Preparation method of interface modification layer based on coffee ring effect and solid-state battery

Abstract

The invention relates to a preparation method of an interface modification layer based on a coffee ring effect, the interface modification layer based on the coffee ring effect prepared by the preparation method and a solid-state battery, and the preparation method comprises the following steps: spraying a metal salt precursor solution on the surface of a high-temperature solid-state electrolyte; a plurality of annular structures are formed on the surface of the solid electrolyte, and the interface modification layer is prepared. According to the preparation method provided by the invention, the coffee ring effect is utilized, the metal salt precursor solution is rapidly evaporated and decomposed on the surface of the solid electrolyte, and a plurality of ring structures are formed on the surface of the solid electrolyte to prepare the interface cross-linking layer, so that the interface contact between the solid electrolyte and the lithium metal negative electrode is remarkably improved; the interface impedance is obviously reduced; moreover, compared with the existing methods such as magnetron sputtering, thermal evaporation, chemical vapor deposition and construction of a composite negative electrode, the method has the advantages of simplicity in operation, low cost, no sacrifice of the specific capacity of the negative electrode and good cycle performance of the battery.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of solid-state batteries, and particularly relates to a preparation method of an interface modification layer based on a coffee ring effect, an interface modification layer based on a coffee ring effect prepared by the preparation method, and a solid-state battery. BACKGROUND

[0002] The all-solid-state battery does not contain flammable and volatile organic electrolyte, and can fundamentally solve the safety problem of the current lithium ion battery. Moreover, the new energy storage system of the all-solid-state battery makes it possible to use metal lithium as the negative electrode. The metal lithium has the lowest oxidation potential (-3.04 V), which can improve the discharge voltage of the battery. The ultra-high theoretical specific capacity (3860 mAh·g -1 ) of the metal lithium can reduce the mass ratio of the negative electrode material in the battery, and increase the energy density to 400-700 Wh·kg -1 . However, the surface of the inorganic solid-state electrolyte represented by the garnet LLZO is easy to form carbonate and other pollutants, which leads to poor wettability of the electrolyte and lithium metal, poor negative electrode interface contact, and large interface impedance. Especially in the process of cycling, the uneven stripping of lithium will lead to the formation and growth of interface voids, which will further deteriorate the interface contact, and in severe cases, will induce the growth of lithium dendrites and penetrate the electrolyte.

[0003] In order to improve the interface performance of the electrolyte and the lithium metal, at present, a lithium-friendly layer is mainly modified on the surface of the electrolyte by atomic layer deposition, thermal evaporation, magnetron sputtering and other methods, but the above methods have high requirements for equipment, complex process and high price. There are also methods of adding graphite, C3N4 and other substances in the lithium metal to improve the wettability of the lithium metal and the electrolyte and enhance the interface contact, but such methods will reduce the specific capacity of the negative electrode and sacrifice the energy density of the battery.

[0004] Patent CN119481253A discloses a preparation method and application of a high-entropy alloy interface modification layer for garnet solid-state lithium battery. A high-entropy alloy TiCrCoNiAl is used as a target material, and the high-entropy alloy is deposited on the surface of a garnet solid electrolyte sheet by magnetron sputtering to prepare it. The diameter and thickness of the high-entropy alloy TiCrCoNiAl target material are 50.8 mm and 3 mm, respectively. The element contents of Ti, Cr, Co, Ni, and Al in the target material are 20.9 wt%, 22.7 wt%, 25.8 wt%, 25.6 wt%, and 5 wt%, respectively. The preparation method and application of the high-entropy alloy interface modification layer for garnet solid-state lithium battery provided by the invention have more excellent comprehensive performance compared with traditional single metal or alloy modification layers. By introducing a high-entropy alloy interface modification layer with a thickness of about 200 nm between the garnet solid-state electrolyte and the lithium negative electrode, the side reactions caused by direct contact between the electrolyte and the electrode material can be effectively reduced, the interface contact can be improved, the uniform deposition of Li + However, the patent uses magnetron sputtering to prepare the lithiumophilic layer, which requires the preparation of a high-entropy alloy TiCrCoNiAl target material, and the cost of magnetron sputtering is relatively high.

[0005] Patent CN115000355A discloses a three-dimensional metal lithium-oxide composite negative electrode, its preparation method and application. The preparation method includes: (1) mixing a three-dimensional conductive framework and a metal solution, and performing a hydrothermal reaction to obtain a base material; or mixing a three-dimensional conductive framework, a metal solution, and an imidazole solution, and performing a heat treatment to obtain a base material; the metal elements in the metal solution include any one or a combination of at least two of vanadium, tin, zinc, and cobalt, and the base material includes a three-dimensional conductive framework and a metal oxide generated in situ on the surface of the three-dimensional conductive framework; (2) mixing the base material and molten lithium to obtain a three-dimensional metal lithium-oxide composite negative electrode. The three-dimensional conductive framework and the lithiumophilic oxide in the negative electrode of the invention synergistically inhibit the generation of lithium dendrites, have a large specific surface area and good morphology, can uniformly conduct electric charge, reduce local charge density, inhibit negative electrode volume expansion, and have high capacity and cycle stability in a full-solid-state lithium metal battery. However, the patent introduces a three-dimensional conductive framework into the lithium metal negative electrode and introduces a lithiumophilic oxide on the three-dimensional conductive framework to construct a three-dimensional metal framework-lithium metal-oxide composite negative electrode, which reduces the theoretical specific capacity of the negative electrode.

[0006] Therefore, there is an urgent need to develop a new method for improving the interface performance of solid-state electrolyte and lithium metal, which can reduce cost and simplify operation without sacrificing the specific capacity of the negative electrode, while improving the cycle performance of the battery. SUMMARY

[0007] In view of the defects in the prior art, the purpose of the present application is to provide a preparation method of an interface modification layer based on coffee ring effect, an interface modification layer based on coffee ring effect prepared by the preparation method, and a solid-state battery. The preparation method of the interface modification layer based on coffee ring effect provided by the present application sprays a metal salt precursor solution on the surface of a high-temperature solid-state electrolyte, and utilizes the coffee ring effect to rapidly evaporate and decompose the metal salt precursor solution on the surface of the solid-state electrolyte, thereby forming a plurality of micron ring structures on the surface of the solid-state electrolyte to prepare the interface cross-linking layer. The method of the present application significantly improves the interface contact between the solid-state electrolyte and the lithium metal negative electrode, significantly reduces the interface impedance, and has the advantages of simple operation, low cost, no sacrifice of negative electrode specific capacity, and good battery cycle performance compared with the existing magnetron sputtering, thermal evaporation, chemical vapor deposition, and composite negative electrode construction methods.

[0008] To achieve the above purpose, the first aspect of the present application provides a preparation method of an interface modification layer based on coffee ring effect, the preparation method comprising: spraying a metal salt precursor solution on the surface of a high-temperature solid-state electrolyte to form a plurality of ring structures on the surface of the solid-state electrolyte to prepare the interface modification layer.

[0009] In some embodiments, the spraying mode is compressed air spraying, the pressure of the compressed air is 0.4-0.8 MPa, and the spraying time is 10-1000 s.

[0010] In some embodiments, the spraying mode is selected from continuous spraying and / or pulse spraying.

[0011] In some embodiments, the temperature of the high-temperature solid-state electrolyte is 200-400℃.

[0012] In some embodiments, the concentration of the metal salt precursor solution is 0.02-0.5 M.

[0013] In some embodiments, the solute of the metal salt precursor solution includes a metal inorganic salt and / or a metal organic salt; and the solvent of the metal salt precursor solution includes water and / or an organic solvent.

[0014] In some embodiments, the metal inorganic salt includes a metal nitrate and / or a metal acetate; and the metal organic salt includes one or more of a p-toluenesulfonate, an acetylacetone salt, and a 2-ethylhexanoate.

[0015] In some embodiments, the metal includes one or more of Mg, Zn, Sn, Al, Ag, and Bi.

[0016] In some embodiments, the organic solvent comprises one or more of ethanol, isopropanol, dimethyl sulfoxide (DMSO), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), propylene carbonate (PC), N-methyl pyrrolidone (NMP), and acetone.

[0017] The second aspect of the present application provides an interface modification layer based on the coffee ring effect, which is prepared by the method of the first aspect of the present application.

[0018] The third aspect of the present application provides a solid-state battery, which comprises a solid-state electrolyte and a lithium metal anode, wherein the surface of the solid-state electrolyte is formed with an interface modification layer based on the coffee ring effect as described in the second aspect of the present application.

[0019] Compared with the prior art, the present application has the following advantages: The preparation method of the interface modification layer based on the coffee ring effect provided by the present application uses a spraying method to utilize the coffee ring effect to make the lithiumophilic metal salt precursor solution sprayed on the surface of the high-temperature solid-state electrolyte evaporate rapidly. Due to the faster evaporation rate of the edge part, the liquid flows from the center to the edge to make up for the evaporation loss, eventually causing the solute to deposit in a ring structure at the edge of the droplet. Moreover, the solute will decompose into lithiumophilic oxide ring structures at high temperature. These ring structures collectively constitute a plurality of micron lithiumophilic ring structure patterns. This method significantly improves the interface contact between the solid-state electrolyte and the lithium metal anode, and significantly reduces the interface impedance. Moreover, compared with the existing methods such as magnetron sputtering, thermal evaporation, chemical vapor deposition, and building a composite anode, this method also has the advantages of simple operation, low cost, no sacrifice of anode specific capacity, and good battery cycle performance. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0021] Figure 1 A schematic diagram of the interface modification layer (lithiophilic layer) provided by the present application, which is formed on the surface of the solid-state electrolyte and has a plurality of micron lithiumophilic ring structure patterns, is shown. DETAILED DESCRIPTION

[0022] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the embodiments of the present application and the drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work belong to the scope of protection of the present application.

[0023] In order to improve the interface performance of the electrolyte and the lithium metal, at present, a lithiumophilic layer is mainly modified on the surface of the electrolyte by means of atomic layer deposition, thermal evaporation, magnetron sputtering and the like, but the above-mentioned methods have high requirements for equipment, complex process and high price. There is also a method of adding graphite, C3N4 and the like into the lithium metal to improve the wettability of the lithium metal and the electrolyte and to enhance the interface contact, but this kind of method will reduce the specific capacity of the negative electrode and sacrifice the energy density of the battery. In addition, there is also a method of constructing a composite negative electrode, which will still sacrifice the specific capacity of the negative electrode.

[0024] In view of this, the present application provides a preparation method of an interface modification layer based on coffee ring effect, an interface modification layer based on coffee ring effect prepared by the preparation method and a solid-state battery, so as to solve the problems of poor interface contact between the solid-state electrolyte and the lithium metal negative electrode and the complex operation, high cost, sacrifice of the specific capacity of the negative electrode and poor cycle performance of the battery of the existing methods for improving the interface performance of the electrolyte and the lithium metal.

[0025] In the first aspect, the embodiments of the present application provide a preparation method of an interface modification layer based on coffee ring effect, which comprises: spraying a metal salt precursor solution on the surface of a high-temperature solid-state electrolyte to form a plurality of ring structures on the surface of the solid-state electrolyte, so as to prepare the interface modification layer.

[0026] In the preparation method of the interface modification layer based on coffee ring effect provided by the present application, the spraying method is adopted to drop the lithiumophilic metal salt precursor solution on the surface of the high-temperature solid-state electrolyte, and by means of the coffee ring effect, when the sprayed lithiumophilic metal salt precursor droplet is rapidly evaporated on the surface of the high-temperature solid-state electrolyte, the evaporation rate of the edge part is faster, so that the liquid flows from the center to the edge to make up for the evaporation loss, finally resulting in the deposition of solute at the edge of the droplet to form a ring structure, and moreover, the solute will decompose into a lithiumophilic oxide ring structure at high temperature, and these ring structures jointly constitute a plurality of micron lithiumophilic ring structure patterns (such as shown in FIG. 1), so as to prepare the interface modification layer. This method significantly improves the interface contact between the solid-state electrolyte and the lithium metal negative electrode, and the interface impedance is significantly reduced; moreover, compared with the existing methods such as magnetron sputtering, thermal evaporation, chemical vapor deposition and construction of a composite negative electrode, this method also has the advantages of simple operation, low cost, no sacrifice of the specific capacity of the negative electrode and good cycle performance of the battery. Figure 1 In the preparation method of the interface modification layer based on coffee ring effect provided by the present application, the spraying method is adopted to drop the lithiumophilic metal salt precursor solution on the surface of the high-temperature solid-state electrolyte, and by means of the coffee ring effect, when the sprayed lithiumophilic metal salt precursor droplet is rapidly evaporated on the surface of the high-temperature solid-state electrolyte, the evaporation rate of the edge part is faster, so that the liquid flows from the center to the edge to make up for the evaporation loss, finally resulting in the deposition of solute at the edge of the droplet to form a ring structure, and moreover, the solute will decompose into a lithiumophilic oxide ring structure at high temperature, and these ring structures jointly constitute a plurality of micron lithiumophilic ring structure patterns (such as shown in FIG. 1), so as to prepare the interface modification layer. This method significantly improves the interface contact between the solid-state electrolyte and the lithium metal negative electrode, and the interface impedance is significantly reduced; moreover, compared with the existing methods such as magnetron sputtering, thermal evaporation, chemical vapor deposition and construction of a composite negative electrode, this method also has the advantages of simple operation, low cost, no sacrifice of the specific capacity of the negative electrode and good cycle performance of the battery.

[0027] In the above-mentioned method for preparing the interface modification layer based on the coffee ring effect, an interface modification layer with multiple micron-sized lithiophilic ring structure patterns is prepared on the surface of a solid electrolyte by compressed air spraying. Specifically, a metal salt precursor solution is sprayed onto the surface of a high-temperature solid electrolyte using compressed air, with the compressed air pressure controlled at 0.4~0.8 MPa and the spraying time at 10~1000 s.

[0028] In this invention, the pressure of the compressed air in the compressed air spraying process needs to be controlled to be 0.4~0.8MPa and the spraying time to be 10~1000s, preferably 60~180s. If the above-mentioned spraying process is not controlled, the multiple ring structures formed will overlap excessively, forming an excessively thick lithiophilic layer. An excessively thick lithiophilic layer will hinder the diffusion of lithium ions at the interface.

[0029] In the above method for preparing the interface modification layer based on the coffee ring effect, the spraying method is not specifically limited. For example, continuous spraying and / or pulse spraying can be used.

[0030] In the above-mentioned method for preparing the interface modification layer based on the coffee ring effect, the solid electrolyte needs to be heated to obtain the high-temperature solid electrolyte, and the temperature of the high-temperature solid electrolyte is 200~400℃.

[0031] In this invention, the temperature of the high-temperature solid electrolyte is set to 200~400℃ to ensure the effective decomposition of the metal salt.

[0032] For example, the heating method can be either flat plate heating or oven heating, and there is no limitation on the method.

[0033] In the above-mentioned method for preparing the interface modification layer based on the coffee ring effect, the metal salt precursor solution provides the lithium affinity of the final interface modification layer.

[0034] In the above-described method for preparing the interface modification layer based on the coffee ring effect, a metal salt precursor solution of a certain concentration (referring to the solute concentration) is required. Controlling the concentration of the metal salt precursor solution aims to better form the ring structure. If the concentration of the metal salt precursor solution is too low, the resulting lithium-loving interface modification layer will have a poor effect on improving interfacial wettability; if the concentration of the metal salt precursor solution is too high, the metal oxide at the edge of the ring structure will be too thick, hindering lithium-ion diffusion.

[0035] In some preferred embodiments, the concentration of the metal salt precursor solution is 0.02~0.5M. In a further preferred embodiment, the concentration of the metal salt precursor solution is 0.02~0.05M.

[0036] In some preferred embodiments, the solute in the metal salt precursor solution comprises an inorganic metal salt and / or an organometallic salt. In a further preferred embodiment, the inorganic metal salt comprises one or more of a metal nitrate and / or a metal acetate; the organometallic salt comprises one or more of p-toluenesulfonate, acetylacetone, and 2-ethylhexanoate.

[0037] In some preferred embodiments, the solvent of the metal salt precursor solution includes water and / or an organic solvent. In further preferred embodiments, the organic solvent includes one or more of ethanol, isopropanol, dimethyl sulfoxide (DMSO), dimethyl carbonate (DMC), diethyl carbonate (DEC), methyl ethyl carbonate (EMC), propylene carbonate (PC), N-methylpyrrolidone (NMP), and acetone.

[0038] In some preferred embodiments, the metal includes one or more of Mg, Zn, Sn, Al, Ag, and Bi. Therefore, typical examples of the above-mentioned inorganic metal salts include, but are not limited to, nitrates and acetates corresponding to the metals Mg, Zn, Sn, Al, Ag, and Bi; typical examples of the above-mentioned organometallic salts include, but are not limited to, p-toluenesulfonate, acetylacetone salt, and 2-ethylhexanoate corresponding to the metals Mg, Zn, Sn, Al, Ag, and Bi.

[0039] In some specific embodiments, the preparation method of an interface modification layer based on the coffee ring effect provided by the present invention includes the following steps: S1, Prepare a metal salt precursor solution with a concentration of 0.02~0.5M, wherein the solute includes inorganic metal salts and / or organometallic salts; and the solvent includes water and / or organic solvents. S2, heating the solid electrolyte to 200~400℃; S3, using compressed air to spray the metal salt precursor solution onto the surface of a high-temperature solid electrolyte, controlling the pressure of the compressed air to be 0.4~0.8MPa, and the spraying time to be 10~1000s, preferably 60~180s; the spraying method is continuous spraying or pulse spraying, so as to form an interface modification layer with multiple micron-sized lithiophilic ring structure patterns on the surface of the solid electrolyte.

[0040] Secondly, embodiments of the present invention also provide an interface modification layer based on the coffee ring effect, prepared using the method described in the first aspect of the present invention. This interface modification layer has multiple micron-sized lithiophilic ring structure patterns. This interface modification layer improves the interfacial contact between the solid electrolyte and the lithium metal anode, and significantly reduces the interfacial impedance.

[0041] Thirdly, embodiments of the present invention also provide a solid-state battery, the solid-state battery comprising a solid electrolyte and a lithium metal anode, wherein an interface modification layer based on the coffee ring effect as described in the second aspect of the present invention is formed on the surface of the solid electrolyte.

[0042] In the aforementioned solid-state battery, the solid electrolyte is preferably an inorganic solid electrolyte, and more preferably an oxide solid electrolyte. The oxide solid electrolyte includes one or more of garnet-type solid electrolyte (LLZTO), perovskite-type solid electrolyte (LLTO), and NASICON-type solid electrolyte (LATP).

[0043] Unless otherwise specified, all raw materials used in the embodiments of the present invention are commercially available, all instruments and equipment used are conventional instruments and equipment in the art, and all operating methods used are conventional methods in the art.

[0044] Example Example 1 A 0.02 M Zn(CH3COO)2 precursor solution was prepared using water as a solvent. The precursor solution was then continuously sprayed onto a garnet-type solid electrolyte, Li, at 350 °C using compressed air at 0.8 MPa. 6.4 La3Zr 1.4 Ta 0.6 O 12 The LLZTO surface was sprayed for 60 seconds to form an interface modification layer with multiple micron-sized lithiophilic ring structures on the solid electrolyte surface. The solid electrolyte with the interface modification layer was then assembled into a lithium-lithium symmetric battery (LLZTO / Li symmetric battery modified with the Li / lithiophilic interface modification layer). The battery was heated to 150°C for 5 minutes to promote the reaction between the lithiophilic interface modification layer and metallic lithium. The battery was then encapsulated in a coin cell case, and electrochemical impedance spectroscopy was performed at a frequency of 1~10. 6 Hz. After impedance testing, lithium stripping / deposition testing was performed under the following conditions: 0.2 mA·cm⁻¹. -2 Deposition / stripping at a surface current density, with a single stripping / deposition surface capacity of 0.4 mAh·cm³. -2 The test results are shown in Table 1.

[0045] Example 2 A mixed precursor solution of 0.01 M Zn(CH3COO)2 and 0.01 M Mg(NO3)2 was prepared using water solvent. The mixed precursor solution was then continuously sprayed onto a garnet-type solid electrolyte Li at 350 °C using compressed air at 0.8 MPa. 6.4 La3Zr 1.4 Ta 0.6 O 12The LLZTO surface was sprayed for 60 seconds to form an interface modification layer with multiple micron-sized lithiophilic ring structures on the solid electrolyte surface. The solid electrolyte with the interface modification layer was then assembled into a lithium-lithium symmetric battery (LLZTO / Li symmetric battery modified with the Li / lithiophilic interface modification layer). The battery was heated to 150°C for 5 minutes to promote the reaction between the lithiophilic interface modification layer and metallic lithium. The battery was then encapsulated in a coin cell case, and electrochemical impedance spectroscopy was performed at a frequency of 1~10. 6 Hz. After impedance testing, lithium stripping / deposition testing was performed under the following conditions: 0.2 mA·cm⁻¹. -2 Deposition / stripping at a surface current density, with a single stripping / deposition surface capacity of 0.4 mAh·cm³. -2 The test results are shown in Table 1.

[0046] Example 3 A mixed precursor solution of 0.01 M Zn(CH3COO)2 and 0.01 M Mg(NO3)2 was prepared using water solvent. The mixed precursor solution was then continuously sprayed onto a garnet-type solid electrolyte Li at 350 °C using compressed air at 0.8 MPa. 6.4 La3Zr 1.4 Ta 0.6 O 12 The LLZTO surface was sprayed for 30 seconds to form an interface modification layer with multiple micron-sized lithiophilic ring structures on the solid electrolyte surface. The solid electrolyte with the interface modification layer was then assembled into a lithium-lithium symmetric battery (LLZTO / Li symmetric battery modified with the Li / lithiophilic interface modification layer). The battery was heated to 150°C for 5 minutes to promote the reaction between the lithiophilic interface modification layer and metallic lithium. The battery was then encapsulated in a coin cell case, and electrochemical impedance spectroscopy was performed at a frequency of 1~10. 6 Hz. After impedance testing, lithium stripping / deposition testing was performed under the following conditions: 0.2 mA·cm⁻¹. -2 Deposition / stripping at a surface current density, with a single stripping / deposition surface capacity of 0.4 mAh·cm³. -2 The test results are shown in Table 1.

[0047] Example 4 A mixed precursor solution of 0.01 M Zn(CH3COO)2 and 0.01 M Mg(NO3)2 was prepared using water solvent. The mixed precursor solution was then continuously sprayed onto a garnet-type solid electrolyte Li at 350 °C using compressed air at 0.8 MPa. 6.4 La3Zr 1.4 Ta 0.6 O 12The LLZTO surface was sprayed for 180 seconds to form an interface modification layer with multiple micron-sized lithiophilic ring structures on the solid electrolyte surface. The solid electrolyte with the interface modification layer was then assembled into a lithium-lithium symmetric battery (LLZTO / Li symmetric battery modified with the Li / lithiophilic interface modification layer). The battery was heated to 150°C for 5 minutes to promote the reaction between the lithiophilic interface modification layer and metallic lithium. The battery was then encapsulated in a coin cell case, and electrochemical impedance spectroscopy was performed at a frequency of 1~10. 6 Hz. After impedance testing, lithium stripping / deposition testing was performed under the following conditions: 0.2 mA·cm⁻¹. -2 Deposition / stripping at a surface current density, with a single stripping / deposition surface capacity of 0.4 mAh·cm³. -2 The test results are shown in Table 1.

[0048] Example 5 A mixed precursor solution of 0.01 M Zn(CH3COO)2 and 0.01 M Mg(NO3)2 was prepared using water solvent. The mixed precursor solution was then continuously sprayed onto a garnet-type solid electrolyte Li at 350 °C using compressed air at 0.8 MPa. 6.4 La3Zr 1.4 Ta 0.6 O 12 The LLZTO surface was sprayed for 600 seconds to form an interface modification layer with multiple micron-sized lithiophilic ring structures on the solid electrolyte surface. The solid electrolyte with the interface modification layer was then assembled into a lithium-lithium symmetric battery (LLZTO / Li symmetric battery modified with the Li / lithiophilic interface modification layer). The battery was heated to 150°C for 5 minutes to promote the reaction between the lithiophilic interface modification layer and metallic lithium. The battery was then encapsulated in a coin cell case, and electrochemical impedance spectroscopy was performed at a frequency of 1~10. 6 Hz. After impedance testing, lithium stripping / deposition testing was performed under the following conditions: 0.2 mA·cm⁻¹. -2 Deposition / stripping at a surface current density, with a single stripping / deposition surface capacity of 0.4 mAh·cm³. -2 The test results are shown in Table 1.

[0049] Example 6 A mixed precursor solution of 0.03 M Zn(CH3COO)2 and 0.02 M Mg(NO3)2 was prepared using water solvent. The mixed precursor solution was then continuously sprayed onto a garnet-type solid electrolyte Li3 at 350 °C using compressed air at 0.8 MPa. 6.4 La3Zr 1.4 Ta 0.6 O 12The LLZTO surface was sprayed for 60 seconds to form an interface modification layer with multiple micron-sized lithiophilic ring structures on the solid electrolyte surface. The solid electrolyte with the interface modification layer was then assembled into a lithium-lithium symmetric battery (LLZTO / Li symmetric battery modified with the Li / lithiophilic interface modification layer). The battery was heated to 150°C for 5 minutes to promote the reaction between the lithiophilic interface modification layer and metallic lithium. The battery was then encapsulated in a coin cell case, and electrochemical impedance spectroscopy was performed at a frequency of 1~10. 6 Hz. After impedance testing, lithium stripping / deposition testing was performed under the following conditions: 0.2 mA·cm⁻¹. -2 Deposition / stripping at a surface current density, with a single stripping / deposition surface capacity of 0.4 mAh·cm³. -2 The test results are shown in Table 1.

[0050] Example 7 A mixed precursor solution of 0.3 M Zn(CH3COO)2 and 0.2 M Mg(NO3)2 was prepared using water solvent. The mixed precursor solution was then continuously sprayed onto a garnet-type solid electrolyte Li at 350 °C using compressed air at 0.8 MPa. 6.4 La3Zr 1.4 Ta 0.6 O 12 The LLZTO surface was sprayed for 60 seconds to form an interface modification layer with multiple micron-sized lithiophilic ring structures on the solid electrolyte surface. The solid electrolyte with the interface modification layer was then assembled into a lithium-lithium symmetric battery (LLZTO / Li symmetric battery modified with the Li / lithiophilic interface modification layer). The battery was heated to 150°C for 5 minutes to promote the reaction between the lithiophilic interface modification layer and metallic lithium. The battery was then encapsulated in a coin cell case, and electrochemical impedance spectroscopy was performed at a frequency of 1~10. 6 Hz. After impedance testing, lithium stripping / deposition testing was performed under the following conditions: 0.2 mA·cm⁻¹. -2 Deposition / stripping at a surface current density, with a single stripping / deposition surface capacity of 0.4 mAh·cm³. -2 The test results are shown in Table 1.

[0051] Example 8 A 0.02 M zinc acetylacetone precursor solution was prepared using methanol solvent. The precursor solution was then continuously sprayed onto a garnet-type solid electrolyte Li₂ at 350 °C using compressed air at 0.8 MPa. 6.4 La3Zr 1.4 Ta 0.6 O 12The LLZTO surface was sprayed for 60 seconds to form an interface modification layer with multiple micron-sized lithiophilic ring structures on the solid electrolyte surface. The solid electrolyte with the interface modification layer was then assembled into a lithium-lithium symmetric battery (LLZTO / Li symmetric battery modified with the Li / lithiophilic interface modification layer). The battery was heated to 150°C for 5 minutes to promote the reaction between the lithiophilic interface modification layer and metallic lithium. The battery was then encapsulated in a coin cell case, and electrochemical impedance spectroscopy was performed at a frequency of 1~10. 6 Hz. After impedance testing, lithium stripping / deposition testing was performed under the following conditions: 0.2 mA·cm⁻¹. -2 Deposition / stripping at a surface current density, with a single stripping / deposition surface capacity of 0.4 mAh·cm³. -2 The test results are shown in Table 1.

[0052] Comparative Example 1 Water was continuously sprayed onto a garnet-type solid electrolyte Li at 350℃ using compressed air at 0.8 MPa. 6.4 La3Zr 1.4 Ta 0.6 O 12 The LLZTO surface was sprayed for 60 seconds to obtain the treated solid electrolyte. The solid electrolyte was then used to assemble a lithium-lithium symmetric battery (Li / water-modified LLZTO / Li symmetric battery), held at 150°C for 5 minutes, and then encapsulated in a coin cell. Electrochemical impedance spectroscopy was performed at a frequency of 1~10. 6 Hz. After impedance testing, lithium stripping / deposition testing was performed under the following conditions: 0.2 mA·cm⁻¹. -2 Deposition / stripping at a surface current density, with a single stripping / deposition surface capacity of 0.4 mAh·cm³. -2 The test results are shown in Table 1.

[0053] Table 1 Interfacial impedance and cycle life of lithium-ion symmetric batteries

[0054] As can be seen from Table 1: Compared to Comparative Example 1, the lithium-lithium symmetric batteries prepared using Examples 1-8 of this invention exhibit lower interfacial impedance and longer lithium stripping / deposition lifetime. This demonstrates that the method for preparing the interface modification layer based on the coffee ring effect provided by this invention significantly improves the interfacial contact between the solid electrolyte and the lithium metal anode, resulting in a significant reduction in interfacial impedance and better battery cycle performance. Moreover, compared to existing methods such as magnetron sputtering, thermal evaporation, chemical vapor deposition, and the construction of composite anodes, the method of this invention is simple to operate and low in cost. Furthermore, since it does not require the introduction of a three-dimensional conductive framework or the addition of other substances to the lithium metal, this invention does not sacrifice the specific capacity of the anode.

[0055] In the description of this specification, the references to terms such as "one embodiment / mode," "some embodiments / modes," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment / mode or example is included in at least one embodiment / mode or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment / mode or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments / modes or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments / modes or examples described in this specification, as well as the features of different embodiments / modes or examples.

[0056] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. In this application, "a plurality of" means at least two, such as two, three, etc., unless otherwise expressly specified.

[0057] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for preparing an interface modification layer based on the coffee ring effect, characterized in that, The preparation method comprises: spraying a metal salt precursor solution on the surface of a high-temperature solid-state electrolyte to form a plurality of ring structures on the surface of the solid-state electrolyte, thereby obtaining the interface modification layer.

2. The method for preparing an interface modification layer based on the coffee- ring effect according to claim 1, characterized in that, The spraying mode is compressed air spraying, the pressure of the compressed air is 0.4-0.8 MPa, and the spraying time is 10-1000 s.

3. The method for preparing an interface modification layer based on the coffee- ring effect according to claim 1, characterized in that, The spraying mode is selected from continuous spraying and / or pulse spraying.

4. The method for preparing an interface modification layer based on the coffee- ring effect according to claim 1, characterized in that, The temperature of the high-temperature solid-state electrolyte is 200-400 ℃.

5. The method for preparing an interface modification layer based on the coffee- ring effect according to claim 1, characterized in that, The concentration of the metal salt precursor solution is 0.02-0.5 M.

6. The method for preparing an interface modification layer based on the coffee- ring effect according to claim 1, characterized in that, The solute of the metal salt precursor solution comprises a metal inorganic salt and / or a metal organic salt; and the solvent of the metal salt precursor solution comprises water and / or an organic solvent.

7. The method for preparing an interface modification layer based on the coffee- ring effect according to claim 6, characterized in that, The metal inorganic salt comprises a metal nitrate and / or a metal acetate; and the metal organic salt comprises one or more of a p-toluenesulfonate, an acetylacetone salt and a 2-ethylhexanoate.

8. The method for preparing an interface modification layer based on the coffee- ring effect according to any one of claims 5 to 7, characterized in that, The metal comprises one or more of Mg, Zn, Sn, Al, Ag and Bi.

9. The method for preparing an interface modification layer based on the coffee- ring effect according to claim 6, characterized in that, The organic solvent comprises one or more of ethanol, isopropyl alcohol, dimethyl sulfoxide (DMSO), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), propylene carbonate (PC), N-methyl pyrrolidone (NMP) and acetone.

10. An interface modification layer based on the coffee ring effect, which is prepared by the method according to any one of claims 1-9.

11. A solid state battery, characterized by The solid-state battery comprises a solid-state electrolyte and a lithium metal anode, wherein the surface of the solid-state electrolyte is provided with the interface modification layer based on the coffee ring effect according to claim 10.

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