Preparation method of high-stable slurry of conductive agent composite active material

Abstract

The application provides a preparation method of high-stable slurry of active material compounded with conductive agent. The preparation method comprises the following steps: (1) adding conductive agent in a solvent thermal reaction process to prepare a precursor; (2) drying the precursor in step (1) and then annealing under an inert atmosphere to obtain an active composite material; and (3) mechanically dispersing the active composite material in step (2) and conductive additive in an electrolyte to obtain a composite slurry capable of running under a large current density. By compounding the conductive agent with high conductivity and the active material, the conductivity of the material is improved, the dispersion state of solid particles in the slurry is improved, the stable and efficient percolation conductive network is formed in the interior of the slurry electrode, and the stability and electrochemical performance of the slurry are enhanced. The preparation method is simple and easy to implement, and is conducive to realizing the large-scale application of the slurry battery under a large current density.

Description

Technical Field

[0001] This invention belongs to the field of lithium slurry batteries, specifically relating to a method for modifying a composite active material with a suitable conductive agent under high current density and a method for preparing a highly stable slurry. Background Technology

[0002] To overcome energy challenges and promote energy transition, lithium slurry batteries have attracted widespread attention as a novel large-scale energy storage technology. Unlike traditional lithium-ion batteries, lithium slurry batteries disperse commonly used active materials and conductive additives together in an electrolyte to form positive and negative electrode slurries. These slurries are then transported to an electrochemical reactor via an external pump to undergo an electrochemical reaction, thereby achieving energy conversion and storage. Therefore, lithium slurry batteries can decouple energy and power, possessing enormous potential for large-scale energy storage applications. The active material, as a crucial component of the slurry battery, plays a vital role in the performance of the slurry electrode due to its morphology, content, and conductivity. Modifying the active material can effectively improve the electron-ion transfer efficiency within the slurry electrode, fully leveraging its lithium storage capacity and constructing a highly stable and high-capacity negative electrode slurry. Currently, researchers are conducting studies on active material modification and slurry preparation process optimization.

[0003] CN1113054196A discloses a method for modifying the positive electrode active material of a lithium slurry battery. First, a concentration-gradient nickel-cobalt-manganese ternary material is prepared, which is then surface-modified with a silane coupling agent and grafted with an ionic liquid, followed by coating with porous graphene. This modification method uses ionic liquids as linkers to connect the graphene coating layer, ensuring the excellent performance of the active material. However, this process is complex, and ionic liquids are expensive, making it difficult to meet the low-cost requirements of large-scale energy storage.

[0004] CN115275157A discloses a lithium slurry battery anode active material and its preparation method. A silicon-oxygen material with both carbon coating and carbon-reduced silicon dioxide was prepared using a sol-gel-hydrothermal method and high-temperature heat treatment, and used as the active material for the slurry electrode. The modification strategy effectively improves the surface adhesion and interfacial compatibility of the material, while promoting localized force release to alleviate volume expansion and particle breakage problems during silicon charging and discharging, ensuring the formation of a stable solid electrolyte interface and enhancing lithium-ion kinetic diffusion. However, the modification process involves harsh acidic conditions, introducing additional requirements for equipment; and the process flow is too long, reducing production efficiency.

[0005] CN110165157B discloses a method for uniformly mixing a lithium titanate slurry containing carbon nanotubes. The process includes adding a binder to an electrolyte to prepare a gel, then adding carbon nanotubes to prepare a conductive gel, and finally mixing the conductive agent and the main material (forming a mixed dry material) with the conductive gel to prepare the lithium titanate slurry containing carbon nanotubes. This preparation method represents a strategy for preparing lithium-ion battery slurries, ensuring thorough mixing and providing important guidance for the fabrication process of lithium slurry electrodes.

[0006] Therefore, there is a need in this field for a novel strategy to modify the active material of lithium slurry electrodes, to prepare slurry electrodes with high-efficiency ion-electron transfer, enabling them to operate at high current densities and exhibit good electrochemical performance. Simultaneously, the preparation process should be simple and cost-effective. Summary of the Invention

[0007] To address the shortcomings of existing technologies, one objective of this invention is to provide a novel modification strategy for lithium slurry electrode active materials. The strategy involves combining the active material with a conductive additive to improve the material's conductivity. The uncomposite, exposed conductive additive can disperse with the active material in the electrolyte to form a permeable conductive network, enhancing ion-electron transfer within the electrode. The active material is bronze-phase titanium dioxide (TiO2(B)); the conductive agent is one or a combination of two or more of conductive carbon black (Surper P), Ketjen black (KB), single-walled carbon nanotubes (SWCNT), multi-walled carbon nanotubes (MWCNT), carbon nanofibers (CNF), reduced graphene oxide (rGO), and graphene (GO). The electrolyte consists of a lithium salt and a solvent; the lithium salt is one or a combination of two or more of LiPF6, LiTFSI, LiBOB, and LiDFOB, with a molar concentration of 1-3 mol / L in the electrolyte; the solvent is at least one of carbonate, ether, and carboxylic acid ester.

[0008] The active material accounts for 5% to 55% of the mass of the slurry; the conductive agent accounts for 0% to 2% of the mass of the slurry; and the sum of the mass percentages of the active material, conductive agent, and electrolyte is 100%.

[0009] The modification strategies described in this invention include, but are not limited to, growing active materials on a conductive additive matrix; and coating active materials with conductive additives to form a conductive carbon layer. Combining active materials with conductive additives can effectively improve the conductivity of electrode materials. Uncombined, exposed conductive additives can, together with additional conductive additives added during slurry preparation (optional), form an electrode permeation conductive network, thereby strengthening the ion and electron transport pathways within the electrode and improving its electrochemical performance.

[0010] A second objective of this invention is to provide a preparation process for a modified slurry of an active material composite conductive additive, wherein the active material is bronze-phase titanium dioxide (TiO2(B)). The raw materials used in this invention are widely available, and the preparation process is simple and easy to control, which is beneficial for meeting the production needs of large-scale energy storage. The preparation method includes the following steps:

[0011] 1. The modification method is a solvothermal method, in which an aqueous solution of conductive additive is added during the solvothermal reaction.

[0012] 2. Titanate composite precursors are grown on the surface of conductive additives via a traditional solvothermal reaction.

[0013] 3. Anneal the titanate composite precursor under an inert atmosphere to obtain a bronze phase titanium dioxide composite material.

[0014] 4. A negative electrode composite slurry for high current density applications is constructed by mechanically dispersing bronze phase titanium dioxide composite material and additional conductive additives in an electrolyte.

[0015] Preferably, the conductive additive used in the composite process is one or a combination of two or more of the following: aqueous solution of single-walled carbon nanotubes, aqueous solution of reduced graphene oxide, and aqueous solution of graphene oxide, with a mass fraction of 0.1 to 10 wt%, for example, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, or 10 wt%.

[0016] Preferably, the organic solvent for the solvothermal reaction is ethanol, ethylene glycol, or glycerol, etc.

[0017] Preferably, the titanium source material is a titanium trichloride solution and / or a titanium tetrachloride solution, etc.

[0018] Preferably, titanium trichloride solution, deionized water, and an aqueous solution of conductive additives are uniformly dissolved in an organic solution to carry out a solvothermal reaction.

[0019] Preferably, the total volume ratio of the conductive additive aqueous solution and the deionized water to the titanium trichloride solution is 0.1 to 1.5, for example, it can be 0.1, 0.2, 0.5, 0.8, 1.0, 1.25 or 1.5.

[0020] Preferably, the volume ratio of titanium trichloride solution to organic solution is 1:15 to 2:15, for example, it can be 1:15, 1.5:15 or 2:15, etc.

[0021] Preferably, the dispersion process involves first mixing a deionized aqueous solution and a conductive additive aqueous solution to obtain a carbon-based solution 1; then uniformly dispersing the solution using either ultrasonic or mechanical stirring. The mixing and dispersion time is 1 to 4 hours, for example, 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours, or 4 hours.

[0022] Preferably, the carbon-based solution 1 is dispersed in an organic solvent to obtain a mixed solution 2. The selected mixing method is any one or a combination of multiple methods such as ultrasonic or mechanical mixing, and the mixing time is 1 to 4 hours.

[0023] Preferably, the titanium source material solution is added to an organic solvent to obtain mixed solution 2. The selected mixing method is any one or a combination of multiple methods such as ultrasonic and mechanical mixing, and the mixing time is 1~4 hours.

[0024] Preferably, the solvent is transferred to a reaction vessel for reaction, ensuring that the vessel is filled with 10-60% of its volume, for example, 10%, 20%, 30%, 40%, 50% or 60%.

[0025] Preferably, the temperature of the solvothermal reaction process is controlled at 120~180℃, for example, 120℃, 130℃, 140℃, 150℃, 160℃, 170℃ or 180℃; the reaction time is 3~24h, for example, 3h, 6h, 9h, 12h, 15h, 18h, 21h or 24h.

[0026] Preferably, after the solvothermal reaction process is completed and cooled to room temperature, solid 1 is obtained by filtration or centrifugation. The centrifugation rate is 5000~10000 r / min, for example, 5000 r / min, 6000 r / min, 7000 r / min, 7000 r / min, 8000 r / min, 9000 r / min or 10000 r / min, etc., and the centrifugation time is 1~15 min, for example, 1 min, 2 min, 3 min, 4 min, 5 min, 6 min, 7 min, 8 min, 9 min, 10 min, 11 min, 12 min, 13 min, 14 min or 15 min, etc.

[0027] Preferably, solid 1 is washed with ethanol and water multiple times, and solid 2 is obtained by centrifugation or filtration.

[0028] Preferably, solid 2 is dried to obtain a titanate composite conductive additive precursor. The drying is performed by forced-air drying or vacuum drying.

[0029] Preferably, the drying temperature is 50~80℃, for example, it can be 50℃, 55℃, 60℃, 65℃, 70℃, 75℃ or 80℃, etc., and the drying time is 24~72h, for example, it can be 24h, 25h, 26h, 28h, 30h, 35h, 40h, 45h, 50h, 55h, 60h, 65h, 70h or 72h, etc.

[0030] Preferably, the titanate precursor is annealed to obtain the active composite material.

[0031] Preferably, the annealing environment is an inert atmosphere, such as a nitrogen atmosphere or an argon atmosphere.

[0032] Preferably, the heating rate of the annealing process is 1-15℃ / min, for example, it can be 1℃ / min, 2℃ / min, 3℃ / min, 4℃ / min, 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, 9℃ / min, 10℃ / min, 11℃ / min, 12℃ / min, 13℃ / min, 14℃ / min or 15℃ / min.

[0033] Preferably, the annealing process is maintained at a constant temperature of 200~400℃, for example, 200℃, 250℃, 300℃, 350℃ or 400℃.

[0034] Preferably, the annealing process is maintained at a constant temperature for 10 to 480 minutes, for example, 10 minutes, 30 minutes, 60 minutes, 120 minutes, 180 minutes, 240 minutes, 300 minutes, 360 minutes, 420 minutes, or 480 minutes.

[0035] Preferably, in step 4, the active composite material and conductive additives are dispersed into the electrolyte to obtain the negative electrode composite slurry.

[0036] Preferably, the mass fraction of the active composite material is 5-55%, for example, it can be 5%, 15%, 25%, 35%, 45% or 55%.

[0037] Preferably, the mass fraction of the conductive additive is 0.1-2%, for example, it can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.8%, 1.0%, 1.2%, 1.4%, 1.6%, 1.8% or 2.0%, etc.

[0038] Preferably, the mixing method is one or a combination of mechanical mixing, ultrasonic mixing, etc.; the mixing time is 0.5 to 4 hours, for example, it can be 0.5 hours, 1.0 hours, 1.5 hours, 2.0 hours, 2.5 hours, 3.0 hours, 3.5 hours or 4.0 hours.

[0039] The preparation method described in this invention improves the conductivity and ion conduction of the active material, fully utilizing its electrochemical performance. The composite and additional conductive additives together form a robust and efficient percolation conductive network, reducing the sedimentation rate of active substances in the slurry, fully stabilizing the slurry, and forming a highly stable slurry electrode. By combining with highly conductive additives, the amount of additional conductive additives is reduced while ensuring the conductivity of the slurry, thereby increasing the limit of active substance loading in the slurry electrode and further meeting the volumetric capacity requirements of large-scale energy storage.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] (1) The modification strategy of active material composite conductive additive adopted in this invention can improve the conductivity of electrode material and ensure the formation of a highly efficient permeation conductive network inside the slurry electrode. At the same time, it can accelerate the diffusion of lithium ions inside the slurry electrode, improve the interfacial electrochemical reaction kinetics, and give full play to the electrochemical performance of the active material.

[0042] (2) The modification strategy of the present invention enables more sufficient contact between the active material and the conductive additive, alleviates the sedimentation of the active material, and significantly improves the stability of the slurry. On the basis of ensuring sufficient electron conduction pathways, the amount of additional conductive additives added to the slurry can be reduced, which can correspondingly increase the loading of the active material, increase the volumetric energy density of the slurry, and meet the needs of large-scale energy storage.

[0043] (3) The improved process of the present invention involves introducing conductive additives during the solvothermal synthesis of the material. The process is simple and highly feasible. At the same time, the process conditions are mild and the process is easy to control, meeting the needs of large-scale production. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the negative electrode slurry prepared using the active composite material proposed in this invention.

[0045] Figure 2 This is a SEM image of the active composite material prepared in Specific Embodiment 1 of the present invention.

[0046] Figure 3 This is a TEM image of the active composite material prepared in Specific Embodiment 1 of the present invention.

[0047] Figure 4 This is the BET diagram of the active composite material prepared in Specific Embodiment 1 of the present invention.

[0048] Figure 5 It is the yield stress of the active composite material prepared in Specific Embodiment 1 of the present invention.

[0049] Figure 6 This is an electrochemical performance diagram of the active composite material slurry prepared according to specific embodiment 1 of the present invention. Detailed Implementation

[0050] To provide a detailed description of the present invention and to facilitate the reader's understanding of its application, the following specific embodiments are listed as exemplary illustrations of the present invention. Those skilled in the art should understand that the embodiments are merely illustrative and should not be considered as specific limitations on the present invention.

[0051] Example 1

[0052] A composite conductive additive slurry containing active materials (illustrated in the figure) Figure 1 The preparation process of ) is carried out at room temperature, and the process is as follows:

[0053] (1) Mix 1 mL of single-walled carbon nanotube solution (mass fraction 0.2 wt%) and 1 mL of deionized water solution and sonicate for 2 h. Add the mixture dropwise to 30 mL of ethylene glycol solution and stir for 2 h to obtain mixed solution 1. Add 2 mL of titanium trichloride solution dropwise to mixed solution 1 and stir for 2 h to obtain mixed solution 2. Transfer the above mixed solution 2 to a 100 mL reaction vessel and place it in a forced-air oven at 150 °C for 6 h. After the reaction is completed and cooled to room temperature, centrifuge at 8000 r / min for 10 min each time. Wash with ethanol and water several times in sequence and centrifuge to obtain a gray-black solid mixture. Dry it in a vacuum oven at 60 °C for 12 h to obtain the titanate composite carbon nanotube precursor.

[0054] (2) The titanate composite precursor obtained in step 1 was annealed in a tube furnace under a high-purity argon atmosphere. The annealing heating rate was 3℃ / min, and the temperature was raised to 350℃. The annealing process was maintained at 350℃ for 0.5h, and then naturally cooled to room temperature. The annealed solid was thoroughly ground to obtain the active composite material A.

[0055] (3) Prepare a slurry by mixing active composite material A, conductive additive KB, and electrolyte in a mass ratio of 15:1:84. First, add KB to the electrolyte and mix for 2 hours using a planetary mixer to obtain suspension 1. Then, add active composite material A in proportion and mix for 2 hours using a planetary mixer to obtain active composite material slurry.

[0056] The SEM image of the active composite material prepared in this embodiment is shown below. Figure 2 As shown, from Figure 2It can be seen that the nano-active materials grow along single-walled carbon nanotubes, the CNTs are relatively uniformly dispersed, and the material morphology is diverse, including uniform nanoflower structures, nanorod structures growing along single-walled carbon nanotubes, and exposed carbon nanotubes not coated by the nano-active materials; its TEM image is shown below. Figure 3 As shown, from Figure 3 This can further verify that the nano-active materials and carbon nanotubes form a good composite, rather than a simple mechanical mixing effect; Figure 4 The BET plot of the active composite material in this embodiment shows that the specific surface area of ​​the material is significantly increased after composite modification, and the contact between the active composite material and the electrolyte is more complete. Figure 5 The shear rheological behavior shows that the composite modification significantly improves the yield stress of the slurry and significantly enhances its stability.

[0057] Example 2

[0058] The difference from Example 1 is that the conductive additive solution in step (1) is a reduced graphene oxide solution (mass fraction of 0.2wt%) with a volume of 1mL.

[0059] Example 3

[0060] The difference from Example 1 is that the conductive additive solution in step (1) is 0.5 mL of reduced graphene oxide solution (mass fraction of 0.2 wt%) and 0.5 mL of single-walled carbon nanotube solution (mass fraction of 0.2 wt%).

[0061] Example 4

[0062] The difference from Example 1 is that the conductive additive in step (3) is reduced graphene oxide.

[0063] Example 5

[0064] The difference from Example 1 is that the conductive additive in step (3) is carbon nanofiber.

[0065] Example 6

[0066] The difference from Example 1 is that no additional conductive additives are added in step (3). The mass percentage of active composite material and electrolyte in the slurry is 25:75.

[0067] Comparative Example 1

[0068] The difference from Example 1 is that the single-walled carbon nanotube solution in step (1) is 0 mL and the deionized water is 2 mL.

[0069] Comparative Example 2

[0070] The difference from Example 1 is that the active material in step (3) is the sample obtained in Comparative Example 1, and the conductive additive is single-walled carbon nanotubes.

[0071] Comparative Example 3

[0072] The difference from Example 1 is that the annealing process in step (2) is maintained at a constant temperature of 300°C.

[0073] Comparative Example 4

[0074] The difference from Example 1 is that in step (3), the mass fraction of the active composite material is 5%, the mass fraction of the conductive additive is 1%, and the mass fraction of the electrolyte is 89%.

[0075] The prepared active composite material slurry was subjected to the following electrochemical performance tests:

[0076] (1) Assembly of lithium slurry batteries: Conductive carbon cloth is cut into circular pieces with a diameter of 14 mm to be used as the load for the slurry electrode. The prepared slurry is uniformly coated onto the carbon cloth and weighed to ensure that the loading of active material is 1.5~2 g / cm³. 2 Then, it is assembled into a coin cell with a Celgard 2325 separator (16 mm in diameter) and a lithium sheet (15.8 mm in diameter and 0.5 mm thick). The assembly of the lithium slurry reactor cell is similar to that of the coin cell; the dimensions of the carbon cloth and separator need to be designed according to the reactor's flow channels. All assembly processes must be carried out in an argon-filled glove box.

[0077] (2) Energy density test: Constant current charge-discharge test was conducted using a battery meter. The charging cutoff voltage was 3.0V, and the discharging cutoff voltage was 1.0V. After two cycles of activation at 0.01C, the battery's cycle performance and coulombic efficiency were tested at a current density of 0.5C. The battery was cycled 100 times at 0.5C, and the capacity decay rate for each cycle was calculated. High current density cycling was performed at a current density of 2C.

[0078] Table 1

[0079] <![CDATA[Specific capacity (mAh g -1 )]]> Coulomb efficiency (%) <![CDATA[Capacity attenuation rate (mAh g -1 / cycle) <!-- 5 -->]]> Example 1 277.8 99.8 6.3 Example 2 267.6 98.6 5.9 Example 3 282.4 99.7 4.6 Example 4 265.8 99.4 6.9 Example 5 256.1 97.9 6.7 Example 6 220.8 95.6 8.4 Comparative Example 1 247.9 99.3 8.2 Comparative Example 2 268.5 99.6 7.4 Comparative Example 3 264.5 98.6 7.7 Comparative Example 4 263.1 98.4 6.5

[0080] As shown in Table 1, compared to Comparative Example 1, Examples 1 to 5, tested at a current density of 0.5C, exhibited lower cycle specific capacity, coulombic efficiency, and capacity decay rate of the slurry electrode, indicating that the composite modification significantly improved the cycle stability of the slurry and resulted in superior electrochemical performance. At a current density of 2C, Example 1 achieved a capacity of 173.7 mAh g⁻¹ after 500 cycles. -1 The capacity retention rate is 78.8% (e.g., Figure 6This can be attributed to the significant increase in conductivity of the active material when combined with a highly conductive material.

[0081] As shown in Table 1, at a current density of 0.5C, Example 3 exhibits higher specific capacity and cycle stability than Examples 1 and 2. The performance of the active material composited with two-dimensional conductive additives (reduced graphene oxide and single-walled carbon nanotubes) is superior to that modified with a single-dimensional conductive agent. This can be attributed to the fact that multi-dimensional conductive agents fully utilize the synergistic effect between conductors of different dimensions, forming a multi-dimensional conductive network that complements each other, allowing for sufficient contact between the conductive agent and the active material, thereby improving conductivity. Multi-dimensional conductive agents are also more conducive to the uniform growth of the active material on the conductive agent, fully utilizing the material's lithium storage capacity.

[0082] As shown in Table 1, compared to Example 1, the circulation capacity, coulombic efficiency, and stability of the slurry in Examples 4-5 were all reduced at a current density of 0.5C. This indicates that the morphology of the additional conductive additive, at the same content, has a significant impact on the slurry performance. The percolation threshold of the slurry changes when additional conductive additives with different morphologies are introduced, requiring further investigation.

[0083] As shown in Table 1, compared to Example 1, Example 6 exhibits reduced cycle capacity and stability at a current density of 0.5C. The slurry in Example 6 did not contain any additional conductive additives; consequently, the mass percentage of the active composite material increased to 25%. Although some capacity was lost, the effect on increasing the loading of active materials in the slurry was significant, demonstrating substantial practical value.

[0084] As shown in Table 1, compared to Example 1, Comparative Examples 1 and 2 exhibited lower cyclic specific capacity and capacity decay rate at a current density of 0.5C. This indicates that the composite modification of the active material using conductive agents differs from the simple mechanical mixing during slurry preparation. The composite-modified conductive additives, acting as conductors to improve the conductivity of the material, also serve as an important component of the percolation conductive network in the slurry, providing an efficient and robust electronic conduction pathway.

[0085] As can be seen from Table 1, compared with Example 1, Comparative Example 3 showed a decrease in specific capacity and cycle stability of the slurry at a current density of 0.5C, indicating that optimizing the synthesis process parameters of the active material has an important impact on improving the performance of the material.

[0086] As shown in Table 1, compared to Example 6, Comparative Example 4 exhibits lower cycle capacity and stability at a current density of 0.5C. This indicates a reduced content of active materials in the slurry, preventing the formation of interconnected conductive networks, resulting in lower utilization of active materials and limited electrochemical performance. The content and morphology of active materials and conductive agents significantly affect the slurry's performance, necessitating further optimization for slurry development.

[0087] The applicant declares that the detailed process flow of this invention is illustrated by the above embodiments, but this invention is not limited to the above detailed process flow, that is, it does not mean that this invention must rely on the above process flow to be implemented. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of raw materials for the product of this invention, additions of auxiliary components, and selection of specific methods, all fall within the protection and disclosure scope of this invention.

Claims

1. A method for preparing a high-stability slurry of a complex active material with a suitable conductive agent, characterized by, The preparation method includes: (1) A titanate precursor is grown on the surface of a conductive agent by a solvothermal reaction. The solvothermal reaction steps are as follows: first, a deionized aqueous solution and a conductive additive aqueous solution are mixed to obtain a carbon-based solution 1; the carbon-based solution 1 is dispersed in an organic solvent to obtain a mixed solution 2; a titanium source material solution is added to the mixed solution 2; the conductive additive aqueous solution is one or more of a single-walled carbon nanotube aqueous solution, a reduced graphene oxide aqueous solution, and a graphene oxide aqueous solution, with a mass fraction of 0.1~10wt%; the solvothermal reaction is carried out at 150℃ for 6 hours to obtain a composite precursor. (2) The composite precursor described in step (1) is washed with water and ethanol several times, and then dried in an oven at 60°C for 12 hours. (3) Anneal the dried precursor described in step (2) under an inert atmosphere to obtain an active composite material. The annealing process is carried out in a tube furnace filled with argon gas, with a heating rate of 3℃ / min, a controlled temperature of 350℃, and a holding time of 30 minutes. (4) The active composite material and conductive additive from step (3) are uniformly dispersed in the electrolyte by mechanical mixing to obtain a composite slurry.

2. The production method according to claim 1, characterized by, The conductive additive mentioned in step (4) is one or more of the following: conductive carbon black Surper P, Ketjen black KB, single-walled carbon nanotubes SWCNT, multi-walled carbon nanotubes MWCNT, carbon nanofibers CNF, reduced graphene oxide rGO, and graphene GO. The mass fraction of the conductive additive is 0.1~2%.

3. The preparation method according to claim 1, characterized in that, In the solvothermal reaction process, ethylene glycol is used as the solvent, and titanium trichloride solution, conductive agent aqueous solution and deionized water are added; the total volume ratio of deionized water and conductive agent aqueous solution to titanium trichloride solution is 1:1, and the volume ratio of titanium trichloride solution to ethylene glycol solvent is 1:

15.

4. The preparation method according to claim 1, characterized in that, The electrolyte is composed of lithium salt, additives and solvent; The electrolyte solvent is a mixture of ethylene carbonate (EC) and dimethyl carbonate (DMC) in a mass ratio of 3:

7. The lithium salt is one or a combination of two or more of LiPF6, LiTFSI, LiBOB and LiDFOB, and its molar mass concentration in the electrolyte is 1~3 mol / L.

5. A highly stable slurry of conductive agent composite active material suitable for high current density, characterized in that, The slurry is prepared according to the preparation method described in claims 1-4.

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