Lithium metal battery and electric device

Abstract

The application provides a lithium metal battery and an electric device. The lithium metal battery comprises a positive electrode sheet, a negative electrode sheet, and a lithium inhibition layer arranged on the negative electrode sheet close to the positive electrode sheet side, the lithium inhibition layer is arranged at the edge of the negative electrode sheet, the positive electrode sheet comprises a positive electrode current collector and a positive electrode film layer arranged on at least one side of the positive electrode current collector, and a boundary line of the orthographic projection of the positive electrode film layer on the negative electrode sheet falls within the range surrounded by the outer peripheral line of the orthographic projection of the lithium inhibition layer on the negative electrode sheet.

Description

Technical Field

[0001] This application relates to the field of solid-state battery technology, and in particular to a lithium metal battery and an electrical device thereof. Background Technology

[0002] With the continuous development of society and the economy, portable devices, electric vehicles, and long-range energy storage devices require rechargeable batteries with long cycle life and high energy density. Lithium-ion batteries have profoundly changed daily life; however, the energy density of lithium-ion batteries is approaching 350 Wh·kg⁻¹. -1 The upper limit. Compared to lithium-ion batteries, lithium metal batteries can achieve a practical energy density exceeding 400 Wh·kg⁻¹. -1 This is due to the high specific capacity and low electrode potential of the lithium metal anode.

[0003] During the charging process of lithium metal batteries, lithium ions are released from the positive electrode active material and migrate to the negative electrode surface, where they are reduced to metallic lithium. In this process, lithium ions released from the positive electrode may extend and migrate towards the edge region of the negative electrode, where they may deposit. This deposition of lithium metal at the outer edge region causes a decrease in battery charging and discharging efficiency, an increase in resistance, electrode deformation, and a deterioration in battery life. In severe cases of lithium deposition, dendrites deposited at these edge regions can penetrate the electrolyte layer or separator layer and make localized contact with the positive electrode, forming a short circuit, leading to increased self-discharge or creating safety hazards.

[0004] The methods described in this section are not necessarily methods that had been previously conceived or adopted. Unless otherwise specified, no method described in this section should be assumed to be prior art simply because it is included in this section. Similarly, unless otherwise specified, the issues mentioned in this section should not be considered to be accepted in any prior art. Utility Model Content

[0005] This application is made in view of the above claims and its purpose is to provide a lithium metal battery and an electrical device.

[0006] The first aspect of this application provides a lithium metal battery, comprising: a negative electrode, a positive electrode, and a lithium suppression layer disposed on the negative electrode near the positive electrode, the lithium suppression layer being disposed at the edge of the negative electrode, the positive electrode including a positive current collector and a positive electrode film disposed on at least one side of the positive current collector, the boundary line of the orthographic projection of the positive electrode film onto the negative electrode surface falling within the area enclosed by the outer perimeter line of the orthographic projection of the lithium suppression layer onto the negative electrode.

[0007] The lithium metal battery provided in this application embodiment restricts the lithium metal deposited on the negative electrode to a range defined by the inner edge of the lithium suppression layer, thereby reducing the outward extension and precipitation of lithium metal at the edge of the negative electrode, reducing the probability of lithium dendrite growth, and extending the life of the lithium metal battery.

[0008] A second aspect of this application provides an electrical device comprising the lithium metal battery of the first aspect.

[0009] This power device combines high energy density with a long battery life. Attached Figure Description

[0010] Further details, features, and advantages of this disclosure are disclosed in the following description of exemplary embodiments in conjunction with the accompanying drawings, in which:

[0011] Figure 1 This is a schematic diagram of a lithium metal battery according to an exemplary embodiment;

[0012] Figure 2 This is a schematic diagram of a lithium metal battery according to another exemplary embodiment;

[0013] Figure 3 This is a schematic diagram of a negative electrode sheet according to an exemplary embodiment;

[0014] Figure 4 This is a schematic diagram of a negative electrode sheet according to another exemplary embodiment;

[0015] Figure 5 This is a schematic diagram of a negative electrode sheet according to another exemplary embodiment;

[0016] Figure 6 This is a schematic diagram of a negative electrode sheet according to another exemplary embodiment;

[0017] Figure 7 This is a schematic diagram of a negative electrode according to another exemplary embodiment. Detailed Implementation

[0018] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0020] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0021] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0022] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0023] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0024] It should be understood that in this specification, the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship or dimensions based on the orientation or positional relationship or dimensions shown in the accompanying drawings. These terms are used only for ease of description and are not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the scope of protection of this application.

[0025] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0026] Figure 1 This is a lithium metal battery according to an exemplary embodiment. For example... Figure 1 As shown, the lithium metal battery 1000 includes a negative electrode 100, a positive electrode 200, and a lithium suppression layer 300 disposed on the negative electrode 100 near the positive electrode 200. The lithium suppression layer 300 is disposed at the edge of the negative electrode 100. The positive electrode 200 includes a positive current collector 210 and a positive electrode film 220 disposed on at least one side of the positive current collector 210. The boundary line of the orthogonal projection of the positive electrode film 220 onto the surface of the negative electrode 100 falls within the area enclosed by the outer perimeter line of the orthogonal projection of the lithium suppression layer 300 onto the negative electrode 100.

[0027] In this application, a lithium metal battery refers to a secondary battery in which the negative electrode contains lithium metal. Lithium metal can be pure lithium or a lithium alloy formed by lithium and other metals, including but not limited to Al, Mg, K, Na, Ca, Sr, Ba, Si, Ge, Sb, Pb, Sn, In, and Zn. The lithium metal can be pre-deposited before the secondary battery is packaged, or it can be deposited on the negative electrode during the secondary battery's cycling process; this type of battery is also called a negative electrodeless battery.

[0028] In some implementations, the positive current collector includes, but is not limited to, materials such as aluminum, aluminum alloy, stainless steel, nickel, and titanium.

[0029] In some embodiments, the positive electrode film layer includes a positive electrode active material. The positive electrode active material includes, but is not limited to, layered active materials containing lithium, spinel-type active materials, olivine-type active materials, etc., and may specifically include one or more of lithium cobalt oxide, lithium nickel oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium manganese oxide, lithium iron phosphate, lithium manganese iron phosphate, etc.

[0030] The lithium metal battery provided in this application embodiment restricts the lithium metal deposited on the negative electrode to a range defined by the inner edge of the lithium suppression layer, thereby reducing the outward extension and precipitation of lithium metal at the edge of the negative electrode, reducing the probability of lithium dendrite growth, and extending the life of the lithium metal battery.

[0031] In some implementations, please refer to [the documentation / reference]. Figure 1 The boundary line of the positive electrode film layer 220 projected onto the surface of the negative electrode 100 falls within the area enclosed by the inner periphery line of the positive projection of the lithium suppressor layer 300 onto the negative electrode 100.

[0032] In some implementations, such as Figure 2 As shown, the boundary line of the positive electrode film layer 220 projected onto the surface of the negative electrode plate 100 falls within the range of the positive projection of the lithium suppression layer 300 onto the negative electrode plate 100.

[0033] Figure 3This is a negative electrode sheet according to an exemplary embodiment. For example... Figures 1-3 As shown, the negative electrode 100 includes a negative current collector 110 and a lithium metal layer 120 disposed on at least one side of the negative current collector 110, and a lithium suppression layer 300 disposed at the surface edge of the lithium metal layer 120.

[0034] In some implementations, please refer to [the documentation / reference]. Figure 2 The width L1 of the lithium plating layer 300 and the width L2 of the positive electrode film layer 220 are greater than or equal to the width L3 of the lithium metal layer 120.

[0035] The width direction refers to the direction perpendicular to the connection line between the electrode tab and the current collector. Please refer to [reference needed]. Figure 2 and Figure 3 The width LI of the lithium plating layer 300 refers to the total width of the lithium plating layer disposed on the surface of the lithium metal layer 120, which is the sum of LI' and L1".

[0036] In existing technologies, to ensure sufficient lithium insertion sites at the negative electrode after being extracted from the positive electrode and to reduce lithium deposition at the negative electrode, the width of the negative electrode film is often set to be greater than the width of the positive electrode film; the excess portion is called the overhang region. For lithium metal batteries, since lithium metal is used as the negative electrode active material, the overhang region still cannot reduce the growth and formation of lithium dendrites. Therefore, a lithium plating layer should be provided at least in the region where the negative electrode lithium metal layer extends beyond the positive electrode film, which can effectively reduce the probability of dendrite formation and improve the cycle life of lithium metal batteries.

[0037] It is understood that the lithium suppressor layer can be prepared using any method known in the art. Examples include, but are not limited to, one or more of the following: tape application, extrusion coating, gravure coating, inkjet printing, UV curing after coating, vacuum sputtering, and 3D printing.

[0038] Figure 4 This is a negative electrode sheet according to an exemplary embodiment. For example... Figure 4 As shown, the negative electrode 100 includes a negative current collector 110 and a lithium metal layer 120 disposed on at least one side of the negative current collector 110, and a lithium suppression layer 300 disposed on the end face of the lithium metal layer 120.

[0039] Figure 5 This is a negative electrode sheet according to an exemplary embodiment. For example... Figure 5 As shown, the negative electrode 100 includes a negative current collector 110 and a lithium metal layer 120 disposed on at least one side of the negative current collector 110. The lithium suppression layer 300 is disposed at the surface edge of the lithium metal layer 120 and the end face of the lithium metal layer 120.

[0040] Figure 6 This is a negative electrode sheet according to an exemplary embodiment. For example... Figure 6As shown, the negative electrode 100 includes a negative current collector 110, and a lithium suppression layer 130 is disposed on at least one side of the negative current collector 110.

[0041] In this embodiment, lithium metal is not pre-deposited on the negative electrode current collector, and the battery is a negative electrode-free battery. During charge and discharge cycles, lithium metal is deposited on the negative electrode current collector between the lithium suppression layers.

[0042] In some embodiments, the negative electrode current collector 110 includes one or more of copper, nickel, carbon-copper composite, carbon-nickel composite, stainless steel, and polymer composite current collectors. Furthermore, the shape of the negative electrode current collector can be, for example, foil, foam, mesh, or porous.

[0043] In some implementations, the thickness of the negative electrode current collector is 2µm-20µm, and can be selected as 3µm-10µm.

[0044] In some implementations, other functional layers are provided between the negative electrode current collector and the lithium metal layer, such as an intermediate layer that helps to uniformly deposit lithium.

[0045] In some embodiments, the lithium suppression layer includes a lithium-repellent material, wherein the lithium nucleation overpotential of the lithium-repellent material is greater than or equal to 40 mV, optionally greater than or equal to 60 mV, and further optionally greater than or equal to 100 mV.

[0046] In this application, lithophobic materials refer to materials on which lithium metal has a high nucleation overpotential. Nucleation overpotential represents the energy required for lithium nucleation and growth on the material. The higher the nucleation overpotential, the less likely lithium is to nucleate on the material, and thus the less likely lithium deposition will occur.

[0047] In this application, nucleation overpotential has a well-known meaning in the art, referring to the additional potential required to form a new phase or structure during an electrochemical process. Nucleation overpotential represents the energy required for lithium nucleation; the higher the nucleation overpotential, the less likely lithium is to nucleate on the material, and the less likely lithium deposition will occur on the material.

[0048] In some embodiments, the lithium-averse material comprises one or more of inorganic oxides and polymers, wherein the inorganic oxides include one or more of CuO, Fe3O4, Fe2O3, MnO, MnO2, and TiO2, and the polymers include one or more of polyimide, polyurea, polyamide (nylon 66), polyimide-amide, polyurethane, polythiourea, polyester, and polyethylene glycol.

[0049] In some embodiments, the lithium suppressor layer also includes one or more of a solid electrolyte and a lithium-containing electrolyte salt.

[0050] In some embodiments, the solid electrolyte includes one or more of sulfide electrolytes, oxide electrolytes, nitride electrolytes, and halide electrolytes.

[0051] In some embodiments, the oxide electrolyte includes one or more of lithium lanthanum zirconium oxide, lithium lanthanum zirconium tantalum oxide, lithium lanthanum zirconium aluminum oxide, lithium lanthanum zirconium gallium oxide, lithium lanthanum titanium oxide, lithium germanium aluminum phosphate, and lithium titanium aluminum phosphate.

[0052] In some embodiments, the lithium-containing electrolyte salt includes one or more of lithium perchlorate, lithium tetrafluoroborate, lithium hexafluorophosphate, and lithium difluorosulfonylimide.

[0053] In some embodiments, the lithium-containing electrolyte salt includes one or more of lithium perchlorate, lithium tetrafluoroborate, lithium hexafluorophosphate, and lithium difluorosulfonylimide.

[0054] In some embodiments, the thickness of the lithium suppression layer is 5nm-100um, optionally 10nm-60um, and further optionally 50nm-50um.

[0055] The lithium metal battery further includes an electrolyte disposed between the positive electrode and the negative electrode, wherein the electrolyte includes one or more of solid electrolyte, electrolyte solution or gel electrolyte.

[0056] Figure 7 This is a negative electrode sheet according to an exemplary embodiment. For example... Figure 7 As shown, the negative electrode 100 includes a negative current collector 110 and a lithium metal layer 120 disposed on at least one side of the negative current collector 110. A lithium suppression layer 300 is disposed at the surface edge of the lithium metal layer 120, and a protective layer 400 is disposed on the surface of the lithium metal layer 120.

[0057] During the charging and discharging process of lithium metal batteries, especially during charging, needle-shaped lithium crystals are easily deposited unevenly on the surface of the lithium metal layer 120, forming lithium dendrites. Once dendrites precipitate, the electronic conductivity of that area increases, leading to porosity of the lithium metal layer during repeated charging and discharging. This results in decreased interface smoothness and deterioration of battery performance. Applying a protective layer 400 to the surface of the lithium metal layer 120 can suppress uneven lithium deposition, reduce the probability of lithium dendrite formation, and improve the cycle life of the lithium metal battery.

[0058] In some embodiments, the lithium-ion conductivity of the protective layer is greater than or equal to 10. -3 mS / cm.

[0059] In some embodiments, the lithium-ion conductivity of the protective layer may be selected as 10. -3 mS / cm, 2×10 -3mS / cm, 3×10 -3 mS / cm, 4×10 -3 mS / cm, 5×10 -3 mS / cm, 6×10 -3 mS / cm, 7×10 -3 mS / cm, 8×10 -3 mS / cm, 9×10 -3 mS / cm, 10 -2 mS / cm or any value between the two. In some embodiments, the protective layer comprises one or more of copper nitride-polyacrylonitrile fibers, amorphous carbon, and metal nanoparticles.

[0060] In some embodiments, the protective layer comprises copper nitride-polyacrylonitrile fibers.

[0061] Copper nitride-polyacrylonitrile fiber possesses excellent ionic conductivity, electronic conductivity, electrochemical stability, and mechanical strength. It not only facilitates the uniform deposition of lithium on the negative electrode but also reduces the volume change of the lithium metal negative electrode during the charge and discharge process, suppresses lithium metal expansion, and further improves the cycle life of lithium metal batteries.

[0062] In a second aspect, this application provides an electrical device including a lithium metal battery of any embodiment.

[0063] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A lithium metal battery, characterized in that, include; A positive electrode, a negative electrode, and a lithium suppression layer disposed on the negative electrode near the positive electrode, wherein the lithium suppression layer is disposed at the edge of the negative electrode. The positive electrode includes a positive current collector and a positive electrode film layer disposed on at least one side of the positive current collector, wherein the boundary line of the positive electrode film layer in the thickness direction falls within the width range of the outer perimeter line of the lithium suppression layer in the thickness direction.

2. The lithium metal battery according to claim 1, characterized in that, The negative electrode includes a negative current collector and a lithium metal layer disposed on at least one side of the negative current collector. The lithium suppression layer is disposed at the surface edge of the lithium metal layer and / or the end face of the lithium metal layer.

3. The lithium metal battery according to claim 1, characterized in that, The negative electrode sheet includes a negative current collector, and the lithium suppression layer is disposed on at least one side of the negative current collector.

4. The lithium metal battery according to any one of claims 1 to 3, characterized in that, The boundary line of the positive electrode film layer in the thickness direction falls within the range of the lithium suppressor layer in the thickness direction.

5. The lithium metal battery according to any one of claims 1 to 3, characterized in that, The lithium suppression layer includes a lithium-repellent material, and the lithium nucleation overpotential of the lithium-repellent material is greater than or equal to 40mV.

6. The lithium metal battery according to any one of claims 1 to 3, characterized in that, The lithium suppression layer includes a lithium-repellent material, and the lithium nucleation overpotential of the lithium-repellent material is greater than or equal to 60mV.

7. The lithium metal battery according to any one of claims 1 to 3, characterized in that, The lithium suppression layer includes a lithium-repellent material, and the lithium nucleation overpotential of the lithium-repellent material is greater than or equal to 100mV.

8. The lithium metal battery according to any one of claims 1 to 3, characterized in that, The thickness of the lithium suppression layer is 5nm-100um.

9. The lithium metal battery according to any one of claims 1 to 3, characterized in that, The thickness of the lithium suppression layer is 10nm-60um.

10. The lithium metal battery according to any one of claims 1 to 3, characterized in that, The thickness of the lithium suppression layer is 50nm-50um.

11. The lithium metal battery according to claim 2, characterized in that, A protective layer is disposed on the surface of the lithium metal layer, and the lithium-ion conductivity of the protective layer is greater than or equal to 10. -3 mS / cm.

12. The lithium metal battery according to claim 3, characterized in that, The lithium metal battery is a negative electrode-less battery.

13. An electrical appliance, characterized in that, The lithium metal battery includes any one of claims 1 to 12.

Images