A low-residual-alkali positive electrode material, a preparation method and application thereof

Abstract

This invention relates to a low-alkali residual cathode material, its preparation method, and its application. The method for preparing the low-alkali residual cathode material includes: S1: mechanically activating a nickel-containing precursor with a fluorine-containing activator and calcining it to obtain a first intermediate; S2: mixing the first intermediate with a lithium source and performing a segmented dry process to obtain a second intermediate; wherein the segmented dry process includes: S21, treating with a humid oxygen atmosphere at 230-270℃; S22, treating with a pulsed CO2 atmosphere at 440-520℃; S23, treating with a dry oxygen atmosphere at 550-650℃; S3: mixing the second intermediate with an ion conductor material and a dispersant, and reacting in situ to obtain a third intermediate; S4: atomically depositing a non-reactive metal oxide onto the obtained third intermediate to obtain the low-alkali residual cathode material. This invention effectively removes residual alkali and improves the performance and stability of the cathode material.

Description

Technical Field

[0001] This invention relates to the field of battery technology, specifically to a low-alkali residual cathode material, its preparation method, and its application. Background Technology

[0002] High-nickel ternary materials are widely used in the power battery field, especially in the new energy vehicle industry, due to their high energy density and low cost. Currently, problems such as gas generation and cycle degradation caused by residual alkalis (such as LiOH and Li₂CO₃) on the surface of high-nickel ternary materials are becoming increasingly prominent. The presence of residual alkalis can cause certain difficulties in the battery manufacturing process. First, residual alkalis interfere with the slurry preparation and coating process of the cathode material, resulting in poor coating uniformity, which in turn affects the overall performance of the battery. Second, the presence of residual alkalis can also hinder lithium-ion (Li₂CO₃) ion exchange. + The diffusion of alkali (Li2CO3) causes a loss of battery capacity. In addition, residual Li2CO3 on the surface can decompose at higher voltages to produce oxygen and carbon dioxide, leading to safety hazards such as battery swelling and bulging, seriously affecting the reliability and safety of the battery.

[0003] Currently, water washing is commonly used in industry to remove residual alkali from the surface. However, while water washing can effectively remove some of the residual alkali, it also leads to the loss of active lithium within the crystal lattice, damaging the surface crystal structure of the material and consequently causing a significant decrease in the material's cycle performance. Furthermore, existing calcination processes treat residual alkali with a CO2 atmosphere, but this leads to the loss of Al... 3+ The dissolution rate is >8%, and the residual alkali remains as high as 6000-8000 ppm. Industry research confirms that when the residual alkali is >5000 ppm, the battery gas production will increase exponentially. Current technical routes cannot simultaneously meet the following requirements: 1) deep removal of residual alkali (<3000 ppm); 2) maintenance of interface structure integrity; 3) low-cost industrial implementation.

[0004] Therefore, effectively reducing the surface residual alkali content of high-nickel ternary materials and optimizing their electrochemical performance while ensuring structural stability has become a pressing technical challenge. This is also an important research direction for advancing high-nickel ternary material technology. Summary of the Invention

[0005] This invention provides a low-residue cathode material and its preparation method, to solve the problem of Li-induced degradation during the removal of residual alkali from the surface of high-nickel ternary cathode materials using existing technologies. + Incomplete removal of residual alkali and Ni 2+ This exacerbates problems.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] In a first aspect, this application provides a method for preparing a low-residue cathode material, comprising the following steps: S1: Mechanically activate the nickel-containing precursor with a fluorine-containing activator, then calcine to obtain the first intermediate; S2: The first intermediate is mixed with a lithium source and subjected to segmented dry processing to obtain the second intermediate; The segmented dry processing includes: S21, treated with a humid oxygen atmosphere at 230-270℃; S22, treated with a pulsed CO2 atmosphere at 440-520℃; S23 is treated with a dry oxygen atmosphere at 550-650℃. S3: The second intermediate is mixed with an ionic conductor material and a dispersant, and reacted in situ to obtain the third intermediate; S4: Perform atomic deposition of inactive metal oxides on the obtained third intermediate to obtain the low residual alkali cathode material.

[0008] The segmented dry treatment is relative to the wet washing method. The water vapor content in the humid oxygen atmosphere is controlled at 5-15 vol%, which is insufficient to form liquid water cleaning material. Therefore, the overall treatment method is still a dry treatment.

[0009] In one optional embodiment, the water vapor content in the humid oxygen atmosphere in S21 is 5-15 vol%, and the treatment time is 1-3 hours. In S22, the CO2 concentration is 50-100 vol%, the pulse period is 30-60 seconds, and the treatment time is 2-4 hours. In S23, the oxygen concentration is >99.5%, and the treatment time is 2-5 hours.

[0010] In an optional embodiment, the fluorinated activator in S1 comprises a fluorinated compound and a metal oxide; the fluorinated compound comprises at least one of lithium fluoride, magnesium fluoride, aluminum fluoride, calcium fluoride, titanium fluoride, and zirconium fluoride; optionally, the fluorinated compound is aluminum fluoride; the metal oxide comprises at least one of titanium oxide, zirconium oxide, aluminum oxide, calcium oxide, manganese oxide, magnesium oxide, and vanadium oxide; optionally, the metal oxide is titanium oxide; optionally, the mass ratio of the fluorinated compound to the metal oxide is 1:(0.5-1); optionally, the particle size of the fluorinated activator is 180-220 nm.

[0011] As an example, the particle size of the fluorinated activator may be 180 nm, 190 nm, 200 nm, 210 nm, 220 nm, or within any of the above values.

[0012] In one optional embodiment, the nickel-containing precursor in S1 is Ni. x Coy (OH)₂, where x ranges from 0.8 to 0.95, y ranges from 0.05 to 0.2, and x + y = 1; the mass ratio of the nickel-containing precursor to the fluorine-containing activator is (40-70):1. The molar ratio of lithium element in the lithium source to the total amount of transition metals in the first intermediate is (1.025-1.05):1.

[0013] In an optional embodiment, in step S1, the mechanical activation is performed using mechanical ball milling for 20-60 minutes at a speed of 300-600 rpm. This mechanochemical activation technique treats the nickel-containing precursor and activator, enhancing the precursor's reactivity and promoting the formation of an fluorine passivation layer. The passivation layer effectively improves the material's stability and reduces chemical reactivity during subsequent calcination and use, thereby optimizing the cathode material's performance. By controlling the addition of the activator and the ball milling conditions, a uniform distribution of fluorine can be achieved, ensuring the effective formation of the passivation layer on the material surface. Furthermore, the calcination is divided into two stages, both in a pure oxygen atmosphere: the first stage is calcination at 350-500℃ for 4-6 hours, and the second stage is calcination at 750-850℃ for 11-14 hours.

[0014] In an optional embodiment, the ion conductor material in S3 includes at least one of zirconium phosphate nanoparticles, lithium zirconium phosphate nanoparticles, aluminum phosphate nanoparticles, lithium iron phosphate nanoparticles, lithium titanium phosphate nanoparticles, lithium titanium aluminum phosphate nanoparticles, and lithium vanadium phosphate nanoparticles; optionally, the ion conductor material is zirconium phosphate nanoparticles; optionally, the ion conductor material may also use at least one of lithium zirconium phosphate nanoparticles, aluminum phosphate nanoparticles, lithium iron phosphate nanoparticles, lithium titanium phosphate nanoparticles, lithium titanium aluminum phosphate nanoparticles, and lithium vanadium phosphate nanoparticles; the dispersant includes at least one of ammonium polyacrylate, polyvinyl alcohol, sodium polyacrylate, polyethyleneimine, sodium polystyrene sulfonate, and polyvinylpyrrolidone; optionally, the dispersant is ammonium polyacrylate; the mass ratio of the ion conductor material to the second intermediate is 0.0015-0.0025:1; the particle size D of the ion conductor material... v 50 is 80-100 nm; the mass ratio of the dispersant to the second intermediate is 0.001-0.004:1.

[0015] The selected ion conductor material exhibits excellent ion conductivity, and its nanoscale size effectively promotes rapid ion transport within the cathode material. Through in-situ reaction at an appropriate temperature, nanoparticles are uniformly distributed on the material surface, forming a highly efficient fast ion conductor layer, which significantly improves the battery's charge-discharge performance and cycle stability.

[0016] In one optional embodiment, in step S3, the in-situ reaction temperature is 60-90°C and the time is 2-4 hours. In step S4, the atomic deposition time is 20-60 minutes and the temperature is 250-400°C. By controlling the temperature and time of the atomic deposition process, a thin film can be uniformly deposited on the material surface, reducing interfacial stress, preventing crack propagation, and thus improving the structural stability and cycle life of the material.

[0017] In an optional embodiment, in step S4, the inactive metal oxide includes at least one of α-alumina, β-alumina, and titanium oxide.

[0018] Secondly, the present invention also provides a low residual alkali cathode material, which is prepared by the above-described preparation method.

[0019] Thirdly, the present invention also provides a lithium-ion battery comprising the aforementioned low-alkali cathode material.

[0020] Fourthly, the present invention also provides an electrical device including the aforementioned lithium-ion battery.

[0021] The technical solution of this application has the following advantages: (1) This invention utilizes a mechanochemical activation process, employing a fluorine-containing activator to pre-activate the nickel-containing ternary cathode material. This not only removes residual alkali (Li₂CO₃ and LiOH) from the material surface but also avoids the problems associated with traditional water washing methods. + This minimizes dissolution loss and ensures lithium-ion retention in the material. Furthermore, the formed F passivation layer effectively protects the material surface, reducing adverse reactions in subsequent processing and improving the structural stability of the cathode material. This invention utilizes a three-stage gradient atmosphere treatment (wet oxygen atmosphere, pulsed CO2 atmosphere, and dry oxygen atmosphere) to make residual alkali removal more efficient and controllable. The atmosphere gradient technology can precisely target and remove Li2CO3 and LiOH without affecting the crystal structure of the cathode material. Compared to traditional processes, this improves the electrochemical performance of the material and avoids problems such as gas generation. A fast ion conductor layer is generated, enhancing the ionic conductivity of the material. The fast ion conductor layer generated on the material surface through in-situ reaction significantly improves the ionic conductivity of the cathode material. The introduction of the ion conductor material not only improves the material's conductivity but also enhances the battery's charge-discharge efficiency and cycle stability, reducing performance degradation after prolonged use.

[0022] (2) This invention forms an interface protective film through low-temperature atomic deposition, avoiding the accumulation of thermal stress that may occur during high-temperature deposition and significantly reducing the generation of interface cracks. During battery use, the reduction of interface cracks greatly improves the cycle life and stability of the cathode material, enabling the battery to maintain good performance during high-rate charge and discharge. Detailed Implementation

[0023] The following embodiments are provided to better understand the present invention, but the following embodiments do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the scope of protection of the present invention.

[0024] Unless otherwise specified, all experimental steps or conditions in the examples were performed according to conventional experimental procedures and conditions in the art. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0025] The nickel-cobalt precursor used in this invention is nickel-cobalt hydroxide, which was purchased from Jingmen GEM Co., Ltd.

[0026] The fluorine-containing activator, lithium salt, zirconium phosphate nanoparticles, ammonium polyacrylate, and alumina used in this invention were all purchased from Aladdin.

[0027] Example 1 This embodiment provides a method for preparing a low-residue cathode material. The specific preparation method and operating parameters are as follows: S1: Ni, the nickel-cobalt precursor 0.9 Co 0.1 (OH)2 and a fluorine-containing composite activator (AlF3 / TiO2, mass ratio 1:1, particle size D) v The mixture (50 for 200 nm) was mechanically ball-milled at a mass ratio of 50:1 at a speed of 400 rpm under nitrogen protection for 40 minutes. Subsequently, the mixture was calcined at 400°C in a pure oxygen atmosphere for 5 hours, and then calcined at 800°C for 12 hours.

[0028] S2: The obtained nickel-cobalt material and lithium salt LiOH were subjected to staged treatment in a gradient atmosphere system, with a molar ratio of nickel-cobalt material to lithium element in the lithium salt of 1:1.03. First, the material was treated with a wet oxygen atmosphere at 250°C, followed by a pulsed CO2 atmosphere treatment at 480°C (pulse frequency of 1Hz, duty cycle of 40%), and finally a dry oxygen atmosphere treatment at 600°C to remove residual alkali from the material.

[0029] The treatment process included a humid oxygen atmosphere with a water vapor content of 10 vol% and a treatment time of 2 hours. The pulsed CO2 atmosphere treatment involved a CO2 concentration of 80 vol%, a pulse period of 45 seconds, and a treatment time of 3 hours. Finally, the dry oxygen atmosphere treatment had an oxygen concentration of 99.5% and a treatment time of 3.5 hours.

[0030] S3: Add particle size D to the treated material vZirconium phosphate nanoparticles (90 nm in diameter) and ammonium polyacrylate dispersant were reacted in situ at 85 °C for 3 h to form an ion-conducting layer. The mass of the zirconium phosphate nanoparticles and the mass of the ammonium polyacrylate dispersant were 0.2% of the second intermediate.

[0031] S4: Perform atomic deposition on the material using α-alumina to deposit an Al2O3 film at 300°C for 20 minutes to form a protective interface film.

[0032] Thus, the low residual alkali cathode material described in this invention is obtained.

[0033] Example 2 This embodiment provides a method for preparing a low-residue cathode material. The specific preparation method and operating parameters are as follows: S1: Ni, the nickel-cobalt precursor 0.8 Co 0.2 (OH)2 and fluorine-containing composite activator (AlF3 / TiO2, mass ratio 1:0.7, particle size D) v The mixture (50 for 220 nm) was mechanically ball-milled at a mass ratio of 40:1 at a speed of 600 rpm under nitrogen protection for 60 minutes. Subsequently, the mixture was calcined at 500°C in a pure oxygen atmosphere for 6 hours, and then calcined at 850°C for 14 hours.

[0034] S2: The obtained nickel-cobalt material and lithium salt LiOH were subjected to staged treatment in a gradient atmosphere system, with a molar ratio of nickel-cobalt material to lithium salt of 1:1.025. First, the material was treated with a humid oxygen atmosphere at 270°C, followed by a pulsed CO2 atmosphere treatment at 520°C (pulse frequency of 1Hz, duty cycle of 40%), and finally a dry oxygen atmosphere treatment at 650°C to remove residual alkali from the material.

[0035] The treatment consisted of three phases: a humid oxygen atmosphere with a water vapor content of 5 vol% and a treatment time of 2 hours; a pulsed CO2 atmosphere with a CO2 concentration of 50 vol% and a pulse period of 30 seconds and a treatment time of 2 hours; and a final dry oxygen atmosphere treatment with an oxygen concentration of 99.5% and a treatment time of 2 hours.

[0036] S3: Add particle size D to the treated material v Zirconium phosphate nanoparticles (100 nm in diameter) and a dispersant were reacted in situ at 60 °C for 2 h to form an ion-conducting layer. The mass of the zirconium phosphate nanoparticles was 0.25% of the second intermediate, and the dispersant was ammonium polyacrylate, which accounted for 0.4% of the mass of the second intermediate.

[0037] S4: Perform atomic deposition on the material using β-alumina to deposit an Al2O3 film at 400°C for 60 minutes to form a protective interface film.

[0038] Thus, the low residual alkali cathode material described in this invention is obtained.

[0039] Example 3 This embodiment provides a method for preparing a low-residue cathode material. The specific preparation method and operating parameters are as follows: S1: Ni, the nickel-cobalt precursor 0.95 Co 0.05 (OH)2 and fluorine-containing composite activator (AlF3 / TiO2, mass ratio 1:0.5, particle size D) v The mixture (50 for 180 nm) was mechanically ball-milled at a mass ratio of 70:1 at 300 rpm for 20 minutes under nitrogen protection. Subsequently, the mixture was calcined at 350°C in a pure oxygen atmosphere for 4 hours, and then calcined at 750°C for 11 hours.

[0040] S2: The obtained nickel-cobalt material was subjected to staged treatment in a gradient atmosphere system, with a molar ratio of nickel-cobalt material to lithium salt of 1:1.05. First, it was treated with a wet oxygen atmosphere at 230°C, then with a pulsed CO2 atmosphere at 440°C (pulse frequency of 1Hz, duty cycle of 40%), and finally with a dry oxygen atmosphere at 650°C to remove residual alkali from the material.

[0041] The treatment process involved a humid oxygen atmosphere with a water vapor content of 15 vol% and a treatment time of 3 hours. The pulsed CO2 atmosphere treatment involved a CO2 concentration of 100 vol%, a pulse period of 60 seconds, and a treatment time of 4 hours. Finally, the dry oxygen atmosphere treatment involved an oxygen concentration of 99.5% and a treatment time of 5 hours.

[0042] S3: Add particle size D to the treated material v Zirconium phosphate nanoparticles (80 nm in diameter) and a dispersant were reacted in situ at 90 °C for 4 h to form an ion-conducting layer. The mass of the zirconium phosphate nanoparticles was 0.15% of the second intermediate, and the dispersant was ammonium polyacrylate, which accounted for 0.1% of the mass of the second intermediate.

[0043] S4: Perform atomic deposition on the material using β-alumina to deposit an Al2O3 film at 250°C for 20 minutes to form a protective interface film.

[0044] Thus, the low residual alkali cathode material described in this invention is obtained.

[0045] Example 4 The difference between this embodiment and Embodiment 1 is that the ionic conductor material in S3 is lithium aluminum titanium phosphate nanoparticles, and the dispersant is polyvinylpyrrolidone. The addition ratio and reaction conditions are the same as in Embodiment 1.

[0046] Comparative Example 1 This comparative example provides a method for preparing a low-residue cathode material. The method is a traditional water washing method, and the steps include: introducing the sample obtained in S2 and deionized water into a beaker at a mass ratio of 1:0.8, stirring for 5 minutes, then pouring it into a conical funnel for filtration and drying in a vacuum drying oven. The other steps are the same as in Example 1.

[0047] Comparative Example 2 This comparative example provides a method for preparing a low residual alkali cathode material, which differs from Example 1 in that it does not use a coating material, i.e., it does not use S3 and S4.

[0048] Comparative Example 3 This comparative example provides a method for preparing a low residual alkali cathode material. The difference between this method and Example 1 is that S2 uses a single-stage treatment, in which the obtained nickel-cobalt material is directly treated at 650°C in a dry oxygen atmosphere for 3 hours to remove residual alkali from the material.

[0049] Comparative Example 4 The difference between this comparative example and Example 1 is that mechanical activation treatment is not used.

[0050] The detection methods and standards for test data in this invention are as follows.

[0051] The low-alkali residual cathode materials provided in Examples 1-4 and Comparative Examples 1-4 were used as cathode materials for lithium-ion batteries to prepare coin cells. The preparation method is as follows: The cathode material (the low-alkali residual cathode material prepared in Examples 1-4 or Comparative Examples 1-4), the binder is polyvinylidene fluoride (PVDF), the conductive agent is conductive carbon black (SP), and the solvent is N-methylpyrrolidone (NMP) in a ratio of 95g:1g:4g:220mL. The mixture was stirred to form a slurry, coated on copper foil, and dried and rolled to obtain a cathode sheet. Lithium hexafluorophosphate (LiPF6) was used as the electrolyte, and a mixture of ethylene carbonate (EC) and diethyl carbonate (DEC) in a volume ratio of 1:1 was used as the solvent to prepare an electrolyte solution with a concentration of 1mol / L. A lithium metal sheet was used as the counter electrode, and a polypropylene (PP) membrane was used as the separator. The CR2032 coin cell was assembled in an argon-filled glove box.

[0052] Electrochemical performance tests were conducted on coin cells containing the low-alkali residual cathode materials of Examples 1-4 and Comparative Examples 1-4. The tests were performed using a Wuhan Landian CT2001A battery tester. The charge / discharge voltage range was 2.5-4.25V. The capacity retention after 50 cycles at a charge / discharge rate of 0.2C and the first charge / discharge capacity at 3C were tested, with the charge / discharge voltage range consistent with that at 0.2C. The EIS was measured on an electrochemical workstation, and the results are shown in Table 1.

[0053] Residual alkali test method: 1. Preparation of standard solution: Use hydrochloric acid (HCl) as the standard titrant and dilute to the required concentration. Ensure that deionized water is boiled before testing to remove carbon dioxide and avoid interference with the measurement results.

[0054] 2. Sample preparation: Weigh 30 grams of the positive electrode material sample to be tested, add an appropriate amount of deionized water, and stir thoroughly to ensure that the sample is evenly dispersed.

[0055] 3. Potentiometric titration: Titration is performed using a potentiometric titrator, and the change in electrode potential is monitored to determine the titration endpoint. During the titration, hydrochloric acid reacts with LiOH and Li2CO3 in the sample, and the amount of hydrochloric acid consumed can be used to calculate the residual alkali content.

[0056] 4. Data processing: Based on the volume and concentration of the standard solution consumed in the titration, and combined with the stoichiometric relationship of the chemical reaction, the residual alkali content in the sample is calculated.

[0057] Table 1 shows the performance test data of the ternary cathode materials obtained in Examples 1-4 and Comparative Examples 1-4 of the present invention, including cycle performance, rate performance, total residual alkali and electrochemical impedance spectroscopy (EIS).

[0058] Table 1 Performance test data of the cathode materials obtained in Examples 1-4 and Comparative Examples 1-4

[0059] In summary, the test data in Table 1 show that the embodiments of this application achieve an optimal balance between residual alkali control and electrochemical performance through the synergistic combination of mechanical activation (S1), segmented atmosphere treatment (S2), in-situ coating (S3), and atomic layer deposition (S4), which is significantly better than the comparative examples.

[0060] Specifically, Comparative Example 1 used a traditional water washing method, which, due to lattice lithium loss and surface structure damage, could not simultaneously achieve low residual alkali and high structural stability. Comparative Example 3 omitted the segmented atmosphere treatment and used a single-stage high-temperature treatment, resulting in incomplete removal of residual alkali and thermal damage to the material surface. Its cycle retention rate and rate performance were significantly inferior to the examples, indicating that the gradient alkali removal and structural repair mechanism of segmented atmosphere treatment is irreplaceable. Comparative Example 4 omitted the S1 mechanical activation step. Due to the lack of a fluoride passivation layer, the material's surface activity was too high during subsequent treatments, leading to a significantly higher residual alkali content than the examples and a reduced cycle retention rate, demonstrating the crucial role of mechanical activation in the pre-stabilization of the material surface.

[0061] It is worth noting that Comparative Example 2, by retaining S1 and S2 but omitting S3 and S4, had a residual alkali content close to that of the Example. However, due to the lack of protection from the ion conductor layer and oxide protective film, its cycle retention rate dropped sharply, and its EIS impedance was high, making it the worst among all test groups. This demonstrates that steps S3 and S4 constructed a stable interface protective layer.

[0062] Therefore, the technical solution of this application achieves both deep removal of residual alkali and long-term cycle stability through the organic coupling of S1 (surface pre-activation), S2 (segmented atmosphere deep alkali removal), S3 (fast ion conductor layer construction), and S4 (interface passivation), overcoming long-standing technical biases in the field and achieving significant technical progress. The omission or substitution of any single process (as shown in Comparative Examples 1-4) leads to significant degradation of material performance, proving that the four-step synergistic process of this application has unpredictable technical effects. Therefore, the technical solution of this invention effectively improves the overall performance of the cathode material and has good application prospects.

[0063] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing a low-residue cathode material, characterized in that, Includes the following steps: S1: Mechanically activate the nickel-containing precursor with a fluorine-containing activator, then calcine to obtain the first intermediate; S2: The first intermediate is mixed with a lithium source and subjected to segmented dry processing to obtain the second intermediate; The segmented dry processing includes: S21, treated with a humid oxygen atmosphere at 230-270℃; S22, treated with a pulsed CO2 atmosphere at 440-520℃; S23 is treated with a dry oxygen atmosphere at 550-650℃. S3: The second intermediate is mixed with an ionic conductor material and a dispersant, and reacted in situ to obtain the third intermediate; S4: Perform atomic deposition of inactive metal oxides on the obtained third intermediate to obtain the low residual alkali cathode material.

2. The method for preparing the low-residue cathode material according to claim 1, characterized in that, The humid oxygen atmosphere described in S21 contains 5-15 vol% water vapor, and the treatment time is 1-3 hours; And / or, the CO2 concentration in S22 is 50-100 vol%, the pulse period is 30-60 s, and the treatment time is 2-4 hours; And / or, the oxygen concentration in S23 is not less than 99.5%, and the treatment time is 2-5 hours.

3. The method for preparing the low residual alkali cathode material according to claim 1, characterized in that, The fluorine-containing activator mentioned in S1 includes fluorine-containing compounds and metal oxides; Optionally, the fluorinated compound includes at least one of lithium fluoride, magnesium fluoride, aluminum fluoride, calcium fluoride, titanium fluoride, and zirconium fluoride; more preferably, the fluorinated compound is aluminum fluoride. Optionally, the metal oxide includes at least one of titanium oxide, zirconium oxide, aluminum oxide, calcium oxide, manganese oxide, magnesium oxide, and vanadium oxide; more preferably, the metal oxide is titanium oxide. Optionally, the mass ratio of the fluorine-containing compound to the metal oxide is 1:(0.5-1). Optionally, the particle size of the fluorinated activator is 180-220 nm.

4. The method for preparing the low-residue cathode material according to claim 1, characterized in that, The nickel-containing precursor mentioned in S1 is Ni x Co y (OH)2, where x ranges from 0.8 to 0.95, y ranges from 0.05 to 0.2, and x + y = 1; And / or, the mass ratio of the nickel-containing precursor to the fluorine-containing activator is (40-70):1; And / or, the molar ratio of lithium element in the lithium source to the total amount of transition metal in the first intermediate is (1.025-1.05):

1.

5. The method for preparing the low-residue cathode material according to claim 1, characterized in that, The mechanical activation described in S1 includes: ball milling under a protective atmosphere; optionally, the ball milling time is 20-60 min and the ball milling speed is 300-600 rpm; And / or, the calcination includes: calcining at 350-500℃ for 4-6 hours in a pure oxygen atmosphere, followed by calcination at 750-850℃ for 11-14 hours.

6. The method for preparing the low-residue cathode material according to claim 1, characterized in that, The ion conductor material described in S3 includes at least one of zirconium phosphate nanoparticles, lithium zirconium phosphate nanoparticles, aluminum phosphate nanoparticles, lithium iron phosphate nanoparticles, lithium titanium phosphate nanoparticles, lithium titanium aluminum phosphate nanoparticles, and lithium vanadium phosphate nanoparticles; optionally, the ion conductor material is zirconium phosphate nanoparticles. And / or, the dispersant comprises at least one of ammonium polyacrylate, polyvinyl alcohol, sodium polyacrylate, polyethyleneimine, sodium polystyrene sulfonate, and polyvinylpyrrolidone; optionally, the dispersant is ammonium polyacrylate; And / or, the mass ratio of the ionic conductor material to the second intermediate is 0.0015-0.0025:1; And / or, the particle size D of the ion conductor material v 50 is 80-100nm; And / or, the mass ratio of the dispersant to the second intermediate is 0.001-0.004:

1.

7. The method for preparing the low-residue cathode material according to any one of claims 1-6, characterized in that, The in-situ reaction described in S3 is carried out at a temperature of 60-90℃ for 2-4 hours. And / or, the atomic deposition described in S4 has a deposition time of 20-60 min and a temperature of 250-400 °C; And / or, the inactive metal oxides described in S4 include at least one of α-alumina, β-alumina, and titanium oxide.

8. A low-residual-alkali cathode material, characterized in that, It is prepared by the preparation method according to any one of claims 1-7.

9. A lithium-ion battery, characterized in that, Including the low residual alkali cathode material as described in claim 8.

10. An electrical appliance, characterized in that, Including the lithium-ion battery as described in claim 9.

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