mechanism in the activated carbon and has a certain inhibition effect on the exertion of the rate capability. Therefore, the rate retention of the lithium ion capacitor obtained in comparative example 3 is greatly reduced compared to example 3. According to the results, the energy density and rate capability are remarkably improved by doping lithium cobaltate in a proper amount. In addition, the energy density and rate capability can be improved by doping the ternary material NCM532 with a proper amount.
From the above results, it can be seen that in the embodiment of the present invention, the mixture of the activated carbon and the positive electrode material of the lithium ion battery is used as the positive electrode active material, the carbon material is used as the negative electrode active material, and the lithium is pre-embedded in the negative electrode active layer, so that the positive electrode and negative electrode dual-embedding effect is achieved, and the energy density and the rate capability of the obtained lithium ion capacitor are both significantly improved, and the lithium ion capacitor has excellent electrochemical performance.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (10)
1. A lithium ion capacitor comprises a positive electrode, a negative electrode and a diaphragm, wherein the positive electrode and the negative electrode are oppositely arranged, the diaphragm is arranged between the positive electrode and the negative electrode, the positive electrode comprises a positive electrode current collector and a positive electrode active layer combined on the surface of the positive electrode current collector, and the positive electrode active layer comprises a positive electrode active material; the negative electrode comprises a negative electrode current collector and a negative electrode active layer combined on the surface of the negative electrode current collector, and the negative electrode active layer comprises a carbon material, and is characterized in that the positive electrode active material comprises a mixture of activated carbon and a positive electrode material of a lithium ion battery; the negative electrode active layer is a lithium pre-intercalated negative electrode active layer.
2. The lithium ion capacitor according to claim 1, wherein the mass ratio of the activated carbon to the lithium ion battery positive electrode material is (1-30): 1.
3. The lithium ion capacitor according to claim 1, wherein the lithium ion battery positive electrode material is selected from at least one of lithium composite metal oxide, lithium sulfur composite, and lithium polymer.
4. The lithium ion capacitor according to claim 3, wherein the lithium composite metal oxide is selected from LiMO2、LiNiaX1-aO2、LiNibMncCo1-b-cO2、LiYdMn2-dO4、LiFePO4、Li3V2(PO4)3At least one of;
wherein, LiMO2In the formula, M is Co, Ni, Mn, Cu or Fe;
LiNiaX1-aO2wherein X is Co, Mn, Cu, Al, Mg, Fe, La, V, Zn or Cr, and 0<a<1；
LiNibMncCo1-b-cO2Middle, 0<b<1，0<c<1；
LiYdMn2-dO4In which Y is Ni, Co or Al, and 0<d<1。
5. The lithium ion capacitor according to any one of claims 1 to 4, wherein the mass of the positive electrode active material accounts for 70 to 95% of the mass of the positive electrode active layer, based on 100% of the total mass of the positive electrode active layer; and/or
The mass of the negative electrode active material accounts for 80-95% of the mass of the negative electrode active layer by taking the total mass of the negative electrode active layer as 100%.
6. The lithium ion capacitor according to any one of claims 1 to 4, wherein the carbon material is at least one selected from graphite, hard carbon, soft carbon, mesocarbon microbeads, and silicon carbon material.
7. The preparation method of the lithium ion capacitor is characterized by comprising the following steps of:
providing a positive electrode, wherein the positive electrode comprises a positive electrode current collector and a positive electrode active layer combined on the surface of the positive electrode current collector, the positive electrode active layer comprises a positive electrode active material, and the positive electrode active material comprises a mixture of active carbon and a positive electrode material of a lithium ion battery;
providing a negative electrode, wherein the negative electrode comprises a negative electrode current collector and a negative electrode active layer combined on the surface of the negative electrode current collector, the negative electrode active layer comprises a carbon material, and the negative electrode active layer is subjected to pre-lithium intercalation treatment;
stacking or winding the anode, the diaphragm and the cathode, adding electrolyte, and packaging to obtain the lithium ion capacitor;
the method for pre-embedding lithium into the negative active layer comprises the following steps: and providing a lithium tape, arranging the lithium tape on the surface of one side of the negative active layer, which is far away from the negative current collector, and standing for 24-48 h.
8. The method according to claim 7, wherein the number of the lithium strips is two or more, and when the lithium strips are disposed on the surface of the negative electrode active layer, a gap is left between two adjacent lithium strips.
9. The production method according to claim 7, wherein the mass ratio of the total mass of the lithium ribbon to the carbon material is (0.01-1): 1.
10. The method of any one of claims 7 to 9, wherein each of the lithium strips has a thickness of 25 μm to 75 μm, a length of 1mm to 8mm, and a width of 0.5mm to 2 mm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN113921291A (en) * | 2021-09-30 | 2022-01-11 | 北京蒙京石墨新材料科技研究院有限公司 | Positive pole piece and lithium ion capacitor |
| CN114597077A (en) * | 2022-03-21 | 2022-06-07 | 山东大学 | Application of pre-lithiated carbon negative electrode material in sodium ion capacitor and potassium ion capacitor |
| CN115231548A (en) * | 2022-09-20 | 2022-10-25 | 中国科学院山西煤炭化学研究所 | High-capacity modified natural polymer-based hard carbon material and preparation and application thereof |
| CN115703651A (en) * | 2021-08-16 | 2023-02-17 | 上海锂凰科技有限公司 | Oxide type lithium ion battery cathode material based on metal containing high-valence variable valence state and preparation method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN115703651A (en) * | 2021-08-16 | 2023-02-17 | 上海锂凰科技有限公司 | Oxide type lithium ion battery cathode material based on metal containing high-valence variable valence state and preparation method thereof |
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| CN114597077A (en) * | 2022-03-21 | 2022-06-07 | 山东大学 | Application of pre-lithiated carbon negative electrode material in sodium ion capacitor and potassium ion capacitor |
| CN114597077B (en) * | 2022-03-21 | 2023-09-05 | 山东大学 | Application of pre-lithiated carbon negative electrode material in sodium ion capacitor and potassium ion capacitor |
| CN115231548A (en) * | 2022-09-20 | 2022-10-25 | 中国科学院山西煤炭化学研究所 | High-capacity modified natural polymer-based hard carbon material and preparation and application thereof |
| CN115231548B (en) * | 2022-09-20 | 2023-01-13 | 中国科学院山西煤炭化学研究所 | High-capacity modified natural polymer-based hard carbon material and preparation and application thereof |
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