Preparation process of oxide solid-state battery and solid-state battery

Abstract

The present application relates to the technical field of solid-state battery, and relates to a preparation process of oxide solid-state battery and the solid-state battery.The preparation process comprises the following steps: 1) preparing anode material, electrolyte material, cathode material and pore-forming material for the solid-state battery; 2) preparing the anode material, electrolyte material and pore-forming material into nanoscale raw material powder respectively; 3) printing the nanoscale raw material powder layer by layer respectively to form a composite structure of anode layer-anode and electrolyte transition layer-electrolyte layer; 4) performing hot-press sintering on the composite structure of anode layer-anode and electrolyte transition layer-electrolyte layer to form a sintered body; and 5) introducing the cathode material to the electrolyte layer of the sintered body to form the oxide solid-state battery.The present application provides a preparation process of oxide solid-state battery and the solid-state battery, which can effectively avoid the problems of interface contact, volume expansion and lithium dendrite growth of the oxide solid-state battery.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solid-state batteries, and relates to a preparation process of a solid-state battery and a solid-state battery, in particular to a preparation process of an oxide solid-state battery and a solid-state battery. BACKGROUND

[0002] A solid-state battery is a new type of battery with both electrodes and electrolytes being solid. Due to its high energy density, good safety, long cycle life, fast charging speed, large miniaturization space and a series of advantages, it is considered as an important development direction of future batteries. Among them, the oxide solid-state battery is particularly attractive due to its balanced process difficulty and energy density.

[0003] At present, the production of the oxide solid-state battery is mainly completed by respectively producing a solid-state electrode and a solid-state electrolyte, and then assembling the battery. Each step is realized by using a traditional process. Due to the deficiencies of the traditional process in precision control, material distribution and structure realization, the structure design innovation of the solid-state battery is delayed at the present stage, the potential advantages are insufficiently released, the production efficiency is low, and the manufacturing cost is high, which hinders the solution process of the problems such as poor interface contact, volume expansion and lithium dendrite growth of the oxide solid-state battery, and restricts the application and development of the oxide solid-state battery. SUMMARY

[0004] In order to solve the above technical problems in the background art, the present application provides a preparation process of an oxide solid-state battery and a solid-state battery which can effectively avoid the problems such as interface contact, volume expansion and lithium dendrite growth of the oxide solid-state battery.

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

[0006] A preparation process of an oxide solid-state battery, characterized in that the preparation process of the oxide solid-state battery comprises the following steps:

[0007] 1) preparing materials for the solid-state battery; the materials for the solid-state battery include a positive electrode material, an electrolyte material, a negative electrode material and a pore-forming material;

[0008] 2) preparing the positive electrode material, the electrolyte material and the pore-forming material into nanoscale raw material powders respectively;

[0009] 3) layer by layer printing the nanoscale raw material powders prepared in step 2) respectively to form a composite structure of a positive electrode layer-positive electrode and electrolyte transition layer-electrolyte layer;

[0010] 4) heat pressing and sintering the composite structure of the positive electrode layer-positive electrode and electrolyte transition layer-electrolyte layer prepared in step 3) to form a sintered body;

[0011] 5) introducing the negative electrode material to the electrolyte layer of the sintered body prepared in step 4) to form the oxide solid-state battery.

[0012] The step 3) is specifically:

[0013] 3.1) spraying the nanoscale positive electrode material on the current collector as the substrate according to the material spray forming process to form the positive electrode layer;

[0014] 3.2) spraying the nanoscale positive electrode material and the nanoscale electrolyte material on the positive electrode layer as the substrate according to the material spray forming process to form the positive electrode and electrolyte transition layer on the positive electrode layer;

[0015] 3.3) spraying the nanoscale electrolyte material and the nanoscale pore-forming material on the positive electrode and electrolyte transition layer as the substrate according to the material spray forming process to finally form the composite structure of the positive electrode layer-positive electrode and electrolyte transition layer-electrolyte layer.

[0016] The positive electrode and electrolyte transition layer includes a plurality of transition sub-layers, and the use amount of the nanoscale positive electrode material in each transition sub-layer decreases in turn along the direction from the positive electrode layer to the positive electrode and electrolyte transition layer, the use amount of the nanoscale electrolyte material in each transition sub-layer increases in turn, and any material of each transition sub-layer and the same material of the adjacent transition sub-layer are connected to each other.

[0017] The step 3.3) is specifically:

[0018] 3.3.1) spraying the nanoscale electrolyte material on the positive electrode and electrolyte transition layer as the substrate according to the material spray forming process to form the basic electrolyte sub-layer;

[0019] 3.3.2) spraying the nanoscale electrolyte material and the nanoscale pore-forming material on the basic electrolyte sub-layer as the substrate according to the material spray forming process by using different spray heads to form the electrolyte sub-layer containing the pore-forming material, and the negative electrode end interface of the electrolyte sub-layer containing the pore-forming material is a rough surface with Ra of 5-20;

[0020] The basic electrolyte sub-layer and the electrolyte sub-layer containing the pore-forming material jointly constitute the electrolyte layer; and the positive electrode layer, the positive electrode and electrolyte transition layer, and the electrolyte layer finally form the composite structure of the positive electrode layer-positive electrode and electrolyte transition layer-electrolyte layer.

[0021] The step 4) is specifically:

[0022] 4.1) designing the hot-press sintering temperature according to the melting point of the positive electrode material, the melting point of the electrolyte material, and the melting point of the pore-forming material; the hot-press sintering temperature is T, the melting point of the positive electrode material is T正 The melting point of the electrolyte material is T 电 The melting point of the pore-forming material is T 造 ; T 正 >T>T 造 ; T 电 >T>T 造 ;

[0023] 4.2) Hot-press sintering the composite structure of the anode layer-anode and electrolyte transition layer-electrolyte layer prepared in step 3) at a hot-press sintering temperature T, to remove the pore-forming material in the electrolyte layer and form micropores in the electrolyte layer, to obtain a densified sintered body.

[0024] The above step 5) is specifically:

[0025] 5.1) Preheating the sintered body, and the preheating temperature is 150-180℃;

[0026] 5.2) Introducing the negative electrode material onto the electrolyte layer of the sintered body by using the lithium melting method, with the sintered body as the substrate, to finally form an oxide solid-state battery.

[0027] The above anode material is lithium manganate, lithium cobaltate, lithium iron phosphate, lithium nickel cobalt aluminum acid or lithium nickel cobalt manganese acid; the electrolyte material is Li 6.4 Ga 0.2 La3Zr2O 12 , Li 6.55 Ga 0.15 La3Zr2O 12 , Li 6.4 La3Zr 1.4 Ta 0.6 O 12 , Li 6.6 La3Zr 1.8 Mo 0.2 O 12 , Li 6.4 La3Zr 1.7 W 0.3 O 12 or Li7La3Zr 1.75 Ta 0.25 Ga 0.2 O 12 ; the pore-forming material is paraffin powder, PE, PP or POM; and the negative electrode material is metallic lithium or lithium alloy.

[0028] An oxide solid-state battery prepared based on the preparation process of the oxide solid-state battery as described above, the oxide solid-state battery comprising a negative electrode layer, an electrolyte layer, a positive electrode and electrolyte transition layer, and a positive electrode layer; the negative electrode layer, the electrolyte layer, and the positive electrode and electrolyte transition layer are sequentially formed on the positive electrode layer from bottom to top; preferably, the electrolyte layer contains a microporous structure; the micropores are multiple, and the multiple micropores are uniformly filled in the electrolyte layer close to the negative electrode end; preferably, the micropores are in the shape of water droplets or pyramids as a whole; the sharp corners of the micropores are directed towards the negative electrode layer; preferably, the contact surface between the electrolyte layer and the negative electrode layer is a non-smooth surface; preferably, the roughness Ra of the contact surface between the electrolyte layer and the negative electrode layer is 5-20.

[0029] The advantages of the present application are:

[0030] The present application provides a preparation process of an oxide solid-state battery and a solid-state battery, comprising 1) preparing materials for the solid-state battery; the materials for the solid-state battery comprise positive electrode materials, electrolyte materials, negative electrode materials, and pore-forming materials; 2) preparing the positive electrode materials, the electrolyte materials, and the pore-forming materials into nanoscale raw material powders respectively; 3) layer-by-layer printing the nanoscale raw material powders prepared in step 2) respectively to form a composite structure of a positive electrode layer-positive electrode and electrolyte transition layer-electrolyte layer; 4) heat pressing and sintering the composite structure of the positive electrode layer-positive electrode and electrolyte transition layer-electrolyte layer prepared in step 3) to form a sintered body; 5) introducing the negative electrode materials to the electrolyte layer of the sintered body prepared in step 4) to form an oxide solid-state battery. The present application designs a positive electrode and electrolyte transition layer between the positive electrode layer and the electrolyte layer, increases the contact area of the positive electrode layer and the electrolyte layer, and solves the "solid-solid interface" problem between the positive electrode layer and the electrolyte layer. At the same time, the positive electrode layer and electrolyte layer printing body is treated by heat pressing and co-sintering, which realizes the densification of the electrolyte layer and further improves the "solid-solid interface" between the positive electrode layer and the electrolyte layer. In addition, the positive electrode layer and the electrolyte layer are processed using a material jetting device, which accurately controls the size accuracy and material distribution of the positive electrode layer and the electrolyte layer, and can realize complex structures; a porous structure defect is designed in the electrolyte layer close to the negative electrode layer, which utilizes the accommodation and limitation of the defect to lithium dendrites to inhibit the penetration of disordered growing lithium dendrites into the battery to cause short circuit; the interface between the negative electrode layer and the electrolyte layer is designed to increase the contact area of the negative electrode layer and the electrolyte layer and improve the energy efficiency of the battery. The present application introduces the negative electrode layer under negative pressure by the lithium melting method, and preheats the sintered body of the positive electrode layer and the electrolyte layer to promote the contact effect between the electrolyte layer and the negative electrode layer. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 is a cross-sectional structure schematic diagram of the solid-state battery prepared based on the preparation process provided by the present application;

[0032] Figure 2is a schematic view of electrolyte layer cross-sectional area division according to nozzle resolution when forming the electrolyte layer;

[0033] Figure 3 is a schematic view of electrolyte layer micro-hole shape;

[0034] wherein:

[0035] 1 - negative electrode layer; 2 - electrolyte layer; 3 - positive electrode and electrolyte transition layer; 4 - positive electrode layer; a - micro-hole; b - electrolyte. DETAILED DESCRIPTION

[0036] The application provides a preparation process of an oxide solid-state battery, which comprises the following steps:

[0037] 1) preparing materials for the solid-state battery; the materials for the solid-state battery include positive electrode materials, electrolyte materials, negative electrode materials and pore-forming materials; wherein the positive electrode materials can be lithium manganate, lithium cobaltate, lithium iron phosphate, lithium nickel cobalt aluminum acid or nickel cobalt manganese acid; the electrolyte materials can be Li 6.4 Ga 0.2 La3Zr2O 12 、Li 6.55 Ga 0.15 La3Zr2O 12 、Li 6.4 La3Zr 1.4 Ta 0.6 O 12 、Li 6.6 La3Zr 1.8 Mo 0.2 O 12 、Li 6.4 La3Zr 1.7 W 0.3 O 12 、Li7La3Zr 1.75 Ta 0.25 Ga 0.2 O 12 and other garnet-type oxide solid-state electrolytes. The pore-forming materials can be paraffin powder, polyethylene PE, polypropylene PP or polyoxymethylene POM; and the negative electrode materials are metal lithium or lithium alloy.

[0038] 2) The cathode material, electrolyte material, and pore-forming material are prepared into nanoscale raw material powders. The specific preparation process is as follows: the cathode material and electrolyte material are added separately into a ball mill, and high-hardness grinding balls are used to crush them in the ball mill, so that the cathode material and electrolyte material become nanoscale raw materials that can be used by the material spraying forming equipment. After screening, they are loaded into the forming equipment. At the same time, the pore-forming material is also nanoscaled so that it can be used by the material spraying forming equipment. The pore-forming material is a material with a certain supporting strength and can completely eliminate any pores left at high temperatures.

[0039] 3) The nanoscale raw material powder prepared in step 2) is printed layer by layer to form a composite structure of positive electrode layer-positive electrode and electrolyte transition layer-electrolyte layer, specifically:

[0040] 3.1) Using the current collector as a substrate, nanoscale positive electrode material is sprayed onto the current collector according to the material spraying forming process to form positive electrode layer 4;

[0041] 3.2) Using the positive electrode layer 4 as a substrate, nanoscale positive electrode material and nanoscale electrolyte material are sprayed onto the positive electrode layer 4 layer by layer according to the material spraying forming process, forming a positive electrode and electrolyte transition layer 3 on the positive electrode layer 4; the positive electrode and electrolyte transition layer 3 includes multiple transition layers. Along the direction from the positive electrode layer 4 to the positive electrode and electrolyte transition layer 3, the amount of nanoscale positive electrode material used in each transition layer decreases sequentially, and the amount of nanoscale electrolyte material used in each transition layer increases sequentially. Among them, a certain material in each transition layer is connected to the same material in the adjacent transition layer.

[0042] 3.3) Using the positive electrode and electrolyte transition layer 3 as a substrate, nanoscale electrolyte material and nanoscale pore-forming material are sprayed onto the positive electrode and electrolyte transition layer 3 as needed using a material spraying forming process, ultimately forming a composite structure of positive electrode layer-positive electrode and electrolyte transition layer-electrolyte layer, specifically:

[0043] 3.3.1) Using the positive electrode and electrolyte transition layer 3 as a substrate, nanoscale electrolyte material is sprayed onto the positive electrode and electrolyte transition layer 3 according to the material spraying forming process to form a basic electrolyte layer;

[0044] 3.3.2) Using the basic electrolyte layer as a substrate, and following a material spraying process, different nozzles are used to spray nanoscale electrolyte material and nanoscale pore-forming material layer by layer onto the basic electrolyte layer, forming an electrolyte layer containing pore-forming material; as shown in... Figure 2 For example, the process is explained as follows: In Figure 2The small squares represent nozzle resolution, and the large square represents the current printing layer cross-sectional area. Assuming two nozzles are used, the two nozzles respectively spray nanoscale electrolyte materials and nanoscale pore-forming materials, and the two nozzles are arranged in parallel and work simultaneously. Figure 2 For example, from left to right, the two nozzles work for the first time, respectively in the first row and the second column (i.e., the two nozzles are respectively placed in the first small square and the second small square in the first row), and after spraying the corresponding nanomaterials in the two small squares, the two nozzles are translated so that the two nozzles are respectively in the third column and the fourth column in the first row (i.e., the two nozzles are respectively placed in the third small square and the fourth small square in the first row), and the spraying work is carried out in the third small square and the fourth small square. This is the second time, and the step is repeated until the first row is printed. Continue to repeat the above steps until the printing of the second row, the printing of the third row, and so on, and finally complete the printing of the entire large square. This process is the formation of the first printing layer. Continue to repeat the above content to complete the formation of the second printing layer, the formation of the third printing layer, and so on, until the electrolyte layer containing the pore-forming material is formed. Since the spraying process is completed sequentially, the three-dimensional structure of the electrolyte layer containing the pore-forming material finally formed is as shown in Figure 3 .

[0045] The base electrolyte layer and the electrolyte layer containing the pore-forming material form the electrolyte layer 2 as a whole; the positive electrode layer 4, the positive electrode and electrolyte transition layer 3, and the electrolyte layer 2 finally form the composite structure of positive electrode layer-positive electrode and electrolyte transition layer-electrolyte layer.

[0046] It should be noted that when the above spraying (layer-by-layer printing) is carried out according to the material spraying forming process, the thickness of each functional layer (the positive electrode layer 4, the positive electrode and negative electrode transition layer 3, and the electrolyte layer 2) is adjusted according to the thickness of each functional layer of the oxide solid-state battery to ensure that the number of printed layers of each functional layer of the oxide solid-state battery is an integer, so as to avoid the case that a certain printing layer crosses different functional layers, thereby affecting the size accuracy of each functional layer of the battery. The distribution rule of the material used in the positive electrode and negative electrode transition layer 3 is that the material is evenly distributed by the change space of 0-100% according to the multiple relationship between the thickness of the positive electrode and negative electrode transition layer 3 and the thickness of the transition layer. The proportion of different materials in the layer is realized by controlling the proportion of each material in the total number of layer cross-sectional area division according to the nozzle resolution. When the materials are distributed, each material is discrete and uniform, and the same material is connected between layers; the printing at the micropore a on the electrolyte layer 2 is filled with the pore-forming material.

[0047] 4) Heat pressing and sintering the composite structure of the positive electrode layer-positive electrode and electrolyte transition layer-electrolyte layer prepared in step 3) to form a sintered body, specifically:

[0048] 4.1) Designing the hot-press sintering temperature according to the melting point of the positive electrode material, the melting point of the electrolyte material and the melting point of the pore-forming material; the hot-press sintering temperature is T, the melting point of the positive electrode material is T 正 , the melting point of the electrolyte material is T 电 , and the melting point of the pore-forming material is T 造 ; T 正 > T > T 造 ; T 电 > T > T 造 ;

[0049] 4.2) Hot-press sintering the composite structure of the positive electrode layer-positive electrode and electrolyte transition layer-electrolyte layer prepared in step 3) using the hot-press sintering temperature T, since the hot-press sintering temperature T is higher than the melting point T 造 of the pore-forming material, the pore-forming material in the electrolyte layer 2 can be removed in the process of hot-press sintering, at the same time, the micropores a are formed in the electrolyte layer 2, and a sintered body is formed, which is completely densified except for the micropores a, and the roughness Ra of the contact surface between the electrolyte layer 2 and the negative electrode layer 1 on the sintered body is 5-20.

[0050] 5) Introducing the negative electrode material to the electrolyte layer of the sintered body prepared in step 4) to form an oxide solid-state battery, and the introduction mode can be extrusion forming, liquid injection and coating, etc. For example, the present application adopts lithium melting method, which is beneficial to the filling and combination of the rough interface. The specific way of the introduction operation is:

[0051] 5.1) Preheating the sintered body, and the preheating temperature is 150-180℃;

[0052] 5.2) Introducing the negative electrode material to the electrolyte layer of the sintered body using the lithium melting method with the sintered body as the substrate, and finally forming an oxide solid-state battery.

[0053] The present application not only provides a preparation process of an oxide solid-state battery, but also provides an oxide solid-state battery prepared based on the preparation process. Referring to Figure 1 , the oxide solid-state battery includes a positive electrode layer 4, a positive electrode and electrolyte transition layer 3, an electrolyte layer 2 and a negative electrode layer 1, which are four layers in total. The positive electrode and electrolyte transition layer 3 is a gradient material layer gradually transitioning from the positive electrode material to the electrolyte material; the electrolyte layer 2 has a certain thickness of micropores a with sharp corners facing the negative electrode layer 1 on the side close to the negative electrode layer 1, as shown in Figure 3 .

[0054] Based on the above preparation process, the oxide solid-state battery obtained by the present application includes a negative electrode layer 1, an electrolyte layer 2, a positive electrode and electrolyte transition layer 3 and a positive electrode layer 4, and the structure is as shown in Figure 1As shown in the figure; wherein the negative electrode layer 1, the electrolyte layer 2 and the positive electrode and electrolyte transition layer 3 are sequentially formed on the positive electrode layer 4 from bottom to top; preferably, the electrolyte layer 2 contains micro-holes a structure; the micro-holes a are multiple, and the multiple micro-holes a are uniformly filled in the electrolyte layer 2; preferably, the micro-holes a are in the shape of water droplets or pyramids as a whole; the sharp corners of the micro-holes a are directed towards the negative electrode layer 1; preferably, the contact surface between the electrolyte layer 2 and the negative electrode layer 1 is a non-smooth surface; preferably, the roughness Ra of the contact surface between the electrolyte layer 2 and the negative electrode layer 1 is 5-20.

[0055] The technical solutions provided by the present application will be described in detail below in combination with specific embodiments:

[0056] Example 1: Thin film type oxide solid-state lithium battery structure and preparation method thereof

[0057] 1. Structure of solid-state battery and raw material processing

[0058] The structure of the solid-state battery comprises a positive electrode layer 4, a positive electrode and electrolyte transition layer 3, an electrolyte layer 2 and a negative electrode layer 1, which are four layers in total. The contact surface between the electrolyte layer 2 and the negative electrode layer 1 is a rough surface with Ra5.

[0059] Raw material processing: the positive electrode material and the electrolyte material are respectively added into a ball mill, and high-hardness grinding balls are used in the ball mill to crush them, so that they become nanoscale raw materials that can be used by a material spray forming device. After screening, they are loaded into the forming device. The pore-forming material paraffin powder is also subjected to nanoscale processing so that it can be used by the material spray forming device. For example, in Example 1, lithium cobaltate is selected as the positive electrode material, Li 6.4 Ga 0.2 La3Zr2O 12 , and lithium alloy is selected as the negative electrode material.

[0060] 2. Additive manufacturing of the positive electrode layer 4 and the electrolyte layer 2

[0061] A material spray forming device is used for printing, and the substrate is a current collector. The positive electrode layer 4, the positive electrode and electrolyte transition layer 3 and the electrolyte layer 2 are sequentially printed on the substrate. The positive electrode material is printed for 6 layers; the positive electrode and electrolyte transition layer 3 is printed for 3 layers, and the proportion of the positive electrode material in each layer is 75%, 50% and 25% in turn, and the same material is connected between the layers; the electrolyte material is printed for 6 layers by layer-by-layer printing, as shown in Figure 2 In the layer-by-layer printing process, different nozzles are used to spray paraffin powder and electrolyte material to form an electrolyte layer containing micro-holes a, and the structure is as shown in Figure 3 .

[0062] 3. Hot pressing and co-sintering of the positive electrode layer 4 and the electrolyte layer 2

[0063] The sintering of the positive electrode layer 4 and the electrolyte layer 2 is carried out at a temperature slightly lower than the melting point of the material with the lowest melting point among the positive electrode layer 4 and the electrolyte layer 2, so that the pore-forming material in the electrolyte layer 2 is completely excluded, leaving the micropores a of the preset shape and size, while the rest of the electrolyte layer 2 is completely densified except for the designed micropores a. For example, the micropores a of the electrolyte layer 2 are located in the 4, 5 layers, and the pore type at this position is achieved by filling paraffin powder.

[0064] 4. Introduction of lithium negative electrode material.

[0065] The negative electrode is introduced on the negative electrode layer 1 side of the sintered body of the positive electrode layer 4 and the electrolyte layer 2 by lithium melting method under negative pressure. Before introduction, the sintered body of the positive electrode layer 4 and the electrolyte layer 2 needs to be preheated, and the preheating temperature is 150°C.

[0066] Example 2: A non-thin film type oxide solid-state lithium battery structure and its preparation method

[0067] 1. Structure design of solid-state battery and raw material processing;

[0068] The structure of the solid-state battery includes a positive electrode layer 4, a positive electrode and electrolyte transition layer 3, an electrolyte layer 2, and a negative electrode layer 1, a total of four layers. The positive electrode and electrolyte transition layer 3 is a gradient material layer gradually transitioning from positive electrode material to electrolyte material; the electrolyte layer 2 has a certain thickness of micropores a with sharp corners facing the negative electrode side, and the contact surface between the electrolyte layer 2 and the negative electrode is a rough surface with Ra20.

[0069] Raw material processing: the positive electrode material and the electrolyte material are respectively added to the ball mill, and the high-hardness grinding balls are used in the ball mill to crush them, so that they become nanoscale raw materials that can be used by the material spray forming equipment, and after screening, they are loaded into the forming equipment; the pore-forming material POM powder is also nanosized to be used by the material spray forming equipment. For example, in Example 2, the positive electrode material is lithium iron phosphate, the electrolyte material is Li7La3Zr 1.75 Ta 0.25 Ga 0.2 O 12 , and the negative electrode material is lithium alloy.

[0070] 2. Additive manufacturing of positive electrode layer 4 and electrolyte layer 2;

[0071] Printing is performed using a material jet forming device, with the current collector as the substrate, and printing in the order of positive electrode layer 4, positive electrode and electrolyte transition layer 3, and electrolyte layer 2 on the substrate. The positive electrode material is printed for 20 layers; the positive electrode and electrolyte transition layer 3 is printed for 7 layers, and the proportion of positive electrode material in each layer is 87.5%, 75%, 62.5%, 50%, 37.5%, 25%, and 12.5% in turn, and the same material is connected between layers; the electrolyte material is printed for 30 layers, and the micropores a of the electrolyte layer 2 are located in layers 21-25, and the pore type at this position is realized by filling POM powder.

[0072] 3. Hot-press co-sintering of the positive electrode layer 4 and the electrolyte layer 2;

[0073] Hot-press sintering is performed at a temperature slightly lower than the melting point of the lowest material of the positive electrode layer 4 and the electrolyte layer 2, so that the pore-forming material in the electrolyte layer 2 is completely excluded, leaving micropores a of a predetermined shape and size, and the remaining part is completely densified except for the designed micropores a.

[0074] 4. Introduction of lithium negative electrode material.

[0075] The negative electrode is introduced by lithium melting method on the negative electrode layer 1 side of the sintered body of the positive electrode layer 4 and the electrolyte layer 2. Before introduction, the sintered body of the positive electrode layer 4 and the electrolyte layer 2 needs to be preheated, and the preheating temperature is 180°C.

Claims

1. A process for the preparation of an oxide solid state battery, characterized in that: The preparation process of the oxide solid-state battery comprises the following steps: 1) preparing materials for the solid-state battery; the materials for the solid-state battery comprise positive electrode materials, electrolyte materials, negative electrode materials, and pore-forming materials; 2) preparing the positive electrode materials, electrolyte materials, and pore-forming materials into nanoscale raw material powders respectively; 3) layer by layer printing the nanoscale raw material powders prepared in step 2) according to the material spray forming process respectively to form a composite structure of a positive electrode layer-a positive electrode and electrolyte transition layer-an electrolyte layer; the nanoscale raw material powders comprise nanoscale positive electrode materials and nanoscale electrolyte materials, and nanoscale pore-forming materials; the positive electrode and electrolyte transition layer comprises a plurality of transition sub-layers, and the use amount of nanoscale positive electrode materials in each transition sub-layer decreases in turn along the direction from the positive electrode layer (4) to the positive electrode and electrolyte transition layer (3), the use amount of nanoscale electrolyte materials in each transition sub-layer increases in turn, and any material of each transition sub-layer is connected to the same material of the adjacent transition sub-layer; specifically: 3.1) taking a current collector as a substrate, spraying nanoscale positive electrode materials on the current collector according to the material spray forming process to form a positive electrode layer (4); 3.2) taking the positive electrode layer (4) as a substrate, layer by layer spraying nanoscale positive electrode materials and nanoscale electrolyte materials on the positive electrode layer (4) according to the material spray forming process to form a positive electrode and electrolyte transition layer (3) on the positive electrode layer (4); 3.3) taking the positive electrode and electrolyte transition layer (3) as a substrate, spraying nanoscale electrolyte materials and nanoscale pore-forming materials on the positive electrode and electrolyte transition layer (3) as needed according to the material spray forming process to finally form a composite structure of a positive electrode layer-a positive electrode and electrolyte transition layer-an electrolyte layer; 4) heat pressing and sintering the composite structure of a positive electrode layer-a positive electrode and electrolyte transition layer-an electrolyte layer prepared in step 3) to form a sintered body; 5) introducing a negative electrode material to the electrolyte layer of the sintered body prepared in step 4) to form an oxide solid-state battery.

2. The process for the preparation of an oxide solid state battery according to claim 1, characterized in that: The step 3.3) is specifically: 3.3.1) taking the positive electrode and electrolyte transition layer (3) as a substrate, spraying nanoscale electrolyte materials on the positive electrode and electrolyte transition layer (3) according to the material spray forming process to form a basic electrolyte sub-layer; 3.3.2) taking the basic electrolyte sub-layer as a substrate, spraying nanoscale electrolyte materials and nanoscale pore-forming materials on the basic electrolyte sub-layer as needed according to the material spray forming process by using different spray heads to form an electrolyte sub-layer containing pore-forming materials; The basic electrolyte sub-layer and the electrolyte sub-layer containing pore-forming materials form an electrolyte layer (2) as a whole; the positive electrode layer (4), the positive electrode and electrolyte transition layer (3), and the electrolyte layer (2) finally form a composite structure of a positive electrode layer-a positive electrode and electrolyte transition layer-an electrolyte layer.

3. The preparation process of the oxide solid-state battery according to claim 1, wherein the step 4) is specifically: 4.1) Designing a hot-press sintering temperature according to a melting point of the positive electrode material, a melting point of the electrolyte material, and a melting point of the pore-forming material; the hot-press sintering temperature is T, the melting point of the positive electrode material is T 正 , the melting point of the electrolyte material is T 电 , and the melting point of the pore-forming material is T 造 ; T 正 >T>T 造 ; T 电 >T>T 造 ; 4.2) hot-press sintering the composite structure of the anode layer-anode and electrolyte transition layer-electrolyte layer prepared in step 3) at a hot-press sintering temperature T, to remove the pore-forming material in the electrolyte layer (2) and form micropores (a) in the electrolyte layer (2) and form a densified sintered body.

4. The process for the preparation of an oxide solid state battery according to claim 3, characterized in that: The step 5) is specifically: 5.1) preheating the sintered body, the preheating temperature being 150-180℃; 5.2) introducing the negative electrode material onto the electrolyte layer of the sintered body by using lithium melting method, to finally form an oxide solid-state battery.

5. The process for the preparation of an oxide solid state battery according to claim 4, characterized in that: The roughness Ra of the contact surface between the electrolyte layer (2) and the negative electrode layer (1) on the sintered body is 5-20.

6. Process for the preparation of an oxide solid state battery according to any one of claims 1-5, characterized in that: The positive electrode material is lithium manganate, lithium cobaltate, lithium iron phosphate, lithium nickel cobalt aluminum or lithium nickel cobalt manganese; the electrolyte material is Li 6.4 Ga 0.2 La3Zr2O 12 , Li 6.55 Ga 0.15 La3Zr2O 12 , Li 6.4 La3Zr 1.4 Ta 0.6 O 12 , Li 6.6 La3Zr 1.8 Mo 0.2 O 12 , Li 6.4 La3Zr 1.7 W 0.3 O 12 or Li7La3Zr 1.75 Ta 0.25 Ga 0.2 O 12 ; the pore-forming material is paraffin powder, PE, PP or POM; the negative electrode material is metallic lithium or lithium alloy.

7. An oxide solid-state battery prepared based on the preparation process of the oxide solid-state battery according to claim 6.

8. The oxide solid state battery of claim 7, wherein: The oxide solid-state battery comprises a negative electrode layer (1), an electrolyte layer (2), an anode-electrolyte transition layer (3) and an anode layer (4); the negative electrode layer (1), the electrolyte layer (2) and the anode-electrolyte transition layer (3) are sequentially formed on the anode layer (4) from bottom to top; the electrolyte layer (2) contains a micropore (a) structure; the micropores (a) are multiple, and the multiple micropores (a) are uniformly distributed in the electrolyte layer (2); the micropores (a) as a whole are in the shape of water droplets or a vertebral body; the sharp corners of the micropores (a) are directed towards the negative electrode layer (1); the contact surface between the electrolyte layer (2) and the negative electrode layer (1) is a non-smooth surface; and the roughness Ra of the contact surface between the electrolyte layer (2) and the negative electrode layer (1) is 5-20.

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