Method for manufacturing low interfacial resistance solid state battery

Abstract

The application belongs to the technical field of solid-state battery manufacturing, and relates to a manufacturing method of a low-interface-resistance solid-state battery, comprising the following steps: 1) preparing a positive electrode material, a solid-state electrolyte material and a negative electrode material; 2) preparing composite positive electrode powder and solid-state electrolyte raw material based on the prepared positive electrode material and solid-state electrolyte material respectively; 3) forming a solid-state battery positive electrode and a solid-state battery electrolyte by using an indirect 3D printing process respectively; 4) assembling the formed solid-state battery positive electrode and solid-state battery electrolyte to form an assembly; and 5) introducing the negative electrode material to the assembly to form a solid-state battery. The application provides a manufacturing method of a low-interface-resistance solid-state battery which can improve interface wettability, can improve ion conductivity and can realize batch manufacturing.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of solid-state battery manufacturing, and relates to a solid-state battery manufacturing method, in particular to a low-interface-resistance solid-state battery manufacturing method. BACKGROUND

[0002] With the increasing demand for high-performance lithium ion batteries, all-solid-state batteries with the advantages of high energy density, good safety, long cycle life, wide working temperature range and the like have gradually become a research hotspot in the field of batteries in recent years. However, the electrode material and solid-state electrolyte material used in the all-solid-state battery are both solid, and the solid-state electrolyte and the electrode are in solid-solid rigid contact, which leads to excessive interface impedance and adversely affects the use performance.

[0003] At present, increasing the interface contact area to reduce the interface impedance is a relatively quick method. Patent CN111092254B adopts a roll-pressed composite positive electrode to increase the interface contact area, but the composite positive electrode needs to adopt a gradient coating process, which not only takes a long time but also easily causes deformation and cracking of the composite positive electrode. Patent CN110931848A adopts the method of adding acid liquid to the surface of the solid-state electrolyte to form a porous structure to increase the interface contact area, which can improve the interface compatibility, but the direction and depth of the acid liquid erosion of the solid-state electrolyte are uncertain, resulting in poor batch production stability, and the acid liquid has low efficiency, high pollution and high cost in forming the pore structure. In general, the process of reducing the interface impedance by increasing the interface contact area has the following problems: ① poor structure controllability; ② low efficiency and high cost; and ③ pollution problem. SUMMARY

[0004] In order to solve the above technical problems in the background art, the application provides a low-interface-resistance solid-state battery manufacturing method which can improve the interface wettability, increase the ion conductivity and realize batch manufacturing.

[0005] In order to achieve the above purpose, the application adopts the following technical scheme:

[0006] A low-interface-resistance solid-state battery manufacturing method, characterized in that the low-interface-resistance solid-state battery manufacturing method comprises the following steps:

[0007] 1) preparing a positive electrode material, a solid-state electrolyte material and a negative electrode material;

[0008] 2) preparing a composite positive electrode powder and a solid-state electrolyte raw material based on the positive electrode material and the solid-state electrolyte material prepared in step 1);

[0009] 3) forming a solid-state battery positive electrode and a solid-state battery electrolyte by adopting an indirect 3D printing process;

[0010] 4) Assembling the solid-state battery anode and the solid-state battery electrolyte obtained in step 3) to form an assembly;

[0011] 5) Introducing the negative electrode material to the assembly to form a solid-state battery.

[0012] The step 4) is specifically:

[0013] 4.1) Taking the solid-state battery anode and the solid-state battery electrolyte obtained in step 3);

[0014] 4.2) Coating the anode coating slurry on the contact surface of the solid-state battery anode and the solid-state battery electrolyte;

[0015] 4.3) Assembling the solid-state battery anode and the solid-state battery electrolyte and then sintering to obtain an assembly.

[0016] The anode coating slurry is prepared by adding the composite anode powder to the N-methyl pyrrolidone containing polyvinylidene fluoride, wherein the volume fraction of the composite anode powder is 70% to 90%.

[0017] The sintering temperature in step 4.3) is 80°C to 300°C.

[0018] The composite anode powder includes 65% to 85% of anode material, 10% to 30% of solid-state electrolyte material, and 1% to 5% of conductive agent by weight.

[0019] The anode material is one or a mixture of several of lithium iron phosphate, lithium manganese oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium manganese phosphate, and lithium manganese iron phosphate;

[0020] The solid-state electrolyte material is an oxide solid-state electrolyte and / or a sulfide electrolyte; the oxide solid-state electrolyte is a NASICON-type oxide solid-state electrolyte, a perovskite-type oxide solid-state electrolyte, an inverse perovskite-type oxide solid-state electrolyte, a garnet-type oxide solid-state electrolyte, or a LISICON-type oxide solid-state electrolyte; the sulfide electrolyte is a glass electrolyte, a glass-ceramic electrolyte, or a crystalline electrolyte;

[0021] The conductive agent is one or a combination of several of superp, acetylene black, ketjen black, carbon nanotube, and graphene.

[0022] The step 3) is specifically:

[0023] 3.1) Using an indirect 3D printing process to form the composite anode powder and the solid-state electrolyte raw material to the solid-state battery anode embryo and the solid-state electrolyte embryo, respectively;

[0024] 3.2) forming a solid-state battery cathode and a solid-state battery electrolyte after debinding and sintering.

[0025] The indirect 3D printing process is a binder jet printing process, a fused deposition printing process, a selective laser sintering printing process or a light curing printing process; the debinding and sintering temperature of the solid-state battery cathode precursor is 200-1000℃, and the sintering time is 2-24h; the debinding and sintering temperature of the solid-state electrolyte precursor is 500-1250℃, and the sintering time is 5-20h.

[0026] The step 5) is specifically: heating the negative electrode material to 180-400℃, and pressing the molten negative electrode material on the assembly to form a solid-state battery with a solid-state battery cathode-solid-state battery electrolyte-solid-state battery negative electrode structure.

[0027] The negative electrode material is modified lithium, lithium and its alloy.

[0028] The advantages of the present application are:

[0029] The present application provides a method for manufacturing a low-interface-resistance solid-state battery, which comprises the following steps: 1) preparing a cathode material, a solid-state electrolyte material and a negative electrode material; 2) preparing a composite cathode powder and a solid-state electrolyte raw material based on the prepared cathode material and solid-state electrolyte material, respectively; 3) forming a solid-state battery cathode and a solid-state battery electrolyte by using an indirect 3D printing process; 4) assembling the formed solid-state battery cathode and solid-state battery electrolyte to form an assembly; and 5) introducing the negative electrode material to the assembly to form a solid-state battery. By using the technical solution of the present application, the following beneficial effects can be achieved: designing convex-concave features at the interface between the electrode and the solid-state electrolyte to increase the interface contact area; coating a cathode slurry at the interface between the cathode and the solid-state electrolyte to improve the interface wettability; forming the cathode and the solid-state electrolyte by using an indirect 3D printing process to realize batch manufacturing; and densifying the cathode and the electrolyte by sintering to improve the ion conductivity. The guardrail structure designed at the interface is more conducive to the coating of the cathode slurry, and waste of raw materials is avoided. DETAILED DESCRIPTION

[0030] The present application uses a 3D printing process to form a cathode and a solid-state electrolyte with the above structure, and the contact surface of the cathode and the solid-state electrolyte is treated, and finally a solid-state battery is manufactured. The method for manufacturing a low-interface-resistance solid-state battery provided by the present application specifically comprises the following contents:

[0031] 1) preparing a cathode material, a solid-state electrolyte material and a negative electrode material;

[0032] The cathode material is one or a mixture of several of lithium iron phosphate, lithium manganate, lithium nickel manganate, lithium nickel cobalt manganate, lithium manganese phosphate and lithium manganese iron phosphate;

[0033] The solid-state electrolyte material is an oxide solid-state electrolyte and / or a sulfide electrolyte; the oxide solid-state electrolyte is a NASICON type oxide solid-state electrolyte, a perovskite type oxide solid-state electrolyte, an inverse perovskite type oxide solid-state electrolyte, a garnet type oxide solid-state electrolyte or a LISICON type oxide solid-state electrolyte; the sulfide electrolyte is a glass electrolyte, a glass-ceramic electrolyte or a crystalline electrolyte; the solid-state electrolyte material is prepared by weighing inorganic solid-state electrolyte powder, and then combining ball milling, drying, pre-sintering and calcining processes to obtain solid-state electrolyte raw materials.

[0034] The negative electrode material is modified lithium, lithium and its alloy.

[0035] 2) Based on the positive electrode material and the solid-state electrolyte material prepared in step 1), composite positive electrode powder and solid-state electrolyte raw materials are respectively prepared;

[0036] 3) The indirect 3D printing process is used to respectively form the solid-state battery positive electrode and the solid-state battery electrolyte, and the specific implementation manner is:

[0037] 3.1) The composite positive electrode powder and the solid-state electrolyte raw material are respectively formed by the indirect 3D printing process to obtain the solid-state battery positive electrode blank and the solid-state electrolyte blank; wherein the indirect 3D printing process is a binder jet printing process, a fused deposition printing process, a selective laser sintering printing process or a light curing printing process;

[0038] 3.2) After debinding and sintering, the solid-state battery positive electrode and the solid-state battery electrolyte are formed, the debinding and sintering temperature of the solid-state battery positive electrode blank is 200-1000℃, and the sintering time is 2-24h; the debinding and sintering temperature of the solid-state electrolyte blank is 500-1250℃, and the sintering time is 5-20h.

[0039] 4) The solid-state battery positive electrode and the solid-state battery electrolyte formed in step 3) are assembled to form an assembly, and the specific implementation manner is:

[0040] 4.1) The solid-state battery positive electrode and the solid-state battery electrolyte formed in step 3) are taken;

[0041] 4.2) The positive electrode coating slurry is coated on the contact surface of the solid-state battery positive electrode and the solid-state battery electrolyte;

[0042] 4.3) After assembling the solid-state battery positive electrode and the solid-state battery electrolyte, low-temperature sintering is carried out, and the sintering temperature is 80-300℃, to obtain the assembly.

[0043] The positive electrode coating slurry is prepared by adding a composite positive electrode powder into N-methyl pyrrolidone containing polyvinylidene fluoride, and the volume fraction of the composite positive electrode powder in the slurry is 70% to 90%. The composite positive electrode powder includes 65% to 85% of a positive electrode material, 10% to 30% of a solid electrolyte material, and 1% to 5% of a conductive agent by weight. The conductive agent is one or a combination of super p, acetylene black, ketjen black, carbon nanotubes, and graphene.

[0044] 5) The negative electrode material is heated to 180°C to 400°C, and after the negative electrode material is melted, it is flattened on the assembly to form a solid-state battery of the positive electrode-solid-state battery electrolyte-solid-state battery negative electrode structure.

[0045] At the same time, the solid-state battery prepared based on the above method has a thickness of 0.8 to 1.8 mm and an electrode thickness of 120 to 300 μm. Preferably, uniform and complementary features are designed at the interface between the electrode and the solid-state electrolyte, and the features should satisfy the following size relationship: the distance between the protrusions and the protrusions, and the distance between the depressions and the depressions is 0.1 to 1 mm, and the height of the protrusions or the depth of the depressions is 30 to 100 μm.

[0046] Example 1 Preparation of a garnet-type solid-state electrolyte battery

[0047] (1) Solid-state battery design

[0048] The solid-state electrolyte has a thickness of 1.3 mm and an electrode thickness of 200 μm. The distance between the protrusions and the protrusions, and the distance between the depressions and the depressions is 0.5 mm, and the height of the protrusions or the depth of the depressions is 100 μm.

[0049] (2) Material selection and processing

[0050] Selection and processing of solid-state electrolyte: according to Li 6.75 La3Zr 1.75 Ta 0.25 O 12 LiOH·H2O, La2O3 (900°C high temperature treatment for 12 h before weighing), ZrO2 and Ta2O5 are weighed according to the stoichiometric ratio. After wet grinding, dry and crush, pre-sinter, then sinter at 1150°C for 12 h. Wet grinding and drying, then sieving to obtain calcined LLZTO powder, and mixing the LLZTO powder with a binder to prepare the solid-state electrolyte raw material for 3D printing.

[0051] Selection and treatment of positive electrode material: NCM811, LLZTO, carbon nanotubes are mixed uniformly according to the mass ratio of 80:15:5, and then mixed with the binder to prepare the composite positive electrode powder for 3D printing. The composite positive electrode powder formed by NCM811, LLZTO and carbon nanotubes is added into NMP (N-methyl pyrrolidone) containing PVDF to prepare the positive electrode coating slurry.

[0052] Selection of negative electrode material: lithium metal is selected as the negative electrode material.

[0053] (3) Positive electrode and electrolyte forming

[0054] The light-cured 3D printing process is used for forming, the debinding temperature is 420°C, the solid electrolyte sintering temperature is 1170°C, and the sintering time is 10h. The composite positive electrode sintering temperature is 850°C, and the sintering time is 15h.

[0055] (4) Battery assembly and negative electrode introduction

[0056] The positive electrode coating slurry prepared by coating the contact surface of the positive electrode and the solid electrolyte is then assembled and sintered at a low temperature, and the sintering temperature is 300°C. The lithium metal is heated to 180°C to melt and is pressed on the other side of the solid electrolyte to assemble the solid-state battery.

[0057] Preparation of sulfide solid electrolyte battery in Example 2

[0058] (1) Solid-state battery design

[0059] The thickness of the solid electrolyte is 1mm, and the thickness of the electrode is 150μm. The distance between the protrusions and the protrusions, and the distance between the depressions and the depressions is 0.8mm, and the height of the protrusions or the depth of the depressions is 80μm.

[0060] (2) Material selection and treatment

[0061] Selection and treatment of solid electrolyte: Li2S, GeS2, P2S5 are weighed according to the molar ratio of 5:1:1, P2S5 should be excessive, and after ball milling in an argon-filled ball mill jar, the solid electrolyte raw material for 3D printing is prepared by mixing with the binder.

[0062] Selection and treatment of positive electrode material: In the high-purity argon glove box, lithium nickel cobalt manganese oxide, the above sulfide solid dielectric and superp are weighed according to the mass ratio of 80:16:4, and then mixed uniformly in the ball mill jar under the protection of the atmosphere, and then mixed with the binder to prepare the composite positive electrode powder for 3D printing. The composite positive electrode powder is added into NMP (N-methyl pyrrolidone) containing PVDF to prepare the positive electrode coating slurry.

[0063] Selection of negative material: modified lithium is selected as the negative material.

[0064] (3) Shaping of positive electrode and electrolyte

[0065] Binder spray forming is used, the debinding temperature after shaping is 380°C, the sintering temperature of solid electrolyte is 600°C, and the sintering time is 12h. The sintering temperature of the composite positive electrode is 800°C, and the sintering time is 18h.

[0066] (4) Assembly of solid-state battery

[0067] Assembly of positive electrode and solid electrolyte: the contact surface of the positive electrode and the solid electrolyte is coated with the positive electrode slurry prepared in the second step, followed by assembly, and then low-temperature sintering is performed at a sintering temperature of 280°C. The modified lithium is heated to 220°C and flattened on the other side of the solid electrolyte, and the solid-state battery is assembled.

Claims

1. A method for manufacturing a low-interface-resistance solid-state battery, characterized in that: The method for manufacturing the low interfacial resistance solid-state battery includes the following steps: 1) Prepare positive electrode materials, solid electrolyte materials, and negative electrode materials; 2) Based on the cathode material and solid electrolyte material prepared in step 1), composite cathode powder and solid electrolyte raw material are prepared respectively; 3) The solid-state battery cathode and solid-state battery electrolyte are formed separately using indirect 3D printing process, and uniform and complementary convex and concave features are designed at the interface between the solid-state battery cathode and solid-state electrolyte. 4) Assemble the solid-state battery positive electrode and solid-state battery electrolyte obtained in step 3) to form an assembly; specifically: 4.1) Take the solid-state battery positive electrode and solid-state battery electrolyte obtained in step 3); 4.2) Coat the contact surface between the positive electrode and the electrolyte of the solid-state battery with a positive electrode coating slurry; 4.3) After assembling the solid-state battery positive electrode and solid-state battery electrolyte, they are sintered to obtain the assembly; 5) Introduce the negative electrode material onto the assembly to form a solid-state battery; The positive electrode coating slurry is prepared by adding composite positive electrode powder to N-methylpyrrolidone containing polyvinylidene fluoride, wherein the volume fraction of the composite positive electrode powder is 70%~90%. The composite cathode powder comprises 65% to 85% cathode material, 10% to 30% solid electrolyte material, and 1% to 5% conductive agent by weight.

2. The method for manufacturing a low interfacial resistance solid-state battery according to claim 1, characterized in that: The sintering temperature in step 4.3) is 80℃~300℃.

3. The method for manufacturing a low interfacial resistance solid-state battery according to claim 1, characterized in that: The cathode material is one or a mixture of several of lithium iron phosphate, lithium manganese oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium manganese phosphate, and lithium manganese iron phosphate. The solid electrolyte material is an oxide solid electrolyte and / or a sulfide electrolyte; the oxide solid electrolyte is a NASICON type oxide solid electrolyte, a perovskite type oxide solid electrolyte, an anti-perovskite type oxide solid electrolyte, a garnet type oxide solid electrolyte, or a LISICON type oxide solid electrolyte; the sulfide electrolyte is a glass electrolyte, a glass ceramic electrolyte, or a crystalline electrolyte. The conductive agent is one or a combination of several of the following: super p, acetylene black, Ketjen black, carbon nanotubes, and graphene.

4. The method for manufacturing a low interfacial resistance solid-state battery according to any one of claims 1-3, characterized in that: Step 3) specifically involves: 3.1) The composite cathode powder and solid electrolyte raw material are formed into solid battery cathode preforms and solid electrolyte preforms respectively using an indirect 3D printing process; 3.2) After degreasing and sintering, a solid-state battery positive electrode and a solid-state battery electrolyte are formed.

5. The method for manufacturing a low interfacial resistance solid-state battery according to claim 4, characterized in that: The indirect 3D printing process is a binder jet printing process, a fused deposition modeling process, a selective laser sintering printing process, or a photopolymerization printing process. The degreasing and sintering temperature of the solid-state battery cathode preform is 200~1000℃, and the sintering time is 2~24h; the degreasing and sintering temperature of the solid-state electrolyte preform is 500~1250℃, and the sintering time is 5~20h.

6. The method for manufacturing a low interfacial resistance solid-state battery according to claim 5, characterized in that: Step 5) specifically involves heating the negative electrode material to 180℃-400℃, and after the negative electrode material melts, pressing it flat onto the assembly to form a solid-state battery with a structure of solid-state battery positive electrode-solid-state battery electrolyte-solid-state battery negative electrode.

7. The method for manufacturing a low interfacial resistance solid-state battery according to claim 6, characterized in that: The negative electrode material is any one of modified lithium, lithium, and lithium alloys.