Lithium metal composite electrode materials and their preparation methods, as well as electrodes, batteries, battery modules, battery packs, and devices containing them.

Abstract

This invention provides a lithium metal composite electrode material for lithium metal batteries, its preparation method, and electrodes, batteries, battery modules, battery packs, and devices comprising the same. The lithium metal composite electrode material includes lithium metal particles and a lithium-containing conductive layer serving as a supporting framework, wherein the lithium metal particles are filled within the supporting framework; the lithium-containing conductive layer comprises inorganic lithium compounds and lithium alloys. This lithium metal composite electrode material addresses the problems of lithium metal as a negative electrode, such as easy consumption of electrolyte, easy formation of lithium dendrites, and deposition and dissolution leading to changes in electrode thickness, thus affecting battery cycle stability, electrical performance, and structural stability. It achieves the goal of improving the structural and cycle stability of lithium metal electrodes.

Description

[0001] This application is based on the invention with the application number 201911014994.1, the application date is October 24, 2019, the applicant is Ningde era new energy technology Co., Ltd., and the invention name is "lithium metal composite electrode material, its preparation method and electrode, battery, battery module, battery pack and device containing the same". TECHNICAL FIELD

[0002] The present application relates to the field of battery, in particular, to a lithium metal composite electrode material, a preparation method thereof and an electrode, a battery, a battery module, a battery pack and a device containing the same. BACKGROUND

[0003] Modern society widely uses portable chemical power sources. With the continuous development of high-tech, the energy density requirement of power supply system is also increasing, and high energy density secondary battery has become the focus of future energy industry development. Lithium ion battery has become the most widely used secondary battery system due to its outstanding performance advantages. However, the existing lithium ion battery often uses graphitized carbon material as negative electrode material, and the theoretical specific capacity is 370mAh / g. The energy density of the related battery cannot meet the needs of modern society. Especially the rapid development of electric vehicles and other vehicles, which urgently need secondary batteries with higher specific energy.

[0004] Lithium metal has the highest theoretical specific capacity (3860mAh / g) and the lowest electrode potential (-3.04V vs standard hydrogen electrode) in solid materials. Developing high energy density lithium metal-based secondary battery has become a research hotspot. However, there are three main problems in using lithium metal as negative electrode material: first, due to the high activity of lithium metal, and the non-uniformity of the solid electrolyte interface film formed on the surface, irreversible reaction with electrolyte is easily occurred during the cycle process, which consumes electrolyte and reduces the coulombic efficiency, eventually leading to battery failure. Second, lithium metal is easy to form dendrites during the cycle process. The lithium dendrites detached from the matrix cannot form electronic path and form "dead lithium", which will reduce the cycle efficiency of lithium electrode; if the lithium dendrites continue to grow, they will pierce the separator and cause short circuit, leading to thermal runaway of the battery, and even cause explosion and a series of safety problems. Third, the deposition and dissolution of lithium metal involve significant electrode thickness change, which affects the stability of the battery structure. SUMMARY

[0005] The first object of the present application is to provide a lithium metal composite electrode material for lithium metal battery, to solve the problems of lithium metal as negative electrode, such as easy consumption of electrolyte, easy production of lithium dendrites, and easy deposition and dissolution leading to electrode thickness change and affecting the cycle stability, electrical performance and structural stability of the battery.

[0006] The second object of the present application is to provide a preparation method of a lithium metal composite electrode material for a lithium metal battery, so as to solve the problems of easy consumption of electrolyte, easy generation of lithium dendrites, and easy deposition and dissolution of lithium when lithium metal is used as a negative electrode, which can easily lead to changes in electrode thickness and affect the cycle stability, electrical performance and structural stability of the battery.

[0007] The third object of the present application is to provide a lithium metal composite electrode for a lithium metal battery, comprising the lithium metal composite electrode material of the present application.

[0008] The fourth object of the present application is to provide a lithium metal battery comprising the lithium metal composite electrode of the present application.

[0009] The fifth object of the present application is to provide a battery module comprising the lithium metal battery of the present application.

[0010] The sixth object of the present application is to provide a battery pack comprising the battery module of the present application.

[0011] The seventh object of the present application is to provide a device comprising the lithium metal battery of the present application as a power source.

[0012] To achieve the above objects, the technical solutions adopted by the present application are as follows:

[0013] In a first aspect, the present application provides a lithium metal composite electrode material for a lithium metal battery, comprising:

[0014] lithium metal particles and a lithium-containing conductive layer as a support framework, the lithium metal particles being filled in the support framework; the lithium-containing conductive layer comprising inorganic lithium compounds and lithium alloys.

[0015] In a second aspect, the present application provides a preparation method of a lithium metal composite electrode material for a lithium metal battery, comprising the following steps:

[0016] filling lithium metal particles in a lithium-containing conductive layer as a support framework to obtain the lithium metal composite electrode material; wherein the lithium-containing conductive layer comprises inorganic lithium compounds and lithium alloys.

[0017] In a third aspect, the present application provides a lithium metal composite electrode for a lithium metal battery, comprising the lithium metal composite electrode material of the first aspect of the present application or the lithium metal composite electrode material obtained by the preparation method of the second aspect of the present application.

[0018] In a fourth aspect, the present application provides a lithium metal battery comprising the lithium metal composite electrode of the third aspect of the present application.

[0019] In a fifth aspect, the present application provides a battery module comprising the lithium metal battery of the fourth aspect of the present application.

[0020] In a sixth aspect, the present invention provides a battery pack including the battery module of the fifth aspect of the present invention.

[0021] In a seventh aspect, the present invention provides an apparatus that uses a lithium metal battery as a power source, including the battery pack of the sixth aspect of the present invention.

[0022] Compared with the prior art, the advantages of adopting the technical solution of the present invention are as follows:

[0023] The lithium metal composite electrode material provided by this invention fills the voids of a lithium-containing conductive layer, which serves as a supporting framework, with lithium metal particles. This lithium-containing conductive layer contains inorganic lithium compounds and lithium alloys. The lithium-containing conductive layer, acting as a three-dimensional supporting framework structure, encapsulates the lithium metal particles, thereby isolating them from the electrolyte and reducing irreversible reactions between the lithium metal and the electrolyte.

[0024] The lithium-containing conductive layer coating the surface of lithium metal particles can regulate the electron and ion conduction mechanism in lithium metal composite electrode materials, as well as the physical and chemical environment at the lithium metal interface. This effectively reduces the surface activity of the lithium metal active phase and provides sufficient space and active sites for lithium metal deposition, thereby suppressing the formation of lithium dendrites and changes in electrode volume, and improving the cycle stability and safety of the battery.

[0025] The lithium metal composite electrode material provided by this invention can significantly improve the cycle stability and safety of lithium metal secondary batteries.

[0026] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit the invention. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the structure of a lithium metal composite electrode material according to one embodiment of the present invention;

[0029] Figure 2 (a) shows the lithium-lithium symmetric battery in Example 1 of the present invention at 1 mA / cm². 2 Current density, 4mAh / cm 2 Cyclic curves under areal capacity conditions;

[0030] (b) The lithium-lithium symmetric battery in Example 1 of the present invention at 2mA / cm2 Current density, 4 mAh / cm 2 Cycle curve under surface capacity condition;

[0031] Figure 3 Cycle curve of constant current charge-discharge of lithium metal full cell in Example 1 and Comparative Example 1;

[0032] Figure 4 (a) is a lithium-lithium symmetric cell in Example 2 of the present application at 1 mA / cm 2 Current density, 1 mAh / cm 2 Cycle curve under surface capacity condition;

[0033] (b) is a lithium-lithium symmetric cell in Example 2 of the present application at 2 mA / cm 2 Current density, 2 mAh / cm 2 Cycle curve under surface capacity condition;

[0034] Figure 5 Cycle curve of constant current charge-discharge of lithium-lithium symmetric cell in Example 3 of the present application at 1 mA / cm 2 Current density and 1 mAh / cm 2 Cycle curve under surface capacity condition;

[0035] Figure 6 Cycle curve of constant current charge-discharge of lithium-lithium symmetric cell in Example 4 of the present application at 1 mA / cm 2 Current density and 1 mAh / cm 2 Capacity-voltage curve under surface capacity condition;

[0036] Figure 7 (a) is a lithium-lithium symmetric cell in Example 5 of the present application at 1 mA / cm 2 Current density, 1 mAh / cm 2 Cycle curve under surface capacity condition;

[0037] (b) is a lithium-lithium symmetric cell in Example 5 of the present application at 2 mA / cm 2 Current density, 2 mAh / cm 2 Cycle curve under surface capacity condition;

[0038] Figure 8 Cycle curve of constant current charge-discharge of lithium metal full cell in Example 6 and Comparative Example 2;

[0039] Figure 9 Structure diagram of lithium metal battery of one embodiment of the present application;

[0040] Figure 10 Structure diagram of battery module of one embodiment of the present application;

[0041] Figure 11 Structure diagram of a battery pack according to an embodiment of the present application;

[0042] Figure 12 Structure diagram of a device using a lithium metal battery as a power source according to an embodiment of the present application.

[0043] Legend: 1 - lithium metal particles; 2 - lithium-containing conductive layer; 3 - lithium metal battery; 4 - battery module; 5 - battery pack; 6 - electric vehicle.

[0044] The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate embodiments consistent with the present application and, together with the description, further serve to explain the principles of the application. DETAILED DESCRIPTION

[0045] The embodiments of the present application will be described in detail below with examples, but those skilled in the art will appreciate that the following examples are used only to illustrate the present application and should not be construed as limiting the scope of the present application. The specific conditions not mentioned in the examples are carried out according to the conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used are not specified by the manufacturer, and are all conventional products that can be purchased on the market.

[0046] It should be noted that: in the present application, all the embodiments and preferred embodiments mentioned in the present application can be combined to form new technical solutions unless otherwise specified. In the present application, all the technical features and preferred features mentioned in the present application can be combined to form new technical solutions unless otherwise specified. In the present application, unless otherwise specified, the percentage (%) or part refers to the percentage by weight or weight of the composition. In the present application, unless otherwise specified, each component or its preferred component can be combined to form a new technical solution. In the present application, unless otherwise specified, the numerical range "a~b" represents a shorthand representation of any real number combination between a and b, where a and b are real numbers. For example, the numerical range "6~22" represents that all real numbers between "6~22" have been listed in this article, and "6~22" is only a shorthand representation of these numerical combinations. The lower limit and upper limit of the range disclosed in the present application can be one or more lower limits and one or more upper limits, respectively. In the present application, unless otherwise specified, each reaction or operation step can be carried out sequentially or according to the sequence. Preferably, the reaction method in this article is carried out sequentially.

[0047] Unless otherwise specified, the professional and scientific terms used in this article have the same meaning as those familiar to those skilled in the art. In addition, any method or material similar or equivalent to the described content can also be applied in the present application.

[0048] In one aspect, the present application provides a lithium metal composite electrode material for a lithium metal battery, an embodiment of which has a structure as shown in Figure 1 comprising:

[0049] lithium metal particles 1 filled in a support framework, and a lithium-containing conductive layer 2 as the support framework, wherein the lithium-containing conductive layer 2 comprises an inorganic lithium compound and a lithium alloy.

[0050] In the present application, the inorganic lithium compound refers to an inorganic compound containing lithium. The inorganic lithium compound can form a structure-stable lithium ion-conducting framework material, thereby realizing the transmission of lithium ions. Meanwhile, the lithium alloy in the present application refers to an alloy containing lithium and at least one other metal. The lithium alloy can form an electron-ion conductive structure, providing more active sites for the deposition of lithium ions.

[0051] The lithium metal composite electrode material provided by the present application has the lithium metal particles encapsulated in the three-dimensional support framework structure of the lithium-containing conductive layer, thereby isolating the lithium metal particles from the electrolyte and reducing the irreversible reaction between the lithium metal and the electrolyte. Meanwhile, filling the lithium metal particles in the three-dimensional support framework structure can also inhibit the volume expansion of the lithium metal and effectively avoid the growth of lithium dendrites.

[0052] In the lithium metal composite electrode material of the present application, the lithium-containing conductive layer has strong lithium ion transmission performance, thereby improving the reaction speed of the electrode. In addition, the lithium-containing conductive layer has strong lithium affinity. After the dissolution of lithium ions, the porous support framework structure is left. In the process of lithium ion deposition, lithium ions are preferentially deposited in the pores of the support framework structure rather than on the surface of the support framework. Therefore, the dissolution and deposition processes of lithium ions do not cause changes in the thickness direction of the electrode, thereby improving the stability of the electrode structure.

[0053] The lithium metal composite electrode material provided by the present application can significantly improve the cycle stability and safety of lithium metal secondary batteries.

[0054] In some embodiments, the lithium-containing conductive layer is grown in situ on the surface of the lithium metal particles. That is, the surface of the lithium metal particles has a lithium-containing conductive layer as a support framework grown in situ thereon.

[0055] It should be noted that in situ growth refers to growing a lithium-containing conductive layer containing an inorganic lithium compound and a lithium alloy directly on the surface of the lithium metal particles. The in situ grown lithium-containing conductive layer has strong bonding force with the lithium metal particles, and the inorganic lithium compound itself has strong structural stability. Therefore, the lithium metal composite electrode material can significantly improve the stability of the structure and effectively inhibit the volume change of the lithium metal particles.

[0056] In some further embodiments, the inorganic lithium compound comprises at least one of lithium nitride, lithium sulfide, or lithium phosphide.

[0057] Lithium nitride, lithium sulfide, or lithium phosphide has high ionic conductivity, which can significantly provide the reaction speed of the lithium metal composite electrode material.

[0058] In some further embodiments, the inorganic lithium compound comprises at least one of lithium nitride, lithium sulfide, or lithium phosphide.

[0059] In some further embodiments, the metal in the lithium alloy comprises at least one of Zn, Mg, Ag, Al, Ge, Sn, Sb, In, or Ga.

[0060] By selecting the above-mentioned metal to form a lithium alloy, the lithiumophilic property of the three-dimensional support skeleton structure can be further improved. After the lithium in the lithium alloy is dissolved out, a porous structure of an electronic-ion hybrid transmission mechanism can be formed, so that the lithium ions are more likely to be deposited in the voids of the support skeleton rather than the surface of the support skeleton during lithium ion deposition, thereby reducing the volume change generated during the lithium ion solvent-deposition process.

[0061] In some further embodiments, the mass ratio of the lithium-containing conductive layer in the lithium metal composite electrode material is 10% to 20%.

[0062] By limiting the proportion of the lithium-containing conductive layer in the entire lithium metal composite electrode material, the electrical performance of the lithium metal composite electrode material can be further optimized, so that the lithium metal composite electrode material has both high specific capacity and high cycle stability.

[0063] In some further embodiments, the mass ratio of the lithium-containing conductive layer in the lithium metal composite electrode material is 10% to 20%.

[0064] In some embodiments of the present application, the lithium-containing conductive layer contains conductive carbon.

[0065] The addition of conductive carbon can not only improve the electronic conductivity, but also help to improve the mechanical strength of the lithium metal composite electrode material after tabletting.

[0066] In some further embodiments, the mass ratio of the lithium-containing conductive layer in the lithium metal composite electrode material is 10% to 20%.

[0067] In some further embodiments, the mass ratio of the lithium-containing conductive layer in the lithium metal composite electrode material is 10% to 20%.

[0068] By optimizing the mass ratio of conductive carbon in the lithium metal composite electrode material, the conductivity of the lithium metal composite electrode material can be improved, and the lithium-containing conductive layer serving as a support framework structure has strong structural stability.

[0069] It should be noted that, based on the mass of the lithium metal composite electrode material, the mass ratio of the conductive carbon is lower than the mass ratio of the inorganic lithium compound or the sum of the mass ratios of the inorganic lithium compound and the lithium alloy, and the mass ratio difference is controlled within 5% to 15%.

[0070] In some further embodiments, the particle size of the lithium metal particles is 1 μm to 50 μm, preferably 10 μm to 50 μm, and further preferably 15 μm to 40 μm. The particle size of the lithium metal particles is, for example, not limited to greater than or equal to 1 μm, greater than or equal to 5 μm, or greater than or equal to 10 μm, and less than or equal to 50 μm, less than or equal to 45 μm, or less than or equal to 40 μm.

[0071] By limiting the size of the lithium metal particles, the uniformity of the lithium-containing conductive layer grown in situ on the surface of the lithium metal particles can be improved.

[0072] In a second aspect, the present application provides a preparation method of a lithium metal composite electrode material for a lithium metal battery, comprising the following steps:

[0073] The lithium metal particles are filled into the lithium-containing conductive layer serving as a support framework to obtain the lithium metal composite electrode material; wherein the lithium-containing conductive layer comprises inorganic lithium compounds and lithium alloys.

[0074] In the present application, the lithium-containing conductive layer serves as a support framework structure, and the lithium metal particles are filled into the lithium-containing conductive layer.

[0075] The lithium metal composite electrode material obtained by the preparation method of the present application has all the advantages of the lithium metal composite electrode material provided in the first aspect of the present application, which will not be repeated here.

[0076] In some preferred embodiments, the lithium-containing conductive layer serving as a support framework is grown in situ on the surface of the lithium metal particles to obtain the lithium metal composite electrode material;

[0077] The lithium-containing conductive layer formed comprises inorganic lithium compounds and lithium alloys.

[0078] In-situ growth refers to growing a lithium-containing conductive layer containing inorganic lithium compounds and lithium alloy directly on the surface of lithium metal particles. The in-situ grown lithium-containing conductive layer has strong binding force with the lithium metal particles, and the inorganic lithium compounds themselves have strong structural stability, thus can significantly improve the structural stability of the lithium metal composite electrode material and effectively inhibit the volume change of the lithium metal particles.

[0079] In some embodiments, the lithium metal particles are contacted with the metal compound capable of reacting with lithium under solvent-free and oxygen-free conditions, and the lithium-containing conductive layer is grown in-situ on the surface of the lithium metal particles after reaction.

[0080] In this embodiment, the preparation method is carried out in a solvent-free and oxygen-free environment because lithium has strong chemical activity. The solvent includes water, organic solvents and the like. In the preparation method, the lithium metal particles are contacted with the metal compound capable of reacting with lithium under dry conditions, for example, dry mixing or the like. Through the contact, the lithium metal particles react with the metal in the metal compound, for example, undergo displacement reaction, so as to grow the lithium-containing conductive layer in-situ on the surface of the lithium metal particles.

[0081] In some embodiments, the lithium metal particles are mixed and ground with the metal compound under solvent-free and oxygen-free conditions, and then heat-treated to grow the lithium-containing conductive layer in-situ on the surface of the lithium metal particles. Generally, a passivation film is formed on the surface of the lithium metal particles, and the lithium metal can fully react with the metal compound through heating.

[0082] Further, the metal compound is an inorganic metal compound. The inorganic metal compound includes at least one of metal nitride, metal sulfide or metal phosphide, and preferably contains at least metal nitride. Lithium nitride, lithium sulfide or lithium phosphide formed after the reaction of the metal nitride, the metal sulfide or the metal phosphide with the lithium metal particles has good lithium ion conductivity, and especially, lithium nitride has higher lithium ion conductivity.

[0083] Further, the metal in the metal compound is selected from at least one of Zn, Ag, Al, Ge, Sn, Sb, In or Ga, and preferably contains at least aluminum.

[0084] In the preparation method of this embodiment, taking aluminum nitride as an example, because lithium metal has strong reducing property, the lithium element on the surface of the lithium metal particles contacts with the aluminum nitride and undergoes displacement reaction after heating, so as to reduce the trivalent aluminum atom to aluminum element and produce lithium nitride at the same time; the generated aluminum element further reacts with the lithium metal to generate lithium-aluminum alloy. The generated lithium nitride and lithium-aluminum alloy are distributed on the surface of the lithium metal particles.

[0085] In some embodiments of the present application, the mass of the metal compound accounts for 20% to 50% of the percentage content of the total mass of the lithium metal particles and the metal compound. By optimizing the amount of metal compound added, the percentage of the generated lithium-containing conductive layer in the lithium metal composite electrode material can be effectively controlled, thereby further optimizing the electrical performance of the lithium metal composite electrode material, enabling the lithium metal composite electrode material to have both high specific capacity and high cycle stability.

[0086] In some embodiments of the present application, the mass of the metal compound accounts for 20% to 50% of the percentage content of the total mass of the lithium metal particles and the metal compound. By optimizing the amount of metal compound added, the percentage of the generated lithium-containing conductive layer in the lithium metal composite electrode material can be effectively controlled, thereby further optimizing the electrical performance of the lithium metal composite electrode material, enabling the lithium metal composite electrode material to have both high specific capacity and high cycle stability.

[0087] In some embodiments of the present application, the mass of the metal compound accounts for 20% to 50% of the percentage content of the total mass of the lithium metal particles and the metal compound. By optimizing the amount of metal compound added, the percentage of the generated lithium-containing conductive layer in the lithium metal composite electrode material can be effectively controlled, thereby further optimizing the electrical performance of the lithium metal composite electrode material, enabling the lithium metal composite electrode material to have both high specific capacity and high cycle stability.

[0088] In some embodiments of the present application, the mass of the metal compound accounts for 20% to 50% of the percentage content of the total mass of the lithium metal particles and the metal compound. By optimizing the amount of metal compound added, the percentage of the generated lithium-containing conductive layer in the lithium metal composite electrode material can be effectively controlled, thereby further optimizing the electrical performance of the lithium metal composite electrode material, enabling the lithium metal composite electrode material to have both high specific capacity and high cycle stability.

[0089] In some embodiments of the present application, the mass of the metal compound accounts for 20% to 50% of the percentage content of the total mass of the lithium metal particles and the metal compound. By optimizing the amount of metal compound added, the percentage of the generated lithium-containing conductive layer in the lithium metal composite electrode material can be effectively controlled, thereby further optimizing the electrical performance of the lithium metal composite electrode material, enabling the lithium metal composite electrode material to have both high specific capacity and high cycle stability.

[0090] In some embodiments of the present application, the mass of the metal compound accounts for 20% to 50% of the percentage content of the total mass of the lithium metal particles and the metal compound. By optimizing the amount of metal compound added, the percentage of the generated lithium-containing conductive layer in the lithium metal composite electrode material can be effectively controlled, thereby further optimizing the electrical performance of the lithium metal composite electrode material, enabling the lithium metal composite electrode material to have both high specific capacity and high cycle stability.

[0091] In some embodiments of the present application, the mass of the metal compound accounts for 20% to 50% of the percentage content of the total mass of the lithium metal particles and the metal compound. By optimizing the amount of metal compound added, the percentage of the generated lithium-containing conductive layer in the lithium metal composite electrode material can be effectively controlled, thereby further optimizing the electrical performance of the lithium metal composite electrode material, enabling the lithium metal composite electrode material to have both high specific capacity and high cycle stability.

[0092] In some embodiments of the present application, the mass of the metal compound accounts for 20% to 50% of the percentage content of the total mass of the lithium metal particles and the metal compound. By optimizing the amount of metal compound added, the percentage of the generated lithium-containing conductive layer in the lithium metal composite electrode material can be effectively controlled, thereby further optimizing the electrical performance of the lithium metal composite electrode material, enabling the lithium metal composite electrode material to have both high specific capacity and high cycle stability.

[0093] The lithium metal composite electrode material prepared by the preparation method has a unique three-dimensional framework structure. During the mixing, grinding and heating of raw materials, lithium metal reacts in situ with nitride or sulfide or phosphide and other framework materials to form lithium alloy and lithium ion conductive materials as a three-dimensional support framework structure. Unreacted lithium metal particles are filled in the framework. The inorganic lithium compounds and lithium alloy in the framework structure have strong lithium affinity, and the lithium alloy has stronger lithium affinity. During the charge and discharge cycle of the battery, the lithium metal dissolves to leave a porous structure of electron-ion mixed conductive framework, and the lithium metal is preferentially deposited in the pores of the framework when it is deposited. The generated lithium nitride, lithium sulfide or lithium phosphide has high ion conductivity, thereby significantly improving the electrode reaction speed. On the other hand, the addition of conductive carbon such as carbon nanotubes or graphene can improve the electronic conductivity, facilitate the tabletting of the electrode, and improve the mechanical strength of the formed electrode. The lithium metal composite electrode prepared by the method suppresses the volume effect of lithium metal and the generation of lithium dendrites, reduces the consumption of electrolyte, and significantly improves the cycle stability of the electrode.

[0094] In some embodiments of the present application, the mixed and ground raw materials can be subjected to tabletting treatment before heat treatment. After tabletting treatment, the displacement reaction of lithium and other metals is facilitated. The pressure used in tabletting treatment can be, for example, 1-6 MPa, and is further preferably 3-4 MPa.

[0095] In a third aspect, the present application provides a lithium metal composite electrode for a lithium metal battery, which comprises the lithium metal composite electrode material of the first aspect of the present application or the lithium metal composite electrode material obtained by the preparation method of the second aspect of the present application.

[0096] The lithium metal composite electrode material of the present application or the lithium metal composite electrode material obtained by the preparation method of the present application is subjected to tabletting to obtain the lithium metal composite electrode. If the lithium metal composite electrode material itself is subjected to tabletting during preparation, it can be directly used as a lithium metal composite electrode.

[0097] In a fourth aspect, the lithium metal battery of one embodiment provided by the present application comprises, as shown in the figure, the lithium metal composite electrode of the present application. Figure 9

[0098] Referring to Figure 9 , the lithium metal battery 3 can comprise, for example, a shell, an electrode assembly, a top cover assembly and an electrolyte.

[0099] The cycle stability of the lithium metal composite electrode prepared by the method in a lithium-lithium symmetric battery is greatly improved. Compared with ordinary lithium metal electrodes, the cycle stability and operation safety of lithium metal secondary batteries with the lithium metal composite electrode as the negative electrode are greatly improved. ​

[0100] In a fifth aspect, the present application provides a battery module of an embodiment, as shown in Figure 10 comprising the lithium metal battery of the fourth aspect of the present application.

[0101] Referring to Figure 10 , the battery module 4 comprises a plurality of lithium metal batteries 3. The plurality of lithium metal batteries 3 are arranged in a longitudinal direction. The battery module 4 can be used as a power source or an energy storage device. The number of lithium metal batteries 3 in the battery module 4 can be adjusted according to the application and capacity of the battery module 4.

[0102] In a sixth aspect, the present application provides a battery pack of an embodiment, comprising the battery module of the fifth aspect of the present application.

[0103] Referring to Figure 11 , the battery pack 5 comprises an upper case, a lower case and the battery module 4. The upper case and the lower case are assembled together and form a space for accommodating the battery module 4. The battery module 4 is placed in the space of the assembled upper case and lower case. The output pole of the battery module 4 is led out from one or both of the upper case and the lower case to supply power to the outside or charge from the outside. The number and arrangement of the battery module 4 used in the battery pack 1 can be determined according to actual needs. The battery pack 1 can be used as a power source or an energy storage device.

[0104] In a seventh aspect, the present application provides a device of an embodiment, as shown in Figure 12 using the lithium metal battery as a power source, comprising the battery pack of the sixth aspect of the present application.

[0105] Referring to Figure 12 , the device is an electric vehicle 6. Of course, it is not limited to this, the device can be any electric vehicle (such as electric bus, electric tram, electric bicycle, electric motorcycle, electric scooter, electric golf cart, electric truck) other than electric vehicle, electric ship, electric tool, electronic equipment and energy storage system. The electric vehicle can be electric pure electric vehicle, hybrid electric vehicle, plug-in hybrid electric vehicle. Of course, according to the actual use form, the device provided by the seventh aspect of the present application can comprise the battery module 4 of the fifth aspect of the present application, of course, the device provided by the seventh aspect of the present application can also comprise the battery pack 5 of the sixth aspect of the present application.

[0106] The battery module, the battery pack and the device of the present application comprise the lithium metal battery of the present application, and thus at least have the same advantages as the lithium metal battery.

[0107] The lithium metal composite electrode material of the present application will be further described in detail below in combination with examples and comparative examples.

[0108] Example 1

[0109] The lithium metal composite electrode material in the embodiment uses aluminum nitride, lithium metal powder and carbon nanotube as raw materials, and the preparation method comprises the following steps:

[0110] Step S1) In anhydrous and oxygen-free environment, aluminum nitride (particle size 1-2 μm) is mixed and ground uniformly with lithium metal powder (particle size 10-50 μm), wherein the mass ratio of the raw materials is 1:2 of aluminum nitride to lithium metal powder;

[0111] Step S2) In anhydrous and oxygen-free environment, 10% (calculated based on the weight of all the added raw materials) of carbon nanotube is added to the mixture obtained in step S1) and mixed uniformly, and then a certain amount of the mixture is weighed and laid flat in a tablet press mold, and a tablet-shaped electrode with a diameter of 11 mm is pressed under a pressure of 3 MPa;

[0112] Step S3) In anhydrous and oxygen-free environment, the pressed tablet-shaped electrode is heat treated at 150°C for 2 hours to obtain a lithium metal composite electrode.

[0113] The prepared lithium metal composite electrode is used to assemble lithium-lithium symmetric battery and full battery, wherein the full battery is a lithium metal battery assembled with the lithium metal composite electrode in the embodiment as the negative electrode and lithium iron phosphate as the positive electrode. The electrolyte is a mixed solution of 1M lithium hexafluorophosphate (LiPF6) in ethylene carbonate, dimethyl carbonate and fluoroethylene carbonate (EC, DMC, FEC volume ratio is 45:45:10).

[0114] Comparative Example 1

[0115] The difference between the full battery in the present comparative example and Example 1 is that the negative electrode used in the present comparative example is a lithium metal sheet, and the positive electrode is also a lithium iron phosphate positive electrode, which has the same specific composition as in Example 1.

[0116] The lithium-lithium symmetric battery prepared in Example 1 has a cycle performance under the condition of 1 mA / cm 2 , 4 mAh / cm 2 , as shown in the figure, and the polarization voltage is stabilized at about 40 mV after 1000 hours. 2 The lithium-lithium symmetric battery prepared in Example 1 has a cycle performance under the condition of 2 mA / cm 2 , 4 mAh / cm 2 , as shown in the figure, and the polarization voltage is stabilized at about 70 mV after 600 hours. Figure 2 Figure 2

[0117] The full battery in Example 1 with the lithium metal composite electrode as the negative electrode and the lithium iron phosphate with a loading of 8 mg / cm 2 as the positive electrode has a constant current charge-discharge cycle curve under the condition of 2C rate as shown in Figure 3As shown, after 500 cycles, the capacity retention rate was 95%, and no short circuit occurred. In contrast, Comparative Example 1 used a common lithium metal sheet as the negative electrode with a loading of 8 mg / cm³. 2 Using lithium iron phosphate as the positive electrode, the constant current charge-discharge cycle curves under the same conditions are as follows: Figure 3 As shown, the battery short-circuited after 175 cycles.

[0118] Example 2

[0119] A lithium metal composite electrode was prepared using nano-aluminum nitride, lithium metal powder, and graphene as raw materials. The steps are as follows:

[0120] Step S1) In an anhydrous and oxygen-free environment, aluminum nitride (particle size 1-2 μm) and lithium metal powder (particle size 10-50 μm) are mixed and ground evenly, wherein the mass ratio of the raw materials is 1:2 of aluminum nitride to lithium metal powder.

[0121] Step S2) In an anhydrous and oxygen-free environment, add 5% (calculated based on the weight of all added raw materials) of graphene to the mixture obtained in step S1) and mix evenly. Then weigh a certain amount of the mixture, spread it flat in a tablet mold, and press it into a sheet electrode under a pressure of 3MPa.

[0122] Step S3) In an anhydrous and oxygen-free environment, the pressed sheet electrode is heat-treated at 150°C for 2 hours to obtain a lithium metal composite electrode.

[0123] Lithium-lithium symmetric cells and full cells were assembled using the fabricated lithium metal composite electrode. The full cell used the lithium metal composite electrode from this embodiment as the negative electrode and lithium iron phosphate as the positive electrode to form a lithium metal battery. The positive electrode was the same as that in Example 1, with a lithium iron phosphate loading of 8 mg / cm³. 2 The electrolyte is a mixed solution of 1M lithium hexafluorophosphate (LiPF6) in ethylene carbonate, dimethyl carbonate, and fluoroethylene carbonate (EC, DMC, FEC in a volume ratio of 45:45:10).

[0124] The cycle curve of the lithium-lithium symmetric battery prepared in this embodiment is as follows: Figure 4 As shown, at 1mA / cm 2 Current density, 1mAh / cm 2 Under the condition of areal capacitance, the polarization voltage is approximately 15mV; at 2mA / cm 2 Current density, 1mAh / cm 2 Under the given areal capacitance condition, the polarization voltage is approximately 40 mV. From Figure 4 As can be seen, the battery has good cycle reversibility.

[0125] Example 3

[0126] A lithium metal composite electrode was prepared using aluminum sulfide, lithium metal powder, and carbon nanotubes as raw materials. The steps are as follows:

[0127] Step S1) In an anhydrous and oxygen-free environment, aluminum sulfide (particle size 1-2 μm) and lithium metal powder (particle size 10-50 μm) are mixed and ground evenly, wherein the mass ratio of the raw materials is 1:3 of aluminum sulfide to lithium metal powder.

[0128] Step S2) In an anhydrous and oxygen-free environment, add 10% (calculated based on the weight of all added raw materials) of carbon nanotubes to the mixture obtained in step S1) and mix evenly. Then weigh a certain amount of the mixture and spread it flat in a tablet mold, and press it into a sheet electrode under a pressure of 4MPa.

[0129] Step S3) In an anhydrous and oxygen-free environment, the pressed sheet electrode is heat-treated at 120°C for 2 hours to obtain a lithium metal composite negative electrode.

[0130] Lithium-lithium symmetric cells and full cells were assembled using the fabricated lithium metal composite electrode. The full cell used the lithium metal composite electrode from this embodiment as the negative electrode and lithium iron phosphate as the positive electrode to form a lithium metal battery. The positive electrode was the same as that in Example 1, with a lithium iron phosphate loading of 8 mg / cm³. 2 The electrolyte is a mixed solution of 1M lithium hexafluorophosphate (LiPF6) in ethylene carbonate, dimethyl carbonate, and fluoroethylene carbonate (EC, DMC, FEC in a volume ratio of 45:45:10).

[0131] The lithium-lithium symmetric battery fabricated in this embodiment achieves a speed of 1 mA / cm². 2 Current density, 1mAh / cm 2 Cyclic performance under areal capacity conditions, such as Figure 5 As shown, after 200 hours, the polarization voltage stabilized at around 50mV.

[0132] Example 4

[0133] A lithium metal composite electrode was prepared using gallium phosphide, lithium metal powder, and carbon nanotubes as raw materials. The steps are as follows:

[0134] Step S1) In an anhydrous and oxygen-free environment, gallium phosphide (particle size 1-2 μm) and lithium metal powder (particle size 10-50 μm) are mixed and ground evenly, wherein the mass ratio of the raw materials is gallium phosphide:lithium metal powder 1:2.

[0135] Step S2) In an anhydrous and oxygen-free environment, add 10% (calculated based on the weight of all added raw materials) of carbon nanotubes to the mixture obtained in step S1) and mix evenly. Then weigh a certain amount of the mixture and spread it flat in a tablet mold, and press it into a sheet electrode under a pressure of 3MPa.

[0136] Step S3) In an anhydrous and oxygen-free environment, the pressed sheet electrode is heat-treated at 150°C for 2 hours to obtain a lithium metal composite electrode.

[0137] Lithium-lithium symmetric cells and full cells were assembled using the fabricated lithium metal composite electrode. The full cell used the lithium metal composite electrode from this embodiment as the negative electrode and lithium iron phosphate as the positive electrode to form a lithium metal battery. The positive electrode was the same as that in Example 1, with a lithium iron phosphate loading of 8 mg / cm³. 2 The electrolyte is a mixed solution of 1M lithium hexafluorophosphate (LiPF6) in ethylene carbonate, dimethyl carbonate, and fluoroethylene carbonate (EC, DMC, FEC in a volume ratio of 45:45:10).

[0138] The polarization voltage of the lithium-lithium symmetric battery fabricated in this embodiment is as follows: Figure 6 As shown, at 1mA / cm 2 Current density, 1mAh / cm 2 Under the condition of areal capacity, the polarization voltage is about 42mV, and the cycle reversibility is good.

[0139] Example 5

[0140] A lithium metal composite electrode was prepared using aluminum nitride, aluminum sulfide, lithium metal powder, and carbon nanotubes as raw materials. The steps are as follows:

[0141] Step S1) In an anhydrous and oxygen-free environment, aluminum nitride (particle size 1-2 μm), aluminum sulfide (particle size 1-2 μm) and lithium metal powder (particle size 10-50 μm) are mixed and ground evenly, wherein the mass ratio of each raw material is aluminum nitride: aluminum sulfide: lithium powder of 0.5:0.5:3.

[0142] Step S2) In an anhydrous and oxygen-free environment, 10% carbon nanotubes are added to the mixture obtained in step S1) and mixed evenly. Then, a certain amount of the mixture is weighed and spread evenly in a tablet mold and pressed into a sheet electrode under a pressure of 3MPa.

[0143] Step S3) In an anhydrous and oxygen-free environment, the pressed sheet electrode is heat-treated at 120°C for 2 hours to obtain a lithium metal composite electrode.

[0144] Lithium-lithium symmetric cells and full cells were assembled using the fabricated lithium metal composite electrode. The full cell used the lithium metal composite electrode from this embodiment as the negative electrode and lithium iron phosphate as the positive electrode to form a lithium metal battery. The positive electrode was the same as that in Example 1, with a lithium iron phosphate loading of 8 mg / cm³. 2 The electrolyte is a mixed solution of 1M lithium hexafluorophosphate (LiPF6) in ethylene carbonate, dimethyl carbonate, and fluoroethylene carbonate (EC, DMC, FEC in a volume ratio of 45:45:10).

[0145] The polarization voltage of the lithium-lithium symmetric battery prepared in the embodiment is shown in Fig. 1. The polarization voltage is about 25 mV at a current density of 1 mA / cm 2 , a capacity of 1 mAh / cm 2 , and a surface capacity of 1 mAh / cm 2 . The polarization voltage is about 50 mV at a current density of 2 mA / cm 2 , a capacity of 1 mAh / cm 2 , and a surface capacity of 1 mAh / cm 2 .

[0146] Example 6

[0147] The lithium metal composite electrode was prepared using nano-aluminum nitride, lithium metal powder and carbon nanotubes as raw materials, and the steps were as follows:

[0148] Step S1) In anhydrous and anaerobic environment, aluminum nitride (particle size 1-2 μm) and lithium metal powder (particle size 10-50 μm) were mixed and ground uniformly, wherein the mass ratio of the raw materials was aluminum nitride: lithium metal powder 1:2.

[0149] Step S2) In anhydrous and anaerobic environment, 10% (calculated based on the weight of all added raw materials) of carbon nanotubes were added to the mixture obtained in step S1) and mixed uniformly.

[0150] Step S3) In anhydrous and anaerobic environment, a certain amount of the mixture was weighed and the pressed sheet electrode was heat treated at 150°C for 2 hours to obtain a lithium metal composite electrode material.

[0151] Step S4) The sheet electrode with a diameter of 11 mm was pressed under a pressure of 3 MPa to obtain a lithium metal composite electrode.

[0152] The lithium metal full battery was prepared using the prepared lithium metal composite electrode, wherein the lithium metal full battery used the lithium metal composite electrode in the embodiment as the negative electrode and lithium iron phosphate as the positive electrode to assemble the lithium metal battery. The positive electrode was the same as that in Example 1, and the loading of lithium iron phosphate in the positive electrode was 8 mg / cm 2 . The electrolyte was a mixed solution of 1M lithium hexafluorophosphate (LiPF6) in ethylene carbonate, dimethyl carbonate and fluoroethylene carbonate (EC, DMC, FEC volume ratio 45:45:10).

[0153] Example 7

[0154] The lithium metal composite electrode was prepared using nano-aluminum nitride, lithium metal powder and graphene as raw materials, and the steps were as follows:

[0155] Step S1) mixing and grinding aluminum nitride (particle size 1-2 μm) and lithium metal powder (particle size 10-50 μm) uniformly in a waterless and oxygenless environment, wherein the mass ratio of raw materials is aluminum nitride: lithium metal powder = 1:1.5;

[0156] Step S2) adding 5% (calculated based on the weight of all added raw materials) graphene to the mixture obtained in step S1) and mixing uniformly in a waterless and oxygenless environment, then weighing a certain amount of the mixture, laying it flat in a tablet press mold, and pressing it into a sheet-shaped electrode under a pressure of 4 MPa;

[0157] Step S3) heat treating the pressed sheet-shaped electrode at 150°C for 2 hours in a waterless and oxygenless environment to obtain a lithium metal composite electrode.

[0158] A lithium metal full battery was prepared using the prepared lithium metal composite electrode, wherein the lithium metal full battery used the lithium metal composite electrode in this embodiment as the negative electrode and lithium iron phosphate as the positive electrode to assemble a lithium metal battery. The positive electrode was the same as that in Example 1, and the loading of lithium iron phosphate in the positive electrode was 8 mg / cm 2 The electrolyte was a mixed solution of 1M lithium hexafluorophosphate (LiPF6) in ethylene carbonate, dimethyl carbonate, and fluoroethylene carbonate (EC, DMC, FEC in a volume ratio of 45:45:10).

[0159] Example 8

[0160] A lithium metal composite electrode was prepared using nano-aluminum nitride, lithium metal powder, and graphene as raw materials, and the steps were as follows:

[0161] Step S1) mixing and grinding aluminum nitride (particle size 1-2 μm) and lithium metal powder (particle size 10-50 μm) uniformly in a waterless and oxygenless environment, wherein the mass ratio of raw materials is aluminum nitride: lithium metal powder = 1:1;

[0162] Step S2) adding 5% (calculated based on the weight of all added raw materials) graphene to the mixture obtained in step S1) and mixing uniformly in a waterless and oxygenless environment, then weighing a certain amount of the mixture, laying it flat in a tablet press mold, and pressing it into a sheet-shaped electrode under a pressure of 4 MPa;

[0163] Step S3) heat treating the pressed sheet-shaped electrode at 150°C for 2 hours in a waterless and oxygenless environment to obtain a lithium metal composite electrode.

[0164] A lithium metal full battery was prepared using the prepared lithium metal composite electrode, wherein the lithium metal full battery used the lithium metal composite electrode in this embodiment as the negative electrode and lithium iron phosphate as the positive electrode to assemble a lithium metal battery. The positive electrode was the same as that in Example 1, and the loading of lithium iron phosphate in the positive electrode was 8 mg / cm 2The electrolyte is a mixed solution of ethylene carbonate, dimethyl carbonate, and fluoroethylene carbonate (EC, DMC, FEC in a volume ratio of 45:45:10) with 1M lithium hexafluorophosphate (LiPF6).

[0165] Example 9

[0166] The lithium metal composite electrode is prepared using nano-aluminum nitride, lithium metal powder, and graphene as raw materials, and the steps are as follows:

[0167] Step S1) In anhydrous and oxygen-free environment, aluminum nitride (particle size 1-2 μm) and lithium metal powder (particle size 5-20 μm) are mixed and ground uniformly, wherein the mass ratio of raw materials is aluminum nitride: lithium metal powder = 1:2;

[0168] Step S2) In anhydrous and oxygen-free environment, 5% (calculated based on the weight of all added raw materials) of graphene is added to the mixture obtained in step S1) and mixed uniformly, then a certain amount of the mixture is weighed and laid flat in a tablet press mold, and a sheet-shaped electrode is pressed under a pressure of 3 MPa;

[0169] Step S3) In anhydrous and oxygen-free environment, the pressed sheet-shaped electrode is heat treated at 150°C for 2 hours to obtain a lithium metal composite electrode.

[0170] The lithium metal full battery is assembled using the prepared lithium metal composite electrode as the negative electrode and lithium iron phosphate as the positive electrode. The positive electrode is the same as in Example 1, and the loading of lithium iron phosphate in the positive electrode is 8 mg / cm 2 The electrolyte is a mixed solution of ethylene carbonate, dimethyl carbonate, and fluoroethylene carbonate (EC, DMC, FEC in a volume ratio of 45:45:10) with 1M lithium hexafluorophosphate (LiPF6).

[0171] Example 10

[0172] The lithium metal composite electrode is prepared using nano-aluminum nitride, lithium metal powder, and graphene as raw materials, and the steps are as follows:

[0173] Step S1) In anhydrous and oxygen-free environment, aluminum nitride (particle size 1-2 μm) and lithium metal powder (particle size 10-50 μm) are mixed and ground uniformly, wherein the mass ratio of raw materials is aluminum nitride: lithium metal powder = 1:2;

[0174] Step S2) In anhydrous and oxygen-free environment, 5% (calculated based on the weight of all added raw materials) of graphene is added to the mixture obtained in step S1) and mixed uniformly, then a certain amount of the mixture is weighed and laid flat in a tablet press mold, and a sheet-shaped electrode is pressed under a pressure of 3 MPa;

[0175] Step S3) heat-treating the pressed sheet electrode at 150°C for 2 hours in a waterless and oxygen-free environment to obtain a lithium metal composite electrode.

[0176] A lithium metal full cell was assembled using the prepared lithium metal composite electrode as the negative electrode and lithium iron phosphate as the positive electrode. The positive electrode was the same as that in Example 1, and the loading of lithium iron phosphate in the positive electrode was 8 mg / cm2. 2 The electrolyte was a mixed solution of 1 M lithium hexafluorophosphate (LiPF6) in ethylene carbonate, dimethyl carbonate and fluoroethylene carbonate (EC, DMC and FEC in a volume ratio of 45:45:10).

[0177] Example 11

[0178] A lithium metal composite electrode was prepared using nano-tin sulfide, zinc phosphide, lithium metal powder and graphene as raw materials, and the steps were as follows:

[0179] Step S1) In a waterless and oxygen-free environment, aluminum nitride (particle size 1-2 μm) was mixed and ground uniformly with lithium metal powder (particle size 10-50 μm), and the mass ratio of the raw materials was 0.5:0.5:3 of silver nitride:magnesium sulfide:lithium powder.

[0180] Step S2) In a waterless and oxygen-free environment, 5% (calculated based on the weight of all the added raw materials) of graphene was added to the mixture obtained in step S1) and mixed uniformly, and then a certain amount of the mixture was weighed and laid flat in a tablet press mold, and a sheet electrode was pressed under a pressure of 3 MPa.

[0181] Step S3) In a waterless and oxygen-free environment, the pressed sheet electrode was heat-treated at 150°C for 2 hours to obtain a lithium metal composite electrode.

[0182] A lithium metal full cell was assembled using the prepared lithium metal composite electrode as the negative electrode and lithium iron phosphate as the positive electrode. The positive electrode was the same as that in Example 1, and the loading of lithium iron phosphate in the positive electrode was 8 mg / cm2. 2 The electrolyte was a mixed solution of 1 M lithium hexafluorophosphate (LiPF6) in ethylene carbonate, dimethyl carbonate and fluoroethylene carbonate (EC, DMC and FEC in a volume ratio of 45:45:10).

[0183] The full cells in Examples 1-11 and the full cell in Comparative Example 1 were subjected to constant current charge and discharge tests at a rate of 2C, and the cycle numbers at which the capacities were 98%, 95%, 90%, 85% and short circuit occurred, respectively, were recorded. The test results are shown in Table 1.

[0184] Table 1

[0185]

[0186] Example 12

[0187] A lithium metal composite electrode was prepared using aluminum nitride, lithium metal powder and carbon nanotube as raw materials, and the steps were as follows:

[0188] Step S1) In anhydrous and oxygen-free environment, aluminum nitride (particle size 1-2 μm) was mixed and ground uniformly with lithium metal powder (particle size 10-50 μm), wherein the mass ratio of raw materials was aluminum nitride: lithium metal powder 1:2;

[0189] Step S2) In anhydrous and oxygen-free environment, 10% (calculated based on the weight of all added raw materials) of carbon nanotubes were added to the mixture obtained in step S1) and mixed uniformly, and then a certain amount of the mixture was weighed and laid flat in a tablet press mold, and a tablet electrode with a diameter of 11 mm was pressed under a pressure of 4 MPa;

[0190] Step S3) In anhydrous and oxygen-free environment, the pressed tablet electrode was heat treated at 150°C for 2 hours to obtain a lithium metal composite electrode.

[0191] The prepared lithium metal composite electrode was used as the negative electrode, and a sulfurized polyacrylonitrile with a loading of 2 mg / cm 2 was used as the positive electrode to assemble a lithium metal battery. The electrolyte was a mixed solution of 1M lithium hexafluorophosphate (LiPF6) in ethylene carbonate, dimethyl carbonate, fluoroethylene carbonate (EC, DMC, FEC volume ratio 45:45:10).

[0192] Comparative Example 2

[0193] The negative electrode in this comparative example used a common lithium metal sheet as the negative electrode, and the other components were the same as those of the full battery in Example 12. That is, a lithium metal battery with a common lithium metal sheet as the negative electrode and a sulfurized polyacrylonitrile with a loading of 2 mg / cm 2 as the positive electrode. The electrolyte was a mixed solution of 1M lithium hexafluorophosphate (LiPF6) in ethylene carbonate, dimethyl carbonate, fluoroethylene carbonate (EC, DMC, FEC volume ratio 45:45:10).

[0194] The constant current charge-discharge cycle curve of the full battery in Example 12 with a lithium metal composite electrode as the negative electrode and a sulfurized polyacrylonitrile with a loading of 2 mg / cm 2 as the positive electrode at 1C rate is shown in Figure 8 . After 600 cycles, the capacity retention rate was 98%, and no short circuit occurred.

[0195] In Comparative Example 2, a common lithium metal sheet was used as the negative electrode, and a sulfurized polyacrylonitrile with a loading of 2 mg / cm 2The sulfidized polyacrylonitrile is a positive electrode, and a constant current charge-discharge cycle curve under the same condition is as shown in Figure 8 After 360 cycles, the capacity retention rate is 58%.

[0196] In summary, the present application provides a lithium metal composite electrode material and a preparation method thereof, a lithium metal composite electrode, and a lithium metal battery made of the lithium metal electrode. The lithium metal composite negative electrode material prepared by the present application has a unique three-dimensional skeleton structure, and lithium metal particles are filled in the skeleton. The skeleton structure has a lithium affinity property. The skeleton left after the dissolution of lithium metal is a porous structure and is an electronic-ion mixed conductor. When lithium metal is deposited, it can be preferentially deposited in the pores of the skeleton. The lithium metal composite electrode material prepared by the method suppresses the volume effect of lithium metal and the generation of lithium dendrites, and reduces the consumption of electrolyte. The cycle stability of the lithium metal composite electrode prepared by the method is greatly improved in a lithium-lithium symmetric battery. Compared with ordinary lithium metal electrodes, the cycle stability of lithium metal secondary batteries with the lithium metal composite electrode as the negative electrode is greatly improved. The preparation method of the lithium metal composite electrode material provided in the present application is simple to operate and easy to realize industrial application.

[0197] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A lithium metal composite electrode material for a lithium metal battery, characterized in that, Comprise: lithium metal particles and a lithium-containing conductive layer as a support framework, the lithium metal particles being filled in the support framework; the lithium-containing conductive layer comprises an inorganic lithium compound, conductive carbon and a lithium alloy, the particle size of the lithium metal particles is 1-50 μm; the mass ratio of the conductive carbon in the lithium metal composite electrode material is 5-15%; the mass ratio of the lithium-containing conductive layer in the lithium metal composite electrode material is 10-20%.

2. The lithium metal composite electrode material of claim 1, wherein, The lithium-containing conductive layer is in-situ grown on the surface of the lithium metal particles.

3. The lithium metal composite electrode material of claim 1, wherein, The inorganic lithium compound comprises at least one of lithium nitride, lithium sulfide or lithium phosphide.

4. The lithium metal composite electrode material of any one of claims 1-3, wherein, The metal in the lithium alloy is selected from at least one of Zn, Mg, Ag, Al, Ge, Sn, Sb, In or Ga.

5. The lithium metal composite electrode material of any one of claims 1-3, wherein, The conductive carbon comprises at least one of carbon nanotubes, carbon fibers or graphene.

6. A method of preparing a lithium metal composite electrode material for a lithium metal battery as claimed in any one of claims 1-5, characterized in that, Comprise the following steps: filling lithium metal particles in a lithium-containing conductive layer as a support framework to obtain the lithium metal composite electrode material, wherein the lithium-containing conductive layer comprises an inorganic lithium compound and a lithium alloy.

7. The production method according to claim 6, characterized by, Comprise the following steps: in-situ growing a lithium-containing conductive layer as a support framework on the surface of lithium metal particles to obtain the lithium metal composite electrode material.

8. The preparation method according to claim 7, characterized in that, The filling of the lithium metal particles in the lithium-containing conductive layer as a support framework to obtain the lithium metal composite electrode material comprises: under solvent-free and oxygen-free conditions, contacting the lithium metal particles with a metal compound capable of reacting with lithium, and after the reaction, in-situ growing the lithium-containing conductive layer on the surface of the lithium metal particles.

9. The preparation method according to claim 8, characterized in that, The contacting of the lithium metal particles with the metal compound capable of reacting with lithium under solvent-free and oxygen-free conditions, and after the reaction, in-situ growing the lithium-containing conductive layer on the surface of the lithium metal particles comprises: under solvent-free and oxygen-free conditions, mixing and grinding the lithium metal particles with the metal compound, and then heat treating to in-situ grow the lithium-containing conductive layer on the surface of the lithium metal particles.

10. The production method according to claim 8 or 9, characterized by, The mass percentage of the metal compound in the total mass of the lithium metal particles and the metal compound is 20-50%.

11. The production method according to claim 8 or 9, characterized by, The metal compound is an inorganic metal compound.

12. The method of claim 11, wherein, The inorganic metal compound comprises at least one of metal nitride, metal sulfide or metal phosphide.

13. The preparation method according to claim 11, characterized in that, The inorganic metal compound at least contains metal nitride.

14. The production method according to claim 8 or 9, characterized by, The metal in the metal compound is selected from at least one of Zn, Ag, Al, Ge, Sn, Sb, In or Ga.

15. The production method according to claim 8 or 9, characterized by, The metal in the metal compound at least contains aluminum.

16. The production method according to claim 8 or 9, characterized by, The particle size of the metal compound is 50 nm-2 μm, and the particle size of the lithium metal particles is at least 2 times larger than the particle size of the metal compound.

17. The production method according to claim 8 or 9, characterized by, The particle size of the lithium metal particles is more than 5 times larger than the particle size of the metal compound.

18. The production method according to claim 8 or 9, characterized by, The contacting of the lithium metal particles with the metal compound capable of reacting with lithium under solvent-free and oxygen-free conditions, and after the reaction, in-situ growing the lithium-containing conductive layer on the surface of the lithium metal particles comprises: first mixing and grinding the lithium metal particles with the metal compound, then adding and grinding conductive carbon, and then heat treating to in-situ grow the lithium-containing conductive layer on the surface of the lithium metal particles.

19. The method of claim 18, wherein, The method comprises first tabletting and then heat treating after mixing and grinding the lithium metal particles with the metal compound and then mixing and grinding with conductive carbon.

20. The method of claim 9, wherein, The heat treatment temperature in the heat treatment is 100-300℃, and the heat treatment time is 1-2h.

21. The method of claim 20, wherein, When the metal compound at least contains aluminum nitride, the heat treatment temperature is 150-200℃.

22. A lithium metal composite electrode for a lithium metal battery, characterized in that, The lithium metal composite electrode material of any one of claims 1-5 or obtained by the preparation method of any one of claims 6-21.

23. A lithium metal battery, characterized in that, The lithium metal composite electrode of claim 22.

24. A battery module, comprising: The lithium metal battery of claim 23.

25. A battery pack, characterized by, The battery module of claim 24.

26. An apparatus using a lithium metal battery as a power source, characterized by, The battery pack of claim 25.

27. The apparatus of claim 26, wherein, The device comprises an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, an electric truck, an electric ship, an energy storage system.

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