A quasi-solid-state lithium battery nickel-based ternary positive electrode material and its preparation method and application

Abstract

The present invention belongs to the technical field of lithium battery materials, and specifically relates to a quasi-solid-state lithium battery nickel-based ternary positive electrode material, its preparation method, and application. The quasi-solid-state lithium battery nickel-based ternary positive electrode material of the present invention has a double-layer spherical structure. The M metal in the inner layer of the nickel cobalt manganese oxide doped with the metal element M is evenly distributed, which changes the lattice characteristics of the original nickel cobalt manganese oxide; the outer layer is coated with a lithium salt sol, which can promote ion conduction and increase the interface contact between the active ingredients in the positive electrode material and the solid electrolyte. At the same time, the positive electrode material has high rate capacity performance, good structural stability, and low charge transfer impedance performance, which effectively improves the battery performance of the lithium battery. In addition, the preparation method is simple, the raw materials are cheap and easily available, and it is suitable for large-scale production.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithium battery materials. More specifically, it relates to a quasi-solid-state lithium battery nickel-based ternary cathode material, a preparation method, and applications thereof. Background Art

[0002] Quasi-solid-state lithium batteries are batteries containing a mixed solid-liquid electrolyte (where the liquid electrolyte accounts for 1-5% by mass). They offer the advantages of high energy density and the absence of persistent interfacial side reactions. They can improve the stability and safety issues of traditional lithium-ion batteries caused by lithium dendrites and corrosion of the cathode material. Solid electrolytes are a key component of solid-state lithium batteries, with oxide solid electrolytes being the most common. With their high chemical stability and low cost, they are considered one of the key materials for the widespread application of quasi-solid-state lithium-ion batteries. However, oxide solid electrolytes suffer from poor conductivity, poor compatibility between the electrolyte interface and the cathode active components, and high interfacial impedance. Nickel-based layered oxides, with their high surface activity and low synthesis cost, have been commercialized as cathode materials. However, as the nickel content of high-nickel layered oxides increases, the structural stability of the material decreases, and the cycling performance and specific capacity need to be further improved.

[0003] To address the above-mentioned problems, element doping is often used to change the lattice characteristics and ion valence of nickel-based ternary materials, thereby stabilizing the structure of nickel-based ternary materials and improving the cycle performance and specific capacity of lithium batteries. Lithium salt sol is used as a conductive buffer layer, lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) promotes ion conduction, and sodium carboxymethyl cellulose (CMC) increases solid / solid interface contact. For example, a Chinese patent application discloses a method for preparing a single crystal positive electrode material of nickel cobalt manganese oxide by doping with strontium. The method uses strontium salt to react with a ternary positive electrode material of nickel cobalt manganese oxide to prepare the material. Although the specific capacity and cycle performance of the prepared positive electrode material are improved to a certain extent, the problem of poor compatibility and large interface impedance between the electrolyte interface and the positive electrode active component is not solved. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the defects and shortcomings of the existing quasi-solid-state lithium battery nickel-based ternary positive electrode material, such as poor compatibility between the electrolyte interface and the positive electrode active components and large interface impedance, and to provide a quasi-solid-state lithium battery nickel-based ternary positive electrode material with good cycle stability, high specific capacity, good compatibility between the positive electrode active components and the electrolyte, and low impedance.

[0005] The purpose of the present invention is to provide a method for preparing a nickel-based ternary positive electrode material for a quasi-solid-state lithium battery.

[0006] Another object of the present invention is to provide a solid-state lithium battery positive electrode plate.

[0007] Another object of the present invention is to provide a quasi-solid-state lithium battery nickel-based ternary positive electrode material for use in lithium batteries.

[0008] The above purpose of the present invention is achieved through the following technical solutions:

[0009] A quasi-solid-state lithium battery nickel-based ternary positive electrode material, the quasi-solid-state lithium battery nickel-based ternary positive electrode material consists of an inner layer and an outer layer, the inner layer is a nickel cobalt manganese oxide doped with M metal element, the chemical formula is Li{Ni x Co y Mn 1-x-y O2}M z ; wherein 0.9≤x<1, 0≤y<0.1, x+y<1, 0.01≤z≤0.05, and M is at least one of Mg, Al, Zr, W, Y, Nb, Mo, In, and Ta elements; the outer layer is a lithium salt sol, which is composed of a lithium salt and a CMC hydrogel.

[0010] Preferably, the M is one or two of Mg, Zr, In, Nb or W.

[0011] Preferably, the molar amount of M accounts for 1 to 5 mol% of the entire M metal element-doped lithium nickel cobalt manganese oxide.

[0012] More preferably, the chemical formula of the element doping material is Li{Ni 0.9 Co 0.05 Mn 0.05 O2}Mg 0.02 、 Li{Ni 0.9 Co 0.05 Mn 0.05 O2}Zr 0.03 、Li{Ni 0.9 Co 0.05 Mn 0.05 O2}Zr 0.01 In 0.01 Or Li{Ni 0.9 Co 0.05 Mn 0.05 O2}Nb 0.02 W 0.01 .

[0013] Preferably, the CMC hydrogel is a mixture of CMC and ultrapure water with a concentration of 0.1 to 2 wt%.

[0014] Preferably, the lithium salt is lithium bis(trifluoromethanesulfonyl)imide (LiTFSI).

[0015] More preferably, the concentration of the lithium salt is 2 to 4 mol / L.

[0016] The present invention further provides a method for preparing a nickel-based ternary positive electrode material for a quasi-solid-state lithium battery, comprising the following steps:

[0017] S1: Mix and dissolve the nickel source, cobalt source, and manganese source in a solvent, adjust the pH to 10-12, filter after the reaction is complete, and post-treat the resulting solid to obtain powder A;

[0018] S2: The powder A obtained in step S1 is uniformly mixed with the metal salt M and a lithium source in an organic solvent, and pre-sintered by spray drying in an oxygen atmosphere at 400-400°C for 1-10 hours to obtain a mixture B, and then sintered once in an oxygen atmosphere at 700-950°C for 5-8 hours to obtain a mixture C;

[0019] S3: Mix the mixture C and the lithium salt sol evenly, and dry them to obtain a quasi-solid-state lithium battery nickel-based ternary positive electrode material.

[0020] More preferably, the nickel source includes nickel sulfate, nickel nitrate, and nickel acetate.

[0021] More preferably, the cobalt source includes cobalt sulfate, cobalt nitrate and cobalt acetate.

[0022] More preferably, the manganese source includes manganese sulfate, manganese nitrate and manganese acetate.

[0023] Preferably, in step S1, the molar ratio of the nickel source, the cobalt source and the manganese source is (0.9-0.95): (0.01-0.1): (0.01-0.1).

[0024] Preferably, in step S1, the solvent includes water and aqueous ammonia.

[0025] Preferably, in step S1, the pH is adjusted using aqueous ammonia, sodium hydroxide solution or potassium hydroxide solution.

[0026] Preferably, in step S1, the reaction temperature is 40-80°C.

[0027] Preferably, in step S1, the reaction time is 4 to 18 hours.

[0028] Preferably, in step S1, the reaction is carried out under stirring.

[0029] Preferably, in step S1, the post-processing includes washing and drying.

[0030] Preferably, in step S2, the molar ratio of the powder A, the metal salt M, and the lithium source is 1: (0.01-0.05): (1-1.2).

[0031] Preferably, in step S2, the M metal salt is at least one of magnesium ethoxide, aluminum ethoxide, zirconium ethoxide, tungsten ethoxide, yttrium acetate, niobium ethoxide, molybdenum ethoxide, indium ethoxide, and tantalum ethoxide.

[0032] Preferably, in step S2, the lithium source includes lithium carbonate or lithium nitrate.

[0033] Preferably, in step S2, the spray drying is performed in a spray dryer.

[0034] More preferably, the temperature at the inlet of the spray dryer is 500-400°C.

[0035] More preferably, the temperature at the outlet of the spray dryer is 400-450°C.

[0036] More preferably, the primary sintering is carried out in a tube furnace at a heating rate of 2-4° C. / min.

[0037] Preferably, in step S2, the oxygen volume concentration of the oxygen atmosphere is 95 to 99.999%.

[0038] Preferably, in step S2, the organic solvent includes one or both of ethanol and isopropanol.

[0039] Preferably, in step S3, the mass ratio of the mixture C to the lithium salt sol is 1:(0.05-0.2).

[0040] Preferably, in step S3, the drying includes vacuum drying.

[0041] More preferably, the vacuum drying temperature is 50-80° C., and the drying time is 1-12 hours.

[0042] The present invention further protects a solid-state lithium battery positive electrode plate, comprising the above-mentioned quasi-solid-state lithium battery nickel-based ternary positive electrode material.

[0043] The present invention further protects the application of the quasi-solid-state lithium battery nickel-based ternary positive electrode material in lithium batteries.

[0044] The present invention has the following beneficial effects:

[0045] The quasi-solid-state nickel-based ternary cathode material for lithium batteries of the present invention has a double-layer spherical structure. The inner layer of M metal-doped lithium nickel cobalt manganese oxide has a uniform distribution of M metal, which modifies the lattice properties of the original lithium nickel cobalt manganese oxide and enhances the bond energy between transition metal atoms and oxygen atoms. The outer layer is coated with a lithium salt sol, which promotes ion conduction and increases the active ingredients in the cathode material and the interfacial contact between the cathode material and the solid electrolyte. Furthermore, the cathode material exhibits high rate capacity, good structural stability, and low charge transfer impedance, effectively improving the battery performance of lithium batteries. The preparation method is simple, and the raw materials are inexpensive and readily available, making it suitable for large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 Schematic diagram of the equipment for the dual-heating spray dryer for the nickel-based ternary cathode material of quasi-solid-state lithium batteries of Examples 1 to 4 and Comparative Examples 2, 3, and 5 of the present application;

[0047] Among them, 1-liquid storage tank, 2-oxygen filter, 3-blower, 4-heater, 5-feed pump, 4-heating jacket, 7-spray dryer, 8-first-stage cyclone separator, 9-second-stage cyclone separator.

[0048] Figure 2 This is a flow chart for preparing nickel-based ternary positive electrode materials for quasi-solid-state lithium batteries according to Examples 1 to 4 of the present invention.

[0049] Figure 3 This is a schematic structural diagram of the nickel-based ternary positive electrode material for the quasi-solid-state lithium battery of the present invention.

[0050] Figure 4 This is a scanning electron microscope (SEM) image of the nickel-based ternary positive electrode material for a quasi-solid-state lithium battery obtained in Example 3 of the present invention.

[0051] Figure 5 This is an SEM image of the nickel-based ternary positive electrode material for a quasi-solid-state lithium battery obtained in Comparative Example 3 of the present invention.

[0052] Figure 6 This is the element distribution diagram of the nickel-based ternary positive electrode material for the quasi-solid-state lithium battery obtained in Example 3 of the present invention.

[0053] Figure 7 This is a graph showing the long cycle performance test results of the quasi-solid-state lithium battery nickel-based ternary positive electrode materials obtained in Example 3 of the present invention and Comparative Examples 1 to 4.

[0054] Figure 8 This is a graph showing the interface impedance test results of the nickel-based ternary positive electrode materials for quasi-solid-state lithium batteries obtained in Example 4 and Comparative Example 5 of the present invention.

[0055] Figure 9This is a graph showing the rate performance test results of the quasi-solid-state lithium battery nickel-based ternary positive electrode material obtained in Example 3 of the present invention and Comparative Example 1. DETAILED DESCRIPTION

[0056] The present invention will be further described below with reference to the accompanying drawings and specific examples, but the examples do not limit the present invention in any way. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0057] Unless otherwise specified, the reagents and materials used in the following examples were commercially available.

[0058] Example 1 Preparation of nickel-based ternary positive electrode materials for quasi-solid-state lithium batteries

[0059] S1. A mixed aqueous solution of nickel sulfate, cobalt sulfate, and manganese sulfate was prepared at a metal atomic molar ratio of 0.9:0.05:0.05, and ammonia was added to adjust the pH to 11. The mixture was stirred at 40°C for 12 hours, then filtered, washed, and dried to obtain powder A.

[0060] S2. First, perform ultra-high temperature spray drying and pre-sintering in a dual-heating spray dryer. The specific method is as follows:

[0061] Oxygen with a volume concentration of 99.9% is removed by an oxygen filter 2 and then heated by a blower 3 through a heater 4 before reaching the inlet of a spray dryer 7. A heating jacket 4 is used at the inlet of the spray dryer 7 to maintain the inlet temperature. Powder A is mixed evenly with magnesium ethanolate and lithium carbonate in a metal atomic molar ratio of 1:0.02:1.05 in a liquid storage tank 1, and then 40 mL of a mixture of ethanol and isopropanol in a volume ratio of 1:1 is added and mixed evenly. The mixture is then fed into the spray dryer 7 through a feed pump 5, and then pre-sintered by ultra-high temperature spray drying in an atmosphere with an oxygen volume concentration of 99.9%. The inlet temperature of the spray dryer is 500°C, the outlet temperature is 400°C, and the mixture is pre-sintered at 400°C to 500°C for 8 hours. The mixture is then separated into a solid phase and a gas phase by a first-stage cyclone separator 8, and a second solid phase and a gas phase by a second-stage cyclone separator 9. The product is collected to obtain a mixture B and the waste gas is discharged (the equipment schematic diagram of the dual heating function spray dryer is shown in FIG. 1 ). Figure 1 );

[0062] The mixture B was sintered once in a tube furnace: the temperature was raised to 750°C in a tube furnace at a heating rate of 2°C / min and sintered once for 4 hours in an atmosphere with an oxygen volume concentration of 99.9% to obtain a mixture C;

[0063] S3. LiTFSI (3 mol / L), CMC (1 wt.%), and ultrapure water were mixed to obtain a lithium salt sol. The mixture C was mixed with the lithium salt sol at a mass ratio of 1:0.1, and vacuum dried at 80°C for 4 h to obtain a quasi-solid-state lithium battery nickel-based ternary positive electrode material, whose chemical formula is Li{Ni 0.9 Co 0.05 Mn 0.05 O2}Mg 0.02 , a double-layer spherical structure (preparation flow chart as shown Figure 2 As shown, the structural diagram is as follows Figure 3 shown).

[0064] Example 2 Preparation of nickel-based ternary positive electrode materials for quasi-solid-state lithium batteries

[0065] S1. A mixed aqueous solution of nickel sulfate, cobalt sulfate, and manganese sulfate was prepared at a metal atomic molar ratio of 0.9:0.05:0.05, and ammonia was added to adjust the pH to 11. The mixture was stirred at 40°C for 12 hours, then filtered, washed, and dried to obtain powder A.

[0066] S2. First, perform ultra-high temperature spray drying and pre-sintering in a dual-heating spray dryer. The specific method is as follows:

[0067] Oxygen with a volume concentration of 99.9% is removed by an oxygen filter 2 and then heated by a blower 3 through a heater 4 before reaching the inlet of a spray dryer 7. A heating jacket 4 is used at the inlet of the spray dryer 7 to maintain the inlet temperature. Powder A is mixed evenly with zirconium ethanolate and lithium carbonate in a metal atomic molar ratio of 1:0.03:1.05 in a liquid storage tank 1, and then 40 mL of a mixture of ethanol and isopropanol in a volume ratio of 1:1 is added and mixed evenly. The mixture is then fed into the spray dryer 7 through a feed pump 5, and then pre-sintered by ultra-high temperature spray drying in an atmosphere with an oxygen volume concentration of 99.9%. The inlet temperature of the spray dryer is 500°C, the outlet temperature is 450°C, and the mixture is pre-sintered at 450°C to 500°C for 7 hours. The mixture is then separated into a solid phase and a gas phase by a first-stage cyclone separator 8, and a second solid phase and a gas phase by a second-stage cyclone separator 9. The product is collected to obtain a mixture B and the waste gas is discharged (the equipment schematic diagram of the dual heating function spray dryer is shown in FIG. 1 ). Figure 1 );

[0068] The mixture B was sintered once in a tube furnace: the mixture B was heated to 800°C at a heating rate of 2°C / min in an atmosphere with an oxygen volume concentration of 99.9% for 4 hours to obtain a mixture C;

[0069] S3. LiTFSI (2 mol / L), CMC (1 wt.%), and ultrapure water were mixed to obtain a lithium salt sol. The mixture C was mixed with the lithium salt sol at a mass ratio of 1:0.1, and vacuum dried at 80°C for 4 h to obtain a quasi-solid-state lithium battery nickel-based ternary positive electrode material, whose chemical formula is Li{Ni 0.9 Co 0.05 Mn 0.05 O2}Zr 0.03 .

[0070] Example 3 Preparation of nickel-based ternary cathode materials for quasi-solid-state lithium batteries

[0071] S1. A mixed aqueous solution of nickel sulfate, cobalt sulfate, and manganese sulfate was prepared at a metal atomic molar ratio of 0.9:0.05:0.05, and ammonia was added to adjust the pH to 11.3. The mixture was stirred at 40°C for 12 hours, then filtered, washed, and dried to obtain powder A.

[0072] S2. First, perform ultra-high temperature spray drying and pre-sintering in a dual-heating spray dryer. The specific method is as follows:

[0073] Oxygen with a volume concentration of 99.9% is removed by an oxygen filter 2 and then heated by a blower 3 through a heater 4 before reaching the inlet of a spray dryer 7. A heating jacket 4 is used at the inlet of the spray dryer 7 to maintain the inlet temperature. Powder A is mixed evenly with zirconium ethanolate, indium ethanolate, and lithium carbonate in a metal atomic molar ratio of 1:0.01:0.01:1.05 in a liquid storage tank 1, and then 40 mL of a mixture of ethanol and isopropanol in a volume ratio of 1:1 is added and mixed evenly. The mixture is then fed into the spray dryer 7 through a feed pump 5, and then pre-sintered by ultra-high temperature spray drying in an atmosphere with an oxygen volume concentration of 99.9%. The inlet temperature of the spray dryer is 550°C, the outlet temperature is 450°C, and the mixture is pre-sintered at 450°C to 550°C for 8 hours. The mixture is then separated into a solid phase and a gas phase by a first-stage cyclone separator 8, and a second solid phase and a gas phase by a second-stage cyclone separator 9. The product is collected to obtain a mixture B and the waste gas is discharged (the schematic diagram of the equipment of the dual heating function spray dryer is shown in FIG. Figure 1 shown);

[0074] The mixture B was sintered once in a tube furnace: the mixture B was heated to 800°C at a heating rate of 2°C / min in an atmosphere with an oxygen volume concentration of 99.9% for 4 hours to obtain a mixture C;

[0075] S3. LiTFSI (3 mol / L), CMC (1 wt.%), and ultrapure water were mixed to obtain a lithium salt sol. The mixture C was mixed with the lithium salt sol at a mass ratio of 1:0.1, and vacuum dried at 80°C for 4 h to obtain a quasi-solid-state lithium battery nickel-based ternary positive electrode material, whose chemical formula is Li{Ni 0.9 Co0.05 Mn 0.05 O2}Zr 0.01 In 0.01 .

[0076] Example 4 Preparation of nickel-based ternary positive electrode materials for quasi-solid-state lithium batteries

[0077] S1. A mixed aqueous solution of nickel sulfate, cobalt sulfate, and manganese sulfate was prepared at a metal atomic molar ratio of 0.9:0.05:0.05, and ammonia was added to adjust the pH to 10.4. The mixture was stirred at 40°C for 12 hours, then filtered, washed, and dried to obtain powder A.

[0078] S2. First, perform ultra-high temperature spray drying and pre-sintering in a dual-heating spray dryer. The specific method is as follows:

[0079] Oxygen with a volume concentration of 99.9% is removed by an oxygen filter 2 and then heated by a blower 3 through a heater 4 before reaching the inlet of a spray dryer 7. A heating jacket 4 is used at the inlet of the spray dryer 7 to maintain the inlet temperature. Powder A is mixed evenly with niobium ethanolate, tungsten ethanolate, and lithium carbonate in a metal atomic molar ratio of 1:0.02:0.01:1.05 in a liquid storage tank 1, and then 40 mL of a mixture of ethanol and isopropanol in a volume ratio of 1:1 is added and mixed evenly. The mixture is then fed into the spray dryer 7 through a feed pump 5, and then pre-sintered by ultra-high temperature spray drying in an atmosphere with an oxygen volume concentration of 99.9%. The inlet temperature of the spray dryer is 500°C, the outlet temperature is 400°C, and the mixture is pre-sintered at 400°C to 500°C for 7 hours. The mixture is then separated into a solid phase and a gas phase by a first-stage cyclone separator 8, and a second solid phase and a gas phase by a second-stage cyclone separator 9. The product is collected to obtain a mixture B and the waste gas is discharged (the equipment schematic diagram of the dual-heating function spray dryer is shown in FIG. 1 ). Figure 1 );

[0080] The mixture B was sintered once in a tube furnace: the temperature was raised to 750°C in a tube furnace at a heating rate of 3°C / min and sintered once for 4 hours in an atmosphere with an oxygen volume concentration of 99.9% to obtain a mixture C;

[0081] S3. LiTFSI (3 mol / L), CMC (1 wt.%), and ultrapure water were mixed to obtain a lithium salt sol. The mixture C was mixed with the lithium salt sol at a mass ratio of 1:0.1, and vacuum dried at 80°C for 4 h to obtain a quasi-solid-state lithium battery nickel-based ternary positive electrode material, whose chemical formula is Li{Ni 0.9 Co 0.05 Mn 0.05 O2}Nb 0.02 W 0.01 .

[0082] Comparative Example 1 Preparation of nickel-based ternary positive electrode materials for quasi-solid-state lithium batteries

[0083] S1. A mixed aqueous solution of nickel sulfate, cobalt sulfate, and manganese sulfate was prepared at a metal atomic molar ratio of 0.9:0.05:0.05, and ammonia was added to adjust the pH to 11.3. The mixture was stirred at 40°C for 12 hours, then filtered, washed, and dried to obtain powder A.

[0084] S2. Powder A was mixed with lithium carbonate at a metal atomic molar ratio of 1:1.05, and 40 mL of a mixture of ethanol and isopropanol at a volume ratio of 1:1 was added. The mixture was evenly dispersed in a ball mill at a speed of 250 rpm for 5 h. After blast drying, the mixture was pre-sintered at a temperature of 3°C / min to 550°C in an atmosphere of 99.9% oxygen by volume for 8 h to obtain mixture B. Mixture B was then heated to 800°C in a tube furnace at a temperature of 2°C / min and sintered once in an atmosphere of 99.9% oxygen by volume for 4 h to obtain mixture C, whose chemical formula is LiNi 0.9 Co 0.05 Mn 0.05 O2.

[0085] The difference from Example 3 is that zirconium ethoxide and indium ethoxide are not added in step S2; pre-sintering is performed in a tube furnace at 550° C.; and lithium salt sol coating in step S3 is not performed.

[0086] Comparative Example 2 Preparation of nickel-based ternary positive electrode materials for quasi-solid-state lithium batteries

[0087] S1. A mixed aqueous solution of nickel sulfate, cobalt sulfate, and manganese sulfate was prepared at a metal atomic molar ratio of 0.9:0.05:0.05, and ammonia was added to adjust the pH to 11. The mixture was stirred at 40°C for 12 hours, then filtered, washed, and dried to obtain powder A.

[0088] S2. First, perform ultra-high temperature spray drying and pre-sintering in a dual-heating spray dryer. The specific method is as follows:

[0089] Oxygen with a volume concentration of 99.9% is removed by an oxygen filter 2 and then heated by a blower 3 through a heater 4 before reaching the inlet of a spray dryer 7. A heating jacket 4 is used at the inlet of the spray dryer 7 to maintain the inlet temperature. Powder A and lithium carbonate are mixed evenly in a liquid storage tank 1 at a metal atomic molar ratio of 1:1.05, and then 40 mL of a mixture of ethanol and isopropanol with a volume ratio of 1:1 is added and mixed evenly. The mixture is then fed into the spray dryer 7 through a feed pump 5, and then pre-sintered by ultra-high temperature spray drying in an atmosphere with an oxygen volume concentration of 99.9%. The inlet temperature of the spray dryer is 500°C, the outlet temperature is 400°C, and the mixture is pre-sintered at 400°C to 500°C for 8 hours. The mixture is then separated into a solid phase and a gas phase by a first-stage cyclone separator 8, and a second solid phase and a gas phase by a second-stage cyclone separator 9. The product is collected to obtain a mixture B and the waste gas is discharged (the schematic diagram of the equipment of the dual-heating spray dryer is shown in FIG1 );

[0090] The mixture B was sintered once in a tube furnace: the mixture B was heated to 800°C at a heating rate of 2°C / min in an atmosphere with an oxygen volume concentration of 99.9% for 4 hours to obtain a mixture C;

[0091] S3. LiTFSI (3 mol / L), CMC (1 wt.%), and ultrapure water were mixed to obtain a lithium salt sol. The mixture C was mixed with the lithium salt sol at a mass ratio of 1:0.1, and vacuum dried at 80°C for 4 h to obtain a quasi-solid-state lithium battery nickel-based ternary positive electrode material, whose chemical formula is Ni 0.9 Co 0.05 Mn 0.05 O2.

[0092] The difference from Example 3 is that zirconium ethoxide and indium ethoxide are not added in step S2.

[0093] Comparative Example 3 Preparation of nickel-based ternary positive electrode materials for quasi-solid-state lithium batteries

[0094] S1. A mixed aqueous solution of nickel sulfate, cobalt sulfate, and manganese sulfate was prepared at a metal atomic molar ratio of 0.9:0.05:0.05, and ammonia was added to adjust the pH to 11.3. The mixture was stirred at 40°C for 12 hours, then filtered, washed, and dried to obtain powder A.

[0095] S2. First, perform ultra-high temperature spray drying and pre-sintering in a dual-heating spray dryer. The specific method is as follows:

[0096] Oxygen with a volume concentration of 99.9% is removed by an oxygen filter 2 and then heated by a blower 3 through a heater 4 before reaching the inlet of a spray dryer 7. A heating jacket 4 is used at the inlet of the spray dryer 7 to maintain the inlet temperature. Powder A is mixed evenly with zirconium ethanolate, indium ethanolate, and lithium carbonate in a metal atomic molar ratio of 1:0.01:0.01:1.05 in a liquid storage tank 1, and then 40 mL of a mixture of ethanol and isopropanol in a volume ratio of 1:1 is added and mixed evenly. The mixture is then fed into the spray dryer 7 through a feed pump 5, and then pre-sintered by ultra-high temperature spray drying in an atmosphere with an oxygen volume concentration of 99.9%. The inlet temperature of the spray dryer is 300°C, the outlet temperature is 250°C, and the mixture is pre-sintered at 250°C to 300°C for 8 hours. The mixture is then separated into a solid phase and a gas phase by a first-stage cyclone separator 8, and a second solid phase and a gas phase by a second-stage cyclone separator 9. The product is collected to obtain a mixture B and the waste gas is discharged (the equipment schematic diagram of the dual heating function spray dryer is shown in FIG. 1 ). Figure 1 );

[0097] The mixture B was sintered once in a tube furnace: the mixture B was heated to 800°C at a heating rate of 2°C / min in an atmosphere with an oxygen volume concentration of 99.9% for 4 hours to obtain a mixture C;

[0098] S3. LiTFSI (3 mol / L), CMC (1 wt.%), and ultrapure water were mixed to obtain a lithium salt sol. The mixture C was mixed with the lithium salt sol at a mass ratio of 1:0.1, and vacuum dried at 80°C for 4 h to obtain a quasi-solid-state lithium battery nickel-based ternary positive electrode material, whose chemical formula is Li{Ni 0.9 Co 0.05 Mn 0.05 O2}Zr 0.01 In 0.01 .

[0099] The difference from Example 3 is that in step S2, the inlet temperature of the spray drying is 300°C, the outlet temperature is 250°C, and pre-sintering is performed at 250°C to 300°C.

[0100] Comparative Example 4 Preparation of nickel-based ternary positive electrode materials for quasi-solid-state lithium batteries

[0101] S1. A mixed aqueous solution of nickel sulfate, cobalt sulfate, and manganese sulfate was prepared at a metal atomic molar ratio of 0.9:0.05:0.05, and ammonia was added to adjust the pH to 11.3. The mixture was stirred at 40°C for 12 hours, then filtered, washed, and dried to obtain powder A.

[0102] S2. Powder A was mixed with zirconium ethoxide, indium ethoxide, and lithium carbonate at a metal atomic molar ratio of 1:0.01:0.01:1.05. 40 mL of a mixture of ethanol and isopropanol in a volume ratio of 1:1 was added, and the mixture was uniformly dispersed in a ball mill at a speed of 250 rpm for 5 h. After blast drying, the mixture was pre-sintered at a heating rate of 3°C / min to 550°C in an atmosphere of 99.9% oxygen by volume for 8 h to obtain mixture B. Mixture B was then pre-sintered in a tube furnace at a heating rate of 2°C / min to 800°C in an atmosphere of 99.9% oxygen by volume for 4 h to obtain mixture C.

[0103] S3. LiTFSI (3 mol / L), CMC (1 wt.%), and ultrapure water were mixed to obtain a lithium salt sol. The mixture C was mixed with the lithium salt sol at a mass ratio of 1:0.1, and vacuum dried at 80°C for 4 h to obtain a quasi-solid-state lithium battery nickel-based ternary positive electrode material, whose chemical formula is Li{Ni 0.9 Co 0.05 Mn 0.05 O2}Zr 0.01 In 0.01 .

[0104] The difference from Example 3 is that the pre-sintering method is tube furnace sintering.

[0105] Comparative Example 5 Preparation of nickel-based ternary positive electrode materials for quasi-solid-state lithium batteries

[0106] S1. A mixed aqueous solution of nickel sulfate, cobalt sulfate, and manganese sulfate was prepared at a metal atomic molar ratio of 0.9:0.05:0.05, and ammonia was added to adjust the pH to 10.4. The mixture was stirred at 40°C for 12 hours, then filtered, washed, and dried to obtain powder A.

[0107] S2. First, perform ultra-high temperature spray drying and pre-sintering in a dual-heating spray dryer. The specific method is as follows:

[0108] After oxygen is removed from the oxygen filter 2 to reduce the volume concentration to 99.9%, it is heated by the blower 3 through the heater 4 and reaches the inlet of the spray dryer 7. The heating jacket 4 at the inlet of the spray dryer 7 maintains the inlet temperature. Powder A is mixed evenly with niobium ethanolate, tungsten ethanolate, and lithium carbonate in a metal atomic molar ratio of 1:0.02:0.01:1.05 in the liquid storage tank 1, and then 40 mL of a mixture of ethanol and isopropanol in a volume ratio of 1:1 is added and mixed evenly. The mixture is fed into the spray dryer 7 through the feed pump 5, and then pre-sintered by ultra-high temperature spray drying in an atmosphere with an oxygen volume concentration of 99.9%. The inlet temperature of the spray drying is 500°C, the outlet temperature is 400°C, and the mixture is pre-sintered at 400°C to 500°C for 7 hours. The mixture is separated into a solid phase and a gas phase by a first-stage cyclone separator 8, and a second solid phase and a gas phase by a second-stage cyclone separator 9. The product is collected to obtain a mixture B and the waste gas is discharged (the equipment schematic diagram of the dual heating function spray dryer is shown in FIG. 1). Figure 1 );

[0109] After a sintering process in a tube furnace, the mixture B was heated to 750°C at a heating rate of 3°C / min in a tube furnace and sintered for 4 hours in an atmosphere with an oxygen volume concentration of 99.9% to obtain a mixture C; the mixture C was vacuum dried at 80°C for 4 hours to obtain a quasi-solid-state lithium battery nickel-based ternary positive electrode material, whose chemical formula is Li{Ni 0.9 Co 0.05 Mn 0.05 O2}Nb 0.02 W 0.01 .

[0110] The difference from Example 4 is that the lithium salt sol coating in step S3 is not performed.

[0111] Experimental Example 1: Structural Characterization of the Nickel-Based Ternary Cathode Material for Quasi-Solid-State Lithium Batteries Prepared by the Present Invention

[0112] 1. The quasi-solid-state lithium battery nickel-based ternary cathode materials prepared in Example 3 and Comparative Example 3 were tested using SEM. The results are as follows: Figures 4 and 5 .

[0113] like Figure 4 As shown, the quasi-solid-state lithium battery nickel-based ternary positive electrode material obtained in Example 3 of the present invention has a uniform particle size distribution, regular morphology and a denser and smoother surface.

[0114] like Figure 5 As shown, the quasi-solid-state lithium battery nickel-based ternary positive electrode material obtained in Comparative Example 3 of the present invention is uniform and has a regular morphology but an uneven surface.

[0115] 2. The quasi-solid-state lithium battery nickel-based ternary cathode material prepared in Example 3 was tested using energy dispersive X-ray spectroscopy (EDS). The results are as follows: Figure 6.

[0116] like Figure 6 As shown, the Zr and In elements in the nickel-based ternary positive electrode material for the quasi-solid-state lithium battery obtained in Example 3 of the present invention are evenly distributed on the surface of the material, proving that the Zr and In elements are successfully doped.

[0117] Experimental Example 2: Performance test of nickel-based ternary cathode material for quasi-solid-state lithium battery prepared by the present invention

[0118] The nickel-based ternary cathode materials for quasi-solid-state lithium batteries obtained in Examples 3-4 and Comparative Examples 1-4 were used to form CR2032 button cells according to conventional procedures in the art. The nickel-based ternary cathode materials for quasi-solid-state lithium batteries obtained in Examples 3-4 or Comparative Examples 1-5 were uniformly mixed with a super P conductive agent and styrene-butadiene rubber (SBR) in a mass ratio of 8:1:1. N-methylpyrrolidone (NMP) was added to prepare a slurry, which was then coated on aluminum foil to form a positive electrode sheet. The sheet was vacuum-dried and cut into discs with a diameter of 13 mm.

[0119] 0.2g of tantalum-doped lithium lanthanum zirconium oxide (LLZTO) was pressed into a 14mm disc, sintered at 1100°C, polished, and magnetron sputtered with a zinc layer. Metallic lithium was melted and spread on the LLZTO to form LLZTO / Li. 3 wt.% commercial electrolyte (1.0M LiTFSI dissolved in a 1:1 volume ratio of dioxolane / ethylene glycol dimethyl ether (DOL / DME)) was added, and the pole pieces prepared above were used to form CR2032 button batteries.

[0120] The charge and discharge performance of the above-mentioned battery was tested using a Xinwei charge and discharge tester in a voltage range of 2.75 to 4.3 V. The long cycle performance test was performed on the button battery prepared from the quasi-solid-state lithium battery nickel-based ternary positive electrode material obtained in Example 3 and Comparative Examples 1 to 4 at a rate of 1C; the electrochemical impedance spectroscopy (EIS) test was performed on the button battery prepared from the quasi-solid-state lithium battery nickel-based ternary positive electrode material obtained in Example 4 and Comparative Example 5; the charge and discharge test was performed on the button battery prepared from the quasi-solid-state lithium battery nickel-based ternary positive electrode material obtained in Example 3 and Comparative Example 1 at a rate of 0.1C, 0.2C, 0.3C, 0.5C, and 1C for rate performance testing. The results are as follows: Figures 7 to 9 .

[0121] from Figure 7It can be seen that the first-cycle discharge specific capacities of the positive electrode materials prepared in Example 3 and Comparative Examples 1 to 4 at 1C are 189.7, 148.4, 141.2, 174.1 and 174.3, respectively; the discharge specific capacities after 100 cycles are 148.2, 84.8, 114.4, 129.8 and 120.3, respectively; the specific capacity attenuation rates after 100 cycles are 21.8%, 48.4%, 27.7%, 25.4% and 31.0%, respectively; this indicates that the prepared quasi-solid-state lithium battery nickel-based ternary positive electrode material Example 3 has a higher discharge specific capacity, a lower capacity attenuation rate and better long-cycle stability than the quasi-solid-state lithium battery nickel-based ternary positive electrode material prepared in Comparative Examples 1 to 4.

[0122] from Figure 8 It can be seen that the charge transfer impedance (R CT ) is 178.23Ω, and R CT =282.44Ω, indicating that the prepared quasi-solid-state lithium battery nickel-based ternary positive electrode material Example 4 has a smaller R than the quasi-solid-state lithium battery nickel-based ternary positive electrode material prepared in Comparative Example 5. CT This is attributed to the fact that the lithium salt sol improves the interfacial contact between the active components in the ternary cathode material and the solid electrolyte.

[0123] from Figure 9 It can be seen that the first cycle discharge specific capacities of Example 3 at 0.1C are 185.0, 184.3, 184.0, 184.7, and 183.5 mAh·g, respectively. -1 The discharge specific capacities at 1C are 141.4, 140.3, 139.7, 138.9, and 138.3 mAh·g, respectively. -1 The first cycle discharge specific capacities of comparative example 1 at 0.1C were 179.8, 183.2, 184.7, 182.7, and 181.7 mAh g -1 The discharge specific capacities at 1C are 122.5, 121.1, 120, 119.7, and 119.2 mAh·g, respectively. -1 It can be seen that Example 3 has better discharge specific capacity at different rates, especially exhibiting superior electrochemical performance at high rates.

[0124] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A quasi-solid-state lithium battery nickel-based ternary positive electrode material, characterized in that: The quasi-solid-state lithium battery nickel-based ternary positive electrode material consists of an inner layer and an outer layer, the inner layer is a lithium nickel cobalt manganese oxide doped with a metal element M, and the chemical formula is Li{NixCoyMn1-x-yO2}Mz; wherein 0.9≤x<1, 0≤y<0.1, x+y<1, 0.01≤z≤0.05, and M is at least one of Mg, Al, Zr, W, Y, Nb, Mo, In, and Ta; the outer layer is a lithium salt sol, and the lithium salt sol is composed of a lithium salt and a CMC hydrogel; The method for preparing the nickel-based ternary positive electrode material for a quasi-solid-state lithium battery comprises the following steps: S1: Mix and dissolve the nickel source, cobalt source, and manganese source in a solvent, adjust the pH to 10-12, filter after the reaction is complete, and post-treat the resulting solid to obtain powder A; S2: The powder A obtained in step S1 is uniformly mixed with the metal salt M and a lithium source in an organic solvent, and pre-sintered by spray drying in an oxygen atmosphere at 450-550°C for 1-10 hours to obtain a mixture B, and then sintered once in an oxygen atmosphere at 700-950°C for 5-8 hours to obtain a mixture C; S3: Mix the mixture C and the lithium salt sol evenly, and dry them to obtain a quasi-solid-state lithium battery nickel-based ternary positive electrode material.

2. The quasi-solid-state lithium battery nickel-based ternary positive electrode material according to claim 1, characterized in that: The M is one or two of Mg, Zr, In, Nb or W.

3. The quasi-solid-state lithium battery nickel-based ternary positive electrode material according to claim 2, characterized in that: The molar amount of M accounts for 1 to 5 mol% of the entire M metal element-doped lithium nickel cobalt manganese oxide.

4. The quasi-solid-state lithium battery nickel-based ternary positive electrode material according to claim 1, characterized in that: In step S1, the molar ratio of the nickel source, the cobalt source, and the manganese source is (0.9-0.95):(0.01-0.1):(0.01-0.1).

5. The quasi-solid-state lithium battery nickel-based ternary cathode material according to claim 1, characterized in that: In step S2, the molar ratio of the powder A, the metal salt M, and the lithium source is 1:(0.01-0.05):(1-1.2).

6. The quasi-solid-state lithium battery nickel-based ternary cathode material according to claim 1, characterized in that: In step S2, the M metal salt is at least one of magnesium ethoxide, aluminum ethoxide, zirconium ethoxide, tungsten ethoxide, yttrium acetate, niobium ethoxide, molybdenum ethoxide, indium ethoxide, and tantalum ethoxide.

7. The quasi-solid-state lithium battery nickel-based ternary cathode material according to claim 1, characterized in that: In step S3, the mass ratio of the mixture C to the lithium salt sol is 1:(0.05-0.2).

8. A quasi-solid-state lithium battery positive electrode sheet, characterized in that: It comprises the quasi-solid-state lithium battery nickel-based ternary positive electrode material according to any one of claims 1 to 7.

9. Use of the quasi-solid-state lithium battery nickel-based ternary cathode material according to any one of claims 1 to 7 in a lithium battery.

Images