Solid electrolyte composite materials and their applications in lithium batteries

Abstract

The present invention relates to the technical field of lithium metal batteries, in particular to a solid electrolyte composite material and its application in lithium batteries. The solid electrolyte composite material comprises a compound containing a multiamide group structure as shown in the following formula, and a sulfide solid electrolyte material; NH2-R-NH-[-OC-R-CO-NH-R-NH-] n The present invention uses the compound of formula (1) as a lithium negative electrode protective additive and compounds it with a sulfide solid electrolyte material to obtain a solid electrolyte composite material with a protective function for the lithium negative electrode.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium metal batteries, in particular to a solid electrolyte composite material and its application and a lithium battery. Background Art

[0002] Lithium metal batteries have achieved rapid development in the fields of electronic equipment and power supplies due to their advantages such as high energy density, high operating voltage and long cycle life. However, most of the lithium metal batteries currently developed use flammable and leaky organic electrolytes, which leads to serious safety hazards. In contrast, replacing the organic electrolyte with a solid electrolyte layer can effectively solve the safety problems of lithium metal batteries. At the same time, the use of high-energy-density electrode sheets such as metallic lithium can effectively improve the energy density of the battery system, thereby realizing the development of high-energy-density power batteries. However, due to the strong reducing properties of negative electrode materials such as metallic lithium, the currently developed solid electrolyte materials such as sulfide electrolyte materials, oxide electrolyte materials and halide electrolyte materials generally have problems such as instability with lithium, which seriously restricts their application.

[0003] When solid electrolyte materials are directly exposed to a strongly reducing negative electrode such as metallic lithium or to lithium alloy intermediates formed during the electrochemical cycle, severe chemical reactions will occur at the interface between the electrolyte material and the negative electrode material such as metallic lithium, producing a surface passivation film that hinders electron / ion conduction, or producing lithium dendrites, etc., which will cause the battery's cycle life and safety performance to continue to deteriorate. In order to overcome this problem, researchers usually pre-fabricate a protective film on the surface of metallic lithium and other electrodes. The protective film can alleviate the chemical reaction between the electrolyte and high-energy-density negative electrodes such as lithium, and at the same time alleviate the formation of lithium dendrites, thereby obtaining a long-cycle all-solid-state lithium metal battery. However, the process of pre-treating the surface of metallic lithium often requires harsh experimental conditions, such as using an anhydrous and oxygen-free atmosphere in a glove box. At the same time, due to the strong reducing properties of metallic lithium and its soft and easy diffusion behavior, the protective film obtained by pre-treatment of the surface of metallic lithium is difficult to preserve for a long time, which can easily lead to problems such as poor consistency and damaged film uniformity, which seriously restricts its application. Summary of the Invention

[0004] The present invention aims to solve one of the technical problems in the prior art at least to some extent, or at least provide a commercial choice.

[0005] The present invention provides a solid electrolyte composite material, which uses the compound of the following formula (1) as a lithium negative electrode protective additive and is compounded with a sulfide solid electrolyte material to obtain a solid electrolyte composite material with a protective function for the lithium negative electrode.

[0006] A solid electrolyte composite material, comprising a compound containing a multi-amide group structure as shown in formula (1), and a sulfide solid electrolyte material;

[0007] NH2-R-NH-[-OC-R-CO-NH-R-NH-] n -OC-R-COOH formula (1)

[0008] Wherein, R is a hydrocarbon group, a substituted hydrocarbon group, an oxyalkyl group or an aromatic hydrocarbon group containing a benzene ring; n is greater than or equal to 10, specifically, n mainly ranges from 10 to 100 to form a polymer chain segment.

[0009] The sulfide solid electrolyte material is one or more of the following inorganic fast ion conductors, including: sulfide solid electrolyte material argyrodite Li6PS5X and its derivatives, X=one or more of F, Cl, Br, I; Li 6+ a Sb 1-a Si a S5I and its derivatives, 0.1≤a≤0.75; lithium germanium phosphorus sulfur phase Li 10 MP2S 12 and its derivatives, M=one or more of Si, Ge, Sn, Zn, Al; lithium phosphorus sulfur phase Li3PS4 phase and its derivatives; Li7P3S 11 Phase and its derivatives; Li4MS4 phase and its derivatives, M=Si, Sn, Ge.

[0010] Specifically, R is a hydrocarbon group or a substituted hydrocarbon group having 1 to 10 carbon atoms; further, R is selected from any one of an alkyl group, an alkylene group, a haloalkyl group, a haloalkylene group, an alkenyl group, an alkenylene group, a haloalkenyl group, a haloalkenylene group, an aryl group, an arylene group, a haloaryl group, and a haloarylene group. The halogen is selected from fluorine, chlorine, bromine, and iodine, and the halo is fully halogenated or partially halogenated.

[0011] Furthermore, in order to obtain better performance, the compound containing a multi-amide group structure shown in formula (1) can be modified with end groups and amide functional groups.

[0012] Specifically, the terminal groups and amide functional groups are modified by halogenation, acid treatment, alkali treatment, or methylation treatment.

[0013] Specifically, the halogenation treatment method uses hydrogen chloride, hydrogen fluoride, hydrogen bromide, hydrogen iodide, chlorine, bromine, iodine vapor, POX3, PSX3, and PNX2 for treatment (such as fumigation); or uses an organic solution containing hydrogen chloride, hydrogen fluoride, hydrogen bromide, hydrogen iodide, chlorine, bromine, iodine vapor, POX3, PSX3, and PNX2 for soaking-drying-heat treatment, where X is one or more of F, Cl, Br, and I.

[0014] Furthermore, the halogenation treatment method is to use a substance containing hydrogen chloride, hydrogen fluoride, hydrogen bromide, hydrogen iodide, chlorine, bromine, iodine vapor, POX3, PSX3, and PNX2 for heating fumigation in a sealed or flowing atmosphere, and the fumigation temperature is lower than 200 degrees Celsius; or a solution containing hydrogen chloride, hydrogen fluoride, hydrogen bromide, hydrogen iodide, chlorine, bromine, iodine vapor, POX3, PSX3, and PNX2 is mixed-dried-heat treated, where X is one or more of F, Cl, Br, and I; the solution is an organic solution, and an alcohol, ester, ether, or hydrocarbon solvent is used.

[0015] Specifically, the acid treatment is treatment using an acidic solution, and the alkali treatment is treatment using an alkaline solution.

[0016] Specifically, the methylation treatment is carried out by soaking in a solvent containing hydrocarbon functional groups and drying the solvent.

[0017] In some embodiments, the compound containing a multi-amide group structure represented by formula (1) is selected from a polybutylene adipamide polymer compound, a polybutylene phthalamide polymer compound, a polybutylene phthalamide polymer compound whose end groups are modified by fumigation with iodine vapor, and a polybutylene phthalamide polymer compound whose end groups are modified by fumigation with POCl3 vapor.

[0018] Specifically, the argyrodite Li6PS5X and its derivatives include: Li6PS5Cl; Li 6- x PS 5-x X 1+x , 0<x<0.7, X is one or more of F, Cl, Br, I; oxygen-doped Li 6-x PS 5-x-y X 1+x O y , 0<x<0.7, 0<y<1, X is one or more of F, Cl, Br, and I.

[0019] Specifically, the Li 6+a Sb 1-a Si a S5I and its derivatives contain Li 6+a Sb 1-a Si a S5I, 0.1≤a≤0.75; halogen-doped Li 6+a Sb 1-a Si a S5X, 0.1≤a≤0.75, X is one or more of F, Cl, Br, I; oxygen-doped Li 6+ a Sb 1-a Sia S 5-b XO b , 0.1≤a≤0.75, 0.1≤b≤1, X is one or more of F, Cl, Br, I; oxygen-doped Li 6+a+b Sb 1-a Si a S5X 1-b O b , 0.1≤a≤0.75, 0.01≤b≤0.2, X is one or more of F, Cl, Br, and I.

[0020] Specifically, the lithium germanium phosphorus sulfur phase Li 10 MP2S 12 and its derivatives include: Li 10 MP2S 12 , M=one or more of Si, Ge, Sn, Sb, Zn, Al; stoichiometric lithium germanium phosphorus sulfur phase; halogen-doped lithium germanium phosphorus sulfur phase; oxygen-doped lithium germanium phosphorus sulfur phase.

[0021] Specifically, the lithium phosphorus sulfur phase Li3PS4 phase and its derivatives include: Li3PS4; lithium phosphorus sulfur phase with a partial stoichiometric ratio; halogen-doped lithium phosphorus sulfur phase; lithium phosphorus sulfur phase doped with a metal element M and oxygen-doped lithium phosphorus sulfur phase, M = Al, Mg, Si, Sn, Sb.

[0022] Specifically, the Li7P3S 11 Phases and their derivatives include: Li7P3S 11 ; Lithium phosphorus sulfur phase with a partial stoichiometric ratio; halogen-doped lithium phosphorus sulfur phase; lithium phosphorus sulfur phase doped with metal element M and oxygen-doped lithium phosphorus sulfur phase, M = Al, Mg, Si, Sn, Sb.

[0023] In some embodiments, the solid electrolyte composite material is composed of or made of a compound containing a multi-amide group structure as shown in formula (1) and a sulfide solid electrolyte material.

[0024] In some embodiments, in the solid electrolyte composite material, the mass proportion of the compound containing a multi-amide group structure as shown in formula (1) is greater than 0 and less than or equal to 5%.

[0025] In some embodiments, in the solid electrolyte composite material, the mass ratio of the sulfide solid electrolyte material to the compound containing a multi-amide group structure as shown in formula (1) is 1:(0.01-0.025), specifically 1:0.01, 1:0.015, and 1:0.025.

[0026] The present invention also provides a method for preparing the above-mentioned solid electrolyte composite material, comprising: compounding a sulfide solid electrolyte material with a compound containing a polyamide group structure as shown in formula (1). The specific compounding method can be performed by ball milling, grinding, and heat treatment.

[0027] In some specific examples, the composite method includes: weighing and grinding the sulfide solid electrolyte material and the compound containing a multiamide group structure as shown in formula (1) in a glove box, and then ball-milling the composite material using a planetary ball mill after grinding; in order to further enhance the composite effect between the two, the ball-milled sample can be placed in a vacuum quartz tube for heat treatment.

[0028] The present invention also provides application of the solid electrolyte composite material in in-situ protection of lithium negative electrodes.

[0029] By using the above-mentioned solid electrolyte composite material to perform in-situ chemical or electrochemical treatment on metallic lithium, a protective layer rich in nitrogen, halogen and sulfur compounds can be formed in situ on the surface of the lithium metal negative electrode. At the same time, during the battery cycle, the modified or unmodified polyamide group additives are uniformly distributed in the sulfide electrolyte layer to inhibit the nucleation and growth of lithium dendrites in the electrolyte grain boundaries, thereby effectively stabilizing the lithium metal negative electrode, inhibiting the occurrence of short-circuit problems in all-solid-state batteries caused by lithium dendrites, and improving the safety and stability of all-solid-state lithium batteries.

[0030] The present invention also provides a method for in-situ protection of a lithium negative electrode, comprising: contacting the above-mentioned solid electrolyte composite material with the surface of metallic lithium, and adopting an in-situ electrochemical deposition / removal method of metallic lithium to perform in-situ protection on the surface of the metallic lithium negative electrode. Specifically, the above-mentioned solid electrolyte composite material is taken in a glove box or a dry room with a dew point below -40°C, and a ceramic film is obtained through a dry film forming / rolling process. The ceramic film can be directly used as a solid electrolyte membrane in all-solid-state lithium metal or as an interlayer between an electrolyte membrane (electrolyte layer) and a metallic lithium negative electrode. During the electrochemical cycle, the added ceramic film can generate a lithium negative electrode protection film on the metallic lithium surface in situ through the process of electrochemical reaction, or can achieve the function of removing dendrites in the process of dendrite generation in metallic lithium.

[0031] The present invention also provides the application of the solid electrolyte composite material in solid-state batteries as any one of a solid electrolyte, a metal lithium negative electrode stabilizer, and an electrode-electrolyte interface modifier.

[0032] The solid electrolyte composite material of the present invention has a protective function for the lithium negative electrode, and forms a highly stable protective film rich in nitrogen, halogen and sulfur compounds in situ on the surface of metallic lithium or lithium dendrites through electrochemical reactions during the electrochemical cycle.

[0033] The present invention also provides a lithium battery, comprising:

[0034] The above-mentioned solid electrolyte composite material;

[0035] positive electrode;

[0036] a negative electrode; and

[0037] An electrolyte is interposed between the positive electrode and the negative electrode and includes a sulfide solid electrolyte, an oxide solid electrolyte, a halide electrolyte, a nitride electrolyte, a polymer electrolyte, an organic electrolyte, or a combination thereof.

[0038] Specifically, the lithium battery is a lithium-ion battery, including an all-solid battery, a semi-solid battery and a liquid battery.

[0039] By adding the solid electrolyte composite material of the present invention during the battery assembly process, a protective layer of solid electrolyte material is used to form an in-situ protective film rich in lithium, nitrogen, sulfur, and oxygen on the surface of metallic lithium or lithium dendrites during the battery's static, formation, or circulation process, thereby realizing a highly stable and long-cycle solid-state lithium metal battery.

[0040] The solid electrolyte composite material of the present invention is used to improve the commercial application value of lithium metal batteries, including all-solid-state lithium secondary batteries; the commercial application value refers to improving the interface stability of lithium metal batteries, reducing the surface impedance of electrode materials, inhibiting the growth of lithium dendrites, and preventing battery short circuits. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 The performance curve of a lithium symmetric battery obtained by using a lithium negative electrode protection additive prepared in Example 1, a lithium negative electrode in-situ protection method, and a solid electrolyte material capable of realizing the protection function as the electrolyte of an all-solid-state battery.

[0042] Figure 2 The performance curve of a lithium symmetric battery obtained by using a lithium negative electrode protection additive prepared in Example 2, a lithium negative electrode in-situ protection method, and a solid electrolyte material capable of realizing the protection function as the electrolyte of an all-solid-state battery.

[0043] Figure 3 This is the performance curve of a lithium symmetric battery using the solid electrolyte material Li3PS4 obtained in Comparative Example 1 as the electrolyte.

[0044] Figure 4 This is the performance curve of a lithium symmetric battery using the solid electrolyte material obtained in Comparative Example 2 as the electrolyte.

[0045] Chinese and English comparison in the attached figure:

[0046] English Chinese Time time Voltage Voltage DETAILED DESCRIPTION

[0047] The present invention is described below by specific embodiments. Unless otherwise specified, the technical means used in the present invention are methods well known to those skilled in the art. In addition, the embodiments should be understood to be illustrative, rather than limiting, of the scope of the present invention. For those skilled in the art, various changes or modifications to the material components and dosages in these embodiments, without departing from the spirit and scope of the present invention, also fall within the scope of protection of the present invention.

[0048] Example 1

[0049] A solid electrolyte composite material is composed of a lithium-containing solid electrolyte material Li3PS4 and a lithium negative electrode protection additive polybutylene adipamide polymer compound in a mass ratio of 1:0.01.

[0050] Preparation method: A polybutylene adipamide polymer compound is obtained by a chemical method through the polycondensation reaction of dibutylene diamine and adipic acid. The specific process is as follows: (1) Using dibutylene diamine and adipic acid as raw materials, a polybutylene adipamide polymer compound is synthesized in an ethanol solvent; under the condition that the excess ratio of dibutylene diamine is 4 mol.%, a polybutylene adipamide polymer compound solution with a mass concentration of 1% is obtained. (2) Using the generated polybutylene adipamide polymer compound solution as a raw material, a prepolymerization is carried out; the reaction is carried out at 190°C and 1 MPa for 5.5 hours, and 3 mol.% of amine is added to supplement the amine lost during the reaction. (3) The obtained prepolymer is washed with water and dried to obtain the polybutylene adipamide polymer compound as a lithium negative electrode protection additive described in this embodiment.

[0051] Next, 1.0 g of commercially available Li3PS4 sulfide solid electrolyte material and 0.01 g of polybutylene adipamide polymer were weighed in a glove box and ground in a mortar for 30 minutes. The mixture was then placed in a 50 ml agate ball mill, filled with agate balls of various sizes, achieving a ball-to-material ratio of 25:1. The mill was then evacuated and sealed in the glove box and transferred to a ball mill at 250 rpm for 1 hour to produce the solid electrolyte composite material.

[0052] Example 2

[0053] A solid electrolyte composite material comprising a lithium-containing solid electrolyte material Li 5.5 PS 4.5 Cl 1.5 , the lithium negative electrode protection additive polybutylene phthalamide polymer compound is composed of a mass ratio of 1:0.025.

[0054] Preparation method: A polybutylene phthalamide polymer compound is obtained by a polycondensation reaction of butanediamine and phthalic acid. The specific process is: a polybutylene phthalamide polymer compound is obtained by a polycondensation reaction of butanediamine and phthalic acid. The specific process is: (1) a polybutylene phthalamide polymer compound is synthesized in an ethanol solvent using butanediamine and phthalic acid as raw materials; wherein the excess ratio of butanediamine is 4 mol.%, a polybutylene phthalamide polymer compound solution with a mass concentration of 1% is obtained. (2) a prepolymerization is carried out using the generated polybutylene phthalamide polymer compound solution as a raw material; the reaction is carried out at 175°C and 1 MPa for 7 hours, wherein 3 mol.% of amine is added to supplement the amine lost during the reaction. (3) the obtained prepolymer is washed with water and dried to obtain the polybutylene phthalamide polymer compound as a lithium negative electrode protection additive described in this embodiment.

[0055] In the glove box, 1.0 g of commercially available Li with an ionic conductivity of 7 mS / cm was weighed. 5.5 PS 4.5 Cl 1.5 For the materials, 0.025 g of the obtained polybutylene phthalamide polymer was ground in a mortar for 30 minutes. The material was then placed in a 50 ml agate ball mill and filled with agate balls of various sizes, achieving a ball-to-material ratio of 25:1. The mill was evacuated and sealed in a glove box before being transferred to a ball mill at 250 rpm for one hour to yield the solid electrolyte composite material.

[0056] Example 3

[0057] A solid electrolyte composite material comprising a lithium-containing solid electrolyte material Li 5.5 PS 4.5 Cl 1.5 , the lithium negative electrode protection additive is composed of a polybutylene phthalamide polymer compound with terminal modifications fumigated with iodine vapor in a mass ratio of 1:0.015.

[0058] Preparation method: A chemical method is used to obtain an aliphatic polybutylene phthalamide polymer compound through a polycondensation reaction of butanediamine and phthalic acid similar to that in Example 2. Subsequently, 100 mg of the polybutylene phthalamide polymer compound is weighed and placed in a tube furnace. 0.2 g of elemental iodine is placed in front of the polymer compound. An argon atmosphere is introduced and the mixture is heated to 80 degrees Celsius. The polybutylene phthalamide polymer compound is treated with iodine vapor for 5 hours to obtain an iodine vapor-fumigated end-group modified polybutylene phthalamide polymer compound. Subsequently, 1.0 g of commercially purchased Lithium ion conductivity of 7 mS / cm is weighed in a glove box. 5.5 PS 4.5 Cl 1.5For the material, 0.015 g of iodine vapor-fumigated end-group-modified polybutylene phthalamide (PBPA) polymer was ground in a mortar for 30 minutes. The material was then placed in a 50 ml agate milling jar and filled with agate balls of various sizes, achieving a ball-to-material ratio of 25:1. The milling jar was evacuated and sealed in a glove box before being transferred to a ball mill at 250 rpm for one hour to produce the solid electrolyte composite material.

[0059] Example 4

[0060] A solid electrolyte composite material, comprising a lithium-containing solid electrolyte material Li 5.5 PS 4.5 Cl 1.5 , the lithium negative electrode protection additive is a polybutylene phthalamide polymer compound modified by end group fumigation with POCl3 vapor in a mass ratio of 1:0.025.

[0061] Preparation method: Using a chemical method, a polybutylene phthalamide polymer compound is obtained by a condensation reaction of butanediamine and phthalic acid similar to that in Example 2. 100 mg of the polybutylene phthalamide polymer compound and 10 mg of POCl3 are then placed in a sealed screw-cap bottle and heated to 80 degrees Celsius for 5 hours. Then, nitrogen is introduced to blow away the unreacted POCl3; thus, a polybutylene phthalamide polymer compound modified with end groups or amide functional groups by POCl3 vapor fumigation is obtained. 1.0 g of commercially available Lithium ion battery with an ionic conductivity of 7 mS / cm is then weighed in a glove box. 5.5 PS 4.5 Cl 1.5 For the material, 0.015 g of iodine vapor-fumigated end-group-modified polybutylene phthalamide (PBPA) polymer was ground in a mortar for 30 minutes. The material was then placed in a 50 ml agate milling jar and filled with agate balls of various sizes, achieving a ball-to-material ratio of 25:1. The milling jar was evacuated and sealed in a glove box before being transferred to a ball mill at 250 rpm for one hour to produce the solid electrolyte composite material.

[0062] Application Example 1

[0063] The solid electrolyte composite material prepared in Example 1 was used as the solid electrolyte for a solid-state lithium (ion) full battery. The specific operation was as follows:

[0064] In a glove box, 150 mg of the solid electrolyte composite material prepared in Example 1 was weighed and placed in the mold battery liner. After flattening, the electrolyte sheet was pressed using a pressure of 350 MPa. Unmodified lithium sheets were then added to both ends of the electrolyte sheet to test the lithium symmetric battery. Constant current charge and discharge were used for testing, with a current of 0.1 mA cm -2, the time is 10 hours.

[0065] Figure 1 The figure shows the performance curve of a lithium symmetric battery obtained by using the solid electrolyte composite material prepared in Example 1 as the electrolyte of an all-solid-state battery. Figure 1 It is shown that the solid electrolyte composite material prepared in Example 1 is stable to lithium as a solid electrolyte, and no short circuit phenomenon occurs after cycling for more than 400 hours in a lithium symmetric battery.

[0066] Application Example 2

[0067] The solid electrolyte composite material prepared in Example 1 was used as a solid electrolyte additive to prepare a solid-state lithium (ion) full battery. The specific operation was as follows:

[0068] In the glove box, 20 mg of the solid electrolyte composite material prepared in Example 1 and 80 mg of commercially available Li 10 GeP2S 12 The mixed material was placed in a mortar for grinding and mixing. The mixed material was placed in the mold battery liner, flattened, and the electrolyte sheet was pressed with a pressure of 350 MPa. Then, unmodified lithium sheets were added to both ends of the electrolyte sheet to test the lithium symmetric battery. The constant current charge and discharge test was performed with a current of 0.1 mA cm -2 , the time is 10 hours.

[0069] The results show that the solid electrolyte composite material prepared in Example 1 can effectively solve the problem of Li 10 GeP2S 12 Regarding the reaction problem in lithium metal batteries, the lithium symmetric battery can be cycled for >100 hours without any short circuit phenomenon.

[0070] Application Example 3

[0071] The solid electrolyte composite material prepared in Example 4 was used as the solid electrolyte for a solid-state lithium (ion) full battery. The specific operation was as follows:

[0072] In a glove box, 150 mg of the solid electrolyte composite material prepared in Example 4 was weighed and placed in the mold battery liner. After flattening, the electrolyte sheet was pressed using a pressure of 350 MPa. Unmodified lithium sheets were then added to both ends of the electrolyte sheet to test the lithium symmetric battery. Constant current charge and discharge were used for testing, with a current of 0.1 mA cm -2 , the time is 10 hours.

[0073] Figure 2The performance curve of a lithium symmetric battery obtained by using the solid electrolyte composite material prepared in Example 4 as the electrolyte of an all-solid-state battery. Figure 2 It is shown that the solid electrolyte composite material prepared in Example 4 is stable to lithium as a solid electrolyte, and no short circuit phenomenon occurs after 500 hours of cycling in a lithium symmetrical battery.

[0074] Application Example 4

[0075] The solid electrolyte composite material prepared in Example 2 was used as a negative electrode additive in a solid-state lithium (ion) full battery. The specific operation was as follows:

[0076] In the glove box, 30 mg of the solid electrolyte composite material prepared in Example 2 was weighed and mixed with the graphite negative electrode. The mass of the graphite negative electrode was 70 mg. The mixed material was placed in a mortar for grinding and mixing. The material obtained after mixing was the graphite negative electrode powder with additives. Subsequently, 70 mg of commercially purchased lithium cobalt oxide and 30 mg of commercially purchased Li3InCl6 electrolyte material were weighed and ground and mixed in a mortar. After mixing evenly, it was recorded as lithium cobalt oxide positive electrode powder. All-solid-state battery assembly: 70 mg of commercially purchased Li3InCl6 with an ion conductivity of 7 mS / cm was weighed. 5.5 PS 4.5 Cl 1.5 The material is used as an electrolyte and placed in the inner liner of the mold battery. After flattening, the electrolyte sheet is pressed with a pressure of 150MPa. Then, graphite negative electrode powder with additives is added to one end of the electrolyte sheet and spread evenly. Lithium cobalt oxide positive electrode powder is added to the other end and spread evenly. Then, a pressure of 350MPa is used to press the all-solid-state battery. After compaction, an ultra-thin metal lithium electrode sheet less than 1 micron is added to the graphite negative electrode powder as part of the negative electrode, and pressed with a pressure of 50MPa. The inner liner is then transferred to the mold battery for sealing and electrochemical performance testing.

[0077] The results show that the solid electrolyte composite material prepared in Example 2 has good electrochemical performance when used as a graphite negative electrode additive.

[0078] Comparative Example 1

[0079] Only lithium-containing solid electrolyte material Li3PS4 was used as the electrolyte (this material was the same as the lithium-containing solid electrolyte material used in Example 1). Performance testing and comparison were carried out using a method similar to that in Example 1. The test method was constant current charge and discharge with a current of 0.1 mA cm -2 , the difference is that the charge and discharge time is reduced to 1 hour. Figure 3 The performance curve of the lithium symmetric battery using solid electrolyte material Li3PS4 as electrolyte in comparative example 1 is shown in FIG. Figure 1By comparison, it was found that the solid electrolyte material Li3PS4 will produce obvious short circuit phenomenon when used as an electrolyte in a lithium symmetrical battery after cycling for 100 hours.

[0080] Comparative Example 2

[0081] Only lithium-containing solid electrolyte material Li 5.5 PS 4.5 Cl 1.5 As the electrolyte (the material is the same as the lithium-containing solid electrolyte material used in Example 2), a performance test and comparison were carried out using a method similar to that of Application Example 3. Figure 4 The solid electrolyte material Li obtained in Comparative Example 2 5.5 PS 4.5 Cl 1.5 Performance curve of lithium symmetric battery as electrolyte. Figure 3 By comparison, it was found that the solid electrolyte material Li 5.5 PS 4.5 Cl 1.5 As an electrolyte, it will produce obvious short-circuit phenomenon in lithium symmetric batteries within 100 hours of cycling.

[0082] The results show that the solid electrolyte composite material provided by the present invention has the characteristics of improving the cycle performance and safety performance of lithium-ion batteries, and can effectively alleviate problems such as short circuits of electrodes including metallic lithium during use in all-solid-state batteries.

[0083] Although the present invention has been described in detail above using general explanations, specific embodiments, and experiments, it will be apparent to those skilled in the art that modifications and improvements may be made based on the present invention. Therefore, such modifications and improvements, which do not depart from the spirit of the present invention, are intended to be within the scope of protection claimed herein.

Claims

1. A solid electrolyte composite material, characterized in that: It includes a compound containing a multi-amide group structure as shown in formula (1), and a sulfide solid electrolyte material; NH2-R-NH-[-OC-R-CO-NH-R-NH-] n -OC-R-COOH Formula (1) Wherein, R is a hydrocarbon group, a substituted hydrocarbon group, a hydrocarbon oxide group or an aromatic hydrocarbon group containing a benzene ring; n is greater than or equal to 10; The compound containing a multi-amide group structure represented by formula (1) is selected from a polybutylene adipamide polymer compound, a polybutylene phthalamide polymer compound, a polybutylene phthalamide polymer compound whose end groups are modified by fumigation with iodine vapor, and a polybutylene phthalamide polymer compound whose end groups are modified by fumigation with POCl3 vapor; The sulfide solid electrolyte material is one or more of the following inorganic fast ion conductors, including: sulfide solid electrolyte material argyrodite Li6PS5X and its derivatives, X = one or more of F, Cl, Br, I; Li 6+a Sb 1- a Si a S5I and its derivatives, 0.1≤a≤0.75; lithium germanium phosphorus sulfur phase Li 10 MP2S 12 and its derivatives, M = one or more of Si, Ge, Sn, Zn, Al; lithium phosphorus sulfur phase Li3PS4 phase and its derivatives; Li7P3S 11 phase and its derivatives; Li4MS4 phase and its derivatives, M = Si, Sn, Ge.

2. The solid electrolyte composite material according to claim 1, characterized in that R is a hydrocarbon group or a substituted hydrocarbon group having 1 to 10 carbon atoms; R is selected from any one of an alkyl group, an alkylene group, a haloalkyl group, a haloalkylene group, an alkenyl group, an alkenylene group, a haloalkenyl group, a haloalkenylene group, an aryl group, an arylene group, a haloaryl group, and a haloarylene group; the halogen is selected from fluorine, chlorine, bromine, and iodine; the halo is fully halogenated or partially halogenated; The compound containing a multi-amide group structure shown in formula (1) is modified with terminal groups and amide functional groups.

3. The solid electrolyte composite material according to claim 1, characterized in that The argyrodite Li6PS5X and its derivatives include: Li6PS5Cl; Li 6-x PS 5-x X 1+x , 0<x<0.7, X is one or more of F, Cl, Br, I; oxygen-doped Li 6-x PS 5-x-y X 1+x O y , 0<x<0.7, 0<y<1, X is one or more of F, Cl, Br, and I; The Li 6+a Sb 1-a Si a S5I and its derivatives contain Li 6+a Sb 1-a Si a S5I, 0.1≤a≤0.75; halogen-doped Li 6+ a Sb 1-a Si a S5X, 0.1≤a≤0.75, X is one or more of F, Cl, Br, I; oxygen-doped Li 6+a Sb 1-a Si a S 5- b XO b , 0.1≤a≤0.75, 0.1≤b≤1, X is one or more of F, Cl, Br, I; oxygen-doped Li 6+a+b Sb 1- a Si a S5X 1-b O b , 0.1≤a≤0.75, 0.01≤b≤0.2, X is one or more of F, Cl, Br, and I; The lithium germanium phosphorus sulfur phase Li 10 MP2S 12 and its derivatives include: Li 10 MP2S 12 , M=one or more of Si, Ge, Sn, Sb, Zn, Al; stoichiometric lithium germanium phosphorus sulfur phase; halogen-doped lithium germanium phosphorus sulfur phase; oxygen-doped lithium germanium phosphorus sulfur phase; The lithium phosphorus sulfur phase Li3PS4 phase and its derivatives include: Li3PS4; lithium phosphorus sulfur phase with a partial stoichiometric ratio; halogen-doped lithium phosphorus sulfur phase; lithium phosphorus sulfur phase doped with metal element M and oxygen-doped lithium phosphorus sulfur phase, M = Al, Mg, Si, Sn, Sb; The Li7P3S 11 Phases and their derivatives include: Li7P3S 11 ; Lithium phosphorus sulfur phase with a partial stoichiometric ratio; halogen-doped lithium phosphorus sulfur phase; lithium phosphorus sulfur phase doped with metal element M and oxygen-doped lithium phosphorus sulfur phase, M=Al, Mg, Si, Sn, Sb.

4. The solid electrolyte composite material according to any one of claims 1 to 3, characterized in that In the solid electrolyte composite material, the mass proportion of the compound containing a multi-amide group structure as shown in formula (1) is greater than 0 and less than or equal to 5%; In the solid electrolyte composite material, the mass ratio of the sulfide solid electrolyte material to the compound containing a multi-amide group structure as shown in formula (1) is 1:(0.01-0.025).

5. The solid electrolyte composite material according to claim 4, characterized in that: In the solid electrolyte composite material, the mass ratios of the sulfide solid electrolyte material and the compound containing a multi-amide group structure as shown in formula (1) are 1:0.01, 1:0.015, and 1:0.

025.

6. The method for preparing the solid electrolyte composite material according to any one of claims 1 to 5, characterized in that: include: The sulfide solid electrolyte material is compounded with a compound containing a multi-amide group structure as shown in formula (1); The specific compounding method adopts ball milling, grinding and heat treatment.

7. Use of the solid electrolyte composite material according to any one of claims 1 to 5 in in-situ protection of lithium negative electrodes.

8. A lithium negative electrode in-situ protection method, characterized in that: include: The solid electrolyte composite material according to any one of claims 1 to 5 is brought into contact with the surface of metallic lithium, and the surface of the metallic lithium negative electrode is in situ protected by an in-situ electrochemical deposition / removal method of metallic lithium.

9. The solid electrolyte composite material according to any one of claims 1 to 5 is used as any one of a solid electrolyte, a metal lithium negative electrode stabilizer, and an electrode-electrolyte interface modifier in a solid-state battery.

10. A lithium battery, characterized in that: include: The solid electrolyte composite material according to any one of claims 1 to 5; positive electrode; negative electrode; as well as an electrolyte interposed between the positive electrode and the negative electrode and comprising a sulfide solid electrolyte, an oxide solid electrolyte, a halide electrolyte, a nitride electrolyte, a polymer electrolyte, an organic electrolyte, or a combination thereof; The lithium battery is a lithium-ion battery, including all-solid batteries, semi-solid batteries and liquid batteries.

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