阅读说明：本技术 锂基电极和二次锂电池 (Lithium-based electrode and secondary lithium battery ) 是由 张强 程新兵 张健 徐向群 肖也 于 2021-07-27 设计创作，主要内容包括：本发明涉及锂电池技术领域,具体提供一种锂基电极和二次锂电池。所述锂基电极包括锂基片和附着于锂基片至少一表面上的复合膜层；复合膜层中含有有机高分子材料和二维无机片状材料；有机高分子材料和二维无机片状材料呈交替层叠排列的结构；有机高分子材料和二维无机片状材料的质量比为40:60～0.1:99.9；复合膜层的厚度为50nm～20μm。本发明的锂基电极和二次锂电池,复合膜层能将锂基片与外界进行有效的隔绝且具有较强的机械强度,从而可有效抑制以该锂基电极为负极的二次锂电池的锂枝晶生长,并抑制锂基片和电解液的副反应,从而有效提高二次锂电池的安全性能、电极利用率及库伦效率,并改善二次锂电池的循环性能。(The invention relates to the technical field of lithium batteries, and particularly provides a lithium-based electrode and a secondary lithium battery. The lithium-based electrode comprises a lithium substrate and a composite film layer attached to at least one surface of the lithium substrate; the composite film layer contains an organic polymer material and a two-dimensional inorganic flaky material; the organic high molecular material and the two-dimensional inorganic flaky material are in a structure of alternate laminated arrangement; the mass ratio of the organic high polymer material to the two-dimensional inorganic flaky material is 40: 60-0.1: 99.9; the thickness of the composite film layer is 50 nm-20 μm. According to the lithium-based electrode and the secondary lithium battery, the composite film layer can effectively isolate the lithium substrate from the outside and has strong mechanical strength, so that the growth of lithium dendrites of the secondary lithium battery taking the lithium-based electrode as a negative electrode can be effectively inhibited, the side reaction of the lithium substrate and electrolyte is inhibited, the safety performance, the electrode utilization rate and the coulombic efficiency of the secondary lithium battery are effectively improved, and the cycle performance of the secondary lithium battery is improved.)

1. A lithium-based electrode comprising a lithium substrate and a composite film layer attached to at least one surface of the lithium substrate;

the composite film layer contains an organic polymer material and a two-dimensional inorganic flaky material, and the organic polymer material and the two-dimensional inorganic flaky material are in an alternately laminated arrangement structure;

the mass ratio of the organic high polymer material to the two-dimensional inorganic flaky material is 40: 60-0.1: 99.9;

the thickness of the composite film layer is 50 nm-20 mu m.

2. The lithium-based electrode according to claim 1, wherein the two-dimensional inorganic platelet material comprises at least one of graphite, hexagonal boron nitride, black phosphorus, transition metal dichalcogenides, transition metal trichalcogenides, metal phosphorus trichalcogenides, transition metal oxyhalides, metal halides, layered oxides, layered monometallic hydroxides, layered silicates, metal carbides, nitrides, other layered semiconductor materials, natural layered mineral materials.

3. The lithium-based electrode of claim 2, wherein the transition metal dichalcogenide comprises MoS₂、WS₂、WSe₂、NbSe₂、ZrS₂、ZrSe₂、NbS₂、TiS₂、TaS₂、NiSe₂And NbSe₂At least one of;

the transition metal tri-chalcogenides comprise NbX₃、TiX₃And TaX₃Wherein X comprises any one of S, Se, Te;

the metal phosphorus trithionic compound comprises MnPS₃、CdPS₃、NiPS₃And ZnPS₃At least one of;

the transition metal oxyhalide comprises VOCl, CdCOCl, FeOCl, NbO₂F and WO₂Cl₂At least one of;

the metal halide comprises PbI₂、BiI₃、MoCl₂And PbCl₄At least one of;

the layered oxide comprises Bi₂Sr₂CaCu₂O_x、Sr₂Nb₃O₁₀、TiO₂、H₂Ti₃O₇、MnO₂、MoO₃、MgO、WO₃、V₂O₅、LaNbO₄And Bi₄Ti₃O₁₂At least one of;

the layered monometallic hydroxide comprises Ni (OH)₂、Eu(OH)₃At least one of;

the layered siliconThe acid salt comprises (Mg)₃)(Si₂O₅)₂(OH)₂、Ca₂Al(AlSi₃O₁₀)(OH)₂At least one of muscovite and biotite;

the metal carbide comprises WC₂；

The nitride includes C₃N₄；

The other layered semiconductor material comprises GaSe, GaTe, InSe, GeSe, In₂Se₃And Bi₂Se₃At least one of;

the natural layered mineral material comprises at least one of kaolin, montmorillonite, vermiculite, rectorite and layered double hydroxide.

4. The lithium-based electrode according to claim 1, wherein the organic polymer material comprises at least one of polyvinyl alcohol, polyethylene oxide, polytetrafluoroethylene, sodium carboxymethylcellulose, polyurethane, polyacrylonitrile, polymethyl methacrylate, polyvinyl formal, polyvinylidene fluoride-hexafluoropropylene copolymer, perfluorosulfonic acid resin, polyvinyl butyral, and polyvinyl chloride.

5. The lithium-based electrode according to claim 1, wherein the composite film layer further comprises a lithium salt; taking the organic high polymer material as a reference, the lithium salt accounts for 0-50% of the mass of the organic high polymer material;

or, the organic polymer material is doped with lithium ions, and the doping amount of the lithium ions in the organic polymer material is 0-50%.

6. The lithium-based electrode of claim 5, wherein the lithium salt comprises at least one of lithium fluoride, lithium nitride, lithium oxide, lithium hexafluorophosphate, lithium hexafluoroborate, lithium hexafluoroarsenate, lithium perchlorate, lithium biethanate borate, lithium difluorooxalate borate, lithium difluoride xanthimide, and lithium bis (trifluoromethylsulfonyl) imide.

7. The lithium-based electrode of claim 1, wherein the lithium substrate comprises any one of a metallic lithium sheet, a lithium alloy sheet.

8. The lithium-based electrode of claim 1, further comprising a current collector, wherein the lithium substrate is attached to a surface of the current collector.

9. A secondary lithium battery comprising a positive electrode, a negative electrode, a separator provided between the positive electrode and the negative electrode, and an electrolyte occluded in the positive electrode, the negative electrode, and the separator, wherein the negative electrode is the lithium-based electrode according to any one of claims 1 to 8.

10. The lithium secondary battery according to claim 9, wherein the active material of the positive electrode includes any one of lithium iron phosphate, sulfur, oxygen, lithium cobaltate, a nickel-cobalt-manganese ternary material, a nickel-cobalt-aluminum ternary material, and a lithium-rich ternary material.

[ technical field ] A method for producing a semiconductor device

The invention belongs to the technical field of lithium batteries, and particularly relates to a lithium-based electrode and a secondary lithium battery.

[ background of the invention ]

The conventional commercial secondary lithium battery basically takes graphite as a negative active material, but the energy density of the secondary lithium battery is slowly developed and cannot meet the use requirement of a new energy automobile, and the theoretical capacity of a metallic lithium negative electrode is 3860mAh g^-1And the potential is-3.040V (vs. standard hydrogen electrode), so that the lithium metal as the negative electrode is expected to improve the energy density of the secondary lithium battery.

However, lithium metal is prone to generate dendrites in a cycle test of a secondary lithium battery, the dendrites may pierce through a separator to cause a short circuit between an anode and a cathode, and potential safety hazards are large, so that industrialization of the secondary lithium battery based on a lithium metal cathode is hindered.

In order to solve the problem of dendrite of a lithium metal cathode, a layer of antimony-containing lithium phosphate interface protective layer is sputtered on the surface of a copper foil through magnetron sputtering in the prior art, so that uniform deposition of lithium ions can be promoted, long-time circulation stability is realized, but the practicability is low because the magnetron sputtering technology is not suitable for large-scale preparation. In the prior art, a flexible polymer film is adopted to inhibit the growth of dendrites, but the mechanical modulus of the polymer film is low, so that the polymer film cannot adapt to the penetration of the dendrites in the cycle process of a secondary lithium battery under high magnification.

For this reason, it is necessary to explore a new scheme for solving the above-mentioned problems of the lithium secondary battery based on the metallic lithium negative active material and improving the utilization rate and cycle performance of lithium metal.

[ summary of the invention ]

The invention aims to provide a lithium-based electrode, which solves the problems that lithium dendrite is easy to occur when metal lithium is used as a negative electrode active material in the conventional secondary lithium battery.

In order to achieve the technical goal, the embodiment of the invention adopts the following technical scheme:

a lithium-based electrode including a lithium substrate and a composite film layer attached to at least one surface of the lithium substrate;

the composite film layer contains an organic polymer material and a two-dimensional inorganic flaky material, and the organic polymer material and the two-dimensional inorganic flaky material are in an alternately laminated arrangement structure; the mass ratio of the organic high polymer material to the two-dimensional inorganic flaky material is 40: 60-0.1: 99.9;

the thickness of the composite film layer is 50 nm-20 mu m.

In some embodiments, the two-dimensional inorganic platelet material comprises at least one of graphite, hexagonal boron nitride, black phosphorus, transition metal dichalcogenides, transition metal trichalcogenides, metal phosphorus trichalcogenides, transition metal oxyhalides, metal halides, layered oxides, layered monometal hydroxides, layered silicates, metal carbides, nitrides, other layered semiconductor materials, natural layered mineral materials.

In some embodiments, the transition metal dichalcogenide comprises MoS₂、WS₂、WSe₂、NbSe₂、ZrS₂、ZrSe₂、NbS₂、TiS₂、TaS₂、NiSe₂And NbSe₂At least one of;

the transition metal tri-chalcogenides comprise NbX₃、TiX₃And TaX₃Wherein X comprises any one of S, Se, Te;

the metal phosphorus trithionic compound comprises MnPS₃、CdPS₃、NiPS₃And ZnPS₃At least one of;

the transition metal oxyhalide comprises VOCl, CdCOCl, FeOCl, NbO₂F and WO₂Cl₂At least one of;

the metal halide comprises PbI₂、BiI₃、MoCl₂And PbCl₄At least one of;

the layered oxide comprises Bi₂Sr₂CaCu₂O_x、Sr₂Nb₃O₁₀、TiO₂、H₂Ti₃O₇、MnO₂、MoO₃、MgO、WO₃、V₂O₅、LaNbO₄And Bi₄Ti₃O₁₂At least one of;

the layered monometallic hydroxide comprises Ni (OH)₂、Eu(OH)₃At least one of;

the phyllosilicate comprises (Mg)₃)(Si₂O₅)₂(OH)₂、Ca₂Al(AlSi₃O₁₀)(OH)₂At least one of muscovite and biotite;

the metal carbide comprises WC₂；

The nitride includes C₃N₄；

The other layered semiconductor material comprises GaSe, GaTe, InSe, GeSe, In₂Se₃And Bi₂Se₃At least one of;

the natural layered mineral material comprises at least one of kaolin, montmorillonite, vermiculite, rectorite and layered double hydroxide.

In some embodiments, the organic polymer material comprises at least one of polyvinyl alcohol, polyethylene oxide, polytetrafluoroethylene, sodium carboxymethylcellulose, polyurethane, polyacrylonitrile, polymethyl methacrylate, polyvinyl formal, polyvinylidene fluoride-hexafluoropropylene copolymer, perfluorosulfonic acid resin, polyvinyl butyral, polyvinyl chloride.

In some embodiments, the composite film layer further comprises a lithium salt; taking the organic high polymer material as a reference, the lithium salt accounts for 0-50% of the mass of the organic high polymer material;

or, the organic polymer material is doped with lithium ions, and the doping amount of the lithium ions in the organic polymer material is 0-50%.

In some embodiments, the lithium salt comprises at least one of lithium fluoride, lithium nitride, lithium oxide, lithium hexafluorophosphate, lithium hexafluoroborate, lithium hexafluoroarsenate, lithium perchlorate, lithium bis (oxalato) borate, lithium difluoro (oxalato) borate, lithium bis (fluoroxantheimide), and lithium bis (trifluoromethylsulfonyl) imide.

In some embodiments, the lithium substrate sheet comprises any one of a metallic lithium sheet, a lithium alloy sheet.

In some embodiments, the lithium-based electrode further comprises a current collector, and the lithium substrate is attached to a surface of the current collector in a fitting manner.

Another object of the present invention is to provide a lithium secondary battery comprising a positive electrode, a negative electrode, a separator provided between the positive electrode and the negative electrode, and an electrolyte solution occluded in the positive electrode, the negative electrode, and the separator, wherein the negative electrode is the lithium-based electrode described in any one of the above.

In some embodiments, the active material of the positive electrode includes any one of lithium iron phosphate, sulfur, oxygen, lithium cobaltate, nickel cobalt manganese ternary material, nickel cobalt aluminum ternary material, lithium rich ternary material.

The invention has the beneficial effects that:

compared with the prior art, the lithium-based electrode and the secondary lithium battery provided by the embodiment of the invention have the advantages that the composite film layer comprising the organic polymer material and the two-dimensional inorganic sheet material is attached to the surface of the lithium substrate, the organic polymer material and the two-dimensional inorganic sheet material are in a structure of alternately laminated arrangement, wherein the mass ratio of the organic high molecular material to the two-dimensional inorganic flaky material is 40: 60-0.1: 99.9, the thickness of the formed composite film layer is 50 nm-20 mu m, so that the composite film layer can effectively isolate the lithium substrate from the outside and has stronger mechanical strength, thereby effectively inhibiting the growth of lithium dendrite of a secondary lithium battery using the lithium-based electrode as a negative electrode, and inhibiting the side reaction of a lithium substrate and an electrolyte, therefore, the safety performance of the secondary lithium battery is effectively improved, the cycle performance of the secondary lithium battery is improved, and in addition, the electrode utilization rate and the coulomb efficiency of the secondary lithium battery can also be effectively improved.

[ description of the drawings ]

Fig. 1 is a schematic structural view of a lithium-based electrode according to an embodiment of the present invention;

FIG. 2 is a schematic structural view of a lithium-based electrode according to another embodiment of the present invention;

FIG. 3 is a scanning electron micrograph of a lithium-based electrode provided in example 1 of the present invention;

fig. 4 is a scanning electron microscope image of a negative electrode of the lithium-lithium symmetric battery provided in example 1 of the present invention after 200 cycles.

The reference numbers illustrate:

100. a lithium-based electrode;

1. a lithium substrate; 11. a first surface; 12. a second surface;

2. compounding the film layer; 21. a two-dimensional inorganic sheet material; 22. an organic polymer material;

3. and (4) a current collector.

[ detailed description ] embodiments

The invention is further described with reference to the following figures and embodiments. It is to be understood that the described embodiments are merely a few embodiments of the invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Description of professional vocabulary:

electrode utilization rate: the ratio of the remaining capacity of the electrode after the end of the cycle to the capacity of the electrode before the cycle. The secondary lithium battery after circulation is disassembled, and the disassembled electrode is subjected to a stripping experiment, so that the capacity of lithium capable of being stripped is the residual capacity of the electrode.

Fig. 1 and 2 are simplified schematic diagrams of a lithium-based electrode 100 according to an embodiment of the present invention.

Referring to fig. 1, a lithium-based electrode 100 according to an embodiment of the present invention includes a lithium substrate 1 and a composite film layer 2 attached to at least one surface of the lithium substrate 1; the composite film layer 2 contains an organic polymer material 22 and a two-dimensional inorganic flaky material 21, the organic polymer material and the two-dimensional inorganic flaky material are in an alternate laminated arrangement structure, the mass ratio of the organic polymer material 22 to the two-dimensional inorganic flaky material 21 in the composite film layer 2 is 40: 60-0.1: 99.9, and the thickness of the composite film layer 2 is 50 nm-20 μm.

Referring to fig. 1, in some embodiments, a lithium substrate 1 has a first surface 11 and a second surface 12, the first surface 11 and the second surface 12 are opposite to each other, and a composite film layer 2 is attached on the first surface 11 and the second surface 12. Thus, the lithium substrate 1 can be isolated from the outside in all directions, and the growth of lithium dendrites can be suppressed from both surfaces. In some embodiments, the lithium substrate 1 may be a metallic lithium sheet, or a lithium alloy sheet. The lithium alloy sheet may be any one of a lithium indium alloy sheet, a lithium silicon alloy sheet, a lithium tin alloy sheet, a lithium magnesium alloy sheet, a lithium aluminum alloy sheet, and the like.

Referring to fig. 2, in some embodiments, the lithium-based electrode 100 includes a lithium substrate 1, a composite film layer 2 and a current collector 3, the lithium substrate 1 has a first surface 11 and a second surface 12, the first surface 11 and the second surface 12 are opposite, the composite film layer 2 is attached to the first surface 11, and the second surface 12 of the lithium substrate 1 and the current collector 3 are attached to each other. Namely, the lithium substrate 1 can be isolated from the outside only by laminating the composite film layer 2 on the surface of the lithium substrate 1 opposite to the current collector 3, and the growth of lithium dendrites can be effectively inhibited. In some embodiments, the lithium substrate 1 may be a metallic lithium sheet, or a lithium alloy sheet.

In some embodiments, the two-dimensional inorganic sheet material 21 is a nanoscale material. Further preferably, the size of the two-dimensional inorganic platelet material 21 is between 2nm and 1000 nm.

In some embodiments, the two-dimensional inorganic platelet material 21 comprises at least one of graphite, hexagonal boron nitride, black phosphorus, transition metal dichalcogenides, transition metal trichalcogenides, metal phosphorus trichalcogenides, transition metal oxyhalides, metal halides, layered oxides, layered monometal hydroxides, layered silicates, metal carbides, nitrides, other layered semiconductor materials, natural layered mineral materials.

Further, the transition metal IIThe chalcogenide compound comprises MoS₂、WS₂、WSe₂、NbSe₂、ZrS₂、ZrSe₂、NbS₂、TiS₂、TaS₂、NiSe₂And NbSe₂At least one of (1).

Further, the transition metal trithionic compound comprises NbX₃、TiX₃And TaX₃Wherein X comprises any one of S, Se, Te.

Further, the metal phosphorus trithionic compound includes MnPS₃、CdPS₃、NiPS₃And ZnPS₃At least one of (1).

Further, the transition metal oxyhalide includes VOCl, CdCOCl, FeOCl, NbO₂F and WO₂Cl₂At least one of (1).

Further, the metal halide comprises PbI₂、BiI₃、MoCl₂And PbCl₄At least one of (1).

Further, the layered oxide includes Bi₂Sr₂CaCu₂O_x、Sr₂Nb₃O₁₀、TiO₂、H₂Ti₃O₇、MnO₂、MoO₃、MgO、WO₃、V₂O₅、LaNbO₄And Bi₄Ti₃O₁₂At least one of (1).

Further, the layered monometallic hydroxide comprises Ni (OH)₂、Eu(OH)₃At least one of (1).

Further, the layer silicate comprises (Mg)₃)(Si₂O₅)₂(OH)₂、Ca₂Al(AlSi₃O₁₀)(OH)₂At least one of muscovite and biotite.

Further, the metal carbide includes WC₂。

Further, the nitride includes C₃N₄. Further, said C₃N₄Comprising alpha-C₃N₄、c-C₃N₄、p-C₃N₄、g-C₃N₄、β-C₃N₄At least one of (1).

Further, the other layered semiconductor material includes GaSe, GaTe, InSe, GeSe, In₂Se₃And Bi₂Se₃At least one of; the natural Layered mineral material comprises at least one of kaolin, montmorillonite, vermiculite, rectorite and Layered Double Hydroxide (LDH). Still further, the layered double hydroxides include hydrotalcites and hydrotalcite-like compounds.

In some embodiments, the organic polymer material 22 includes at least one of polyvinyl alcohol, polyethylene oxide, polytetrafluoroethylene, sodium carboxymethylcellulose, polyurethane, polyacrylonitrile, polymethyl methacrylate, polyvinyl formal, polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), perfluorosulfonic acid resin, polyvinyl butyral, polyvinyl chloride.

In some embodiments, the composite film layer 2 further contains a lithium salt; the lithium salt accounts for 0-50% of the mass of the organic polymer material 22 based on the organic polymer material 22. Or, the organic polymer material is doped with lithium ions, and the doping amount of the lithium ions in the organic polymer material is 0-50%.

In some embodiments, the lithium salt comprises at least one of lithium fluoride, lithium nitride, lithium oxide, lithium hexafluorophosphate, lithium hexafluoroborate, lithium hexafluoroarsenate, lithium perchlorate, lithium bis (oxalato) borate, lithium difluoro (oxalato) borate, lithium bis (fluoroxantheimide), and lithium bis (trifluoromethylsulfonyl) imide.

In some embodiments, the lithium salt is uniformly dispersed in the organic polymer material 22, and the organic polymer material 22 and the two-dimensional inorganic sheet material 21 are alternately stacked to form the composite film layer 2.

The embodiment of the present invention further provides a method for preparing the lithium-based electrode 100, including the following steps:

(1) the organic polymer material 22 and the two-dimensional inorganic sheet material 21 are provided, and the lithium substrate 1 is also provided.

(2) Mixing the organic high polymer material 22 and the two-dimensional inorganic flaky material 21 to obtain a mixed material.

In some embodiments, any of the lithium salts described above are also provided, as well as a solvent. Further, the organic solvent is any one of acetone and N-methylpyrrolidone. Mixing lithium salt and solvent with organic high molecular material 22 and two-dimensional inorganic flaky material 21 to obtain a mixed material.

(3) And coating the mixture on at least one surface of the lithium substrate 1, so that the mixture forms a composite film layer 2 and is attached to the surface of the lithium substrate 1, thereby obtaining the lithium-based electrode 100.

In some embodiments, the coating method can be knife coating, brush coating, dip coating, flow coating, etc., or can be spray coating, wherein the spray coating includes two methods of general spray coating and thermal spray coating, if the general spray coating is performed, the mixed material contains a solvent, and if the thermal spray coating is performed, the organic polymer material 22 and the two-dimensional inorganic sheet material 21 only need to be dry-mixed.

On the basis, the embodiment of the invention further provides a secondary lithium battery.

Specifically, a secondary lithium battery includes a positive electrode, a negative electrode, a separator, an electrolyte, a battery case, and the like. The battery case is provided with a containing cavity, the positive electrode, the negative electrode, the diaphragm and the electrolyte are contained in the containing cavity, the diaphragm is arranged between the positive electrode and the negative electrode and used for separating the positive electrode and the negative electrode, short circuit caused by direct contact of the positive electrode and the negative electrode is avoided, and meanwhile, the diaphragm is also used for passing lithium ions; the electrolyte is absorbed in the positive electrode, the negative electrode and the separator; the negative electrode is a lithium-based electrode 100 provided by an embodiment of the present invention.

In some embodiments, the negative electrode includes a negative electrode current collector and the lithium-based electrode 100 described above, and the lithium-based electrode 100 is attached to a surface of the negative electrode current collector.

In some embodiments, the positive electrode includes a positive electrode current collector and a positive electrode active layer including a positive electrode active material. In some embodiments, the positive active material includes any one of lithium iron phosphate, sulfur, lithium cobaltate, nickel cobalt manganese ternary material, nickel cobalt aluminum ternary material, and lithium-rich ternary material, and the resulting secondary lithium battery is referred to as a lithium iron phosphate battery, a lithium sulfur battery, a lithium cobaltate battery, a nickel cobalt manganese battery, a nickel cobalt aluminum battery, and a lithium-rich ternary battery, respectively.

In some embodiments, the positive active layer further includes a conductive agent and a binder. For example, the positive active material of the secondary lithium battery is lithium iron phosphate, sulfur, lithium cobaltate, a nickel-cobalt-manganese ternary material, a nickel-cobalt-aluminum ternary material and a lithium-rich ternary material, and the positive active layer comprises a conductive agent and a binder.

In some embodiments, the positive electrode material includes an air positive electrode, active oxygen, and such a secondary lithium battery is referred to as a lithium-air battery.

In order to better illustrate the technical solution of the present invention, the following is further explained by several embodiments.

Example 1

A lithium-based electrode and a method for preparing the same, wherein the method for preparing the lithium-based electrode comprises the following steps:

mixing polyvinylidene fluoride-hexafluoropropylene copolymer with vermiculite sheet [ (Mg)₆)(Si₆Al₂)O₂₀(OH)₄]Mixing materials according to the mass ratio of 3:7, simultaneously adding a proper amount of acetone and lithium bistrifluoromethylsulfonyl imide accounting for 5% of the mass of the polyvinylidene fluoride-hexafluoropropylene copolymer, and uniformly mixing to obtain a mixed material;

and uniformly coating the mixed material on two opposite surfaces of the metal lithium sheet by adopting a blade coating method, controlling the thickness of the coating on each surface of the metal lithium sheet to be 5 mu m, and drying to obtain composite films attached to the two surfaces of the metal lithium sheet, thereby obtaining the lithium-based electrode. The obtained lithium-based electrode was characterized by morphology using a scanning electron microscope, and the results are shown in fig. 3.

As can be seen from fig. 3, a laminated composite film layer is attached to the surface of the lithium metal sheet.

In order to highlight the effect of lithium dendrites, the obtained lithium-based electrodes were assembled into a lithium-lithium symmetric battery. Using LiPF₆(1.0M) -ethylene carbonate/diethyl carbonate (i.e. EC/DEC, volume ratio 1:1) as electrolyte, commercial PP separator.

On a battery tester according to the proportion of 1mA/cm²The obtained lithium-lithium symmetric battery is subjected to a cyclic charge-discharge test by using the current density, after 200 cycles, the lithium-lithium symmetric battery is disassembled, and lithium dendrites on the surface of the lithium-based electrode cannot be observed by naked eyes. After the electrolyte on the surface of the lithium-based electrode was cleaned, the obtained lithium-based electrode was characterized by its morphology using a scanning electron microscope, and the results are shown in fig. 4.

As can be seen from fig. 4, no lithium dendrites were observed under the scanning electron microscope. This indicates that lithium dendrite is not easily generated on the electrode due to the composite film layer attached to the surface of the metal lithium sheet. The composite film layer can effectively inhibit the formation of lithium dendrites.

Example 2

On the basis of the results of the lithium dendrite growth test performed on the lithium-lithium symmetric battery according to example 1, the present example provides a lithium-based electrode, a method for preparing the same, and a secondary lithium battery, wherein the method for preparing the lithium-based electrode includes the following steps:

mixing polyethylene oxide and black flakes according to the mass ratio of 1:9, simultaneously adding a proper amount of acetone and lithium bis (trifluoromethylsulfonyl) accounting for 10% of the mass of the polyethylene oxide, and uniformly mixing to obtain a mixed material;

and uniformly coating the mixed material on two opposite surfaces of the metal lithium sheet by adopting a brush coating method, controlling the thickness of the coating on each surface of the metal lithium sheet to be 20 mu m, and drying to obtain a composite film layer attached to the two surfaces of the metal lithium sheet, thereby obtaining the lithium-based electrode.

The obtained lithium-based electrode is used as a negative electrode and is assembled with a positive electrode of which the positive active material is lithium iron phosphate into a lithium iron phosphate battery, and the lithium iron phosphate battery is tested to be qualified through voltage and then is arranged on a battery tester according to the proportion of 5.5mA/cm²The current density of the lithium iron phosphate battery is subjected to cyclic charge and discharge tests, after the current density is cycled for 2000 times, the lithium iron phosphate battery is disassembled, and the surface of a negative electrode is subjected to charge and discharge testsNo significant lithium dendrites were observed and the utilization of the lithium-based electrode reached 89%.

Example 3

The present embodiment provides a lithium-based electrode, a method of manufacturing the same, and a secondary lithium battery, wherein the method of manufacturing the lithium-based electrode includes the steps of:

mixing polytetrafluoroethylene and hexagonal boron nitride according to the mass ratio of 4:6, adding a proper amount of N-polyvinylpyrrolidone, and uniformly mixing to obtain a mixed material;

and uniformly dip-coating the mixed material on two opposite surfaces of a lithium metal sheet by adopting a dip-coating method, controlling the thickness of the coating on each surface of the lithium metal sheet to be 50 mu m, and drying to obtain a composite film layer attached to the two surfaces of the lithium metal sheet, thereby obtaining the lithium-based electrode.

The obtained lithium-based electrode is used as a negative electrode and is assembled with a positive electrode of which the active material of the positive electrode is elemental sulfur into a lithium-sulfur battery, and the lithium-sulfur battery is tested to be qualified through voltage test and then is arranged on a battery tester according to the proportion of 1.8mA/cm²The current density of the lithium-sulfur battery is tested by cyclic charge and discharge, after the lithium-sulfur battery is cycled for 1000 times, no obvious lithium dendrite is observed on the surface of the negative electrode, and the utilization rate of the lithium-based electrode reaches 93 percent.

Example 4

The present embodiment provides a lithium-based electrode, a method of manufacturing the same, and a secondary lithium battery, wherein the method of manufacturing the lithium-based electrode includes the steps of:

mixing polytetrafluoroethylene with MoS₂Mixing materials according to the mass ratio of 1:4, simultaneously adding a proper amount of acetone and lithium hexafluoroarsenate accounting for 20% of the mass of the polytetrafluoroethylene, and uniformly mixing to obtain a mixed material;

and uniformly coating the mixed material on two opposite surfaces of the metal lithium sheet by adopting a flow coating method, controlling the thickness of the coating on each surface of the metal lithium sheet to be 2.0 mu m, and drying to obtain composite film layers attached to the two surfaces of the metal lithium sheet, thereby obtaining the lithium-based electrode.

The obtained lithium-based electrode is used as a negative electrode and is assembled with a positive electrode of which the positive active material is lithium iron phosphate to form a lithium iron phosphate battery, and the lithium iron phosphate battery is qualified after voltage inspectionOn a battery tester according to 3.6mA/cm²The current density is tested by cyclic charge and discharge, after the test is cycled for 2000 times, the lithium iron phosphate battery is disassembled, no obvious lithium dendrite is observed on the surface of the negative electrode, and the utilization rate of the lithium-based electrode reaches 99%.

Example 5

The present embodiment provides a lithium-based electrode, a method of manufacturing the same, and a secondary lithium battery, wherein the method of manufacturing the lithium-based electrode includes the steps of:

mixing polyacrylonitrile with ZnPS₃Mixing materials according to the mass ratio of 1:9, simultaneously adding a proper amount of acetone and lithium perchlorate accounting for 30% of the mass of the polyacrylonitrile, and uniformly mixing to obtain a mixed material;

and uniformly coating the mixed material on two opposite surfaces of the metal lithium sheet by adopting a spraying method, controlling the thickness of the coating on each surface of the metal lithium sheet to be 10 mu m, and drying to obtain a composite film layer attached to the two surfaces of the metal lithium sheet, thereby obtaining the lithium-based electrode.

Assembling the obtained lithium-based electrode as a negative electrode into a lithium-air battery, and testing the lithium-air battery to be qualified through voltage test according to the specification of 2.4mA/cm on a battery tester²The current density of the lithium-based electrode is tested by cyclic charge and discharge, after the lithium-air battery is cycled for 5000 times, the lithium-air battery is disassembled, no obvious lithium dendrite is observed on the surface of the negative electrode, and the utilization rate of the lithium-based electrode reaches 99.9 percent.

Example 6

The present embodiment provides a lithium-based electrode, a method of manufacturing the same, and a secondary lithium battery, wherein the method of manufacturing the lithium-based electrode includes the steps of:

mixing polyvinylidene fluoride and VOCl according to the mass ratio of 1:19, adding lithium bis (oxalato) borate accounting for 40% of the mass of the polyvinylidene fluoride, and uniformly mixing to obtain a mixed material;

and uniformly coating the mixed material on two opposite surfaces of the metal lithium sheet by adopting a thermal spraying method, controlling the thickness of the coating on each surface of the metal lithium sheet to be 15 mu m, and drying to obtain composite film layers attached to the two surfaces of the metal lithium sheet, thereby obtaining the lithium-based electrode.

The obtained lithium-based electrodeThe lithium cobalt oxide battery is used as a negative electrode and assembled with a positive electrode of which the positive electrode active material is lithium cobalt oxide into a lithium cobalt oxide battery, and the lithium cobalt oxide battery is tested to be qualified through voltage test and then is arranged on a battery tester according to the specification of 3.8mA/cm²The current density is tested by cyclic charge and discharge, after 1600 cycles, the lithium iron phosphate battery is disassembled, no obvious lithium dendrite is observed on the surface of the negative electrode, and the utilization rate of the lithium-based electrode reaches 86%.

Example 7

The present embodiment provides a lithium-based electrode, a method of manufacturing the same, and a secondary lithium battery, wherein the method of manufacturing the lithium-based electrode includes the steps of:

polyvinylidene fluoride-hexafluoropropylene copolymer, polyacrylonitrile and PbCl₄According to the mass ratio of 1: mixing materials according to the proportion of 1:98, simultaneously adding a proper amount of acetone and lithium bis (fluorosulfonyl imide) accounting for 50% of the total mass of the polyvinylidene fluoride-hexafluoropropylene copolymer and the polyacrylonitrile, and uniformly mixing to obtain a mixed material;

and uniformly coating the mixed material on two opposite surfaces of the metal lithium sheet by adopting a brush coating method, controlling the thickness of the coating on each surface of the metal lithium sheet to be 20 mu m, and drying to obtain a composite film layer attached to the two surfaces of the metal lithium sheet, thereby obtaining the lithium-based electrode.

The obtained lithium-based electrode was used as a negative electrode, and Li was used as a positive electrode active material_1.2Ni_0.13Mn_0.54Co_0.13O₂The positive pole of the material is assembled into a lithium-rich ternary lithium battery, and the lithium-rich ternary lithium battery is tested to be qualified through voltage test and then is tested on a battery tester according to the specification of 3.2mA/cm²The current density is tested by cyclic charge and discharge, after the lithium-rich ternary lithium battery is disassembled after the current density is cycled for 2500 times, no obvious lithium dendrite is observed on the surface of the negative electrode, and the utilization rate of the lithium-based electrode reaches 99.9 percent.

Example 8

The present embodiment provides a lithium-based electrode, a method of manufacturing the same, and a secondary lithium battery, wherein the method of manufacturing the lithium-based electrode includes the steps of:

mixing polyethylene oxide and MgO nanosheets according to the mass ratio of 1:999, simultaneously adding a proper amount of acetone and lithium bis (trifluoromethylsulfonyl) imide accounting for 10% of the mass of the polyethylene oxide, and uniformly mixing to obtain a mixed material;

and uniformly coating the mixed material on two opposite surfaces of the metal lithium sheet by adopting a brush coating method, controlling the thickness of the coating on each surface of the metal lithium sheet to be 20 mu m, and drying to obtain a composite film layer attached to the two surfaces of the metal lithium sheet, thereby obtaining the lithium-based electrode.

Assembling the obtained lithium-based electrode as a negative electrode into a lithium-air battery, and testing the lithium-air battery to be qualified through voltage test according to the specification of 5.0mA/cm on a battery tester²The current density of the lithium-based electrode is tested by cyclic charge and discharge, after the lithium-air battery is cycled for 800 times, lithium dendrite is not observed on the surface of the negative electrode, and the utilization rate of the lithium-based electrode reaches 99.99%.

Example 9

The present embodiment provides a lithium-based electrode, a method of manufacturing the same, and a secondary lithium battery, wherein the method of manufacturing the lithium-based electrode includes the steps of:

mixing polyvinyl chloride with Ni (OH)₂Mixing the nanosheets according to the mass ratio of 1:3, adding a proper amount of acetone and lithium perchlorate accounting for 15% of the mass of the polyvinyl chloride, and uniformly mixing to obtain a mixed material;

and uniformly coating the mixed material on two opposite surfaces of the metal lithium sheet by adopting a flow coating method, controlling the thickness of the coating on each surface of the metal lithium sheet to be 8.0 mu m, and drying to obtain composite film layers attached to the two surfaces of the metal lithium sheet, thereby obtaining the lithium-based electrode.

The obtained lithium-based electrode is used as a negative electrode and assembled with an air positive electrode to form a lithium air battery, and the lithium air battery is tested to be qualified through voltage and then is tested on a battery tester according to the specification of 1.5mA/cm²The current density of the lithium-based electrode is tested by cyclic charge and discharge, after 6000 cycles, the lithium-air battery is disassembled, no lithium dendrite is observed on the surface of the negative electrode, and the utilization rate of the lithium-based electrode reaches 98 percent.

Example 10

The present embodiment provides a lithium-based electrode, a method of manufacturing the same, and a secondary lithium battery, wherein the method of manufacturing the lithium-based electrode includes the steps of:

mixing polymethyl methacrylate with [ (Al)₂)(Si₂Al₂)O₁₀(OH)₂]Mixing the Ca according to the mass ratio of 7:13, simultaneously adding lithium bis (oxalato) borate accounting for 8% of the mass of the polymethyl methacrylate and lithium hexafluorophosphate accounting for 8% of the mass of the polymethyl methacrylate, and uniformly mixing to obtain a mixed material;

and uniformly coating the mixed material on two opposite surfaces of the metal lithium sheet by adopting a thermal spraying method, controlling the thickness of the coating on each surface of the metal lithium sheet to be 3 mu m, and drying to obtain composite film layers attached to the two surfaces of the metal lithium sheet, thereby obtaining the lithium-based electrode.

The obtained lithium-based electrode was used as a negative electrode, and Li was used as a positive electrode active material_1.2Mn_0.54Ni_0.13Co_0.13O₂The positive electrode is assembled into a lithium-rich ternary lithium battery, and the lithium-rich ternary lithium battery is tested to be qualified through voltage test and then is arranged on a battery tester according to the proportion of 4.0mA/cm²The current density is tested by cyclic charge and discharge, after the current density is cycled for 4000 times, the lithium-rich ternary lithium battery is disassembled, no lithium dendrite is observed on the surface of the negative electrode, and the utilization rate of the lithium-based electrode reaches 96%.

Example 11

The present embodiment provides a lithium-based electrode, a method of manufacturing the same, and a secondary lithium battery, wherein the method of manufacturing the lithium-based electrode includes the steps of:

mixing sodium carboxymethylcellulose with C₃N₄Mixing the nanosheets and the GaSe nanosheets according to the mass ratio of 1:4:5, simultaneously adding a proper amount of N-methyl pyrrolidone and lithium hexafluoroborate accounting for 45% of the mass of the sodium carboxymethylcellulose, and uniformly mixing to obtain a mixed material;

and uniformly coating the mixed material on two opposite surfaces of the metal lithium sheet by adopting a brush coating method, controlling the thickness of the coating on each surface of the metal lithium sheet to be 13 mu m, and drying to obtain a composite film layer attached to the two surfaces of the metal lithium sheet, thereby obtaining the lithium-based electrode.

Assembling the obtained lithium-based electrode as a negative electrode into a lithium-air battery, and testing the lithium-air battery to be qualified through voltage test according to the specification of 3.0mA/cm on a battery tester²The current density of the battery is subjected to cyclic charge-discharge test, and after 4000 cycles, the battery is disassembledIn the lithium air battery, lithium dendrite is not observed on the surface of the negative electrode, and the utilization rate of the lithium-based electrode reaches 98%.

Example 12

The present embodiment provides a lithium-based electrode, a method of manufacturing the same, and a secondary lithium battery, wherein the method of manufacturing the lithium-based electrode includes the steps of:

mixing polyvinyl formal and montmorillonite nanosheets according to the mass ratio of 11:39, adding a proper amount of acetone and lithium bis (trifluoromethylsulfonyl) imide accounting for 3% of the mass of the polyvinyl formal, and uniformly mixing to obtain a mixed material;

and uniformly coating the mixed material on two opposite surfaces of the metal lithium sheet by adopting a dip-coating method, controlling the thickness of the coating on each surface of the metal lithium sheet to be 2.0 mu m, and drying to obtain composite film layers attached to the two surfaces of the metal lithium sheet, thereby obtaining the lithium-based electrode.

The obtained lithium-based electrode is used as a negative electrode and is assembled with a positive electrode of which the active material of the positive electrode is elemental sulfur into a lithium-sulfur battery, and the lithium-sulfur battery is tested to be qualified through voltage test and then is arranged on a battery tester according to the proportion of 3.5mA/cm²The current density of the lithium-sulfur battery is tested by cyclic charge and discharge, after the lithium-sulfur battery is cycled for 1000 times, lithium dendrite is not observed on the surface of a negative electrode, and the utilization rate of the lithium-based electrode reaches 99%.

Example 13

The present embodiment provides a lithium-based electrode, a method of manufacturing the same, and a secondary lithium battery, wherein the method of manufacturing the lithium-based electrode includes the steps of:

mixing polyurethane and hydrotalcite nanosheets according to the mass ratio of 2:3, adding a proper amount of acetone and lithium difluorooxalato borate accounting for 12% of the mass of the polyurethane, and uniformly mixing to obtain a mixed material;

and uniformly coating the mixed material on two opposite surfaces of the metal lithium sheet by adopting a spraying method, controlling the thickness of the coating on each surface of the metal lithium sheet to be 100nm, and drying to obtain a composite film layer attached to the two surfaces of the metal lithium sheet, thereby obtaining the lithium-based electrode.

The obtained lithium-based electrode is used as a negative electrode to assemble a lithium air batteryAfter passing the voltage test, the voltage is tested to be qualified and is measured on a battery tester according to the specification of 1.5mA/cm²The current density of the lithium-based electrode is tested by cyclic charge and discharge, after 6000 cycles, the lithium-air battery is disassembled, no lithium dendrite is observed on the surface of the negative electrode, and the utilization rate of the lithium-based electrode reaches 98 percent.

Example 14

The present embodiment provides a lithium-based electrode, a method of manufacturing the same, and a secondary lithium battery, wherein the method of manufacturing the lithium-based electrode includes the steps of:

mixing polyvinyl butyral and graphite nanosheets according to the mass ratio of 23:77, adding a proper amount of acetone and lithium bis (oxalato) borate accounting for 2% of the mass of the polyvinyl butyral, and uniformly mixing to obtain a mixed material;

and uniformly coating the mixed material on two opposite surfaces of the metal lithium sheet by adopting a flow coating method, controlling the thickness of the coating on each surface of the metal lithium sheet to be 500nm, and drying to obtain composite film layers attached to the two surfaces of the metal lithium sheet, thereby obtaining the lithium-based electrode.

The obtained lithium-based electrode is used as a negative electrode and is assembled with a positive electrode which is a positive electrode active material and is elemental sulfur to form a lithium iron phosphate battery, and the lithium iron phosphate battery is tested to be qualified through voltage and then is arranged on a battery tester according to the specification of 2.5mA/cm²The current density of the lithium-sulfur battery is tested by cyclic charge and discharge, and after the lithium-sulfur battery is cycled for 1600 times, lithium dendrites are not observed on the surface of the negative electrode, and the utilization rate of the lithium-based electrode reaches 86%.

Example 15

The present embodiment provides a lithium-based electrode, a method of manufacturing the same, and a secondary lithium battery, wherein the method of manufacturing the lithium-based electrode includes the steps of:

mixing perfluorosulfonic acid resin with TaS₃Mixing the nanosheets according to the mass ratio of 3:97, adding a proper amount of acetone, and uniformly mixing to obtain a mixed material;

and uniformly coating the mixed material on two opposite surfaces of the metal lithium sheet by adopting a brush coating method, controlling the thickness of the coating on each surface of the metal lithium sheet to be 20 mu m, and drying to obtain a composite film layer attached to the two surfaces of the metal lithium sheet, thereby obtaining the lithium-based electrode.

The obtained lithium-based electrode is used as a negative electrode and assembled into a lithium air battery, and the lithium air battery is tested to be qualified through voltage test and then is tested on a battery tester according to the specification of 2.0mA/cm²The current density of the lithium-based electrode is tested by cyclic charge and discharge, after the lithium-air battery is cycled for 800 times, lithium dendrite is not observed on the surface of the negative electrode, and the utilization rate of the lithium-based electrode reaches 98%.

It can be known from the above embodiments 1 to 15 that, in the lithium-based electrode provided in the embodiments of the present invention, since the composite film layer is attached to the surface of the lithium substrate, the lithium substrate is almost completely isolated from the outside, and the composite film layer includes the organic polymer material and the two-dimensional inorganic sheet material, the composite film layer has a certain mechanical strength, when the lithium-based electrode is used as a negative electrode to assemble a secondary lithium battery, the contact area between the lithium substrate and an electrolyte can be effectively reduced, side reactions between the lithium substrate and the electrolyte can be reduced, and the growth of lithium dendrites can be effectively inhibited, so that the safety performance, the electrode utilization rate, and the coulombic efficiency of the secondary lithium battery can be improved, and the cycle performance of the secondary lithium battery can also be improved.

While the foregoing is directed to embodiments of the present invention, it will be understood by those skilled in the art that various changes may be made without departing from the spirit and scope of the invention.