Negative electrode, preparation thereof, and battery

Abstract

The application discloses a negative electrode and a preparation method and a battery thereof. The negative electrode comprises a negative electrode body and a alkali metalizable layer which is laminated on the outer surface of the negative electrode material layer of the negative electrode body. The alkali metalizable layer is non-conductive and has good alkali metal ion conductivity. In the charge and discharge cycle, the alkali metal deposition of the negative electrode can only occur in the negative electrode material layer or at the interface between the negative electrode material layer and the alkali metalizable layer, thereby reducing the contact with the electrolyte and dendrite formation, improving the stability of the safety performance and electrochemical performance of the battery containing the negative electrode. The preparation method can ensure the stability of the performance and quality of the prepared negative electrode. The battery containing the negative electrode has stable electrochemical performance, high safety and long service life in the charge and discharge cycle.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of batteries, and particularly relates to a negative electrode, preparation thereof and a battery. BACKGROUND

[0002] With the enhancement of people's awareness of environmental protection and energy crisis, batteries as a green and environmentally friendly energy storage technology are more and more popular. For example, lithium batteries are widely used due to their high energy density, long cycle life and high stability. With the wide application of electronic products and the vigorous development of electric vehicles, the market of lithium ion batteries is increasingly broad, but at the same time, higher requirements are put forward for the safety of lithium ion batteries.

[0003] At present, commercial lithium ion batteries mainly use carbon-based materials such as graphite as negative electrodes, and the limited theoretical capacity (372 mAh / g) has been almost fully developed. High energy density helps to improve the mass energy density or volume energy density of the overall battery. Under such demand, it is urgent to develop new negative electrode materials with high energy density. Among them, metal lithium has the lowest electrochemical potential (-3.04 V vs. SHE), lower density (0.534 g cm -3 ) and higher specific energy density (theoretical capacity 3860 mAh / g), and the 0 V lithium potential can also maximize the use of the voltage of the positive electrode material, so that the battery can output higher working voltage and energy density. The theoretical energy density of lithium-air battery and lithium-sulfur battery with lithium metal negative electrode can be as high as 3500 and 2600 Wh Kg -1 The realization of stable cycle lithium metal negative electrode has been considered as the holy grail of lithium battery. It is also the key to realize the next generation of high energy density rechargeable batteries.

[0004] However, lithium batteries, including lithium ion battery negative electrode and metal lithium negative electrode, will face problems such as lithium dendrite growth, lithium deactivation, and inevitable volume expansion caused by lithium deposition and stripping during actual battery operation. These problems will either cause serious safety problems or sharply deteriorate the electrochemical performance. In order to improve the above problems, researchers have made a lot of research on the introduction of functional layers on the surface, such as Figure 1 The structure shown in a figure of the currently disclosed is a conductive modification layer 02 formed by a conductive electron and ion graphite and its lithiated compound covering the negative electrode body 01 (lithium metal electrode). Another metal lithium electrode is also disclosed, which is provided with a conductive modification layer (specifically a conductive nucleation layer) between the negative electrode current collector and the negative electrode material layer (metal lithium layer); or as Figure 1The metal lithium electrode shown in FIG. a has an electrically conductive modification layer 02 (specifically, an electrically conductive nucleation layer, which is arranged between the metal lithium layer and the current collector layer 011 in the metal lithium electrode structure) added to the outer surface of the negative electrode material layer 012 (metal lithium layer) contained in the negative electrode body 01, and the nucleation layer contains electrically conductive nanosheets. When the metal lithium electrode has the electrically conductive nucleation layer added, the electrically conductive nanosheets play the role of a nucleating agent for the metal lithium during charging and discharging, and in the process of lithium deposition, the lithium is deposited on the electrically conductive nanosheets in the electrically conductive modification layer 02, as shown in FIG. b, so that the deposition of the metal lithium 03 on the electrically conductive nanosheets in the electrically conductive modification layer 02 is controllable nucleation and growth, so as to control the formation of sharp lithium dendrites 031. Some research teams have also introduced nanosilicon into a graphene layer to prepare a silicon / graphene lithium metal surface modification layer. Figure 1

[0005] Although the electrodes described above contain the electrically conductive modification layer 02 (surface layer lithium compound or electrically conductive nucleation layer) that can be lithiumophilic to a certain extent, reduces the lithium metal 03 surface deposition current, and to a certain extent, reduces the generation of dendrites 031. However, due to the electrically conductive characteristics of the electrically conductive modification layer 02 itself or its lithiumated product, a part of the lithium ions will inevitably be deposited on the electrically conductive modification layer 02 and its surface, and there is still a risk of lithium dendrites 031 existing and growing, and the electrically conductive modification layer 02 is directly attached to the separator, as shown in FIG. b. Especially in the case of large current, the surface dendrite morphology is more prominent. As in the disclosed metal lithium electrode containing the electrically conductive nucleation layer, although the electrically conductive nucleation layer can inhibit the nucleation and growth of the deposited metal lithium to a certain extent, but due to the electrically conductive performance of the electrically conductive nucleation layer, and the metal lithium layer is also electrically conductive, therefore, no matter whether the electrically conductive nucleation layer is distributed between the metal lithium layer and the current collector or directly distributed on the outer surface of the metal lithium layer, with the battery cycle discharging, the deposition of lithium metal will occur on the surface of the metal lithium layer or the surface of the electrically conductive nucleation layer and nucleate and grow, with the cycle discharging, the deposited metal lithium is easy to form lithium dendrites, and continuously exposed to the electrolyte consumes the electrolyte, which still leads to the battery safety problem and rapid performance degradation. Figure 1 Figure 1 Therefore, it is very important to design a surface modification lithium metal negative electrode with a simple process, which can ensure that the lithium metal is deposited on the lower layer regardless of the size of the current.

[0006] Therefore, it is very important to design a surface modification lithium metal negative electrode with a simple process, which can ensure that the lithium metal is deposited on the lower layer regardless of the size of the current. SUMMARY

[0007] The purpose of the present application is to overcome the above-mentioned shortcomings of the prior art, and to provide a negative electrode and a preparation method thereof, so as to solve the technical problem that the existing negative electrode such as the metal lithium electrode has an unsatisfactory effect on inhibiting the growth of lithium dendrites.

[0008] Another purpose of the present application is to provide a battery to solve the technical problem that the existing battery contains a negative electrode with an unsatisfactory effect on inhibiting the growth of dendrites, resulting in unsatisfactory battery safety. ​​

[0009] To achieve the above object, one aspect of the present application provides a negative electrode. The negative electrode of the present application comprises a negative electrode body provided with a negative electrode material layer, and further comprises an alkali-metalizable layer laminated on the outer surface of the negative electrode material layer, the alkali-metalizable layer having an electronic conductivity lower than that of the negative electrode material layer and having alkali metal ion conductivity.

[0010] Another aspect of the present application provides a method for preparing the negative electrode of the present application. The method for preparing the negative electrode of the present application comprises the following steps:

[0011] providing a negative electrode body;

[0012] forming an alkali-metalizable layer on the outer surface of the negative electrode material layer of the negative electrode body, the alkali-metalizable layer having an electronic conductivity lower than that of the negative electrode material layer and having alkali metal ion conductivity.

[0013] Still another aspect of the present application provides a battery. The battery of the present application comprises a positive electrode, a negative electrode and a separator laminated between the positive electrode and the negative electrode, the negative electrode being the negative electrode of the present application or the negative electrode prepared by the method for preparing the negative electrode of the present application.

[0014] Compared with the prior art, the present application has the following technical effects:

[0015] The alkali-metalizable layer contained in the negative electrode of the present application is arranged on the outer surface of the negative electrode material layer contained in the negative electrode body, and has alkali-metalizability, so that the alkali-metalizable layer plays a role in guiding and uniformly distributing alkali metal ions, effectively reducing the deposition of alkali metal and the formation of dendrites in the charge and discharge cycle. Since the electronic conductivity of the alkali-metalizable layer is lower than that of the negative electrode material layer and the alkali-metalizable layer has alkali metal ion conductivity, alkali metal ions are reduced to metal by electrons during the deposition of alkali metal, so that the deposition of alkali metal can only occur in the negative electrode material layer having relatively excellent electrical conductivity or at the interface between the negative electrode material layer and the alkali-metalizable layer, effectively preventing the deposition of alkali metal from directly occurring on the outer surface of the alkali-metalizable layer. At this time, the alkali-metalizable layer plays a role of a protective layer and a buffer layer, avoiding the dendrites generated by the deposition of alkali metal from directly piercing the separator to cause short circuit, thereby improving the safety performance of the battery containing the negative electrode of the present application, and avoiding the direct contact of the negative electrode body with the electrolyte, improving the stability of the electrochemical performance of the negative electrode and the electrolyte in the charge and discharge cycle. In addition, the alkali-metalizable layer having alkali-metalizability can also effectively improve the migration of alkali metal ions and improve the electrochemical performance of the negative electrode.

[0016] The negative electrode preparation method directly forms the alkali metalizable layer on the outer surface of the negative electrode material layer of the negative electrode body, so that the prepared negative electrode has the above-mentioned electrochemical performance of the negative electrode of the application, and the process conditions of the preparation method are easy to control, which can ensure the stability of the performance and quality of the prepared negative electrode and high efficiency.

[0017] The battery contains the negative electrode of the application, so the battery has stable electrochemical performance, high safety and long service life during the charge and discharge cycle. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the specific embodiments of the application or the technical solutions in the prior art, the drawings needed in the specific embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0019] Figure 1 It is a structure schematic diagram of the existing metal lithium electrode structure and its charge and discharge cycle to form deposited lithium metal; wherein, a diagram is a structure schematic diagram of the existing metal lithium electrode structure without deposited lithium metal; b diagram is a structure schematic diagram of the existing metal lithium electrode with deposited lithium metal and formed lithium dendrites in the charge and discharge cycle;

[0020] Figure 2 It is a structure schematic diagram of the negative electrode structure of the embodiment of the application and its charge and discharge cycle to form deposited alkali metal; wherein, c diagram is a structure schematic diagram of the negative electrode structure of the embodiment of the application without deposited alkali metal; d diagram is a structure schematic diagram of the negative electrode of the embodiment of the application with deposited alkali metal in the charge and discharge cycle;

[0021] Figure 3 It is a structure schematic diagram of the negative electrode structure of the embodiment of the application with single-side containing alkali metalizable layer;

[0022] Figure 4 It is a structure schematic diagram of the negative electrode structure of the embodiment of the application with double-side containing alkali metalizable layer;

[0023] Figure 5 It is a lithium metal battery cycle performance curve provided by example B1 and comparative example B3;

[0024] Figure 6 It is a lithium metal battery cycle performance curve provided by example B2 and comparative example B2;

[0025] Figure 7 It is a lithium metal battery cycle performance curve provided by example B3 and comparative example B4;

[0026] Figure 8A lithium metal battery cycle performance graph provided for Example B4 and Comparative Example B1.

[0027] Explanation of component numbers in each figure:

[0028] 01 - negative electrode body of existing lithium battery, 011 - current collector contained in negative electrode body 01 of existing lithium battery, 012 - negative electrode material layer contained in negative electrode body 01 of existing lithium battery;

[0029] 02 - conductive modification layer contained in existing lithium battery;

[0030] 03 - deposited metal lithium layer in cycle of existing lithium battery, 031 - lithium dendrite grown in cycle of existing lithium battery;

[0031] 1 - negative electrode body contained in negative electrode of the present application, 11 - current collector contained in negative electrode body 1 of the present application, 12 - negative electrode material layer contained in negative electrode body 1 of the present application;

[0032] 2 - alkali metalizable layer contained in negative electrode of the present application;

[0033] 3 - deposited metal lithium layer in cycle of lithium battery containing negative electrode of the present application. DETAILED DESCRIPTION

[0034] In order to make the objectives, technical solutions and technical effects of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application are described clearly and completely, and the following described embodiments are part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those skilled in the art without creative labor on the basis of the embodiments in the present application all belong to the scope of protection of the present application. The specific conditions not mentioned in the embodiments are carried out according to the conventional conditions or the conditions suggested by the manufacturer; the reagents or instruments not mentioned by the manufacturer are all conventional products that can be obtained by market purchase.

[0035] In the description of the present application, the term "and / or" describes the association relationship of the associated objects, which means that there can be three kinds of relationships, for example, A and / or B can mean that A exists alone, A and B exist together, and B exists alone. Wherein A and B can be singular or plural. The character " / " generally represents that the associated objects before and after it are in an "or" relationship.

[0036] In the description of the present application, "at least one" means one or more, and "a plurality of" means two or more. "At least one of the following" or similar expressions means any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can mean a, b, c, a-b (i.e. a and b), a-c, b-c, or a-b-c, where a, b, and c can be single or multiple.

[0037] It should be understood that the weight of the related components mentioned in the embodiments of the present application can not only refer to the specific content of each component, but also represent the proportional relationship between the weights of each component. Therefore, as long as the content of the related components in the embodiments of the present application is enlarged or reduced in proportion, it is within the scope disclosed by the present application. Specifically, the weight mentioned in the embodiments of the present application can be μg, mg, g, kg, etc. mass units commonly known in the chemical industry.

[0038] In addition, unless the context clearly indicates otherwise, the expression of the singular form of a word should be understood to include the plural form of the word. The term "includes" or "has" is intended to specify the presence of a feature, quantity, step, operation, element, part, or combination thereof, but is not used to exclude the presence or possible addition of one or more other features, quantities, steps, operations, elements, parts, or combinations thereof.

[0039] Explanation of the following related names:

[0040] Alkali metalizable material: In the embodiments of the present application, it refers to a material with alkali storage property.

[0041] Lithiumizable material: refers to a material with lithium storage property.

[0042] Sodiumizable material: refers to a material with sodium storage property.

[0043] Magnesiumizable material: refers to a material with magnesium storage property.

[0044] Alkali metalizable layer: refers to a layer structure containing the above-mentioned alkali metalizable material, which has lower electronic conductivity than the negative electrode material layer and has alkali metal ion conductivity.

[0045] Alkali metal ion / alkali metal hybrid battery: refers to the hybrid battery belonging to the upper level of the lithium ion battery and lithium metal battery hybrid battery type proposed by Alex Louli of University of Waterloo and Jeff Dahn of Dalhousie University. When the alkali metal is lithium, it is the lithium ion battery and lithium metal battery hybrid battery proposed by Alex Louli and Jeff Dahn; when the alkali metal is sodium, it is the sodium ion battery and sodium metal battery hybrid battery; when the alkali metal is magnesium, it is the magnesium ion battery and magnesium metal battery hybrid battery. In these alkali metal ion / alkali metal hybrid batteries, the positive electrode capacity is greater than the negative electrode capacity (N / P<1). Therefore, after continuous charging, alkali metal ions such as lithium ions will be deposited in the form of alkali metals such as metal lithium on the negative electrode to form a metal alkali layer such as a metal lithium layer.

[0046] In one aspect, the embodiment of the present application provides a negative electrode. The structure of the negative electrode is shown in Figures 2 to 4 , which includes a negative electrode body 1 and an alkali metalizable layer 2.

[0047] Among them, the negative electrode contains an alkali metalizable layer 2 laminated on the outer surface of the negative electrode material layer 12 of the negative electrode body 1, specifically Figure 2 , and Figure 3 , and Figure 4 As shown, and the electronic conductivity of the alkali metalizable layer 2 is lower than that of the negative electrode material layer 12, and the alkali metalizable layer 2 has alkali metal ion conductivity.

[0048] In this way, the alkali metalizable layer 2 contained in the negative electrode is arranged on the outer surface of the negative electrode material layer 12 contained in the negative electrode body 1, and the alkali metalizable layer 2 plays a role in guiding and uniformizing alkali metal ions, effectively reducing alkali metal deposition and reducing dendrite formation in the charge and discharge cycle.

[0049] In addition, because the alkali metalizable layer 2 has the characteristics of low electronic conductivity relative to the negative electrode material layer 12 and good alkali metal ion conductivity, the alkali metal ions are reduced to metal in the process of alkali metal deposition in the charge and discharge cycle of the negative electrode of the embodiment of the present application. In this context, alkali metal deposition can only or preferentially occur in the negative electrode material layer 12 or at the interface between the negative electrode material layer 12 and the alkali metalizable layer 2, as shown in Figure 2The deposition of alkali metal 3 shown in FIG. 2D occurs at the interface between the negative electrode material layer 12 and the alkali metalizable layer 2, and also occurs in the negative electrode material layer 12, thereby effectively preventing the direct deposition of alkali metal 3 on the outer surface of the alkali metalizable layer 2. At this time, the alkali metalizable layer 2 functions as a separator protection layer and a dendrite buffer layer, avoiding the direct puncture of the separator by the dendrites generated by the deposition of alkali metal, thereby improving the safety performance of the battery containing the negative electrode of the embodiment of the present application, and reducing the direct contact of the deposited alkali metal with the electrolyte in the electrochemical cycle, thereby improving the stability of the electrochemical performance of the negative electrode and the electrolyte in the charge and discharge cycle. In addition, the alkali metalizable layer 2 has the alkali metalizable property, and can also effectively improve the migration of alkali metal ions, thereby improving the electrochemical performance of the negative electrode. Therefore, the negative electrode of the embodiment of the present application effectively overcomes the problem of the existing negative electrode shown in FIG. 1D, in which the deposition of lithium metal 03 in the charge and discharge cycle occurs in the conductive modification layer 02 and on the surface thereof, thereby resulting in the unsatisfactory safety performance of the negative electrode. Figure 1

[0050] In addition, the alkali metalizable layer 2 having the alkali metal ion conductivity in the embodiment of the present application refers to the good alkali metal ion conductivity: 1) the material contained in the alkali metalizable layer itself has a relatively high intrinsic or apparent alkali metal ion conductivity, and when the ions migrate through the alkali metalizable layer, the property of the alkali metalizable layer facilitates the rapid movement of lithium ions through the alkali metalizable layer to the negative electrode body, and the lithium ions are not enriched in the alkali metalizable layer, especially on the surface thereof, thereby avoiding the deposition of the alkali metal ions at least on the outer surface of the alkali metalizable layer.

[0051] According to the structure of the negative electrode of the embodiment of the present application, in the embodiment, when the negative electrode body 1 contains the negative electrode material layer 12 on one of the two opposite surfaces, the alkali metalizable layer 2 is only laminated on the outer surface of the negative electrode material layer 12, that is, the alkali metalizable layer 2 is only laminated on the surface of the negative electrode material layer 12 away from the current collector 11, as shown in FIG. 2A. Figure 2 At this time, when the negative electrode of the embodiment of the present application is attached to the separator, the alkali metalizable layer 2 is attached to the separator, so that the alkali metalizable layer 2 plays the role of the alkali metalizable layer 2 described above, thereby improving the safety performance and the electrochemical stability of the negative electrode of the embodiment.

[0052] In another embodiment, when the negative electrode body 1 contains the negative electrode material layer 12 on both of the two opposite surfaces, and the alkali metalizable layer 2 is only one layer and is only laminated on the outer surface of one of the negative electrode material layers 12, as shown in FIG. 2B. Figure 3 At this time, when the negative electrode of the embodiment of the present application is attached to the separator, the alkali metalizable layer 2 is attached to the separator, so that the alkali metalizable layer 2 plays the role of the alkali metalizable layer 2 described above, thereby improving the safety performance and the electrochemical stability of the negative electrode of the embodiment. ​

[0053] In another embodiment, when the negative electrode body 1 contains negative electrode material layers 12 on both opposite surfaces, and the alkali-compatible metallization layer 2 consists of two layers, with one alkali-compatible metallization layer 2 stacked on the outer surface of one negative electrode material layer 12 and the other alkali-compatible metallization layer 2 stacked on the outer surface of the other negative electrode material layer 12, as follows: Figure 4 As shown. At this time, when the negative electrode of this embodiment of the invention is bonded to the diaphragm, any one of the alkali-compatible metallization layers 2 is bonded to the diaphragm so that the alkali-compatible metallization layer 2 can perform the functions of the aforementioned alkali-compatible metallization layer 2, thereby improving the safety and electrochemical stability of the negative electrode of this embodiment.

[0054] Among them, such as Figures 2 to 4 The negative electrode shown can be selected according to the specific battery type. Regardless of the structure of the negative electrode, in this embodiment, the conductivity x of the alkali-metallized layer 2 and the conductivity y of the negative electrode material layer 12 are controlled to satisfy: y / x ≥ 10. 3 By controlling the difference in conductivity between the two, the role of the alkali metallization layer 2 as described above in the embodiments of the present invention is fully utilized, further promoting the deposition of alkali metal below the outer surface of the alkali metallization layer 2, and more preferentially depositing it in the negative electrode material layer 12 or at the interface between the negative electrode material layer 12 and the alkali metallization layer 2, thereby improving the protective effect of the alkali metallization layer 2.

[0055] In this embodiment, the alkali-metallized layer 2 comprises an alkali-metallized material and a binder, with the binder accounting for 0%-50% of the weight of the alkali-metallized material. When the binder content is 0%, the alkali-metallized layer 2 contains no binder and can consist solely of the alkali-metallized material. When the binder content is not 0%, the alkali-metallized layer 2 comprises a mixture of binder and alkali-metallized material. Specifically, this can be determined based on the formation method of the alkali-metallized layer 2 or the mechanical performance requirements of its bonding with the negative electrode material layer 12 of the negative electrode body 1. Regardless of whether the alkali-metallized layer 2 contains a binder, it should satisfy the above-mentioned requirement that the electronic conductivity of the alkali-metallized layer 2 is lower than that of the negative electrode material layer 12, and that the alkali-metallized layer 2 possesses alkali metal ion conductivity characteristics. Therefore, by controlling its components, the alkali-metallized layer 2 is endowed with relatively low conductivity or insulation and alkali metal ion affinity, thus giving the negative electrode of this embodiment of the invention excellent safety and electrochemical performance.

[0056] In this embodiment of the invention, the alkali-compatible metallization layer 2 contains any one of lithium-compatible materials, sodium-compatible materials, and magnesium-compatible materials. The specific selection and control can be flexibly made according to the type of battery to which the negative electrode is applied.

[0057] When the negative electrode of the embodiment of the present application is applied to a lithium battery, the alkali-metalizable material contained in the alkali-metalizable layer 2 is a lithiumizable material. In specific embodiments, the lithiumizable material includes at least one of lithium titanate, titanium dioxide, molybdenum disulfide, manganese dioxide, copper oxide, and iron oxide. The lithiumizable material not only has low electronic conductivity and good lithiumizability, has high lithium ion conductivity, such as high lithium storage, so that the deposited alkali metal 3 (specifically lithium metal) does not deposit and grow dendrites on the outer surface of the alkali-metalizable layer 2 in the cycle, that is, the deposited alkali metal 3 (specifically lithium metal) is deposited in the negative electrode material layer 12 or further at the interface between the negative electrode material layer 12 and the alkali-metalizable layer 2; but also has excellent lithiumizability, can provide lithium ion conductivity, reduce the polarization resistance of the alkali-metalizable layer 2, and improve the electrical performance of the lithium battery.

[0058] When the negative electrode of the embodiment of the present application is applied to a sodium battery, the alkali-metalizable material contained in the alkali-metalizable layer 2 is a sodiumizable material. In specific embodiments, the sodiumizable material includes at least one of titanium dioxide, molybdenum disulfide, manganese dioxide, copper oxide, and iron oxide. The sodiumizable material not only has low electronic conductivity and good sodiumizability, has high sodium ion conductivity, such as high sodium storage, so that the deposited alkali metal 3 (specifically sodium metal) does not deposit and grow dendrites on the outer surface of the alkali-metalizable layer 2 in the cycle, that is, the deposited alkali metal 3 (specifically sodium metal) is deposited in the negative electrode material layer 12 or further at the interface between the negative electrode material layer 12 and the alkali-metalizable layer 2; but also has excellent sodiumizability, can provide sodium ion conductivity, reduce the polarization resistance of the alkali-metalizable layer 2, and improve the electrical performance of the sodium battery.

[0059] When the negative electrode of the embodiment of the present application is applied to a magnesium battery, the alkali-metalizable material contained in the alkali-metalizable layer 2 is a magnesiumizable material. In specific embodiments, the magnesiumizable material includes at least one of magnesium titanate, titanium dioxide, molybdenum disulfide, manganese dioxide, copper oxide, and iron oxide. The magnesiumizable material not only has low electronic conductivity and good magnesiumizability, has high magnesium ion conductivity, such as high magnesium storage, so that the deposited alkali metal 3 (specifically magnesium metal) does not deposit and grow dendrites on the outer surface in the cycle, that is, the deposited alkali metal 3 (specifically magnesium metal) is deposited in the negative electrode material layer 12 or further at the interface between the negative electrode material layer 12 and the alkali-metalizable layer 2; but also has excellent magnesiumizability, can provide magnesium ion conductivity, reduce the polarization resistance of the alkali-metalizable layer 2, and improve the electrical performance of the magnesium battery.

[0060] In addition, regardless of the alkali-metalizable material contained in the alkali-metalizable layer 2, the alkali-metalizable material is in a granular morphology, and the particle size of the granules is in a sub-micron or / and nano-particle size range. The alkali-metalizable material with the particle size range is capable of packing to form abundant and uniform through tiny, such as nano-scale, channels to homogenize the distribution of alkali metal ions, such as lithium, sodium, magnesium ions, in the electrolyte, in particular, the ion concentration on the surface of the negative electrode body 1, so that the alkali metal ions are more evenly deposited, and the risk of dendrite formation is reduced. Even if dendrite phenomenon occurs, the alkali-metalizable material can be contacted to be lithiated, thereby also terminating the further growth of the dendrites.

[0061] When the alkali-metalizable layer 2 contains a binder, in the embodiments, the binder includes at least one of polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyacrylic acid, and hydroxymethyl cellulose acetate. The binder is insulating and does not affect the alkali-metalizable material to exert the above-mentioned properties and effects of being alkali metal ionophilic and alkali-metalizable, while being capable of improving the bonding strength between the alkali-metalizable layer 2 and the negative electrode material layer 12, and improving the stability of the structure and electrochemical performance of the negative electrode.

[0062] In the embodiments, the thickness of the alkali-metalizable layer 2 in each of the above-mentioned embodiments is 1 μm-50 μm. The alkali-metalizable layer 2 with the thickness range is capable of fully exerting the effects of the alkali-metalizable layer 2 described above, and improving the safety and stability of the electrochemical performance of the negative electrode.

[0063] Based on the alkali-metalizable layer 2 contained in the above-mentioned negative electrode, the negative electrode body 1 contained in the negative electrode can be a conventional battery negative electrode body, such as a negative electrode body of an alkali metal battery, a negative electrode body of an alkali metal ion battery, and a negative electrode body of an alkali metal ion / alkali metal hybrid battery.

[0064] Regardless of the negative electrode body 1 being a negative electrode body of any battery, the material of the negative electrode material layer 12 contained in the negative electrode body 1 should correspond to the material of the alkali-metalizable layer 2, in particular, when the material of the negative electrode material layer 12 is a negative electrode material of a lithium metal battery or a lithium ion battery or a lithium ion / lithium metal hybrid battery, then the material of the alkali-metalizable layer 2 should contain a lithiumizable material; when the material of the negative electrode material layer 12 is a negative electrode material of a sodium metal battery or a sodium ion battery or a sodium ion / sodium metal hybrid battery, then the material of the alkali-metalizable layer 2 should contain a sodiumizable material; when the material of the negative electrode material layer 12 is a negative electrode material of a magnesium metal battery or a magnesium ion battery or a magnesium ion / magnesium metal hybrid battery, then the material of the alkali-metalizable layer 2 should contain a magnesiumizable material.

[0065] When the negative electrode body 1 is a negative electrode body of an alkali metal battery, it can be, for example, Figures 2 to 4The shown negative electrode body 1, comprising a current collector 11 and at least a corresponding negative electrode material layer 12 combined on one surface of the current collector 11, then the alkali-metalizable layer 2 is directly laminated and combined on the surface of the negative electrode material layer 12. Moreover, the material of the negative electrode material layer 12 is a corresponding alkali metal (element or alloy).

[0066] In specific embodiments, the negative electrode material layer 12 has a morphology of at least one of an alkali metal (element or alloy) foil, mesh, and felt, wherein the alkali metal refers to an elemental alkali metal or an alloy containing an alkali metal. Specifically, when the alkali metal battery is a lithium metal battery, the alkali metal contained in the negative electrode material layer 12 is lithium metal (element or alloy), wherein when the lithium metal is an alloy, it can be but is not limited to one of a lithium-magnesium alloy foil, a lithium-aluminum alloy foil, and a lithium-boron alloy. When the alkali metal battery is a sodium metal battery, the alkali metal contained in the negative electrode material layer 12 is sodium metal (element or alloy). When the alkali metal battery is a magnesium metal battery, the alkali metal contained in the negative electrode material layer 12 is magnesium metal (element or alloy).

[0067] When the negative electrode body 1 is a negative electrode body of an alkali metal battery, the thickness of the negative electrode material layer 12 can be a conventional or improved thickness of the alkali metal negative electrode sheet contained in the alkali metal battery. In embodiments, in combination with the negative electrode in the above embodiments, the negative electrode material layer 12 is, for example, 30-100 μm.

[0068] Of course, when the negative electrode body 1 is a negative electrode body of an alkali metal battery, it can not contain the current collector 11, that is, the negative electrode body 1 is directly an alkali metal substrate (does not contain the current collector), at this time, the alkali-metalizable layer 2 is directly laminated and combined on one surface or two oppositely arranged surfaces of the alkali metal substrate. Moreover, the alkali metal substrate is at least one of an alkali metal (element or alloy) foil, mesh, and felt, and the alkali metal of the alkali metal substrate can be an elemental alkali metal or an alloy containing an alkali metal. Specifically, when the alkali metal battery is a lithium metal battery, the negative electrode body 1 is at least one of a lithium metal (element or alloy) foil, mesh, and felt, wherein when the lithium metal is an alloy, it can be but is not limited to one of a lithium-magnesium alloy foil, a lithium-aluminum alloy foil, and a lithium-boron alloy. When the alkali metal battery is a sodium metal battery, the negative electrode body 1 is at least one of a sodium metal (element or alloy) foil, mesh, and felt. When the alkali metal battery is a magnesium metal battery, the negative electrode body 1 is at least one of a magnesium metal (element or alloy) foil, mesh, and felt.

[0069] In addition, when the negative electrode body 1 is a negative electrode body of an alkali metal battery, the thickness of the alkali metal substrate can be a conventional or improved thickness of the alkali metal negative electrode sheet contained in the alkali metal battery.

[0070] When the negative electrode body 1 is a negative electrode body of an alkali metal ion battery or an alkali metal ion / alkali metal hybrid battery, it can also be a negative electrode body 1 as shown in Figures 2 to 4 Figure 1, comprising a current collector 11 and a negative electrode material layer 12 combined at least on one surface of the current collector 11, then the alkali metalizable layer 2 is directly laminated and combined on the outer surface of the negative electrode material layer 12. Moreover, the material of the negative electrode material layer 12 can be a negative electrode material layer contained in the corresponding alkali metal ion battery. For example, when the alkali metal ion battery is a lithium ion battery or the alkali metal ion / alkali metal hybrid battery is a lithium ion / lithium metal hybrid battery, the negative electrode material contained in the negative electrode material layer 12 includes a lithiumizable active material, such as the lithiumizable active material can be but not limited to at least one of graphite, hard carbon, lithium titanate, silicon, etc.; when the alkali metal ion battery is a sodium ion battery or the alkali metal ion / alkali metal hybrid battery is a sodium ion / sodium metal hybrid battery, the negative electrode material contained in the negative electrode material layer 12 includes a sodiumizable active material, such as the sodiumizable active material can be but not limited to at least one of hard carbon, titanium dioxide, molybdenum disulfide, manganese dioxide, copper oxide, iron oxide; when the alkali metal ion battery is a magnesium ion battery or the alkali metal ion / alkali metal hybrid battery is a magnesium ion / magnesium metal hybrid battery, the negative electrode material contained in the negative electrode material layer 12 includes a magnesiumizable active material, such as the magnesiumizable active material can be but not limited to at least one of magnesium titanate, titanium dioxide, molybdenum disulfide, manganese dioxide, copper oxide, iron oxide.

[0071] When the negative electrode body 1 is a negative electrode body of an alkali metal ion battery or an alkali metal ion / alkali metal hybrid battery, the negative electrode material layer 12 contained in the negative electrode body 1 can contain a conductive agent and a binder, etc. in addition to any of the above-mentioned lithiumizable active material, sodiumizable active material, magnesiumizable active material. The thickness of the negative electrode material layer 12 can be a conventional or improved thickness.

[0072] When the above-mentioned negative electrode body 1 is a structure as shown in Figures 2 to 4 Figure 1 containing a current collector 11, the material of the current collector 11 can be a negative electrode current collector material used for the negative electrode, and the appearance of the current collector 11 includes at least any one of a foil, a mesh, a felt. When the appearance of the current collector 11 is a foil, the foil can be a copper-based foil material or a nickel foil, and specifically can be a commonly used copper foil or an improved product thereof, such as a copper foil with surface roughness modification, perforation, etc., with a thickness of 6 μm-15 μm.

[0073] When the current collector 11 is in the form of a felt, the felt is selected from carbon fiber non-woven fabric, carbon fiber non-woven fabric plated with copper on the surface, carbon fiber non-woven fabric plated with nickel on the surface, polymer non-woven fabric plated with copper or nickel on the surface (such as copper-plated polyimide non-woven fabric, copper-plated polyester fiber). The felt current collector 11 has excellent electrical conductivity, micro / nano fibers, high porosity, and a thickness of 10-200 μm. Preferably, the fiber surface is alkali metal repellant, such as lithium, sodium, and magnesium repellant, such as copper-plated or nickel-plated current collector 11.

[0074] Therefore, in the above-mentioned embodiments, the negative electrode has a layer of alkali metalizable layer 2 laminated and combined with the outer surface of the negative electrode material layer 12, which has low electronic conductivity relative to the negative electrode material layer 12 and has alkali metalizable characteristics and good alkali metal ion conductivity, which plays a role in repelling and uniformly distributing alkali metal ions, improves the migration efficiency of alkali metal ions, reduces the deposition of alkali metal in the charge and discharge cycle, and reduces the formation of dendrites; and the deposition of alkali metal 3 in the charge and discharge cycle can only occur in the negative electrode material layer 12 or at the interface between the negative electrode material layer 12 and the alkali metalizable layer 2, avoiding deposition on the outer surface of the alkali metalizable layer 2. The alkali metalizable layer 2 plays the role of a protective layer and a buffer layer, thereby improving the safety performance of the battery containing the negative electrode of the embodiments of the present application. In addition, the combination of the alkali metalizable layer 2 also avoids direct contact of the negative electrode body 1 with the electrolyte, thereby improving the stability of the electrochemical performance of the negative electrode and the electrolyte in the charge and discharge cycle.

[0075] Correspondingly, the embodiments of the present application also provide a preparation method of the above-mentioned negative electrode. The preparation method of the negative electrode comprises the following steps:

[0076] S01: providing a negative electrode body;

[0077] S02: forming an alkali metalizable layer on the outer surface of the negative electrode material layer of the negative electrode body, and the electronic conductivity of the formed alkali metalizable layer is lower than the electronic conductivity of the negative electrode material layer, and the alkali metalizable layer has alkali metal ion conductivity.

[0078] In step S01, the provided negative electrode body is the negative electrode body 1 contained in the negative electrode of the embodiments of the present application described above. Therefore, the provided negative electrode body can be a negative electrode of an alkali metal battery or an alkali metal ion battery or an alkali metal ion / alkali metal hybrid battery. For example, it can be a negative electrode body 1 containing a current collector 11 and a negative electrode material layer 12 as shown in the figure, or it can be an alkali metal substrate negative electrode without a current collector. Figures 2 to 4

[0079] The alkali metalizable layer formed on the outer surface of the negative electrode material layer in step S02 is the alkali metalizable layer 2 contained in the negative electrode of the embodiments of the present application described above, and the types of components, thickness, etc. contained in the alkali metalizable layer are as described above.​

[0080] Therefore, the method of forming the alkali-metalizable layer on the outer surface of the negative electrode material layer in step S02 is any method of forming a film layer of the material of the alkali-metalizable layer 2 contained in the negative electrode of the above embodiment of the application on the outer surface of the negative electrode material layer, and is within the scope of the embodiment of the application, such as a conventional film forming method or a film forming method improved from a conventional film forming method. Therefore, the method of forming the alkali-metalizable layer on the outer surface of the negative electrode material layer at least includes the following methods:

[0081] In the embodiment, the method of forming the alkali-metalizable layer on the outer surface of the negative electrode material layer includes the following steps:

[0082] The alkali-metalizable material and the binder are formulated into a slurry with a solvent, the slurry is formed into a wet film layer on the outer surface of the negative electrode material layer of the negative electrode body, and the alkali-metalizable layer is formed after drying treatment.

[0083] In another embodiment, the method of forming the alkali-metalizable layer on the outer surface of the negative electrode material layer includes the following steps:

[0084] The alkali-metalizable material and the binder are formulated into a slurry with a solvent, the slurry is formed into a wet film layer on the outer surface of the negative electrode material layer of the negative electrode body, and the alkali-metalizable layer is formed after drying treatment.

[0085] In another embodiment, the method of forming the alkali-metalizable layer on the outer surface of the negative electrode material layer includes the following steps:

[0086] The alkali-metalizable material is deposited on the outer surface of the negative electrode material layer of the negative electrode body by a gas phase deposition method to form the alkali-metalizable layer.

[0087] In the above embodiment of the method of forming the alkali-metalizable layer, the alkali-metalizable material is the alkali-metalizable material contained in the alkali-metalizable layer 2 of the negative electrode of the above embodiment of the application. In the two embodiments of the method of forming the alkali-metalizable layer by using a slurry, the type and content of the binder are also the type and content of the binder contained in the alkali-metalizable layer 2 of the negative electrode of the above embodiment of the application. The solvent can be a solvent capable of effectively dispersing the alkali-metalizable material or dissolving the binder, such as but not limited to N-methyl pyrrolidone. In the embodiment of the method of forming the alkali-metalizable layer by using a gas phase deposition method, the method can be a chemical vapor deposition method or a physical vapor deposition method.

[0088] Therefore, the above negative electrode preparation method directly forms the alkali-metalizable layer on the outer surface of the negative electrode material layer of the negative electrode body, so that the prepared negative electrode has the excellent safety performance and electrochemical performance of the above negative electrode of the embodiment of the application, and the process conditions of the preparation method are easy to control, the performance and quality of the prepared negative electrode are stable, and the efficiency is high.

[0089] On the other hand, based on the above negative electrode and the preparation method thereof, the embodiment of the application further provides a battery. The lithium battery comprises a positive electrode, a negative electrode, and a separator stacked between the positive electrode and the negative electrode, and of course further comprises other components necessary for the lithium metal battery, such as an electrolyte or an electrolyte, and a shell. Among them, the negative electrode is the above negative electrode of the embodiment of the application. Since the battery contains the above negative electrode of the embodiment of the application, the battery not only has high capacity, but also has stable electrochemical performance, high safety, and long service life during the charge and discharge cycle, thereby expanding the application field of the lithium metal battery.

[0090] Based on the structure of the above negative electrode of the embodiment of the application and the types of the negative electrode material layer 12 contained in the negative electrode body 1 and the alkali-metalizable material contained in the alkali-metalizable layer 2 of the negative electrode, the battery of the embodiment of the application can be at least the following types of batteries:

[0091] The first type of battery: the negative electrode body 1 contained in the above negative electrode of the embodiment of the application is a lithium metal battery negative electrode, and the alkali-metalizable material contained in the alkali-metalizable layer 2 of the negative electrode is a lithiumizable material. At this time, the battery of the embodiment of the application is a lithium metal battery.

[0092] The second type of battery: the negative electrode body 1 contained in the above negative electrode of the embodiment of the application is a lithium ion battery negative electrode, and the alkali-metalizable material contained in the alkali-metalizable layer 2 of the negative electrode is a lithiumizable material. At this time, the battery of the embodiment of the application is a lithium ion battery.

[0093] The third type of battery: the negative electrode body 1 contained in the above negative electrode of the embodiment of the application is a negative electrode of a lithium ion / lithium metal hybrid battery, and the alkali-metalizable material contained in the alkali-metalizable layer 2 of the negative electrode is a lithiumizable material. At this time, the battery of the embodiment of the application is a lithium ion / lithium metal hybrid battery.

[0094] The fourth type of battery: the negative electrode body 1 contained in the above negative electrode of the embodiment of the application is a sodium metal battery negative electrode, and the alkali-metalizable material contained in the alkali-metalizable layer 2 of the negative electrode is a sodiumizable material. At this time, the battery of the embodiment of the application is a sodium metal battery.

[0095] The fifth battery type: the negative electrode body 1 contained in the negative electrode of the above-mentioned embodiment of the present application is a negative electrode of a sodium ion battery, and the alkali metalizable material contained in the alkali metalizable layer 2 contained in the negative electrode is a sodium metalizable material. At this time, the battery of the embodiment of the present application is a sodium ion battery.

[0096] The sixth battery type: the negative electrode body 1 contained in the negative electrode of the above-mentioned embodiment of the present application is a negative electrode of a sodium ion / sodium metal hybrid battery, and the alkali metalizable material contained in the alkali metalizable layer 2 contained in the negative electrode is a sodium metalizable material. At this time, the battery of the embodiment of the present application is a sodium ion / sodium metal hybrid battery.

[0097] The seventh battery type: the negative electrode body 1 contained in the negative electrode of the above-mentioned embodiment of the present application is a negative electrode of a magnesium metal battery, and the alkali metalizable material contained in the alkali metalizable layer 2 contained in the negative electrode is a magnesium metalizable material. At this time, the battery of the embodiment of the present application is a magnesium metal battery.

[0098] The eighth battery type: the negative electrode body 1 contained in the negative electrode of the above-mentioned embodiment of the present application is a negative electrode of a magnesium ion battery, and the alkali metalizable material contained in the alkali metalizable layer 2 contained in the negative electrode is a magnesium metalizable material. At this time, the battery of the embodiment of the present application is a magnesium ion battery.

[0099] The ninth battery type: the negative electrode body 1 contained in the negative electrode of the above-mentioned embodiment of the present application is a negative electrode of a magnesium ion / magnesium metal hybrid battery, and the alkali metalizable material contained in the alkali metalizable layer 2 contained in the negative electrode is a magnesium metalizable material. At this time, the battery of the embodiment of the present application is a magnesium ion / magnesium metal hybrid battery.

[0100] Each of the above-mentioned battery types contains the negative electrode of the above-mentioned embodiment of the present application, and therefore, each type of battery has high capacity, stable electrochemical performance during charge and discharge cycles, high safety, and long service life. Among them, it is ideal for each of the above-mentioned batteries that the alkali metalizable layer 2 contained in the negative electrode is arranged opposite to the separator.

[0101] The following will illustrate the flexible composite lithium metal electrode and its preparation method and lithium metal battery of the embodiment of the present application by means of a plurality of specific embodiments. The "~" in each of the following embodiments represents the meaning of about, such as ~ 16 μm, which represents about 16 μm.

[0102] I. Negative electrode and its preparation method embodiment

[0103] Embodiment A1

[0104] The embodiment provides a lithium titanate modified lithium metal electrode and a preparation method thereof. The lithium titanate modified lithium metal electrode comprises a copper-plated carbon felt current collector and lithium-magnesium foils filled in the copper-plated carbon felt current collector and lithium-magnesium foil layers distributed on the surface of the copper-plated carbon felt current collector, wherein an alkali metalizable layer is laminated on the outer surface of one lithium-magnesium foil layer, and the alkali metalizable layer comprises a mixture of lithium titanate and a binder.

[0105] The preparation method of the lithium titanate modified lithium metal negative electrode comprises the following steps.

[0106] S1. According to the mass ratio of 9:1 of lithium titanate and binder, mix nano lithium titanate powder and 6 wt% polyvinylidene fluoride N-methyl pyrrolidone solution, and scrape on a glass plate with a scraping interval of 50 μm. Cover the copper-plated carbon felt (thickness of 100 μm) on the surface of the scraped lithium titanate slurry. Then transfer the glass plate covered with copper-plated carbon felt to deionized water to perform phase inversion, to obtain a lithium titanate asymmetric conductive fiber felt current collector with a single-side loaded lithium titanate layer, and dry in a vacuum oven at 100°C.

[0107] S2. Stack the copper-plated carbon felt current collector prepared in step S1 and the lithium-magnesium foil according to the stacking order of lithium titanate layer / copper-plated carbon felt / lithium-magnesium foil, to obtain a lithium titanate modified lithium metal negative electrode precursor.

[0108] S3. Adjust the distance between the two rollers of the roller press to 100 μm, and roll the lithium metal negative electrode precursor stacked in sequence in step S2 to obtain a lithium metal electrode with a single-side surface containing a lithium titanate modified alkali metalizable layer with a thickness of about 90 μm.

[0109] Embodiment A2

[0110] The embodiment provides a lithium titanate modified lithium metal electrode and a preparation method thereof. The lithium titanate modified lithium metal electrode comprises a copper foil current collector and a lithium-magnesium foil layer laminated on one side surface of the copper foil current collector and an alkali metalizable layer laminated on the outer surface of the lithium-magnesium foil layer, wherein the alkali metalizable layer comprises a mixture of lithium titanate and a binder. The structure is copper foil current collector / lithium-magnesium foil layer / alkali metalizable layer.

[0111] The preparation method of the lithium titanate modified lithium metal negative electrode comprises the following steps.

[0112] S1. According to the mass ratio of 9:1 of lithium titanate and binder, mix nano lithium titanate powder and 6 wt% polyvinylidene fluoride N-methyl pyrrolidone solution, and scrape on a glass plate with a scraping interval of 50 μm. Cover the copper-plated carbon felt (thickness of 100 μm) on the surface of the scraped lithium titanate slurry. Then transfer the glass plate covered with copper-plated carbon felt to deionized water to perform phase inversion, to obtain a lithium titanate asymmetric conductive fiber felt current collector with a single-side loaded lithium titanate layer, and dry in a vacuum oven at 100°C. -2 S1. According to the mass ratio of 9:1 of lithium titanate and binder, mix nano lithium titanate powder and 6 wt% polyvinylidene fluoride N-methyl pyrrolidone solution, and scrape on a glass plate with a scraping interval of 50 μm. Cover the copper-plated carbon felt (thickness of 100 μm) on the surface of the scraped lithium titanate slurry. Then transfer the glass plate covered with copper-plated carbon felt to deionized water to perform phase inversion, to obtain a lithium titanate asymmetric conductive fiber felt current collector with a single-side loaded lithium titanate layer, and dry in a vacuum oven at 100°C.

[0113] S2. A 60 μm thick lithium-magnesium foil, a 10 μm thick copper foil, and the composite electrode tab of the lithium titanate layer / copper foil in step S1 were sequentially stacked in the order of copper foil / lithium titanate layer / lithium-magnesium foil / copper foil to obtain a lithium metal negative electrode precursor of the lithium titanate-modified lithium metal negative electrode in which the composite electrode tab in S1 was sequentially stacked with the lithium-magnesium foil and another copper foil;

[0114] S3. The lithium metal negative electrode precursor sequentially stacked in step S2 was rolled by adjusting the distance between the two rollers of the roller press to 80 μm to obtain a four-layer composite of copper foil / lithium titanate layer / lithium-magnesium foil / copper foil sequentially stacked with a thickness of about 80 μm; and the copper foil on the side of the lithium titanate layer was removed to obtain a lithium metal electrode of a lithium titanate layer / lithium-magnesium foil / copper foil three-layer composite structure in which the single-side surface of the lithium metal electrode contained a lithium-metalizable layer-modified lithium metal electrode containing lithium titanate.

[0115] Example A3

[0116] The present example provides an iron oxide-modified lithium metal electrode and a method for preparing the same. The iron oxide-modified lithium metal electrode includes a nickel-coated carbon felt current collector and lithium foils filled in the nickel-coated carbon felt current collector and a lithium foil layer distributed on the surface of the nickel-coated carbon felt current collector, and a lithium-metalizable layer containing a mixture of iron oxide and a binder is stacked on the outer surface of one of the lithium foil layers.

[0117] The method for preparing the iron oxide-modified lithium metal negative electrode includes the following steps:

[0118] S1. A nano-iron oxide powder and a 6 wt% polyvinylidene fluoride solution in N-methylpyrrolidone were mixed in a ratio of 19:1 by mass of iron oxide to binder, and were blade-coated on a glass plate with a coating gap of 100 μm. A nickel-coated carbon felt (100 μm thick) was placed on the surface of the iron oxide slurry after coating. The glass plate on which the nickel-coated carbon felt was placed was then transferred to deionized water to undergo phase inversion to obtain an asymmetric nickel-coated fiber felt loaded with iron oxide (3-4 mg cm -2 ) on one side, which was dried in a vacuum oven at 100°C;

[0119] S2. A 50 μm thick lithium foil was stacked on the nickel-coated carbon felt prepared in step S1 in the order of iron oxide layer / nickel-coated carbon felt / lithium foil to obtain an iron oxide-modified lithium metal negative electrode precursor;

[0120] S3. The lithium metal negative electrode precursor sequentially stacked in step S2 was rolled by adjusting the distance between the two rollers of the roller press to 100 μm to obtain a lithium metal electrode of a lithium-metalizable layer-modified lithium metal electrode containing iron oxide on the single-side surface with a thickness of about 90 μm.

[0121] Example A4

[0122] The present embodiment provides a titanium dioxide modified lithium metal electrode and a preparation method thereof. The titanium dioxide modified lithium metal electrode comprises a copper-plated polyimide felt current collector and lithium foils filled in the copper-plated polyimide felt and lithium foil layers distributed on the surface of the copper-plated polyimide felt current collector, and an alkali metalizable layer is laminated on the outer surface of one lithium foil layer, wherein the alkali metalizable layer comprises a mixture of titanium dioxide and a binder.

[0123] The preparation method of the titanium dioxide modified lithium metal negative electrode comprises the following steps:

[0124] S1. Mix nano-titanium dioxide powder and a 6 wt% polyvinylidene fluoride solution in N-methyl pyrrolidone at a mass ratio of titanium dioxide to binder of 19:1, and perform blade coating on a glass plate with a coating gap controlled at 100 μm. A copper-plated polyimide felt (100 μm thick) is covered on the surface of the titanium dioxide slurry after coating. Then, the glass plate covered with the copper-plated polyimide felt is transferred to deionized water to undergo phase inversion, thereby obtaining an asymmetric copper-plated polyimide felt loaded with titanium dioxide (3-4 mg cm -2 ) on one side, which is dried in a vacuum oven at 100 degrees.

[0125] S2. Stack the copper-plated polyimide felt prepared in step S1 and a 50 μm thick lithium foil in the order of titanium dioxide layer / copper-plated polyimide felt / lithium foil, thereby obtaining a titanium dioxide modified lithium metal negative electrode precursor.

[0126] S3. Adjust the distance between the two rollers of a roller press to 100 μm, and roll the lithium metal negative electrode precursor stacked in order in step S2, thereby obtaining a lithium metal electrode modified with an alkali metalizable layer containing titanium dioxide on one side surface, with a thickness of about 90 μm.

[0127] Embodiment A5

[0128] The present embodiment provides a lithium titanate modified lithium metal electrode and a preparation method thereof. The lithium titanate modified lithium metal electrode comprises a copper-plated carbon felt current collector and lithium-magnesium foils filled in the copper-plated carbon felt current collector and lithium-magnesium foil layers distributed on the surface of the copper-plated carbon felt current collector, and an alkali metalizable layer is laminated on the outer surface of each of the two lithium-magnesium foil layers, wherein the alkali metalizable layer comprises a mixture of lithium titanate and a binder.

[0129] The preparation method of the lithium titanate modified lithium metal negative electrode comprises the following steps:

[0130] S1. Mix nano-lithium titanate powder and 6 wt% polyvinylidene fluoride solution in N-methyl pyrrolidone according to the mass ratio of lithium titanate to binder of 9:1, and then coat on a glass plate with a doctor blade gap of 50 μm. Cover the lithium titanate slurry surface with copper-plated carbon felt (100 μm thick) after coating. Then transfer the glass plate covered with copper-plated carbon felt to deionized water for phase inversion to obtain a lithium titanate asymmetric conductive fiber felt current collector with a single-side loaded lithium titanate layer, and dry in a vacuum oven at 100°C.

[0131] S2. Stack the copper-plated carbon felt current collector prepared in step S1 and lithium-magnesium foil according to the stacking order of lithium titanate layer / copper-plated carbon felt / lithium-magnesium foil / lithium titanate layer to obtain a lithium titanate modified lithium metal negative electrode precursor.

[0132] S3. Adjust the distance between the two rollers of the roller press to 140 μm, and roll the lithium metal negative electrode precursor stacked in order in step S2 to obtain a lithium metal electrode with a thickness of about 140 μm, which contains a lithium titanate-containing alkali metalizable layer on both surfaces.

[0133] Example A6

[0134] The present embodiment provides a lithium metal / lithium ion hybrid negative electrode and a preparation method thereof. The lithium metal / lithium ion hybrid negative electrode comprises a copper-plated foil current collector and a negative electrode active layer combined on the surface of the copper foil current collector, and an alkali metalizable layer is combined on the outer surface of the negative electrode active layer, wherein the alkali metalizable layer contains a mixture of lithium titanate and a binder.

[0135] The preparation method of the lithium metal / lithium ion hybrid negative electrode comprises the following steps:

[0136] S1: First, mix graphite 94%, conductive agent 4%, and binder 2% to prepare an active material slurry, and then coat the electrode on a copper foil with a doctor blade gap of 100 μm. The graphite active material loading is about 4-5 mg / cm 2 , and dry for later use to obtain a negative electrode body;

[0137] S2: Mix nano-lithium titanate powder and 6 wt% polyvinylidene fluoride solution in N-methyl pyrrolidone according to the mass ratio of lithium titanate to binder of 9:1, and then coat on the negative electrode body (i.e., coat on the surface of the graphite), with a doctor blade gap of 50 μm. Dry to obtain a negative electrode with an alkali metalizable layer containing lithium titanate on the surface.

[0138] Example A7

[0139] The present embodiment provides a titanium dioxide modified sodium metal electrode and a preparation method thereof. The titanium dioxide modified sodium metal electrode comprises a copper-plated carbon felt current collector and sodium foils filled in the copper-plated carbon felt current collector and sodium foil layers distributed on the surface of the copper-plated carbon felt current collector, wherein an alkali metalizable layer is laminated on the outer surface of one of the sodium foil layers, and the alkali metalizable layer comprises a mixture of titanium dioxide and a binder.

[0140] The preparation method of the titanium dioxide lithium metal negative electrode comprises the following steps:

[0141] S1. Mix nano-titanium dioxide powder and a 6 wt% polyvinylidene fluoride solution in N-methyl pyrrolidone at a mass ratio of titanium dioxide to binder of 9:1, and perform blade coating on a glass plate, with a coating gap controlled to be 50 μm. A copper-plated carbon felt (100 μm thick) is covered on the surface of the titanium dioxide slurry after coating. Then, the glass plate covered with the copper-plated carbon felt is transferred to deionized water to perform phase inversion, to obtain a titanium dioxide asymmetric conductive fiber felt current collector with a single-side loaded titanium dioxide layer, which is dried in a vacuum oven at 100°C.

[0142] S2. Stack the copper-plated carbon felt current collector prepared in step S1 and a 100 μm thick sodium foil in the order of titanium dioxide layer / copper-plated carbon felt / sodium foil, to obtain a titanium dioxide modified sodium metal negative electrode precursor.

[0143] S3. Adjust the distance between the two rollers of a roller press to 180 μm, and roll the sodium metal negative electrode precursor stacked in order in step S2, to obtain a sodium metal electrode with an insulating alkali metalizable layer modified with titanium dioxide on the surface, with a thickness of about 180 μm.

[0144] Embodiment A8

[0145] The present embodiment provides a sodium metal / sodium ion hybrid negative electrode and a preparation method thereof. The sodium metal / sodium ion hybrid negative electrode comprises a copper-plated foil current collector and a negative electrode active layer combined on the surface of the copper foil current collector, and an alkali metalizable layer is combined on the outer surface of the negative electrode active layer, wherein the alkali metalizable layer comprises a mixture of titanium dioxide and a binder.

[0146] The preparation method of the sodium metal / sodium ion hybrid negative electrode comprises the following steps:

[0147] S1: first, prepare an active material slurry in a proportion of 94% lithium-embeddable material titanium dioxide, 4% conductive agent, and 2% binder, and perform blade coating on an aluminum foil with a coating gap controlled to be 100 μm, so that the loading of the titanium dioxide active material is about 6-8 mg / cm 2 , and then dry the same to obtain a negative electrode body;

[0148] S2: Mixing nano-titanium dioxide powder and 6 wt% polyvinylidene fluoride N-methyl pyrrolidone solution in the ratio of 9:1 of titanium dioxide to binder, scraping on the negative electrode body (i.e. scraping on the surface of the titanium dioxide active layer), scraping interval controlled at 50 μm, after drying, obtaining a negative electrode with a surface containing a titanium dioxide alkali metalizable layer modified electrode.

[0149] Example A9

[0150] The present example provides a titanium dioxide modified magnesium metal electrode and a preparation method thereof. The titanium dioxide modified magnesium metal electrode comprises a copper-plated carbon felt current collector and magnesium foils filled in the copper-plated carbon felt current collector and magnesium foil layers distributed on the surface of the copper-plated carbon felt current collector, wherein the outer surface of one magnesium foil layer is laminated with an alkali metalizable layer containing a mixture of titanium dioxide and a binder.

[0151] S1. Mixing nano-titanium dioxide powder and 6 wt% polyvinylidene fluoride N-methyl pyrrolidone solution in the ratio of 9:1 of titanium dioxide to binder, scraping on a glass plate, scraping interval controlled at 50 μm, covering the scraped titanium dioxide slurry surface with copper-plated carbon felt (thickness of 100 μm); then transferring the glass plate covered with copper-plated carbon felt into deionized water to undergo phase inversion, obtaining a titanium dioxide asymmetric conductive fiber felt current collector with a single-side loaded titanium dioxide layer, drying in a vacuum oven at 100°C;

[0152] S2. Laminating the copper-plated carbon felt current collector and magnesium foils prepared in step S1 in the order of titanium dioxide layer / copper-plated carbon felt / magnesium foil to obtain a titanium dioxide modified magnesium metal negative electrode precursor;

[0153] S3. Adjusting the distance between the two rollers of the roller press to 180 μm, and rolling the magnesium metal negative electrode precursor laminated in order in step S2 to obtain a magnesium metal electrode with a surface containing an alkali metalizable layer modified electrode with a thickness of about 180 μm.

[0154] Example A10

[0155] The present example provides a magnesium metal / magnesium ion hybrid negative electrode and a preparation method thereof. The magnesium metal / magnesium ion hybrid negative electrode comprises a copper-plated foil current collector and a negative electrode active layer combined on the surface of the copper foil current collector, and an alkali metalizable layer combined on the outer surface of the negative electrode active layer, wherein the alkali metalizable layer contains a mixture of titanium dioxide and a binder.

[0156] The preparation method of the sodium metal / ion hybrid negative electrode comprises the following steps:

[0157] S1: First, prepare active material slurry by mixing lithium-embeddable material titanium dioxide 94%, conductive agent 4%, and binder 2% in a ratio of 94:4:2, and then coat the electrode on an aluminum foil with a gap of 100 μm. The active material of titanium dioxide has a load of about 6-8 mg / cm2. 2 After drying, the negative electrode body is obtained.

[0158] Mix nano-titanium dioxide powder and 6 wt% polyvinylidene fluoride N-methyl pyrrolidone solution in a ratio of 9:1 of titanium dioxide to binder, and then coat the negative electrode body (i.e., coat the surface of the titanium dioxide active layer) with a gap of 50 μm. After drying, the negative electrode with an alkali metalizable layer modified by titanium dioxide is obtained.

[0159] Comparative Example A1

[0160] A lithium-magnesium foil electrode with a thickness of about 60 μm is provided.

[0161] Comparative Example A2

[0162] A thick lithium foil electrode with a thickness of about 50 μm is provided.

[0163] Comparative Example A3

[0164] The present comparative example provides a conductive graphite modified lithium metal electrode and a method for preparing the same. The structure and material of the conductive graphite modified lithium metal electrode are the same as those of Example A1, except that a conductive modification layer containing a mixture of graphite and a binder is laminated on the outer surface of one lithium-magnesium foil layer.

[0165] The method for preparing a lithium titanate modified lithium metal negative electrode comprises the following steps:

[0166] S1. Mix graphite powder and 6 wt% polyvinylidene fluoride N-methyl pyrrolidone solution in a ratio of 9:1 of graphite to binder, and then coat on a glass plate with a gap of 50 μm. Cover the surface of the coated graphite slurry with a copper-plated carbon felt (thickness of 100 μm), and then transfer the glass plate covered with the copper-plated carbon felt to deionized water to undergo phase inversion, thereby obtaining a lithium titanate asymmetric conductive fiber felt current collector loaded with a single-side lithium titanate layer. Dry in a vacuum oven at 100°C.

[0167] S2. Stack the copper-plated carbon felt current collector prepared in step S1 and the lithium-magnesium foil in the order of conductive graphite layer / copper-plated carbon felt / lithium-magnesium foil to obtain a conductive graphite modified lithium metal negative electrode precursor.

[0168] S3. Adjust the distance between the two rollers of the roller press to 100 pm, and roll the lithium metal negative electrode precursor sequentially stacked in step S2 to obtain a lithium metal electrode with a conductive modification layer containing conductive graphite on one side surface, with a thickness of about 90 pm.

[0169] Comparative Example A4

[0170] The present comparative example provides a silicon-modified lithium metal electrode and a method for preparing the same. The silicon-modified lithium metal electrode includes a copper foil current collector and a lithium-magnesium foil layer laminated on one side surface of the copper foil current collector, and a silicon modification layer laminated on the outer surface of the lithium-magnesium foil layer, the silicon modification layer containing a mixture of silicon and a binder. The structure is copper foil current collector / lithium-magnesium foil layer / silicon modification layer.

[0171] The method for preparing the silicon-modified lithium metal negative electrode includes the following steps:

[0172] S1. Mix the nano lithium titanate powder and a 6 wt% polyvinylidene fluoride solution in N-methyl pyrrolidone at a ratio of 9:1 by mass ratio of nano silicon powder to binder, and coat a film on a flat 10 pm thick copper foil at a coating distance of 50 pm. After coating, dry the solvent in a vacuum oven at 100°C to obtain a silicon / copper foil composite electrode with a silicon loading of 0.8-1 mg cm -2 ;

[0173] S2. Stack the 60 pm thick lithium-magnesium foil, 10 pm thick copper foil, and the silicon / copper foil composite electrode of step S1 in the order of copper foil / silicon layer / lithium-magnesium foil / copper foil, and sequentially laminate the composite electrode of step S1 with the lithium-magnesium foil and another copper foil to obtain a silicon-modified lithium metal negative electrode precursor;

[0174] S3. Adjust the distance between the two rollers of the roller press to 80 pm, and roll the lithium metal negative electrode precursor sequentially stacked in step S2 to obtain a four-layer composite of copper foil / silicon layer / lithium-magnesium foil / copper foil with a thickness of about 80 pm; then remove the copper foil on the side of the silicon layer, and the remaining three-layer composite structure of silicon layer / lithium-magnesium foil / copper foil has a silicon-modified lithium metal electrode with a silicon modification layer on one side surface.

[0175] II. Battery Examples

[0176] Examples B1-B10 and Comparative Examples B1-B4

[0177] The present examples B1-B10 provide a battery. The battery includes the following structure:

[0178] Positive electrode:

[0179] Lithium battery positive electrode: active material is NCM811 (about 18 mg cm -2positive electrode with active material of NCM811 (loading about 22 mg cm -2 ) was cut into a 12 mm diameter electrode piece;

[0180] Lithium metal / lithium ion battery positive electrode: positive electrode with active material of NCM811 (loading about 22 mg cm -2 ) was cut into a 12 mm diameter electrode piece;

[0181] Sodium battery positive electrode: positive electrode with active material of Na3V2(PO4)3 (loading about 16 mg cm -2 ) was cut into a 12 mm diameter electrode piece;

[0182] Sodium metal / ion battery positive electrode: positive electrode with active material of Na3V2(PO4)3 (loading about 20 mg cm -2 ) was cut into a 12 mm diameter electrode piece;

[0183] Magnesium battery positive electrode: positive electrode with active material of V2O5 (loading about 10 mg cm -2 ) was cut into a 12 mm diameter electrode piece;

[0184] Magnesium ion battery positive electrode: positive electrode with active material of V2O5 (loading about 15 mg cm -2 ) was cut into a 12 mm diameter electrode piece;

[0185] Negative electrode: negative electrode provided by Examples A1 to A10 and negative electrode provided by Comparative Examples A1 to A4, respectively, wherein the negative electrode provided by Examples A1 to A5 and the negative electrode provided by Comparative Examples A1 to A4, respectively, were cut into a 14 mm diameter circular piece;

[0186] Separator: celgard2400 type separator;

[0187] Electrolyte:

[0188] Lithium battery ester electrolyte: main component is 1M LiPF6 dissolved in a mixed electrolyte of EC, DMC and FEC, EC / DMC = 3:7, FEC content is 10wt%;

[0189] Sodium battery electrolyte: main component is 1M NaPF6 dissolved in a mixed electrolyte of EC, DMC and FEC, EC / DMC = 3:7, FEC content is 10wt%;

[0190] Magnesium battery electrolyte: 1M MgFPA (molecular formula Mg2Cl3·6THF [Al(O2C2(CF3)4)2]·THF) dissolved in tetrahydrofuran THF;

[0191] Assembly: Assembling the coin cell battery respectively with the positive electrode, negative electrode, separator and electrolyte. Specifically, the above lithium battery positive electrode, the negative electrode provided by the negative electrode provided by the lithium battery ester electrolyte of Example A1 to Example A5 and Comparative Example A1 to Comparative Example A4 is assembled into the negative electrode of Example B1 to Example B5 and Comparative Example B1 to Comparative Example B4. CR2025 coin lithium metal battery.

[0192] The above lithium ion battery positive electrode, the negative electrode provided by Example A6, and the lithium battery ester electrolyte are assembled into a lithium metal / lithium ion hybrid battery of the coin 2025 type in Example B6.

[0193] The above sodium battery positive electrode, the negative electrode provided by Example A7, and the sodium battery electrolyte are assembled into a coin 2025 type metal sodium battery in Example B7.

[0194] The above sodium ion battery positive electrode, the negative electrode provided by Example A8, and the sodium battery electrolyte are assembled into a coin 2025 type sodium metal / sodium ion hybrid battery in Example B8.

[0195] The above magnesium battery positive electrode, the negative electrode provided by Example A9, and the magnesium battery electrolyte are assembled into a coin 2025 type metal magnesium battery in Example B9.

[0196] The above magnesium ion battery positive electrode, the negative electrode provided by Example A10, and the magnesium battery electrolyte are assembled into a coin 2025 type magnesium metal / magnesium ion hybrid negative electrode battery in Example B10.

[0197] Among the above batteries, the alkali metalizable layer contained in the negative electrode is attached to the separator.

[0198] III. Related property tests

[0199] After the batteries provided by Example B1 to Example B10 and Comparative Example B1 to Comparative Example B4 are assembled and stand for 24 h, the voltage is qualified, and the cycle performance test is carried out respectively.

[0200] Among them, the cycle performance test conditions of Example B1 to Example B5 and Comparative Example B1 to Comparative Example B4 are: after 3 cycles of activation at a current density of 0.4 mA / cm 2 , the cycle charging and discharging is carried out at a current density of 1 mA / cm 2 .

[0201] The cycle performance test conditions for the lithium metal / lithium-ion battery provided in Example B6 are as follows: at 0.4 mA / cm 2 After activation at a current density of 3 cycles, then at 1 mA / cm² 2 It is subjected to cyclic charging and discharging at a current density.

[0202] The cycle performance test conditions for the sodium metal battery provided in Example B7 are as follows:

[0203] At 0.4 mA / cm 2 After activation at a current density of 3 cycles, then at 1 mA / cm² 2 It is subjected to cyclic charging and discharging at a current density.

[0204] The cycle performance test conditions for the sodium metal / sodium ion hybrid battery provided in Example B8 are as follows: at 0.4 mA / cm 2 After activation at a current density of 3 cycles, then at 1 mA / cm² 2 It is subjected to cyclic charging and discharging at a current density.

[0205] The cycle performance test conditions for the magnesium metal battery provided in Example B9 are as follows: at 0.4 mA / cm 2 After activation at a current density of 3 cycles, then at 1 mA / cm² 2 It is subjected to cyclic charging and discharging at a current density.

[0206] The cycle performance test conditions for the magnesium metal / magnesium ion hybrid battery provided in Example B10 are as follows: at 0.4 mA / cm 2 After activation at a current density of 3 cycles, then at 1 mA / cm² 2 It is subjected to cyclic charging and discharging at a current density.

[0207] Battery cycle performance test results:

[0208] The cycle performance test results of the lithium metal batteries provided in Example B1 and Comparative Example B3 are as follows: Figure 5 As shown. By Figure 5 It can be seen that the full cell with lithium metal electrode modified with lithium titanate as the negative electrode has a current density greater than 3 mAh / cm³ at 1 mA. 2 The lithium metal electrode in Example A1, with its areal capacity, maintained a capacity retention of over 70% after 250 cycles, demonstrating good cycle stability. In contrast, the full cell containing the conductive graphite-modified lithium metal electrode provided in Comparative Example B3 showed significant capacity decay after 80 cycles. Even the lithium-magnesium composite anode using only conductive fibers began to show significant capacity decay after 150 cycles, with a capacity retention of less than 50% after 200 cycles. These results indicate that the lithium metal electrode modified with lithium titanate as described in Example A1 is more stable than the conductive graphite-modified lithium metal electrode in Comparative Example A3.

[0209] The results of the lithium metal battery cycle performance test provided by Example B2 and Comparative Example B2 are shown in Table 2. Figure 6 As can be seen from Table 2, the full battery with the lithium metal electrode modified by lithium titanate as the negative electrode began to show capacity attenuation after 200 cycles at a current density of 1 mA; while the full battery with the pure lithium foil as the negative electrode began to show obvious capacity fluctuation attenuation after about 30 cycles (N / P < 3). The above results show that the cycle stability of the lithium metal negative electrode containing the lithium titanate modification in Example A2 is more stable than the pure lithium foil in Comparative Example A2. Figure 6 The results of the lithium metal battery cycle performance test provided by Example B3 and Comparative Example B4 are shown in Table 3.

[0210] As can be seen from Table 3, the full battery with the lithium metal electrode modified by iron oxide as the negative electrode in Example B3 began to show capacity attenuation after 170 cycles at a current density of 1 mA; while the full battery with the lithium negative electrode modified by silicon provided by Comparative Example B4 began to show obvious attenuation after 100 cycles. The above results show that the cycle stability of the lithium metal negative electrode containing the iron oxide modification in Example A3 is more stable than the lithium negative electrode modified by silicon in Comparative Example A4. Figure 7 Figure 7 The results of the lithium metal battery cycle performance test provided by Example B4 and Comparative Example B1 are shown in Table 4. As can be seen from Table 4, the full battery with the lithium metal electrode modified by titanium dioxide as the negative electrode in Example B4 began to show capacity attenuation after 200 cycles at a current density of 1 mA; while the full battery with the pure lithium-magnesium foil as the negative electrode provided by Comparative Example B1 began to show obvious attenuation after 80 cycles. The above results show that the cycle stability of the lithium metal negative electrode containing the titanium dioxide modification in Example A4 is more stable than the pure lithium-magnesium foil negative electrode in Comparative Example A1.

[0211] Figure 8 The lithium metal / lithium ion hybrid battery provided by Example B6 has a capacity retention of 83% after 200 cycles, and the only difference between Example B6 and the comparative lithium metal / lithium ion hybrid battery without the lithium titanate alkali metalizable layer is that the comparative lithium metal / lithium ion hybrid battery has a capacity retention of 48% after 100 cycles. Figure 8 The sodium metal battery provided by Example B7 has a capacity retention of 92% after 300 cycles, and the only difference between Example B7 and the comparative sodium metal battery without the titanium dioxide alkali metalizable layer is that the comparative sodium metal battery has a capacity retention of 52% after 200 cycles.

[0212] The magnesium metal / magnesium ion hybrid battery provided by Example B10 has a capacity retention of 91% after 1000 cycles, and the only difference between Example B10 and the comparative magnesium metal / magnesium ion hybrid battery without the titanium dioxide alkali metalizable layer is that the comparative magnesium metal / magnesium ion hybrid battery has a capacity retention of 68% after 500 cycles.

[0213] The magnesium metal / magnesium ion hybrid battery provided by Example B10 has a capacity retention of 91% after 1000 cycles, and the only difference between Example B10 and the comparative magnesium metal / magnesium ion hybrid battery without the titanium dioxide alkali metalizable layer is that the comparative magnesium metal / magnesium ion hybrid battery has a capacity retention of 68% after 500 cycles.

[0214] The magnesium metal / magnesium ion hybrid battery provided by Example B10 has a capacity retention of 91% after 1000 cycles, and the only difference between Example B10 and the comparative magnesium metal / magnesium ion hybrid battery without the titanium dioxide alkali metalizable layer is that the comparative magnesium metal / magnesium ion hybrid battery has a capacity retention of 68% after 500 cycles.​

[0215] From the above battery cycle performance test results, it can be seen that the cycle performance of the battery containing the alkali metalizable layer modified negative electrode is significantly improved, and the service life is obviously prolonged.

[0216] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement and improvement within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A negative electrode comprising a negative electrode body provided with a negative electrode material layer, characterized by: Further comprising an alkali-metalizable layer laminated on the outer surface of the negative electrode material layer, the alkali-metalizable layer having an electronic conductivity lower than that of the negative electrode material layer and having alkali metal ion conductivity; The material of the alkali-metalizable layer comprises an alkali-metalizable material, the alkali-metalizable material comprising at least one of lithium titanate, magnesium titanate, titanium dioxide, molybdenum disulfide, manganese dioxide, copper oxide, and iron oxide; The alkali-metalzable layer material includes the alkali-metalzable material and a binder mixed with the alkali-metalzable material, and the binder accounts for 0-50% of the weight of the alkali-metalzable material, and is not equal to 0; the conductivity x of the alkali-metalzable layer and the conductivity y of the negative electrode material layer satisfy: y / x≥10 3 .

2. The negative electrode according to claim 1, characterized by: The alkali-metalizable material is in a particle morphology, the particle having a sub-micron or / and nano particle size range; and / or The binder comprises at least one of polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyacrylic acid, and hydroxymethyl cellulose acetate.

3. The negative electrode according to any one of claims 1 to 2, characterized by: The thickness of the alkali-metalizable layer is 1 μm-50 μm; and / or The negative electrode body is a negative electrode of an alkali metal battery, a negative electrode of an alkali metal ion / alkali metal hybrid battery, or a negative electrode of an alkali metal ion battery.

4. The negative electrode according to claim 3, characterized by: The alkali metal material contained in the negative electrode of the alkali metal battery comprises at least one of lithium elemental substance and lithium alloy, and the alkali-metalizable material contained in the alkali-metalizable layer is a lithiumizable material; or The alkali metal material contained in the negative electrode of the alkali metal battery comprises at least one of sodium elemental substance and sodium alloy, and the alkali-metalizable material contained in the alkali-metalizable layer is a sodiumizable material; or The alkali metal material contained in the negative electrode of the alkali metal battery comprises at least one of magnesium elemental substance and magnesium alloy, and the alkali-metalizable material contained in the alkali-metalizable layer is a magnesiumizable material.

5. The method of producing a negative electrode according to any one of claims 1 to 4, characterized by, Comprising the following steps: Providing a negative electrode body; Forming an alkali-metalizable layer on the outer surface of the negative electrode material layer of the negative electrode body, the alkali-metalizable layer having an electronic conductivity lower than that of the negative electrode material layer and having alkali metal ion conductivity.

6. The method of claim 5, wherein: The method for forming an alkali-metalizable layer on the outer surface of the negative electrode material layer of the negative electrode body comprises the following steps: Preparation of a slurry of an alkali-metalizable material and a binder with a solvent, formation of a wet film layer of the slurry on the outer surface of the negative electrode material layer of the negative electrode body, and formation of the alkali-metalizable layer after drying treatment; or Preparation of a slurry of an alkali-metalizable material and a binder with a solvent, formation of the alkali-metalizable layer by film formation treatment of the slurry, and lamination of the alkali-metalizable layer on the outer surface of the negative electrode material layer of the negative electrode body. The negative electrode is the negative electrode of any one of claims 1-4 or prepared by the preparation method of any one of claims 5-6.

7. A battery comprising a positive electrode, a negative electrode, and a separator laminated between the positive electrode and the negative electrode, characterized by: The negative electrode body contained in the negative electrode is a lithium metal battery negative electrode, and the battery is a lithium metal battery; or 8. The battery of claim 7, wherein: The negative electrode body contained in the negative electrode is a lithium ion / lithium metal hybrid battery negative electrode, and the battery is a lithium ion / lithium metal hybrid battery; or The negative electrode body contained in the negative electrode is a lithium ion battery negative electrode, and the battery is a lithium ion battery; or The negative electrode body contained in the negative electrode is a sodium metal battery negative electrode, and the battery is a sodium metal battery; or ​ The negative electrode contains a negative electrode body that is a negative electrode of a sodium-ion / sodium-metal hybrid battery, and the battery is a sodium-ion / sodium-metal hybrid battery; or The negative electrode contains a negative electrode body that is a negative electrode of a sodium-ion battery, and the battery is a sodium-ion battery; or The negative electrode contains a negative electrode body that is a negative electrode of a magnesium-metal battery, and the battery is a magnesium-metal battery; or The negative electrode contains a negative electrode body that is a negative electrode of a magnesium-ion / magnesium-metal hybrid battery, and the battery is a magnesium-ion / magnesium-metal hybrid battery; or The negative electrode contains a negative electrode body that is a negative electrode of a magnesium-ion battery, and the battery is a magnesium-ion battery.

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