CN113488659B - Negative current collector complex, preparation method thereof and lithium metal battery - Google Patents
Negative current collector complex, preparation method thereof and lithium metal battery Download PDFInfo
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- 229910052744 lithium Inorganic materials 0.000 title claims abstract description 117
- 238000002360 preparation method Methods 0.000 title claims abstract description 7
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims abstract description 128
- 239000010949 copper Substances 0.000 claims abstract description 124
- 229910052802 copper Inorganic materials 0.000 claims abstract description 121
- 229910052751 metal Inorganic materials 0.000 claims abstract description 106
- 239000002184 metal Substances 0.000 claims abstract description 106
- 229920006254 polymer film Polymers 0.000 claims abstract description 62
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims abstract description 37
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- 239000004698 Polyethylene Substances 0.000 claims description 4
- 239000004205 dimethyl polysiloxane Substances 0.000 claims description 4
- 229920000435 poly(dimethylsiloxane) Polymers 0.000 claims description 4
- 229920000573 polyethylene Polymers 0.000 claims description 4
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- 238000005096 rolling process Methods 0.000 claims description 3
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- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 17
- 229910001416 lithium ion Inorganic materials 0.000 description 17
- 230000000052 comparative effect Effects 0.000 description 11
- 210000001787 dendrite Anatomy 0.000 description 9
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 239000011149 active material Substances 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 210000004027 cell Anatomy 0.000 description 2
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/64—Carriers or collectors
- H01M4/66—Selection of materials
- H01M4/668—Composites of electroconductive material and synthetic resins
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/139—Processes of manufacture
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/64—Carriers or collectors
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- H01M4/661—Metal or alloys, e.g. alloy coatings
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- H—ELECTRICITY
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- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/64—Carriers or collectors
- H01M4/66—Selection of materials
- H01M4/665—Composites
- H01M4/667—Composites in the form of layers, e.g. coatings
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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
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Abstract
The invention relates to the field of lithium batteries, in particular to a negative current collector complex and a preparation method thereof, and a lithium metal battery. The negative current collector complex comprises a negative electrode and a current collector, the negative electrode is a lithium metal layer, the current collector comprises a polymer film, copper metal areas are arranged on the side faces of the two sides of the polymer film, a copper metal layer is arranged on the copper metal areas, the lithium metal layer is attached to one side, away from the polymer film, of the copper metal layer, the area of the copper metal layer is 20-70% of the area of the polymer film, and the size of the lithium metal layer is overlapped with that of the polymer film. The lithium metal battery of this application adopts above-mentioned mass flow body, when having improved lithium metal battery's energy density, has also restrained the inhomogeneous lithium deposit of negative pole surface production in battery charging process, and then has improved the cycle life of battery.
Description
Technical Field
The invention relates to the field of lithium batteries, in particular to a negative current collector complex, a preparation method thereof and a lithium metal battery.
Background
Lithium batteries are generally classified into lithium ion batteries and lithium metal batteries, and each of the constituent elements thereof includes a positive electrode, a negative electrode, and a current collector disposed corresponding to the positive electrode and the negative electrode. The working principle of the lithium battery is that the charging and discharging of the battery are realized by the back-and-forth insertion and de-insertion of lithium ions between the anode and the cathode. Because the conductivity of the active materials adopted by the positive and negative electrodes of the battery is poor, a current collector needs to be arranged on the electrode to collect the current generated by the active materials, and the conductivity of the electrode is improved.
The anode of the lithium ion battery usually adopts lithium-containing transition metal oxide, and takes aluminum foil as a current collector; the negative electrode of the lithium ion battery adopts carbon materials such as graphite, and the like, and uses copper foil as a current collector. The lithium metal battery adopts lithium metal as a negative electrode material, copper foil as a current collector, and the lithium metal is rolled on the copper foil to form a negative electrode. The specific capacity of the commercial graphite negative electrode is about 360mAh/g, which is much lower than the specific capacity of lithium metal, 3870mAh/g, so that the lithium metal battery becomes the main development direction of the lithium battery in the future.
But using the "dead weight" percentage of the metal current collector (e.g., copper for the negative electrode) reduces the energy density of the lithium metal battery. Therefore, weight reduction of the current collector becomes an important approach to further increase the energy density. Theoretically, since lithium metal conducts electrons well (the conductivity of Li is 1.1 × 10)5Scm-1Cu of 5.96x105Scm-1) Thus, the Cu current collector may be completely removed. However, complete removal of the Cu substrate presents many challenges, such as non-uniformity of the surface leading to non-uniform exfoliation and/or deposition of Li and the local presence of large currents at the connections, leading to significant increases in local temperature. In addition, lithium can become particulate during cycling, greatly reducing its electronic conductivity. In addition, the lithium metal battery is easy to generate uneven lithium deposition and form dendrite on the surface of the lithium metal negative electrode in the charging process, so that the charging cycle life of the lithium battery is reduced on one hand; on the other hand, under extreme circumstances, the dendrites may even puncture the separator causing a short circuit in the battery.
Disclosure of Invention
The application provides a negative current collector complex body, a preparation method thereof and a lithium metal battery.
In a first aspect, the application provides a negative current collector complex body, the negative current collector complex body includes negative pole and current collector, the negative pole is the lithium metal layer, the current collector includes the polymer film, all be provided with the copper metal district on the side of polymer film both sides, be provided with the copper metal layer on the copper metal district, the lithium metal layer laminating keeps away from one side of polymer film in the copper metal layer, just the area of copper metal layer is 20 ~ 70% of polymer film area, the lithium metal layer coincides with the polymer film.
In the application, the lithium metal can be used as a negative electrode of a battery and also has the function of a current collector; the contrast adopts traditional copper foil as the mass flow body, and this application adopts the polymer film as the substrate to copper metal is the transition layer, fixes the lithium metal layer at last at the negative pole mass flow body's that the surface formed complex body structure, can be when improving energy density, reduce the inhomogeneous lithium deposition phenomenon on the lithium metal negative pole.
After a great deal of research work by the inventors, it is found that the reason for the above effect may be that, using a conventional copper foil current collector, the lithium metal deposition during the charging process of the lithium battery generates a compressive stress, and the compressive stress may cause the formation of a lithium ion concentration gradient on the surface of the lithium metal negative electrode, thereby accelerating the formation of dendrites. The copper metal layer that polymer film surface deposition obtained in this application can produce the unstability fold under compressive stress to form the ripple architecture, thereby release the compressive stress that lithium deposit produced, and then reduce the inhomogeneous lithium deposit that leads to because of compressive stress, keep the active lithium content of negative pole, finally, improve the cycle life of battery.
In addition, the copper metal layer can provide deposition sites for lithium ions in the charging process on the premise of not obviously increasing the weight of the current collector, so that the phenomenon of uneven deposition of a lithium metal negative electrode and even lithium metal stripping is reduced; secondly, the copper metal area can also enhance the heat dissipation performance and the electric conductivity of the negative current collector; finally, the poor welding performance of lithium is not favorable for welding and fixing the negative current collector and the battery tab, so that the copper can compensate the welding performance of the negative current collector.
In addition, through the distribution structure who designs the copper metal layer, can also with electron or electric current from utmost point ear department disperse to each corner of whole negative pole piece fast evenly, for the self-supporting lithium metal negative pole of no copper mass flow body, can make the battery operation more stable, cycle life obtains promoting, can realize the lithium metal battery of bigger area and bigger capacity.
Preferably, the polymer film is one of a polyethylene film, a polypropylene film, a polyethylene terephthalate film and a polydimethylsiloxane film.
The polyethylene film, the polyethylene terephthalate film, the polydimethylsiloxane film and other polymer films have certain flexibility, and when the area percentage of the copper metal layer is lower than 40%, the copper metal layer can generate unstable wrinkles under compressive stress, and the generated wrinkles are enough to inhibit dendritic crystals.
Preferably, the area of the copper metal layer is 30-40% of the area of the polymer film.
By adopting the area ratio, the formation of dendrites is inhibited and the cycle life of the battery is improved on the premise of being beneficial to reducing the quality of the inactive substance current collector and improving the energy density of the battery. The reason for this may be that increasing the current collecting area of copper provides more deposition sites for lithium ions, promoting more uniform lithium deposition, and thus improving the cycle life of the battery. Too small an area of copper is not good for improving cycle life and collecting current is not uniform enough. On the contrary, too much copper is not favorable for reducing weight, is favorable for fully releasing stress, and reduces the mass of the current collector and the energy density of the battery. And the proper area ratio of copper to lithium is adopted, so that the balance between the energy density and the cycle life of the battery is favorably kept.
Preferably, the surface roughness index of the copper metal layer is 2-4 μm.
By adopting the copper metal area with the surface roughness, the uniformity of lithium deposition is further promoted under the condition that the current collecting area of the copper metal area is not increased. The reason may be that the surface with high roughness further increases the specific surface area, provides more deposition sites for the deposition of lithium ions, further reduces the generation of dendrites, and improves the cycle life of the battery; and too high roughness reduces the mechanical strength of copper, forms more defects and is not beneficial to uniform deposition of lithium ions.
Preferably, the plurality of copper metal regions are arranged at intervals along the length direction of the polymer film, and two ends of the copper metal region are arranged along the width direction of the polymer film.
By adopting the technical scheme, the copper metal layers arranged at intervals are beneficial to forming more uniform lithium deposition, the generation of dendritic crystals is reduced, and the cycle life of the battery is improved. The reason may be that, under the same copper metal area, the distribution mode is favorable for setting more copper metal layers which are uniformly distributed, so that the lithium deposition stress is promoted to be uniformly dispersed on each copper metal layer, the stress is fully released, the nonuniform diffusion of lithium ions is favorably inhibited, and the generation of dendritic crystals is reduced; ultimately, the cycle life of the battery is improved.
Preferably, the total thickness of the current collector is 5-10 μm, and the thickness of the copper metal layer is 0.5-2 μm.
By adopting the technical scheme, the thickness of the current collector is reduced, so that the quality of the current collector is favorably reduced, and the energy density of the battery is improved.
In a second aspect, the present application provides a method for preparing a negative current collector complex of a lithium metal battery, comprising the steps of: s1, preparing a shielding object according to the shape of the copper metal area, covering the shielding object on the surface of the polymer film to ensure that the exposed part is matched with the shape of the copper metal area, preparing the copper metal layer by using an evaporation or sputtering method, and removing the shielding object to prepare a current collector;
and S2, rolling the lithium sheet on a current collector to form a lithium metal layer, and obtaining the negative electrode current collector composite.
By adopting the technical scheme, when the copper metal layer is prepared, the non-copper metal area of the polymer film is partially shielded by shielding materials such as release paper or silica gel, and the copper metal area is exposed, so that the preparation of the copper metal layer can be carried out, and the forming of the copper metal layer with the required shape and size is ensured.
In a third aspect, the present application provides a lithium metal battery to which the negative electrode current collector composite of any one of the above is applied.
Compared with the lithium metal battery using the traditional current collector, the lithium metal battery prepared by the negative current collector complex has the advantage of high energy density, and simultaneously inhibits the problem of lithium dendrite caused by uneven deposition of lithium in the charging process, thereby having longer cycle life.
In summary, the present application has the following beneficial effects:
1. the mass flow body in this application, through the copper metal layer that sets up certain area proportion on polymer rete surface, compare with traditional mass flow body, is showing the quality that has reduced the mass flow body to reduce the proportion of mass flow body in the battery, and then improved lithium metal battery's energy density. Because the polymer film has flexibility, the pressure stress generated by lithium ion deposition enables copper to generate folds of wave stripes, and the stress can be effectively released; thereby being beneficial to improving the cycle life and the energy density of the battery.
2. The mass flow body in this application, through the regulation and control have flexible polymer film and the proportion of surperficial copper metal layer, the compressive stress that makes the lithium ion deposit produce can let the mass flow body produce the fold of sufficient wave stripe, effective release stress to effectively restrain dendritic crystal's formation, and then improve battery cycle life.
3. The distribution structure of the copper metal layer of mass flow body in this application can be with electron or electric current from utmost point ear department disperse whole negative pole piece each corner fast uniformly, for the self-supporting lithium metal negative pole of no copper mass flow body, can make the battery operation more stable, and cycle life obtains promoting, can realize the lithium metal battery of bigger area capacity more.
4. This application adopts the high copper metal layer of roughness, and its surface is formed with a large amount of micropores, very big increase copper metal district and lithium ion's area of contact, reduced local current density, provided sufficient deposit site, when improving lithium deposition homogeneity, increased the mechanical engagement on active lithium and copper surface, reducible lithium peels off in the circulation in-process and drops, effectively strengthens the cycle life of battery.
Drawings
Fig. 1 is a schematic view of a cross-sectional structure of a negative electrode current collector complex in example 1 of the present application;
fig. 2 is a schematic view of the distribution of the copper metal layer of the negative electrode current collector on the surface of the polymer film in example 1 of the present application;
fig. 3 is a schematic view of the distribution of the copper metal layer of the negative electrode current collector on the surface of the polymer film in example 7 of the present application;
fig. 4 is a schematic view of the distribution of the copper metal layer of the negative electrode current collector on the surface of the polymer film in example 8 of the present application;
fig. 5 is a schematic view of the distribution of the copper metal layer of the negative electrode current collector on the surface of the polymer film in example 9 of the present application.
1. A negative current collector complex; 2. a negative electrode; 21. a lithium metal layer; 3. a negative current collector; 31. a polymer film; 32. a copper metal region; 33. a copper metal layer.
Detailed Description
In the following examples, a soft-package lithium metal battery was used, wherein the positive electrode material of the battery was NCM622, and the electrolyte was 1M LiPF6/FEC-DEC (1:1 Vol%), separator regular PP, cell capacity 3 Ah.
Examples
Example 1, a lithium metal battery includes a positive electrode, an aluminum foil (current collector of the positive electrode), a separator, and a negative electrode current collector complex.
As shown in fig. 1, the negative electrode current collector complex includes a negative electrode and a current collector. The negative electrode is a lithium metal layer, the current collector comprises a polymer film, copper metal areas are arranged on the side faces of two sides of the polymer film, a copper metal layer is arranged on the copper metal areas, the lithium metal layer is attached to one side, far away from the polymer film, of the copper metal layer, the lithium metal layer is overlapped with the polymer film in size, and the current collector is prepared according to the following method:
s1, cutting out a release paper film according to the shape of the copper metal area, covering the release paper film on the surface of a PET (polyethylene terephthalate) film, and enabling the exposed part to be matched with the shape of the copper metal area to obtain a semi-finished product film; then placing the semi-finished film in a vacuum magnetron sputtering device, taking copper as a target material, depositing the copper on two sides of the semi-finished film to obtain a copper metal layer, and tearing off the release paper film to obtain a current collector;
and S2, rolling lithium sheets on the surfaces of the copper metal layers on the two sides of the current collector to form a lithium metal layer (negative electrode) so as to obtain a negative electrode current collector composite.
As shown in fig. 2, the area of the copper metal layer in the current collector is 40% of the area of the polymer film; the surface roughness index of the copper metal layer is 3 mu m; the two ends of the copper metal layer are arranged along the width direction of the polymer film, and the copper metal layer is arranged at intervals along the length direction of the polymer film. In addition, the total thickness of the current collector is 8 μm, and the thickness of the copper metal layer is 0.5 μm; the thickness of the lithium metal layer was 30 μm.
Example 2, a lithium metal battery, was different from example 1 in that the area of the copper metal layer in the current collector was 30% of the area of the polymer film.
Example 3, a lithium metal battery, was different from example 1 in that the area of the copper metal layer in the current collector was 20% of the area of the polymer film.
Example 4, a lithium metal battery, was different from example 1 in that the area of the copper metal layer in the current collector was 50% of the area of the polymer film.
Example 5, a lithium metal battery, was different from example 1 in that the surface roughness index of the copper metal layer in the current collector was 0.5 μm.
Example 6, a lithium metal battery, was different from example 1 in that the surface roughness index of the copper metal layer in the current collector was 5 μm.
Example 7, a lithium metal battery, as shown in fig. 3, is different from example 1 in that both ends of a copper metal region in a current collector are disposed along a length direction of a polymer film, and the copper metal regions are spaced apart along a width direction of the polymer film.
Example 8, a lithium metal battery, as shown in fig. 4, is different from example 1 in that one copper metal region is provided in a current collector, and both ends of the copper metal region are provided in the width direction of a polymer film.
Example 9, a lithium metal battery, as shown in fig. 5, is different from example 1 in that one copper metal region is provided in a current collector, and both ends of the copper metal region are provided along the length direction of a polymer film.
Examples 10 to 11 are lithium metal batteries, which are different from example 1 in that a polyethylene film and a polydimethylsiloxane film are used as polymer films of a current collector.
Example 12, a lithium metal battery, different from example 1, in that the total thickness of the current collectors was 10 μm, and the thickness of the copper metal layer was 1 μm; the thickness of the lithium metal layer was 30 μm.
Comparative example
Comparative example 1, a lithium metal battery, differs from example 1 in that the area of the copper metal layer in the current collector is 80% of the area of the polymer membrane.
Comparative example 2, a lithium metal battery, is different from example 1 in that the area of the copper metal layer in the current collector is 10% of the area of the polymer film.
Comparative example 3, a lithium metal battery, differs from example 1 in the no current collector design, using a self-supporting lithium metal negative electrode.
Comparative example 4, a lithium metal battery, was different from example 1 in that lithium metal was used as a negative electrode and copper foil having a thickness of 8 d was used as a negative electrode current collector.
Performance test
Test 1: preparing a lithium metal battery cycle performance test sample: the lithium metal batteries of examples 1 to 12 and comparative examples 1 to 4 were used as test samples.
The test method comprises the following steps: (1) performing charge-discharge cycle on the test sample by adopting a charge rate of 0.33C/0.33C, and recording the cycle number of the battery when the cycle is performed until the capacity retention rate is 80%, wherein the test result is shown in Table 1;
(2) the cells were discharged, the energy density was calculated and recorded, and the test results are shown in table 1.
TABLE 1 lithium Metal Battery cycling Performance test results
And (3) analyzing test results:
(1) by combining examples 1-12 with comparative examples 3-4 and combining table 1, it can be seen that comparative example 3 uses pure lithium metal as a negative electrode and does not adopt a current collector design, and comparative example 4 uses lithium metal as a negative electrode and copper foil as a current collector; in examples 1 to 12, the copper metal layer and the lithium metal layer are sequentially formed on the surface of the polymer film layer, and the prepared negative electrode current collector complex can significantly improve the cycle life of the battery and the like. The reason for this may be that the deposition of lithium metal may generate compressive stress, which may lead to the formation of a lithium ion concentration gradient on the surface of the lithium metal negative electrode, thereby promoting the generation of dendrites. The copper metal layer that polymer film surface deposition obtained can produce the unstability fold under compressive stress in this application to form ripple architecture, thereby release the compressive stress that lithium deposit produced, and then reduce the inhomogeneous lithium deposit that leads to because of compressive stress, reduce the loss that active lithium led to the fact because of dendritic crystal growth, finally make lithium metal battery's cycle life improve.
(2) It can be seen from the combination of examples 1 to 12 and comparative examples 1 to 2 and table 1 that, compared with comparative examples 1 to 2, the area of the copper metal layer in the current collectors of examples 1 to 12 is 20 to 70% of the area of the polymer film, so that the current collectors have higher cycle life and energy density. Preferably, compared with examples 3 to 4, the area of the copper metal layer in the current collectors of examples 1 to 2 is 30 to 40% of the area of the polymer film, and the battery cycle life and energy density performance are more excellent.
The reason for the above phenomenon may be that, by adopting the above area ratio, the copper current collecting area is increased, more deposition sites are provided for lithium ions, lithium deposition is promoted to be more uniform, and thus the cycle life of the battery is improved. Too small an area of copper is detrimental to improving cycle life and to providing a current that is not uniform enough. On the contrary, the copper metal layer with too much proportion is not favorable for reducing the weight, and reducing the mass of the current collector and the energy density of the battery. And the proper area ratio of copper to lithium is adopted, so that the balance between the energy density and the cycle life of the battery is favorably kept.
(3) When the examples 1 and 5 to 6 are combined and table 1 is combined, it can be seen that the surface roughness indexes of the molten metal layers in the examples 5 to 6 are 0.5 μm and 5 μm, respectively; the roughness index of example 1 was 3 μm, and the cycle life of the battery of example 1 was longer than that of examples 5 to 6. The reason for this may be that the copper metal layer with surface roughness is beneficial to improving the specific surface area thereof under the condition of the same current collector area, providing more deposition sites for the deposition of lithium ions, promoting the uniformity of lithium deposition, further reducing the generation of dendrites, increasing the mechanical engagement of active lithium and copper surface, reducing the peeling and falling of lithium in the circulation process, and effectively enhancing the cycle life of the battery.
(4) When example 1 is combined with examples 7 to 9 and table 1 shows that the cycle life of the battery of example 1 is longer than that of examples 7 to 9; as shown in fig. 2, two ends of the copper metal region in example 1 are disposed along the width direction of the polymer film, and a plurality of copper metal regions are disposed at intervals along the length direction of the polymer film; as shown in fig. 3, in the current collector of example 7, two ends of the copper metal region are disposed along the length direction of the polymer film, and the copper metal regions are disposed at intervals along the width direction of the polymer film; as shown in fig. 4, one copper metal region is disposed in the current collector, and both ends of the copper metal region are disposed along the width direction of the polymer film; as shown in fig. 5, one copper metal region is disposed in the current collector, and both ends of the copper metal region are disposed along the length direction of the polymer film.
The reason for the above phenomenon may be that, under the same current collecting area, the above arrangement is favorable for obtaining a greater number of copper metal regions, so that copper metal is uniformly distributed on the polymer film, thereby promoting current to be rapidly transmitted to each region of the negative electrode, reducing the distance of electron transfer in lithium metal as much as possible, and in addition, the soft polymeric layer and the copper metal layer are uniformly spatially distributed, so as to realize sufficient release of stress, be favorable for inhibiting uneven diffusion of lithium ions, and reduce generation of dendrites; ultimately, the cycle life of the battery is improved.
The present embodiment is only for explaining the present application, and it is not limited to the present application, and those skilled in the art can make modifications of the present embodiment without inventive contribution as needed after reading the present specification, but all of them are protected by patent law within the scope of the claims of the present application.
Claims (7)
1. A negative current collector composite characterized by: the negative electrode is a lithium metal layer, the current collector comprises a polymer film, copper metal areas are arranged on the side faces of two sides of the polymer film, a copper metal layer is arranged on the copper metal areas, the lithium metal layer is attached to one side, far away from the polymer film, of the copper metal layer, the area of the copper metal layer is 20-70% of the area of the polymer film, the lithium metal layer and the polymer film are overlapped in size, and the surface roughness index of the copper metal layer is 2-4 mu m.
2. The negative electrode current collector composite according to claim 1, wherein: the polymer film is one of a polyethylene film, a polypropylene film, a polyethylene terephthalate film and a polydimethylsiloxane film.
3. The negative electrode current collector composite according to claim 1, wherein: the area of the copper metal layer is 30-40% of the area of the polymer film.
4. The negative electrode current collector composite according to claim 3, wherein: the copper metal area is provided with a plurality of intervals along the length direction of the polymer film, and two ends of the copper metal area are arranged along the width direction of the polymer film.
5. The negative electrode current collector composite according to claim 1, wherein: the total thickness of the current collector is 5-10 mu m, and the thickness of the copper metal layer is 0.5-2 mu m.
6. A preparation method of the negative electrode current collector composite according to any one of claims 1 to 5, characterized by comprising the steps of:
s1: preparing a shielding object according to the shape of the copper metal area, covering the shielding object on the surface of the polymer film to enable the exposed part to be matched with the shape of the copper metal area, preparing a copper metal layer by using an evaporation or sputtering method, and removing the shielding object to prepare a current collector; s2: and rolling the lithium sheet on a current collector to form a lithium metal layer, thereby obtaining the negative current collector complex.
7. A lithium metal battery, characterized in that: the negative electrode current collector composite according to any one of claims 1 to 5 is used.
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| CN114171718B (en) * | 2021-11-01 | 2024-03-19 | 浙江锋锂新能源科技有限公司 | A method for preparing pole pieces of composite foil current collectors, pole pieces and soft pack batteries |
| CN114122540B (en) * | 2021-11-15 | 2023-06-13 | 电子科技大学 | A temperature detector and its preparation method, lithium battery structure combination |
| CN114188503B (en) * | 2021-12-03 | 2024-06-18 | 珠海冠宇电池股份有限公司 | Battery |
| CN116315090A (en) * | 2023-02-20 | 2023-06-23 | 深圳新宙邦科技股份有限公司 | Lithium ion battery |
| CN116314844B (en) * | 2023-05-22 | 2023-08-08 | 河北海伟电子新材料科技股份有限公司 | Composite metal substrate, composite metal foil, current collector, preparation method and application |
| CN116826025B (en) * | 2023-08-22 | 2023-12-01 | 天津中能锂业有限公司 | Lithium complex and preparation method thereof |
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