Carbon-based solid electrolyte as well as preparation method and application thereof

Abstract

The invention relates to the technical field of batteries, in particular to a carbon-based solid electrolyte and a preparation method thereof, a pole piece and an all-solid-state battery, and the general formula of the carbon-based solid electrolyte is MaCbXxYy (1), wherein M is selected from at least one of metal elements in the IA family, X is selected from at least one of halogen and negative monovalent groups, and Y is selected from at least one of non-metal elements in the IVA family and negative divalent groups; 1 < = a < = 6, 0.5 < = b < = 2, 0lt; 0 < = y < = 6. The carbon-based solid electrolyte provided by the invention has relatively high ionic conductivity and excellent deformability, the element cost is low, and the key problem of solid-solid interface contact in an all-solid electrolyte can be solved, so that the electrochemical performance of a battery is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and particularly to a carbon-based solid electrolyte, a preparation method of a carbon-based solid electrolyte, an electrode sheet containing a carbon-based solid electrolyte, a film containing a carbon-based solid electrolyte, and a all-solid-state battery. Background Art

[0002] All-solid-state batteries are considered to be a promising new generation of energy storage devices due to their good safety, high energy density, and wide application range. Different from the direct and sufficient contact between rigid cathode material particles and liquid electrolyte in current mainstream commercial lithium-ion batteries, in all-solid-state batteries, it is the solid-solid contact between rigid oxide cathode material particles and solid electrolyte. This contact method often leads to a large interfacial resistance. An ideal solid electrolyte material should not only have excellent electrochemical performance and low commercial application cost, but also have good plastic toughness to enhance the contact with electrode materials, thereby offsetting to a certain extent the volume deformation generated by electrode materials during charge and discharge and reducing the interfacial impedance.

[0003] Currently, the mainstream inorganic solid electrolyte materials include oxide solid electrolytes, sulfide solid electrolytes, and halide solid electrolytes. There are products with relatively high ionic conductivity in their systems. However, for oxide solid electrolytes, they generally have a relatively large hardness, resulting in poor interfacial contact with rigid electrode materials; while for sulfide and halide solid electrolytes, although they have a relatively small hardness, due to most of them containing various metal elements such as precious metals, heavy metals, and rare metals, their material costs are relatively high. In addition, some metal elements have limited reserves and are difficult to further expand production. Moreover, the requirements for their synthesis environment are also relatively high, further increasing the overall cost of all-solid-state lithium batteries.

[0004] Therefore, the design and development of new solid electrolyte materials with high ionic conductivity, excellent plastic toughness, and low cost play a great role in promoting the development of all-solid-state batteries. Summary of the Invention

[0005] The purpose of the present invention is to overcome the above technical problems and provide a carbon-based solid electrolyte, a preparation method of a carbon-based solid electrolyte, an electrode sheet containing a carbon-based solid electrolyte, a film containing a carbon-based solid electrolyte, and a all-solid-state battery. The carbon-based solid electrolyte has high ionic conductivity and deformation ability, and low elemental cost, can solve the key problem of solid-solid interface contact in all-solid electrolytes, and at the same time solve the problems of high cost and difficulty in commercial scale application of current solid electrolytes.

[0006] To achieve the above purpose, in the first aspect of the present invention, a carbon-based solid electrolyte is provided, with the general formula M a C b Xx Y y (1); wherein, M is selected from at least one of the metallic elements in Group IA, X is selected from at least one of halogens and monovalent negative groups, and Y is selected from at least one of the non-metallic elements in Group VIA and divalent negative groups; 1 ≤ a ≤ 6, 0.5 ≤ b ≤ 2, 0 < x ≤ 6, 0 ≤ y ≤ 6.

[0007] The carbon-based solid electrolyte provided by the present invention can be a ternary substance composed of M, C, and X; or it can be a quaternary substance composed of M, C, X, and Y.

[0008] In the present invention, without special instructions, the carbon-based solid electrolyte can be a single type of carbon-based solid electrolyte or a mixture of multiple types of carbon-based solid electrolytes, as long as it satisfies the above general formula (1).

[0009] Preferably, M is selected from at least one of Li, Na, and K.

[0010] Preferably, X is selected from at least one of F, Cl, Br, I, and CN, and preferably selected from at least one of Cl, Br, and I.

[0011] Preferably, Y is selected from at least one of O, S, Se, and Te, and preferably selected from O and / or S.

[0012] The second aspect of the present invention provides a preparation method of a carbon-based solid electrolyte, and the preparation method includes: in an inert atmosphere, mixing raw materials and performing ball milling or calcination to obtain a carbon-based solid electrolyte having the general formula M a C b X x Y y (1).

[0013] Wherein, M is selected from at least one of the metallic elements in Group IA, X is selected from at least one of halogens and monovalent negative groups, and Y is selected from at least one of the non-metallic elements in Group VIA and divalent negative groups; 1 ≤ a ≤ 6, 0.5 ≤ b ≤ 2, 0 < x ≤ 6, 0 ≤ y ≤ 6.

[0014] The third aspect of the present invention provides an electrode sheet, and the electrode sheet includes: the carbon-based solid electrolyte provided by the first aspect, or the carbon-based solid electrolyte prepared by the preparation method provided by the second aspect; wherein, the electrode sheet is a positive electrode sheet or a negative electrode sheet.

[0015] The fourth aspect of the present invention provides a film, and the film includes: the carbon-based solid electrolyte provided by the first aspect, or the carbon-based solid electrolyte prepared by the preparation method provided by the second aspect.

[0016] The fifth aspect of the present invention provides an all-solid-state battery, and the all-solid-state battery contains a positive electrode, a negative electrode, and an electrolyte;

[0017] Wherein, the positive electrode and the negative electrode are each independently selected from the electrode sheets provided in the third aspect, and / or, the electrolyte is selected from the membranes provided in the fourth aspect.

[0018] Through the above technical solution, the carbon-based solid electrolyte provided by the present invention with the general formula (1), by regulating the type of metal element M and C doping, not only greatly reduces the cost, but also has a low electrochemical reduction window and is stable to the electrode sheet; at the same time, the present invention adopts X and optional Y, which can effectively regulate the sublattice stacking form and effectively regulate the deformation ability of the carbon-based solid electrolyte, thereby promoting its full contact with the active particles and improving the ionic conductivity.

[0019] When the carbon-based solid electrolyte provided by the present invention is used in an all-solid-state battery, it can promote its full contact with the active material particles, improve the solid-solid interface contact problem in the all-solid-state battery, and further improve the electrochemical performance of the battery, especially the rate performance and cycle performance.

[0020] In addition, the raw materials used in the present invention have low costs, and dry ball milling is used for mixing, which simplifies the process flow and is conducive to industrial application. Description of the Drawings

[0021] Figure 1 is the XRD pattern of the carbon-based solid electrolyte S1 prepared in Example 1, the synthesis raw materials Li 2 O and CBr 4 ;

[0022] Figure 2a is the XPS pattern of the carbon-based solid electrolyte S1 prepared in Example 1;

[0023] Figure 2b is the XPS pattern of the synthesis raw material CBr 4 in Example 1. Detailed Embodiments

[0024] The endpoints and any values disclosed herein are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0025] The first aspect of the present invention provides a carbon-based solid electrolyte with the general formula M a C b X x Y y(1); wherein, M is selected from at least one of the metallic elements in Group IA, X is selected from at least one of halogens and monovalent groups, and Y is selected from the non-metallic elements in Group VIA and divalent groups; 1 ≤ a ≤ 6, 0.5 ≤ b ≤ 2, 0 < x ≤ 6, 0 ≤ y ≤ 6.

[0026] In the present invention, without special instructions, a, b, x, and y can be integers, decimals, or fractions, or any numbers within the above ranges.

[0027] In some embodiments of the present invention, preferably, when the carbon-based solid electrolyte contains Y, the general formula is M a’ C b’ X x’ Y y’ (2),

[0028] wherein, 1 ≤ a' ≤ 6, for example, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 6, and any value within the range composed of any two numerical values, preferably 1 ≤ a' ≤ 2;

[0029] wherein, 0.5 ≤ b' ≤ 2, for example, 0.5, 1, 1.5, 2, and any value within the range composed of any two numerical values;

[0030] wherein, 0 < x' ≤ 6, for example, 0.1, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 6, and any value within the range composed of any two numerical values, preferably 1 ≤ x' ≤ 6;

[0031] wherein, 0 < y' ≤ 6, for example, 0.1, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 6, and any value within the range composed of any two numerical values, preferably 0 < y' ≤ 3.

[0032] In the present invention, further preferably, in general formula (2), 1.5 ≤ a' ≤ 2, 1 ≤ b' ≤ 2, 2 ≤ x' ≤ 6, 0.5 ≤ y' ≤ 2.

[0033] In some embodiments of the present invention, preferably, when the carbon-based solid electrolyte does not contain Y, the general formula of the carbon-based solid electrolyte is M a” C b” X x” (3),

[0034] wherein, 1 ≤ a" ≤ 6, for example, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 6, and any value within the range composed of any two numerical values, preferably 1 ≤ a" ≤ 2;

[0035] where 0.5 ≤ b” ≤ 2, for example, 0.5, 1, 1.5, 2, and any value within the range formed by any two of these values;

[0036] where 0 < x” ≤ 6, for example, 0.1, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 6, and any value within the range formed by any two of these numerical values, preferably 3 ≤ x” ≤ 6.

[0037] In the present invention, M is selected from at least one of the non-hydrogen elements in Group IA. Preferably, in general formulas (1)-(3), M is selected from at least one of Li, Na, and K, more preferably selected from Li and / or Na, and most preferably Li.

[0038] In the present invention, by regulating the type of metal M, the ionic radius of the transported ions can be regulated. The ionic radii of Na and K in M are relatively large, and a greater energy barrier needs to be overcome for effective transport during the ion diffusion process. In contrast, the ionic radius of Li is relatively small and can be transported under a smaller energy barrier, resulting in better ionic conductivity.

[0039] In the present invention, preferably, in general formulas (1)-(3), X is selected from at least one of F, Cl, Br, I, and CN; more preferably, X is selected from at least one of Cl, Br, and I.

[0040] In the present invention, preferably, in general formulas (1)-(3), Y is selected from at least one of O, S, Se, and Te; more preferably, Y is selected from O and / or S.

[0041] In the present invention, preferably, in general formula (1), x / y > 0, for example, greater than 0.5, 0.8, 1, 1.2, 1.5, 1.8, 2, 2.1, 2.3, 2.5, 2.8, 3, 3.2, 3.5, 3.8, 4, 4.3, 4.5, 4.8, 4.9, 5, 5.5, 5.8, 6, 6.2, 6.4, 6.7, 6.9, 7, 7.5, 7.6, 7.8, 8, 8.5, 9…, and any value within the range formed by any two of these numerical values, preferably x / y > 1, and more preferably 2-5. In the present invention, by regulating the molar ratio of X and Y, the ion transport can be regulated and accelerated, thereby improving the ionic conductivity.

[0042] In the present invention, in general formula (1), 1 ≤ a ≤ 6, for example, 1, 1.5, 2, 2.5, 3, 4, 5, 6, and any value within the range formed by any two of these numerical values, preferably, 1 ≤ a ≤ 3.

[0043] In the present invention, in general formula (1), 0.5 ≤ b ≤ 2, for example, 0.5, 0.6, 0.8, 1, 1.5, 2, and any value within the range formed by any two of these numerical values, preferably, 1 ≤ b ≤ 2.

[0044] In the present invention, in general formula (1), 0 < x ≤ 6, for example, 1, 2, 3, 4, 4.5, 5, 6, and any value within the range formed by any two numerical values. Preferably, 2 ≤ x ≤ 6.

[0045] In the present invention, in general formula (1), 0 ≤ y ≤ 6, for example, 0, 0.5, 1, 1.5, 2, 2.5, 3, 4, 5, 6, and any value within the range formed by any two numerical values. Preferably, 0 ≤ y ≤ 3.

[0046] In the present invention, preferably, in general formula (2), x' / y' > 0, for example, greater than 0.5, 0.8, 1, 1.2, 1.5, 1.8, 2, 2.1, 2.3, 2.5, 2.8, 3, 3.2, 3.5, 3.8, 4, 4.3, 4.5, 4.8, 4.9, 5, 5.5, 5.8, 6, 6.2, 6.4, 6.7, 6.9, 7, 7.5, 7.6, 7.8, 8, 8.5, 9… and any value within the range formed by any two numerical values. Preferably, x' / y' > 1, more preferably 2 - 5, and even more preferably 1.

[0047] In some specific embodiments of the present invention, preferably, the carbon-based solid electrolyte is selected from Li 2 CBr 4 O 2 、Li 1.5 CBr 4.5 O 0.5 、Li 2 CCl 2 O 2 、Li 2 CBr 6 、Li 2 CBr 2 I 2 O、Li 2 CCl 2 Br 2 O、Li 2 CF 2 Br 2 O、Li 2 C(CN) 4 O、Li 2 CBr 4 S、Li 1.5 CBr 4.5 S 0.5 、Li 2 CCl 2 S 2 、Li 2 CBr 6 、Li 2 CBr2 I 2 S, Li 2 CCl 2 Br 2 S, Li 2 CF 2 Br 2 S, Na 2 CBr 4 O, Na 1.5 CBr 4.5 O 0.5 , Na 2 CCl 2 O 2 , Na 2 CBr 6 , Na 2 CBr 2 I 2 O, Na 2 CCl 2 Br 2 O, Na 2 CF 2 Br 2 O, Na 2 C(CN) 4 O, Na 2 CBr 4 S, Na 1.5 CBr 4.5 S 0.5 , Na 2 CCl 2 S 2 , Na 2 CBr 6 , Na 2 CBr 2 I 2 S, Na 2 CCl 2 Br 2 S, Na 2 CF 2 Br 2 S, K 2 CBr 4 O, K 1.5 CBr 4.5 O 0.5 , K 2 CCl 2 O 2 , K 2 CBr 6 , K 2 CBr 2 I 2 O, K 2 CCl 2 Br 2O, K 2 CF 2 Br 2 O, K 2 C(CN) 4 O, K 2 CBr 4 S, K 1.5 CBr 4.5 S 0.5 , K 2 CCl 2 S 2 , K 2 CBr 6 , K 2 CBr 2 I 2 S, Na 2 CCl 2 Br 2 S and K 2 CF 2 Br 2 At least one of S, preferably selected from Li 2 CBr 4 O, Li 1.5 CBr 4.5 O 0.5 , Li 2 CCl 2 O 2 , Li 2 CBr 6 , Li 2 CBr 2 I 2 O and Li 2 CBr 4 At least one of the S system.

[0048] In the present invention, there is a wide range of choices for the preparation method of the carbon-based solid electrolyte, as long as the above limitations are met. Preferably, the carbon-based solid electrolyte is prepared by ball milling or calcination of raw materials based on the element ratio of the general formula (1) in an inert atmosphere.

[0049] In the present invention, preferably, the carbon-based solid electrolyte has an amorphous structure.

[0050] The carbon-based solid electrolyte provided by the present invention has a high ionic conductivity, which can significantly improve the rate performance of the battery and slow down the attenuation of the capacity.

[0051] In the present invention, preferably, the ionic conductivity of the carbon-based solid electrolyte is ≥0.001 mS / cm. For example, 0.001 mS / cm, 0.003 mS / cm, 0.005 mS / cm, 0.008 mS / cm, 0.01 mS / cm, 0.02 mS / cm, 0.05 mS / cm, 0.08 mS / cm, 0.1 mS / cm, 0.2 mS / cm, 0.5 mS / cm, 0.8 mS / cm, 1 mS / cm, and any value within the range formed by any two of these values. Preferably, it is ≥0.01 mS / cm, and more preferably ≥0.1 mS / cm.

[0052] In the present invention, the ionic conductivity parameter is measured at room temperature, which refers to 25 ± 2 °C.

[0053] In the present invention, unless otherwise specified, the ionic conductivity parameter is measured by the alternating current impedance method, which includes: clamping the sample to be measured between two stainless steel disk electrodes (SS), measuring the ionic conductivity (σ) through electrochemical impedance spectroscopy (EIS), and calculating according to formula (1): wherein, R b is the volume resistance of the sample to be measured (R b determined from the impedance spectrum), and L and S are the thickness and area of the sample to be measured.

[0054] The carbon-based solid electrolyte provided by the present invention has excellent plasticity and toughness, can effectively improve the interfacial impedance between the electrode material and the solid electrolyte, and enhance the battery performance.

[0055] In a second aspect of the present invention, a preparation method of a carbon-based solid electrolyte is provided. The preparation method includes: mixing raw materials and performing ball milling or calcination to obtain a carbon-based solid electrolyte with the general formula M a C b X x Y y (1).

[0056] wherein, M is selected from at least one of the metal elements in Group IA, X is selected from at least one of halogens and monovalent negative groups, Y is selected from at least one of the non-metal elements in Group VIA and divalent negative groups; 1 ≤ a ≤ 6, 0.5 ≤ b ≤ 2, 0 < x ≤ 6, 0 ≤ y ≤ 6.

[0057] In the present invention, unless otherwise specified, the composition and type of the carbon-based solid electrolyte are in accordance with the above limitations, and the present invention will not elaborate herein.

[0058] In the present invention, unless otherwise specified, the ball milling or calcination can be carried out in an inert atmosphere, including but not limited to nitrogen atmosphere, helium atmosphere, argon atmosphere, neon atmosphere, etc., and preferably nitrogen atmosphere.

[0059] In the present invention, the mixing aims to uniformly mix the raw materials composed of the general formula (1). Preferably, in the general formula (1), when y≠0, the raw materials are selected from M m X n and C p Y q , or, M m’ Y n’ and C p’ X q’ , or, M m X n 、M m’ Y n’ 、C p Y q 、C p’ X q’ ; or, in the general formula (1), when y = 0, the raw materials are selected from M m X n and C p X q , M m’ X n’ and C, M and C p’ X q’ , where the subscripts m, n, p, q are positive integers.

[0060] In the present invention, the conditions for the mixing include: the temperature is 15 - 30°C, for example, 15°C, 20°C, 25°C, 30°C, and any value within the range composed of any two of these values, preferably 20 - 30°C; the time is 0.1 - 5 h, for example, 0.1 h, 0.5 h, 1 h, 1.5 h, 2 h, 3 h, 5 h, and any value within the range composed of any two of these values, preferably 0.1 - 2 h.

[0061] In the present invention, the ball milling aims to convert mechanical energy into chemical energy, causing the old bonds in the raw materials to break and become amorphous, forming a substance with the general formula (1). Preferably, the conditions for the ball milling include: the temperature is -20°C to 50°C, for example, -20°C, -10°C, 0°C, 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, 40°C, 50°C, and any value within the range composed of any two of these values, preferably 10 - 30°C; the time is 0.1 - 10 h, for example, 0.1 h, 0.5 h, 1 h, 1.5 h, 2 h, 3 h, 4 h, 5 h, 8 h, 10 h, and any value within the range composed of any two of these values, preferably 0.5 - 5 h.

[0062] In the present invention, further preferably, the conditions for ball milling further include: the ball-to-material ratio is 5 - 120:1, for example, 5:1, 10:1, 20:1, 40:1, 50:1, 60:1, 70:1, 80:1, 90:1, 100:1, and any value within the range composed of any two of these values, preferably 50 - 100:1; the rotation speed is 100 - 1000 rpm, for example, 100 rpm, 200 rpm, 500 rpm, 600 rpm, 700 rpm, 800 rpm, 1000 rpm, and any value within the range composed of any two of these values, preferably 500 - 800 rpm. In the present invention, the ball-to-material ratio refers to the mass ratio of the grinding balls to the raw materials.

[0063] In the present invention, the conditions for calcination include: the temperature is 80 - 150 °C, for example, 80 °C, 85 °C, 90 °C, 95 °C, 100 °C, 105 °C, 110 °C, 115 °C, 120 °C, 125 °C, 130 °C, 135 °C, 140 °C, 145 °C, 150 °C, preferably 90 - 120 °C.

[0064] In the present invention, further preferably, the calcination is carried out in an inert atmosphere.

[0065] In the present invention, preferably, the method further includes: successively subjecting the product of ball milling or calcination to pressing and / or heat treatment to obtain the carbon-based solid electrolyte.

[0066] The third aspect of the present invention provides an electrode sheet, which includes: the carbon-based solid electrolyte provided in the first aspect, or the carbon-based solid electrolyte prepared by the preparation method provided in the second aspect; wherein, the electrode sheet is a positive electrode sheet and / or a negative electrode sheet.

[0067] When the carbon-based solid electrolyte provided by the present invention is used in an electrode sheet, it can be placed inside or on the surface of the electrode sheet by means such as blending and coating, so as to effectively improve its full contact with the active material particles, and further improve the conductivity of the electrode sheet.

[0068] In some embodiments of the present invention, preferably, in the electrode sheet, the content of the carbon-based solid electrolyte is 0.1 - 25 wt%, for example, 0.1 wt%, 0.5 wt%, 1 wt%, 2 wt%, 5 wt%, 8 wt%, 10 wt%, 12 wt%, 15 wt%, 20 wt%, 25 wt%, and any value within the range composed of any two of these values, preferably 0.1 - 15 wt%.

[0069] In the present invention, without special instructions, the electrode sheet includes: a current collector and an active material layer loaded on the current collector, and the active material layer includes: an active material, a conductive agent, a binder, and the carbon-based solid electrolyte provided by the present invention.

[0070] In a specific embodiment of the present invention, the positive electrode sheet includes: a positive electrode current collector and a positive electrode active material layer, and the positive electrode active material layer includes: a positive electrode active material, a conductive agent, a binder, and a carbon-based solid electrolyte, wherein the mass ratio of the positive electrode active material, the conductive agent, the binder, and the carbon-based solid electrolyte is 70-99.9: 0-5: 0-5: 0.1-25, preferably 80-95: 0.1-3: 0.1-3: 0.1-15.

[0071] In the present invention, the positive electrode active material includes, but is not limited to, lithium cobalt oxide (such as LiCoO 2 ), lithium nickel oxide (such as LiNiO 2 ), lithium manganese oxide (such as LiMnO 2 , LiMn 2 O 4 ), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O 2 (NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O 2 (NCM523), LiNi 0.5 Co 0.25 Mn 0.25 O 2 (NCM211), LiNi 0.6 Co 0.2 Mn 0.2 O 2 (NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05 O 2 ) and its modified compounds, etc.; the positive electrode current collector includes, but is not limited to, aluminum foil, etc.

[0072] In the present invention, the conductive agent includes, but is not limited to, acetylene black, conductive carbon black, carbon fiber, carbon nanotube, and Ketjen black, etc.

[0073] In the present invention, the binder includes, but is not limited to, styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), carboxymethyl chitosan (CMCS), polyamide-imide (PAI), polyethyleneimine (PEI), polyimide (PI), and tert-butyl acrylate triethoxyvinylsilane (TBATEVS), etc.

[0074] In another specific embodiment of the present invention, the negative electrode sheet includes: a negative electrode current collector and a negative electrode active material layer. The negative electrode active material layer includes: a negative electrode active material, a conductive agent, a binder, and a carbon-based solid electrolyte. Among them, the mass ratio of the negative electrode active material, the conductive agent, the binder, and the carbon-based solid electrolyte is 70-99.9: 0-5: 0-5: 0.1-25, preferably 80-95: 0.1-3: 0.1-3: 0.1-15.

[0075] In the present invention, the negative electrode active material includes, but is not limited to, graphite, hard carbon, soft carbon, silicon, SiO, and Si / C, etc.; the negative electrode current collector includes, but is not limited to, copper foil, etc.

[0076] The fourth aspect of the present invention provides a film, and the film includes: the carbon-based solid electrolyte provided in the first aspect, or the carbon-based solid electrolyte prepared by the preparation method provided in the second aspect.

[0077] In the present invention, without special circumstances, the film or the electrode sheet can be prepared from a carbon-based solid electrolyte provided by the present invention, or can be prepared from a mixture of a plurality of carbon-based solid electrolytes provided by the present invention, or even can be prepared from a mixture of the carbon-based solid electrolyte provided by the present invention and a conventional solid electrolyte.

[0078] The fifth aspect of the present invention provides a all-solid-state battery, and the all-solid-state battery contains a positive electrode, a negative electrode, and an electrolyte;

[0079] Among them, the positive electrode and the negative electrode are each independently selected from the electrode sheets provided in the third aspect, and / or

[0080] The electrolyte is selected from the film provided in the fourth aspect.

[0081] In the present invention, without special circumstances, the electrolyte in the all-solid-state battery can all adopt the carbon-based solid electrolyte provided by the present invention, or can partially adopt the carbon-based solid electrolyte provided by the present invention.

[0082] The present invention will be described in detail below through examples.

[0083] The carbon-based solid electrolytes prepared in the examples and comparative examples were respectively pressed into tablets using a mold with a diameter of φ20 mm, packaged in an aluminum foil bag, and the ionic conductivity performance was tested under a sealed environment. The test results are all listed in Table 1.

[0084] Example 1

[0085] According to the molar ratio Li:C:Br:O = 2:1:4:1, weigh the raw materials Li 2 O and CBr 4 ;

[0086] In a glove box protected by a nitrogen atmosphere (the water and oxygen content is less than 0.01 ppm), mix the above raw materials at 25 °C using a mortar for 1 h, and transfer the obtained mixed material into a ball mill for ball milling (the ball-to-material ratio is 80:1, and zirconia grinding balls with a diameter of 5 mm are used). The conditions for ball milling include: the temperature is 25 °C, the rotation speed is 500 rpm, and the time is 2 h, to obtain the carbon-based solid electrolyte S1, with the general formula Li 2 CBr 4 O.

[0087] Among them, in the above carbon-based solid electrolyte S1, the valence states of Li, C, Br, and O are +1, +4, -1, and -2 respectively.

[0089] Among them, the XRD patterns of the above carbon-based solid electrolyte S1, the synthetic raw materials Li 2 O and CBr 4 are as shown in Figure 1 . Compared with the XRD patterns of Li 2 O and CBr 4 , the crystallinity of the carbon-based solid electrolyte S1 is greatly reduced, and the degree of amorphization is increased, proving that most of the synthetic materials have reacted to form an amorphous solid electrolyte.

[0090] Among them, as shown in Figure 2a , the peak position of C 2p in the XPS pattern of the above carbon-based solid electrolyte S1 is at 289.9 eV, Figure 2b which is the XPS pattern of the above synthetic raw material CBr 4 , that is, the standard peak position of C 2p of the raw material CBr 4 is at 288.8 eV, indicating that the coordination environment of the C element in the carbon-based solid electrolyte S1 has changed compared with the raw material CBr 4 , and new valence bonds have been generated.

[0091] Example 2

[0092] According to the molar ratio Li:C:Br:O = 2:1:2:2, weigh the raw materials Li 2 CO 3 , Li 2 O and CBr 4 ;

[0093] In a glove box under nitrogen atmosphere protection (where the water and oxygen content is less than 0.01 ppm), the above raw materials were mixed in a mortar at 25°C for 1 h. The obtained mixed material was transferred to a ball mill for ball milling (the ball-to-material ratio was 80:1, and zirconia grinding balls with a diameter of 5 mm were used). The conditions for ball milling included: a temperature of 25°C, a rotation speed of 500 rpm, and a time of 2 h, to obtain a carbon-based solid electrolyte S2, with the general formula Li 2 CBr 2 O 2 .

[0094] Among them, in the above carbon-based solid electrolyte S2, the valence states of Li, C, Br, and O are +1, +4, -1, and -2 respectively.

[0096] Example 3

[0097] According to the molar ratio Li:C:Br = 2:1:6, the raw materials LiBr and CBr were weighed 4 ;

[0098] In a glove box under nitrogen atmosphere protection (where the water and oxygen content is less than 0.01 ppm), the above raw materials were mixed in a mortar at 25°C for 1 h. The obtained mixed material was transferred to a ball mill for ball milling (the ball-to-material ratio was 80:1, and zirconia grinding balls with a diameter of 5 mm were used). The conditions for ball milling included: a temperature of 25°C, a rotation speed of 500 rpm, and a time of 2 h, to obtain a carbon-based solid electrolyte S3, with the general formula Li 2 CBr 6 .

[0099] Among them, in the above carbon-based solid electrolyte S3, the valence states of Li, C, and Br are +1, +4, and -1 respectively.

[0100] Example 4

[0101] According to the molar ratio Na:C:Br:O = 2:1:4:1, the raw materials Na 2 O and CBr 4 ;

[0102] In a glove box under nitrogen atmosphere protection (where the water and oxygen content is less than 0.01 ppm), the above raw materials were mixed in a mortar at 25°C for 1 h. The obtained mixed material was transferred to a ball mill for ball milling (the ball-to-material ratio was 80:1, and zirconia grinding balls with a diameter of 5 mm were used). The conditions for ball milling included: a temperature of 25°C, a rotation speed of 500 rpm, and a time of 2 h, to obtain a carbon-based solid electrolyte S4, with the general formula Na 2 CBr 4 O.

[0103] Among them, in the above carbon-based solid electrolyte S4, the valence states of Na, C, Br, and O are +1, +4, -1, and -2 respectively.

[0104] Example 5

[0105] Weigh the raw materials Li 2 S and CBr 4 ;

[0106] In a glove box protected by a nitrogen atmosphere (with a water and oxygen content of less than 0.01 ppm), mix the above raw materials at 25 °C using a mortar for 1 h. Transfer the obtained mixed material into a ball mill for ball milling (the ball-to-material ratio is 80:1, and zirconia grinding balls with a diameter of 5 mm are used). The conditions for ball milling include: temperature of 25 °C, rotation speed of 500 rpm, and time of 2 h to obtain the carbon-based solid electrolyte S5 with the general formula Li 2 CBr 4 S.

[0107] Among them, in the above carbon-based solid electrolyte S5, the valence states of Li, C, Br, and S are +1, +4, -1, and -2 respectively.

[0109] Example 6

[0110] Weigh the raw materials Li 2 O, CBr 4 and CI 4 ;

[0111] In a glove box protected by a nitrogen atmosphere (with a water and oxygen content of less than 0.01 ppm), mix the above raw materials at 25 °C using a mortar for 1 h. Transfer the obtained mixed material into a ball mill for ball milling (the ball-to-material ratio is 80:1, and zirconia grinding balls with a diameter of 5 mm are used). The conditions for ball milling include: temperature of 25 °C, rotation speed of 500 rpm, and time of 2 h to obtain the carbon-based solid electrolyte S6 with the general formula Li 2 CBr 2 I 2 O.

[0112] Among them, in the above carbon-based solid electrolyte S6, the valence states of Li, C, Br, I, and O are +1, +4, -1, -1, and -2 respectively.

[0114] Example 7

[0115] Weigh the raw materials Li 2 O and CCl 4 ;

[0116] In a glove box under a nitrogen atmosphere protection (with water and oxygen content less than 0.01 ppm), the above raw materials were mixed in a mortar at 25 °C for 1 h, and the obtained mixed material was transferred to a ball mill for ball milling (the ball-to-material ratio was 80:1, and zirconia grinding balls with a diameter of 5 mm were used). The conditions for ball milling included: temperature of 25 °C, rotation speed of 500 rpm, and time of 2 h, to obtain a carbon-based solid electrolyte S7 with the general formula Li 1.5 CCl 4.5 O 0.5 .

[0117] Among them, in the above carbon-based solid electrolyte S7, the valence states of Li, C, Cl, and O are +1, +4, -1, and -2 respectively.

[0118] Table 1

[0119] General formula Ionic conductivity at 25°C, mS / cm Example 1 <![CDATA[Li 2 CBr 4 O]]> <![CDATA[2.62×10 -1 > Example 2 <![CDATA[Li 2 CBr 2 O 2 > <![CDATA[1.21×10 -1 > Example 3 <![CDATA[Li 2 CBr 6 > <![CDATA[1.35×10 -2 > Example 4 <![CDATA[Sodium 2 Carbon Bromide 4 Oxygen]]> <![CDATA[3.54×10 -3 > Example 5 <![CDATA[Li 2 CBr 4 S]]> <![CDATA[8.90×10 -2 > Example 6 <![CDATA[Li 2 CBr 2 I 2 O]]> <![CDATA[7.33×10 -2 > Example 7 <![CDATA[Li 1.5 CCl 4.5 O 0.5 > <![CDATA[8.24×10 -2 >

[0120] It can be seen from the results in Table 1 that the carbon-based solid electrolytes provided by Examples 1-7 not only have the composition shown by M a C b X x Y y but also have high ionic conductivity. In particular, by regulating the types and stoichiometric ratios of M, X, and Y in the carbon-based solid electrolyte, the performance of the carbon-based solid electrolyte can be further regulated.

[0121] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A carbon-based solid electrolyte, characterized in that: The general formula is M a C b X x Y y (1); wherein M is selected from at least one of the metal elements of Group IA, X is selected from at least one of the halogens and the negative monovalent groups, and Y is selected from at least one of the non-metal elements of Group VIA and the negative divalent groups; 1≤a≤6, 0.5≤b≤2, 0 <x≤6,0≤y≤6。 2. The carbon-based solid electrolyte according to claim 1, wherein: When the carbon-based solid electrolyte contains Y, the general formula is M a’ C b’ X x’ Y y’ (2) Wherein, 1 ≤ a’ ≤ 6, 0.5 ≤ b’ ≤ 2, 0 < x’ ≤ 6, 0 < y’ ≤ 6; or When the carbon-based solid electrolyte does not contain Y, the general formula of the carbon-based solid electrolyte is M a” C b” X x” (3) Wherein, 1 ≤ a” ≤ 6, 0.5 ≤ b” ≤ 2, 0 < x” ≤ 6.

3. The carbon-based solid electrolyte according to claim 1 or 2, wherein: In general formulas (1)-(3), M is selected from at least one of Li, Na, and K; and / or, X is selected from at least one of F, Cl, Br, I, and CN, preferably selected from at least one of Cl, Br, and I; and / or, Y is selected from at least one of O, S, Se, and Te, preferably selected from O and / or S.

4. The carbon-based solid electrolyte according to any one of claims 1-3, wherein in general formula (1), x / y > 0, preferably x / y > 1, more preferably 2-5; and / or in general formula (2), x’ / y’ > 0, preferably x’ / y’ > 1, more preferably 2-5.

5. The carbon-based solid electrolyte according to any one of claims 1 to 4, wherein: The carbon-based solid electrolyte has an amorphous structure; and / or, the ionic conductivity of the carbon-based solid electrolyte is ≥ 0.001 mS / cm, preferably ≥ 0.01 mS / cm, more preferably ≥ 0.1 mS / cm.

6. A method for preparing a carbon-based solid electrolyte, characterized in that: The preparation method comprises: mixing raw materials and ball milling or calcining to obtain a product having a general formula of M a C b X x Y y (1) A carbon-based solid electrolyte composed of: Wherein, M is selected from at least one of the metallic elements in Group IA, X is selected from at least one of halogens and monovalent negative groups, Y is selected from at least one of the non-metallic elements in Group VIA and divalent negative groups; 1 ≤ a ≤ 6, 0.5 ≤ b ≤ 2, 0 < x ≤ 6, 0 ≤ y ≤ 6.

7. The preparation method according to claim 6, wherein: The conditions for ball milling include: the temperature is -20°C to 50°C, preferably 10-30°C; the time is 0.1-10 h, preferably 0.5-5 h; and / or, the conditions for ball milling further include: the ball-to-material ratio is 5-120:1, preferably 50-100:1; the rotation speed is 100-1000 rpm, preferably 500-800 rpm; and / or, the conditions for ball milling further include performing in an inert atmosphere.

8. The preparation method according to claim 6, wherein: The conditions for calcination include: the temperature is 80-150°C, preferably 90-120°C; and / or, the calcination further includes performing in an inert atmosphere.

9. A pole piece, characterized in that: The electrode sheet includes: the carbon-based solid electrolyte according to any one of claims 1-5, or the carbon-based solid electrolyte prepared by the preparation method according to any one of claims 6-8; wherein, the electrode sheet is a positive electrode sheet and / or a negative electrode sheet; Preferably, in the electrode sheet, the content of the carbon-based solid electrolyte is 0.1-25 wt%, preferably 0.1-15 wt%.

10. A film, characterized in that The film includes: the carbon-based solid electrolyte according to any one of claims 1-5, or the carbon-based solid electrolyte prepared by the preparation method according to any one of claims 6-8; Preferably, the application of the film in a lithium-ion battery, preferably in an electrolyte layer and a separator.

11. An all-solid-state battery, characterized in that: The all-solid-state battery contains a positive electrode, a negative electrode, and an electrolyte; wherein, the positive electrode and the negative electrode are each independently selected from the electrode sheet according to claim 9; and / or, the electrolyte is selected from the film according to claim 10.

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