Preparation method for and use of lithium-silicon alloy material

Abstract

A preparation method for and a use of a lithium-silicon alloy material. Under room temperature conditions, a layer of asphalt is pre-coated on the surface of a lithium-silicon alloy, and then a layer of LiF is coated, a lithium-silicon alloy negative electrode sheet is prepared via dry processing, and then assembly is performed to obtain a sulfide all-solid-state lithium battery. This lithium-silicon alloy negative electrode has high capacity (greater than 1500 mAh g-1). Coating materials having adhesive properties are selected to sequentially perform carbon coating and fluorine coating on the lithium-silicon alloy, so that the lithium-silicon negative electrode sheet can be easily prepared at room temperature. This two-layer coating method, while ensuring that the capacity of the lithium-silicon alloy is not reduced, improves the electronic conductivity of the lithium-silicon alloy negative electrode, effectively suppresses the formation of lithium dendrites on the negative electrode, and facilitates the formation of a compatible negative electrode interface with a sulfide solid-state electrolyte, thereby enabling the commercial application of sulfide all-solid-state lithium batteries.

Description

Preparation method of lithium silicon alloy material and application thereof Technical Field

[0001] The present invention relates to the field of solid-state battery technology, and specifically to a preparation method of a lithium-silicon alloy material and its application, especially a dry method for preparing a double-layer coated lithium-silicon alloy negative electrode at room temperature and a sulfide all-solid-state lithium battery. Background Art

[0002] In order to solve the range anxiety and safety issues of existing electric vehicles, all-solid-state lithium-ion batteries with high energy density and safety are an excellent direction for commercial applications. Sulfide solid electrolytes have ionic conductivity comparable to that of liquid electrolytes and are expected to achieve commercial applications of all-solid-state batteries, giving electric vehicles ultra-long driving range and ultra-safety. Silicon is a high-capacity negative electrode material, but it has a low first efficiency and a large volume expansion effect, which greatly limits the application scope of sulfide all-solid-state lithium batteries. Lithium-silicon alloys have high capacity (>1500mAh g -1 ), which is five times higher than that of graphite negative electrode, and to a certain extent avoids the volume expansion effect during charging and discharging. At the same time, the lithium ions contained in lithium-silicon alloy greatly improve the initial efficiency and cycle stability of the battery, and it is a negative electrode material with good application prospects.

[0003] However, highly active lithium-silicon alloys have significant safety risks and low electronic conductivity, so the surface of the lithium-silicon alloy needs to be coated. The present invention aims to pre-coat the surface of the lithium-silicon alloy with a layer of asphalt, and then coat it with a layer of LiF, to assemble it into a sulfide all-solid-state battery. This double-layer coating method not only improves the electronic conductivity of the lithium-silicon alloy negative electrode while ensuring that the capacity of the lithium-silicon alloy is not reduced, but also effectively suppresses the formation of lithium dendrites at the negative electrode, making it easy to form a friendly negative electrode interface with the sulfide solid electrolyte, thereby realizing the commercial application of sulfide all-solid-state batteries.

[0004] CN113130868A discloses a method for preparing a composite material containing silicon oxide. The composite material comprises silicon oxide, lithium silicon composite material, fluoride and carbon from the inside out. The specific method is: (1) disproportionate silicon oxide; (2) in a non-oxidizing atmosphere, the disproportionate silicon oxide, metallic lithium and carbon source are mixed and ball milled; (3) fluorination treatment; (4) carbon coating. The composite material provided by this method still has silicon oxide as its core. The silicon oxide is pre-lithiated to improve the initial efficiency, and then the stability of the composite material is improved by fluorination treatment and carbon coating in sequence. This patent is suitable for liquid batteries. The disproportionation reaction temperature in the patent is greater than 700°C. After ball milling with lithium source and carbon source, the result is a lithium silicon alloy / lithium silicate composite layer. The fluorination treatment is a liquid phase reaction, and the carbon coating is a gas phase / liquid phase coating. Compared with the present invention, the raw materials, coating material properties and methods, the structure of the negative electrode material, the preparation conditions, and the application range are all different, which are essentially different.

[0005] CN108565414 discloses a lithium-silicon alloy material with a surface modification layer and its preparation method. The surface modification layer is a film-forming hydrophobic polymer material, including polyvinylidene fluoride (PVDF) in this patent. The method is to dissolve lithium-silicon particles and a hydrophobic polymer material (such as PVDF) in an organic solvent, and then obtain a lithium-silicon alloy with a surface modification layer by solid-liquid separation or evaporation. The alloy is carbon-modified. Compared with the present invention, this method is applied to liquid batteries and is a wet coating method. The ultimate goal of PVDF coating is to achieve carbon coating, not fluorine coating, which is essentially different from the present invention.

[0006] Unlike the aforementioned patents, the present invention utilizes high-energy ball milling at room temperature to sequentially coat the lithium-silicon alloy with carbon and then fluorine. The coating materials exhibit excellent adhesion, thereby enhancing electronic conductivity and interfacial stability while also facilitating the formation of a supportive dry-process negative electrode sheet. This eliminates the need for additional conductive agents and binders, effectively increasing the energy density of the assembled battery. This room-temperature reaction effectively ensures safe production while reducing costs, providing a promising approach for commercial production.

[0007] Summary of the Invention

[0008] In response to the shortcomings of the existing technology, the present invention provides a method for preparing a lithium-silicon alloy material and its application, specifically a room-temperature dry-process preparation technology for a double-layer coated lithium-silicon alloy negative electrode with high electronic conductivity and good interface stability. In terms of technical route, the negative electrode coating raw material is mainly composed of a common binder, which not only takes advantage of the advantages of dry film formation, but also increases the content of active materials in the lithium-silicon alloy negative electrode, which can improve the energy density of assembled sulfide solid-state lithium batteries; in terms of material function, it not only improves electronic conductivity but also optimizes the interface stability between the lithium-silicon negative electrode and the sulfide solid electrolyte; in terms of industrial application, this room-temperature reaction and dry-process preparation technology not only improves production safety but also reduces enterprise costs, and has important research and development prospects.

[0009] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0010] The present invention relates to a method for preparing a lithium-silicon alloy material, comprising the following steps:

[0011] S1. In a protective atmosphere, coating the surface of lithium-silicon alloy particles with a layer of asphalt to obtain asphalt-coated lithium-silicon alloy;

[0012] S2. Mixing the asphalt-coated lithium-silicon alloy with a fluorine-containing binder to obtain a double-layer coated lithium-silicon alloy negative electrode material with an asphalt-binder coating layer.

[0013] As an embodiment of the present invention, in step S1, the protective gas is argon, the water content of the protective gas is less than 1 ppm, and the oxygen content is less than 1 ppm. The negative electrode material of the present invention is prepared at room temperature.

[0014] As an embodiment of the present invention, in step S1, the particle size of the lithium silicon alloy particles is 500nm to 10μm; the lithium silicon alloy includes LiSi, Li 12 Si7、Li 13 Si4、Li 15 Si4、Li 21 Si4、Li 22 One or more of Si5.

[0015] In one embodiment of the present invention, in step S1, coating the lithium-silicon alloy particles with asphalt is achieved by mixing the particles with asphalt and mechanically milling them at a speed of 200 to 550 rpm for 1 to 4 hours. The asphalt acts like an adhesive, coating the surface of the lithium-silicon alloy particles without causing them to fall off.

[0016] In one embodiment of the present invention, in step S1, the asphalt is ordinary petroleum asphalt powder, not asphalt that is liquid at room temperature, and has a particle size of 5 to 20 μm. The carbon in the asphalt achieves carbon coating of the lithium-silicon alloy, i.e., the lithium-silicon alloy particles are first carbon-coated and then fluorine-coated.

[0017] As an embodiment of the present invention, in steps S1 and S2, the weight ratio of lithium silicon alloy, asphalt and fluorine-containing binder is (85-95): (4-8): (0.5-2).

[0018] As an embodiment of the present invention, in step S2, the fluorine-containing binder includes one or more of polylithium fluoride, polytetrafluoroethylene, tetrafluoroethylene, and carbon fluoride.

[0019] As an embodiment of the present invention, in step S2, the mixing method is one or more of shaking, grinding, mechanical stirring, and mechanical ball milling.

[0020] The present invention also provides a use of the double-layer coated lithium-silicon alloy negative electrode material in the preparation of a sulfide all-solid-state lithium battery. The double-layer coated lithium-silicon alloy negative electrode material of the present invention is used in an all-solid-state lithium battery; the sulfide all-solid-state lithium battery includes a sulfide solid electrolyte, a positive electrode plate, and a negative electrode plate, wherein the negative electrode active material of the negative electrode plate is the lithium-silicon alloy material obtained by the preparation method.

[0021] As an embodiment of the present invention, the sulfide solid electrolyte includes Li6PS5Cl, Li 5.5 PS 4.5 Cl 1.5 、Li6PS5Br、Li6PS5I、Li 11 Si2PS 12 、Li 10 SnP2S 12 、Li 10 GeP2S 12 、Li 3.25 Ge 0.25 P 0.75 S4, Li 10 Ge(P 1-x Sb x )2S 12 、Li 6.6 Ge 0.6 P 0.4 One or more of S5I. 10 Ge(P 1-x Sb x )2S 12 0 <x<1。

[0022] As an embodiment of the present invention, the positive electrode active material of the positive electrode plate includes one of NCM811, NCM622, NCM523, S, LiFePO4, and LiCoO2.

[0023] The present invention also provides a method for preparing a sulfide all-solid-state lithium battery, comprising the following steps:

[0024] A1. Roll-pressing the double-layer coated lithium-silicon alloy negative electrode material to obtain negative electrode sheets of different thicknesses;

[0025] A2. Assemble a pressure battery together with the negative electrode plate, the sulfide solid electrolyte, and the positive electrode plate to obtain the sulfide all-solid-state lithium battery.

[0026] As an embodiment of the present invention, in step A1, the rolling is performed repeatedly using a stainless steel cylinder.

[0027] As an embodiment of the present invention, in step A1, the thickness of the negative electrode sheet is controlled to be 15 to 45 μm.

[0028] The present invention utilizes a double-layer coating of fluorine and carbon, where a binder such as PVDF provides a fluorine coating rather than the carbon coating of PVDF and an organic solvent used in conventional liquid batteries. This fluorine coating stabilizes the interface between the negative electrode and the electrolyte, inhibiting side reactions during charge and discharge.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] (1) It not only improves the electronic conductivity, but also optimizes the interfacial stability between the lithium-silicon alloy anode and the sulfide solid electrolyte;

[0031] (2) It not only takes advantage of the dry film formation process, but also increases the content of active materials in the lithium-silicon alloy negative electrode, thereby improving the energy density of the assembled sulfide solid-state lithium battery;

[0032] (3) It not only improves production safety but also reduces enterprise costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0034] FIG1 is a SEM image of a double-layer coated lithium-silicon alloy negative electrode prepared in Example 1;

[0035] FIG2 is the first charge and discharge curves of the sulfide all-solid-state batteries prepared in Example 1 and Comparative Example 1;

[0036] FIG3 is the first charge and discharge curves of the sulfide all-solid-state batteries prepared in Example 2 and Comparative Example 4;

[0037] FIG4 is a 100-cycle curve of the sulfide all-solid-state batteries prepared in Example 3 and Comparative Example 3;

[0038] FIG5 is a complete negative electrode sheet prepared in Example 5;

[0039] FIG6 is the first cycle charge and discharge curves of Examples 6 to 9 at a rate of 0.1C. DETAILED DESCRIPTION

[0040] The present invention will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those skilled in the art, several changes and improvements can be made without departing from the scope of the present invention. These all fall within the scope of protection of the present invention.

[0041] Example 1

[0042] The present invention provides a method for preparing a lithium-silicon alloy material, and the method and the preparation of a battery include the following steps:

[0043] (1) In a glove box filled with argon (water content less than 1 ppm, oxygen content less than 1 ppm), Li 15 Si4 alloy (particle size 1 μm) and asphalt (high-temperature petroleum asphalt powder, particle size 10 μm) were placed in a zirconia ball mill with a ball-to-material ratio of 10:1, a ball milling time of 1 h, and a ball milling speed of 400 rpm.

[0044] (2) After ball milling, the asphalt-coated Li 15 The Si4 alloy was scraped from the ball mill and weighed, and then evenly ground with PTFE in a mortar for 15 minutes. 15 The mass ratio of Si4 alloy to PTFE is 99:1. After grinding, a double-layer coated alloy with a plasticine texture is obtained, and the SEM image is shown in Figure 1.

[0045] (3) Use a stainless steel metal rod to roll it to a thickness of 15 μm and set aside.

[0046] (4) Weigh Li 5.5 PS 4.5 Cl 1.5 80 mg of powder was evenly spread in another cylindrical tablet mold with a diameter of 10 mm, and a pressure of 135 MPa was applied to pre-press the electrolyte.

[0047] (5) NCM811 powder, electrolyte Li 5.5 PS 4.5 Cl 1.52. The conductive carbon fibers are manually ground in a mortar at a mass ratio of 77:20:3 until they are evenly mixed to obtain positive electrode powder. 10 mg of positive electrode powder is weighed and evenly spread on the surface of the electrolyte electrode and a pressure of 350 MPa is applied to press the two into sheets. The sheets are demolded to obtain the electrolyte / positive electrode sheet.

[0048] (6) The double-layer coated lithium silicon alloy negative electrode sheet and the electrolyte / positive electrode sheet are assembled in a pressure battery mold respectively. The top of the negative electrode must be in contact with the electrolyte. The Al foil current collector is assembled on the positive electrode sheet, and the Cu foil current collector is assembled on the negative electrode. After the assembly is completed, a pressure of 75 MPa is applied to obtain a sulfide all-solid-state lithium battery.

[0049] Example 2

[0050] The present invention provides a method for preparing a lithium silicon alloy material, which is basically the same as the preparation steps of Example 1, except that: in step (1), the ball milling speed is changed to 200 rpm and the ball milling time is changed to 4 hours.

[0051] Example 3

[0052] The present invention provides a method for preparing a lithium-silicon alloy material, which is basically the same as the preparation steps of Example 1, except that PTFE is replaced by PVDF in step (2).

[0053] Example 4

[0054] The present invention provides a method for preparing a lithium silicon alloy material, which is basically the same as the preparation steps of Example 1, except that the grinding step in step (2) is changed to ball milling, the ball milling speed is 200 rpm, and the time is 4 hours.

[0055] Example 5

[0056] The present invention provides a method for preparing a lithium silicon alloy material, which is substantially the same as the preparation steps of Example 1, except that: the Li 15 Si4 alloy replaced by Li 21 Si4.

[0057] Example 6

[0058] The present invention provides a method for preparing a lithium silicon alloy material, which is substantially the same as the preparation steps of Example 1, except that: the Li 15 The mass ratio of Si4 alloy to asphalt was adjusted to 91:8.

[0059] Example 7

[0060] The present invention provides a method for preparing a lithium silicon alloy material, which is basically the same as the preparation steps of Example 1, except that: in step (2), the asphalt-coated Li 15The mass ratio of Si4 alloy to PTFE is 99.5:0.5.

[0061] Example 8

[0062] The present invention provides a method for preparing a lithium-silicon alloy material, which is substantially the same as the preparation steps of Example 1, except that the thickness in step (3) is adjusted to 40 μm.

[0063] Example 9

[0064] The present invention provides a method for preparing a lithium silicon alloy material, which is substantially the same as the preparation steps of Example 1, except that: the Li 5.5 PS 4.5 Cl 1.5 Replaced with LGPS, accordingly, Li in (5) 5.5 PS 4.5 Cl 1.5 Also replaced with LGPS.

[0065] Example 10

[0066] The difference from Example 1 is that the NCM811 in step (5) is replaced with an S positive electrode.

[0067] Comparative Example 1

[0068] The present invention provides a method for preparing a lithium silicon alloy material, which is basically the same as the preparation steps of Example 1, except that: uncoated Li 15 Si4 alloy was dissolved in toluene-styrene-butadiene rubber and coated on Cu current collector to obtain negative electrode. 15 The Si4 alloy was dissolved in 70 mg of toluene-styrene-butadiene rubber solution (toluene-styrene-butadiene rubber mass ratio was 100:4), magnetically stirred for 4 h, and then the above solution was coated on the surface of the Cu current collector with a final coating thickness of 15 μm.

[0069] Comparative Example 2

[0070] The present invention provides a method for preparing a lithium-silicon alloy material, which is basically the same as the preparation steps of Example 1, except that the asphalt in step (1) is replaced by conductive carbon black.

[0071] Comparative Example 3

[0072] The present invention provides a method for preparing a lithium-silicon alloy material, which is substantially the same as the preparation steps of Example 3, except that step (2) is not performed.

[0073] Comparative Example 4

[0074] The present invention provides a method for preparing a lithium silicon alloy material, which is substantially the same as the preparation steps of Example 1, except that step (1) is not performed, and Li 15 Si4 alloy is directly mixed with PTFE.

[0075] Comparative Example 5

[0076] The present invention provides a method for preparing a lithium silicon alloy material, which is substantially the same as the preparation steps of Example 1. The difference from Example 1 is that the order of steps (1) and (2) is reversed. Li 15 Si4 alloy is mixed with PTFE and then mixed with asphalt.

[0077] The fluorine coating is to stabilize the interface between the negative electrode and the electrolyte layer and inhibit the occurrence of side reactions. The carbon coating will directly contact the electrolyte. The sulfide electrolyte is very active and can be easily reduced by carbon. Therefore, the carbon-coated negative electrode needs to be coated with fluorine for the second time to stabilize the negative electrode interface.

[0078] Comparative Example 6

[0079] The present invention provides a method for preparing a lithium silicon alloy material, which is basically the same as the preparation steps of Example 1, except that asphalt and PTFE are first mixed and then mixed with Li 15 The Si4 alloy was mixed and ball milled according to step (1).

[0080] Performance Testing

[0081] First efficiency: The all-solid-state battery was tested using the Xinwei battery testing system (model: CT-4000). A 1C rate charge and discharge process was used to test the first charge and discharge capacity of the solid-state lithium battery. First efficiency (%) = first discharge capacity / first charge capacity × 100%.

[0082] Cycling performance test: The all-solid-state battery was tested using a 2C rate charge and discharge cycle for 100 times to test the battery's capacity retention rate. Capacity retention rate = 100th discharge capacity / first cycle discharge capacity × 100%.

[0083] Figure 2 shows the first-cycle charge and discharge curves of Example 1 and Comparative Example 1 at a rate of 0.5C. The first-cycle discharge capacity of Example 1 is 167.64 mAh / g, the first-cycle charge capacity is 238.40 mAh / g, and the first efficiency is 70.32%; the first-cycle discharge capacity of Comparative Example 1 is 143.95 mAh / g, the first-cycle charge capacity is 241.36 mAh / g, and the first efficiency is 59.64%.

[0084] Figure 3 shows the first-cycle charge and discharge curves of Example 2 and Comparative Example 4 at a rate of 0.2C. It can be seen that the first-cycle discharge capacity of Example 2 is 196.69 mAh / g, the first-cycle charge capacity is 231.22 mAh / g, and the first efficiency is 85.07%; the first-cycle discharge capacity of Comparative Example 4 is 173.06 mAh / g, the first-cycle charge capacity is 253.25 mAh / g, and the first efficiency is 68.34%.

[0085] Figure 4 shows the charge and discharge curves of Example 3 and Comparative Example 3 at a 2C rate for 100 cycles. The first-cycle discharge capacity of Example 3 is 124.77 mAh / g, the 100th-cycle discharge capacity is 121.73 mAh / g, and the capacity retention rate is 97.56%. The first-cycle discharge capacity of Comparative Example 3 is 117.12 mAh / g, the 100th-cycle discharge capacity is 99.55 mAh / g, and the capacity retention rate is 84.99%.

[0086] FIG5 is a complete negative electrode sheet prepared in Example 5.

[0087] Figure 6 shows the first-cycle charge and discharge curves of Examples 6 to 9 at a rate of 0.1C. The first-cycle discharge capacity of Example 6 is 170.64mAh / g, the first-cycle charge capacity is 217.79mAh / g, and the first efficiency is 78.35%; the first-cycle discharge capacity of Example 7 is 187.34mAh / g, the first-cycle charge capacity is 230.43mAh / g, and the first efficiency is 81.3%; the first-cycle discharge capacity of Example 8 is 170.82mAh / g, the first-cycle charge capacity is 215.61mAh / g, and the first efficiency is 79.23%; the first-cycle discharge capacity of Example 9 is 179.55mAh / g, the first-cycle charge capacity is 221.49mAh / g, and the first efficiency is 81.06%.

[0088] Example 10: After replacing NCM811 with an S positive electrode, the initial efficiency of the full battery is 75%, and the capacity retention rate after 1000 cycles at a 1C rate is 76%, indicating that the lithium-silicon alloy material of the present invention can be used as a negative electrode in combination with an S positive electrode.

[0089] Comparative Example 2 replaces the asphalt coating with conductive carbon black, that is, carbon is only added to the negative electrode as a conductive agent. Due to the physical smoothness of the conductive carbon black, the alloy cannot be coated. At this time, the single binder PTFE cannot prompt the hard alloy powder to form a self-supporting sheet. The negative electrode sheet is very prone to brittle fracture, making it difficult to achieve commercial application.

[0090] Comparative Example 4 is not 15 The Si4 alloy is pre-coated with carbon, so the electronic conductivity of the alloy negative electrode drops sharply, and the electron conduction is blocked in the solid-state battery, affecting the high-rate cycle stability of the entire battery.

[0091] Comparative Example 5: First, 15 The Si4 alloy is fluorine-coated and then carbon-coated, and the outer carbon layer is in direct contact with the electrolyte, which can easily lead to the reduction of the electrolyte and the decrease of the negative electrode interface stability.

[0092] In Comparative Example 6, the viscous PTFE and asphalt were pre-mixed and could not be uniformly mixed under ball milling conditions. 15 Ball milling of Si4 alloy can neither achieve uniform fluorine coating nor uniform carbon coating, but can only exert its adhesion and conductivity, resulting in uneven conductivity of the negative electrode, inducing uneven deposition of lithium, which is not conducive to interface stability.

[0093] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art may make various variations or modifications within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A method for preparing a lithium-silicon alloy material for a sulfide all-solid-state lithium battery, characterized in that: The preparation method comprises the following steps: S1. In a protective atmosphere, a layer of asphalt is coated on the surface of lithium silicon alloy particles to obtain asphalt-coated lithium silicon alloy; S2, mixing the asphalt-coated lithium-silicon alloy with a fluorine-containing binder to obtain a double-layer coated lithium-silicon alloy negative electrode material with an asphalt-binder coating layer; In step S1, coating with a layer of asphalt is performed by mixing lithium silicon alloy particles with asphalt and then ball milling; the rotation speed of the ball mill is 200-550 rpm, and the ball milling time is 1-4 hours; the asphalt is petroleum asphalt powder, and the particle size is 5-20 μm; In steps S1 and S2, the weight ratio of lithium silicon alloy, asphalt and fluorine-containing binder is 85-95:4-8:0.5-2.

2. The preparation method according to claim 1, characterized in that: In step S1, the particle size of the lithium silicon alloy particles is 500nm-10μm; the lithium silicon alloy includes LiSi, Li 12 Si7、Li 13 Si4、Li 15 Si4、Li 21 Si4、Li 22 One or more of Si5.

3. The preparation method according to claim 1, characterized in that: In step S2, the fluorine-containing binder includes one of polylithium fluoride, polytetrafluoroethylene, tetrafluoroethylene, and carbon fluoride.

4. The preparation method according to claim 1, characterized in that: In step S2, the mixing method is one or more of shaking, grinding, mechanical stirring, and mechanical ball milling.

5. A sulfide all-solid-state lithium battery, characterized in that: It comprises a sulfide solid electrolyte, a positive electrode sheet, and a negative electrode sheet; the negative electrode active material of the negative electrode sheet is a double-layer coated lithium silicon alloy negative electrode material obtained by the preparation method according to claim 1; the sulfide solid electrolyte comprises Li6PS5Cl, Li 5.5 PS 4.5 Cl 1.5 、Li6PS5Br、Li6PS5I、Li 11 Si2PS 12 , Li 10 SnP2S 12 , Li 10 GeP2S 12 , Li 3.25 Ge 0.25 P 0.75 S4, Li 10 Ge(P 1-x Sb x )2S 12 , Li 6.6 Ge 0.6 P 0.4 One or more of S5I.

6. A method for preparing a sulfide all-solid-state lithium battery as claimed in claim 5, characterized in that: The steps include: A1. Roll-pressing the double-layer coated lithium silicon alloy negative electrode material to obtain a negative electrode sheet; A2. Assemble the negative electrode plate, the sulfide solid electrolyte and the positive electrode plate into a battery to obtain the sulfide all-solid-state lithium battery.

Images