A sulfide solid-state electrolyte for suppressing dendrite growth, a preparation method and applications thereof

Abstract

The application relates to a sulfide solid electrolyte for inhibiting dendrite growth, a preparation method and application, and belongs to the technical field of lithium ion solid-state batteries. The chemical general formula of the sulfide solid electrolyte is aMCl b -Li 7‑c PS 6‑c X c wherein M is one or more of Mg, Ca, Sr, Ba, Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er and Tm, MCl b accounts for 1-40 wt.% of the whole electrolyte, X is one or more of Cl, Br and I, and 1<=c<=2. The sulfide solid electrolyte has high room-temperature ionic conductivity and good dendrite inhibition capacity, can greatly reduce the short-circuit risk of prepared lithium ion batteries in the process of high current density and long-time circulation, and has simple synthesis method, can be used for preparing full-solid-state lithium ion batteries, and has good practicability.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion solid-state battery technology, specifically relating to a sulfide solid electrolyte that inhibits dendrite growth, its preparation method and application, particularly for the preparation of all-solid-state lithium-ion batteries. Background Technology

[0002] As the demand for power batteries gradually increases, the advantages of all-solid-state batteries are becoming increasingly apparent: high safety, high energy density, long lifespan, and low cost, leading to broad application prospects and attracting numerous companies and research institutions to invest in research and development. However, all-solid-state battery technology still faces challenges such as the need to improve the ionic conductivity of solid electrolytes, poor contact between electrodes and electrolytes, and lithium dendrite growth.

[0003] In all-solid-state lithium metal batteries based on solid-state electrolytes, two main factors have been identified as the primary drivers of poor lithium dendrite nucleation and propagation. The first factor is the presence of dendrites induced by the negative electrode. These dendrites initially form at the lithium / solid-state electrolyte interface and subsequently penetrate into the solid-state electrolyte through pre-existing cracks, defects, or contact failures, leading to battery performance degradation or even complete short circuits. The second factor is the presence of dendrites induced by grain boundaries. These dendrites nucleate independently at grain boundaries within the solid-state electrolyte and eventually grow together, causing short circuits.

[0004] Current methods for improving dendrite formation in solid-state batteries include applying mechanical stress, electrolyte modification, interface engineering, adding protective layers, optimizing electrolyte microstructure, and using high-shear modulus electrolytes. Each method has its unique advantages and limitations. Future research needs to comprehensively consider factors such as materials, processes, and costs to develop more efficient and safer solid-state battery technologies. Summary of the Invention

[0005] To address the aforementioned problems, the present invention aims to provide a sulfide solid electrolyte that inhibits dendrite growth, its preparation method, and its applications, particularly for the fabrication of all-solid-state lithium-ion batteries. This sulfide solid electrolyte is prepared through a two-step, short-duration, low-speed ball milling process, which effectively inhibits the growth of metal dendrites and improves the limiting current density of lithium-ion solid-state batteries.

[0006] In a first aspect, the present invention provides a sulfide solid electrolyte that inhibits dendrite growth, having the general chemical formula aMCl. b -Li 7-c PS 6-c X cWhere M is one or more of Mg, Ca, Sr, Ba, Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, and Tm, and b depends on the chemical valence state of element M; the range of a is 0.01 ≤ a ≤ 0.4, representing MCl. b It accounts for 1-40% of the total mass of the sulfide solid electrolyte; X is one or more of Cl, Br, and I; 1≤c≤2, and Li is limited to 7-c PS 6-c X c The molar ratio of each element in the mixture.

[0007] Furthermore, the range of a is 0.05 ≤ a ≤ 0.2;

[0008] Furthermore, M can be Ca, Sm, Y, La, or Ba;

[0009] Furthermore, the range of c is 1 ≤ c ≤ 1.5;

[0010] Furthermore, the room temperature ionic conductivity of the sulfide solid electrolyte is 10. -3 ~10 -2 S cm -1 Limiting current density ≥ 2.5 mA cm⁻¹ -2 .

[0011] Secondly, the present invention provides a method for preparing the above-mentioned sulfide solid electrolyte, the steps of which are as follows:

[0012] 1) Electrolyte Li 7-c PS 6-c X c Preparation: Based on the value of c, raw materials Li₂S, LiX, and P₂S₅ were weighed in molar proportions, ground and mixed, and then ball-milled. The ball-milled product was then sintered under vacuum and naturally cooled to room temperature to obtain the electrolyte Li. 7-c PS 6-c X c ;

[0013] 2) aMCl b -Li 7-c PS 6-c X c Preparation: Based on the value of a, weigh MCl according to the mass ratio. b and Li 7-c PS 6-c X c After grinding and mixing, the mixture is ball-milled to obtain the sulfide solid electrolyte aMCl. b -Li 7-c PS 6-c X c ;

[0014] Wherein, LiX is one or more of LiCl, LiBr, and LiI, and MCl b It is one or more of MgCl2, CaCl2, SrCl2, BaCl2, ScCl3, YCl3, LaCl3, CeCl4, PrCl3, NdCl3, PmCl3, SmCl3, EuCl3, GdCl3, TbCl3, DyCl3, HoCl3, ErCl3, and TmCl3.

[0015] Using the above technical solution, the prepared sulfide solid electrolyte has the ability to effectively suppress metal dendrites, which can greatly reduce the short circuit risk of the prepared lithium-ion battery during high current density and long-term cycling. Moreover, the synthesis method is simple and has the potential for large-scale production.

[0016] Furthermore, in step 1), the grinding and mixing are carried out in an agate mortar for 3 to 10 minutes; the ball milling is carried out in a ball milling jar at a speed of 300 to 500 rpm for 10 to 20 hours, with a ball-to-material ratio of 15 to 20:1, and the ball milling process is carried out under inert gas protection.

[0017] Furthermore, the sintering temperature in step 1) is 400~600℃, and the heating rate during sintering is 3~8℃ / min. -1 The sintering time is 5 to 10 hours;

[0018] Furthermore, in step 2), the grinding and mixing are carried out in an agate mortar for 3 to 10 minutes; the ball milling is carried out in a ball milling jar at a speed of 100 to 200 rpm for 2 to 5 hours, with a ball-to-material ratio of 20 to 30:1, and the ball milling process is carried out under inert gas protection.

[0019] By employing the above technical solution and selecting chlorides with high reactivity with lithium metal, the limiting current density of the sulfide solid electrolyte can be effectively improved, thereby inhibiting the nucleation and growth of lithium metal within the electrolyte and enhancing the sulfide solid electrolyte's ability to suppress dendrite formation. The sulfide solid electrolyte provided by this invention, which combines high ionic conductivity and dendrite suppression capabilities, has a simple preparation process and can improve the rate performance and cycle life of solid-state batteries, demonstrating good practicality.

[0020] Thirdly, the present invention provides the application of the above-mentioned sulfide solid electrolyte in the preparation of all-solid-state lithium-ion batteries. Attached Figure Description

[0021] Figure 1 The limiting current density test curve of the product of Example 1;

[0022] Figure 2 The limiting current density test curve of the product of Example 2;

[0023] Figure 3 The limiting current density test curve of the product of Example 3;

[0024] Figure 4 The limiting current density test curve of the product of Example 4;

[0025] Figure 5 The limiting current density test curve of the product of Example 5;

[0026] Figure 6 The limiting current density test curve of the product of Example 6;

[0027] Figure 7 The limiting current density test curve of the product of Example 7;

[0028] Figure 8 The limiting current density test curve of the product of Example 8;

[0029] Figure 9 The limiting current density test curve of the product of Comparative Example 1 is shown.

[0030] Figure 10 Cyclic performance curves of the all-solid-state battery prepared in Example 1. Detailed Implementation

[0031] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Although the description of the present invention is presented in conjunction with preferred embodiments, this does not mean that the features of the invention are limited to these embodiments. On the contrary, the purpose of describing the invention in conjunction with embodiments is to cover other options or modifications that may be derived based on the claims of the present invention. To provide a deep understanding of the invention, many specific details will be included in the following description. The invention may also be implemented without using these details. Furthermore, to avoid confusion or obscuring the focus of the invention, some specific details will be omitted in the description. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0032] It should be noted that in this specification, similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0033] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0034] This application, through careful study of existing sulfide solid electrolytes, reveals significant differences in atomic structure and electronic configuration at grain boundaries compared to the overall properties of solid electrolyte grains (e.g., complex surface states and reduced band gaps). These differences result in higher electronic conductivity and lower lithium-ion conductivity, making them potential channels for electron leakage and playing a decisive role in the nucleation and growth of lithium dendrites. Therefore, this application aims to develop a sulfide solid electrolyte that effectively suppresses the growth of metal dendrites.

[0035] Example 1

[0036] This embodiment provides a 0.05BaCl2-Li 5.5 PS 4.5 Cl 1.5 The preparation method for sulfide solid electrolytes involves commercially available raw materials, and the preparation steps are as follows:

[0037] (1) Li 5.5 PS 4.5 Cl 1.5 Electrolyte preparation: Raw materials Li₂S, LiCl, and P₂S₅ (molar amounts of 20 mmol, 15 mmol, and 5 mmol, respectively) were weighed at a molar ratio of 2:1.5:0.5. After manual grinding and mixing in an agate mortar for 5 minutes, the mixed sample was placed in a ball mill jar filled with inert gas for ball milling. The ball-to-material ratio was 20:1, the ball mill speed was 300 rpm, and the milling time was 10 hours. The ball-milled product was then sintered under vacuum at a temperature of 500℃ and a heating rate of 5℃ / min. -1 The sintering time was 5 hours, yielding 2.67 g of Li. 5.5 PS 4.5 Cl 1.5 Electrolytes;

[0038] (2) 0.05BaCl2-Li 5.5 PS 4.5 Cl 1.5 Preparation of sulfide solid electrolyte: First, the Li obtained by sintering above... 5.5 PS 4.5 Cl 1.5 The electrolyte was manually crushed into powder in an agate mortar, and then BaCl2 and Li were weighed out in a mass ratio of 0.5:9.5. 5.5 PS 4.5 Cl 1.5(The raw materials used were 0.1g and 1.9g respectively). After manually grinding and mixing in an agate mortar for 5 minutes, the mixture was transferred to a ball mill jar filled with inert gas. The ball-to-material ratio was controlled at 30:1, the ball milling speed was 100 rpm, and the mixture was milled for 2 hours to obtain 2g of 0.05BaCl2-Li. 5.5 PS 4.5 Cl 1.5 Sulfide solid electrolyte.

[0039] Example 2

[0040] This embodiment provides a 0.1BaCl2-Li 5.5 PS 4.5 Cl 1.5 The preparation method for solid electrolytes, using commercially available raw materials, involves the following steps:

[0041] (1) Li 5.5 PS 4.5 Cl 1.5 Electrolyte preparation: Raw materials Li₂S, LiCl, and P₂S₅ (molar amounts of 20 mmol, 15 mmol, and 5 mmol, respectively) were weighed at a molar ratio of 2:1.5:0.5. After manual grinding and mixing in an agate mortar for 5 minutes, the mixed sample was placed in a ball mill jar filled with inert gas for ball milling. The ball-to-material ratio was 20:1, the ball mill speed was 300 rpm, and the milling time was 10 hours. The ball-milled product was then sintered under vacuum at a temperature of 500℃ and a heating rate of 5℃ / min. -1 The sintering time was 5 hours, yielding approximately 2.67 g of Li. 5.5 PS 4.5 Cl 1.5 Electrolytes;

[0042] (2) 0.1 BaCl2-Li 5.5 PS 4.5 Cl 1.5 Preparation of sulfide solid electrolyte: First, the Li obtained by sintering above... 5.5 PS 4.5 Cl 1.5 The electrolyte was manually crushed into powder in an agate mortar, and then BaCl2 and Li were weighed out in a mass ratio of 1:9. 5.5 PS 4.5 Cl 1.5 (The raw materials used were 0.2g and 1.8g respectively). After manually grinding and mixing in an agate mortar for 5 minutes, the mixture was transferred to a ball mill jar filled with inert gas. The ball-to-material ratio was controlled at 30:1, the ball milling speed was 100 rpm, and the mixture was milled for 2 hours to obtain 2g of 0.1BaCl2-Li. 5.5 PS 4.5 Cl1.5 Sulfide solid electrolyte.

[0043] Example 3

[0044] This embodiment provides a 0.15BaCl2-Li 5.5 PS 4.5 Cl 1.5 The preparation method for solid electrolytes, using commercially available raw materials, involves the following steps:

[0045] (1) Li 5.5 PS 4.5 Cl 1.5 Electrolyte preparation: Raw materials Li₂S, LiCl, and P₂S₅ (molar amounts of 20 mmol, 15 mmol, and 5 mmol, respectively) were weighed at a molar ratio of 2:1.5:0.5. After manual grinding and mixing in an agate mortar for 5 minutes, the mixed sample was placed in a ball mill jar filled with inert gas for ball milling. The ball-to-material ratio was 20:1, the ball mill speed was 300 rpm, and the milling time was 10 hours. The ball-milled product was then sintered under vacuum at a temperature of 500℃ and a heating rate of 5℃ / min. -1 The sintering time was 5 hours, yielding approximately 2.67 g of Li. 5.5 PS 4.5 Cl 1.5 Electrolytes;

[0046] (2) 0.15BaCl2-Li 5.5 PS 4.5 Cl 1.5 Preparation of sulfide solid electrolyte: First, the Li obtained by sintering above... 5.5 PS 4.5 Cl 1.5 The electrolyte was manually crushed into powder in an agate mortar, and then BaCl2 and Li were weighed out in a mass ratio of 1.5:8.5. 5.5 PS 4.5 Cl 1.5 (The raw materials used were 0.3g and 1.7g respectively). After manually grinding and mixing in an agate mortar for 5 minutes, the mixture was transferred to a ball mill jar filled with inert gas. The ball-to-material ratio was controlled at 30:1, the ball milling speed was 100 rpm, and the mixture was milled for 2 hours to obtain 2g of 0.15BaCl2-Li. 5.5 PS 4.5 Cl 1.5 Sulfide solid electrolyte.

[0047] Example 4

[0048] This embodiment provides a 0.2BaCl2-Li 5.5 PS 4.5Cl 1.5 The preparation method for solid electrolytes, using commercially available raw materials, involves the following steps:

[0049] (1) Li 5.5 PS 4.5 Cl 1.5 Electrolyte preparation: Raw materials Li₂S, LiCl, and P₂S₅ (molar amounts of 20 mmol, 15 mmol, and 5 mmol, respectively) were weighed at a molar ratio of 2:1.5:0.5. After manual grinding and mixing in an agate mortar for 5 minutes, the mixed sample was placed in a ball mill jar filled with inert gas for ball milling. The ball-to-material ratio was 20:1, the ball mill speed was 300 rpm, and the milling time was 10 hours. The ball-milled product was then sintered under vacuum at a temperature of 500℃ and a heating rate of 5℃ / min. -1 The sintering time was 5 hours, yielding approximately 2.67 g of Li. 5.5 PS 4.5 Cl 1.5 Electrolytes;

[0050] (2) 0.2BaCl2-Li 5.5 PS 4.5 Cl 1.5 Preparation of sulfide solid electrolyte: First, the Li obtained by sintering above... 5.5 PS 4.5 Cl 1.5 The electrolyte was manually crushed into powder in an agate mortar, and then BaCl2 and Li were weighed out in a mass ratio of 2:8. 5.5 PS 4.5 Cl 1.5 (The raw materials used were 0.4g and 1.6g respectively). After manually grinding and mixing in an agate mortar for 5 minutes, the mixture was transferred to a ball mill jar filled with inert gas. The ball-to-material ratio was controlled at 30:1, the ball milling speed was 100 rpm, and the mixture was ball milled for 2 hours to obtain 2g of 0.2BaCl2-Li. 5.5 PS 4.5 Cl 1.5 Sulfide solid electrolyte.

[0051] Example 5

[0052] This embodiment provides a 0.05LaCl3-Li 5.5 PS 4.5 Cl 1.5 The preparation method for solid electrolytes, using commercially available raw materials, involves the following steps:

[0053] (1) Li 5.5 PS 4.5 Cl 1.5Electrolyte preparation: Raw materials Li₂S, LiCl, and P₂S₅ (molar amounts of 20 mmol, 15 mmol, and 5 mmol, respectively) were weighed at a molar ratio of 2:1.5:0.5. After manual grinding and mixing in an agate mortar for 5 minutes, the mixed sample was placed in a ball mill jar filled with inert gas for ball milling. The ball-to-material ratio was 20:1, the ball mill speed was 300 rpm, and the milling time was 10 hours. The ball-milled product was then sintered under vacuum at a temperature of 500℃ and a heating rate of 5℃ / min. -1 The sintering time was 5 hours, yielding approximately 2.67 g of Li. 5.5 PS 4.5 Cl 1.5 Electrolytes;

[0054] (2) 0.05LaCl3-Li 5.5 PS 4.5 Cl 1.5 Preparation of sulfide solid electrolyte: First, the Li obtained by sintering above... 5.5 PS 4.5 Cl 1.5 The electrolyte was manually crushed into powder in an agate mortar, and then LaCl3 and Li were weighed out in a mass ratio of 0.5:9.5. 5.5 PS 4.5 Cl 1.5 (The raw materials used were 0.1g and 1.9g respectively). After manually grinding and mixing in an agate mortar for 5 minutes, the mixture was transferred to a ball mill jar filled with inert gas. The ball-to-material ratio was controlled at 30:1, the ball milling speed was 150 rpm, and the mixture was milled for 1.5 hours to obtain 2g of 0.05LaCl3-Li. 5.5 PS 4.5 Cl 1.5 Sulfide solid electrolyte.

[0055] Example 6

[0056] This embodiment provides a 0.1LaCl3-Li 5.5 PS 4.5 Cl 1.5 The preparation method for solid electrolytes, using commercially available raw materials, involves the following steps:

[0057] (1) Li 5.5 PS 4.5 Cl 1.5Electrolyte preparation: Raw materials Li₂S, LiCl, and P₂S₅ (molar amounts of 20 mmol, 15 mmol, and 5 mmol, respectively) were weighed at a molar ratio of 2:1.5:0.5. After manual grinding and mixing in an agate mortar for 5 minutes, the mixed sample was placed in a ball mill jar filled with inert gas for ball milling. The ball-to-material ratio was 20:1, the ball mill speed was 300 rpm, and the milling time was 10 hours. The ball-milled product was then sintered under vacuum at a temperature of 500℃ and a heating rate of 5℃ / min. -1 The sintering time was 5 hours, yielding approximately 2.67 g of Li. 5.5 PS 4.5 Cl 1.5 Electrolytes;

[0058] (2) 0.1LaCl3-Li 5.5 PS 4.5 Cl 1.5 Preparation of sulfide solid electrolyte: First, the Li obtained by sintering above... 5.5 PS 4.5 Cl 1.5 The electrolyte was manually crushed into powder in an agate mortar, and then LaCl3 and Li were weighed out in a mass ratio of 1:9. 5.5 PS 4.5 Cl 1.5 (The raw materials used were 0.2g and 1.8g respectively). After manually grinding and mixing in an agate mortar for 5 minutes, the mixture was transferred to a ball mill jar filled with inert gas. The ball-to-material ratio was controlled at 30:1, the ball milling speed was 150 rpm, and the mixture was milled for 1.5 hours to obtain 2g of 0.1LaCl3-Li. 5.5 PS 4.5 Cl 1.5 Sulfide solid electrolyte.

[0059] Example 7

[0060] This embodiment provides a 0.15LaCl3-Li 5.5 PS 4.5 Cl 1.5 The preparation method for solid electrolytes, using commercially available raw materials, involves the following steps:

[0061] (1) Li 5.5 PS 4.5 Cl 1.5Electrolyte preparation: Raw materials Li₂S, LiCl, and P₂S₅ (molar amounts of 20 mmol, 15 mmol, and 5 mmol, respectively) were weighed at a molar ratio of 2:1.5:0.5. After manual grinding and mixing in an agate mortar for 5 minutes, the mixed sample was placed in a ball mill jar filled with inert gas for ball milling. The ball-to-material ratio was 20:1, the ball mill speed was 300 rpm, and the milling time was 10 hours. The ball-milled product was then sintered under vacuum at a temperature of 500℃ and a heating rate of 5℃ / min. -1 The sintering time was 5 hours, yielding approximately 2.67 g of Li. 5.5 PS 4.5 Cl 1.5 Electrolytes;

[0062] (2) 0.15LaCl3-Li 5.5 PS 4.5 Cl 1.5 Preparation of sulfide solid electrolyte: First, the Li obtained by sintering above... 5.5 PS 4.5 Cl 1.5 The electrolyte was manually crushed into powder in an agate mortar, and then LaCl3 and Li were weighed out in a mass ratio of 1.5:8.5. 5.5 PS 4.5 Cl 1.5 (The raw materials used were 0.3g and 1.7g respectively). After manually grinding and mixing in an agate mortar for 5 minutes, the mixture was transferred to a ball mill jar filled with inert gas. The ball-to-material ratio was controlled at 30:1, the ball milling speed was 150 rpm, and the mixture was milled for 1.5 hours to obtain 2g of 0.15LaCl3-Li. 5.5 PS 4.5 Cl 1.5 Sulfide solid electrolyte.

[0063] Example 8

[0064] This embodiment provides a 0.2LaCl3-Li 5.5 PS 4.5 Cl 1.5 The preparation method for solid electrolytes, using commercially available raw materials, involves the following steps:

[0065] (1) Li 5.5 PS 4.5 Cl 1.5Electrolyte preparation: Raw materials Li₂S, LiCl, and P₂S₅ (molar amounts of 20 mmol, 15 mmol, and 5 mmol, respectively) were weighed at a molar ratio of 2:1.5:0.5. After manual grinding and mixing in an agate mortar for 5 minutes, the mixed sample was placed in a ball mill jar filled with inert gas for ball milling. The ball-to-material ratio was 20:1, the ball mill speed was 300 rpm, and the milling time was 10 hours. The ball-milled product was then sintered under vacuum at a temperature of 500℃ and a heating rate of 5℃ / min. -1 The sintering time was 5 hours, yielding approximately 2.67 g of Li. 5.5 PS 4.5 Cl 1.5 Electrolytes;

[0066] (2) 0.2LaCl3-Li 5.5 PS 4.5 Cl 1.5 Preparation of sulfide solid electrolyte: First, the Li obtained by sintering above... 5.5 PS 4.5 Cl 1.5 The electrolyte was manually crushed into powder in an agate mortar, and then LaCl3 and Li were weighed out in a mass ratio of 2:8. 5.5 PS 4.5 Cl 1.5 (The raw materials used were 0.4g and 1.6g respectively). After manually grinding and mixing in an agate mortar for 5 minutes, the mixture was transferred to a ball mill jar filled with inert gas. The ball-to-material ratio was controlled at 30:1, the ball milling speed was 150 rpm, and the mixture was milled for 1.5 hours to obtain 2g of 0.2LaCl3-Li. 5.5 PS 4.5 Cl 1.5 Sulfide solid electrolyte.

[0067] Example 9

[0068] This embodiment provides a 0.1CaCl2-Li 5.5 PS 4.5 Cl 1.5 The preparation method for solid electrolytes, using commercially available raw materials, involves the following steps:

[0069] (1) Li 5.5 PS 4.5 Cl 1.5Electrolyte preparation: Raw materials Li₂S, LiCl, and P₂S₅ (molar amounts of 20 mmol, 15 mmol, and 5 mmol, respectively) were weighed at a molar ratio of 2:1.5:0.5. After manual grinding and mixing in an agate mortar for 5 minutes, the mixed sample was placed in a ball mill jar filled with inert gas for ball milling. The ball-to-material ratio was 20:1, the ball mill speed was 300 rpm, and the milling time was 10 hours. The ball-milled product was then sintered under vacuum at a temperature of 500℃ and a heating rate of 5℃ / min. -1 The sintering time was 5 hours, yielding approximately 2.67 g of Li. 5.5 PS 4.5 Cl 1.5 Electrolytes;

[0070] (2) 0.1CaCl2-Li 5.5 PS 4.5 Cl 1.5 Preparation of sulfide solid electrolyte: First, the Li obtained by sintering above... 5.5 PS 4.5 Cl 1.5 The electrolyte was manually crushed into powder in an agate mortar, and then CaCl2 and Li were weighed out in a mass ratio of 1:9. 5.5 PS 4.5 Cl 1.5 (The raw materials used were 0.2g and 1.8g respectively). After manually grinding and mixing in an agate mortar for 5 minutes, the mixture was transferred to a ball mill jar filled with inert gas. The ball-to-material ratio was controlled at 30:1, the ball milling speed was 150 rpm, and the mixture was milled for 1.5 hours to obtain 2g of 0.1CaCl2-Li. 5.5 PS 4.5 Cl 1.5 Sulfide solid electrolyte.

[0071] Example 10

[0072] This embodiment provides a 0.1SmCl3-Li 5.5 PS 4.5 Cl 1.5 The preparation method for solid electrolytes, using commercially available raw materials, involves the following steps:

[0073] (1) Li 5.5 PS 4.5 Cl 1.5Electrolyte preparation: Raw materials Li₂S, LiCl, and P₂S₅ (molar amounts of 20 mmol, 15 mmol, and 5 mmol, respectively) were weighed at a molar ratio of 2:1.5:0.5. After manual grinding and mixing in an agate mortar for 5 minutes, the mixed sample was placed in a ball mill jar filled with inert gas for ball milling. The ball-to-material ratio was 20:1, the ball mill speed was 300 rpm, and the milling time was 10 hours. The ball-milled product was then sintered under vacuum at a temperature of 500℃ and a heating rate of 5℃ / min. -1 The sintering time was 5 hours, yielding approximately 2.67 g of Li. 5.5 PS 4.5 Cl 1.5 Electrolytes;

[0074] (2) 0.1SmCl3-Li 5.5 PS 4.5 Cl 1.5 Preparation of sulfide solid electrolyte: First, the Li obtained by sintering above... 5.5 PS 4.5 Cl 1.5 The electrolyte was manually crushed into powder in an agate mortar, and then SmCl3 and Li were weighed out in a mass ratio of 1:9. 5.5 PS 4.5 Cl 1.5 (The raw materials used were 0.2g and 1.8g respectively). After manually grinding and mixing in an agate mortar for 5 minutes, the mixture was transferred to a ball mill jar filled with inert gas. The ball-to-material ratio was controlled at 30:1, the ball milling speed was 150 rpm, and the mixture was milled for 1.5 hours to obtain 2g of 0.1SmCl3-Li. 5.5 PS 4.5 Cl 1.5 Sulfide solid electrolyte.

[0075] Example 11

[0076] This embodiment provides a 0.1YCl3-Li 5.5 PS 4.5 Cl 1.5 The preparation method for solid electrolytes, using commercially available raw materials, involves the following steps:

[0077] (1) Li 5.5 PS 4.5 Cl 1.5Electrolyte preparation: Raw materials Li₂S, LiCl, and P₂S₅ (molar amounts of 20 mmol, 15 mmol, and 5 mmol, respectively) were weighed at a molar ratio of 2:1.5:0.5. After manual grinding and mixing in an agate mortar for 5 minutes, the mixed sample was placed in a ball mill jar filled with inert gas for ball milling. The ball-to-material ratio was 20:1, the ball mill speed was 300 rpm, and the milling time was 10 hours. The ball-milled product was then sintered under vacuum at a temperature of 500℃ and a heating rate of 5℃ / min. -1 The sintering time was 5 hours, yielding approximately 2.67 g of Li. 5.5 PS 4.5 Cl 1.5 Electrolytes;

[0078] (2) 0.1YCl3-Li 5.5 PS 4.5 Cl 1.5 Preparation of sulfide solid electrolyte: First, the Li obtained by sintering above... 5.5 PS 4.5 Cl 1.5 The electrolyte was manually crushed into powder in an agate mortar, and then YCl3 and Li were weighed out in a mass ratio of 1:9. 5.5 PS 4.5 Cl 1.5 (The raw materials used were 0.2g and 1.8g respectively). After manually grinding and mixing in an agate mortar for 5 minutes, the mixture was transferred to a ball mill jar filled with inert gas. The ball-to-material ratio was controlled at 30:1, the ball milling speed was 150 rpm, and the mixture was milled for 1.5 hours to obtain 2g of 0.1YCl3-Li. 5.5 PS 4.5 Cl 1.5 Sulfide solid electrolyte.

[0079] Example 12

[0080] This embodiment provides a method for preparing 0.1BaCl2-Li6PS5Cl solid electrolyte. All raw materials are commercially available. The preparation steps are as follows:

[0081] (1) Preparation of Li6PS5Cl electrolyte: Li2S, LiCl, and P2S5 (molar amounts of 25 mmol, 0.5 mmol, and 1 mmol, respectively) were weighed in a molar ratio of 2.5:0.5:1. The mixture was manually ground and mixed in an agate mortar for 5 minutes. The resulting sample was then placed in a ball mill jar filled with inert gas for ball milling. The ball-to-material ratio was 20:1, the ball mill speed was 300 rpm, and the milling time was 10 hours. The ball-milled product was then sintered under vacuum at a temperature of 600℃ and a heating rate of 1.5℃ / min.-1 The sintering time was 10 hours, yielding approximately 2.68 g of Li6PS5Cl electrolyte;

[0082] (2) Preparation of 0.1BaCl2-Li6PS5Cl sulfide solid electrolyte: First, the Li6PS5Cl electrolyte obtained by sintering above was manually crushed into powder in an agate mortar. Then, BaCl2 and Li6PS5Cl were weighed at a mass ratio of 1:9 (the mass amounts of raw materials were 0.2g and 1.8g, respectively). After manually grinding and mixing in an agate mortar for 5 minutes, the mixture was transferred to a ball mill jar filled with inert gas. The ball-to-material ratio was controlled at 30:1, the ball milling speed was 100rpm, and the mixture was ball milled for 2 hours to obtain 2g of 0.1BaCl2-Li6PS5Cl sulfide solid electrolyte.

[0083] Comparative Example 1

[0084] This comparative example provides a Li 5.5 PS 4.5 Cl 1.5 The preparation method for solid electrolytes, using commercially available raw materials, involves the following steps:

[0085] Raw materials Li₂S, LiCl, and P₂S₅ were weighed according to a molar ratio of 2:1.5:0.5 (molar amounts of 20 mmol, 15 mmol, and 5 mmol, respectively). After manual grinding and mixing in an agate mortar for 5 minutes, the mixed sample was placed in a ball mill jar filled with inert gas for ball milling at a ball-to-material ratio of 20:1, a mill speed of 300 rpm, and a milling time of 10 hours. The resulting product was then sintered under vacuum at a temperature of 500℃ and a heating rate of 5℃ / min. -1 A heat treatment time of 5 hours yields approximately 2.67g of Li. 5.5 PS 4.5 Cl 1.5 Solid electrolyte.

[0086] Comparative Example 2

[0087] This comparative example provides a method for preparing Li6PS5Cl solid electrolyte. All raw materials are commercially available. The preparation steps are as follows:

[0088] Raw materials Li₂S, LiCl, and P₂S₅ were weighed according to a molar ratio of 2.5:0.5:1 (molar amounts of 25 mmol, 0.5 mmol, and 1 mmol, respectively). After manual grinding and mixing in an agate mortar for 5 minutes, the mixed sample was placed in a ball mill jar filled with inert gas for ball milling at a ball-to-material ratio of 20:1, a ball mill speed of 300 rpm, and a milling time of 10 hours. The resulting product was then sintered under vacuum at a temperature of 600℃ and a heating rate of 1.5℃ / min. -1 Approximately 2.68g of Li6PS5Cl solid electrolyte can be obtained by holding the solution at a temperature of 10 hours.

[0089] Application Example 1

[0090] This embodiment provides a method for preparing an all-solid-state lithium-ion battery, and all raw materials used in the preparation are commercially available. The preparation method includes the following steps:

[0091] (1) Preparation of positive electrode powder: LiCoO2 positive electrode active material, 0.1 BaCl2-Li sulfide solid electrolyte prepared in Example 2, and other materials were mixed. 5.5 PS 4.5 Cl 1.5 Conductive additive VGCF is mixed uniformly in a mass ratio of 70:30:3;

[0092] (2) Preparation of negative electrode: Under the protection of argon atmosphere, Li metal is cut into circular pieces with a diameter of 1 cm;

[0093] (3) Assembly of all-solid-state lithium-ion batteries: First, the 0.1 BaCl2-Li prepared in Example 2 was assembled... 5.5 PS 4.5 Cl 1.5 The sulfide solid electrolyte is pressed into a dense disc in the battery. Then, the positive electrode powder obtained in step (1) is placed on one side of the solid electrolyte. Pressure is applied to make the positive electrode powder adhere evenly to the surface of the solid electrolyte. Finally, the negative electrode sheet obtained in step (2) is placed on the other side of the solid electrolyte. Pressure is applied to make the negative electrode sheet adhere tightly to the surface of the solid electrolyte, and thus an all-solid-state lithium-ion battery is obtained.

[0094] The sulfide solid electrolyte described in this invention only serves to improve ionic conductivity in the positive electrode and does not provide actual capacity.

[0095] Critical current density test principle: Using a symmetrical battery (such as a lithium metal symmetrical battery), the current density is increased stepwise in alternating directions (dashed line, corresponding to...). Figures 1-9 (Right ordinate), observe the battery voltage change (solid line, corresponding to...) Figures 1-9 (The left ordinate of the graph). When the voltage suddenly drops to zero, the corresponding current density is the critical current density.

[0096] Figures 1-4 The aBaCl2-Li obtained in Examples 1, 2, 3, and 4 are respectively. 5.5 PS 4.5 Cl 1.5 (a = 0.05, 0.1, 0.15, 0.2) Limiting current density curves of sulfide solid electrolytes. The results show that when a = 0.1, 0.1 BaCl₂-Li 5.5 PS 4.5 Cl 1.5 The electrolyte exhibits the highest limiting current density, reaching 4.1 mA cm⁻¹. -2 .

[0097] Figures 5-8 The aLaCl3-Li obtained in Examples 5, 6, 7 and 8 are respectively. 5.5 PS 4.5 Cl 1.5 (a = 0.05, 0.1, 0.15, 0.2) Limiting current density curves of sulfide solid electrolytes. The results show that when a = 0.1, 0.1 LaCl3-Li 5.5 PS 4.5 Cl 1.5 The electrolyte exhibits the highest limiting current density, reaching 4.0 mA cm⁻¹. -2 .

[0098] Figure 9 The Li obtained in Comparative Example 1 5.5 PS 4.5 Cl 1.5 Limiting current density curves of sulfide solid electrolytes. To further highlight the effects of the present invention, Table 1 summarizes the room temperature ionic conductivity and limiting current density data of different embodiments and comparative examples of the present invention. As shown in Table 1, the addition of BaCl2, LaCl3, CaCl2, SmCl3, and YCl3 can improve the ionic conductivity of the sulfide electrolyte to a certain extent and significantly increase the limiting current density of the electrolyte. This indicates that the invention can improve the dendrite suppression ability of the sulfide electrolyte, enabling the solid-state battery to tolerate higher currents.

[0099] Table 1. Room temperature ionic conductivity and limiting current of different embodiments and comparative examples

[0100]

[0101] In summary, the sulfide solid electrolyte of this invention exhibits high room-temperature ionic conductivity and excellent dendrite suppression capability, making it suitable for high-rate and long-life all-solid-state battery systems. This invention addresses the problem of significant differences in atomic structure and electronic configuration at grain boundaries in sulfide solid electrolytes (e.g., complex surface states and reduced band gaps). By selecting chloride materials with low electronic conductivity to modify the grain boundaries of the sulfide solid electrolyte, the electron leakage channels are blocked, thereby suppressing the nucleation and growth of lithium dendrites. The preparation method of the sulfide solid electrolyte of this invention is simple, feasible, and has good practicality.

[0102] Figure 10 This figure shows the cycle performance curves of the all-solid-state lithium metal battery in Application Example 1 of this invention. The figure includes the charge specific capacity (white circles), discharge specific capacity (gray circles), and coulombic efficiency (solid squares) of the all-solid-state battery at different cycle numbers, where coulombic efficiency = (discharge specific capacity / charge specific capacity) × 100%. Since the initial charge specific capacity is slightly higher than the discharge specific capacity, the first white circle and gray circle from the left in the figure do not overlap, and the coulombic efficiency (i.e., the first solid square from the left) is less than 100%. From the second cycle onwards, the charge specific capacity is almost equal to the discharge specific capacity, therefore the white circle and gray circle overlap, and the coulombic efficiency is also close to 100%. Figure 10 As can be seen, all-solid-state lithium-ion batteries can provide 130mA hg. -1 The reversible specific capacity and almost no capacity decay after 100 stable cycles prove that the sulfide solid electrolyte provided by this invention can not only provide the high ionic conductivity required for the operation of all-solid-state lithium-ion batteries, but also maintain compatibility with the positive electrode active material and lithium metal, thereby ensuring the stable cycling of solid-state lithium-ion batteries and further verifying its good practicality.

[0103] While the present invention has been illustrated and described with reference to certain preferred embodiments, those skilled in the art should understand that the above description is a further detailed explanation of the invention in conjunction with specific embodiments, and should not be construed as limiting the specific implementation of the invention to these descriptions. Various changes in form and detail can be made by those skilled in the art, including several simple deductions or substitutions, without departing from the spirit and scope of the invention.

Claims

1. A sulfide solid electrolyte that inhibits dendrite growth, characterized in that: The general chemical formula of this sulfide solid electrolyte is aMCl. b -Li 7-c PS 6-c X c Where M is one or more of Ca, Ba, Y, La, Ce, Nd, Sm, Tb, Ho, and Er, and b depends on the chemical valence state of element M; 0.01 ≤ a ≤ 0.4 indicates MCl b It accounts for 1-40% of the total mass of the sulfide solid electrolyte; X is one or more of Cl, Br, and I; 1 ≤ c ≤ 2; and the sulfide solid electrolyte is prepared by the following steps. 1) Electrolyte Li 7-c PS 6-c X c Preparation: Based on the value of c, raw materials Li₂S, LiX, and P₂S₅ were weighed in molar proportions, ground and mixed, and then ball-milled. The ball-milled product was then sintered under vacuum and naturally cooled to room temperature to obtain the electrolyte Li. 7-c PS 6-c X c ; 2) aMCl b -Li 7-c PS 6-c X c Preparation: Based on the value of a, weigh MCl according to the mass ratio. b and Li 7-c PS 6-c X c After grinding and mixing, the mixture is ball-milled to obtain the sulfide solid electrolyte aMCl. b -Li 7-c PS 6-c X c ; Wherein, LiX is one or more of LiCl, LiBr, and LiI, and MCl b It is one or more of CaCl2, BaCl2, YCl3, LaCl3, CeCl4, NdCl3, SmCl3, TbCl3, HoCl3 and ErCl3; In step 1), grinding and mixing are carried out in an agate mortar for 3-10 minutes; ball milling is carried out in a ball mill jar at a speed of 300-500 rpm for 10-20 hours with a ball-to-material ratio of 15-20:1, and the ball milling process is conducted under inert gas protection; the sintering temperature is 400-600°C, and the heating rate during sintering is 3-8°C / min. -1 The sintering time is 5 to 10 hours; In step 2), grinding and mixing are carried out in an agate mortar for 3 to 10 minutes; ball milling is carried out in a ball milling jar at a speed of 100 to 200 rpm for 2 to 5 hours with a ball-to-material ratio of 20 to 30:1, and the ball milling process is carried out under inert gas protection.

2. The sulfide solid electrolyte for inhibiting dendrite growth as described in claim 1, characterized in that: 0.05≤a≤0.2。 3. The sulfide solid electrolyte for inhibiting dendrite growth as described in claim 1, characterized in that: M can be Ca, Sm, Y, La, or Ba.

4. A sulfide solid electrolyte for inhibiting dendrite growth as described in claim 1, characterized in that: 1≤c≤1.5。 5. The application of the sulfide solid electrolyte for inhibiting dendrite growth as described in any one of claims 1 to 4 in the preparation of all-solid-state lithium-ion batteries.

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