Organic-inorganic compound halide solid electrolyte material, preparation method thereof and battery

Abstract

The invention belongs to the technical field of batteries, and relates to an organic-inorganic compound halide solid electrolyte material, a preparation method thereof and a battery, the structural general formula of the solid electrolyte is (DaZc) m (at) (BdWe) n, D represents at least one of Sc, In, Y, Hf, Zr, Ta, Nb, Al, Mo, Ti, V, Ga, Sb, Cd, La, Ce, Pr, Sm, Nd, U, Eu, Er, Ho, Dm, Yb, Lu and Gy; z represents at least one of F, Cl, Br, I, O and S; b represents at least one of Li, Na, Ag, Cu, Cs, K, Mg and Ca; w is an organic acid ion. DaZc and BdWe are mixed in a water-free and oxygen-free environment, a solid-phase reaction is carried out, and the halide solid electrolyte is obtained. The halide solid-state electrolyte material provided by the invention can be simultaneously matched with an oxide positive electrode and a lithium metal negative electrode, is beneficial to solving the technical problem of poor matching property of an existing electrolyte material and the lithium metal negative electrode, and improves the energy density and the cycling stability of a solid-state battery.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of batteries, and particularly relates to an organic-inorganic combined halide solid electrolyte material and a preparation method thereof and a battery. BACKGROUND

[0002] With the transformation of global energy structure to low carbonization, the research and development of high energy density energy storage technology has become the key to breaking through the performance bottleneck of portable electronic devices, electric vehicles and large-scale energy storage systems. Lithium metal battery is considered as an ideal choice for the next generation of energy storage technology because the lithium metal negative electrode has a theoretical specific capacity of 3860 mAh / g and a standard electrode potential of -3.04 V, and is expected to achieve a leap in the energy density of energy storage devices. However, the interface stability problem of lithium metal negative electrode in electrolyte has always been the core challenge to its practical application.

[0003] Although the traditional liquid electrolyte has high ionic conductivity, it has the safety hazard of flammability and volatility, and lithium metal is easy to form dendrites in the liquid electrolyte, which leads to short circuit and even thermal runaway of the battery. The emergence of halide solid electrolyte provides a new direction to solve the above problems. Its solid state characteristics not only inhibit the growth of lithium dendrites, but also improve the safety and working temperature range of the battery. However, the comprehensive performance of the existing electrolyte material in the electrochemical window, stability and interface dynamics is still difficult to meet the practical application requirements of lithium metal battery. For example, some electrolytes will have problems such as interface phase decomposition and lithium dendrite penetration in long-term cycling, which leads to rapid capacity decay and even failure of the battery. Therefore, it is necessary to develop a halide electrolyte material to promote the practical application of lithium metal battery. SUMMARY

[0004] The purpose of the present application is to provide an organic-inorganic combined halide solid electrolyte material and a preparation method thereof and a battery, so as to solve the technical problem of poor matching of the existing electrolyte material with the lithium metal negative electrode and improve the cycle stability and safety performance of the battery.

[0005] To achieve the above purpose, the technical scheme is as follows:

[0006] According to the first aspect of the present application, a halide solid electrolyte material is provided,

[0007] including a halide solid electrolyte with a structural general formula of (D a Z c ) m @(B d W e ) n , wherein:

[0008] D represents one or more elements selected from Sc, In, Y, Hf, Zr, Ta, Nb, Al, Mo, Ti, V, Ga, Sb, Cd, La, Ce, Pr, Sm, Nd, U, Eu, Er, Ho, Dm, Yb, Lu, Gy;

[0009] Z represents one or more elements selected from F, Cl, Br, I, O, S;

[0010] B represents one or more elements selected from Li, Na, Ag, Cu, Cs, K, Mg, Ca;

[0011] W represents at least one anion selected from CH3O - , CH3O3 - , C2H5O - , C2H3O2 - , C2O4 2- , C4H4O6 2- , C7H5O2 - , F2NO4S2 - , CF3SO3 - , (F3C(SO2)N)2 - , (CF3SO2)2N - , (C2O4)2B - , F2(C2O4)B - , C4F9SO3 - , N(SO2C2F5)2 - , N(SO2CF3)(SO2C4F9) - ;

[0012] a and c respectively represent the number of atoms of D a Z c in the compound, and the number of atoms of Z element, d and e respectively represent the number of atoms of B d W e corresponding cation in the compound B element, and the number of W corresponding anion, m and n respectively represent the number of D a Z c and B d W e in the compound; wherein 0

[0013] The above technical solution provides a new organic-inorganic halide solid electrolyte material, which helps to improve the interfacial compatibility with the lithium metal negative electrode and form a stable interface. At the same time, the organic-inorganic halide solid electrolyte material has both high ionic conductivity and a wide electrochemical window, which can effectively inhibit the growth of lithium dendrites, improve the cycle stability and safety performance of the battery, and provide an important material foundation for the development of high-energy-density lithium metal solid-state batteries. This may be because the introduction of organic acid radical groups to obtain an organic-inorganic halide solid electrolyte can achieve rapid migration of lithium ions and help improve interfacial compatibility.

[0014] According to one embodiment of the present invention, the source of the D metal element includes at least one of anhydrous halides, halides with crystal water, and oxyhalides; when D = Zr or Hf, 0.1 <m≤4,0.1<n≤3.5。

[0015] According to one embodiment of the present invention, the halide solid electrolyte includes an amorphous phase, and the constituent elements or ions of the amorphous phase include D, Z, B and W.

[0016] Furthermore, the halide solid electrolyte may further include a crystalline phase, wherein the crystalline phase is located in an amorphous phase matrix; and the chemical composition of the crystalline phase includes BZ.

[0017] The organic-inorganic halide solid electrolyte material obtained by the above technical solution can be an amorphous structure, or precipitate a partial ionic salt crystal phase, which helps to increase the ion migration speed, has high ionic conductivity, a wide electrochemical window, is stable to the lithium metal negative electrode, and has good electrochemical performance.

[0018] According to one embodiment of the present invention, the organic-inorganic halide solid electrolyte material contains an additive, the additive is BRs; wherein R represents O 2- 、F - 、Cl - Br - , I - 、S 2- 、N 3- 、CO3 2- PO4 3- 、BF4 - 、ClO4 - 、AsF6 - PF6 - 、H2PO4 - 、SiO4 4- 、SO3 2- 、P2O7 4- 、SO4 2- 、SO3 2-at least one anion, s is the number of R ions, 0≤s<5.

[0019] In the process of preparing the organic-inorganic compound halide solid electrolyte material, the addition of appropriate amount of additives can further improve the ionic conductivity.

[0020] According to the second aspect of the application, a preparation method of a halide solid electrolyte material is provided, comprising the following steps: under the inert environment of no water and no oxygen, mixing D a Z c and B d W e , and carrying out solid phase reaction to obtain the halide solid electrolyte, the general structure formula of which is (D a Z c ) m (B d W e ) n ; wherein:

[0021] D represents one or more elements selected from Sc, In, Y, Hf, Zr, Ta, Nb, Al, Mo, Ti, V, Ga, Sb, Cd, La, Ce, Pr, Sm, Nd, U, Eu, Er, Ho, Dm, Yb, Lu, Gy;

[0022] Z represents one or more elements selected from F, Cl, Br, I, O, S;

[0023] B represents one or more elements selected from Li, Na, Ag, Cu, Cs, K, Mg, Ca;

[0024] W represents at least one anion selected from CH3O - , CH3O3 - , C2H5O - , C2H3O2 - , C2O4 2- , C4H4O6 2- , C7H5O2 - , F2NO4S2 - , CF3SO3 - , (F3C(SO2)N)2 - , (CF3SO2)2N - , (C2O4)2B - , F2(C2O4)B - , C4F9SO3 - , N(SO2C2F5)2 - , N(SO2CF3)(SO2C4F9) - .

[0025] a and c represent D respectively a Z c The atomic number of D element and the atomic number of Z element in the compound, d and e represent B respectively d W e The atomic number of B element corresponding cation in the compound and the number of W corresponding anion, m and n represent D respectively a Z c and B d W e The amount of substance of the compound; wherein, 0

[0026] Further, in the inert environment without water and oxygen, D a Z c and B d W e are mixed, and a simple mechanical ball milling method is used to make D a Z c and B d W e under the solid phase reaction of mechanical chemical conditions.

[0027] The above technical solution has strong operability, few steps, short preparation period, avoids high energy consumption of high temperature sintering, and has application advantages of large-scale production.

[0028] Further, the solid phase reaction of D a Z c and B d W e after mixing is realized by mechanical ball milling, and the diameter of the ball milling beads is 1mm-10mm; the mass ratio of the ball milling beads to the raw materials is 10-100:1.2.

[0029] Preferably, the diameter of the ball milling beads is 1mm-4mm; and the mass ratio of the ball milling beads to the raw materials is 1-2-16-20.

[0030] Preferably, the parameter conditions of the mechanical ball milling are: the ball milling time is 0.5h-120h; and the ball milling rotation speed is 200rpm-700rpm.

[0031] Preferably, the parameter conditions of the mechanical ball milling are: the ball milling time is 18h-28h; and the ball milling rotation speed is 500rpm-600rpm.

[0032] According to an embodiment of the present application, in the preparation method of the halide solid electrolyte material, an additive is also added in the process of mixing D a Z c and B d W e , so that Da Z c 、B d W e solid phase reaction with an additive, the additive being BRs; wherein R represents at least one of O 2- 、F - 、Cl - 、Br - 、I - 、S 2- 、N 3- 、CO3 2- 、PO4 3- 、BF4 - 、ClO4 - 、AsF6 - 、PF6 - 、H2PO4 - 、SiO4 4- 、SO3 2- 、P2O7 4- 、SO4 2- 、SO3 2- , s is the number of R ions, 0≤s<5.

[0033] According to a third aspect of the present application, a battery is provided, comprising the organic-inorganic compound halide solid-state electrolyte material described above, or the organic-inorganic compound halide solid-state electrolyte material obtained by the preparation method described above. The battery is a solid-state battery or a low-pressure battery. The battery types include lithium ion batteries, sodium ion batteries, potassium ion batteries, silver ion batteries, calcium ion batteries, magnesium ion batteries, or copper ion batteries.

[0034] Compared with the prior art, the present application at least includes the following beneficial effects:

[0035] 1. The present application breaks through to develop an organic-inorganic compound halide solid-state electrolyte material, which can directly match the lithium metal negative electrode, fundamentally solves the interface compatibility problem, and lays a key material foundation for the practical application of lithium metal negative electrode in solid-state batteries; solves the problem that the lithium metal negative electrode cannot be directly applied for charge and discharge cycling in existing solid-state batteries due to the insufficient stability of halide electrolyte to lithium metal.

[0036] 2. The electrolyte provided by the present application has a lithium ion conductivity as high as 0.86 mS cm -1 , which can realize the rapid migration of lithium ions and effectively reduce the internal resistance of the battery. The solid-state battery assembled by using the electrolyte can directly adapt to the lithium metal negative electrode, avoiding the safety hazards of traditional liquid electrolytes, and is expected to significantly improve the energy density of the battery and meet the development needs of high-energy storage equipment.

[0037] 3、The preparation method of the organic-inorganic combined halide solid-state electrolyte of the present application adopts a one-step synthesis process, which is simple in operation steps, low in energy consumption, and widely applicable. This efficient synthesis path not only reduces the production difficulty, but also provides a feasible solution for large-scale production, which meets the requirements of cost control and process stability for industrial production.

[0038] 4、The organic-inorganic combined halide solid-state electrolyte material provided by the present application has significant component adjustability, and the performance can be optimized by adjusting the raw material ratio. Moreover, the raw materials are low in price, which reduces the material cost from the source, so that the material has high performance and economic feasibility, and has a wide market application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0039] The drawings described herein are used to provide further understanding of the embodiments of the present application, constitute a part of the present application, and do not constitute a limitation on the embodiments of the present application. In the drawings:

[0040] Figure 1 The X-ray diffraction pattern of the organic-inorganic combined halide solid-state electrolyte material of the present application example 1;

[0041] Figure 2 The electron microscope pattern of the organic-inorganic combined halide solid-state electrolyte material of the present application example 7;

[0042] Figure 3 The long cycle test result graph of the lithium-lithium symmetric battery of the present application example 1;

[0043] Figure 4 The long cycle test result graph of the lithium-lithium symmetric battery of the present application example 2;

[0044] Figure 5 The electrochemical performance graph of the lithium cobaltate / lithium metal solid-state battery obtained in the present application example 3 under room temperature conditions;

[0045] Figure 6 The electrochemical performance graph of the NCM811 / lithium metal solid-state battery obtained in the present application example 4 under room temperature conditions. DETAILED DESCRIPTION

[0046] The present application will be described in detail below with reference to the drawings and in combination with the embodiments. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0047] The following detailed description is merely exemplary in nature and is intended to provide further detail on the present application. All the technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs unless otherwise specifically defined herein. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the example embodiments according to the present application.

[0048] Example 1

[0049] (I) Preparation of organic-inorganic compound halide solid electrolyte material

[0050] S1. Under anhydrous and anaerobic inert conditions, Li2C2O4 and ZrCl4 were ground in a mortar for 30 min to fully mix them, obtaining a mixed powder; the molar ratio of Li2C2O4 to ZrCl4 was 1:1.5.

[0051] S2. The mixed powder obtained in step S1 was transferred to a zirconium oxide ball mill jar, and ball milling beads were added to the mixed powder, keeping the ball mill jar sealed, and mechanical ball milling was carried out on a planetary ball mill, obtaining a halide solid electrolyte; the ball milling time was 24 h, and the ball milling speed was 500 rpm. The mass ratio of the mixed powder to the ball milling beads was 1:16; wherein the ball milling beads were selected in two specifications of 1 mm in diameter and 3 mm in diameter, and the mass ratio of the two different specifications of ball milling beads was 1:1.

[0052] The structural formula of the organic-inorganic compound halide solid electrolyte material obtained according to the above method is: Li2C2O4@ZrCl4. The X-ray diffraction pattern of the halide solid electrolyte material obtained in this embodiment is shown in FIG. 1. Figure 1 .

[0053] Example 2

[0054] The difference between this embodiment and Example 1 is that:

[0055] In the preparation process of the organic-inorganic compound halide solid electrolyte material, ZrCl4 in step S1 is replaced by AlCl3 of the same physical mass, that is, the molar ratio of Li2C2O4 to AlCl3 is 1:1.5; and the structural formula of the organic-inorganic compound halide solid electrolyte material obtained is: Li2C2O4@AlCl3.

[0056] The other steps and conditions are the same.

[0057] Example 3

[0058] The difference between this embodiment and Example 1 is that:

[0059] In the preparation process of the organic-inorganic combined halide solid electrolyte material, in step S1, ZrCl4 is replaced by TaCl5 with the same physical mass, that is, the molar ratio of Li2C2O4 to TaCl5 is 1:1.5; and the structural formula of the obtained organic-inorganic combined halide solid electrolyte material is Li2C2O4@TaCl5.

[0060] Other steps and conditions are the same.

[0061] Example 4

[0062] The difference between this embodiment and Example 1 is that:

[0063] In the preparation process of the organic-inorganic combined halide solid electrolyte material, in step S1, Li2C2O4 is replaced by LiCOOH, and ZrCl4 is replaced by HfCl4, and the molar ratio of LiCOOH to HfCl4 is 1:2. In step S2, the mass ratio of the mixed powder to the ball milling beads is 1.1:20; the ball milling time is 20 h, and the ball milling speed is 500 rpm; the ball milling beads are selected to have two specifications of 2 mm in diameter and 4 mm in diameter, and the mass ratio of the ball milling beads with a diameter of 2 mm to the ball milling beads with a diameter of 4 mm is 1:3.

[0064] The structural formula of the obtained organic-inorganic combined halide solid electrolyte material is LiCOOH@HfCl4.

[0065] Other steps and conditions are the same.

[0066] Example 5

[0067] The difference between this embodiment and Example 1 is that:

[0068] In the preparation process of the organic-inorganic combined halide solid electrolyte material, in step S1, Li2C2O4 is replaced by C7H5LiO2, and ZrCl4 is replaced by HfCl4, and the molar ratio of C7H5LiO2 to HfCl4 is 1:2. In step S2, the mass ratio of the mixed powder to the ball milling beads is 1.1:20; the ball milling time is 20 h, and the ball milling speed is 500 rpm; the ball milling beads are selected to have two specifications of 2 mm in diameter and 4 mm in diameter, and the mass ratio of the ball milling beads with a diameter of 2 mm to the ball milling beads with a diameter of 4 mm is 1:3.

[0069] The structural formula of the obtained organic-inorganic combined halide solid electrolyte material is C7H5LiO2@HfCl4.

[0070] Other steps and conditions are the same.

[0071] Example 6

[0072] The difference between this embodiment and embodiment 1 is that:

[0073] In the preparation process of the organic-inorganic combined halide solid electrolyte material, in step S1, Li2C2O4 is replaced by C4H4Li2O6, and ZrCl4 is replaced by HfCl4. The mass ratio of C4H4Li2O6 to HfCl4 is 1:2. In step S2, the mass ratio of the mixed powder to the ball milling beads is 1.1:20; the ball milling time is 20 h, the ball milling speed is 500 rpm; the ball milling beads are selected in two specifications of 2 mm in diameter and 4 mm in diameter, and the mass ratio of the ball milling beads of 2 mm in diameter to the ball milling beads of 4 mm in diameter is 1:3.

[0074] The structural formula of the obtained organic-inorganic combined halide solid electrolyte material is C4H4Li2O6@HfCl4.

[0075] The other steps and conditions are the same.

[0076] Embodiment 7

[0077] The difference between this embodiment and embodiment 1 is that:

[0078] In the preparation process of the organic-inorganic combined halide solid electrolyte material, in step S1, Li2C2O4 is replaced by C4H4Li2O6, and ZrCl4 is replaced by HfCl4. The mass ratio of C4H4Li2O6 to HfCl4 is 1:2. In step S2, the mass ratio of the mixed powder to the ball milling beads is 1.1:20; the ball milling time is 20 h, the ball milling speed is 500 rpm; the ball milling beads are selected in two specifications of 2 mm in diameter and 4 mm in diameter, and the mass ratio of the ball milling beads of 2 mm in diameter to the ball milling beads of 4 mm in diameter is 1:3.

[0079] The structural formula of the obtained organic-inorganic combined halide solid electrolyte material is C4H4Li2O6@HfCl4.

[0080] The other steps and conditions are the same.

[0081] The microstructure information of the organic-inorganic combined halide solid electrolyte material synthesized in embodiment 7 is characterized by using a high-resolution cryogenic transmission electron microscope, as shown in FIG. 6. Figure 2 As shown in FIG. 6, most of the halide solid electrolyte material is in an amorphous state, and a small amount of LiCl crystal phase structure is embedded in the amorphous matrix, indicating that the electrolyte material belongs to a coexistence state of crystal phase and amorphous phase.

[0082] Embodiment 8

[0083] The difference between this embodiment and embodiment 1 is that:

[0084] In the preparation process of the organic-inorganic combined halide solid electrolyte material, in step S1, Li2C2O4 is replaced by LiCOOH, ZrCl4 is replaced by AlCl3, and the amount-of-substance ratio of LiCOOH to AlCl3 is 1:2. In step S2, the mass ratio of the mixed powder to the ball milling beads is 1.1:20; the ball milling time is 20 h, the ball milling speed is 500 rpm; the ball milling beads are selected to have two specifications of 2 mm in diameter and 4 mm in diameter, and the mass ratio of the ball milling beads with a diameter of 2 mm to the ball milling beads with a diameter of 4 mm is 1:3.

[0085] The structural formula of the obtained organic-inorganic combined halide solid electrolyte material is LiCOOH@AlCl3.

[0086] The other steps and conditions are the same.

[0087] Example 9

[0088] The difference between this example and Example 1 is that:

[0089] In the preparation process of the organic-inorganic combined halide solid electrolyte material, in step S1, Li2C2O4 is replaced by LiCOOH, ZrCl4 is replaced by HfCl4, and the amount-of-substance ratio of LiCOOH to HfCl4 is 1:2; and Li3PO4 is added as an additive, and the amount-of-substance ratio of LiCOOH to Li3PO4 is 1:1. In step S2, the mass ratio of the mixed powder to the ball milling beads is 1:16; the ball milling time is 18 h, the ball milling speed is 500 rpm; the ball milling beads are selected to have two specifications of 2 mm in diameter and 4 mm in diameter, and the mass ratio of the ball milling beads with a diameter of 2 mm to the ball milling beads with a diameter of 4 mm is 1:7.

[0090] The structural formula of the obtained organic-inorganic combined halide solid electrolyte material is LiCOOH-Li3PO4@HfCl4.

[0091] The other steps and conditions are the same.

[0092] Example 10

[0093] The difference between this example and Example 1 is that:

[0094] In the preparation process of the organic-inorganic compound halide solid-state electrolyte material, in step S1, Li2C2O4 and ZrCl4 are used to prepare a mixed powder, Li4SiO4 is added as an additive, the amount-of-substance ratio of Li2C2O4 to ZrCl4 is 1:2, and the amount-of-substance ratio of LiCOOH to Li4SiO4 is 1:1. In step S2, the mass ratio of the mixed powder to the ball milling beads is 1:16; the ball milling time is 18 h, the ball milling speed is 500 rpm; the ball milling beads are selected in two specifications of a diameter of 2 mm and a diameter of 4 mm, and the mass ratio of the ball milling beads with a diameter of 2 mm to the ball milling beads with a diameter of 4 mm is 1:7.

[0095] The structural formula of the obtained organic-inorganic compound halide solid-state electrolyte material is Li2C2O4-Li4SiO4@ZrCl4.

[0096] The other steps and conditions are the same.

[0097] Example 11

[0098] The difference between this example and Example 1 is that:

[0099] In the preparation process of the organic-inorganic compound halide solid-state electrolyte material, in step S1, ZrCl4 is replaced by AlCl3, the amount-of-substance ratio of Li2C2O4 to AlCl3 is 1:2; and Li2CO3 is added as an additive, the amount-of-substance ratio of Li2C2O4 to Li2CO3 is 1:1. In step S2, the mass ratio of the mixed powder to the ball milling beads is 1:16; the ball milling time is 18 h, the ball milling speed is 500 rpm; the ball milling beads are selected in two specifications of a diameter of 2 mm and a diameter of 4 mm, and the mass ratio of the ball milling beads with a diameter of 2 mm to the ball milling beads with a diameter of 4 mm is 1:7.

[0100] The structural formula of the obtained organic-inorganic compound halide solid-state electrolyte material is Li2C2O4-Li2CO3@AlCl3.

[0101] The other steps and conditions are the same.

[0102] Comparative Example 1

[0103] (I) Preparation of the halide solid-state electrolyte material

[0104] S1. Under anhydrous and anaerobic inert conditions, LiCl and ZrCl4 were placed in a mortar and ground for 30 min to fully mix them, to obtain a mixed powder; the amount-of-substance ratio of LiCl to ZrCl4 was 2:1.

[0105] S2. The mixed powder is transferred to a zirconium oxide ball mill tank, and ball milling beads are added to the mixed powder. The ball mill tank is kept sealed, and mechanical ball milling is performed on a planetary ball mill to obtain a halide solid-state electrolyte. The ball milling time is 20 h, and the ball milling speed is 500 rpm. The mass ratio of the mixed powder to the ball milling beads is 1:16. The ball milling beads are selected to have a diameter of 1 mm and a diameter of 3 mm, and the mass ratio of the two different sizes of ball milling beads is 1:1.

[0106] The structural formula of the organic-inorganic compound halide solid-state electrolyte material obtained according to the above method is Li2ZrCl6.

[0107] Comparative Example 2

[0108] The difference between the present comparative example and Comparative Example 1 is that:

[0109] In the preparation process of the halide solid-state electrolyte material, ZrCl4 is replaced by an equal amount of HfCl4 in step S1, that is, the amount-of-substance ratio of LiCl to HfCl4 is 2:1. The structural formula of the organic-inorganic compound halide solid-state electrolyte material obtained is Li2HfCl6.

[0110] The other steps and conditions are the same.

[0111] Application Example 1

[0112] The organic-inorganic compound halide solid-state electrolyte material of Example 1 is used to assemble a lithium-lithium symmetric battery. Specifically, 100 mg of the halide solid-state electrolyte Li2C2O4@ZrCl4 of Example 1 is weighed, 300 MPa pressure is applied for 3 min to obtain a halide solid-state electrolyte disc with a diameter of 10 mm, then 10 mm lithium metal discs are added to the positive and negative electrodes, respectively, and the electrolyte disc and the lithium metal of the positive and negative electrodes are integrated under a pressure of 10 MPa, and then placed in a mold battery shell to obtain a lithium-lithium symmetric battery.

[0113] This symmetric battery only uses a single layer of halide solid-state electrolyte, does not add any other type of solid-state electrolyte, and removes the operation of adding a sulfide solid-state electrolyte separator layer on the lithium metal negative electrode side in the conventional assembly method.

[0114] Application Example 2

[0115] The halide solid-state electrolyte Li2ZrCl6 of Comparative Example 1 is used to make a halide solid-state electrolyte disc according to the method of Application Example 1, and a lithium-lithium symmetric battery is assembled. This symmetric battery only uses a single layer of halide solid-state electrolyte, does not add any other type of solid-state electrolyte, and removes the operation of adding a sulfide solid-state electrolyte separator layer on the lithium metal negative electrode side in the conventional assembly method.

[0116] Application Example 3

[0117] A solid-state battery was assembled using the organic-inorganic composite halide solid electrolyte material of Example 1. The solid-state battery of this application example only uses a single layer of halide solid electrolyte, eliminating the operation of adding a sulfide halide solid electrolyte separator on the lithium metal negative electrode side in the conventional assembly method, and achieving a single layer of organic-inorganic composite halide solid electrolyte to obtain a safe and stable battery cycle.

[0118] Positive electrode material: A positive electrode / electrolyte composite material was prepared, using lithium cobaltate as the positive electrode material; lithium cobaltate, the halide solid electrolyte Li2C2O4@ZrCl4 in Example 1, and conductive carbon were weighed in a mass ratio of 70:29:1, respectively, and the three were ground in a glove box for 20 min to achieve thorough mixing. The resulting mixed powder was used as the positive electrode composite material.

[0119] The specific battery assembly method was as follows: 100 mg of the Li2C2O4@ZrCl4 halide solid electrolyte of Example 1 was placed in a solid-state battery mold with a diameter of 10 mm, and was pressurized at 100 MPa for 1 min to obtain a halide solid electrolyte disc. Then, 10 mg of the positive electrode composite material was added to the positive electrode side, and the electrolyte disc and the positive electrode material were integrated into one body at a pressure of 350 MPa. Finally, a lithium metal disc with a diameter of 10 mm was placed on the negative electrode side, and the mold battery shell was tightened with all screws at low pressure to obtain a lithium cobaltate / lithium metal solid-state battery.

[0120] Application Example 4

[0121] The difference between this application example and Application Example 3 is as follows:

[0122] In the preparation of the positive electrode / electrolyte composite material, NCM811 was used as the positive electrode material, and the mass ratio of NCM811, the organic-inorganic composite halide solid electrolyte Li2C2O4@ZrCl4 in Example 1, and conductive carbon was 70:29:1. An NCM811 / lithium metal solid-state battery was obtained.

[0123] The other steps and conditions were the same.

[0124] Test Example

[0125] (I) Ion conductivity test

[0126] First, 200 mg of each of the organic-inorganic composite halide solid electrolyte materials obtained in Examples 1-7 was placed in a mold battery with a diameter of 10 mm and was pressed into an electrolyte disc with a diameter of 10 mm at a pressure of 350 MPa in an argon atmosphere free of water and oxygen. The area of the obtained electrolyte disc was S = 0.785 cm 2The thickness of the electrolyte wafer was measured using a high-precision vernier caliper, and was denoted as L.

[0127] The electrolyte wafers obtained in Examples 1-7 and Comparative Examples 1-2 were subjected to conventional ionic conductivity tests at a temperature of 25°C, and the calculation formula was σ = L / (R*S), wherein L was the thickness of the solid electrolyte after cold pressing, and R was the impedance of the electrolyte material measured by an alternating current impedance method. The ionic conductivity test results of the electrolyte wafers obtained in Examples 1-7 and Comparative Example 2 are shown in Table 1.

[0128] Table 1: Ionic conductivity test results of the electrolyte wafers obtained in the examples and comparative examples

[0129] Serial number Ionic conductivity (mS / cm) Example 1 0.86 Example 2 0.34 Example 3 0.42 Example 4 0.038 Example 5 0.45 Example 6 0.78 Example 7 0.62 Example 8 0.031 Example 9 1.3 Example 10 1.21 Example 11 0.9 Comparative Example 1 0.01 Comparative Example 2 0.03

[0130] Referring to the data in Table 1, in the preparation of the organic-inorganic combined halide solid-state electrolyte in Examples 1-8, the molar ratio of lithium ions in the lithium salt to the inorganic halide was lower than that in Comparative Example 1 and Comparative Example 2; however, the ionic conductivity test results of Examples 1-8 were 85 times, 33 times, 41 times, 2.76 times, 44.3 times, 77 times, 62 times and 2.2 times higher than those of Comparative Example 1, and 27.67 times, 10.33 times, 13 times, 25.33%, 14.1 times, 25 times, 19.67 times and 33.33% higher than those of Comparative Example 2, respectively. It can be seen that, compared with the halide solid-state electrolyte material without organic acid root groups, the organic-inorganic combined halide solid-state electrolyte material obtained by solid-phase reaction of organic lithium salt and different inorganic halides has higher ionic conductivity.

[0131] Further, in combination with the ionic conductivity test results of Examples 1 and Comparative Example 1, and the ionic conductivity test results of Examples 4-6 and Comparative Example 2, in the case of a relatively reduced molar ratio of lithium ions in the lithium salt to the inorganic halide (ZrCl4), the ionic conductivity of Example 1 was 85 times higher than that of Comparative Example 1; in the case of a relatively reduced molar ratio of lithium ions in the lithium salt to the inorganic halide (HfCl4), the ionic conductivities of Examples 4-6 were 25%, 14.1 times and 25 times higher than those of Comparative Example 2, respectively; it can be inferred that, compared with the halide solid-state electrolyte material without organic acid root groups, the ionic conductivity of the organic-inorganic combined halide solid-state electrolyte material is greatly improved, and it can be seen that the organic-inorganic combined halide solid-state electrolyte material has significantly improved stability to lithium metal, and can effectively reduce the internal resistance of the battery.

[0132] In combination with the ion conductivity test results of Comparative Example 1, in the case of a relatively reduced molar ratio of lithium ions to inorganic halides in lithium salts, the ion conductivities of Examples 1-3 are 85 times, 33 times and 41 times, respectively, higher than that of Comparative Example 1. In addition, in combination with the ion conductivity test results of Comparative Example 2, it can be considered that the type of inorganic halides has an effect on improving the ion conductivity of the organic-inorganic combined halide solid-state electrolyte, but the effect of the type of organic lithium on improving the ion conductivity of the organic-inorganic combined halide solid-state electrolyte is much greater.

[0133] In combination with the ion conductivity test results of Comparative Example 9 and Example 4, Example 10 and Example 3, and Example 11 and Example 2, respectively, the ion conductivity of Example 9 is 33.57 times higher than that of Example 4, the ion conductivity of Example 10 is 1.88 times higher than that of Example 3, and the ion conductivity of Example 11 is 1.65 times higher than that of Example 2. It can be seen that, in the process of preparing the organic-inorganic combined halide solid-state electrolyte material, the addition of an appropriate amount of additive can further improve the ion conductivity.

[0134] It can thus be considered that, in the process of preparing the organic-inorganic combined halide solid-state electrolyte material, the introduction of an organic acid group into the organic-inorganic combined halide solid-state electrolyte can achieve fast migration of lithium ions and effectively reduce the internal resistance of the battery.

[0135] (ii) Long cycle test

[0136] At room temperature (25°C), the lithium-lithium symmetric batteries assembled using Application Example 1 and Application Example 2 were subjected to a long cycle test using a blue cell test system, and the test conditions were set to 0.1 mA / cm 2 and 0.1 mAh / cm 2 . The test results are shown in Figure 3 and Figure 4 , respectively. The cycle voltage curve of the lithium-lithium symmetric battery of Application Example 2 increases with increasing cycle time, and the response voltage increases under the condition of constant current density until it reaches the cutoff voltage and stops after 22 h, indicating that the internal continuous interface reaction causes a change in resistance, showing serious instability to lithium metal. In contrast, the lithium-lithium symmetric battery of Application Example 1 can achieve stable electrochemical cycling for more than 550 hours, indicating that the organic-inorganic combined halide solid-state electrolyte of this application example exhibits a long-term stable solid-state electrolyte / lithium metal interface, which is beneficial to improving the energy density of the solid-state battery.

[0137] (iii) Charge-discharge cycle test

[0138] At room temperature (25℃), the lithium cobalt oxide / lithium metal solid-state battery obtained in Application Example 3 was charged at a current density of 0.2C until the voltage reached 4.3V. Then, the lithium cobalt oxide / lithium metal solid-state battery obtained in Application Example 3 was discharged at the same current density until the voltage reached 2.5V. The charge-discharge cycle curve is shown in Figure 5 , and the results show that the lithium cobalt oxide / lithium metal solid-state battery containing the halide solid-state electrolyte material obtained in Example 1 has excellent stability to lithium, and the assembled lithium metal solid-state battery is stably cycled for more than 60 weeks, and the coulombic efficiency is greater than 99%.

[0139] At room temperature (25℃), the NCM811 / lithium metal solid-state battery obtained in Application Example 4 was charged at a current density of 0.2C until the voltage reached 4.3V. Then, the NCM811 / lithium metal solid-state battery obtained in Application Example 4 was discharged at the same current density until the voltage reached 2.5V. The charge-discharge cycle curve is shown in Figure 6 , the NCM811 / lithium metal solid-state battery obtained in Application Example 4 only uses a single layer of halide solid-state electrolyte, and simultaneously realizes stability to the oxide positive electrode and the lithium metal negative electrode. The NCM811 / lithium metal solid-state battery undergoes more than 100 weeks of long cycle, still maintains a capacity retention rate of greater than 80%, and exhibits the practical prospect of the organic-inorganic halide solid-state electrolyte.

[0140] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application and not to limit it, although the present application has been described in detail with reference to the above examples, those skilled in the art should understand that: the specific embodiments of the present application can still be modified or replaced by equivalents without departing from the spirit and scope of the present application, any modification or equivalent replacement thereof should be covered within the protection scope of the claims of the present application.

Claims

1. An organic-inorganic halide solid electrolyte material, characterized in that: Including the general structural formula (D a Z c ) m @(B d W e ) n A halide solid electrolyte, wherein: D represents one or more elements selected from the group consisting of Sc, In, Y, Hf, Zr, Ta, Nb, Al, Mo, Ti, V, Ga, Sb, Cd, La, Ce, Pr, Sm, Nd, U, Eu, Er, Ho, Dm, Yb, Lu, and Gy; Z represents one or more elements selected from F, Cl, Br, I, O, and S; B represents one or more elements selected from Li, Na, Ag, Cu, Cs, K, Mg, and Ca; W stands for CH3O - 、CH3O3 - 、C2H5O - 、C2H3O2 - 、C2O4 2- 、C4H4O6 2- 、C7H5O2 - 、F2NO4S2 - CF3SO3 - 、(F3C(SO2)N)2 - 、(CF3SO2)2N - 、(C2O4)2B - 、F2(C2O4)B - 、C4F9SO3 - 、N(SO2C2F5)2 - 、N(SO2CF3)(SO2C4F9) - At least one anion in a and c respectively represent D a Z c The number of atoms of element D and the number of atoms of element Z in the compound, d and e respectively represent B d W e The number of atoms of the cation corresponding to element B and the number of anions corresponding to W in the compound, m and n respectively represent D a Z c and B d W e The amount of substance of the compound; wherein, 0 < a, 0 < c ≤ 6, d is 1 or 2, e is 1 or 2, 0.1 < m ≤ 5, 0.1 < n ≤ 6.

2. The organic-inorganic halide solid electrolyte material according to claim 1, characterized in that: The source of the D metal element includes at least one of anhydrous halides, halides with crystal water, and halogen oxides; when D = Zr or Hf, 0.1 <m≤4,0.1<n≤3.5。 3. The organic-inorganic halide solid electrolyte material according to claim 1, characterized in that: The halide solid electrolyte includes an amorphous phase, and constituent elements or ions of the amorphous phase include D, Z, B, and W.

4. The organic-inorganic halide solid electrolyte material according to claim 1, characterized in that: The halide solid electrolyte further comprises a crystalline phase, the crystalline phase is in an amorphous phase matrix, and the chemical composition of the crystalline phase includes BZ.

5. The organic-inorganic halide solid electrolyte material according to claim 1, characterized in that: The organic-inorganic halide solid electrolyte material further comprises an additive, which is BRs; wherein R represents O 2- 、F - 、Cl - Br - , I - 、S 2- 、N 3- 、CO3 2- PO4 3- 、BF4 - 、ClO4 - 、AsF6 - PF6 - 、H2PO4 - 、SiO4 4- 、SO3 2- 、P2O7 4- 、SO4 2- 、SO3 2- At least one anion in, s is the number of R ions, 0≤s<5.

6. A method for preparing an organic-inorganic halide solid electrolyte material, characterized in that: The following steps are involved: In an anhydrous and oxygen-free environment, D a Z c With B d W e Mix and undergo solid phase reaction to obtain a halide solid electrolyte, the general structural formula of which is (D a Z c ) m @(B d W e ) n ;in: D represents one or more elements selected from the group consisting of Sc, In, Y, Hf, Zr, Ta, Nb, Al, Mo, Ti, V, Ga, Sb, Cd, La, Ce, Pr, Sm, Nd, U, Eu, Er, Ho, Dm, Yb, Lu, and Gy; Z represents one or more elements selected from F, Cl, Br, I, O, and S; B represents one or more elements selected from Li, Na, Ag, Cu, Cs, K, Mg, and Ca; W stands for CH3O - 、CH3O3 - 、C2H5O - 、C2H3O2 - 、C2O4 2- 、C4H4O6 2- 、C7H5O2 - 、F2NO4S2 - CF3SO3 - 、(F3C(SO2)N)2 - 、(CF3SO2)2N - 、(C2O4)2B - 、F2(C2O4)B - 、C4F9SO3 - 、N(SO2C2F5)2 - 、N(SO2CF3)(SO2C4F9) - At least one anion in a and c respectively represent D a Z c The number of atoms of element D and the number of atoms of element Z in the compound, d and e respectively represent B d W e The number of atoms of the cation corresponding to element B and the number of anions corresponding to W in the compound, m and n respectively represent D a Z c and B d W e The amount of substance of the compound; wherein, 0 < a, 0 < c ≤ 6, d is 1 or 2, e is 1 or 2, 0.1 < m ≤ 5, 0.1 < n ≤ 6.

7. The method for preparing the organic-inorganic halide solid electrolyte material according to claim 6, characterized in that: Mechanical ball milling is used to achieve D a Z c With B d W e For the solid phase reaction, the diameter of the ball milling beads is 1 mm to 10 mm; the mass ratio of the ball milling beads to the raw materials is 10-100:1.

2.

8. The method for preparing the organic-inorganic halide solid electrolyte material according to claim 7, characterized in that: The parameters of the mechanical ball milling are as follows: the ball milling time is 0.5h-120h; the ball milling speed is 200rpm-700rpm.

9. The method for preparing the organic-inorganic halide solid electrolyte material according to claim 6, characterized in that: In D a Z c With B d W e During the mixing process, an additive is added, wherein the additive is BRs; wherein R represents O 2- 、F - 、Cl - Br - , I - 、S 2- 、N 3- 、CO3 2- PO4 3- 、BF4 - 、ClO4 - 、AsF6 - PF6 - 、H2PO4 - 、SiO4 4- 、SO3 2- 、P2O7 4- 、SO4 2- 、SO3 2- At least one anion in, s is the number of R ions, 0≤s<5.

10. A battery, characterized in that: An organic-inorganic halide solid electrolyte material comprising the organic-inorganic halide solid electrolyte material according to any one of claims 1 to 5 or an organic-inorganic halide solid electrolyte material obtained by the preparation method of the organic-inorganic halide solid electrolyte material according to any one of claims 6 to 9.

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