Solid or semi-solid battery structures to prevent lithium dendrite formation

Abstract

The present invention provides a solid or semi-solid battery structure to prevent the formation of lithium dendrites. [Solution] The solid or semi-solid battery structure comprises a negative electrode 10, a positive electrode 20, and a dielectric thin film 30 located between the positive and negative electrodes. The battery structure further includes a metal interface layer 40 to prevent the formation of lithium dendrites on the surface of the negative electrode. The metal interface layer comprises a lithium-activated metal 48 and a non-lithium-activated metal 49. The lithium-activated metal can form an alloy with lithium ions in the battery, and the alloy does not grow in the direction of the positive electrode, forming a non-crystalline sheet layer deposited near the negative electrode, thereby preventing lithium ions from being reduced to lithium metal and transformed into lithium dendrites when they are present at the negative electrode. The non-lithium-activated metal does not interact with lithium ions, enhances mechanical strength, and maintains stability.

Description

[Technical Field]

[0001] This invention relates to a battery structure, and more specifically, to a solid or semi-solid battery structure for preventing the formation of lithium dendrites. [Background technology]

[0002] Conventional solid or semi-solid battery structures consist of a negative electrode, a positive electrode, and a dielectric thin film located between the positive and negative electrodes. During the charging and discharging process, electrons are transmitted via an external circuit, and transmission within the battery occurs as lithium ions moving through the dielectric layer. When charged, lithium stored in the positive electrode is propagated to the negative electrode in the form of lithium ions through the dielectric thin film, and is stored in a manner in which lithium metal is deposited or a compound with a negative electrode active material is formed. [Overview of the project] [Problems that the invention aims to solve]

[0003] However, the lithium metal deposition method presented significant challenges. Because the potential of the negative electrode of the compound is close to the reduction potential of lithium ions, lithium ions in the electrolyte may acquire electrons from the negative electrode site under the aforementioned conditions, leading to the deposition of lithium metal on its surface. The lithium metal is deposited along a specific direction, and as the amount of deposited lithium increases, the lithium metal forms dendrites. Since dendrites are elongated like needles, there was a safety issue because the battery could short-circuit when they penetrate the dielectric thin film. On the other hand, during the continuous charging and discharging process, dendrites are prone to rupture, and when they rupture, they become covered with insulating reduction products of the electrolyte, resulting in dead lithium. These lithium metals do not undergo electrochemical reactions, which meant a loss of final capacity and a reduction in battery life. Therefore, if the deposition of lithium metal could be designed to be controlled, the safety and lifespan of the battery would be greatly improved.

[0004] Therefore, after careful consideration, the creators of this invention discovered that the above objective could be achieved by adopting a solid or semi-solid battery structure that prevents the formation of lithium dendrites, and thus completed this invention.

[0005] This invention has been made in view of the above-mentioned conventional problems. To solve the above problems, the main objective of this invention is to provide a solid or semi-solid battery structure that prevents the formation of lithium dendrites.

[0006] In other words, by applying the structure according to the present invention, when the battery is charged, even if lithium ions reach the negative electrode, they do not directly acquire electrons emitted from the negative electrode and become lithium metal. Instead, an alloy capable of temporarily storing lithium ions is formed together with the lithium active metal in the metal interface layer. Furthermore, this alloy is amorphous, and its growth direction does not grow in the direction of the positive electrode like lithium dendrites. A non-crystalline sheet layer is formed near the negative electrode, preventing the alloy from communicating with the positive and negative electrodes. Therefore, even if a battery with the structure according to the present invention is used for a long period of time, the entire dielectric thin film will not be penetrated and short-circuited by the accumulated lithium dendrites. The battery's durability and stability are maintained while its performance is improved. [Means for solving the problem]

[0007] To achieve the above objective, a solid or semi-solid battery structure for preventing the formation of lithium dendrites, which is one aspect of the present invention, comprises a negative electrode, a positive electrode, and a dielectric thin film located between the positive electrode and the negative electrode. The battery structure further includes a metal interface layer used to prevent the formation of lithium dendrites on the anode surface when the battery is charged. The dielectric thin film is attached to one side of the metal interface layer, and the negative electrode is attached to the other side of the metal interface layer, so that lithium ions on the negative electrode side are not directly bonded to electrons so that lithium dendrites are not formed. The metal interface layer comprises a lithium-active metal and a non-lithium-active metal. The lithium-active metal can form an alloy with lithium ions in the battery, so that when lithium ions are present at the negative electrode, they can be reduced to lithium metal and transformed into lithium dendrites. The non-lithium-active metal does not interact with lithium ions, enhances mechanical strength, and maintains stability. The alloy formed by the lithium-activated metal and lithium ions does not grow in the direction of the positive electrode, and a non-crystalline sheet layer is formed near the negative electrode.

[0008] The following information will become clear from the description in the specification and drawings described later. [Brief explanation of the drawing]

[0009] [Figure 1] This is a partially enlarged view showing a solid or semi-solid battery structure for preventing the formation of lithium dendrites according to one embodiment of the present invention. [Figure 2] This is a schematic diagram showing a solid or semi-solid battery structure for preventing the formation of lithium dendrites according to one embodiment of the present invention. [Figure 3] This is a schematic diagram showing an example of lithium dendrite formation according to the present invention. [Figure 4] This is a schematic diagram showing the negative electrode structure according to the present invention. [Modes for carrying out the invention]

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the following embodiments and can take various forms as long as it belongs to the technical scope of the present invention.

[0011] First, an embodiment of a battery structure including a ceramic oxide thin film and a metal interface layer 40 of the present invention will be described in detail with reference to FIGS. 1 to 4.

[0012] A general solid or semi-solid battery structure includes a negative electrode 10, a positive electrode 20, and a dielectric thin film 30 (i.e., the ceramic sulfide thin film) positioned between the positive electrode 20 and the negative electrode 10.

[0013] The battery structure further includes the metal interface layer 40 to prevent a situation where lithium dendrites (dendrite) 100 are generated on the surface of the anode (when charging, the negative electrode becomes the anode) when the battery is charged. The dielectric thin film 30 is adhered to one side of the metal interface layer 40, and the negative electrode 10 is adhered to the other side of the metal interface layer 40.

[0014] FIG. 3 shows a state where the metal interface layer 40 is not adhered to a conventional battery. When the metal interface layer 40 is absent, as the end of battery charging approaches, the voltage of the negative electrode 10 decreases. Therefore, when lithium ions move to the negative electrode 10, some lithium ions directly acquire electrons deposited from the negative electrode 10, and lithium metal that becomes the lithium dendrite 100 is formed, and lithium ions no longer adhere to the electrode material. When used for a long time, the deposition of the lithium dendrite 100 increases. When it extends from the negative electrode 10 to the positive electrode 20, the entire dielectric thin film 30 is penetrated and short-circuited.

[0015] The thickness of the metal interface layer 40 ranges from 1 μm to 50 μm, and the metal interface layer 40 includes a lithium active metal 48 and a non-lithium active metal 49 (transition metal). The lithium active metal 48 refers to an element capable of forming an amorphous alloy with lithium, for example, at least one of the metal elements in Groups 3A - 5A of the periodic table such as silicon (Si), aluminum (Al), tin (Sn), zinc (Zn), silver (Ag), magnesium (Mg), etc. The non-lithium active metal 49 is, for example, at least one of the elements in Groups 3B - 8B of the periodic table. The lithium active metal 48 occupies a molar ratio of 5% - 50% of the metal interface layer 40, and the non-lithium active metal 49 occupies a molar ratio of ≥50% of the metal interface layer 40.

[0016] Since the lithium active metal 48 is capable of forming an alloy with lithium ions in the battery, it is possible to prevent the lithium ions in the negative electrode 10 from being reduced to lithium metal and changing into the lithium dendrite 100. As an advantage of forming an alloy, the lithium metal is in a reversible state, and since the electronegativity of the alloy is very low, it is easy to dissociate, thus it can temporarily store lithium ions. The advantage of adding the non-lithium active metal 49 is that since it does not act with lithium ions, it can strengthen the mechanical strength and maintain stability.

[0017] As the reason for selecting an element capable of forming an “amorphous” alloy with lithium ions as the lithium active metal 48, the growth direction of the amorphous alloy does not grow in the direction of the positive electrode 20 like the lithium dendrite 100, but a sheet layer without a crystalline state is formed and deposited near the negative electrode 10, so the situation where the alloy is connected to the positive electrode 20 and the negative electrode 10 does not occur.

[0018] The metal interface layer 40 is formed by vapor deposition, sputtering, or by forming it as an alloy and then adhering it between the negative electrode 10 and the dielectric thin film 30.

[0019] The positive electrode 20 is filled with a positive electrode slurry, which serves as a binder, and a plurality of positive electrode particles distributed within the positive electrode slurry. The positive electrode slurry and the positive electrode particles generate side reactions with passing lithium ions, thus consuming the available lithium ions.

[0020] The negative electrode 10 comprises a negative electrode substrate 11, which is a carrier board on which the material of the negative electrode 10 is placed, and a negative electrode slurry layer 12 that is applied to the negative electrode substrate 11 and which forms the negative electrode plate 13 as a whole. The negative electrode slurry layer 12 is composed of a negative electrode slurry 14.

[0021] The negative electrode slurry 14 comprises a plurality of negative electrode active material particles for storing or releasing lithium ions. The negative electrode active material particles include pure silicon (Si) material, pure lithium (Li) material, carbon material (the carbon material is selected from at least one of graphite, hard carbon, soft carbon, etc.), silicon-carbon composite material (Si-C), and silicon-oxygen-carbon composite material (SiO x -C) and others have been selected, at least one of which is selected.

[0022] The negative electrode slurry 14 further contains polymer materials (e.g., CMC (carboxymethyl cellulose)), conductive agents (e.g., carbon nanotubes), lithium salts (e.g., Li3PO4 (lithium phosphate)), etc. Since this is prior art, its explanation will not be repeated here.

[0023] The dielectric thin film 30 is a ceramic electrolyte sheet. The ceramic electrolyte sheet is composed of a plurality of ceramic electrolyte particles. The ceramic electrolyte particles have a lithium ion conductivity (lithium ion conductivity of 10 -5 cm 2At least one or a combination thereof is selected from ceramic oxides having a diffusion coefficient greater than / s, oxides having a garnet structure, oxides having a perovskite structure, and sulfides. The thickness of the ceramic electrolyte sheet is in the range of 30 μm to 200 μm. The ceramic oxide having lithium ion conductivity is, for example, lithium aluminum germanium phosphate (LAGP) and lithium aluminum titanium phosphate (LATP) having a NASICON (sodium (Na) superionic conductor) structure, and the oxide having a garnet structure is, for example, lithium lanthanum zirconium oxide (Li7La3Zr2O 12 The perovskite oxide is, for example, lithium lanthanum zirconium oxide (LLZO). The perovskite oxide is, for example, lithium lanthanum titanium oxide (LLTO), and the sulfide is, for example, LPSC (LPSCl, sulfide solid electrolyte), LGPS (Li 10 GeP2S 12 The material is Lithium germanium phosphorus sulfur, and the plurality of ceramic electrolyte particles are selected from at least one of the materials mentioned above.

[0024] When the ceramic electrolyte particles are composed of an LLZO material, the LLZO material is formed by selecting at least one from LLZO, Ga-LLZO (Ga-doped LLZO, gallium-doped lithium lanthanum zirconium oxide), Cu-LLZO (Cu-doped LLZO, copper-doped lithium lanthanum zirconium oxide), Ta-LLZO (Ta-doped LLZO, tantalum-doped lithium lanthanum zirconium oxide), Sr-LLZO (Sr-doped LLZO, strontium-doped lithium lanthanum zirconium oxide), and Al-LLZO (Al-doped LLZO, aluminum-doped lithium lanthanum zirconium oxide).

[0025] When the ceramic electrolyte particles are composed of LAGP, the LAGP is Li 1+x Al x Ge 2-x (PO4)3 or Li 1+x+y Al x Ge 2-x-y-z M y N z (PO4)3 is selected. When the ceramic electrolyte particles are composed of LATP, the LATP is Li 1+x Al x Ti 2-x (PO4)3, or Li 1+x+y Al x Ti 2-x-y-z M y N z (PO4)3 is selected. Here, x is in the range of 0.1 to 0.8, y is in the range of 0 to 0.2, and z is in the range of 0 to 0.2. M is Sc 3+ (scandium ion), Y 3+ (yttrium ion), Ga 3+ (gallium ion), In 3+ (indium ion), La 3+ (lanthanum ion), etc., which are trivalent cations, and N is Zr 4+ (zirconium ion), Si 4+ (silicon ion), Sn 4+These are tetravalent cations such as (tin ions).

[0026] An advantage of this invention is that, by applying the structure according to this invention, when the battery is charged, even if lithium ions reach the negative electrode, they do not directly acquire electrons emitted from the negative electrode and become lithium metal. Instead, an alloy capable of temporarily storing lithium ions is formed together with the lithium active metal in the metal interface layer. Furthermore, this alloy is amorphous, and its growth direction does not grow in the direction of the positive electrode like lithium dendrites. A non-crystalline sheet layer is formed near the negative electrode, preventing the alloy from communicating with the positive and negative electrodes. Therefore, even if a battery with the structure according to this invention is used for a long period of time, the entire dielectric thin film will not be penetrated and short-circuited by the accumulated lithium dendrites. Battery durability and stability are maintained while battery performance is improved.

[0027] The embodiments described above are provided to facilitate understanding of the present invention and are not intended to limit its interpretation. The present invention may be modified or improved without departing from its spirit, and it goes without saying that equivalents thereof are included. [Explanation of Symbols]

[0028] 10 negative electrode 11 Negative electrode substrate 12. Negative electrode slurry layer 13 Negative plate 14. Negative electrode slurry 20 positive electrode 30 Dielectric Thin Films 40 Metal interface layer 48 Lithium-activated metals 49 Non-lithium active metals 100 Lithium Dendrites

Claims

1. A solid or semi-solid battery structure for preventing the formation of lithium dendrites, the battery structure comprising a negative electrode, a positive electrode, and a dielectric thin film located between the positive electrode and the negative electrode, The aforementioned battery structure is A metal interface layer used to prevent the formation of lithium dendrites on the negative electrode surface when a battery is charged, wherein a dielectric thin film is attached to one side of the metal interface layer, the negative electrode is attached to the other side of the metal interface layer, and the lithium ions on the negative electrode side are not directly bonded to electrons in such a way as lithium dendrites are not formed, further comprising the metal interface layer. The metal interface layer comprises a lithium-activated metal and a non-lithium-activated metal. The lithium-activated metal can form an alloy with lithium ions in the battery, thereby preventing lithium ions from being reduced to lithium metal and transforming into lithium dendrites when present at the negative electrode. The non-lithium-activated metal does not interact with lithium ions, thereby enhancing mechanical strength and maintaining stability. A solid or semi-solid battery structure for preventing the formation of lithium dendrites, characterized in that the alloy formed by the lithium active metal and lithium ions does not grow in the direction of the positive electrode, and a non-crystalline sheet layer is deposited near the negative electrode, and the lithium active metal refers to an element capable of forming an amorphous alloy with lithium.

2. The solid or semi-solid battery structure for preventing the formation of lithium dendrites, as described in claim 1, characterized in that the element is at least one of the metallic elements of groups 3A to 5A in the periodic table.

3. The solid or semi-solid battery structure for preventing the formation of lithium dendrites, characterized in that the non-lithium active metal is at least one of the elements in groups 3B to 8B of the periodic table, as described in claim 1.

4. The negative electrode comprises a negative electrode substrate, which is a carrier board on which the material of the negative electrode is placed, and a negative electrode slurry layer coated on the negative electrode substrate, the entire layer of which forms a negative electrode plate, wherein the negative electrode slurry layer is composed of negative electrode slurry, and the negative electrode slurry is A solid or semi-solid battery structure for preventing the formation of lithium dendrites, as described in claim 1, comprising a plurality of negative electrode active material particles used for storing or releasing lithium ions, wherein the negative electrode active material particles are selected from at least one of pure silicon material, pure lithium material, carbon material, silicon-carbon composite material (Si-C), and silicon-oxygen-carbon composite material (SiOx-C), and the carbon material is selected from at least one of graphite, hard carbon, soft carbon, etc.

5. The dielectric thin film is a ceramic electrolyte sheet, and the ceramic electrolyte sheet is composed of a plurality of ceramic electrolyte particles, characterized in that this is a solid or semi-solid battery structure for preventing the formation of lithium dendrites as described in claim 1.

6. The aforementioned ceramic electrolyte particles have lithium ion conductivity (lithium ion conductivity is 10 －５ cm ２ A solid or semi-solid battery structure for preventing the formation of lithium dendrites, characterized in that at least one or a combination thereof is selected from among ceramic oxides having a diffusion coefficient greater than / s, oxides having a garnet structure, oxides having a perovskite structure, and sulfides.

7. The ceramic oxide having the lithium ion conduction ability is selected from lithium aluminum germanium phosphate (LAGP) having a NASICON (sodium (Na) super ionic conductor) structure and lithium aluminum titanium phosphate (LATP), and the oxide having the garnet structure is selected from lithium lanthanum zirconium oxide (Li ７ La ３ Zr ２ O １２ , lithium lanthanum zirconium oxide, LLZO), the oxide having the perovskite structure is selected from lithium lanthanum titanate (lithium lanthanum titanate, LLTO), and the sulfide is selected from LPSC (LPSCl, sulfide solid electrolyte) and LGPS (Li １０ GeP ２ S １２ , Lithium germanium phosphorus sulfur), and the plurality of ceramic electrolyte particles are characterized in that at least one of the above materials is selected. A solid or semi-solid battery structure for preventing the situation in which lithium dendrites are generated according to claim 6.

8. The solid or semi-solid battery structure for preventing the formation of lithium dendrites according to claim 5, characterized in that, when the ceramic electrolyte particles are composed of an LLZO material, the LLZO material is formed by selecting at least one from LLZO, Ga-LLZO, Cu-LLZO, Ta-LLZO, Sr-LLZO, and Al-LLZO.

9. If the ceramic electrolyte particles are composed of LAGP, then the LAGP is Li １＋ｘ Al ｘ Ge ２－ｘ (PO ４ ) ３ or Li １＋ｘ＋ｙ Al ｘ Ge ２－ｘ－ｙ－ｚ M ｙ N ｚ (PO ４ ) ３ Selected from, if the ceramic electrolyte particles are composed of LATP, then the LATP is Li １＋ｘ Al ｘ Ti ２－ｘ (PO ４ ) ３ or Li １＋ｘ＋ｙ Al ｘ Ti ２－ｘ－ｙ－ｚ M ｙ N ｚ (PO ４ ) ３ A solid or semi-solid battery structure for preventing the formation of lithium dendrites according to claim 5, characterized in that it is selected from, where x is in the range of 0.1 to 0.8, y is in the range of 0 to 0.2, z is in the range of 0 to 0.2, M is a trivalent cation, and N is a tetravalent cation.

10. The aforementioned trivalent cation is Sc ３＋ (Scandium ion), Y ３＋ (Yttrium ion), Ga ３＋ (Gallium ion), In ３＋ (Indium ions), La ３＋ (Lanthanum ion, etc.) are selected, and the tetravalent cation is Zr ４＋ (Zirconium ion), Si ４＋ (Silicon ions), Sn ４＋ A solid or semi-solid battery structure for preventing the formation of lithium dendrites as described in 9, characterized in that it is selected from (tin ions), etc.

11. The solid or semi-solid battery structure for preventing the formation of lithium dendrites, as described in claim 1, characterized in that the thickness of the metal interface layer is in the range of 1 μm to 50 μm.

12. The solid or semi-solid battery structure for preventing the formation of lithium dendrites, as described in claim 1, characterized in that the lithium active metal accounts for 5% to 50% of the molar ratio of the metal interface layer, and the non-lithium active metal accounts for ≥50% of the molar ratio of the metal interface layer.

13. The solid or semi-solid battery structure for preventing the formation of lithium dendrites, as described in claim 5, characterized in that the thickness of the ceramic electrolyte sheet is in the range of 30 μm to 200 μm.

Images