A lithium ion battery cathode material with high interfacial conductance and a preparation method thereof

Abstract

The application provides a lithium ion battery positive electrode material with high interfacial conductance and a preparation method thereof, and belongs to the technical field of new energy battery electrode materials. The preparation method of the lithium ion battery positive electrode material comprises the following steps: under the protection of nitrogen, a metal salt solution containing nickel, cobalt and manganese is reacted with a precipitant and a complexing agent to synthesize a dense spherical NCM precursor; the NCM, LiOH.H2O, LiF and anhydrous ethanol are uniformly ball milled, and dense sintering is performed to obtain fluorine-doped NCM powder; LiNO3, NH4H2PO4, urea and deionized water are mixed to prepare a precursor solution, the precursor solution is uniformly loaded on the fluorine-doped NCM powder by using a rotary evaporation method, and heat treatment is performed to obtain a lithium-phosphorus-oxygen-nitrogen glass phase coated fluorine-doped NCM composite material; carboxylated multi-walled carbon nanotubes are dispersed in anhydrous ethanol, the LiPON coated fluorine-doped NCM composite material and phenolic resin are added, and carbonization is performed to obtain the positive electrode material. The lithium ion battery positive electrode material obtained by the above method has high interfacial conductance and significantly improved long cycle life.

Description

Technical Field

[0001] This invention relates to the field of new energy battery electrode materials technology, and in particular to a lithium-ion battery cathode material with high interfacial conductivity and its preparation method. Background Technology

[0002] With the ever-increasing energy density demands of electric vehicles and large-scale energy storage systems, the development of cathode materials for lithium-ion batteries is crucial. High-nickel layered oxides, such as LiNi, are a key example. 0.8 Co 0.1 Mn 0.1 O2 (NCM811) has become a key cathode material due to its high reversible capacity (≈200mAh / g) and cost advantage. However, its insufficient bulk electronic conductivity and slow interfacial charge transfer kinetics lead to increased polarization and capacity decay at high rates and low temperatures.

[0003] The bottleneck of existing modification strategies lies in scale mismatch: although single-phase doping can stabilize lattice oxygen, it is difficult to suppress surface parasitic reactions; although traditional surface coating can isolate electrolytes, the geometric inhomogeneity of non-functional coating layers (such as inert oxides) will introduce additional ion transport barriers. This "functional separation" design fails to achieve synergistic optimization of bulk phase and interface, resulting in mutual constraints on modification effects.

[0004] Therefore, addressing the issue of poor performance of NCM811 in cathode materials at high rates and low temperatures is crucial to overcoming the bottleneck of NCM811's kinetic performance. Summary of the Invention

[0005] To address the problems mentioned in the background art, this invention provides a method for preparing a lithium-ion battery cathode material with high interfacial conductivity, using a layered high-nickel ternary material (NCM811) as the core, and modifying it with fluorine doping, interfacial fast ion conductor coating, and surface conductive composite layer.

[0006] Specifically:

[0007] This invention provides a method for preparing a lithium-ion battery cathode material with high interfacial conductivity, the steps of which include:

[0008] Step 1: Under nitrogen protection, a metal salt solution containing nickel, cobalt, and manganese is placed in a batch reactor along with a precipitant and a complexing agent. After aging, washing, and drying, spherical NCM is obtained.

[0009] Step 2: The NCM, LiOH·H2O, and LiF obtained in Step 1 are ball-milled with anhydrous ethanol until homogeneous. After drying, they are sintered in an oxygen atmosphere and cooled in the furnace to obtain fluorine-doped NCM powder. The mass ratio of NCM, LiOH·H2O, and LiF is (9-10):(4.5-5):(0.08-0.09).

[0010] Step 3: Prepare a precursor solution by mixing LiNO3, NH4H2PO4, urea, and deionized water. Use a rotary evaporation method to uniformly load the precursor solution onto the fluorine-doped NCM powder obtained in Step 2. After drying, heat treat in an argon atmosphere and cool to obtain LiPON-coated fluorine-doped NCM composite material. The mass ratio of the precursor solution to the fluorine-doped NCM powder is (0.1-0.2):10.

[0011] Step 4: Disperse carboxylated multi-walled carbon nanotubes in anhydrous ethanol, add the LiPON-coated fluorine-doped NCM composite material obtained in Step 3, and phenolic resin, evaporate and dry, carbonize in an argon atmosphere, cool, grind and sieve to obtain the cathode material.

[0012] Furthermore, the preparation steps of the metal salt solution containing nickel, cobalt, and manganese in step one include: placing 22.5–25 parts by mass of NiSO4·6H2O, 3–4 parts by mass of CoSO4·7H2O, and 1.7–1.8 parts by mass of MnSO4·H2O into 50–55 parts by mass of deionized water and dissolving them evenly.

[0013] The precipitant is a 2.0-2.2 mol / L NaOH solution; the complexing agent is a 0.5-0.6 mol / L NH3·H2O solution; the mass ratio of the metal salt solution containing nickel, cobalt, and manganese to the precipitant and complexing agent is (5-6):(10-11):(5-6).

[0014] Furthermore, in step one, the operating temperature is 55–60°C, and the pH is controlled at 11.4–11.6.

[0015] Furthermore, the sintering in the oxygen atmosphere in step two includes first treating at 500-520℃ for 5-6 hours, then raising the temperature to 750-770℃ for 10-11 hours, and then raising the temperature to 880-890℃ for 10-11 hours.

[0016] Furthermore, the preparation steps of the precursor solution in step three include: placing 0.2–0.22 parts by mass of LiNO3, 0.13–0.15 parts by mass of NH4H2PO4, and 0.03–0.05 parts by mass of urea into 20–22 parts by mass of deionized water, and mixing thoroughly.

[0017] Furthermore, the heat treatment in the argon atmosphere in step three includes first holding at 350–370°C for 2–3 hours, and then raising the temperature to 600–620°C for 5–6 hours.

[0018] Further, in step four, 0.15–0.17 parts by mass of carboxylated multi-walled carbon nanotubes, 9–10 parts by mass of LiPON-coated fluorine-doped NCM composite material, and 0.3–0.5 parts by mass of phenolic resin are dispersed in 100–105 parts of anhydrous ethanol.

[0019] Furthermore, the carbonization in the argon atmosphere in step four includes pre-curing at 350–370°C for 1–1.5 h, followed by carbonization at 650–670°C for 2–2.5 h.

[0020] In addition, the present invention also provides a lithium-ion battery cathode material with high interfacial conductivity, which is prepared by the above-mentioned lithium-ion battery cathode material preparation method.

[0021] Compared with the prior art, the beneficial features of the present invention are as follows:

[0022] 1. The method for preparing the lithium-ion battery cathode material of the present invention firstly involves fluorine doping optimizing the bulk phase lattice structure, slightly increasing the lithium interlayer spacing, and suppressing cation mixing, thus removing intrinsic obstacles to the rapid insertion and extraction of lithium ions. Based on this, the lithium phosphorus oxynitride (LiPON) glass phase coated on the particle surface plays a crucial role. As an ultrathin, highly ionicly conductive interface layer, it significantly reduces the energy barrier for lithium ions to cross the solid-liquid interface, providing a "highway" for ion transport. Simultaneously, the outermost carbon nanotube and amorphous carbon composite network acts like a conductive mesh covering and connecting the particles, ensuring that electrons can be instantly and efficiently transported to each active reaction site under high current demands. The synergistic effect of these three elements is that a stable bulk phase provides the foundation for fast charging and discharging, the fast ion conductor coating layer solves the interface ion transport bottleneck, and the three-dimensional electron network eliminates external current collection resistance. The synergistic effect of these three elements maximizes the transport efficiency of both ions and electrons, enabling the material to maintain a high capacity output even at high rates of 5C or low temperatures of -20°C.

[0023] 2. The lithium-ion battery cathode material preparation method of this invention constructs multiple protection mechanisms at different scales to synergistically stabilize the structural integrity of the cathode material during long-term cycling. Fluorine doping, through the formation of strong metal-fluorine bonds, firmly "anchors" transition metal ions and stabilizes lattice oxygen at the atomic level. This is fundamental to suppressing the transformation of the bulk structure from layered to rock salt phase and mitigating reversible lithium loss and voltage decay. However, bulk stabilization alone is insufficient to cope with the erosion from the electrolyte. At this point, the uniform and dense lithium-phosphorus-oxygen-nitrogen glassy phase coating layer plays the role of a "chemical barrier." It physically isolates the active material from direct contact with the electrolyte, almost completely blocking the dissolution of transition metals, surface residual lithium side reactions, and the generation of electrolyte decomposition products. The synergistic effect of these three elements is as follows: fluorine doping strengthens the material's internal structure, making it less susceptible to fatigue damage from repeated lithium-ion insertion and extraction; the lithium-phosphorus-oxygen-nitrogen coating acts like a protective suit, resisting the corrosive effects of the external chemical environment; and the outer carbon composite layer further acts as a buffer layer and a fixing network, absorbing the micro-stress generated during cycling and preventing the coating and the particles themselves from cracking and failing due to volume changes. This synergistic protection from the inside out greatly extends the battery's cycle life.

[0024] 3. The lithium-ion battery cathode material preparation method of the present invention constructs a three-level synergistic structure of "bulk phase-interface-surface phase". The first level involves strengthening the bulk lattice through high-temperature solid-phase fluorine doping. During high-temperature sintering, fluorine is introduced... - Partially replaces O 2- The first stage involves the formation of highly energetic MF bonds through lattice points, which act as "anchors" to lock in the transition metal, effectively inhibiting its migration and oxygen loss during cycling, and significantly mitigating phase transitions and voltage decay. The second stage involves the construction of interfacial ion channels through the coating of a lithium phosphorus oxynitride (LiPON) glass phase. The dense LiPON layer physically isolates the highly active core from the electrolyte, completely blocking HF corrosion and side reactions, and stabilizing the CEI. The third stage involves the formation of an outer three-dimensional electronic network through the composite coating of carbon nanotubes and amorphous carbon (CNT-C). The amorphous carbon formed after the carbonization of phenolic resin achieves continuous and uniform coating on the particle surface ("surface"), while the CNTs interspersed within it act as bridges and conductive "wires" between particles ("lines"). Together, they construct a three-dimensional conductive network that runs through the electrode. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] To facilitate implementation of this invention by those skilled in the art, some of the reagents used in the embodiments and comparative examples are now described:

[0027] NiSO4·6H2O: Shandong Haoshun Chemical Co., Ltd., 99% analytical grade;

[0028] CoSO4·7H2O: Shandong Haoshun Chemical Co., Ltd., 99% analytical grade;

[0029] MnSO4·H2O: Shandong Haoshun Chemical Co., Ltd., 99% analytical grade;

[0030] NH3·H2O: Shandong Haoshun Chemical Co., Ltd., 99% analytical grade;

[0031] LiOH·H2O: Shandong Haoshun Chemical Co., Ltd., 99% analytical grade;

[0032] LiF: Wuhan Chujiang Haoyu Chemical Technology, 99%;

[0033] LiNO3: Wuhan Chujiang Haoyu Chemical Technology, 99%;

[0034] NH4H2PO4: Wuhan Chujiang Haoyu Chemical Technology, 99%;

[0035] Urea: Shandong Junguan Chemical Co., Ltd.

[0036] Carboxylated multi-walled carbon nanotubes: Suzhou Kaifa New Materials Technology;

[0037] Phenolic resin: Hubei Qibajiu Chemical Co., Ltd., type 2123, solid flakes and powder.

[0038] The present invention provides the following embodiments and comparative examples, and conducts experimental verification to demonstrate the beneficial effects of the present invention.

[0039] Example 1

[0040] S1. Place 22.5 parts NiSO4·6H2O, 3 parts CoSO4·7H2O, and 1.8 parts MnSO4·H2O in 50 parts deionized water, dissolve evenly, and prepare a metal salt solution containing nickel, cobalt, and manganese for later use.

[0041] Prepare a 2.0 mol / L NaOH solution for later use;

[0042] Prepare a 0.5 mol / L NH3·H2O solution for later use;

[0043] Place 0.2 parts LiNO3, 0.13 parts NH4H2PO4, and 0.05 parts urea in 20 parts deionized water, mix well, and prepare a precursor solution for later use.

[0044] S2. Under nitrogen protection, the metal salt solution containing nickel, cobalt and manganese, along with NaOH solution and NH3·H2O solution, are added to the batch reactor in a mass ratio of 5:10:5. The pH is controlled at 11.4. After adding the materials, the mixture is aged, washed, and dried at 90℃ to synthesize dense spherical NCM.

[0045] S3. NCM, LiOH·H2O and LiF are mixed in a mass ratio of 9:4.5:0.08. Anhydrous ethanol is added and the mixture is ball-milled until uniform. After drying, the mixture is sintered in an oxygen atmosphere. The temperature is first raised to 500℃ for 5 hours, then raised to 750℃ for 10 hours, and then raised to 880℃ for 10 hours. The mixture is then cooled in the furnace to obtain fluorine-doped NCM powder.

[0046] S4. The precursor solution and fluorine-doped NCM powder were placed in a reactor at a mass ratio of 0.1:10. The precursor solution was uniformly loaded onto the surface of the fluorine-doped NCM powder by rotary evaporation. After drying, the powder was heat-treated in an argon atmosphere. The temperature was first raised to 350℃ and held for 2 hours, and then raised to 600℃ and treated for 5 hours. After cooling, LiPON-coated fluorine-doped NCM composite material was obtained.

[0047] S5. Disperse 0.15 parts of carboxylated multi-walled carbon nanotubes, 9 parts of LiPON-coated fluorine-doped NCM composite material, and 0.5 parts of phenolic resin in 100 parts of anhydrous ethanol, evaporate and dry, carbonize in an argon atmosphere, first heat to 350℃ for pre-curing for 1 hour, then heat to 650℃ for carbonization treatment for 2 hours, cool and grind, and sieve through 400 mesh to obtain the cathode material.

[0048] Example 2

[0049] S1. Dissolve 25 parts NiSO4·6H2O, 3 parts CoSO4·7H2O, and 1.7 parts MnSO4·H2O in 55 parts deionized water until homogeneous to prepare a metal salt solution containing nickel, cobalt, and manganese for later use.

[0050] Prepare a 2.2 mol / L NaOH solution for later use;

[0051] Prepare a 0.6 mol / L NH3·H2O solution for later use;

[0052] 0.22 parts LiNO3, 0.13 parts NH4H2PO4, and 0.03 parts urea were placed in 22 parts deionized water, mixed thoroughly, and a precursor solution was prepared for later use.

[0053] S2. Under nitrogen protection, the metal salt solution containing nickel, cobalt and manganese, along with NaOH solution and NH3·H2O solution, are added to the batch reactor in a mass ratio of 6:11:6. The pH is controlled at 11.6. After adding the materials, the mixture is aged, washed, and dried at 100℃ to synthesize dense spherical NCM.

[0054] S3. NCM, LiOH·H2O and LiF are mixed in a mass ratio of 10:5:0.09, anhydrous ethanol is added and ball-milled evenly. After drying, the mixture is sintered in an oxygen atmosphere. The temperature is first raised to 520℃ for 6 hours, then raised to 770℃ for 11 hours, and then raised to 890℃ for 11 hours. The mixture is then cooled in the furnace to obtain fluorine-doped NCM powder.

[0055] S4. The precursor solution and fluorine-doped NCM powder were placed in a reactor at a mass ratio of 0.2:10. The precursor solution was uniformly loaded onto the surface of the fluorine-doped NCM powder by rotary evaporation. After drying, the powder was heat-treated in an argon atmosphere. The temperature was first raised to 370℃ and held for 3 hours, and then raised to 620℃ and treated for 6 hours. After cooling, LiPON-coated fluorine-doped NCM composite material was obtained.

[0056] S5. Disperse 0.17 parts of carboxylated multi-walled carbon nanotubes, 9 parts of LiPON-coated fluorine-doped NCM composite material, and 0.3 parts of phenolic resin in 105 parts of anhydrous ethanol, evaporate and dry, and carbonize in an argon atmosphere. First, heat to 370℃ for pre-curing for 1.5 h, then heat to 670℃ for carbonization treatment for 2.5 h. After cooling, grind and sieve through 400 mesh to obtain the cathode material.

[0057] Example 3

[0058] S1. Place 22.5 parts NiSO4·6H2O, 4 parts CoSO4·7H2O, and 1.7 parts MnSO4·H2O in 53 parts deionized water, dissolve evenly, and prepare a metal salt solution containing nickel, cobalt, and manganese for later use.

[0059] Prepare a 2.1 mol / L NaOH solution for later use;

[0060] Prepare a 0.55 mol / L NH3·H2O solution for later use;

[0061] Place 0.2 parts LiNO3, 0.15 parts NH4H2PO4, and 0.03 parts urea in 21 parts deionized water, mix well, and prepare a precursor solution for later use.

[0062] S2. Under nitrogen protection, the metal salt solution containing nickel, cobalt and manganese, along with NaOH solution and NH3·H2O solution, are added to the batch reactor in a mass ratio of 6:10:5. The pH is controlled at 11.5. After adding the materials, the mixture is aged, washed, and dried at 95°C to synthesize dense spherical NCM.

[0063] S3. NCM, LiOH·H2O and LiF are mixed in a mass ratio of 10:4.5:0.08. Anhydrous ethanol is added and the mixture is ball-milled until uniform. After drying, the mixture is sintered in an oxygen atmosphere. The temperature is first raised to 510℃ for 5.5h, then raised to 760℃ for 10.5h, and then raised to 885℃ for 10.5h. The mixture is then cooled in the furnace to obtain fluorine-doped NCM powder.

[0064] S4. The precursor solution and fluorine-doped NCM powder were placed in a reactor at a mass ratio of 0.15:10. The precursor solution was uniformly loaded onto the surface of the fluorine-doped NCM powder by rotary evaporation. After drying, the powder was heat-treated in an argon atmosphere. The temperature was first raised to 360℃ and held for 2 hours, and then raised to 610℃ and treated for 5 hours. After cooling, LiPON-coated fluorine-doped NCM composite material was obtained.

[0065] S5. Disperse 0.16 parts of carboxylated multi-walled carbon nanotubes, 9.5 parts of LiPON-coated fluorine-doped NCM composite material, and 0.4 parts of phenolic resin in 103 parts of anhydrous ethanol, evaporate and dry, and carbonize in an argon atmosphere. First, heat to 360℃ for pre-curing for 1.2 h, then heat to 660℃ for carbonization treatment for 2.5 h. After cooling, grind and sieve through 400 mesh to obtain the cathode material.

[0066] Comparative Example 1

[0067] S1. Place 22.5 parts NiSO4·6H2O, 3 parts CoSO4·7H2O, and 1.8 parts MnSO4·H2O in 50 parts deionized water, dissolve evenly, and prepare a metal salt solution containing nickel, cobalt, and manganese for later use.

[0068] Prepare a 2.0 mol / L NaOH solution for later use;

[0069] Prepare a 0.5 mol / L NH3·H2O solution for later use;

[0070] S2. Under nitrogen protection, the metal salt solution containing nickel, cobalt and manganese, along with NaOH solution and NH3·H2O solution, are added to the batch reactor in a mass ratio of 5:10:5. The pH is controlled at 11.4. After adding the materials, the mixture is aged, washed, and dried at 90℃ to synthesize dense spherical NCM.

[0071] S3. Mix NCM and LiOH·H2O at a mass ratio of 2:1, add anhydrous ethanol and ball mill evenly, dry and sinter in an oxygen atmosphere, first heat to 500℃ for 5h, then heat to 750℃ for 10h, then heat to 880℃ for 10h, cool with furnace, grind the sintered block and sieve through 400 mesh to obtain the cathode material.

[0072] The cathode materials obtained in Examples 1-3 and Comparative Example 1 were used to prepare batteries for testing.

[0073] The battery fabrication process is as follows: Positive electrode material, conductive agent (SP), and PVDF are dissolved in N-methylpyrrolidone (NMP) at a mass ratio of 94:3:3 to form a slurry. This slurry is then coated onto aluminum foil using an automated coating machine. After vacuum drying for 12 hours, it is cut into positive electrode sheets; the negative electrode is a lithium sheet; the electrolyte is 1 mol / L LiPF6 + EC + EMC; and the separator is a polyethylene / propylene composite microporous membrane. All materials are then assembled into coin cells under standard process conditions.

[0074] The electrochemical performance of each group of batteries was tested on the Wuhan Landian CT2001A battery tester.

[0075] At 25°C, within a voltage window of 2.8–4.3V, the first charge and discharge were performed with a current of 0.1C, and the first discharge specific capacity and the first coulombic efficiency were recorded.

[0076] Ratio testing: Cycle at 0.2C for 2 weeks, then cycle at 0.5C, 1C, 2C, and 5C for 5 weeks each, and finally return to 0.2C for 5 weeks to examine the capacity recovery rate.

[0077] Low-temperature performance test: The battery was placed in a -20℃ constant temperature chamber and left to stand for more than 4 hours to ensure temperature uniformity. At -20℃, it was charged and discharged three times at 0.2C, and the discharge capacity after stabilization was recorded. The ratio of the discharge capacity at -20℃ to the reference capacity at 25℃ was calculated, i.e., the low-temperature capacity retention rate.

[0078] Long-cycle test: At 25℃, 1C rate, and 2.8-4.3V, continuous constant current charge-discharge cycles were performed for 500 cycles, and the capacity retention rate was recorded.

[0079] The battery performance test results are shown in the table below:

[0080]

[0081] Based on the above test results, it can be seen that Embodiments 1-3 of the present invention have excellent effects in all tests, with excellent high-rate and low-temperature performance and significantly improved cycle life.

[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a lithium ion battery cathode material with high interfacial conductance, characterized in that, The steps include: Step one, under the protection of nitrogen, the metal salt solution containing nickel, cobalt and manganese is placed in the intermittent reactor with precipitator and complexing agent, and then aged, washed and dried to obtain spherical NCM; Step two, the NCM obtained in step one, LiOH·H2O and LiF are uniformly ball milled with anhydrous ethanol, dried and sintered in an oxygen atmosphere, and then cooled in the furnace to obtain fluorine-doped NCM powder; the mass ratio of NCM, LiOH·H2O and LiF is (9-10):(4.5-5):(0.08-0.09); Step three, LiNO3, NH4H2PO4, urea and deionized water are mixed to prepare a precursor solution, which is uniformly loaded on the fluorine-doped NCM powder obtained in step two by rotary evaporation, and then dried and heat treated in an argon atmosphere to obtain LiPON-coated fluorine-doped NCM composite material; the mass ratio of the precursor solution to the fluorine-doped NCM powder is (0.1-0.2):10; Step four, the carboxylated multi-walled carbon nanotubes are dispersed in anhydrous ethanol, and the LiPON-coated fluorine-doped NCM composite material obtained in step three and phenolic resin are added, and then evaporated and dried, carbonized in an argon atmosphere, and ground and sieved after cooling to obtain a positive electrode material.

2. The method of claim 1, wherein the lithium ion battery cathode material is prepared by the steps of: The preparation steps of the metal salt solution containing nickel, cobalt and manganese in step one include: 22.5-25 parts of NiSO4·6H2O, 3-4 parts of CoSO4·7H2O and 1.7-1.8 parts of MnSO4·H2O are placed in 50-55 parts of deionized water and dissolved uniformly. ​ The precipitator is a 2.0-2.2 mol / L NaOH solution, and the complexing agent is a 0.5-0.6 mol / L NH3·H2O solution; the mass ratio of the metal salt solution containing nickel, cobalt and manganese to the precipitator and the complexing agent is (5-6):(10-11):(5-6).

3. The method for preparing lithium-ion battery cathode material according to claim 1, characterized in that, The operating temperature in step one is 55-60℃, and the pH is controlled at 11.4-11.

6.

4. The method for preparing lithium-ion battery cathode material according to claim 1, characterized in that, The sintering in the oxygen atmosphere in step two includes first treating at 500-520℃ for 5-6h, then raising the temperature to 750-770℃ for 10-11h, and then raising the temperature to 880-890℃ for 10-11h.

5. The method for preparing lithium-ion battery cathode material according to claim 1, characterized in that, The preparation steps of the precursor solution in step three include: 0.2-0.22 parts of LiNO3, 0.13-0.15 parts of NH4H2PO4 and 0.03-0.05 parts of urea are placed in 20-22 parts of deionized water and mixed uniformly.

6. The method for preparing lithium-ion battery cathode material according to claim 1, characterized in that, The heat treatment in the argon atmosphere in step three includes first heat treatment at 350-370℃ for 2-3h, and then heat treatment at 600-620℃ for 5-6h.

7. The method for preparing lithium-ion battery cathode material according to claim 1, characterized in that, In step four, 0.15-0.17 parts of carboxylated multi-walled carbon nanotubes, 9-10 parts of LiPON-coated fluorine-doped NCM composite material and 0.3-0.5 parts of phenolic resin are dispersed in 100-105 parts of anhydrous ethanol.

8. The method for preparing lithium-ion battery cathode material according to claim 1, characterized in that, The carbonization in step four under argon atmosphere comprises pre-curing at 350-370 DEG C for 1-1.5 hours, and then carbonization treatment at 650-670 DEG C for 2-2.5 hours.

9. A high interfacial conductance lithium-ion battery cathode material, characterized in that, The lithium ion battery cathode material is prepared by the method according to any one of claims 1-8.

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