High-rate, long-cycle, and high-safety positive electrode plate for lithium batteries, method for manufacturing the same, and use thereof

Abstract

The present invention discloses a positive electrode plate for a lithium battery with high rate, long cycle and high safety. The positive electrode plate includes a current collector and a positive electrode material layer located on the surface of the current collector. The positive electrode material layer is Li 1-x1 Ti 1-x1 A x1 OPO4, Li 1-x1 Ti 1-x1 A x1 PO5, Li 2-y1 Ti 1-y1 A y1 OM1O4, Li 2-y1 Ti 1-y1 A y1 At least one first component selected from M1O5, where 0≦x1≦0.7, 0≦y1≦1, A includes at least one of Nb, Ta, and Sb, and M1 is at least one of Si and Ge. The positive electrode material layer further includes a second component. The first component or a mixture of the first component and the second component in the positive electrode material layer is dispersed between the positive electrode active material particles. A lithium battery including the positive electrode exhibits excellent rate characteristics, cycle characteristics, and safety. The present invention does not change the current mainstream manufacturing process of positive electrode plates, separators, and batteries, is compatible with the conventional mainstream manufacturing process of positive electrode plates of lithium ion batteries, and is suitable for large-scale application.

Description

Cross-reference of related applications

[0001] This application claims the benefits of Chinese Patent Application No. 202210113791.3, filed on 30 January 2022, the contents of which are incorporated herein by reference. [Technical Field]

[0002] This invention relates to the technical field of lithium batteries, and more particularly to a high-rate, long-cycle, and highly safe positive electrode plate for lithium batteries, a method for manufacturing the same, and its use. [Background technology]

[0003] Lithium-ion batteries have advantages such as high energy density, good cycle characteristics, long service life, low self-discharge, and no memory effect. Their application market is gradually expanding in energy storage, power batteries, and 3C electronics, and their future application potential is promising.

[0004] Lithium batteries are experiencing increasing energy density, providing superior range for power electronics products such as electric vehicles and digital devices. Increasing the load capacity and compressive density of the electrode plates, particularly the positive plate, is an effective way to increase the battery's energy density. However, as the load capacity and compressive density of the positive plate increase, the positive electrode active material layer thickens and the porosity decreases, making it difficult to transport lithium ions within the positive plate. This leads to severe battery polarization, a decrease in the battery's discharge ratio capacity and rate characteristics, and reduced cycle stability. Furthermore, as the energy density of batteries increases, it tends to become more difficult to guarantee battery safety. To date, no technology exists that can solve all of these problems simultaneously.

[0005] Existing methods for improving the rate characteristics of batteries are as follows:

[0006] Positive electrode surface doping: The invention application with publication number CN113224287A concerns strontium-doped ternary lithium-ion battery positive electrode material (Li 1-x Srx [Ni 1-y-z Co y M z O₂, where M is one of the metals Mn and Al, 0 < x ≤ 0.1, 0 < y ≤ 1, 0 < z ≤ 1), its manufacturing method, and its use are disclosed. By doping strontium metal ions to replace lithium sites, the degree of cation mixing is reduced, the lithium ion channel is expanded, the layered structure is stabilized, and the rate performance of the lithium battery is effectively improved. This method, while improving the rate performance, often brings the problem of accelerating the capacity decay of the material.

[0007] Existing methods for improving the safety of the battery are as follows.

[0008] Cathode coating: The invention application with publication number CN113809280A discloses a cathode material, its manufacturing, and its use, which manufactured a cathode material having a substantially planar coating effect by changing sintering technical means and utilizing the interaction of coating agents. The cathode material manufactured by this method has a wide coating range of the surface coating layer, greatly reduces the degree of erosion of material particles by the electrolyte, effectively reduces the occurrence probability of side reactions, and improves the safety of the material. However, there are disadvantages that the process of the method is complex and it affects the rate performance of the battery.

[0009] Use of electrolyte additives: The invention application with publication number CN113690490A discloses a phosphite-based lithium ion battery electrolyte additive that can effectively prevent the combustion and explosion of organic solvents, enhance the thermal stability of the electrolyte itself, enhance the stability of the cathode, and improve the cycle stability and safety of the battery. There are disadvantages that it impairs the electrical properties of the battery such as cycle performance and rate performance.

[0010] Adhesive application to separators: The invention patent application, publication number CN108963153B, discloses a separator for lithium-ion batteries and a method for manufacturing the same. By coating at least one surface of a base film layer with an aqueous ceramic slurry coating, and then coating the aqueous ceramic slurry coating and / or the surface of the base film layer with a composite adhesive layer of polyethylene glycol and polymethyl methacrylate, the resulting lithium-ion battery separator has good adhesive properties, prevents short circuits due to electrode misalignment, improves battery hardness, and significantly enhances battery safety. However, it has the disadvantage of impairing the battery's rate characteristics.

[0011] Existing methods to improve both the electrical characteristics and safety of batteries are as follows:

[0012] CN108365260B discloses a semi-solid electrolyte comprising a polymer, a ceramic electrolyte, a lithium salt, and an ionic liquid as raw material components. The ceramic electrolyte comprises a main phase of lithium titanium aluminum phosphate and a heterophase of TiP2O7 / TiO2. Preferably, the heterophase content in the ceramic electrolyte is 2-7%, and the mass ratio of TiP2O7 to TiO2 is 1.5-2.5:1. The overall properties of a semi-solid electrolyte manufactured using a ceramic electrolyte with the heterophase content described above are optimal. The heterophase having the special composition and content has lithium storage properties and can improve lithium ion transportability, as well as reduce contact between the main phase of lithium titanium aluminum phosphate and metallic lithium, thereby improving interfacial stability with metallic lithium. However, this patent does not improve the electrical properties and safety of the positive electrode, and the method is incompatible with existing mainstream manufacturing processes for lithium-ion battery positive electrode plates and is not suitable for large-scale applications.

[0013] CN113707880A relates to a positive electrode plate containing a solid electrolyte, a method for manufacturing the same, and its use, aiming to improve the rate characteristics of a battery and enhance the cycle characteristics and safety. The solid electrolyte contained in the positive electrode slurry facilitates the permeation and infiltration of the electrolyte in the lateral and longitudinal directions of the electrode plate, and also facilitates the storage and infiltration of the electrolyte. Therefore, during the cycling of the cell, it alleviates the expansion of the electrode plate, reduces the amount of electrolyte extruded under pressure during the expansion process of the electrode plate, enables the electrode plate to contain a rich electrolyte even after the cell undergoes long-term cycling, ensures the normal transport of lithium ions, and can improve the cycle characteristics. However, from the data of the examples, it can be seen that the battery capacity and safety only increase slightly, and there is no data to support the effect on the rate characteristics. It has been found that adding conventional solid electrolytes cannot achieve the purpose of comprehensively improving the electrical characteristics and safety of the battery.

[0014] Therefore, it is necessary to find a method with simple steps and low cost while improving the electrical characteristics and safety of the battery.

Summary of the Invention

[0015] In view of the limitations existing in the above prior art, the present invention provides a positive electrode plate for a lithium battery with high rate, long cycle, and high safety, a method for manufacturing the same, and its use. The positive electrode plate of the present invention includes a current collector and a positive electrode material layer located on the surface of the current collector, and the positive electrode material layer includes a positive electrode active material, a conductive agent, a binder, and a first component.

[0016] The first component is Li 1-x1 Ti 1-x1 A x1 OPO4, Li 1-x1 Ti 1-x1 A x1 PO5, Li 2-y1 Ti 1-y1 A y1 OM1O4, Li 2-y1 Ti 1-y1 A y1It contains at least one of M1O5. Here, 0 ≦ x1 ≦ 0.7, 0 ≦ y1 ≦ 1, A contains at least one of Nb, Ta, Sb, and M1 is at least one of Si and Ge.

[0017] Preferably, the first component is at least one of LiTiOPO4, Li 0.9 Nb 0.1 Ti 0.9 OPO4, Li 0.9 Ta 0.1 Ti 0.9 OPO4, Li2TiOSiO4, LiTaOGeO4, or the like.

[0018] The positive electrode material layer further contains a second component. The second component is at least one or a combination of one or more selected from LiM22(PO4)3, Li 1+x2 Al x2 M2 2-x2 (PO4)3, M2O2, Li 16-4y2 M2 y2 O8, M2P2O7, M3PO4, M32SiO5, M43(PO4)2, M42SiO4. Here, M2 is one selected from Ti, Ge, Zr, and Hf. Here, 0 < x2 < 0.6, and M3 and M4 are one of Al, Ga, Sc, Y, Ca, Sr, Zn, Si, In, Lu, La, Fe, Cr, Ge, and 3 < y2 < 4.

[0019] The second component is preferably one of InPO4, LATP, AlPO4, LAGP, LATP + AlPO4, LAGP + Al2SiO5, InPO4 + LATP, Al2SiO5, TiO2 + LiTi2(PO4)3, TiP2O7 + LiGe2(PO4)3.

[0020] The form of the mixed component composed of the first component and the second component is one in which the first component particles and the second component particles are uniformly mixed with each other, or one in which the first component crystal form and the second component crystal form are contained in each primary particle.

[0021] When the mass ratio of the first component to the cathode active material in the cathode material layer is w1, 0 < w1 < 5%, preferably 0.1 < w1 < 3%.

[0022] When the mass ratio of the second component to the cathode active material in the cathode material layer is w2, 0 ≤ w2 < 5%, preferably 0 ≤ w2 < 3%.

[0023] The particle size of the first component is 10 nm to 10 μm. Preferably, the particle size of the first component is 50 nm to 5OO nm.

[0024] The particle size of the second component is 10 nm to 10 μm. Preferably, the particle size of the second component is 50 nm to 5OO nm.

[0025] Preferably, taking the weight of the cathode material layer as 100%, the content of the cathode active material particles is 80 to 99 wt%, the content of the conductive agent is 0.1 to 8 wt%, the content of the binder is 0.1 to 10 wt%, the content of the first component or the mixed component composed of the first component and the second component is 0.1 to 6 wt%, Preferably, the cathode active material particles are at least one selected from lithium cobalt oxide cathode and its modified materials, NCM ternary cathode and its modified materials, NCA ternary cathode and its modified materials, lithium nickel manganese oxide cathode and its modified materials, lithium-rich cathode and its modified materials, lithium iron phosphate cathode and its modified materials, the conductive agent is at least one selected from Super-P, KS-6, carbon black, carbon nanofiber, carbon nanotube, acetylene black, or graphene, the binder is selected from polyvinylidene fluoride, polyvinylidene fluoride - hexafluoropropylene, polytetrafluoroethylene, homopolymers, copolymers, modified compounds of the above polymers, or mixtures of the above polymers with other polymers or small molecules.

[0026] A second object of the present invention is to provide a method for manufacturing a positive electrode plate for a lithium battery according to the first object of the present invention, wherein the first component or a mixture of the first and second components is blended into a homogenate in a positive electrode slurry. In manufacturing the positive electrode plate, the first component or a mixture of the first and second components is added and dispersed between the positive electrode active material particles.

[0027] Preferably, the manufacturing method is Step 1 involves uniformly mixing the first component or a mixture of the first and second components, a positive electrode active material, a conductive additive, a binder, and a solvent to form a slurry. Step 2 involves applying the slurry obtained in Step 1 to the surface of the aluminum current collector to form a positive electrode plate. Step 3 includes blow-drying and vacuum-drying the electrode plates obtained in Step 2 to obtain the final positive electrode plate.

[0028] Preferably, In step 1, NMP is used as the solvent in the slurry, and the mass ratio of NMP to cathode material is (2000~10):100.

[0029] In Step 2, The manufacturing slurry used has a viscosity value of 3500-8500 mPa·s at 25°C.

[0030] In step 3, The aforementioned forced-air drying is performed at a temperature of 80-180°C for 10 minutes to 9 hours, while the vacuum drying is performed at a temperature of 80-180°C for 3 to 100 hours.

[0031] A third object of the present invention is to provide the use of the positive electrode plate described in the first object of the present invention in a lithium battery.

[0032] In this invention, by adding a first component or a mixture of the first and second components with a particle size D50 of 0.01 to 10 μm to the positive electrode plate and compounding it with a conductive agent and a binder, the rate characteristics, cycle characteristics, and safety of the battery are improved, resulting in a battery with high rate, long cycle, and high safety. Conventionally, the first component in this invention is usually a heterophase generated during the sintering process of the solid electrolyte. The presence of the heterophase generally reduces the ionic conductivity of the solid electrolyte and usually needs to be removed when manufacturing the solid electrolyte. Conventional technology does not actively introduce the first component into the electrolyte in high-safety, high-rate lithium batteries. However, in many experiments, the first component in this invention has completely different properties from the solid electrolyte, and the ionic conductivity of such a component is relatively low, about 10 times that of a typical solid electrolyte. -4 It is much smaller than S / cm (i.e., it cannot be used as an electrode material by replacing a solid electrolyte), and the ionic conductivity of the electrolyte is 10 -2 Although the first component is smaller than S / cm and does not directly contribute to ionic conductivity after mixing with the electrolyte, its specific chemical composition can contribute to the formation of CEI on the surface of the cathode material when added to the cathode material. This alters the composition of the CEI, making it more stable, thus avoiding CEI rupture and the resulting battery polarization and thermal runaway. Furthermore, it can improve the rate characteristics, cycle characteristics, and safety of the cathode plate during actual battery operation. Adding the second component to the mixed cathode suppresses the decomposition of the electrolyte and inhibits the formation of insulating components on the cathode material surface. In other words, using the second and first components simultaneously produces a synergistic effect, creating a superior CEI and comprehensively improving the electrical characteristics and safety of the battery. Moreover, by simultaneously introducing the first component or a mixture of the first and second components into the cathode using a blending method, it becomes unnecessary to change the current mainstream manufacturing processes for cathode plates, separators, and batteries, offering the advantages of high stability and low cost, making it suitable for large-scale applications.

[0033] The present invention has the following advantages and remarkable effects compared to the prior art.

[0034] The first component or a mixture of the first and second components particles added to the positive electrode plate of the lithium battery of the present invention have high chemical stability, can be directly blended into the positive electrode active material before the manufacture of the positive electrode plate, and do not require changes to the current mainstream manufacturing processes for positive electrode plates, separators, and batteries. They are compatible with the mainstream manufacturing processes for existing lithium-ion battery positive electrode plates, do not affect the manufacturing processes for the positive electrode and cell, and have the advantages of high stability and low cost, making them suitable for large-scale applications. On the other hand, methods for doping positive electrode materials or coating positive electrode surfaces both require changes to existing manufacturing technologies for positive electrode materials, and it is difficult to improve the discharge ratio capacity and rate characteristics.

[0035] The first component added to the lithium battery positive electrode plate of the present invention is completely different from conventional solid electrolytes, having low lithium ion conductivity and being completely unsuitable as a solid electrolyte material. In the prior art, it was common to select additive components with high lithium ion conductivity to improve the electrical characteristics of batteries. However, in the present invention, by creatively adding the first component with low lithium ion conductivity to the positive electrode, the CEI of the positive electrode surface can be improved, significantly enhancing the battery's rate characteristics, cycle characteristics, and safety, thus overcoming the biases of existing technology. Mixed component particles of the first and second components, simultaneously added to the lithium battery positive electrode plate of the present invention, improve the stability of the CEI on the positive electrode particle surface, suppress oxygen release from the positive electrode and reaction with the electrolyte during thermal runaway, suppress electrolyte decomposition, and improve the electrical characteristics and safety of the battery. Experiments have shown that the synergistic effect is better when the first and second components are used simultaneously.

[0036] The content of the first component or a mixture of the first and second components added to the positive electrode plate for lithium batteries of the present invention is specially designed. If the content is less than 0.1% by weight, it is difficult to form an effective CEI layer, and the improvement in electrical characteristics and safety is insufficient. If the content exceeds 6% by weight, the content of inactive material in the battery increases, and the energy density of the battery decreases. The resulting positive electrode exhibits excellent rate characteristics, cycle characteristics, and safety. [Brief explanation of the drawing]

[0037] [Figure 1] This is a schematic diagram of the structure of the positive electrode plate for the lithium battery in Example 2. [Figure 2] This is a schematic diagram of the structure of the positive electrode plate for the lithium battery in Example 1. [Figure 3] This is a schematic diagram of a heavy object impact test for the lithium battery of the present invention. [Figure 4] This is a schematic diagram of the structure of the positive electrode plate for the lithium battery in Example 11. [Modes for carrying out the invention]

[0038] The present invention will be described in detail below with reference to specific drawings and embodiments. The following embodiments are for further explanation of the present invention and should not be understood as limiting the scope of protection of the present invention. Non-essential improvements and modifications of the present invention made by those skilled in the art based on the content of the present invention also fall within the scope of protection of the present invention. Example 1

[0039] Step 1: First component LiTiOPO4 and second component Li 1.4 Al 0.4 Ti 1.6 A slurry was formed by uniformly mixing 1 kg of a mixed component consisting of (PO4)3, 100 kg of NCM90 as the positive electrode active material, 1 kg of Super P, 1 kg of PVDF, and 500 kg of NMP solvent. Step 2: The slurry obtained in Step 1 was applied to the surface of the aluminum current collector to form a positive electrode plate. Step 3: The electrode plates obtained in Step 2 were baked at 95°C for 5 minutes, then roll-pressed and die-cut using a 28T roll press to obtain a positive electrode plate with a layer thickness of 126 μm. The positive electrode plate was then vacuum-dried at 105°C for 24 hours to obtain the final positive electrode plate. The ratio of the content of the first component to the second component is 1:4, and the particle size D50 of the particles of the first and second components is 200 nm each. The positive electrode plate for the lithium battery manufactured by the above method includes a positive electrode material layer and a current collector 3, as shown in the schematic structural diagram of Figure 2. The positive electrode material layer includes a positive electrode active material 1, a conductive agent, a binder, a first component 2, and a second component 4, and the first component 2 and the second component 4 in the positive electrode material layer are dispersed between particles of the positive electrode active material 1. A soft pack lithium battery was assembled by combining the positive electrode plate and an SiOC650 negative electrode. After processes such as liquid injection, chemical conversion, and capacity grading were performed on the lithium battery manufactured as described above, electrochemical tests and safety tests were conducted, respectively. The specific test results for electrochemical properties are shown in Table 1, and the safety test results are shown in Table 2. The test method for the electrochemical properties of the lithium battery used in this invention is as follows. 1. Testing cycle characteristics a) At 23℃±2℃, charge with a constant current of 1C until the charging termination voltage is reached, then switch to constant voltage charging. When the charging current rate drops to 0.05C, stop charging and leave for 1 hour. b) Discharge the battery at a constant current of 1C until it reaches the discharge termination voltage, then stop the discharge, record the discharge capacity, and this completes one cycle. c) Repeat steps a and b until the discharge capacity falls below 80% of the discharge capacity of the first cycle, and record the total number of battery cycles at that point. 2. Rate Test a) Charge the batteries at 23℃±2℃ at rates of 0.1C, 0.2C, 0.33C, 1C, 2C, and 3C, respectively, until they reach the charging termination voltage. Then discharge them at the same rate current until they reach the discharge termination voltage, performing four cycles at each rate. b) Record the discharge capacity at each rate. c) Calculate the ratio of the 2C or 3C discharge capacity to the 0.33C discharge capacity, express it as 2C / 0.33C or 3C / 0.33C, and evaluate the rate characteristics. 3. High-temperature cycle a) At 45°C, constant current charging is performed at a current of 1C until the charging termination voltage is reached, then the system switches to constant voltage charging, and charging stops when the charging current rate drops to 0.05C. b) Leave the battery undisturbed at 45°C for 5 hours. c) Under high temperature conditions of 45°C, discharge the battery at a constant current of 1C until the discharge termination voltage is reached, then stop the discharge, record the discharge capacity, and this completes one cycle. d) Repeat steps a to c until the discharge capacity falls below 80% of the discharge capacity of the first cycle, and record the battery's discharge capacity and the total number of cycles at that point. The safety testing methods for lithium-ion batteries are as follows: 1. Overcharging a) At 23℃±2℃, charge with a constant current of 1C until the charging termination voltage is reached, then switch to constant voltage charging. When the charging current rate drops to 0.05C, stop charging and leave for 1 hour. b) Continue charging the battery with a constant current of 1C until thermal runaway occurs, and record the voltage value of the battery when thermal runaway begins. 2. Hotbox a) At 23℃±2℃, charge with a constant current of 1C until the charging termination voltage is reached, then switch to constant voltage charging. When the charging current rate drops to 0.05C, stop charging and leave for 1 hour. b) Place the battery in the test box. Heat the test box at a rate of 5°C / min until the temperature inside the box reaches 160°C ± 2°C, then maintain a constant temperature for 1 hour. The battery will pass if it does not emit smoke, catch fire, or explode; otherwise, it will fail. 3.Falling a) At 23℃±2℃, charge with a constant current of 1C until the charging termination voltage is reached, then switch to constant voltage charging. When the charging current rate drops to 0.05C, stop charging and leave for 1 hour. b) A sample is dropped from a height of 1 meter onto a concrete slab. Each side of the soft pack battery will be dropped once, for a total of six tests. After six experiments, the battery will pass if it does not smoke, catch fire, or explode; otherwise, it will fail. 4. Impact from heavy objects a) At 23℃±2℃, charge with a constant current of 1C until the charging termination voltage is reached, then switch to constant voltage charging. When the charging current rate drops to 0.05C, stop charging and leave for 1 hour. b) A battery 8 is placed on the surface of the platform, a metal rod 9 with a diameter of 15.8 mm ± 0.2 mm is placed horizontally on the top surface of the geometric center of the battery, and a heavy object with a mass of 9.1 kg ± 0.1 kg is dropped from a height of 610 mm ± 25 mm into the surface of the battery on which the metal rod is placed, and the test is observed for 6 hours. A schematic diagram of the heavy object impact test is shown in Figure 3, where 5 is a towing rope, 6 is a guide pipe, and 7 is a steel impact box (hinged door is not shown). The impact test will be performed only on a wide surface of the soft pack battery, and each sample will be subjected to only one impact test. The battery will pass if it does not emit smoke, catch fire, or explode; otherwise, it will fail. 5. Piercing a) At 23℃±2℃, charge with a constant current of 1C until the charging termination voltage is reached, then switch to constant voltage charging. When the charging current rate drops to 0.05C, stop charging and leave for 1 hour. b) Using a φ8mm high-temperature resistant steel needle (with a conical angle of 45° at the tip, a glossy surface, and no rust, oxide layer, or oil stains), the needle is inserted at a speed of 25 mm / s from a direction perpendicular to the battery plates, at the geometric center of the surface into which the battery is inserted, leaving the steel needle inside the battery. c) Observe for 1 hour. The battery will pass if it does not emit smoke, catch fire, or explode; otherwise, it will fail. Example 2

[0040] Except for changing the mixed component (1 kg) consisting of the first and second components to one containing only the first component and excluding the second component, changing the positive electrode active material to NCM83, and changing the battery structure to NCM83||SiOC650, all other parameters were kept the same as in Example 1. The manufactured lithium battery positive electrode plate, as shown in the schematic structural diagram of Figure 1, includes a positive electrode material layer and a current collector 3. The positive electrode material layer contains a positive electrode active material 1, a conductive agent, a binder, and the first component 2, and the first component 2 in the positive electrode material layer is dispersed between the particles of the positive electrode active material 1. After processes such as liquid injection, chemical conversion, and capacity grading were performed on the lithium battery manufactured as described above, electrochemical tests and safety tests were conducted, respectively. The specific test results of the electrochemical properties of the lithium battery manufactured using this positive electrode plate are shown in Table 1, and the safety test results are shown in Table 2. Example 3

[0041] Except for changing the second component to AlPO4, changing the negative electrode to SiOC450, and changing the battery structure to NCM83||SiOC450, all other parameters were the same as in Example 1. After performing processes such as liquid injection, chemical conversion, and capacity grading on the lithium batteries manufactured as described above, electrochemical tests and safety tests were performed, respectively. The specific test results for the electrochemical properties of the manufactured lithium batteries are shown in Table 1, and the safety test results are shown in Table 2. Example 4

[0042] The second component is Li 1.4 Al 0.4 Ti 1.6 (PO4)3 and AlPO4 are changed, and the Li in the first and second components is changed. 1.4 Al 0.4 Ti 1.6Except for setting the mass ratio of (PO4)3 and AlPO4 to 1:8:1, changing the positive electrode active material to LCO, changing the negative electrode to SiOC450, and setting the battery structure to LCO||SiOC450, all other parameters were the same as in Example 1. After performing processes such as liquid injection, chemical conversion, and capacity grading on the lithium batteries manufactured as described above, electrochemical tests and safety tests were performed, respectively. The specific test results for the electrochemical properties of the manufactured lithium batteries are shown in Table 1, and the safety test results are shown in Table 2. Example 5

[0043] Except for changing the mixed component (1 kg) consisting of the first and second components to one containing only the first component, LiTaOSiO4 (1 kg), and omitting the second component, changing the positive electrode active material to LFP, changing the negative electrode to graphite, and changing the battery structure to graphite||LFP, all other parameters were kept the same as in Example 1. After processes such as liquid injection, chemical conversion, and capacity grading were carried out on the lithium batteries manufactured as described above, electrochemical tests and safety tests were performed, respectively. The specific test results for the electrochemical properties of the manufactured lithium batteries are shown in Table 1, and the safety test results are shown in Table 2. Example 6

[0044] The first component was changed to LiTaOSiO4, and the second component was changed to Li 1.4 Al 0.4 Ge 1.6 Except for changing the material to (PO4)3, changing the positive electrode active material to NCM83, changing the negative electrode to graphite, and changing the battery structure to graphite||NCM83, all other parameters were the same as in Example 1. After processes such as liquid injection, chemical conversion, and capacity grading were carried out on the lithium batteries manufactured as described above, electrochemical tests and safety tests were performed, respectively. The specific test results for the electrochemical properties of the manufactured lithium batteries are shown in Table 1, and the safety test results are shown in Table 2. Example 7

[0045] A 1 kg mixture of the first and second components was modified to contain only the first component, LiTaOGeO4, 1 kg, and omit the second component, while other parameters were kept the same as in Example 1. After processes such as liquid injection, chemical conversion, and capacity grading were performed on the lithium batteries manufactured as described above, electrochemical tests and safety tests were conducted, respectively. The specific test results for the electrochemical properties of the manufactured lithium batteries are shown in Table 1, and the safety test results are shown in Table 2. Example 8 Except for changing the first component to LiTaOGeO4, the second component to Al2SiO5, the positive electrode active material to NCM83, and the battery structure to NCM83||SiOC650, all other parameters were the same as in Example 1. After performing processes such as liquid injection, chemical conversion, and capacity grading on the lithium batteries manufactured as described above, electrochemical tests and safety tests were performed, respectively. The specific test results for the electrochemical properties of the manufactured lithium batteries are shown in Table 1, and the safety test results are shown in Table 2. Example 9

[0046] The second component is Li 1.4 Al 0.4 Ti 1.6 (PO4)3 and AlPO4 are changed, and the Li in the first and second components is changed. 1.4 Al 0.4 Ti 1.6 Except for changing the mass ratio of (PO4)3 and AlPO4 to 1:8:1 and the particle size D50 of the first and second component particles to 50 nm, all other parameters were the same as in Example 1. After the lithium batteries manufactured as described above underwent processes such as liquid injection, chemical conversion, and capacity grading, electrochemical tests and safety tests were performed, respectively. The specific test results for the electrochemical properties of the manufactured lithium batteries are shown in Table 1, and the safety test results are shown in Table 2. Example 10

[0047] The second component is Li 1.4 Al 0.4 Ti 1.6Except for changing the composition to (PO4)3 and AlPO4, changing the ratio of the first and second components to 1:8:1, and changing the particle size D50 of the first and second component particles to 500 nm, other parameters were kept the same as in Example 1. After the lithium batteries manufactured as described above underwent processes such as liquid injection, chemical conversion, and capacity grading, electrochemical tests and safety tests were performed, respectively. The specific test results for the electrochemical properties of the manufactured lithium batteries are shown in Table 1, and the safety test results are shown in Table 2. Example 11

[0048] The total amount of the mixed component, which consists of the first and second components, was changed to 0.5 kg, and the second component was changed to Li 1.4 Al 0.4 Ti 1.6 (PO4)3 and AlPO4 are changed, and the Li in the first and second components is changed. 1.4 Al 0.4 Ti 1.6 The mass ratio of (PO4)3 and AlPO4 was set to 1:8:1. Each primary particle of the mixed component contained both the first and second crystalline forms of the first component, and the particle size D50 of the primary particles of the mixed component was 200 nm. The mixed form is shown in Figure 4, where 1 is the active material, 2 is the mixed component of the first and second components in the same particle, and 3 is the current collector. Other parameters were the same as in Example 1. After processes such as liquid injection, chemical conversion, and capacity grading were performed on the lithium batteries manufactured as described above, electrochemical tests and safety tests were performed, respectively. The specific test results of the electrochemical properties of the manufactured lithium batteries are shown in Table 1, and the safety test results are shown in Table 2. Example 12

[0049] The total amount of the mixed component, which consists of the first and second components, was changed to 5 kg, and the second component was changed to Li 1.4 Al 0.4 Ti 1.6Except for changing (PO4)3 and AlPO4 and changing the ratio of the first and second components to 1:8:1, other parameters were the same as in Example 1. After the lithium batteries manufactured as described above underwent processes such as liquid injection, chemical conversion, and capacity grading, electrochemical tests and safety tests were performed, respectively. The specific test results for the electrochemical properties of the manufactured lithium batteries are shown in Table 1, and the safety test results are shown in Table 2. Comparative Example 1

[0050] Except for the absence of the first and second components, all other parameters were the same as in Example 1. After the lithium batteries manufactured as described above underwent processes such as liquid injection, chemical conversion, and capacity grading, electrochemical tests and safety tests were performed, respectively. The specific test results for the electrochemical properties of the manufactured lithium batteries are shown in Table 1, and the safety test results are shown in Table 2. Comparative Example 2

[0051] Except for omitting the first and second components, changing the positive electrode active material to NCM83, and using NCM83||SiOC650 for the battery structure, all other parameters were the same as in Example 1. After processes such as liquid injection, chemical conversion, and capacity grading were performed on the lithium batteries manufactured as described above, electrochemical tests and safety tests were conducted, respectively. The specific test results for the electrochemical properties of the manufactured lithium batteries are shown in Table 1, and the safety test results are shown in Table 2. Comparative Example 3

[0052] Except for omitting the first and second components, changing the positive electrode active material to NCM83, changing the negative electrode to SiOC450, and changing the battery structure to NCM83||SiOC450, all other parameters were the same as in Example 1. After processes such as liquid injection, chemical conversion, and capacity grading were carried out on the lithium batteries manufactured as described above, electrochemical tests and safety tests were performed, respectively. The specific test results for the electrochemical properties of the manufactured lithium batteries are shown in Table 1, and the safety test results are shown in Table 2. Comparative Example 4

[0053] Except for omitting the first and second components, changing the positive electrode active material to LCO, changing the negative electrode to SiOC450, and changing the battery structure to LCO||SiOC450, all other parameters were the same as in Example 1. After processes such as liquid injection, chemical conversion, and capacity grading were carried out on the lithium batteries manufactured as described above, electrochemical tests and safety tests were performed, respectively. The specific test results for the electrochemical properties of the manufactured lithium batteries are shown in Table 1, and the safety test results are shown in Table 2. Comparative Example 5

[0054] Except for omitting the first and second components, changing the positive electrode active material to LFP, using graphite for the negative electrode, and using LFP||graphite for the battery structure, all other parameters were the same as in Example 1. After processes such as liquid injection, chemical conversion, and capacity grading were carried out on the lithium batteries manufactured as described above, electrochemical tests and safety tests were performed, respectively. The specific test results for the electrochemical properties of the manufactured lithium batteries are shown in Table 1, and the safety test results are shown in Table 2. Comparative Example 6

[0055] Except for omitting the first and second components, changing the positive electrode active material to NCM83, using graphite for the negative electrode, and using NCM83||graphite for the battery structure, all other parameters were the same as in Example 1. After processes such as liquid injection, chemical conversion, and capacity grading were performed on the lithium batteries manufactured as described above, electrochemical tests and safety tests were conducted, respectively. The specific test results for the electrochemical properties of the manufactured lithium batteries are shown in Table 1, and the safety test results are shown in Table 2. Comparative Example 7

[0056] Except for replacing 1 kg of the mixed component consisting of the first and second components with 1 kg of Al2O3, all other parameters were the same as in Example 1. After the lithium batteries manufactured as described above underwent processes such as liquid injection, chemical conversion, and capacity grading, electrochemical tests and safety tests were performed, respectively. The specific test results for the electrochemical properties of the manufactured lithium batteries are shown in Table 1, and the safety test results are shown in Table 2. Comparative Example 8

[0057] Except for replacing 1 kg of the mixed component, which consists of the first and second components, with 1 kg of ZnO, changing the positive electrode active material to NCM83, and changing the battery structure to NCM83||SiOC650, all other parameters were the same as in Example 1. After processes such as liquid injection, chemical conversion, and capacity grading were carried out on the lithium batteries manufactured as described above, electrochemical tests and safety tests were performed, respectively. The specific test results for the electrochemical properties of the manufactured lithium batteries are shown in Table 1, and the safety test results are shown in Table 2. Comparative Example 9

[0058] 1 kg of the mixed component, which consists of the first component and the second component, is Li 1.4 Al 0.4 Ti 1.6 Except for changing the (PO4) content to 31 kg, changing the positive electrode active material to NCM83, changing the negative electrode to SiOC450, and changing the battery structure to NCM83||SiOC450, all other parameters were the same as in Example 1. After the lithium batteries manufactured as described above underwent processes such as liquid injection, chemical conversion, and capacity grading, electrochemical tests and safety tests were performed, respectively. The specific test results for the electrochemical properties of the manufactured lithium batteries are shown in Table 1, and the safety test results are shown in Table 2. Comparative Example 10

[0059] Except for replacing 1 kg of the mixed component consisting of the first and second components with 1 kg of AlPO4, changing the positive electrode active material to LCO, changing the negative electrode to SiOC450, and changing the battery structure to LCO||SiOC450, all other parameters were the same as in Example 1. After processes such as liquid injection, chemical conversion, and capacity grading were carried out on the lithium batteries manufactured as described above, electrochemical tests and safety tests were performed, respectively. The specific test results for the electrochemical properties of the manufactured lithium batteries are shown in Table 1, and the safety test results are shown in Table 2. Comparative Example 11

[0060] 1 kg of the mixed component, which consists of the first component and the second component, is Li 0.5 La 0.5Except for changing the TiO3 to 1kg, omitting the second component, changing the positive electrode active material to LFP, changing the negative electrode to graphite, and changing the battery structure to LFP||graphite, all other parameters were the same as in Example 1. After processes such as liquid injection, chemical conversion, and capacity grading were carried out on the lithium batteries manufactured as described above, electrochemical tests and safety tests were performed, respectively. The specific test results for the electrochemical properties of the manufactured lithium batteries are shown in Table 1, and the safety test results are shown in Table 2. Comparative Example 12

[0061] 1 kg of the mixed component, which consists of the first component and the second component, is converted to Li7La3Zr2O 12 Except for changing the weight to 1 kg, changing the positive electrode active material to NCM83, changing the negative electrode to graphite, and changing the battery structure to NCM83||graphite, all other parameters were the same as in Example 1. After processes such as liquid injection, chemical conversion, and capacity grading were carried out on the lithium batteries manufactured as described above, electrochemical tests and safety tests were performed, respectively. The specific test results for the electrochemical properties of the manufactured lithium batteries are shown in Table 1, and the safety test results are shown in Table 2. Table 1 shows the electrochemical properties data for the examples.

[0062] [Table 1] Table 2 shows the safety data for the examples.

[0063] [Table 2]

[0064] From the data in Tables 1 and 2, it can be seen that blending the first component or a mixture of the first and second components into the positive electrode can significantly improve the battery's rate characteristics, cycle characteristics, and safety. Comparing Example 5 with Comparative Example 11, it was found that blending the first component into the positive electrode is far more effective in improving battery rate characteristics, cycle characteristics, and safety than blending a solid electrolyte with high lithium ion conductivity, as constructing a high-efficiency CEI is key to improving the electrical characteristics and safety of liquid batteries and mixed solid-liquid batteries. As can be seen from the comparison between Example 1 and Example 7, a mixture of the first and second components blended together allows the first and second components to synergistically improve the CEI, thus further improving the battery's rate characteristics, cycle characteristics, and safety compared to blending only the first component. As can be seen from comparing Example 1 with Examples 9 and 10, there is an optimal particle size for the first and second components. Optimizing the particle size can improve the battery's rate characteristics and cycle characteristics. If the particle size is too small, the first component or the mixed component particles composed of the first and second components tend to aggregate. If the particle size is too large, the first component or the mixed component particles composed of the first and second components cannot adequately contact the surface of the active material particles. Both excessively small and excessively large particle sizes are detrimental to the construction of a stable CEI. As can be seen from comparing Example 1 with Comparative Examples 11 and 12, there is an optimal ratio for the amount of the first and second components added. If the amount is too low, the battery's rate characteristics and safety cannot be improved. If the amount is too high, the first component or the mixed component composed of the first and second components accumulates, forming regions with low lithium ion conductivity, thus preventing the achievement of higher rate characteristics.

[0065] The embodiments described above are merely exemplary embodiments used to illustrate the principles of the present invention, but it should be understood that the present invention is not limited thereto. Those skilled in the art can make various modifications and improvements without departing from the spirit and essence of the present invention, and such modifications and improvements are considered to be within the scope of the protection of the present invention.

Claims

1. A positive electrode plate for a liquid lithium battery or a mixed solid-liquid lithium battery comprising a positive electrode active material, a conductive agent, a binder, and a positive electrode material layer containing a first component, The first component is LiTiOPO ４ LiTaOSIO ４ LiTaOGeO ４ It is at least one of the following: The positive electrode active material is characterized by comprising at least one of the following: lithium cobalt oxide positive electrode and its modified material, NCM ternary positive electrode and its modified material, NCA ternary positive electrode and its modified material, lithium nickel manganate positive electrode and its modified material, lithium-rich positive electrode and its modified material, and lithium iron phosphate positive electrode and its modified material, as a positive electrode plate for liquid lithium batteries or mixed solid-liquid lithium batteries.

2. The positive electrode material layer further includes a second component, and the second component is LiM2 ２ (PO ４ ) ３ , Li １＋ｘ２ Al ｘ２ M2 ２－ｘ２ (PO ４ ) ３ , M2O ２ , Li １６－４ｙ２ M2 ｙ２ O ８ , M2P ２ O ７ , M3PO ４ , M3 ２ SiO ５ , M4 ３ (PO ４ ) ２ , M4 ２ SiO ４ , and is at least one or a combination of a plurality of species selected from these, where M2 is one selected from Ti, Ge, Zr, and Hf, where 0 < x2 < 0.6, and M3 and M4 are each independently any one selected from Al, Ga, Sc, Y, Ca, Sr, Zn, Si, In, Lu, La, Fe, Cr, Ge, and 3 < y2 < 4. The positive electrode plate according to claim 1, characterized in that.

3. The second component is InPO ４ , LATP, AlPO ４ , LAGP, LATP+AlPO ４ LAGP+Al ２ SiO ５ InPO ４ +LATP, Al ２ SiO ５ , TiO ２ +LiTi ２ (PO ４ ) ３ , Tip ２ O ７ +LiGe ２ (PO ４ ) ３ A positive electrode plate according to claim 2, characterized in that it is one of the types of positive electrodes.

4. The positive electrode plate according to claim 2, characterized in that the form of the mixed component composed of the first component and the second component is a uniform mixture of first component particles and second component particles, or in which each primary particle contains the crystalline form of the first component and the crystalline form of the second component.

5. The mass ratio of the first component in the positive electrode material layer to the positive electrode active material is w １ Therefore, 0 < w １ The positive electrode plate according to claim 1, characterized in that the first component is <5% and has a particle size of 10 nm to 10 μm.

6. The mass ratio of the first component in the positive electrode material layer to the positive electrode active material is w １ Therefore, 0.1 < w １ The positive electrode plate according to claim 1, characterized in that the content is <3% and the particle size of the first component is 50 nm to 500 nm.

7. The mass ratio of the second component to the cathode active material is w ２ Therefore, 0 ≤ w ２ The positive electrode plate according to claim 2, characterized in that the second component is <5% and the particle size of the second component is 10 nm to 10 μm.

8. The mass ratio of the second component to the cathode active material is w ２ Therefore, 0 ≤ w ２ The positive electrode plate according to claim 2, characterized in that the second component is <3% and the particle size of the second component is 50 nm to 500 nm.

9. Step 1 involves uniformly mixing the first component or a mixture of the first and second components, a positive electrode active material, a conductive additive, a binder, and a solvent to form a slurry. Step 2 involves applying the slurry obtained in Step 1 to the surface of the aluminum current collector to form a positive electrode plate. Step 3 involves blow-drying and vacuum-drying the positive electrode plate obtained in Step 2 to obtain the final positive electrode plate. The second component is LiM2 ２ (PO ４ ) ３ Li １＋ｘ２ Al ｘ２ M2 ２－ｘ２ (PO ４ ) ３ M2O ２ Li １６－４ｙ２ M2 ｙ２ O ８ M2P ２ O ７ M3PO ４ M3 ２ SiO ５ , M4 ３ (PO ４ ) ２ , M4 ２ SiO ４ A method for manufacturing a positive electrode plate for a liquid lithium battery or a mixed solid-liquid lithium battery according to any one of claims 1 to 8, characterized in that at least one or more combinations selected from, where M2 is one selected from Ti, Ge, Zr, and Hf, where 0 < x2 < 0.6, and M3 and M4 are one selected from Al, Ga, Sc, Y, Ca, Sr, Zn, Si, In, Lu, La, Fe, Cr, and Ge, where 3 < y2 < 4.

10. A lithium battery cell comprising a positive electrode plate, a negative electrode plate, a separator, an electrolyte, and a case, wherein the positive electrode plate is the positive electrode plate described in any one of claims 1 to 8.

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