High-performance cathode material, method for preparing the same, and its application

Abstract

The objective is to provide high-performance cathode materials, methods for preparing them, and their applications. [Solution] The positive electrode material comprises a porous material, a lithium-containing compound, metal nanoparticles, and a positive electrode active material. The lithium-containing compound comprises an inorganic lithium source material and / or an organic lithium source material. The metal nanoparticles comprise one or more of Al, Ti, Mn, Co, Ni, Cu, Zn, Zr, Mo, Ge, and Sn. During the first charge-discharge cycle of the lithium battery, the reactive sites on the metal surface of the metal nanoparticles adsorb the inert lithium-containing compound, thereby deforming or breaking the chemical bonds in the lithium-containing material, which then act as a catalyst for the lithium-containing compound. The catalytic effect is further enhanced by the active centers of the electrocatalytic reaction provided by the specific surface area of ​​the metal nanoparticles. These factors work together to completely decompose the lithium-containing compound and release lithium ions, thereby improving the energy density and safety of the lithium battery.

Description

[Technical Field]

[0001] (cross reference) This application claims priority to the Chinese patent application filed with the China National Intellectual Property Office on April 19, 2023, with application number 202310426149.5, and titled "High-performance cathode material, method for preparing the same, and applications."

[0002] (Technical field) This invention relates to the technical field of lithium battery materials, and more particularly to high-performance cathode materials, methods for preparing the same, and applications. [Background technology]

[0003] In China, as green and low-carbon industries develop rapidly, the adoption rate of new energy vehicles is increasing day by day, and the demand for energy storage batteries is also surging. Among these, lithium batteries have advantages such as high operating voltage, large specific capacity, high energy density, no memory effect, long cycle life, and environmental friendliness, making them the main choice for rechargeable power sources in current portable electronic products and new energy vehicles.

[0004] To meet current development needs, electrode materials with high energy density and high specific capacity have become a top priority for battery companies. Silicon-based materials for anodes, due to their abundant reserves and extremely high theoretical specific capacity, have become a top choice for battery companies and are one of the materials with the most potential as anode materials for next-generation lithium-ion batteries.

[0005] However, when using a silicon anode, the problem of low initial Coulombic efficiency becomes relatively pronounced. Due to the large volume expansion of silicon, the solid electrolyte interface (SEI) film on the silicon surface is constantly undergoing a dynamic "breakdown-regrowth" process. This ultimately leads to a continuous increase in the thickness of the SEI film, resulting in high interfacial impedance, consumption of active material, and a decrease in capacity and initial Coulombic efficiency. Therefore, to ensure battery capacity, it is necessary to replenish lost lithium and extend the cycle life of the lithium battery.

[0006] Currently, most companies employ lithium replenishment technology for negative electrodes. Methods include simple and effective approaches such as pre-lithiation of silicon-based negative electrode materials with metallic lithium powder, electrochemical pre-lithiation, and direct contact short-circuiting. However, these methods have high environmental requirements, such as oxygen-free, anhydrous, and dry environments. The lithium replenishment process using metallic lithium has particularly high production environment requirements, necessitating a closed-loop slurry mixing system, resulting in high costs, which poses a challenge for large-scale applications.

[0007] Therefore, major battery companies and battery material companies are actively seeking technological breakthroughs to safely, inexpensively, and easily replenish lithium in order to achieve improvements in overall battery capacity and cycle life. [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] The object of the present invention is to provide a high-performance cathode material, a method for preparing the same, and its applications. By utilizing doped nanometal elements, lithium-containing compounds that are inert at room temperature are catalyzed during the charge-discharge process to completely decompose the lithium-containing compounds and release lithium ions, thereby improving the energy density of the battery. At the same time, the gas generated from the completely catalytically decomposed lithium-containing compounds is also discharged during the battery formation process, thus avoiding the gas generation problem of batteries during normal use and improving battery safety. Furthermore, both the doped metal elements and porous materials can accelerate the internal conduction rate of lithium ions and improve the conductivity of the cathode material, ultimately achieving the objective of improving the overall capacity and cycle life of the battery through a safe, low-cost, and simple process. [Means for solving the problem]

[0009] Therefore, in a first embodiment, an embodiment of the present invention provides a high-performance cathode material, which is used in a lithium battery, and which comprises a porous material, a lithium-containing compound, metal nanoparticles, and a cathode active material. The lithium-containing compound comprises an inorganic lithium source material and / or an organic lithium source material, wherein the inorganic lithium source material comprises one or more of lithium carbonate, lithium oxide, lithium phosphate, lithium manganate, lithium hydroxide, or lithium iodide, and the organic lithium source material comprises one or more of butyllithium, phenyllithium, cyclopentadienide lithium, or lithium acetate. The aforementioned metal nanoparticles include one or more elements and / or alloys of Al, Ti, Mn, Co, Ni, Cu, Zn, Zr, Mo, Ge, and Sn, with a particle size D v100 ≤500nm, During the initial charge-discharge cycle of a lithium battery, reactive sites on the metal surface of metal nanoparticles adsorb inert lithium-containing compounds, deforming or breaking chemical bonds in the lithium-containing material, thereby catalyzing the lithium-containing compounds. The catalytic effect is further enhanced by the active centers of the electrocatalytic reaction provided by the specific surface area of ​​the metal nanoparticles. These factors work together to promote the complete decomposition of the lithium-containing compounds and the release of lithium ions, thereby improving the energy density and safety of the lithium battery.

[0010] Preferably, the average particle size D of the porous material. v50 The particle size is 100 nm to 100 μm, the pore diameter is 1 nm to 500 nm, and the porosity is 30% to 95%. Particle size D of the lithium-containing compound particles 50 The range is 0.5 nm to 10 μm. Particle size D of the particles of the positive electrode active material v50 The size is 5-20 μm.

[0011] Preferably, the porous material comprises one or more of porous carbon, graphene microspheres, single-walled carbon nanotubes, and multi-walled carbon nanotubes. The positive electrode active material includes one or more of the following: lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate, lithium nickel cobalt manganese oxide, or lithium nickel cobalt aluminate.

[0012] Preferably, the mass of the positive electrode active material accounts for 80% to 99.9% of the total mass of the positive electrode material. The total mass of the porous material, lithium-containing compound, and metal nanoparticles accounts for 0.1% to 20% of the total mass of the cathode material.

[0013] Preferably, the mass of the positive electrode active material accounts for 70% to 94% of the total mass of the positive electrode material. The total mass of the porous material, lithium-containing compound, and metal nanoparticles accounts for 6% to 30% of the total mass of the cathode material. Here, the mass of the porous material accounts for 0.5% to 15% of the total mass of the cathode material, the mass of the metal nanoparticles accounts for 0.5% to 10% of the total mass of the cathode material, and the mass of the lithium-containing compound accounts for 5% to 20% of the total mass of the cathode material.

[0014] In a second embodiment, an embodiment of the present invention provides a method for preparing a high-performance cathode material as described in the first embodiment, wherein the preparation method is a liquid-phase method. A premixed solution is obtained by uniformly dispersing metal nanoparticles and a lithium-containing compound in an organic solvent. A mixed solution is obtained by adding the porous material to the premixed solution and dispersing it thoroughly and uniformly for 2 to 10 hours. The aforementioned mixed solution is placed in a high-temperature furnace, heated to 600°C to 1000°C under an inert atmosphere, and the temperature is maintained for 2 to 10 hours. After removing the material, it is pulverized and sieved to obtain a precursor material. The method includes placing the precursor material and the cathode active material into a mixing apparatus and mixing them for 0.5 to 5 hours to obtain a high-performance cathode material after uniform mixing.

[0015] Preferably, the organic solvent contains one or more of toluene, isopropanol, absolute ethanol, dimethylformamide, acetone, ethylene glycol dimethyl ether, or tetrahydrofuran.

[0016] Preferably, the mixing device includes one or more of a stirrer, a disperser, a ball mill device, or an ultrasonic machine, The heating furnace includes one or more of a box-type heating furnace, a tubular heating furnace, or a rotary furnace.

[0017] In a third aspect, an embodiment of the present invention provides a positive electrode plate including the high-performance positive electrode material described in the first aspect.

[0018] In a fourth aspect, an embodiment of the present invention provides a lithium-ion battery including the positive electrode plate described in the third aspect.

Advantages of the Invention

[0019] The high-performance positive electrode material provided in the embodiments of the present invention utilizes a doped nano metal element to catalyze a lithium-containing compound that is inert at room temperature during the charge and discharge process, completely decomposes the lithium-containing compound to release lithium ions, thereby improving the energy density of the battery. At the same time, the gas generated from the completely catalytically decomposed lithium-containing compound is also discharged during the battery formation process, thus avoiding the gas generation problem of the battery during normal use and improving the safety of the battery. Moreover, both the doped metal element and the porous material can accelerate the internal conduction rate of lithium ions and improve the conductivity of the positive electrode material, ultimately achieving the goal of improving the capacity and cycle life of the entire battery with a safe, low-cost, and simple process.

Brief Description of the Drawings

[0020] [Figure 1] It is a flowchart of a method for preparing a high-performance positive electrode material according to an embodiment of the present invention. [Figure 2]These are cycle curve diagrams for a battery assembled using the high-performance cathode material prepared in Example 1 of the present invention and a battery assembled using the cathode material prepared in Comparative Example 2. [Modes for carrying out the invention]

[0021] The present invention will be described in detail below with reference to the drawings and specific embodiments, but these embodiments are merely for the purpose of explaining the present invention in more detail and should be understood as not intended to limit the present invention in any way, that is, they are not intended to limit the scope of protection of the present invention.

[0022] The embodiments of the present invention provide a high-performance cathode material comprising a porous material, a lithium-containing compound, metal nanoparticles, and a cathode active material.

[0023] The lithium-containing compound comprises an inorganic lithium source material and / or an organic lithium source material, wherein the inorganic lithium source material comprises one or more of lithium carbonate, lithium oxide, lithium phosphate, lithium manganate, lithium hydroxide, or lithium iodide, and the organic lithium source material comprises one or more of butyllithium, phenyllithium, cyclopentadienide lithium, or lithium acetate. Particle size D of the lithium-containing compound 50 The range is 0.5 nm to 10 μm.

[0024] Metal nanoparticles contain one or more elements and / or alloys of Al, Ti, Mn, Co, Ni, Cu, Zn, Zr, Mo, Ge, and Sn, with a particle size D v100 The range is ≤500nm.

[0025] During the initial charge-discharge cycle of a lithium battery, reactive sites on the metal surface of metal nanoparticles adsorb inert lithium-containing compounds. This deforms or breaks chemical bonds in the lithium-containing material, catalyzing the lithium-containing compounds and promoting their decomposition and release of lithium ions, thereby improving the initial cycle efficiency of the lithium battery.

[0026] The porous material contains one or more of the following: porous carbon, graphene microspheres, single-walled carbon nanotubes, and multi-walled carbon nanotubes, with an average particle size D v50 The surface area is 100 nm to 100 μm, the pore size is 1 nm to 500 nm, and the porosity is 30% to 95%.

[0027] The positive electrode active material contains one or more of the following: lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate, nickel cobalt manganese oxide, or nickel cobalt aluminate, and the particle size D of the positive electrode active material particles v50 The size is 5-20 μm.

[0028] In the above materials, the total mass of the porous material, lithium-containing compound, and metal nanoparticles accounts for 0.1% to 20% of the total mass of the cathode material, and the mass of the cathode active material accounts for 80% to 99.9% of the total mass of the cathode material.

[0029] Preferably, the total mass of the porous material, lithium-containing compound, and metal nanoparticles accounts for 6% to 30% of the total mass of the cathode material, and the mass of the cathode active material accounts for 70% to 94% of the total mass of the cathode material. In this preferred scheme, the mass of the porous material accounts for 0.5% to 15% of the total mass of the cathode material, the mass of the metal nanoparticles accounts for 0.5% to 10% of the total mass of the cathode material, and the mass of the lithium-containing compound accounts for 5% to 20% of the total mass of the cathode material.

[0030] More preferably, the mass of the porous material accounts for 0.5% to 15% of the total mass of the cathode material, the mass of the metal nanoparticles accounts for 2% to 8% of the total mass of the cathode material, and the mass of the lithium-containing compound accounts for 7% to 15% of the total mass of the cathode material.

[0031] During the initial charge-discharge cycle of a lithium battery, elemental and / or alloy metal elements can act as catalysts for lithium-containing compounds, promoting their decomposition and release of lithium ions, thereby improving the initial cycle efficiency of the lithium battery. This is because the elemental and / or alloy metal elements used in this invention are transition metal elements. In each metal element except Cu, the d orbital of the second shell from the outermost shell is not filled, i.e., it has a d vacancy. In the case of Cu, due to the charging and discharging action of the battery, the adjacent S orbital is not filled with electrons, so d electrons transition to the S orbital to form a d vacancy. On the surface of transition metal elements, active sites are usually associated with d orbitals and d vacancies where d electrons are densely packed. These d orbitals and d vacancies can form coordinate bonds that chemically bond with functional groups within the molecule, thereby assisting reactions and exhibiting strong catalytic activity. d% is usually used to indicate the percentage of d electrons of transition metal atoms in a compound or material, and d% has a significant impact on the reaction activity and adsorption capacity of the metal surface. This is because the reactive activity of a metal surface is closely related to the electronic structure on the metal surface. On the other hand, on a metal surface, d electrons are closer to the surface than other electrons and are more susceptible to the influence of external substances, thus more likely to participate in chemical reactions. Therefore, the more d electrons there are on a metal surface, the stronger the reactive activity of the metal surface tends to be. On the other hand, d electrons can also affect chemiadsorption on a metal surface. d vacancies on a transition metal surface can form coordination bonds with other d vacancies, making the adsorption of molecules on the surface easier. Therefore, the number of d vacancies can also affect the adsorption capacity of molecules on the metal surface. Thus, during the initial charge-discharge process, the active sites on the surface of the metal element are used to catalyze the release of lithium ions in lithium-containing compounds.

[0032] Under the initial charge-discharge voltage, the reactive sites on the metal surface can adsorb the lithium-containing compound, which is itself inert, causing deformation or cleavage of the chemical bonds in the lithium-containing compound. This accelerates charge transport between the catalyst (metal) and the adsorbent (lithium-containing compound). Furthermore, the large specific surface area of ​​the nanoparticles allows for the presence of numerous active centers for electrocatalytic reactions, significantly improving the catalytic effect. This enables the activation of the lithium-containing compound and the complete dissociation of active lithium ions.

[0033] The high-performance cathode material of the above embodiment of the present invention can be prepared by the liquid-phase method shown in Figure 1.

[0034] In step 110, a premixed solution is obtained by uniformly dispersing metal nanoparticles and a lithium-containing compound in an organic solvent.

[0035] In this step, the organic solvent includes one or more of toluene, isopropanol, anhydrous ethanol, dimethylformamide, acetone, ethylene glycol dimethyl ether, or tetrahydrofuran.

[0036] In step 120, the porous material is added to the premixed solution and dispersed thoroughly and uniformly for 2 to 10 hours to obtain a mixed solution.

[0037] In step 130, the mixed solution is placed in a high-temperature furnace, heated to 600°C to 1000°C under an inert atmosphere, and the temperature is maintained for 2 to 10 hours. After removing the material, it is pulverized and sieved to obtain the precursor material.

[0038] The heating furnace includes one or more types from box-type heating furnaces, tubular heating furnaces, and rotary furnaces.

[0039] In step 140, the precursor material and the cathode active material are placed in a mixing device and mixed for 0.5 to 5 hours to obtain a high-performance cathode material after uniform mixing.

[0040] The mixing device includes one or more of a stirrer, a disperser, a ball mill device, and an ultrasonic device.

[0041] The high-performance cathode material of the embodiment of the present invention is used as a cathode active material for a cathode plate, and the cathode plate is applicable to a lithium battery.

[0042] To better understand the technical solution according to the present invention, the preparation process and characteristics of the high-performance cathode material of the present invention will be described below by way of a plurality of specific examples.

[0043] [Example 1] This example provides a preparation process and a characteristic test for a high-performance cathode material. The specific preparation process is as follows.

[0044] 1) 20 g of metallic copper powder and 50 g of lithium carbonate are added to an anhydrous ethanol solution, put into a disperser and dispersed. The rotation speed of the disperser is set to 1500 r / min, and stirred and dispersed sufficiently for 8 hours at room temperature to obtain a premixed solution. Here, the D v100 of the metallic copper powder is 205 nm.

[0045] 2) 15 g of porous carbon is added to the above premixed solution, and continuously and uniformly dispersed in the disperser. The rotation speed of the disperser is set to 2000 r / min, and stirred continuously for 8 hours at room temperature to obtain a mixed solution.

[0046] 3) The mixed solution is put into a box-type heating furnace, heated to 800 °C under an argon atmosphere, kept at the temperature for 6 hours, taken out the material, pulverized, and sieved to obtain a precursor material.

[0047] 4) 2 Kg of lithium iron phosphate and the precursor material are continuously and uniformly dispersed in the disperser. The rotation speed of the disperser is set to 1300 r / min, and stirred continuously for 3 hours at room temperature to obtain a high-performance cathode material.

[0048] A cathode plate is fabricated using the high-performance cathode material prepared in this example, and a button-type half-cell and a full-cell are assembled for testing.

[0049] In the fabrication and testing of button-type half-cells, the obtained high-performance cathode material, the conductive additive carbon black, and the adhesive polyvinylidene fluoride (PVDF) were weighed in a mass ratio of 96%:2%:2%. A slurry was prepared using a beater, then applied, dried, and cut, and assembled into a battery by combining it with lithium foil in a glove box. Constant current charge-discharge mode tests were performed using a charge / discharge device, with a discharge termination voltage of 2.5V and a charge termination voltage of 3.65V. The initial charge-discharge test was performed at a current density of 0.1C. Table 1 shows the test data for the initial Coulomb efficiency and reversible capacity of the button cell.

[0050] [Method for preparing and testing full cells] In preparing the negative electrode plate, a silicon-oxygen negative electrode material containing a carbon coating layer and graphite were mixed into a composite with a specific volume of 450 mAg / h. This composite, carbon black as a conductive additive, and polyvinylidene fluoride (PVDF) as an adhesive were weighed and mixed in a ratio of 95%:2%:3%. The mixed materials and solvent were placed in a beater at room temperature to prepare a slurry. The prepared slurry was uniformly applied onto copper foil, the coating speed was set to 2.2 m / min to 3.5 m / min, and the coating machine drying tunnel temperature was set to 70 to 100°C. After drying both sides in the coating machine, a negative electrode plate was obtained.

[0051] In preparing the positive electrode plate, high-performance positive electrode material, conductive additive, and adhesive were weighed and mixed in a ratio of 96%:2%:2%. The mixed materials and the solvent, N-methylpyrrolidone, were placed in a beater at room temperature to prepare a slurry. The prepared slurry was uniformly applied to aluminum foil, the application speed was set to 2.0 m / min to 3.0 m / min, and the coating machine drying tunnel temperature was set to 90 to 120°C. The slurry was applied to both sides of the foil using the coating machine and dried to obtain the positive electrode plate.

[0052] In the fabrication of the battery, an aluminum tab was used as an exposed tab for the positive electrode of the positive electrode plate, and a nickel-plated copper tab was used as an exposed tab for the negative electrode of the negative electrode plate. The fabricated positive and negative electrode plates, along with a separator, were wound up to create a bare cell. Next, the cell was encapsulated using an aluminum plastic film through a heat sealing process, and moisture inside the battery was removed by baking under high temperature and vacuum. Then, 1 mole of electrolyte, which is a mixed solution of LiPF6 and ethylene carbonate / dimethyl carbonate (EC / DMC), was injected to create the cell. After vacuum sealing, a full cell was obtained.

[0053] In the test, constant current charge-discharge mode tests were performed on the fabricated full cells using a charger / discharger. The discharge termination voltage was 2.5V, the charge termination voltage was 3.65V, and all discharge tests after the first cycle were performed at a current density of 1C.

[0054] Table 1 shows the test results for the initial Coulomb efficiency, 0.1C reversible capacity, and capacity retention rate after 300 and 600 cycles at a 1C rate for the full cell manufactured in this embodiment.

[0055] [Example 2] This embodiment demonstrates the preparation process and characteristic testing of a high-performance cathode material. The specific preparation process is as follows:

[0056] 1) Add 13 g of aluminum powder and 68 g of lithium oxide to an isopropanol solution, place in a ball mill, set the rotation speed to 1000 r / min, rotate in both forward and reverse directions, and perform ball milling at room temperature for 10 hours to mix and obtain a premixed solution. Here, the D of the aluminum powder v100 It is 228nm.

[0057] 2) Add 24 g of single-walled carbon nanotubes to the above premixed solution and continue to disperse them uniformly in a ball mill apparatus. Set the rotation speed of the ball mill apparatus to 1600 r / min and continue stirring at room temperature for 8 hours to obtain a mixed solution.

[0058] 3) The mixed solution is placed in a rotary furnace, heated to 700°C under an argon atmosphere, and the temperature is maintained for 8 hours. After removing the material, it is pulverized and sieved to obtain the precursor material.

[0059] 4) The lithium iron phosphate 2 kg and the precursor material are further uniformly dispersed in a ball mill apparatus, and the rotation speed is set to 800 r / min. The mixture is stirred continuously at room temperature for 2.5 hours to obtain a high-performance cathode material.

[0060] Using the high-performance cathode material prepared in this embodiment, cathode plates were fabricated, and button-type half-cells and full-cells were assembled and tested. The specific process was the same as in Example 1. The test data is shown in Table 1.

[0061] [Example 3] This embodiment demonstrates the preparation process and characteristic testing of a high-performance cathode material. The specific preparation process is as follows:

[0062] 1) Add 37g of zinc powder and 137g of lithium phosphate to a toluene solution, place in an ultrasonic machine, set the ultrasonic frequency to 50KHz, and sonicate agitation for 9 hours to obtain a premixed solution. Here, the zinc powder D v100 It is 138 nm.

[0063] 2) Add 56 g of multi-walled carbon nanotubes to the above premixed solution and continue stirring in an ultrasonic device. Set the ultrasonic frequency to 70 kHz and stir ultrasonically for 3 hours to obtain a mixed solution.

[0064] 3) The mixed solution is placed in a rotary furnace, heated to 900°C under an argon atmosphere, and the temperature is maintained for 3 hours. After removing the material, it is pulverized and sieved to obtain the precursor material.

[0065] 4) The lithium iron phosphate (2 kg) and precursor material are uniformly dispersed in an ultrasonic device, the ultrasonic frequency is set to 70 kHz, and the mixture is stirred continuously at room temperature for 2 hours to obtain a high-performance cathode material.

[0066] Using the high-performance cathode material prepared in this embodiment, cathode plates were fabricated, and button-type half-cells and full-cells were assembled and tested. The specific process was the same as in Example 1. The test data is shown in Table 1.

[0067] [Example 4] This embodiment demonstrates the preparation process and characteristic testing of a high-performance cathode material. The specific preparation process is as follows:

[0068] 1) Add 42g of metallic molybdenum powder and 245g of lithium manganate to an ethylene glycol dimethyl ether solution, place in a ball mill, set the rotation speed to 2000 r / min, rotate in both forward and reverse directions, and perform ball milling at room temperature for 5 hours to mix and obtain a premixed solution. Here, the D of the metallic molybdenum powder is obtained. v100 This corresponds to 286 nm.

[0069] 2) Add 38 g of graphene microspheres to the above premixed solution and continue to disperse them uniformly in a ball mill apparatus. Set the rotation speed of the ball mill apparatus to 1300 r / min and continue stirring at room temperature for 10 hours to obtain a mixed solution.

[0070] 3) The mixed solution is placed in a rotary furnace, heated to 750°C under an argon atmosphere, and the temperature is maintained for 5 hours. After removing the material, it is pulverized and sieved to obtain the precursor material.

[0071] 4) The lithium iron phosphate (2 kg) and precursor material are further uniformly dispersed in a ball mill apparatus, and the rotation speed is set to 600 r / min. The mixture is stirred continuously at room temperature for 4 hours to obtain a high-performance cathode material.

[0072] Using the high-performance cathode material prepared in this embodiment, cathode plates were fabricated, and button-type half-cells and full-cells were assembled and tested. The specific process was the same as in Example 1. The test data is shown in Table 1.

[0073] [Example 5] This embodiment demonstrates the preparation process and characteristic testing of a high-performance cathode material. The specific preparation process is as follows:

[0074] 1) Add 60 g of aluminum-nickel alloy powder and 210 g of lithium hydroxide to a tetrahydrofuran solution, place in a disperser and disperse, set the disperser's rotation speed to 1100 r / min, and stir thoroughly at room temperature for 3.5 hours to obtain a premixed solution, where the aluminum-nickel alloy powder D v100 It is 85nm.

[0075] 2) Add 50 g of single-walled carbon nanotubes to the above premixed solution and continue to disperse them uniformly in the disperser. Set the rotation speed of the disperser to 1390 r / min and continue stirring at room temperature for 7 hours to obtain the mixed solution.

[0076] 3) The mixed solution is placed in a tubular heating furnace, heated to 860°C under an argon atmosphere, and the temperature is maintained for 3.5 hours. After removing the material, it is pulverized and sieved to obtain the precursor material.

[0077] 4) The lithium iron phosphate (2 kg) and precursor material are further uniformly dispersed in the disperser, and the disperser's rotation speed is set to 900 r / min. The mixture is stirred continuously at room temperature for 0.5 hours to obtain a high-performance cathode material.

[0078] Using the high-performance cathode material prepared in this embodiment, cathode plates were fabricated, and button-type half-cells and full-cells were assembled and tested. The specific process was the same as in Example 1. The test data is shown in Table 1.

[0079] [Example 6] This embodiment demonstrates the preparation process and characteristic testing of a high-performance cathode material. The specific preparation process is as follows:

[0080] 1) Add 37g of tin powder and 359g of butyllithium to a dimethylformamide solution, place in an ultrasonic machine, set the ultrasonic frequency to 40KHz, and sonicate agitation for 5 hours to obtain a premixed solution, where the tin powder D v100 It is 53nm.

[0081] 2) Add 206 g of porous carbon to the above premixed solution, continue stirring in an ultrasonic machine, set the ultrasonic frequency to 80 kHz, and ultrasonic stirring for 10 hours to obtain a mixed solution.

[0082] 3) The mixed solution is placed in a rotary furnace, heated to 1000°C under an argon atmosphere, and the temperature is maintained for 2 hours. After removing the material, it is pulverized and sieved to obtain the precursor material.

[0083] 4) The lithium iron phosphate (2 kg) and precursor material are uniformly dispersed in an ultrasonic device, the ultrasonic frequency is set to 40 kHz, and the mixture is stirred continuously at room temperature for 4 hours to obtain a high-performance cathode material.

[0084] Using the high-performance cathode material prepared in this embodiment, cathode plates were fabricated, and button-type half-cells and full-cells were assembled and tested. The specific process was the same as in Example 1. The test data is shown in Table 1.

[0085] [Example 7] This embodiment demonstrates the preparation process and characteristic testing of a high-performance cathode material. The specific preparation process is as follows:

[0086] 1) D v100 40 g of 39 nm copper-tin alloy powder and 457 g of lithium acetate are added to an ethylene glycol dimethyl ether solution, placed in a disperser, and dispersed. The disperser's rotation speed is set to 1400 r / min, and the mixture is stirred thoroughly at room temperature for 2 hours to obtain a premixed solution.

[0087] 2) Add 170 g of graphene microspheres to the above premixed solution and continue to disperse them uniformly in the disperser. Set the rotation speed of the disperser to 2000 r / min and continue stirring at room temperature for 2 hours to obtain the mixed solution.

[0088] 3) The mixed solution is placed in a tubular heating furnace, heated to 950°C under an argon atmosphere, and the temperature is maintained for 4.5 hours. After removing the material, it is pulverized and sieved to obtain the precursor material.

[0089] 4) The lithium iron phosphate (2 kg) and the precursor material are further uniformly dispersed in the disperser, and the disperser's rotation speed is set to 700 r / min. The mixture is stirred continuously at room temperature for 5 hours to obtain a high-performance cathode material.

[0090] Using the high-performance cathode material prepared in this embodiment, cathode plates were fabricated, and button-type half-cells and full-cells were assembled and tested. The specific process was the same as in Example 1. The test data is shown in Table 1.

[0091] [Comparative Example 1] In this comparative example, lithium iron phosphate, the same cathode material as in the example, was used to fabricate the cathode plate, and button-type half-cells and full-cells were assembled and tested. The specific process was the same as in Example 1. The test data is shown in Table 1.

[0092] [Comparative Example 2] This comparative example illustrates the preparation process and characterization testing of a cathode material that is not doped with metal elements but has lithium added. The specific preparation process is as follows:

[0093] 1) Add 210 g of lithium hydroxide to the tetrahydrofuran solution, place in a disperser and disperse. Set the disperser's rotation speed to 1100 r / min and stir thoroughly at room temperature for 3.5 hours to obtain a premixed solution.

[0094] 2) Add 50 g of single-walled carbon nanotubes to the above premixed solution and continue to disperse them uniformly in the disperser. Set the rotation speed of the disperser to 1390 r / min and continue stirring at room temperature for 7 hours to obtain the mixed solution.

[0095] 3) The mixed solution is placed in a tubular heating furnace, heated to 860°C under an argon atmosphere, and the temperature is maintained for 3.5 hours. After removing the material, it is pulverized and sieved to obtain the precursor material.

[0096] 4) The lithium iron phosphate and precursor material are further uniformly dispersed in a disperser, and the disperser's rotation speed is set to 900 r / min. By continuing to stir at room temperature for 0.5 hours, a cathode material is obtained in which lithium is added but no metal elements are doped.

[0097] In this comparative example, a positive electrode plate was fabricated using the lithium-doped positive electrode material, which was not doped with metal elements. Button-type half-cells and full-cells were assembled and tested, with the specific process being the same as in Example 1. The test data is shown in Table 1. Figure 2 shows the cycle curves of a battery assembled using the high-performance positive electrode material prepared in Example 1 of the present invention and a battery assembled using the positive electrode material prepared in Comparative Example 2.

[0098] For the positive electrode materials in Examples 1-7 and Comparative Examples 1-2, the initial Coulomb efficiency, reversible capacity, and capacity retention rate of the full cell after 300 and 600 cycles were measured for each button cell, and the results are shown in Table 1.

[0099] [Table 1]

[0100] As can be seen from the comparison of test data in Table 1, under the same test conditions, the charge ratio capacity in the first cycle and the capacity retention rate after the cycle of the cathode materials prepared in Examples 1 to 7 are both much higher than those of the cathode materials in Comparative Examples 1 to 2. The reason is that in Examples 1 to 7, porous materials are used as a framework, and metal elements and elemental lithium are dispersed in the pores of the porous framework material. Doped nanometal elements are used to catalyze lithium-containing compounds that are inert at room temperature during the charging process, completely decomposing the lithium-containing compounds and releasing lithium ions. This increases the lithium desorption capacity of the cathode material and improves the energy density of the battery. At the same time, the gas generated from the completely catalytically decomposed lithium-containing compounds is also discharged during the battery formation process, thus avoiding the problem of gas generation due to the continuous decomposition of lithium-containing compounds during normal use of the battery and improving battery safety. Furthermore, both the doped metal elements and porous materials can accelerate the internal conduction rate of lithium ions and improve the conductivity of the cathode material, ultimately achieving the objective of improving the overall capacity and cycle life of the battery through a safe, low-cost, and simple process.

[0101] The specific embodiments described above further elaborate on the objectives, technical proposals, and beneficial effects of the present invention. It should be understood that these are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

[0102] (Note) (Note 1) A high-performance cathode material, wherein the cathode material is used in a lithium battery, and the cathode material comprises a porous material, a lithium-containing compound, metal nanoparticles, and a cathode active material. The lithium-containing compound comprises an inorganic lithium source material and / or an organic lithium source material, wherein the inorganic lithium source material comprises one or more of lithium carbonate, lithium oxide, lithium phosphate, lithium manganate, lithium hydroxide, or lithium iodide, and the organic lithium source material comprises one or more of butyllithium, phenyllithium, cyclopentadienide lithium, or lithium acetate. The aforementioned metal nanoparticles include one or more elements and / or alloys of Al, Ti, Mn, Co, Ni, Cu, Zn, Zr, Mo, Ge, and Sn, with a particle size D v100 ≤500nm, During the initial charge-discharge cycle of a lithium battery, the reactive sites on the metal surface of metal nanoparticles adsorb inert lithium-containing compounds, deforming or breaking chemical bonds in the lithium-containing material, thereby exhibiting catalytic activity on the lithium-containing compounds. Furthermore, the catalytic effect is enhanced by the active centers of the electrocatalytic reaction provided by the specific surface area of ​​the metal nanoparticles. These factors work together to promote the complete decomposition of the lithium-containing compounds and the release of lithium ions, thereby improving the energy density and safety of the lithium battery. A high-performance cathode material characterized by the following features.

[0103] (Note 2) The average particle size D of the porous material v50 The particle size is 100 nm to 100 μm, the pore diameter is 1 nm to 500 nm, and the porosity is 30% to 95%. Particle size D of the lithium-containing compound particles 50 The range is 0.5 nm to 10 μm. Particle size D of the particles of the positive electrode active material v50 The size is 5-20 μm. The high-performance cathode material described in Appendix 1, characterized by the features described herein.

[0104] (Note 3) The porous material comprises one or more of porous carbon, graphene microspheres, single-walled carbon nanotubes, and multi-walled carbon nanotubes. The positive electrode active material includes one or more of the following: lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate, lithium nickel cobalt manganese oxide, or lithium nickel cobalt aluminate. The high-performance cathode material described in Appendix 1, characterized by the features described herein.

[0105] (Note 4) The mass of the positive electrode active material accounts for 80% to 99.9% of the total mass of the positive electrode material. The total mass of the porous material, lithium-containing compound, and metal nanoparticles accounts for 0.1% to 20% of the total mass of the positive electrode material. The high-performance cathode material described in Appendix 1, characterized by the features described herein.

[0106] (Note 5) The mass of the positive electrode active material accounts for 70% to 94% of the total mass of the positive electrode material. The total mass of the porous material, lithium-containing compound, and metal nanoparticles accounts for 6% to 30% of the total mass of the cathode material. Here, the mass of the porous material accounts for 0.5% to 15% of the total mass of the cathode material, the mass of the metal nanoparticles accounts for 0.5% to 10% of the total mass of the cathode material, and the mass of the lithium-containing compound accounts for 5% to 20% of the total mass of the cathode material. The high-performance cathode material described in Appendix 4, characterized by the features described herein.

[0107] (Note 6) A method for preparing a high-performance cathode material as described in any one of the above appendices 1 to 5, wherein the preparation method is a liquid-phase method. A premixed solution is obtained by uniformly dispersing metal nanoparticles and a lithium-containing compound in an organic solvent. A mixed solution is obtained by adding the porous material to the premixed solution and dispersing it thoroughly and uniformly for 2 to 10 hours. The aforementioned mixed solution is placed in a high-temperature furnace, heated to 600°C to 1000°C under an inert atmosphere, and the temperature is maintained for 2 to 10 hours. After removing the material, it is pulverized and sieved to obtain a precursor material. The precursor material and the cathode active material are placed in a mixing device and mixed for 0.5 to 5 hours to obtain a high-performance cathode material after uniform mixing. including, A preparation method characterized by the above.

[0108] (Note 7) The organic solvent includes one or more of toluene, isopropanol, anhydrous ethanol, dimethylformamide, acetone, ethylene glycol dimethyl ether, or tetrahydrofuran. The preparation method described in Appendix 6, characterized by the features described herein.

[0109] (Note 8) The mixing apparatus includes one or more of the following: a stirrer, a disperser, a ball mill, and an ultrasonic machine. The heating furnace includes one or more of the following: a box-type heating furnace, a tubular heating furnace, and a rotary furnace. The preparation method described in Appendix 6, characterized by the features described herein.

[0110] (Note 9) Includes a high-performance cathode material described in any one of the above appendices 1 to 5, A positive electrode plate characterized by the following features.

[0111] (Note 10) A lithium battery characterized by including the positive electrode plate described in Appendix 9 above.

Claims

1. A high-performance cathode material, wherein the cathode material is used in a lithium battery, and the cathode material comprises a porous material, a lithium-containing compound, metal nanoparticles, and a cathode active material. The lithium-containing compound comprises an inorganic lithium source material and / or an organic lithium source material, wherein the inorganic lithium source material comprises one or more of lithium carbonate, lithium oxide, lithium phosphate, lithium manganate, lithium hydroxide, or lithium iodide, and the organic lithium source material comprises one or more of butyllithium, phenyllithium, cyclopentadienide lithium, or lithium acetate. The metal nanoparticles include one or more elements and / or alloys from Al, Ti, Mn, Co, Ni, Cu, Zn, Zr, Mo, Ge, and Sn, with a particle size D ｖ１００ ≤500 nm, During the initial charge-discharge cycle of a lithium battery, the reactive sites on the metal surface of metal nanoparticles adsorb inert lithium-containing compounds, deforming or breaking chemical bonds in the lithium-containing material, thereby exhibiting catalytic activity on the lithium-containing compounds. Furthermore, the catalytic effect is enhanced by the active centers of the electrocatalytic reaction provided by the specific surface area of ​​the metal nanoparticles. These factors work together to promote the complete decomposition of the lithium-containing compounds and the release of lithium ions, thereby improving the energy density and safety of the lithium battery. A high-performance cathode material characterized by the following features.

2. The average particle size D of the porous material ｖ５０ The surface area is 100 nm to 100 μm, the pore size is 1 nm to 500 nm, and the porosity is 30% to 95%. Particle size D of the lithium-containing compound particles ５０ The size ranges from 0.5 nm to 10 μm. Particle size D of the particles of the positive electrode active material ｖ５０ The size is 5 to 20 μm. The high-performance cathode material according to feature 1.

3. The porous material comprises one or more of porous carbon, graphene microspheres, single-walled carbon nanotubes, and multi-walled carbon nanotubes. The positive electrode active material includes one or more of the following: lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate, nickel cobalt manganese oxide, or nickel cobalt aluminate. The high-performance cathode material according to feature 1.

4. The mass of the positive electrode active material accounts for 80% to 99.9% of the total mass of the positive electrode material. The total mass of the porous material, lithium-containing compound, and metal nanoparticles accounts for 0.1% to 20% of the total mass of the positive electrode material. The high-performance cathode material according to feature 1.

5. The mass of the positive electrode active material accounts for 70% to 94% of the total mass of the positive electrode material. The total mass of the porous material, lithium-containing compound, and metal nanoparticles accounts for 6% to 30% of the total mass of the cathode material. Here, the mass of the porous material accounts for 0.5% to 15% of the total mass of the cathode material, the mass of the metal nanoparticles accounts for 0.5% to 10% of the total mass of the cathode material, and the mass of the lithium-containing compound accounts for 5% to 20% of the total mass of the cathode material. The high-performance cathode material according to feature 4.

6. A method for preparing a high-performance cathode material according to any one of claims 1 to 5, wherein the preparation method is a liquid-phase method. A premixed solution is obtained by uniformly dispersing metal nanoparticles and a lithium-containing compound in an organic solvent. A mixed solution is obtained by adding the porous material to the premixed solution and dispersing it thoroughly and uniformly for 2 to 10 hours. The aforementioned mixed solution is placed in a high-temperature furnace, heated to 600°C to 1000°C under an inert atmosphere, and the temperature is maintained for 2 to 10 hours. After removing the material, it is pulverized and sieved to obtain a precursor material. The precursor material and the cathode active material are placed in a mixing device and mixed for 0.5 to 5 hours to obtain a high-performance cathode material after uniform mixing. including, A preparation method characterized by the above.

7. The organic solvent includes one or more of toluene, isopropanol, anhydrous ethanol, dimethylformamide, acetone, ethylene glycol dimethyl ether, or tetrahydrofuran. The preparation method according to feature 6.

8. The mixing apparatus includes one or more of the following: a stirrer, a disperser, a ball mill, and an ultrasonic machine. The heating furnace includes one or more of the following: a box-type heating furnace, a tubular heating furnace, and a rotary furnace. The preparation method according to feature 6.

9. The high-performance cathode material includes the one described in any one of claims 1 to 5 above. A positive electrode plate characterized by the following features.

10. A lithium battery characterized by including the positive electrode plate described in claim 9 above.

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