Preparation method of all-solid-state battery and all-solid-state battery

Abstract

The invention discloses a preparation method of an all-solid-state battery and the all-solid-state battery, and relates to the technical field of solid-state batteries. The positive electrode material is a composite system material based on a lithium-rich manganese-based oxide and an ultra-high nickel ternary material, cation mixing in the circulation process is effectively inhibited through single crystallization treatment, and a Li < + > directional transport channel is formed through an ultra-high nickel layer; the negative electrode material is a pre-lithiated silicon-carbon composite negative electrode, a graphitized carbon shell layer is constructed on a porous silicon-carbon substrate, and a pre-lithiation agent is introduced, so that the silicon-based expansion rate is remarkably reduced, and the cycle performance is improved; the inorganic filler, the lithium salt and the functional additive are introduced into the composite solid electrolyte, so that the safety performance is improved, and thermal runaway is prevented. By utilizing the positive electrode material, the negative electrode material and the composite solid electrolyte provided by the invention, the interface impedance can be reduced, the thermal runaway safety performance of the battery monomer is effectively improved, the potential safety hazard of thermal runaway is fundamentally solved, the high efficiency of battery preparation is improved, and the practical and application values are relatively good.

Description

Technical Field

[0001] The present invention relates to the technical field of solid-state batteries, and in particular to a method for preparing an all-solid-state battery and an all-solid-state battery. Background Art

[0002] As the "energy heart" of new energy vehicles, power batteries, through technological advancements, have become a core driver of the automotive industry's electrification transformation. Lithium iron phosphate (LFP) has been widely used due to its excellent electrochemical performance. Innovations such as CTP3.0 assembly technology, composite current collector processes, and dry electrode preparation have significantly increased the volume utilization of LFP systems, significantly improving energy density and cycle life. All-solid-state batteries, which utilize solid-state electrolytes (SSEs) instead of traditional liquid electrolytes, offer advantages such as high safety, high energy density, and long cycle life, making them a core direction for next-generation energy storage technologies.

[0003] Currently, existing all-solid-state battery manufacturing processes still need to address core issues such as interfacial impedance, large-scale production, and cost control. There is an urgent need to develop processes that can achieve efficient all-solid-state battery manufacturing while reducing interfacial impedance and effectively improving the thermal runaway safety performance of battery cells.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for preparing an all-solid-state battery and an all-solid-state battery, aiming to effectively reduce the interface impedance, improve the thermal runaway safety performance of the battery cell, and realize the efficient preparation of the all-solid-state battery.

[0006] The present invention is achieved in that: In a first aspect, the present invention provides a method for preparing an all-solid-state battery, comprising: Preparation of cathode materials: The lithium-rich manganese-based oxide is subjected to single crystal treatment, and then coated with ultra-high nickel ternary cathode materials to obtain a core-shell precursor. The core-shell precursor is mixed with a lithium source and subjected to gradient sintering; Preparation of negative electrode materials: constructing a graphitized carbon shell on a porous silicon-carbon substrate by chemical vapor deposition to obtain a carbon-coated porous material, and mixing the carbon-coated porous material with a pre-lithiation agent; Preparation of composite solid electrolytes: Inorganic fillers, lithium salts and functional additives are introduced into the polymer matrix, and the solid electrolyte is prepared by solution casting or hot pressing process; Battery integration: Use positive electrode materials, negative electrode materials and composite solid electrolytes to prepare battery cells and perform battery integration.

[0007] In an optional embodiment, the process of preparing the positive electrode material includes: calcining the lithium-rich manganese-based oxide in an oxygen-containing atmosphere to obtain single crystal particles; epitaxially growing LiNi on the surface of the single crystal particles by atomic layer deposition. 0.92 Co 0.04 Al 0.04 The core-shell precursor is mixed with a lithium source and sintered at 730°C to 780°C for one stage, and then sintered at 820°C to 880°C for a second stage.

[0008] In an optional embodiment, the process for preparing the positive electrode material has at least one of features A1 to F1: Feature A1: During the preparation of the single crystal particles, the calcination temperature is controlled to be 920°C-980°C, the calcination time is 10 hours-15 hours, and the calcination atmosphere is an oxygen-containing atmosphere; Feature B1: Growth of LiNi 0.92 Co 0.04 Al 0.04 The O2 shell process includes: using oxygen-containing gas as the reaction gas and using nickel source, cobalt source and aluminum source to perform element alternating deposition; Feature C1: Controlled formation of LiNi 0.92 Co 0.04 Al 0.04 The thickness of the O2 shell is 4nm-6nm; Feature D1: Growth of LiNi 0.92 Co 0.04 Al 0.04 During the O2 shell process, the reaction temperature is controlled at 200°C-300°C, the pulse time is 0.05s-0.20s, and the number of cycles is 40-60 times; Feature E1: Control the sintering time of one stage to be 4h-8h, the oxygen flow rate to be 1L / min-3L / min, and the heating rate to be 4℃ / min-6℃ / min; Feature F1: The sintering time of the second stage sintering is controlled to be 6h-10h, the oxygen flow rate is 4L / min-6L / min, and the heating rate is 1℃ / min-3℃ / min.

[0009] In an optional embodiment, the process of preparing the negative electrode material includes: using a silicon source and a carbon source as main raw materials, preparing a porous silicon-carbon matrix by a sol-gel method; placing the porous silicon-carbon matrix in a furnace body, introducing a mixed gas of acetylene and hydrogen, performing chemical vapor deposition to form a graphitized carbon layer, and obtaining a carbon-coated porous material; and ball-milling the carbon-coated porous material and a pre-lithiation agent.

[0010] In an optional embodiment, the process for preparing the negative electrode material has at least one of features A2 to G2: Feature A2: The silicon source is ethyl orthosilicate, the carbon source is sucrose, and the mass ratio of the silicon source to the carbon source is 1:(0.5-1.0); Feature B2: During the preparation of the porous silicon-carbon matrix, the carbonization temperature is controlled to be 850°C-950°C and the carbonization time is controlled to be 3h-5h under an inert atmosphere; Feature C2: The pore size distribution of the porous silicon carbon matrix is ​​20nm-50nm, and the porosity is 60%-70%; Feature D2: Control the thickness of the graphitized carbon layer to 3nm-5nm; Feature E2: During the formation of the graphitized carbon layer, the deposition temperature is controlled to be 780°C-820°C and the deposition time is 10 min-15 min; Feature F2: During the formation of the graphitized carbon layer, the volume ratio of acetylene to hydrogen is controlled to be 1:(2-4); Feature G2: The pre-lithiation agent is Li5FeO4, and the mass ratio of the carbon-coated porous material to the pre-lithiation agent is 100:(8-12).

[0011] In an optional embodiment, polyethylene oxide, an inorganic filler, a lithium salt and a functional additive are mixed, and a solid electrolyte is prepared by a solution casting or hot pressing process.

[0012] In an optional embodiment, the process for preparing the solid electrolyte has at least one of features A3 to D3: Feature A3: Inorganic filler is cubic phase Li 6.4 Al 0.2 La3Zr2O 12 , before adding, high-energy ball milling surface treatment is carried out, the speed is controlled at 400rpm-600rpm, the ball-to-material ratio is (15-25):1; the volume ratio of inorganic filler to polyethylene oxide is (15-25):100; Feature B3: The lithium salt includes LiFSI and LiPF6, and the concentration of LiFSI is controlled to be 0.8M-1.2M, and the concentration of LiPF6 is controlled to be 0.1M-0.3M; Feature C3: The functional additives include trimethyl borate, fluoroethylene carbonate, methyl propionate, vinylene carbonate, and polybenzyl methacrylate. The amount of trimethyl borate added is 1 wt%-3 wt%, the amount of fluoroethylene carbonate added is 2 wt%-4 wt%, the amount of methyl propionate added is 4 wt%-6 wt%, the amount of vinylene carbonate added is 0.5 wt%-1.5 wt%, and the amount of polybenzyl methacrylate added is 2 wt%-4 wt%. Feature D3: After mixing the raw materials and the solvent, the mixture is cast into a film at 50°C-70°C, and then hot-pressed at 70°C-90°C.

[0013] In an optional embodiment, module-free battery integration technology is used for battery integration, and after battery integration, a 3D microstructure is constructed on the surface of the positive and negative electrodes by laser etching technology.

[0014] In an optional embodiment, the wavelength of the laser etching is controlled to be 1060 nm-1070 nm, the power is controlled to be 15 W-25 W, and the aperture of the 3D microstructure is controlled to be 10 μm-30 μm.

[0015] In a second aspect, the present invention provides an all-solid-state battery prepared by the preparation method of any one of the aforementioned embodiments.

[0016] The present invention has the following beneficial effects: the positive electrode material is a composite system material based on lithium-rich manganese-based oxide and ultra-high nickel ternary material, which effectively inhibits the mixed arrangement of cations in the cycle process through single crystal treatment, and forms Li through the ultra-high nickel layer. + Directed transport channel; the negative electrode material is a pre-lithiated silicon-carbon composite negative electrode, which constructs a graphitized carbon shell on a porous silicon-carbon matrix and introduces a pre-lithiation agent, significantly reducing the silicon-based expansion rate and improving cycle performance; inorganic fillers, lithium salts, and functional additives are introduced into the composite solid electrolyte to enhance safety performance and prevent thermal runaway. Utilizing the positive electrode material, negative electrode material, and composite solid electrolyte provided by the present invention can reduce interfacial impedance, effectively improve the thermal runaway safety performance of battery cells, fundamentally resolve the potential safety hazards of thermal runaway, improve the efficiency of battery preparation, and have good practical and application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 Preparation process of composite system materials for ultra-high nickel ternary materials; Figure 2 Preparation process of lithiated silicon-carbon composite negative electrode materials; Figure 3 Preparation processes for solid-state electrolytes and power batteries; Figure 4 This is the SEM image of the lithiated silicon-carbon composite negative electrode material; Figure 5Figure 1 is a solid electrolyte modification process; A shows the use of lithium salts in place of solvents to achieve higher mechanical toughness in SIC solid-phase extraction. The resulting SPE is called SR-SPE; B shows the slidable cross-linked structure that prevents stress concentration in the PEO chains during stretching; C shows the formation of planar zigzag crystals of PEO; D shows the control of PEO crystallinity by varying the salt concentration; E shows the phase separation of CDs within the SR network. DETAILED DESCRIPTION

[0019] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, all are conventional products that can be purchased commercially.

[0020] An embodiment of the present invention provides a method for preparing an all-solid-state battery, comprising the following steps: S1. Preparation of positive electrode materials Please refer to Figure 1 The purchased or independently prepared lithium-rich manganese-based oxide (LLMO) is subjected to single crystal processing, and then coated with ultra-high nickel ternary positive electrode material to obtain a core-shell precursor. The core-shell precursor is mixed with a lithium source and gradient sintered to obtain a positive electrode material with excellent electrochemical properties.

[0021] It should be noted that the lithium-rich manganese-based oxide can suppress cation mixing after single crystal treatment ((003) crystal plane half-height width ≤ 0.08°); coating with ultra-high nickel layer can form Li + Directed transport channel (ionic conductivity ≥ 10 -3 This architecture utilizes the high reversible capacity of LLMO (≥300mAh / g) and the high compaction density of ultra-high nickel materials (≥4.2g / cm 3 ) synergistic effect, prepared by co-precipitation-gradient sintering (750-850℃) process, the composite positive electrode has a capacity retention rate of >90% after 500 cycles at 1C within the voltage window of 2.0-4.8V, and reduces the risk of interfacial oxygen precipitation (DSC peak temperature is increased to 280℃).

[0022] Specifically, the positive electrode adopts layered LLMO (xLi2MnO3·(1-x)LiMO2, 0.2≤x≤0.5) and ultra-high nickel ternary positive electrode materials (such as LiNi 0.92 Co 0.04 Al 0.04 O2) to build a core-shell structure. LLMO can be specifically Li 1.2 Mn 0.54 Ni 0.13 Co 0.13O2 (x=0.4) can be purchased commercially or synthesized by conventional co-precipitation method.

[0023] In some embodiments, a lithium-rich manganese-based oxide is calcined in an oxygen-containing atmosphere to obtain single-crystalline particles. LLMO employs a gradient lithium vacancy design to enhance lattice stability. Through single crystallization, the (003) crystal plane half-width is reduced to 0.08°, effectively suppressing cation mixing. During the preparation of the single-crystalline particles, a high-temperature solid-phase calcination method is employed, with the calcination temperature controlled to be between 920°C and 980°C, such as 920°C, 930°C, 940°C, 950°C, 960°C, 970°C, and 980°C. The calcination time is between 10 hours and 15 hours, such as 10 hours, 11 hours, 12 hours, 13 hours, 14 hours, and 15 hours. The calcination atmosphere is an oxygen-containing atmosphere, such as oxygen.

[0024] In some embodiments, an atomic layer deposition system (ALD, Cambridge NanoTech Savannah S200) is used to epitaxially grow LiNi on the surface of single crystal particles using the atomic layer deposition method. 0.92 Co 0.04 Al 0.04 O2 shell, through heterogeneous interface engineering to build core-shell structure. 0.92 Co 0.04 Al 0.04 The thickness of the O2 shell is 4nm-6nm, such as 4.0nm, 4.5nm, 5.0nm, 5.5nm, 6.0nm, etc. The shell is epitaxially grown with a 4-6nm ultra-high nickel layer by atomic layer deposition (ALD) technology to form Li + Directed transport channel (ionic conductivity ≥ 10 -3 S / cm).

[0025] Furthermore, the growth of LiNi 0.92 Co 0.04 Al 0.04 The O2 shell process includes: using oxygen-containing gas as the reaction gas, and using nickel, cobalt, and aluminum sources to alternately deposit elements. During the deposition process, the reaction temperature is controlled to be 200°C-300°C, such as 200°C, 230°C, 250°C, 280°C, and 300°C; the pulse time is 0.05s-0.20s, such as 0.05s, 0.10s, 0.15s, and 0.20s; and the number of cycles is 40-60 times, such as 40 times, 45 times, 50 times, 55 times, and 60 times.

[0026] Specifically, the nickel source can be Ni(dmamp)2 (nickel bis(dimethylaminomethylpropyl)), but is not limited thereto. The oxygen-containing gas can be oxygen, a reactive gas used to oxidize the precursor, form Ni-O bonds, and remove ligands. The lithium, cobalt, and aluminum sources are alternately introduced with precursors such as Li(thd), Co(acac)3, and Al(CH3)3 (TMA) to precisely control the NCA composition. The composition is controlled by adjusting the number of Ni / Co / Al precursor cycles (e.g., 92:4:4). Post-deposition annealing allows Li to diffuse into the lattice, forming a layered structure. For example, a cycle count of 50 refers to adjusting the number of Ni / Co / Al precursor cycles.

[0027] In some embodiments, a co-precipitation-gradient sintering process is used to mix the core-shell precursor with a lithium source (lithium excess, such as 5% excess) and first perform a first-stage sintering at 730°C-780°C for 4h-8h, followed by a second-stage sintering at 820°C-880°C for 6h-10h. Co-precipitation-gradient sintering can achieve a capacity retention of >90% after 500 1C cycles, and a DSC oxygen precipitation peak of 280°C. During the first sintering, the oxygen flow rate is controlled to 1L / min-3L / min and the heating rate is 4°C / min-6°C / min; during the second sintering, the oxygen flow rate is controlled to 4L / min-6L / min and the heating rate is 1°C / min-3°C / min. By regulating the oxygen flow rate and heating rate of the two-stage sintering, the compaction density of the material after sintering is increased, the specific surface area is reduced, and the interface side reactions are effectively suppressed.

[0028] Specifically, during the first sintering process, the sintering temperature can be controlled to be 730°C, 750°C, 780°C, etc., the sintering time can be 4h, 6h, 8h, etc., the oxygen flow rate can be 1L / min, 2L / min, 3L / min, etc., and the heating rate can be 4°C / min, 5°C / min, 6°C / min, etc. During the second sintering process, the sintering temperature can be controlled to be 820°C, 850°C, 880°C, etc., the sintering time can be 6h, 8h, 10h, etc., the oxygen flow rate can be 4L / min, 5L / min, 6L / min, etc., and the heating rate can be 1°C / min, 2°C / min, 3°C / min, etc. The amount of lithium source is calculated based on the amount of lithium in the inner shell, so that the total lithium content is greater than the theoretical amount of lithium. For example, an excess of 5% means that the total amount of lithium is 1.05 times the theoretical amount.

[0029] S2. Preparation of negative electrode materials Please refer to Figure 2, a graphitized carbon shell is constructed on a porous silicon-carbon matrix by chemical vapor deposition to obtain a carbon-coated porous material. The carbon-coated porous material is mixed with a pre-lithiation agent to obtain a negative electrode material with low silicon expansion rate and high first efficiency. This composite structure controls the silicon-based expansion rate within 15% (pure silicon>300%) through the topological constraint effect of the carbon layer, and the pre-lithiation agent releases Li during the first charge. + (Theoretical compensation capacity 520mAh / g), the first coulombic efficiency of the half-cell was increased to 92% (control group <82%), and the specific capacity retention rate was >85% after 200 cycles at 0.5C (N / P=1.15, surface density 3.2mAh / cm 2 ).

[0030] In some embodiments, a porous silicon-carbon matrix is ​​prepared using a silicon source and a carbon source as primary raw materials via a sol-gel method. The resulting porous SiOx / C matrix has a pore size distribution of 20 nm to 50 nm and a porosity of 60% to 70% (as verified by BET surface area measurements). The silicon source can be, but is not limited to, ethyl orthosilicate; the carbon source can be, but is not limited to, sucrose; and the mass ratio of the silicon source to the carbon source is 1:(0.5-1.0), such as 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1.0, and the like.

[0031] Furthermore, during the preparation of the porous silicon-carbon matrix, the carbonization temperature is controlled to be 850°C-950°C and the carbonization time is controlled to be 3-5 hours under an inert atmosphere to form a three-dimensional interpenetrating network structure. The inert atmosphere can be nitrogen, argon, etc.; the carbonization temperature can be 850°C, 880°C, 900°C, 930°C, 950°C, etc.; and the carbonization time can be 3 hours, 4 hours, 5 hours, etc.

[0032] In some embodiments, chemical vapor deposition (CVD) can be used to construct the graphitized carbon shell. The specific steps are as follows: a porous silicon-carbon substrate is placed in a tube furnace and introduced with a mixture of acetylene (C2H2) and hydrogen, with the volume ratio of acetylene to hydrogen controlled to be 1:(2-4). Chemical vapor deposition is performed at 780°C-820°C for 10-15 minutes to form a graphitized carbon layer with a thickness of 3-5 nm. The resulting carbon-coated porous material exhibits a Raman spectrum of ID / IG = 0.12 and an electrical conductivity >100 S / cm. Transmission electron microscopy (TEM) reveals that the carbon layer uniformly coats the surface of the silicon particles, forming a continuous conductive network.

[0033] Specifically, the volume ratio of acetylene to hydrogen can be 1:2, 1:3, 1:4, etc.; the deposition temperature of chemical vapor deposition can be 780°C, 800°C, 820°C, etc., and the deposition time can be 10 minutes, 13 minutes, 15 minutes, etc. The thickness of the prepared graphitized carbon layer can be 3 nm, 4 nm, 5 nm, etc.

[0034] In some embodiments, the carbon-coated porous material obtained after constructing the graphitized carbon shell is mixed with a pre-lithiation agent by ball milling. The pre-lithiation agent can be Li5FeO4. The mass ratio of the carbon-coated porous material to the pre-lithiation agent is 100:(8-12), such as 100:8, 100:10, 100:12, etc. 8-12wt% of the pre-lithiation agent Li5FeO4 (D50=3μm, XRD verified cubic phase structure) is introduced in combination with the mechanical ball milling process. The pre-lithiation agent releases Li during the first charge. + , thereby improving the initial coulombic efficiency of the half-cell and the specific capacity retention rate. Specifically, the ball mill can be a planetary ball mill, with a rotation speed controlled at 200 rpm to 400 rpm, a ball-to-material ratio controlled at (8-12):1, and a ball milling time of 2 hours to 6 hours.

[0035] S3. Preparation of composite solid electrolyte Please refer to Figure 3 Inorganic fillers, lithium salts and functional additives are introduced into the polymer matrix and the solid electrolyte is prepared by solution casting or hot pressing process, which can significantly reduce the interface impedance. The polymer matrix can be polyethylene oxide (PEO, weight average molecular weight 5×10 6 ~1×10 7 ), constructing a continuous phase three-dimensional network substrate, and achieving flexible support and electrode interface chemical adaptation (contact angle <10°) through solution casting / hot pressing (phase separation temperature 60-80°C). In actual operation, polyethylene oxide (PEO), inorganic fillers, lithium salts, and functional additives are mixed and prepared using solution casting or hot pressing processes to prepare the solid electrolyte.

[0036] In some embodiments, the inorganic filler may be a cubic phase Li 6.4 Al 0.2 La3Zr2O 12 Garnet electrolyte (LLZO, D50 = 200nm) is used as a rigid filler. Prior to incorporation, the surface of the filler is hydroxylated by high-energy ball milling. The milling speed is controlled between 400 rpm and 600 rpm, and the ball-to-material ratio is (15-25):1. The volume ratio of the inorganic filler to polyethylene oxide is (15-25):100. The introduction of the surface-hydroxylated inorganic filler dispersed within the PEO matrix forms a percolation network, resulting in an ionic conductivity of 1.2 mS / cm (25°C) and a mechanical strength of >18 MPa. Specifically, the volume ratio of the inorganic filler to polyethylene oxide can be 15:100, 18:100, 20:100, 23:100, or 25:100. The milling speed can be 400 rpm, 500 rpm, or 600 rpm, and the ball-to-material ratio can be 15:1, 18:1, 20:1, 23:1, or 25:1.

[0037] In some embodiments, the lithium salt includes LiFSI (lithium bis(fluorosulfonyl)imide) and LiPF6, and the concentration of LiFSI is controlled to be 0.8M-1.2M, such as 0.8M, 1.0M, 1.2M, etc.; the concentration of LiPF6 is controlled to be 0.1M-0.3M, such as 0.1M, 0.2M, 0.3M, etc. The lithium salt system uses 1.0MLiFSI as the main salt (dissociation degree > 95%) and is compounded with 0.2M LiPF6 to form a LiF-Li2O gradient SEI (XPS detection of F / O atomic ratio > 2.5). The oxidation potential is > 5.2V vsLi+ / Li after cyclic voltammetry testing (0.1mV / s), and the interfacial impedance is stable at < 50Ω·cm after 500h of cycling. 2 (EIS test frequency 10mHz-1MHz).

[0038] In some embodiments, the functional additives include trimethyl borate (TMB), fluoroethylene carbonate (FEC), methyl propionate, vinylene carbonate (VC), and polybenzyl methacrylate. The amount of trimethyl borate added is 1 wt%-3 wt%, such as 1 wt%, 2 wt%, 3 wt%, etc.; the amount of fluoroethylene carbonate added is 2 wt%-4 wt%, such as 2 wt%, 3 wt%, 4 wt%, etc.; the amount of methyl propionate added is 4 wt%-6 wt%, such as 4 wt%, 5 wt%, 6 wt%, etc.; the amount of vinylene carbonate added is 0.5 wt%-1.5 wt%, such as 0.5 wt%, 1.0 wt%, 1.5 wt%, etc.; and the amount of polybenzyl methacrylate added is 2 wt%-4 wt%, such as 2 wt%, 3 wt%, 4 wt%, etc.

[0039] It should be noted that the addition of trimethyl borate (TMB) and fluoroethylene carbonate (FEC) improves high-voltage compatibility, widening the electrochemical window to above 5V and matching high-voltage cathodes. The introduction of low-melting-point solvents (such as methyl propionate) and low-temperature film-forming agents (such as VC) into the solid-state electrolyte can broaden the temperature range of performance, allowing the battery to maintain more than 80% of its capacity within the range of -40°C to 80°C. The integration of thermally responsive polymers (such as polybenzyl methacrylate) into the solid-state electrolyte can enhance intelligent safety performance. When the temperature exceeds 90°C, an insulating layer automatically forms to block ion transmission and prevent thermal runaway.

[0040] In some embodiments, after mixing the raw materials and solvent, a film is cast at 50°C-70°C, followed by hot pressing at 70°C-90°C to form a continuous three-dimensional network structure (contact angle <8°), achieving chemical adaptation of the electrode interface. The film casting temperature can be 50°C, 60°C, 70°C, etc.; the hot pressing temperature can be 70°C, 80°C, 90°C, etc. The type of solvent is not limited, and can be, for example, acetonitrile, but is not limited thereto.

[0041] S4. Battery Integration The battery cells are prepared using positive electrode materials, negative electrode materials and composite solid electrolytes, and battery integration is carried out. The various components of the power battery prepared above are combined to prepare a complete all-solid-state lithium-ion battery, and its electrical performance is tested to complete performance evaluation, improve design solutions and assembly processes.

[0042] In some embodiments, module-free battery integration technology (CTP3.0 technology) is used for battery integration. After battery integration, 3D microstructures are constructed on the positive and negative electrode surfaces using laser etching. Using CTP (Cell to Pack) 3.0 technology and a full-tab design, the module layer is reduced, increasing volume utilization to over 75%, and achieving a system energy density exceeding 600Wh / L. Laser etching is used to construct 3D microstructures on the positive and negative electrode surfaces. Interface engineering is performed to increase the contact area between the active material and the electrolyte, reducing interfacial impedance. A thermally responsive polymer (90°C phase transition) is used to prevent thermal runaway. Leveraging relevant solid-state power battery production and analysis methods and technologies, the efficiency of battery preparation is improved. This solid-state battery preparation method has significant practical and application value.

[0043] In some embodiments, in the process of constructing 3D microstructures on the surfaces of the positive and negative electrodes through laser etching technology, the wavelength of laser etching is controlled to be 1060nm-1070nm, such as 1060nm, 1065nm, 1070nm, etc.; the power is 15W-25W, such as 15W, 20W, 25W, etc.; the pore size of the 3D microstructure is 10μm-30μm, such as 10μm, 20μm, 30μm, etc.

[0044] An embodiment of the present invention also provides an all-solid-state battery, which is prepared by the preparation method provided by the embodiment of the present invention. By improving the positive electrode material, negative electrode material, and composite solid electrolyte, the product quality is greatly improved. At the same time, it can directly guide the design improvement of electric vehicles and power batteries from a mechanistic perspective, help to improve the life and safety of electric vehicles and batteries, and further promote their commercial application.

[0045] Specifically, the all-solid-state battery provided by the embodiments of the present invention has the following advantages: (1) The positive electrode material of the battery has the following advantages: high energy density, the theoretical capacity of lithium-rich manganese-based materials exceeds 250mAh / g, and ultra-high nickel ternary materials (NCA) can further improve the voltage platform, and the comprehensive energy density can reach more than 400Wh / kg; high stability, the surface coating layer inhibits the oxygen release problem of lithium-rich materials during circulation and improves structural stability; the preparation process is optimized, and the atomic layer deposition (ALD) technology is used to coat the LiAlO2 nanolayer to reduce interface side reactions and enhance the lithium ion diffusion rate.

[0046] (2) The negative electrode material of the battery has the following advantages: the capacity is greatly improved compared with general batteries. The theoretical capacity of the silicon-based negative electrode reaches 4200mAh / g (pure silicon). After the composite structure design, the actual capacity can be increased to 1500mAh / g, which is significantly higher than traditional graphite (372mAh / g); the volume expansion is suppressed, the porous silicon structure and the carbon layer buffer the volume expansion (<20%), and pre-lithiation compensates for the lithium loss in the first cycle, extending the cycle life to more than 2000 times; the interface is optimized, and the solid electrolyte interface (SEI) in situ generation technology is adopted. A flexible SEI film is formed by electrolyte additives (such as LiDFOB) to adapt to the dynamic volume changes of the silicon negative electrode.

[0047] (3) The all-solid-state electrolyte design completely eliminates the risk of leakage and combustion of liquid electrolytes and has excellent high-temperature resistance (the upper limit of the operating temperature is increased to 120°C). This electrolyte improves fast charging capabilities. The high ion mobility of LLZO and the low viscosity of LiFSI work synergistically to support 5C fast charging (charging to 80% in 20 minutes).

[0048] (4) It can effectively improve the thermal runaway safety performance of battery cells and fundamentally solve the potential safety hazards of thermal runaway. It can further reduce the product testing links in the battery production process and simplify some manufacturing processes, thereby effectively improving production efficiency. It can shorten the cycle from product conception to production, reduce errors and reduce costs. At the same time, it can form an empirical analysis model and apply it to the design and optimization of other related manufacturing fields. This method is original and scalable. The positive electrode adopts a cobalt-free design, and the negative electrode uses an easily separable silicon-carbon composite material. Combined with the hydrothermal recycling process, it is highly recyclable and friendly, achieving a material recycling rate of over 95%.

[0049] The features and performance of the present invention are further described in detail below with reference to the embodiments.

[0050] Example 1 This embodiment provides a method for preparing a lithium-rich manganese-based / ultra-high nickel ternary core-shell composite positive electrode material, the steps of which are as follows: (1) Preparation of core-shell structure precursor The lithium-rich manganese-based oxide (LLMO) core precursor was synthesized by co-precipitation method, and the specific chemical composition was Li1.2 Mn 0.54 Ni 0.13 Co 0.13 O2 (x=0.4), the specific synthesis steps refer to Pan et al., Nat. Mater. 2015 and Yu et al., Adv. Mater. 2020.

[0051] The precursor was subjected to single crystal treatment and calcined at 950°C for 12 hours in an oxygen atmosphere using a high-temperature solid-phase method to obtain single crystal particles with a (003) crystal plane half-width ≤ 0.08°.

[0052] (2) ALD epitaxial growth of ultra-high nickel layer An atomic layer deposition system (ALD, Cambridge NanoTech Savannah S200) was used to epitaxially grow LiNi on the surface of the LLMO core using Ni(dmamp)2 (bis(dimethylaminomethylpropyl)nickel), Li(thd), Co(acac)3, and Al(CH3)3 as precursors and O2 as the reaction gas. 0.92 Co 0.04 Al 0.04 The deposition parameters were set as follows: reaction temperature 250°C, pulse duration 0.1s, and 50 cycles, ultimately forming a continuous coating layer 4.8±0.3nm thick. SEM-EDS scanning revealed a Ni concentration gradient of 92.4±1.2% in the outer shell.

[0053] (3) Co-precipitation-gradient sintering process The core-shell precursor was mixed with LiOH·H2O (5% excess lithium) and sintered in a two-stage gradient manner: Stage 1: 750°C / 6h, oxygen flow rate 2L / min, heating rate 5°C / min; The second stage: 850℃ / 8h, oxygen flow rate 5L / min, heating rate 2℃ / min.

[0054] After testing, the compaction density of the sintered material reaches 4.25g / cm 3 , the BET specific surface area is reduced to 1.2m² / g, effectively inhibiting interfacial side reactions.

[0055] Example 2 This embodiment provides a method for preparing a pre-lithiated silicon-carbon composite negative electrode material, the steps of which are as follows: (1) Preparation of nanoporous silicon substrate A porous SiOx / C matrix was synthesized using a sol-gel method. The mass ratio of the silicon source (tetraethyl orthosilicate) to the carbon source (sucrose) was adjusted to 1:0.8. The matrix was then carbonized at 900°C for 4 hours under an argon atmosphere to form a three-dimensional interpenetrating network. The detailed steps are described in: Acid-catalyzed sol-gel method for controlling mesoporous structure (ACS Nano 2019, 13, 950) and Optimizing the carbon source ratio for improved cycling stability (Energy Storage Mater. 2020, 28, 307).

[0056] After testing, the pore size distribution of the synthesized nanoporous silicon matrix is ​​20-50nm, and the porosity is 65±5% (verified by BET specific surface area test).

[0057] (2) Chemical vapor deposition (CVD) to construct graphitized carbon shell The SiOx / C substrate was placed in a tube furnace and CVD deposited at 800°C using a mixture of acetylene (C2H2) and hydrogen (1:3 by volume). By adjusting the deposition time (12 minutes), a graphitized carbon layer with a thickness of 3-5 nm was obtained.

[0058] Raman spectroscopy revealed an ID / IG ratio of 0.12, and electrical conductivity >100 S / cm. Transmission electron microscopy (TEM) revealed a uniform carbon layer coating the surface of the silicon particles, forming a continuous conductive network.

[0059] (3) Introduction of pre-lithiation agent by mechanical ball milling Li5FeO4 powder (D50 = 3 μm, cubic phase structure verified by XRD) was mixed with the above composite particles at a ratio of 10 wt% and processed in a planetary ball mill (rotation speed 300 rpm, ball-to-material ratio 10:1) for 4 hours.

[0060] SEM-EDS analysis showed that Li5FeO4 was uniformly dispersed on the surface of the carbon shell to form Li + Release active sites. Figure 4 shown.

[0061] Example 3 This embodiment provides a method for preparing a composite solid electrolyte and an all-solid-state battery, and the steps are as follows: Step 1: Preparation of polymer-inorganic composite electrolyte (1) Base construction: using a weight average molecular weight of 7.5×10 6 Polyethylene oxide (PEO) was dissolved in acetonitrile solvent (concentration 15wt%) and formed into a film at 60°C by solution casting, and then hot-pressed at 80°C to form a continuous three-dimensional network structure (contact angle <8°), achieving chemical adaptation of the electrode interface.

[0062] (2) Inorganic filler modification: cubic phase Li6.4 Al 0.2 La3Zr2O 12 (LLZO, D50=200nm) was surface hydroxylated by high-energy ball milling (speed 500rpm, ball-to-material ratio 20:1) and dispersed in the PEO matrix at a volume fraction of 20%, forming a percolation network with an ionic conductivity of 1.2mS / cm (25℃) and a mechanical strength of >18MPa.

[0063] (3) Optimization of lithium salt system: 1.0M LiFSI (97% dissociation degree) and 0.2M LiPF6 were combined. XPS analysis showed that the F / O atomic ratio in the SEI film reached 2.8. The oxidation potential in the cyclic voltammetry test (0.1mV / s) increased to 5.3V vs Li+ / Li. The interfacial impedance stabilized at 45Ω·cm² after 500h of cycling (EIS frequency range 10mHz-1MHz).

[0064] Step 2: Functional Additive Integration (1) High voltage adaptation modification: 2 wt% trimethyl borate (TMB) and 3 wt% fluoroethylene carbonate (FEC) were added to broaden the electrochemical window to 5.2 V through intermolecular complexation, matching LiNi 0.92 Co 0.04 Al 0.04 O2 high voltage positive electrode.

[0065] (2) Wide temperature range regulation: 5 wt% methyl propionate (melting point -87 °C) and 1 wt% vinylene carbonate (VC) were introduced to lower the glass transition temperature (DSC test Tg = -55 °C), so that the battery capacity retention rate in the temperature range of -40 ~ 80 °C is greater than 83%.

[0066] (3) Thermal safety design: 3 wt% polybenzyl methacrylate (phase transition temperature 90 °C) is added. When the temperature exceeds the threshold, an insulating layer is formed (SEM observation thickness > 200 nm), blocking the ion transmission path, and the DSC thermal runaway trigger temperature is increased to 285 °C.

[0067] In actual operation, the specific steps of step 1 and step 2 are as follows: take the weight average molecular weight of 7.5×10 6 Polyethylene oxide (PEO) was dissolved in acetonitrile solvent (concentration 15wt%), and the modified Li 6.4 Al 0.2 La3Zr2O 12 , add LiFSI, LiPF6, add trimethyl borate (TMB) and 3wt% fluoroethylene carbonate (FEC), add methyl propionate and vinylene carbonate (VC), add polybenzyl methacrylate to obtain a mixed solution, and form a film at 60°C by solution casting method, and then hot press molding at 80°C.

[0068] Step 3: Battery Integration and Interface Optimization (1) Structural Design: The positive electrode material prepared in Example 1, the negative electrode material prepared in Example 2, and the solid electrolyte prepared in this example were used to manufacture the battery cell. References: In-situ electron microscopy reveals the lithium metal stripping mechanism (Science Advances (2025)) and Materials Today (2025) were used to describe the interface failure mechanism of lithium-rich manganese-based positive electrodes and solid electrolytes. The battery cell was constructed using CTP3.0 technology (for specific steps, refer to the Minutes of the CTP Technology Interpretation Meeting (July 2022)). The full-tab design reduces the number of module layers, achieving a volume utilization rate of 77% and a system energy density exceeding 620Wh / L.

[0069] (2) Interface engineering: Laser etching (wavelength 1064nm, power 20W) constructs a honeycomb 3D microstructure (pore size 10-30μm) on the surface of the positive and negative electrodes, increasing the interface contact area by 1.8 times and reducing the impedance to 28Ω·cm².

[0070] like Figure 5 As shown in Figure 2, replacing the solvent with a Li salt resulted in a higher mechanical toughness in SIC solid phase extraction. The resulting SPE is called SR-SPE ( Figure 5 A). The slidable cross-linked structure prevents stress concentration in the PEO chains during stretching ( Figure 5 In addition, the large strain induces the PEO chains to present a highly ordered orientation, leading to the formation of planar zigzag crystals of PEO ( Figure 5 C). However, SIC can improve the fracture energy but not the Young's modulus. Therefore, the following strategy was adopted to improve the Young's modulus: the crystallinity of PEO was controlled by changing the salt concentration ( Figure 5 D) and phase separation of CD in SR network ( Figure 5 Middle E).

[0071] Example 1 (core-shell composite positive electrode) comparative example: Comparative Example 1-1: Lithium-rich manganese-based single crystal cathode (LLMO) without ultra-high nickel coating. Preparation method: Only step (1) of Example 1 (single crystal LLMO) was performed, skipping ALD coating and gradient sintering. Performance defects: After 50 cycles at 4.6V, the capacity decayed to 68% (layered structure collapsed), and the interface impedance reached 142Ω·cm² (side reactions intensified). This demonstrates that stable high-voltage cycling is impossible without an ultra-high nickel coating.

[0072] Comparative Example 1-2: Physical mixing of LLMO and NCA (non-core-shell structure), preparation method: LLMO single crystal particles and commercial LiNi 0.92 Co 0.04 Al 0.04O2 powder was mechanically mixed (mass ratio 1:1). Performance deficiencies: compacted density was only 3.65 g / cm³, initial efficiency was 72.3%, and the shell peeled off after 100 cycles (SEM observation). This suggests that non-epitaxial growth leads to insufficient interfacial bonding.

[0073] Comparative Examples 1-3: Traditional one-step sintering (non-gradient process). Preparation method: Core-shell precursor directly sintered at 850°C for 14 hours (oxygen 5 L / min). Performance drawbacks: BET surface area > 5 m² / g, 300% increase in gas evolution rate during cycling, and significant risk of thermal runaway. This demonstrates the critical importance of gradient sintering for densification and safety.

[0074] In Example 1, through core-shell epitaxial growth + gradient sintering, the compaction density can be increased by 21%, the impedance can be reduced by 80%, and the 4.6V cycle life can be increased by 3 times.

[0075] Example 2 (Pre-lithiation silicon-carbon negative electrode) comparative example Comparative Example 2-1: SiOx / C composite anode without pre-lithiation agent. Preparation method: Only steps (1)-(2) of Example 2 (porous SiOx / C matrix + CVD carbon shell) were performed, omitting the Li5FeO4 ball milling. Performance drawbacks: initial efficiency was only 74.8% (serious lithium loss), and expansion ratio was >40% after 100 cycles (repeated SEI interface rupture). This demonstrates that pre-lithiation compensation is irreplaceable.

[0076] Comparative Example 2-2: SiOx negative electrode without graphitized carbon shell, preparation method: SiOx prepared by sol-gel method and then directly ball-milled and added with Li5FeO4 (no CVD step). Performance defect: conductivity <10 -3 S / cm, 1C rate capacity less than 50 mAh / g, and Li5FeO4 agglomeration (SEM). This demonstrates the key role of the graphitized carbon shell in conductivity and dispersion uniformity.

[0077] Comparative Example 2-3: Dry-mixed pre-lithiation agent (no ball milling). Preparation method: Li₅FeO₄ powder was simply dry-mixed with SiO₅ / C particles (without ball milling). Performance drawbacks: After five cycles, the capacity dropped 60% (due to partial failure of the pre-lithiation agent). EDS revealed uneven Li distribution (coefficient of variation >35%). This demonstrates that mechanical ball milling is the key process for achieving uniform dispersion.

[0078] In Example 2, the pre-lithiation + graphite carbon shell + ball milling process is used to achieve an initial efficiency greater than 86%, an expansion rate less than 15%, and a 200-cycle capacity retention rate of 82%.

[0079] Example 3 (Composite Solid-State Battery) Comparative Example Comparative Example 3-1: Pure PEO electrolyte (no LLZO filler). Preparation method: Film formation using only PEO / LiFSI (no LLZO or functional additives). Performance drawbacks: ionic conductivity of 0.01 mS / cm at 25°C, dendrite penetration after 100 hours of cycling at 60°C, and oxidation potential <4.0 V. This demonstrates the importance of inorganic fillers for ionic conductivity and high-voltage stability.

[0080] Comparative Example 3-2: Composite electrolyte without functional additives, preparation method: containing only the PEO-LLZO-LiFSI base system (without TMB / FEC / VC, etc.). Performance defects: -20℃ capacity retention rate <50%, interfacial impedance >200Ω·cm after 4.5V cycling 2 , thermal runaway at 180°C. This demonstrates the decisive influence of additives on wide temperature range and safety.

[0081] Comparative Example 3-3: Planar electrodes + traditional packaging (no CTP3.0 or laser etching). Fabrication method: Same electrolyte and electrode materials, but using planar stacking + module packaging. Performance drawbacks: Volume utilization is only 62%, energy density is 430Wh / L, and interface delamination occurs after 300 cycles at 1C. This demonstrates the value of integrating 3D microstructures with CTP3.0 in improving energy density and interface stability.

[0082] In Example 3, the energy density is increased by 44%, the temperature range is widened to -40~80℃, and the thermal runaway temperature is greater than 285℃ through the integration of composite electrolyte + CTP3.0.

[0083] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for preparing an all-solid-state battery, characterized in that: include: Preparation of positive electrode materials: single crystallization of lithium-rich manganese-based oxide, followed by coating with ultra-high nickel ternary positive electrode material to obtain a core-shell precursor, and mixing the core-shell precursor with a lithium source for gradient sintering; Preparation of negative electrode material: constructing a graphitized carbon shell on a porous silicon-carbon substrate by chemical vapor deposition to obtain a carbon-coated porous material, and mixing the carbon-coated porous material with a pre-lithiation agent; Preparation of composite solid electrolytes: Inorganic fillers, lithium salts and functional additives are introduced into the polymer matrix, and the solid electrolyte is prepared by solution casting or hot pressing process; Battery integration: preparing a battery core using the positive electrode material, the negative electrode material and the composite solid electrolyte, and performing battery integration.

2. The preparation method according to claim 1, characterized in that The process of preparing the positive electrode material includes: calcining the lithium-rich manganese-based oxide in an oxygen-containing atmosphere to obtain single crystal particles; epitaxially growing LiNi on the surface of the single crystal particles by atomic layer deposition. 0.92 Co 0.04 Al 0.04 The core-shell precursor is mixed with a lithium source and sintered at 730°C to 780°C for one stage, and then sintered at 820°C to 880°C for a second stage.

3. The preparation method according to claim 2, characterized in that The process for preparing the positive electrode material has at least one of features A1 to F1: Feature A1: During the preparation of the single crystal particles, the calcination temperature is controlled to be 920° C.-980° C., the calcination time is 10 h-15 h, and the calcination atmosphere is an oxygen-containing atmosphere; Feature B1: Growth of LiNi 0.92 Co 0.04 Al 0.04 The O2 shell process includes: using oxygen-containing gas as the reaction gas and using nickel source, cobalt source and aluminum source to perform element alternating deposition; Feature C1: Controlled formation of LiNi 0.92 Co 0.04 Al 0.04 The thickness of the O2 shell is 4nm-6nm; Feature D1: Growth of LiNi 0.92 Co 0.04 Al 0.04 During the O2 shell process, the reaction temperature is controlled at 200°C-300°C, the pulse time is 0.05s-0.20s, and the number of cycles is 40-60 times; Feature E1: Control the sintering time of one stage to be 4h-8h, the oxygen flow rate to be 1L / min-3L / min, and the heating rate to be 4℃ / min-6℃ / min; Feature F1: The sintering time of the second stage sintering is controlled to be 6h-10h, the oxygen flow rate is 4L / min-6L / min, and the heating rate is 1℃ / min-3℃ / min.

4. The preparation method according to claim 1, characterized in that The process of preparing the negative electrode material includes: using silicon source and carbon source as main raw materials, preparing a porous silicon-carbon matrix by a sol-gel method; placing the porous silicon-carbon matrix in a furnace body, introducing a mixed gas of acetylene and hydrogen, performing chemical vapor deposition to form a graphitized carbon layer, and obtaining a carbon-coated porous material; and ball-milling and mixing the carbon-coated porous material with the pre-lithiation agent.

5. The preparation method according to claim 4, characterized in that The process for preparing the negative electrode material has at least one of features A2 to G2: Feature A2: The silicon source is tetraethyl orthosilicate, the carbon source is sucrose, and the mass ratio of the silicon source to the carbon source is 1:(0.5-1.0); Feature B2: During the preparation of the porous silicon-carbon substrate, the carbonization temperature is controlled to be 850° C.-950° C. and the carbonization time is controlled to be 3 h-5 h under an inert atmosphere; Feature C2: The porous silicon-carbon matrix has a pore size distribution of 20 nm to 50 nm and a porosity of 60% to 70%; Feature D2: Control the thickness of the graphitized carbon layer to 3nm-5nm; Feature E2: During the formation of the graphitized carbon layer, the deposition temperature is controlled to be 780° C.-820° C., and the deposition time is controlled to be 10 min-15 min; Feature F2: During the formation of the graphitized carbon layer, the volume ratio of acetylene to hydrogen is controlled to be 1:(2-4); Feature G2: The pre-lithiation agent is Li5FeO4, and the mass ratio of the carbon-coated porous material to the pre-lithiation agent is 100:(8-12).

6. The preparation method according to claim 1, characterized in that Polyethylene oxide, inorganic fillers, lithium salts and functional additives are mixed and a solid electrolyte is prepared by solution casting or hot pressing.

7. The preparation method according to claim 6, characterized in that The process for preparing the solid-state electrolyte has at least one of features A3 to D3: Feature A3: The inorganic filler is a cubic phase Li 6.4 Al 0.2 La3Zr2O 12 , before adding, high-energy ball milling surface treatment is performed, the speed is controlled to be 400rpm-600rpm, the ball-to-material ratio is (15-25):1; the volume ratio of the inorganic filler to polyethylene oxide is (15-25):100; Feature B3: The lithium salt includes LiFSI and LiPF6, and the concentration of LiFSI is controlled to be 0.8M-1.2M, and the concentration of LiPF6 is controlled to be 0.1M-0.3M; Feature C3: The functional additives include trimethyl borate, fluoroethylene carbonate, methyl propionate, vinylene carbonate, and polybenzyl methacrylate, wherein the amount of trimethyl borate added is 1 wt%-3 wt%, the amount of fluoroethylene carbonate added is 2 wt%-4 wt%, the amount of methyl propionate added is 4 wt%-6 wt%, the amount of vinylene carbonate added is 0.5 wt%-1.5 wt%, and the amount of polybenzyl methacrylate added is 2 wt%-4 wt%; Feature D3: After mixing the raw materials and the solvent, the mixture is cast into a film at 50°C-70°C, and then hot-pressed at 70°C-90°C.

8. The preparation method according to claim 1, characterized in that Module-free battery integration technology is used for battery integration. After battery integration, 3D microstructures are constructed on the positive and negative electrode surfaces through laser etching technology.

9. The preparation method according to claim 8, characterized in that The wavelength of the laser etching is controlled to be 1060nm-1070nm, the power is 15W-25W, and the aperture of the 3D microstructure is 10μm-30μm.

10. An all-solid-state battery, characterized in that: It is prepared by the preparation method according to any one of claims 1 to 9.

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