3D printed soft-pack batteries based on composite solid-state electrolyte design

Abstract

The present invention discloses a 3D-printed soft-pack battery based on a composite solid-state electrolyte design, relating to the technical field of solid-state batteries. The composite solid-state electrolyte (M‑CSE) comprises the following components: LPSCl and LSiSnPSBrO. The M‑CSE structure of the present invention ensures that during electrolyte decomposition, internal expansion stress generates a compressive force on adjacent electrolytes, effectively inhibiting further decomposition. The self-limiting behavior helps form a thin and dense interface layer, significantly reducing interfacial impedance and preventing lithium dendrite penetration. The decomposition of LSiSnPSBrO not only produces metastable electrolyte particles but also leads to the formation of a lithiophilic Li‑Si / Sn alloy. The alloy acts as a lithiophilic seed in the M‑CSE, enhancing lithium kinetics and regulating lithium nucleation, thereby leading to uniform lithium deposition. The M‑CSE interface structure helps balance the electric field and optimize lithium deposition, significantly improving the overall performance of the battery.

Description

Technical Field

[0001] The present invention relates to the technical field of all-solid-state batteries. Specifically, the present invention relates to a composite solid-state electrolyte and a preparation method thereof, which are specifically applied to all-solid-state batteries. The present invention also relates to an all-solid-state battery containing the composite solid-state electrolyte and a preparation method thereof, and to a 3D-printed soft-pack battery containing the composite solid-state electrolyte and a preparation method thereof. Background Art

[0002] Although the combination of sulfide solid electrolyte and lithium metal anode has great potential in improving battery energy density and safety, it still faces many technical challenges.

[0003] First, interfacial chemical instability is a key issue. Sulfide electrolytes are prone to uncontrollable chemical reactions when in contact with lithium metal, generating non-conductive byproducts such as Li2S and Li3P. This increases interfacial impedance and severely impacts the battery's ion transport and overall electrochemical performance. Furthermore, the high activity of lithium metal further exacerbates these side reactions, making it difficult to maintain interfacial stability. Especially under high-voltage operating conditions, the electrolyte may be oxidized or decomposed, impacting cycle life.

[0004] Another significant problem is the growth of lithium dendrites. Although solid electrolytes can theoretically inhibit the formation of dendrites, at high current densities, lithium dendrites may still grow and pierce the electrolyte, causing internal short circuits and seriously affecting the safety of the battery. Lithium metal undergoes large volume changes during the deposition and stripping process, which can lead to poor interfacial contact with the sulfide electrolyte, resulting in voids and unevenness, further exacerbating dendrite growth and interfacial failure. In addition, the electrochemical window of sulfide solid electrolytes is narrow. When the battery operates at a higher voltage, the electrolyte is prone to oxidation or reduction reactions, producing irreversible byproducts. This limits the pairing of this type of electrolyte with high-voltage positive electrode materials, affecting the energy density and operating stability of the battery.

[0005] Finally, in terms of manufacturing, sulfide solid electrolytes are very sensitive to humidity. When exposed to air, they react with water to produce harmful hydrogen sulfide gas, requiring a strict anhydrous and oxygen-free environment for material preparation and processing. In addition, improving the interfacial contact between lithium metal and sulfide electrolytes usually requires complex processes such as interface modification, protective layer design, and pressure control, which increases the difficulty and cost of manufacturing.

[0006] Overall, these issues collectively limit the practical application of sulfide solid electrolyte and lithium metal anode systems, requiring further optimization of materials and interface engineering. Chemical reactions easily occur at the interface between the solid electrolyte and the lithium metal anode, leading to interface instability and the formation of a high-impedance interface layer, which affects the overall performance of the battery. Furthermore, solid electrolytes have a weak ability to suppress lithium dendrites at high current densities, making them incapable of meeting the requirements of high-rate charge and discharge.

[0007] In light of this, the present invention aims to design a novel multifunctional composite solid-state electrolyte prepared by finely mixing multiple different solid-state electrolytes. This composite solid-state electrolyte not only retains the advantages of each material individually, but also, through their synergistic effect, improves the ability to suppress lithium dendrites and improves interfacial stability. Experimental results show that lithium batteries using this mixed electrolyte exhibit excellent stability and long cycle performance under high current density conditions, maintaining a high capacity after multiple cycles. Summary of the Invention

[0008] In order to solve the above technical problems, the present invention provides a composite solid electrolyte and an all-solid-state battery and a 3D-printed soft-pack battery containing the same. The composite solid electrolyte not only retains the respective advantages of the two materials, but also improves the inhibition ability of lithium dendrites and interface stability through synergistic effects, so that the lithium battery exhibits excellent stability and long cycle performance under high current density conditions, thereby solving the corresponding technical problems raised in the above background technology.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows: In a first aspect, the present invention relates to a composite solid electrolyte, and the composite solid electrolyte (M-CSE) includes the following components: LPSCl, LSiSnPSBrO.

[0010] Preferably, the mass fraction of the LSiSnPSBrO is 10wt%-30wt%.

[0011] Preferably, the mass fraction of the LSiSnPSBrO is 10 wt %.

[0012] Preferably, the LPSCl is Li 5.3 PS 4.3 Cl 1.7 , the LSiSnPSBrO is Li 9.54 [Si 0.5 Sn 0.5 ]PSBrO.

[0013] In a second aspect, the present invention relates to a method for preparing a composite solid electrolyte. The preparation method is as follows: LPSCl and LSiSnPSBrO powders are manually ground in an agate mortar at a desired mass ratio for 10 minutes or ball-milled in a planetary ball mill at a desired mass ratio for 10 minutes to obtain the composite solid electrolyte (M-CSE).

[0014] In a third aspect, the present invention relates to an all-solid-state battery, comprising a negative electrode, an M-CSE layer, and a positive electrode, wherein the M-CSE layer is made of a composite solid electrolyte.

[0015] Preferably, the positive electrode is a composite positive electrode, and the preparation method of the composite positive electrode is: the positive electrode material is obtained by ball milling LCO, VGCF and LPSCl with a mass ratio of 60:5:35 at a rotation speed of 100 rpm for 0.2 h.

[0016] Preferably, the LPSCl is Li6PS5Cl.

[0017] Preferably, the preparation method of the Li6PS5Cl is as follows: Li2S, P2S5 and LiCl are mixed in a molar ratio of 5:1:2, the rotation speed is set to 600 rpm, and ball milling is performed for 12 hours; sintering is performed at 550°C for 12 hours under an argon atmosphere at a heating rate of 5°C / min, and finally crushing to obtain Li6PS5Cl.

[0018] As an example, there is a SE layer between the positive electrode and the M-CSE layer, and the SE layer is composed of Li6PS5Cl or Li 5.3 PS 4.3 Cl 1.7 Made.

[0019] In a fourth aspect, the present invention relates to a method for preparing an all-solid-state battery, the method comprising the following steps: (1) adding 60 mg of Li6PS5Cl or Li 5.3 PS 4.3 Cl 1.7 The SE layer was formed by pressing the pellets into discs with a diameter of 10 mm under a pressure of 124 MPa.

[0020] (2) Place 10 mg of the composite positive electrode on one side of the SE layer and press it at a pressure of 496 MPa for 2 minutes to ensure that the two are tightly bonded.

[0021] (3) 20 mg of pre-synthesized M-CSE was placed on the other side of the SE layer and pressed at a pressure of 868 MPa for 2 min to form an M-CSE layer, which was tightly bonded to the SE layer.

[0022] (4) A 10 mm lithium sheet is placed on the other side of the M-CSE layer. The lithium sheet serves as the lithium metal negative electrode, and the all-solid-state battery is assembled.

[0023] The M-CSE material is the composite solid electrolyte.

[0024] In a fifth aspect, the present invention relates to a method for preparing a 3D printed soft-pack battery, the preparation method comprising the following steps: step S1, taking a certain amount of composite positive electrode, negative electrode, electrolyte and M-CSE material; adding 8% by mass of nitrile rubber (NBR) to the composite positive electrode, electrolyte and M-CSE respectively to prepare positive electrode printing slurry, electrolyte printing slurry and M-CSE printing slurry.

[0025] Step S2: Place the positive electrode printing slurry, electrolyte printing slurry and M-CSE printing slurry in multiple nozzles of the 3D printer respectively, and print M-CSE, electrolyte and composite positive electrode on the negative electrode in sequence by switching the nozzles.

[0026] Step S3: Add aluminum-plastic film to the outside of the printed battery structure to complete the packaging.

[0027] Step S4: isostatically compact the formed product at 2 MP to obtain a 3D printed soft-pack battery.

[0028] The preparation method of the composite positive electrode is as follows: the positive electrode material is obtained by ball milling LCO, VGCF and LPSCl with a mass ratio of 60:5:35 at a rotation speed of 100 rpm for 0.2 h.

[0029] The negative electrode is a copper-lithium composite strip, wherein the thickness of the lithium strip is 20 μm and the thickness of the copper strip is 20 μm.

[0030] The electrolyte is Li 5.3 PS 4.3 Cl 1.7 .

[0031] The M-CSE material is the composite solid electrolyte.

[0032] Compared with the prior art, the present invention has the following beneficial effects: 1. One of the core aspects of the technical solution of the present invention is that the presence of an M-CSE layer in the battery of the present invention can effectively improve the stability and reliability of battery performance, especially under conditions of high current density and long cycle life. The M-CSE layer inherits the advantages of its high chemical stability and good interfacial affinity. This not only protects the electrode material from corrosive side reactions but also provides a smooth channel for lithium ion conduction. In addition, local interfacial passivation occurs, thereby alleviating the stress caused by volume change and maintaining the compactness and stability of the interface. The interfacial passivation effect further inhibits the decomposition of the electrolyte and effectively slows the growth of lithium dendrites. In addition, the lithium ion conductive material (such as Li-Sn alloy) in the M-CSE layer facilitates uniform lithium deposition and ensures a uniform electric field distribution, thereby guiding the stable nucleation and growth of lithium. Therefore, through the dual regulation mechanism of physical isolation and chemical balance, the M-CSE layer can effectively inhibit the growth of lithium dendrites and prevent them from penetrating the solid electrolyte. The introduction of the M-CSE layer in the battery significantly improves its critical current density (CCD), enabling it to exhibit excellent electrochemical stability even at high current densities. Through the combined effects of physical barrier properties and chemical stability, the M-CSE layer provides substantial protection for the battery, thereby improving its overall performance and extending its service life.

[0033] 2. In the technical solution of the present invention, the second core lies in: the M-CSE structure in the present invention is designed to enhance the interfacial stability between the lithium metal anode and the sulfide SSE. This structure ensures uniform lithium deposition and suppresses the formation of lithium dendrites, making it effective under the working conditions of all-solid-state batteries. More importantly, this structure was successfully realized in 3D-printed sulfide-based solid-state batteries. Generally, sulfide electrolytes (such as LPSCl and Li 9.54 [Si 0.5 Sn 0.5 ]PSBrO) is not completely consistent with the thermodynamic stability of lithium metal. When used independently, these electrolytes tend to form two suboptimal interfaces, namely SEI and MCI. This not only leads to interfacial degradation, but also allows lithium dendrites to penetrate, ultimately affecting battery performance. However, the M-CSE structure exhibits excellent interfacial stability, and its excellent performance is attributed to the internal inhibition mechanism. During the decomposition of the electrolyte, the internal expansion stress exerts a compressive force on the adjacent electrolyte, effectively inhibiting further decomposition. This self-limiting behavior helps to form a thin and dense interfacial layer, significantly reducing the interfacial impedance and preventing lithium dendrite penetration. Li 9.54 [Si 0.5 Sn 0.5The decomposition of PSBrO not only produces metastable electrolyte particles but also leads to the formation of lithiophilic Li-Si / Sn alloys. These alloys act as lithiophilic seeds in the M-CSE, enhancing lithium kinetics and regulating lithium nucleation, resulting in uniform lithium deposition. This dynamically stable M-CSE interface structure helps balance the electric field and optimize lithium deposition, significantly improving the overall battery performance.

[0034] 3. The advantages of the present invention are: thanks to the M-CSE structure in the present invention, by exploring the high adaptability of sulfide-based SSE and combining the unique advantages of different electrolyte types, and combining advanced design with 3D printing technology, it opens up new possibilities for developing next-generation solid-state electrolyte materials to meet the commercial needs of all-solid-state batteries. This simple and efficient 3D printing manufacturing method has laid a solid foundation for the large-scale production and application of all-solid-state batteries, and provides a key reference for the future development of battery technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1-Figure 3 Schematic diagram of the interface of batteries with different configurations, where Figure 1 For interfacially unstable cells, where the growing interfacial layer leads to a significant overpotential, Figure 2 For batteries with SEI interface, there is lithium dendrite penetration. Figure 3 This is a battery containing M-CSE.

[0036] Figure 4-11 This is a microscopic image of the composite solid electrolyte (M-CSE) in the present invention, where Figure 4 This is a SEM cross-sectional image with a resolution of 200 μm. Figure 5 The SEM cross-sectional view and EDX image with a resolution of 10 μm are shown. Figure 6 The SEM cross-sectional view and EDX image with a resolution of 2 μm are shown. Figure 7 The SEM cross-sectional view and EDX image with a resolution of 7 μm are shown. Figure 8 This is a cross-sectional SEM image of the lithium metal and electrolyte contact side of the battery in Comparative Example 2 after 40 hours of rest. Figure 9 This is a cross-sectional SEM image of the lithium metal and electrolyte contact side of the battery in Comparative Example 1 after 40 hours of rest. Figure 10 This is a cross-sectional SEM image (resolution 30 μm) of the contact side between lithium metal and M-CSE in the battery of Example 1 after 40 hours of rest. Figure 11 This is a cross-sectional SEM image (resolution 15 μm) of the contact side between the lithium metal and the M-CSE of the battery in Example 1 after 40 hours of rest.

[0037] Figure 12-17 The critical current density (CCD) test results of the battery under different electrolyte configurations are shown in Figure 2. Figure 12This is the critical current density (CCD) test curve of the battery in comparative example 1. Figure 13 This is the critical current density (CCD) test curve of the battery in comparative example 2. Figure 14 This is a critical current density (CCD) test curve of the battery in Example 3. Figure 15 This is a critical current density (CCD) test curve of the battery in Example 2. Figure 16 This is a critical current density (CCD) test curve of the battery in Example 1. Figure 17 Graphs showing cycle stability tests of the batteries in Example 1, Example 2, and Example 3.

[0038] Figures 18-24 The rate performance and corresponding charge-discharge curve test results of the battery under different electrolyte configurations are shown in Figure 2. Figure 18 、 Figure 19 、 Figure 20 is the rate performance test result, Figure 21 、 Figure 22 、 Figure 23 、 Figure 24 The charge and discharge curve test results.

[0039] Figures 25-30 The discharge capacity and coulombic efficiency of the battery under different electrolyte configurations and the corresponding charge and discharge curve test results are shown in Figure 2. Figure 25 、 Figure 26 、 Figure 27 The discharge capacity and coulombic efficiency test results of the battery at 0.5C rate are as follows: Figure 28 、 Figure 29 、 Figure 30 The charge and discharge curve test results of the battery corresponding to different cycle numbers.

[0040] Figure 31-Figure 35 is the XPS spectrum of the composite solid electrolyte (M-CSE), where Figure 31 is the CI2p region collected from the electrolyte interior and the M-CSE / Li interface, Figure 32 is the Sn3d region collected from the electrolyte interior and the M-CSE / Li interface, Figure 33 is the S2p region collected from the electrolyte interior and the M-CSE / Li interface, Figure 34 、 Figure 35 XRD patterns and Raman spectra of M-CSE, LPSCI and LSiSnPSBrO, respectively.

[0041] Figures 36-41 The test results of solid-state battery charge and discharge performance under different surface capacities are shown below. Figure 36 The charge and discharge curves of LCO|LPSCl-M-CSE|Li batteries with different surface capacities are shown in Figure 2. Figure 37The charge and discharge curves of the LCO|LPSCl-M-CSE|Li square prismatic soft pack battery with a side length of 2 cm Figure 38 、 Figure 39 、 Figure 40 The surface capacity is 5 mAh cm −2 The charge-discharge curves, rate capability and cycle performance of the LCO|LPSCl-M-CSE|Li battery. Figure 41 Nyquist plots of LCO|LPSCl-M-CSE|Li battery after different cycle times.

[0042] Figure 42 Schematic diagram of the stacking pressure test of the all-solid-state battery in the present invention. DETAILED DESCRIPTION

[0043] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0044] Unless otherwise specified, the raw materials used in the examples of the present invention are all commercially available or available to those skilled in the art; unless otherwise specified, the methods used in the examples of the present invention are all methods known to those skilled in the art.

[0045] A composite solid electrolyte (M-CSE) includes the following components: LPSCl, LSiSnPSBrO, the mass fraction of LSiSnPSBrO is 10wt%-30wt%; the LPSCl is Li 5.3 PS 4.3 Cl 1.7 , the LSiSnPSBrO is Li 9.54 [Si 0.5 Sn 0.5 ]PSBrO.

[0046] The composite solid electrolyte is prepared as follows: LPSCl and LSiSnPSBrO powders are manually ground in an agate mortar for 10 minutes or ball-milled in a planetary ball mill for 10 minutes according to the required mass ratio to obtain the composite solid electrolyte (M-CSE), which is referred to as M-CSE layer in the following examples. Unless otherwise specified, M-CSE refers to a layer containing 10 wt% Li 9.54 [Si 0.5 Sn 0.5 ]PSBrO composite electrolyte.

[0047] The LCO positive electrode is a composite positive electrode, and the preparation method of the composite positive electrode is as follows: the positive electrode material is obtained by ball milling LCO, VGCF and LPSCl in a mass ratio of 60:5:35 at a rotation speed of 100 rpm for 0.2 h; the LPSCl is Li6PS5Cl, and the preparation method of Li6PS5Cl is as follows: Li2S, P2S5 and LiCl are mixed in a molar ratio of 5:1:2, set the rotation speed to 600 rpm, and ball mill for 12 h; sintering at 550°C for 12 h under an argon atmosphere at a heating rate of 5°C / min, and finally crushing to obtain Li6PS5Cl.

[0048] Example 1: A method for preparing an all-solid-state battery, the method comprising the following steps: (1) pressing 60 mg of LiPSCl into a 10 mm diameter disc at a pressure of 124 MPa to form a SE layer; the LPSCl is Li 5.3 PS 4.3 Cl 1.7 .

[0049] (2) 20 mg of M-CSE composite electrolyte was placed on each side of the SE layer and pressed at a pressure of 496 MPa for 2 minutes to make the three layers fit tightly together; the mass fraction of LSiSnPSBrO in the M-CSE composite electrolyte was 10 wt%.

[0050] (3) Place a Li sheet with a diameter of 10 mm and a thickness of 20 μm on each side of the above (2) layer and press it at a pressure of 30 MPa for 2 minutes to make the two fit tightly together, completing the symmetrical battery assembly and obtaining the "Li|M-CSE-LPSCl-M-CSE|Li" battery.

[0051] Example 2: A method for preparing an all-solid-state battery, the method comprising the following steps: (1) pressing 60 mg of LiPSCl into a 10 mm diameter disc at a pressure of 124 MPa to form a SE layer; the LPSCl is Li 5.3 PS 4.3 Cl 1.7 .

[0052] (2) 20 mg of M-CSE composite electrolyte was placed on each side of the SE layer and pressed at a pressure of 496 MPa for 2 minutes to make the three closely fit together; the mass fraction of LSiSnPSBrO in the M-CSE composite electrolyte was 20 wt%.

[0053] (3) Place a Li sheet with a diameter of 10 mm and a thickness of 20 μm on each side of the above (2) layer and press it at a pressure of 30 MPa for 2 minutes to make the two fit tightly together, completing the symmetrical battery assembly and obtaining the "Li|M-CSE-LPSCl-M-CSE|Li" battery.

[0054] Example 3: A method for preparing an all-solid-state battery, the method comprising the following steps: (1) pressing 60 mg of LiPSCl into a 10 mm diameter disc at a pressure of 124 MPa to form a SE layer; the LPSCl is Li 5.3 PS 4.3 Cl 1.7 .

[0055] (2) 20 mg of M-CSE composite electrolyte was placed on each side of the SE layer and pressed at a pressure of 496 MPa for 2 minutes to make the three layers fit tightly together; the mass fraction of LSiSnPSBrO in the M-CSE composite electrolyte was 30 wt%.

[0056] (3) Place a Li sheet with a diameter of 10 mm and a thickness of 20 μm on each side of the above (2) layer and press it at a pressure of 30 MPa for 2 minutes to make the two fit tightly together, completing the symmetrical battery assembly and obtaining the "Li|M-CSE-LPSCl-M-CSE|Li" battery.

[0057] Example 4: A method for preparing an all-solid-state battery, the method comprising the following steps: (1) adding 60 mg of Li 5.3 PS 4.3 Cl 1.7 The SE layer was formed by pressing the pellets into discs with a diameter of 10 mm under a pressure of 124 MPa.

[0058] (2) Place 10 mg of LCO positive electrode on one side of the SE layer and press it at a pressure of 496 MPa for 2 minutes to make the two fit tightly together.

[0059] (3) 20 mg of pre-synthesized M-CSE was placed on the other side of the SE layer and pressed at a pressure of 868 MPa for 2 min to form an M-CSE layer. The M-CSE layer was tightly bonded to the SE layer. The mass fraction of LSiSnPSBrO in the M-CSE composite electrolyte was 10 wt%.

[0060] (4) A 10 mm lithium sheet is placed on the other side of the M-CSE layer. The lithium sheet is a lithium metal negative electrode. The all-solid-state battery is assembled to obtain "LCO / Li 5.3 PS 4.3 Cl 1.7 -M-CSE / Li” battery.

[0061] Example 5: A method for preparing an all-solid-state battery, the method comprising the following steps: (1) adding 60 mg of Li 5.5 PS 4.5 Cl 1.5The SE layer was formed by pressing the pellets into discs with a diameter of 10 mm under a pressure of 124 MPa.

[0062] (2) Place 10 mg of LCO positive electrode on one side of the SE layer and press it at a pressure of 496 MPa for 2 minutes to make the two fit tightly together.

[0063] (3) 20 mg of pre-synthesized M-CSE was placed on the other side of the SE layer and pressed at a pressure of 868 MPa for 2 min to form an M-CSE layer. The M-CSE layer was tightly bonded to the SE layer. The mass fraction of LSiSnPSBrO in the M-CSE composite electrolyte was 10 wt%.

[0064] (4) A 10 mm lithium sheet is placed on the other side of the M-CSE layer. The lithium sheet is a lithium metal negative electrode. The all-solid-state battery is assembled to obtain "LCO / Li 5.5 PS 4.5 Cl 1.5 -M-CSE / Li” battery.

[0065] Example 6: A method for preparing an all-solid-state battery, the method comprising the following steps: (1) pressing 60 mg of Li6PS5Cl into a disc with a diameter of 10 mm at a pressure of 124 MPa to form an SE layer.

[0066] (2) Place 10 mg of LCO positive electrode on one side of the SE layer and press it at a pressure of 496 MPa for 2 minutes to make the two fit tightly together.

[0067] (3) 20 mg of pre-synthesized M-CSE was placed on the other side of the SE layer and pressed at a pressure of 868 MPa for 2 min to form an M-CSE layer. The M-CSE layer was tightly bonded to the SE layer. The mass fraction of LSiSnPSBrO in the M-CSE composite electrolyte was 10 wt%.

[0068] (4) A 10 mm lithium sheet is placed on the other side of the M-CSE layer. The lithium sheet serves as a lithium metal negative electrode. The all-solid-state battery is assembled to obtain an "LCO / Li6PS5Cl-M-CSE / Li" battery.

[0069] Example 7: A preparation method for a 3D printed soft-pack battery, the preparation method comprising the following steps: Step S1, taking a certain amount of composite positive electrode, negative electrode, electrolyte and M-CSE material; then adding 8% by mass of nitrile rubber (NBR) to the composite positive electrode, electrolyte and M-CSE respectively to prepare positive electrode printing slurry, electrolyte printing slurry and M-CSE printing slurry.

[0070] Step S2: Place the positive electrode printing slurry, electrolyte printing slurry and M-CSE printing slurry in multiple nozzles of the 3D printer respectively, and print M-CSE, electrolyte and composite positive electrode on the negative electrode in sequence by switching the nozzles.

[0071] Step S3: Add aluminum-plastic film to the printed battery structure to complete the packaging.

[0072] Step S4: isostatically compacting at 2 MP to obtain a solid-state battery.

[0073] The preparation method of the composite positive electrode is as follows: the positive electrode material is obtained by ball milling LCO, VGCF and LPSCl with a mass ratio of 60:5:35 at a rotation speed of 100 rpm for 0.2 h.

[0074] The negative electrode is a copper-lithium composite strip, wherein the thickness of the lithium strip is 20 μm and the thickness of the copper strip is 20 μm.

[0075] The electrolyte is Li 5.3 PS 4.3 Cl 1.7 .

[0076] The M-CSE material is the composite solid electrolyte.

[0077] Comparative Example 1: A method for preparing an all-solid-state battery, the method comprising the following steps: (1) pressing 60 mg of LSiSnPSBrO into a 10 mm diameter disc at a pressure of 124 MPa to form a SE layer; the LSiSnPSBrO is Li 9.54 [Si 0.5 Sn 0.5 ]PSBrO.

[0078] (2) Li sheets with a diameter of 10 mm and a thickness of 20 μm were placed on both sides of the SE layer and pressed at a pressure of 30 MPa for 2 minutes to make the two fit tightly together, completing the symmetrical battery assembly and obtaining a "Li / LSiSnPSBrO / Li" battery.

[0079] Comparative Example 2: A method for preparing an all-solid-state battery, the method comprising the following steps: (1) adding 60 mg of Li 5.3 PS 4.3 Cl 1.7 The SE layer was formed by pressing the pellets into discs with a diameter of 10 mm under a pressure of 124 MPa.

[0080] (2) Place a Li sheet with a diameter of 10 mm and a thickness of 20 μm on each side of the SE layer, press it under a pressure of 30 MPa for 2 minutes to make the two fit tightly together, and complete the symmetrical battery assembly to obtain "Li / Li 5.3 PS4.3 Cl 1.7 / Li” battery.

[0081] Through the description of the above examples 1 to 7 and comparative examples 1 to 2, the following conclusions are drawn: The prior art discloses that in sulfide-based solid-state batteries, due to the thermodynamic instability between the sulfide electrolyte and lithium metal, a decomposition reaction may occur when they come into contact, producing unwanted byproducts, which are generally referred to as mixed conductive interface (MCI) ( Figure 1 ). The above-mentioned mixed conductive interface (MCI) affects the transmission of lithium ions and the stability of the interface to a certain extent. The use of sulfide solid electrolytes alone will cause the electrolyte to continue to decompose at the interface, resulting in an unstable MCI layer. The MCI layer tends to thicken over time and become an ion insulating layer, which hinders the effective transmission of lithium ions. In addition, when the electrolyte comes into contact with the lithium metal negative electrode, an irreversible reaction occurs to form a solid electrolyte interface (SEI) ( Figure 2 The uneven deposition of the SEI layer on the lithium metal surface results in a nonuniform current density distribution. In areas of higher current density, lithium ions deposit more rapidly, making dendrite formation more likely. This is because the rapid deposition of lithium metal in these localized areas leads to the formation of tips or protrusions, which can evolve into lithium dendrites. Due to the brittle nature of the SEI material, it is prone to cracking during the expansion and contraction of the lithium metal.

[0082] When the SEI layer breaks, the exposed lithium metal directly contacts the electrolyte, forming a new SEI layer. At the same time, the deposition of lithium metal becomes uncontrollable, resulting in an irregular deposition structure, which further promotes the growth of lithium dendrites. In contrast, when M-CSE ( Figure 3 ), it can effectively improve the stability and reliability of battery performance, especially under conditions of high current density and long cycle life. The M-CSE layer inherits its advantages of high chemical stability and good interfacial affinity. This not only protects the electrode material from corrosive side reactions but also provides a smooth path for lithium ion conduction. In addition, local interfacial passivation occurs, which reduces the stress caused by volume change and maintains the compactness and stability of the interface.

[0083] The interfacial passivation effect further inhibits electrolyte decomposition, effectively slowing the growth of lithium dendrites. Furthermore, the lithium-ion conductive material (such as Li-Sn alloy) in the M-CSE layer facilitates uniform lithium deposition and ensures a uniform electric field distribution, thereby guiding the stable nucleation and growth of lithium. Therefore, through the dual regulatory mechanisms of physical isolation and chemical equilibrium, the M-CSE layer can effectively inhibit the growth of lithium dendrites and prevent them from penetrating the solid electrolyte.

[0084] The introduction of the M-CSE layer into the battery significantly improves its critical current density (CCD), enabling it to exhibit excellent electrochemical stability even at high current densities. Through the combined effects of physical barrier properties and chemical stability, the M-CSE layer provides substantial protection for the battery, thereby improving its overall performance and extending its service life.

[0085] In order to verify and accurately illustrate the concept of the present invention, the present invention prepares a composite electrolyte by finely mixing two types of electrolytes. Through a series of design and screening processes, the present invention selects Li 5.3 PS 4.3 Cl 1.7 He Li 9.54 [Si 0.5 Sn 0.5 ]PSBrO, these two electrolytes were studied in depth.

[0086] In order to demonstrate the uniformity of the composite electrolyte layer, the composite electrolyte of the present invention was cold pressed at 250 MPa, and the low magnification cross-sectional SEM image ( Figure 4 , resolution 200 μm), the composite electrolyte layer shows densely packed particles with no visible cracks. At higher magnification ( Figure 5 , resolution 10um; Figure 6 , resolution 2um; Figure 7 , 7 μm resolution), two distinct morphological regions can be clearly observed. The finely mixed electrolyte shows one region with large particles, approximately tens of microns in size, and another region with small particles aggregated into clusters, typically a few microns in size. These two types of electrolytes are tightly compressed together. In addition, energy dispersive X-ray spectroscopy (EDX) analysis ( Figure 5 ) confirmed that the large particle area contains a lot of Cl, while the small particle area is rich in Sn, further indicating that the former is Li 9.54 [Si 0.5 Sn 0.5 ]PSBrO, the latter is Li 5.3 PS 4.3 Cl 1.7 ; Figure 5 The purple part is the electrolyte Li 5.3 PS 4.3 Cl 1.7 , the blue part is the electrolyte Li 9.54 [Si 0.5 Sn 0.5 ]PSBrO.

[0087] In addition, in order to study the stability of different electrolytes and lithium metal, the present invention uses three different sulfide electrolytes to make a symmetrical battery. After standing for 40 hours, the lithium metal and electrolyte contact side cross-sectional SEM images are as follows: Li / Li 5.3 PS 4.3 Cl 1.7 / Li (Comparative Example 1), Li / Li 9.54 [Si 0.5 Sn 0.5 ]PSBrO / Li (Comparative Example 2), Li|M-CSE-LPSCl-M-CSE|Li (Example 1) are three symmetrical lithium batteries with different electrolyte structures. 9.54 [Si 0.5 Sn 0.5 ]PSBrO electrolyte, a continuous interfacial degradation reaction occurs with lithium metal, resulting in continuous decomposition of the electrolyte and the formation of a degraded MCI layer ( Figure 8 , Li / Li 9.54 [Si 0.5 Sn 0.5 ]PSBrO / Li (Comparative Example 2) symmetrical battery after 40 hours of rest (SEM image of the contact side between lithium metal and electrolyte). 5.3 PS 4.3 Cl 1.7 In the case of the electrolyte (a conventional silver-like sulfide electrolyte), uneven growth of lithium dendrites was observed at the interface due to the presence of a non-uniform interfacial reaction layer and electrochemical polarization, leading to further expansion of the dendrites ( Figure 9 , Li / Li 5.3 PS 4.3 Cl 1.7 / Li (Comparative Example 1) symmetrical battery after 40 hours of rest (SEM image of the lithium metal and electrolyte contact side). In contrast, M-CSE exhibits excellent interfacial stability during lithium deposition ( Figure 10 、 Figure 11 , cross-sectional SEM images of the lithium metal-M-CSE contact side of the symmetric cell Li|M-CSE-LPSCl-M-CSE|Li (Example 1) at different magnifications after 40 hours of rest), which can be attributed to its unique in-situ lithophilic interface properties, providing a uniform lithium deposition pathway and suppressing stress at the interface through passivation.

[0088] Furthermore, in order to verify the effect of electrolyte on the critical current density (CCD) of the battery, the present invention adopts Li / Li 5.3 PS 4.3 Cl 1.7 / Li (Comparative Example 1), Li / Li 9.54 [Si 0.5 Sn 0.5]PSBrO / Li (Comparative Example 2) and Li|M-CSE-LPSCl-M-CSE|Li (Example 1) are used to study the differences in their critical current density (CCD) of symmetrical lithium batteries with different electrolyte structures.

[0089] Specifically, the critical current density refers to the maximum current density that the lithium metal electrode can carry in this battery structure. When this value is exceeded, the lithium metal may nucleate and grow dendrites, resulting in a decrease in battery performance or even a short circuit.

[0090] The cycling stability of solid-state lithium metal symmetric batteries at a specific current density is a crucial performance indicator, directly related to the safety, reliability, and longevity of the battery. In particular, in solid-state batteries, the deposition and desorption behavior of the lithium metal electrode, interfacial stability, and current density management all determine the cycling stability of the battery.

[0091] Figure 12-17 Shows the CCD test results. Li / Li 5.3 PS 4.3 Cl 1.7 The symmetrical cell in the / Li (Comparative Example 1) was 2.16 mA cm -2 The CCD is short-circuited ( Figure 12 ), indicating that the refined single electrolyte Li 5.3 PS 4.3 Cl 1.7 In contrast, Li / Li 9.54 [Si 0.5 Sn 0.5 The symmetrical cell in PSBrO / Li (Comparative Example 2) was 0.66 mA cm -2 Short circuit at lower current density ( Figure 13 ), indicating that its stability with lithium metal needs to be further improved.

[0092] Notably, the optimized hybrid M-CSE (Li|M-CSE-LPSCl-M-CSE|Li (Example 1)) achieved an impressive 3.76 mA cm in a symmetric Li metal cell. -2 CCD ( Figure 16 ), which is significantly enhanced compared with a single electrolyte.

[0093] In addition, the performance of M-CSE under different compositions was studied. The current density of the present invention was 1.3 mA cm -2 Li / Li 5.3 PS 4.3 Cl 1.7 / Li (Comparative Example 1).

[0094] Li / M-CSEwith10,wt%Li 9.54 [Si 0.5 Sn 0.5 ]PSBrO-Li 5.3 PS 4.3 Cl 1.7 -M-CSEwith10,wt%Li 9.54 [Si 0.5 Sn 0.5 ]PSBrO / Li (Example 1).

[0095] Li / M-CSEwith20,wt%Li 9.54 [Si 0.5 Sn 0.5 ]PSBrO-Li 5.3 PS 4.3 Cl 1.7 -M-CSEwith20,wt%Li 9.54 [Si 0.5 Sn 0.5 ]PSBrO / Li (Example 2).

[0096] Li / M-CSEwith30,wt%Li 9.54 [Si 0.5 Sn 0.5 ]PSBrO-Li 5.3 PS 4.3 Cl 1.7 -M-CSEwith30,wt%Li 9.54 [Si 0.5 Sn 0.5 ]PSBrO / Li (Example 3).

[0097] Cycling stability analysis of four symmetrical batteries.

[0098] As shown in the figure, increasing Li 9.54 [Si 0.5 Sn 0.5 ]PSBrO electrolyte content leads to a decrease in CCD ( Figure 14 、 Figure 15 、 Figure 17 ). Therefore, the optimal composition was determined to contain 10wt%Li 9.54 [Si 0.5 Sn 0.5 ]M-CSE of PSBrO. The higher CCD value indicates that the growth of lithium dendrites is effectively suppressed, confirming the effectiveness of the electrolyte design. Figure 17 Further comparison was made at 1.5 mA cm -2 At a current density of 1.5 Å, a single electrolyte Li 5.3PS 4.3 Cl 1.7 (Comparative Example 1) and M-CSE battery long-term cycling stability. Single electrolyte Li 5.3 PS 4.3 Cl 1.7 (Comparative Example 1) short circuit occurred after 20 hours, while 10wt%Li 9.54 [Si 0.5 Sn 0.5 ]PSBrO M-CSE (Example 1) maintains stable cycling after 650 hours of plating / stripping. In contrast, Li 9.54 [Si 0.5 Sn 0.5 ] The M-CSE with 20wt% (Example 2) and 30wt% (Example 3) PSBrO short-circuited after 130h and 475h. These results further emphasize that 10wt% Li 9.54 [Si 0.5 Sn 0.5 ]PSBrO M-CSE has excellent plating / stripping performance and dendrite suppression ability.

[0099] Furthermore, to verify the broad applicability of M-CSE, all-solid-state batteries (ASSLMBs) were fabricated using lithium metal anodes, various sulfide electrolytes, M-CSE, and LCO cathodes. The rate performance of a battery reflects its power output and charging efficiency, making it a key step in the development and evaluation of battery technology. Figures 18-24 It shows that when the current rate is changed from 0.1C (0.05mAcm -2 ) is gradually increased to 0.2C, 0.5C, 1C, 2C and 5C. All batteries were tested between 2.5V and 4.2V.

[0100] like Figure 18 As shown, LCO|Li6PS5Cl|Li, LCO|Li 5.5 PS 4.5 Cl 1.5 |Li、LCO|Li 5.3 PS 4.3 ClBr 0.7 |Li、LCO|Li 5.3 PS 4.3 Cl 1.7 |Li four-group battery experiment comparison, in the all-solid-state battery (ASSLMB) without M-CSE, only LCO|Li 5.3 PS 4.3 ClBr 0.7| The Li configuration has no short circuit at 5C, but its reversible specific capacity at 5C is only 86.7 mAh g -1 , which deviates greatly from the theoretical specific capacity of the LCO cathode. For other all-solid-state batteries (ASSLMBs) without M-CSE, their rate performance is even worse, with short circuits occurring between 0.2C and 1C, indicating poor rate capability.

[0101] like Figure 19 As shown, LCO|Li6PS5Cl-M-CSE|Li (Example 6), LCO|Li 5.5 PS 4.5 Cl 1.5 -M-CSE|Li (Example 5), LCO|Li 5.3 PS 4.3 ClBr 0.7 -M-CSE|Li、LCO|Li 5.3 PS 4.3 Cl 1.7 -M-CSE|Li (Example 4) Four groups of battery configurations were compared experimentally. After adding M-CSE to the electrolyte, the rate performance of the battery showed significant improvement. For the best performing configuration LCO|Li 5.5 PS 4.5 Cl 1.5 -M-CSE|Li, the battery exhibits very low polarization and achieves 163.7 mAh g at a low rate of 0.1C -1 As the rate increases to 0.2C, 0.5C, 1C, 2C and 5C, the reversible specific capacity gradually decreases to 162.9, 159.5, 155.7, 150 and 138.7 mAh g -1 . This demonstrates the excellent reversible capacity and capacity retention at high rates. In addition, after 5 charge-discharge cycles at 5C, the reversible capacity at 2C was almost completely restored to its original level when the battery was tested again at a lower rate. This phenomenon indicates that the all-solid-state battery (ASSLMB) with M-CSE exhibits excellent reversibility and excellent performance under high-rate conditions. In addition, it also shows that the in-situ protective layer formed by M-CSE suppresses the growth of lithium dendrites, enabling the all-solid-state battery (ASSLMB) to withstand high current conditions.

[0102] like Figure 20 As shown in the figure, the rate performance of all-solid-state batteries (ASSLMBs) with different M-CSE ratios was studied, especially M-CSE (10%, 20%, 30%Li 9.54 [Si 0.5 Sn 0.5 ]PSBrO).

[0103] Figure 20 The battery structure adopts LCO / Li 5.3 PS 4.3 Cl 1.7 -M-CSE / Li. Since M-CSE is composed of two electrolytes Li 5.3 PS 4.3 Cl 1.7 He Li 9.54 [Si 0.5 Sn 0.5 ]PSBrO is mixed in a certain proportion. Figure 20 In order to explore the ratio of the two electrolytes, the M-CSE has better performance. 9.54 [Si 0.5 Sn 0.5 ]PSBrO means that the mass ratio of Li in M-CSE is 5.3 PS 4.3 Cl 1.7 :Li 9.54 [Si 0.5 Sn 0.5 ]PSBrO=9:1. Similarly, 20%%Li 9.54 [Si 0.5 Sn 0.5 ]PSBrO is 8:2, 30%%Li 9.54 [Si 0.5 Sn 0.5 ]PSBrO is 7:3, 0%%Li 9.54 [Si 0.5 Sn 0.5 ]PSBrO is 10:0. Figure 20 When M-CSE is mentioned elsewhere, it is assumed that M-CSE stands for Li 5.3 PS 4.3 Cl 1.7 :Li 9.54 [Si 0.5 Sn 0.5 ]PSBrO=9:1.

[0104] Meanwhile, further explanation is as follows: the electrolyte of the present invention, wherein Li 5.3 PS 4.3 ClBr 0.7 It is doped with Br element. The electrolyte Li 5.3 PS 4.3 Cl 1.7 and Li6PS5Cl and Li 5.5 PS 4.5 Cl 1.5 These three electrolytes are not doped with Br, and their essential difference lies in the different Cl element contents.

[0105] The results show that as Li 9.54 [Si 0.5 Sn 0.5 ]With the increase of PSBrO content, the discharge capacity at 5C gradually decreased to 133.4, 86.7 and 80.1 mAh g -1 This decrease is attributed to the 9.54 [Si 0.5 Sn 0.5 ]With the increase of PSBrO content, the dynamic stability of the interfacial layer formed by interfacial passivation is destroyed, resulting in greater polarization due to side reactions between lithium metal and solid electrolyte (SE).

[0106] like Figure 21 、 Figure 22 、 Figure 23 、 Figure 24 As shown, using: LCO|Li6PS5Cl-M-CSE|Li, LCO|Li 5.5 PS 4.5 Cl 1.5 -M-CSE|Li、LCO|Li 5.3 PS 4.3 ClBr 0.7 -M-CSE|Li、LCO|Li 5.3 PS 4.3 Cl 1.7 -M-CSE|Li four-group configuration battery experimental comparison, charge and discharge curves after adding M-CSE.

[0107] Furthermore, in order to verify the wide applicability of M-CSE, Figures 25-30 The long-cycle performance and corresponding Coulombic efficiency of all-solid-state batteries (ASSLMBs) fabricated from lithium metal anode, various sulfide electrolytes, M-CSE, and LCO cathode are shown.

[0108] like Figure 25 , using LCO|Li 5.5 PS 4.5 ClBr 1.5 |Li、LCO|Li 5.5 PS 4.5 ClBr 1.5 -M-CSE|Li was used to compare the cycle life performance and capacity attenuation performance of the battery without M-CSE and with M-CSE. Specifically, at a rate of 0.5C (surface capacity of 0.98 mAh cm -2 ) discharge capacity and Coulombic efficiency.

[0109] like Figure 26 , using LCO|Li 5.3 PS4.3 Cl 1.7 |Li、LCO|Li 5.3 PS 4.3 Cl 1.7 -M-CSE|Li was used to compare the cycle life performance and capacity attenuation performance of the battery without M-CSE and with M-CSE. Specifically, at a rate of 0.5C (surface capacity of 0.98 mAh cm -2 ) discharge capacity and Coulombic efficiency.

[0110] As shown in 27, LCO|Li6PS5Cl|Li and LCO|Li6PS5Cl-M-CSE|Li were used to compare the cycle life performance and capacity decay performance of batteries without and with M-CSE. Specifically, at a rate of 0.5C (surface capacity of 0.98 mAh cm -2 ) discharge capacity and Coulombic efficiency.

[0111] For example, 28, LCO|Li 5.5 PS 4.5 ClBr 1.5 |Li、LCO|Li 5.5 PS 4.5 ClBr 1.5 -M-CSE|Li compares the cycle life performance and capacity decay performance of batteries without and with M-CSE, specifically the charge and discharge curves corresponding to different cycle numbers.

[0112] As shown in 29, LCO|Li 5.3 PS 4.3 Cl 1.7 |Li、LCO|Li 5.3 PS 4.3 Cl 1.7 -M-CSE|Li compares the cycle life performance and capacity decay performance of batteries without and with M-CSE, specifically the charge and discharge curves corresponding to different cycle numbers.

[0113] As shown in Figure 30, LCO|Li6PS5Cl|Li and LCO|Li6PS5Cl-M-CSE|Li were used to compare the cycle life performance and capacity decay performance of batteries without and with M-CSE added, specifically the charge and discharge curves corresponding to different cycle numbers.

[0114] The results show that the battery with the addition of M-CSE exhibits a longer cycle life and lower capacity decay during cycling at 0.5C. As shown in 25, LCO|Li 5.5 PS 4.5 ClBr 1.5-M-CSE|Li full battery at 0.5C (1mAcm -2 ) After 250 cycles, it still maintains 134.5mAhg -1 The discharge specific capacity, capacity retention rate and Coulomb efficiency are 90.1% and 99.91%.

[0115] Likewise, Figure 26 As shown, LCO / Li 5.3 PS 4.3 Cl 1.7 -M-CSE / Li battery still maintains 133.3mAhg after 300 cycles at 0.5C -1 The discharge specific capacity, capacity retention rate and Coulomb efficiency are 90.2% and 99.92%.

[0116] Even more impressive is that Figure 27 As shown in Figure 2, the LCO / Li6PS5Cl-M-CSE / Li battery exhibits better performance, maintaining 124.3 mAh g after 500 cycles. −1 The discharge capacity of the battery was 1.333W, with a capacity retention rate of 95.04%, representing a major breakthrough in electrochemical performance.

[0117] In comparison, the battery without M-CSE exhibited lower reversible capacity and poor cycling performance, while the battery with M-CSE exhibited higher reversible capacity and better cycling performance.

[0118] Specifically, the discharge capacities of the LCO / Li6PS5Cl-M-CSE / Li battery at the 100th, 200th, 300th, and 500th cycles were 126.6, 125.8, 125.3, and 124.3 mAh g -1 (like Figure 30 ).

[0119] LCO|Li 5.3 PS 4.3 Cl 1.7 The M-CSE|Li battery exhibited 141.1 and 133.3 mAh g at the 150th and 300th cycles, respectively. -1 The discharge capacity (such as Figure 29 ).

[0120] LCO|Li 5.5 PS 4.5 ClBr 1.5 The discharge capacities of the M-CSE|Li battery at the 150th and 250th cycles were 136.1 and 134.5 mAh g, respectively. -1 (like Figure 28 ).

[0121] At the same time, in order to verify the state of the composite solid electrolyte (M-CSE) after mixing, XPS spectrum of the M-CSE electrolyte was collected.

[0122] For the spectrum collected at the M-CSE / Li interface, an additional peak was observed at 54.8 eV, which was attributed to Li0. This peak comes from the interfacial reaction products, especially the Li-Sn / Si alloy, and lithium adhering to the surface. Figure 31 As shown in Figure 2, the S2p spectrum collected from inside the M-CSE electrolyte does not change significantly before and after cycling, showing two peaks at 162.6eV and 161.4eV, attributed to SnS43- and PS43-. In contrast, after cycling, the spectrum collected at the M-CSE / Li interface exhibits two peaks corresponding to Li2S (161.3eV and 160.2eV), indicating that the M-CSE electrolyte is significantly lithiated. This suggests that in the M-CSE electrolyte, decomposition mainly occurs at the interface and is well suppressed within the electrolyte. Similar conclusions can be drawn from the P2p spectrum (e.g., Figure 32 The initial spectrum shows P2p peaks at 132.6 eV and 131.8 eV, attributed to SnS43- and PS43-. After cycling, the spectrum collected from the interior shows almost the same signals, while the spectrum collected at the interface shows additional peaks at 128.6 eV and 127.9 eV, corresponding to the electrolyte decomposition product Li3P. The Sn3d spectrum (as shown) Figure 33 As shown, ) shows that Li 9.54 [Si 0.5 Sn 0.5 ]Sn4+ exists in PSBrO. However, after cycling, the peak intensity in the Sn3d spectrum collected at the interface decreases significantly. In addition, new peaks appear at 491.7eV and 483.5eV, corresponding to Li-Sn alloys, indicating that Li 9.54 [Si 0.5 Sn 0.5 ]PSBrO occurs at the M-CSE / Li interface. Fine XPS scans of Cl collected from the interior and interface showed no significant changes after cycling, confirming that Li 5.3 PS 4.3 Cl 1.7 According to the XPS results, it can be concluded that after rate cycling, Li 9.54 [Si 0.5 Sn 0.5 ]The decomposition of PSBrO is mainly confined to the M-CSE / Li interface. 9.54 [Si 0.5 Sn 0.5This limited decomposition of PSBrO serves to consume the lithium dendrites formed under high current while preventing the continued growth of a highly resistive interfacial layer.

[0123] XRD refinement further confirmed that the primary structure of the synthesized LiSiSnPSBrO is Li 9.54 [Si 0.5 Sn 0.5 ]PSBrO. In addition, the sample contains 7.13wt% of Li2SnS3 phase. Figure 34 As shown, the pre-synthesized Li 5.3 PS 4.3 Cl 1.7 He Li 9.54 [Si 0.5 Sn 0.5 The superposition of ]PSBrO can well reproduce the XRD patterns of M-CSE, indicating that the two solid electrolytes are physically mixed in M-CSE.

[0124] like Figure 35 As shown, 200-550cm -1 Raman spectra of electrolyte powder in the wavenumber range. 9.54 [Si 0.5 Sn 0.5 ] The results of other reports on PSBrO are consistent, 422 cm -1 and 416cm -1 The strongest Raman peak at 346 cm is attributed to PS4 tetrahedron, while -1 The peak at 308 cm is attributed to SnS4 tetrahedron. -1 The peak at 422 cm corresponds to the SnS3 unit and is attributed to the impurity Li2SnS3. -1 The Raman spectrum of M-CSE is the same as that of pre-synthesized Li 5.3 PS 4.3 Cl 1.7 He Li 9.54 [Si 0.5 Sn 0.5 The superposition of the PSBrO spectra further supports the conclusion that the two solid electrolytes are physically mixed without any chemical reaction.

[0125] Overall, the all-solid-state battery (ASSLMB) using M-CSE exhibits excellent electrochemical performance, providing strong feasibility support for the development of high specific surface area and high-type batteries in the future.

[0126] After adding M-CSE, the all-solid-state battery (ASSLMB) not only exhibits excellent rate and long cycle performance, but also achieves extremely high areal capacity, such as Figure 36 As shown, LCO / Li 5.3 PS 4.3 Cl 1.7 -M-CSE / Li battery at 2, 5 and 10 mAh cm -2 It operates stably at ultra-high surface capacity. -2 When the battery shows 125.9mAhg -1 The reversible specific capacity is quite remarkable considering the high areal capacity. -2 The battery also exhibits excellent rate performance, maintaining approximately 100 mAh g at 2C. -1 The reversible specific capacity (such as Figure 38 、 Figure 39 ). In addition, at 5mAhcm -2 Surface capacity and 1mAcm -2 After 50 cycles at a high current density, the reversible specific capacity retention rate was 90.8% (e.g. Figure 40 、 Figure 41 ).

[0127] In view of the excellent performance of all-solid-state batteries (ASSLMBs) under M-CSE and to demonstrate the practical application potential of this structure, the present invention uses a 3D printing method to assemble a square battery with a side length of 2 cm (Example 7). The active material content of the cathode is 70%, and the surface loading is 20 mg cm -2 In the first discharge cycle, the battery achieved 128.92 mAh g -1 The specific capacity is up to 170Whkg -1 Energy density (energy density is calculated based on the total mass of battery materials, including cathode, electrolyte and anode) (such as Figure 37 The automated nature of 3D printing also offers a path to large-scale production of sulfide-based all-solid-state batteries. Under the ultra-low natural stacking pressure of 3D printing, the battery exhibits reduced expansion potential, maintains stable shape and function, and minimizes mechanical stress and fatigue within the internal materials.

[0128] like Figure 42 Shown in the figure is a schematic diagram of the molded cell stack pressure test apparatus and battery configuration for an all-solid-state battery (ASSLMB).

[0129] Summary: This paper designs an M-CSE structure to enhance the interfacial stability between the lithium metal anode and the sulfide SSE. This structure ensures uniform lithium deposition and suppresses the formation of lithium dendrites, making it effective under the working conditions of all-solid-state batteries. More importantly, the present invention has successfully realized this structure in 3D-printed sulfide-based solid-state batteries. Generally, sulfide electrolytes (such as LPSCl and Li 9.54 [Si 0.5 Sn 0.5 ]PSBrO) are not fully consistent with the thermodynamic stability of lithium metal. When used independently, these electrolytes tend to form two suboptimal interfaces, namely SEI and MCI. This not only leads to interfacial degradation but also allows lithium dendrite penetration, ultimately affecting battery performance. However, the M-CSE structure exhibits excellent interfacial stability, and its outstanding performance is attributed to the internal inhibition mechanism. During the decomposition of the electrolyte, the internal expansion stress exerts a compressive force on the adjacent electrolyte, effectively inhibiting further decomposition. This self-limiting behavior helps to form a thin and dense interfacial layer, significantly reducing the interfacial impedance and preventing lithium dendrite penetration.

[0130] Li 9.54 [Si 0.5 Sn 0.5 The decomposition of PSBrO not only produces metastable electrolyte particles but also leads to the formation of lithiophilic Li-Si / Sn alloys. These alloys act as lithiophilic seeds in the M-CSE, enhancing lithium kinetics and regulating lithium nucleation, resulting in uniform lithium deposition. This dynamically stable M-CSE interface structure helps balance the electric field and optimize lithium deposition, significantly improving the overall battery performance.

[0131] The experimental results show that thanks to the M-CSE structure, Li / M-CSE-Li 5.3 PS 4.3 Cl 1.7 -M-CSE / Li symmetric battery achieves up to 3.76 mA cm -2 The CCD was obtained and the stable cycling performance was maintained for 650 hours. In addition, the LCO / Li6PS5Cl-M-CSE / Li full cell retained 95.04% of its capacity after 500 cycles at 0.5C. It is worth noting that a 3D printed square cell with a side length of 2 cm was assembled at ultra-low pressure, with a cathode active material ratio of 70% and an area loading of 20 mg cm -2 The battery achieved 128.92mAhg -1 The specific first cycle discharge capacity is up to 170Whkg -1 These findings provide valuable insights into resolving the interfacial stability issue between Li metal anodes and sulfide SSEs.

[0132] In summary, this invention provides a novel solution by leveraging the high adaptability of sulfide-based SSEs and combining the unique advantages of different electrolyte types. By combining advanced design with 3D printing technology, it opens up new possibilities for developing next-generation solid-state electrolyte materials to meet the commercial needs of all-solid-state batteries. This simple and efficient 3D printing manufacturing method lays a solid foundation for the large-scale production and application of all-solid-state batteries and provides a key reference for the future development of battery technology.

[0133] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A composite solid electrolyte, characterized in that The composite solid electrolyte (M-CSE) includes the following components: LPSCl, LSiSnPSBrO, wherein the LSiSnPSBrO is Li 9.54 [Si 0.5 Sn 0.5 ]PSBrO.

2. The composite solid electrolyte according to claim 1, characterized in that The mass fraction of the LSiSnPSBrO is 10 wt % to 30 wt %.

3. The composite solid electrolyte according to claim 1 or 2, characterized in that The LPSCl is Li 5.3 PS 4.3 Cl 1.7 .

4. A method for preparing a composite solid electrolyte according to any one of claims 1 to 3, characterized in that: The preparation method is as follows: LPSCl and LSiSnPSBrO powders are manually ground in an agate mortar at a desired mass ratio for 10 minutes or ball-milled in a planetary ball mill at a desired mass ratio for 10 minutes to obtain the composite solid electrolyte (M-CSE).

5. An all-solid-state battery, characterized in that: The invention comprises a negative electrode, an M-CSE layer and a positive electrode, wherein the M-CSE layer is made of the composite solid electrolyte according to any one of claims 1 to 3.

6. The all-solid-state battery according to claim 5, characterized in that: The positive electrode is a composite positive electrode, and the preparation method of the composite positive electrode is as follows: the positive electrode material is obtained by ball milling LCO, VGCF and LPSCl with a mass ratio of 60:5:35 at a rotation speed of 100 rpm for 0.2 h, and the LPSCl is Li6PS5Cl.

7. The all-solid-state battery according to claim 6, characterized in that The preparation method of the Li6PS5Cl is as follows: Li2S, P2S5 and LiCl are mixed in a molar ratio of 5:1:2, the mixture is ball-milled at a speed of 600 rpm for 12 hours, sintered at 550°C for 12 hours under an argon atmosphere at a heating rate of 5°C / min, and finally pulverized to obtain Li6PS5Cl.

8. The all-solid-state battery according to claim 7, characterized in that: There is a SE layer between the positive electrode and the M-CSE layer, and the SE layer is composed of Li6PS5Cl or Li 5.3 PS 4.3 Cl 1.7 Made.

9. A method for preparing an all-solid-state battery, characterized in that: The preparation method comprises the following steps: (1) Add 60 mg of Li6PS5Cl or Li 5.3 PS 4.3 Cl 1.7 Pressed into a 10 mm diameter disc under a pressure of 124 MPa to form the SE layer; (2) Place 10 mg of the composite positive electrode on one side of the SE layer and press it at a pressure of 496 MPa for 2 minutes to make the two fit tightly together; (3) 20 mg of pre-synthesized M-CSE was placed on the other side of the SE layer and pressed at a pressure of 868 MPa for 2 min to form an M-CSE layer, which was tightly bonded to the SE layer; (4) A 10 mm lithium sheet is placed on the other side of the M-CSE layer, where the lithium sheet serves as the lithium metal negative electrode, and the all-solid-state battery is assembled; The M-CSE material is the composite solid electrolyte according to any one of claims 1 to 3.

10. A method for preparing a 3D printed soft-pack battery, characterized in that: The preparation method comprises the following steps: Step S1: Take a certain amount of composite positive electrode, negative electrode, electrolyte and M-CSE materials; add 8% by mass of nitrile rubber (NBR) to the composite positive electrode, electrolyte and M-CSE respectively to prepare positive electrode printing slurry, electrolyte printing slurry and M-CSE printing slurry; Step S2: Place the positive electrode printing slurry, electrolyte printing slurry, and M-CSE printing slurry into multiple nozzles of a 3D printer, respectively. By switching the nozzles, M-CSE, electrolyte, and composite positive electrode are printed on the negative electrode in sequence. Step S3: Adding aluminum-plastic film to the outside of the printed battery structure to complete the packaging; Step S4: isostatically compacting at 2 MP to obtain a 3D printed soft-pack battery; The preparation method of the composite positive electrode is as follows: the positive electrode material is obtained by ball milling LCO, VGCF and LPSCl with a mass ratio of 60:5:35 at a rotation speed of 100 rpm for 0.2 h; The negative electrode is a copper-lithium composite strip, wherein the thickness of the lithium strip is 20 μm and the thickness of the copper strip is 20 μm; The electrolyte is Li 5.3 PS 4.3 Cl 1.7 ; The M-CSE material is the composite solid electrolyte according to any one of claims 1 to 3.

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