US-20260128364-A1 - ALL-SOLID-STATE BATTERY INCLUDING DOUBLE LAYER SOLID ELECTROLYTE AND METHOD FOR MANUFACTURING THE SAME

Abstract

Provided are an all-solid-state battery including a double layer solid electrolyte, which improves the robustness while suppressing a thermal runway phenomenon and exhibits an excellent electro-chemical characteristic, and a method for manufacturing the same. The all-solid-state battery includes a negative electrode, a first solid electrolyte layer positioned on the negative electrode, a second solid electrolyte layer disposed on the first solid electrolyte layer, and a positive electrode positioned on the second solid electrolyte layer. The first solid electrolyte layer includes an inorganic flame retardant, and the second solid electrolyte layer includes an endothermic flame retardant.

Inventors

• Min Sun KIM
• Yeo Min Yoon
• Yong Seok Choi
• Young Jin Nam

Assignees

• HYUNDAI MOTOR COMPANY
• KIA CORPORATION

Dates

Publication Date

20260507

Application Date

20250430

Priority Date

20241104

Claims (20)

1. 1 . An all-solid-state battery comprising: a negative electrode; a first solid electrolyte layer positioned on the negative electrode; a second solid electrolyte layer disposed on the first solid electrolyte layer; and a positive electrode positioned on the second solid electrolyte layer, wherein the first solid electrolyte layer includes an inorganic flame retardant, and wherein the second solid electrolyte layer includes an endothermic flame retardant.
2. 2 . The all-solid-state battery of claim 1 , wherein the inorganic flame retardant includes at least one selected from the group consisting of LLZO, LATP, SiO 2 , ZnO, SnO 2 , Mn 3 O 4 , Sn 2 P 2 O 7 , an aluminum oxide, a magnesium oxide, zeolite, a zirconium compound, a calcium salt, and a boron compound.
3. 3 . The all-solid-state battery of claim 1 , wherein the first solid electrolyte layer includes the inorganic flame retardant in an amount ranging from 20 wt % to 50 wt %, based on a weight of a solid electrolyte included in the first solid electrolyte layer.
4. 4 . The all-solid-state battery of claim 1 , wherein the endothermic flame retardant includes at least one selected from the group consisting of Mg(OH) 2 , Al(OH) 3 , Sb 2 O 3 , H 3 BO 3 , Fe(OH) 3 , CaCO 3 , Ca(OH) 2 , Zn(OH) 2 , NaOH, a calcium-magnesium hydroxide, hydrotalcite, bemate, talc, doconite, calcium sulfate hydrate, and magnesium sulfate hydrate.
5. 5 . The all-solid-state battery of claim 1 , wherein the second solid electrolyte layer includes the endothermic flame retardant in an amount ranging from 5 wt % to 20 wt %, based on a weight of a solid electrolyte included in the second solid electrolyte layer.
6. 6 . The all-solid-state battery of claim 1 , wherein a ratio between a thickness of the first solid electrolyte layer and a thickness of the second solid electrolyte layer ranges from 1:9 to 9:1.
7. 7 . The all-solid-state battery of claim 1 , wherein a sum of a thickness of the first solid electrolyte layer and a thickness of the second solid electrolyte layer ranges from 10 μm to 120 μm.
8. 8 . The all-solid-state battery of claim 1 , wherein each of the first solid electrolyte layer and the second solid electrolyte layer further includes a binder.
9. 9 . The all-solid-state battery of claim 8 , wherein the content of the binder ranges from 0.5 wt % to 5 wt %, based on a weight of a solid electrolyte in each of the first solid electrolyte layer and the second solid electrolyte layer.
10. 10 . The all-solid-state battery of claim 8 , wherein the binder includes at least one selected from the group consisting of polybutadiene rubber (BR), styrene-butadiene rubber (SBR), nitrile butadiene rubber (NBR), polyimide (PI), polyvinylidene fluoride (PVDF), and ethylene propylene diene monomer rubber (EPDM).
11. 11 . A method for manufacturing an all-solid-state battery, the method comprising: manufacturing the all-solid-state battery in which a negative electrode, a first solid electrolyte layer, a second solid electrolyte layer, and a positive electrode are sequentially stacked (S0), wherein the first solid electrolyte layer includes an inorganic flame retardant, and wherein the second solid electrolyte layer includes an endothermic flame retardant.
12. 12 . The method of claim 11 , wherein the manufacturing the all-solid-state battery include: manufacturing a negative electrode assembly by sequentially stacking the negative electrode, the first solid electrolyte layer, and the second solid electrolyte layer; and stacking the negative electrode assembly and the positive electrode such that the second solid electrolyte layer faces the positive electrode.
13. 13 . The method of claim 12 , wherein the negative electrode assembly is manufactured in a wet-on-wet or wet-on-dry scheme.
14. 14 . The method of claim 11 , wherein the manufacturing the all-solid-state battery includes: manufacturing a positive electrode assembly by sequentially stacking the positive electrode, the second solid electrolyte layer, and the first solid electrolyte layer; and stacking the positive electrode assembly and the negative electrode such that the first solid electrolyte layer faces the negative electrode.
15. 15 . The method of claim 14 , wherein the positive electrode assembly is manufactured in a wet-on-wet or wet-on-dry scheme.
16. 16 . The method of claim 11 , wherein the manufacturing the all-solid-state battery includes: manufacturing a negative electrode assembly including the negative electrode and the first solid electrolyte layer; manufacturing a positive electrode assembly including the positive electrode and the second solid electrolyte layer; and stacking the positive electrode assembly and the positive electrode assembly such that the first solid electrolyte layer and the second solid electrolyte layer face each other.
17. 17 . The method of claim 16 , wherein each of the negative electrode assembly or the positive electrode assembly is manufactured in a wet-on-wet or wet-on-dry scheme.
18. 18 . An all-solid-state battery comprising: a negative electrode; a first solid electrolyte layer positioned on the negative electrode; a second solid electrolyte layer disposed on the first solid electrolyte layer; and a positive electrode positioned on the second solid electrolyte layer, wherein the first solid electrolyte layer includes at least one component selected from the group consisting of LLZO, LATP, SiO 2 , ZnO, SnO 2 , Mn 3 O 4 , Sn 2 P 2 O 7 , an aluminum oxide, a magnesium oxide, zeolite, a zirconium compound, a calcium salt, and a boron compound, and wherein the second solid electrolyte layer includes at least one component selected from the group consisting of Mg(OH) 2 , Al(OH) 3 , Sb 2 O 3 , H 3 BO 3 , Fe(OH) 3 , CaCO 3 , Ca(OH) 2 , Zn(OH) 2 , NaOH, a calcium-magnesium hydroxide, hydrotalcite, bemate, talc, doconite, calcium sulfate hydrate, and magnesium sulfate hydrate.
19. 19 . The all-solid-state battery of claim 18 , wherein the at least one component included in the first solid electrolyte layer is in an amount ranging from 20 wt % to 50 wt %, based on a weight of a solid electrolyte included in the first solid electrolyte layer.
20. 20 . The all-solid-state battery of claim 18 , wherein the at least one component included in the second solid electrolyte layer is in an amount ranging from 5 wt % to 20 wt %, based on a weight of a solid electrolyte included in the second solid electrolyte layer.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application claims the benefit of priority to Korean Patent Application No. 10-2024-0154681, filed in the Korean Intellectual Property Office on Nov. 4, 2024, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD The present disclosure relates to an all-solid-state battery including a double layer solid electrolyte, capable of improving the robustness of an electrolyte layer while suppressing a thermal runway phenomenon and a method for manufacturing the same. BACKGROUND A lithium secondary battery has been extensively used in various fields such as an electric vehicle and a portable electronic device, but causes several safety issues. In particular, a positive electrode material having a higher content of nickel (Ni) has been mainly employed for the purpose of a higher energy density, which results in reducing the starting temperature of pyrolysis to increase calorific value, such that the risk of a thermal runway phenomenon is increased. In addition, a silicon (Si) negative electrode has been employed for the purpose of a higher theoretical capacity. The silicon negative electrode is severely expanded the in volume during charging/discharging process and causes the precipitation of lithium metal during the charging/discharging process for a longer term, which results in an internal short circuit of a battery such that the thermal runway phenomenon is caused. Accordingly, an all-solid-state battery has been significantly spotlighted as a next-generation energy storage device because of reducing the leakage of an electrolyte or the risk of flame by using a solid electrolyte, which is different from an existing lithium ion battery. However, the all-solid-state battery is not free in a safety issue such as the thermal runway phenomenon. In particular, the all-solid-state battery has a difficulty in maintaining both thermal stability and mechanical stability between the positive electrode and the negative electrode due to the characteristic of a multi-layer structure. Accordingly, there is required the development of the all-solid-state battery capable of maintaining the energy density and the performance while ensuring both the thermal stability and the mechanical stability. SUMMARY The present disclosure has been made to solve the above-mentioned problems occurring in the prior art while advantages achieved by the prior art are maintained intact. An aspect of the present disclosure relates to an all-solid-state battery including a double layer solid electrolyte, capable of improving the robustness of an electrolyte layer while suppressing a thermal runway phenomenon and a method for manufacturing the same. More specifically, the present disclosure is to improve the robustness of an electrolyte layer through a first solid electrolyte layer including an inorganic flame retardant, and to reduce a heating start temperature through a second solid electrolyte layer including an endothermic flame retardant such that a thermal runway phenomenon is suppressed. The technical problems to be solved by the present disclosure are not limited to the aforementioned problems, and any other technical problems not mentioned herein will be clearly understood from the following description by those skilled in the art to which the present disclosure pertains. According to an aspect of the present disclosure, there is provided an all-solid-state battery including a double layer solid electrolyte and a method for manufacturing the same. In more detail, (1) the present disclosure provides an all-solid-state battery including a negative electrode, a first solid electrolyte layer positioned on the negative electrode, a second solid electrolyte layer positioned on the first solid electrolyte layer, and a positive electrode positioned on the second solid electrolyte layer. The first solid electrolyte layer includes an inorganic flame retardant, and the second solid electrolyte layer includes an endothermic flame retardant. (2) The present disclosure provides an all-solid-state battery, in which the inorganic flame retardant includes at least one selected from the group consisting of LLZO, LATP, SiO2, ZnO, SnO2, Mn3O4, Sn2P2O7, an aluminum oxide, a magnesium oxide, zeolite, a zirconium compound, a calcium salt, and a boron compound, in (1). (3) The present disclosure provides an all-solid-state battery, in which the first solid electrolyte layer includes the inorganic flame retardant in an amount ranging from 20 wt % to 50 wt %, based on a weight of a solid electrolyte included in the first solid electrolyte layer, in (1) or (2). (4) The present disclosure provides an all-solid-state battery, in which the endothermic flame retardant includes at least one selected from the group consisting of Mg(OH)2, Al(OH)3, Sb2O3, H3BO3, Fe(OH)3, CaCO3, Ca(OH)2, Zn(OH)2, NaOH, a calcium-magnesium hydroxide, hydrotalcite, bemate, talc, doconite, calcium sulfate hydrate, and magnesi