Preparation method and application of lithium battery electrode material

Abstract

The invention discloses a preparation method and application of a lithium battery electrode material, and relates to the technical field of lithium batteries. The preparation method comprises the following steps: mixing biochar with tin chloride pentahydrate, cerium chloride heptahydrate, ammonium fluoride and urea, adding two-dimensional nano titanium carbide, and carrying out a hydrothermal method to obtain the active material. The active material is applied to a lithium battery electrode material and is ball-milled and mixed with a conductive agent and a binder to obtain slurry, the surface of a copper foil is coated with the slurry, a working electrode is prepared through heat treatment, and then the working electrode is assembled to obtain a lithium battery. Wherein the binder adopts a polymer solution obtained by grafting sodium alginate with acrylamide, a cross-linking agent is added into the slurry to improve the binding effect, and finally heat treatment carbonization is performed to convert the binder into a conductive material to synergistically improve the electrochemical performance of the lithium battery.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium batteries, and specifically to a preparation method and application of a lithium battery electrode material. Background Art

[0002] With the transformation of the global energy structure towards cleaner and more sustainable forms, new energy technologies (such as lithium-ion batteries, supercapacitors, etc.), as efficient energy storage devices, have been widely used in fields such as electric vehicles, renewable energy storage systems, and portable electronic devices. However, the current development of new energy technologies still faces many challenges, especially in the design and performance optimization of electrode materials, where it is urgent to break through the limitations of traditional materials.

[0003] Although traditional electrode materials (such as graphite anodes) have good cycle stability, their theoretical specific capacity is relatively low (372 mAh / g), making it difficult to meet the requirements of high-energy-density energy storage devices. At the same time, under the demand for high power density, the ion diffusion rate and conductivity of materials often become bottlenecks; moreover, traditional electrode materials (such as cobalt-based cathode materials) rely on scarce resources, are costly, and pose environmental pollution risks. In addition, the preparation processes of some materials are complex, energy-consuming, and difficult to meet the requirements of large-scale production. Currently, with the increasing demand for green technologies and sustainable development, researchers have turned their attention to carbon-rich and silicon-rich materials made from agricultural waste, forestry waste, etc. These materials have a porous structure, a high specific surface area, and rich surface chemical properties, and are expected to be transformed into high-performance lithium battery electrode materials, thereby reducing the cost of lithium batteries and realizing the recycling of resources.

[0004] Therefore, to solve the above problems, the present invention provides a preparation method and application of a lithium battery electrode material. Summary of the Invention

[0005] The purpose of the present invention is to provide a preparation method and application of a lithium battery electrode material to solve the problems raised in the prior art.

[0006] To achieve the above purpose, the present invention provides the following technical solutions: A preparation method of a lithium battery electrode material, characterized in that the electrode material is obtained by combining an electrode sheet and an active slurry coated on the surface of the electrode sheet.

[0007] Among them, the active slurry includes an active material, and the preparation steps are as follows: Step s1: Crush bamboo and rice husks to obtain bamboo powder and rice husk powder, immerse them in deionized water, add an activator, soak for 12 h, then filter and dry, and then perform pyrolytic carbonization. After carbonization, add hydrochloric acid, heat up to 80 - 100 °C, stir for 2 h, filter and wash, and then dry at 90 °C for 14 h to obtain porous biochar; Step s2: Add tin (II) chloride pentahydrate, cerium (III) chloride heptahydrate, ammonium fluoride, and urea into deionized water in sequence and mix them. Then add the porous biochar and two-dimensional titanium carbide nanosheets prepared in step s1, heat to 180 - 200 °C, keep warm for 24 h, wash with deionized water and then dry to obtain the active material.

[0008] Preferably, the process parameters of pyrolytic carbonization in step s1 are: heat up to 300 - 350 °C and keep warm for 2 h, then heat up to 700 - 800 °C and keep warm for 3 h.

[0009] Preferably, the molar ratio of tin (II) chloride pentahydrate, ammonium fluoride, and urea in step s2 is 1:(1 - 2):2; the dosage of cerium (III) chloride heptahydrate is 8 - 10 wt% of tin (II) chloride pentahydrate; the dosage ratio of porous biochar, two-dimensional titanium carbide nanosheets, and tin (II) chloride pentahydrate is 1:(0.10 - 0.15):(0.4 - 0.6).

[0010] The preparation steps of the electrode material include: Step 1: Place sodium alginate and acrylamide in deionized water, heat in a water bath to 50 °C and keep constant temperature, add an initiator and stir for 30 min, then add an accelerator and continue to react for 3 h to obtain a polymer solution; Step 2: Take the active material and a conductive agent, mix them by ball milling, then add the polymer solution, calcium chloride, a crosslinking agent, and an initiator prepared in step 1 and mix to obtain an active slurry. Coat it on the surface of a copper foil, react at 70 °C for 30 min, then heat up to 80 °C, dry for 12 h, and then perform heat treatment, treat at 800 - 900 °C for 1 - 2 h to obtain the electrode material.

[0011] Preferably, the dosage of the initiator in step 1 is 0.1 - 0.3 wt% of acrylamide; the dosage of the accelerator is 0.05 wt% of acrylamide; the mass ratio of sodium alginate to acrylamide is 1:(3 - 5); Preferably, the mass ratio of the active material to the conductive agent in step 2 is (8 - 10):1; the dosage of the polymer solution is 20 - 25 wt% of the active material, and the crosslinking agent accounts for 0.25 wt% of the polymer solution; Preferably, the active material areal loading of the electrode material is 1.0 - 1.2 mg / cm 2 .

[0012] Compared with the prior art, the beneficial effects of the present invention are: 1. The present invention provides a method for preparing a lithium-ion battery electrode material, in which the active material is selected from agricultural waste rice husks and bamboo raw materials for treatment. The rice husks and bamboo are infiltrated with an activator and pyrolytically carbonized to obtain a biochar with a porous structure. Then, tin oxide and Ce compounds are introduced and blended with two-dimensional titanium carbide nanosheets to relieve the volume expansion generated during the Si cycle and provide buffering, effectively improving the conductivity of the material, increasing the ion transport rate. At the same time, the vacancies generated during the hydrothermal reaction of tin (IV) chloride pentahydrate, cerium (III) chloride heptahydrate, ammonium fluoride and urea also provide more lithium storage sites for the electrode material; 2. The binder is a crosslinked polymer. Sodium alginate is grafted with acrylamide and then crosslinked to obtain a polymer binder. After mixing with the active material and the conductive agent, secondary crosslinking is carried out to improve the density of the molecular network. The slurry is coated on a copper foil to improve the binding force between the binder, the active material, the conductive agent and the copper foil. Then, heat treatment is carried out to convert it into a conductive carbon material, which is beneficial to lithium-ion transport and improves conductivity. In addition, heat treatment generates a Cu 3 Si buffer phase, which cooperates with the above conductive carbon material to relieve the volume expansion of Si, improve the cycle stability of the electrode material and increase the cycle life. Specific embodiments

[0013] Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present invention.

[0014] In the experiment, the activator is zinc chloride; the initiator is ammonium persulfate; the accelerator is N,N,N',N'-tetramethylethylenediamine; the crosslinking agent is N,N'-methylenebisacrylamide; the conductive agent is acetylene black; Preparation of bamboo powder and rice husk powder: Bamboo and rice husks are respectively fed into a pulverizer for pulverization and passed through a 60-mesh sieve to obtain bamboo powder and rice husk powder respectively.

[0015] Example 1: This example provides a method for preparing a lithium-ion battery electrode material and the assembly of a lithium-ion battery. The steps are as follows: Step 1: Take 3 g of bamboo powder and 2 g of rice husk powder, immerse them in 50 mL of deionized water, add 10 g of zinc chloride and mix. After soaking for 12 h, filter and dry, then transfer them to a muffle furnace for pyrolytic carbonization. Heat up to 300 °C and hold for 2 h, then heat up to 700 °C and hold for 3 h. After carbonization, transfer them to a water bath, add 25 mL of 1 M hydrochloric acid, heat up to 100 °C and stir for 2 h. Filter, wash and dry at 90 °C for 14 h to obtain porous biochar; Step 2: Sequentially add 1.05 g of tin chloride pentahydrate, 0.1 g of cerium trichloride heptahydrate, 0.22 g of ammonium fluoride, and 0.36 g of urea to 100 mL of deionized water and mix them. Then add 2 g of the porous biochar prepared in Step 1 and 0.2 g of two-dimensional titanium carbide nanosheets, heat to 180 °C and keep warm for 24 h. After washing with deionized water and drying, the active material is obtained.

[0016] Step 3: Place 2.5 g of sodium alginate and 10 g of acrylamide in 100 mL of deionized water, heat in a water bath to 50 °C and keep constant temperature. Add 0.02 g of initiator and stir for 30 min, then add 0.005 g of accelerator and continue to react for 3 h to obtain a polymer solution. Step 4: Take 2 g of the active material prepared in Step 2 and ball-mill and mix it with 0.25 g of conductive agent. Then add 0.5 g of the polymer solution prepared in Step 3, 0.004 g of calcium chloride, 0.001 g of cross-linking agent, and 0.004 g of initiator and mix them to obtain an active slurry. Coat it on the surface of copper foil, react at 70 °C for 30 min, then raise the temperature to 80 °C and dry for 12 h. Place it in a muffle furnace for heat treatment, introduce argon, and treat at 900 °C for 2 h to obtain the electrode material; wherein, the areal loading of the active material is 1.0 mg / cm 2 。

[0017] Assemble a lithium battery: Use the above electrode material as the working electrode, a lithium sheet as the counter electrode, a polypropylene membrane as the separator, and the electrolyte is 1 mol / L LiPF 6 dissolved in a mixed solvent of diethyl carbonate and ethylene carbonate with a volume ratio of 1:1. Assemble a lithium battery in a glove box filled with argon, denoted as Lithium Battery No. 1, and let it stand for 12 h.

[0018] Example 2: This example provides a preparation method of a lithium battery electrode material and the assembly of a lithium battery. The steps are as follows: Step 1: Take 3 g of bamboo powder and 2 g of rice husk powder, immerse them in 50 mL of deionized water, add 10 g of zinc chloride and mix. After soaking for 12 h, filter and dry, then send them into a muffle furnace for pyrolytic carbonization. Raise the temperature to 300 °C and keep warm for 2 h, then raise the temperature to 700 °C and keep warm for 3 h. After carbonization, transfer them to a water bath, add 25 mL of 1 M hydrochloric acid, raise the temperature to 100 °C, stir for 2 h, filter and wash, and dry at 90 °C for 14 h to obtain porous biochar. Step 2: Sequentially add 0.88 g of tin chloride pentahydrate, 0.085 g of cerium trichloride heptahydrate, 0.185 g of ammonium fluoride, and 0.30 g of urea to 100 mL of deionized water and mix them. Then add 2 g of the porous biochar prepared in Step 1 and 0.25 g of two-dimensional titanium carbide nanosheets, heat to 180 °C and keep warm for 24 h. After washing with deionized water and drying, the active material is obtained.

[0019] Step 3: Place 2.5 g of sodium alginate and 10 g of acrylamide in 100 mL of deionized water, heat in a water bath to 50 °C and keep constant temperature, add 0.02 g of initiator and stir for 30 min, then add 0.005 g of accelerator and continue to react for 3 h to obtain a polymer solution; Step 4: Take 2 g of the active material prepared in Step 2, ball-mill and mix it with 0.25 g of conductive agent, then add 0.5 g of the polymer solution prepared in Step 3, 0.004 g of calcium chloride, 0.001 g of cross-linking agent and 0.004 g of initiator and mix them to obtain an active slurry. Coat it on the surface of copper foil, react at 70 °C for 30 min, then raise the temperature to 80 °C and dry for 12 h, place it in a muffle furnace for heat treatment, introduce argon gas, and treat it at 900 °C for 2 h to obtain the electrode material; among them, the surface loading of the active material is 1.0 mg / cm 2 .

[0020] Assemble a lithium battery: Use the above electrode material as the working electrode, a lithium sheet as the counter electrode, a polypropylene film as the separator, and the electrolyte is 1 mol / L LiPF 6 dissolved in a mixed solvent of diethyl carbonate and ethylene carbonate with a volume ratio of 1:1. Assemble a lithium battery in a glove box filled with argon gas, denoted as Lithium Battery No. 2, and let it stand for 12 h.

[0021] Example 3: This example provides a preparation method of a lithium battery electrode material and the assembly of a lithium battery. The steps are as follows: Step 1: Take 3 g of bamboo powder and 2 g of rice husk powder, immerse them in 50 mL of deionized water, add 10 g of zinc chloride and mix. After soaking for 12 h, filter and dry, then send them into a muffle furnace for pyrolysis carbonization. Raise the temperature to 300 °C and keep it for 2 h, then raise the temperature to 700 °C and keep it for 3 h. After carbonization, transfer it to a water bath, add 25 mL of 1 M hydrochloric acid, raise the temperature to 80 °C, stir for 2 h, filter and wash, and dry at 90 °C for 14 h to obtain porous biochar; Step 2: Add 1.05 g of tin (II) chloride pentahydrate, 0.1 g of cerium (III) chloride heptahydrate, 0.22 g of ammonium fluoride and 0.36 g of urea to 100 mL of deionized water in sequence, then add 2 g of the porous biochar prepared in Step 1 and 0.2 g of two-dimensional titanium carbide nanosheets, heat to 180 °C and keep it for 24 h, wash with deionized water and dry to obtain the active material.

[0022] Step 3: Place 2.5 g of sodium alginate and 10 g of acrylamide in 100 mL of deionized water, heat in a water bath to 50 °C and keep constant temperature, add 0.02 g of initiator and stir for 30 min, then add 0.005 g of accelerator and continue to react for 3 h to obtain a polymer solution; Step 4: Take 2 g of the active material prepared in Step 2 and ball-mill and mix it with 0.22 g of conductive agent. Then add 0.4 g of the polymer solution prepared in Step 3, 0.004 g of calcium chloride, 0.001 g of cross-linking agent and 0.004 g of initiator and mix them to obtain an active slurry. Coat it on the surface of copper foil, react at 70 °C for 30 min, then raise the temperature to 80 °C and dry for 12 h. Place it in a muffle furnace for heat treatment, introduce argon gas, and treat it at 900 °C for 2 h to obtain the electrode material; among them, the areal loading of the active material is 1.0 mg / cm 2 .

[0023] Assemble a lithium battery: Use the above electrode material as the working electrode, a lithium sheet as the counter electrode, a polypropylene film as the separator, and the electrolyte is 1 mol / L LiPF 6 dissolved in a mixed solvent of diethyl carbonate and ethylene carbonate with a volume ratio of 1:1. Assemble a lithium battery in a glove box filled with argon gas, denoted as Lithium Battery No. 3, and let it stand for 12 h.

[0024] Example 4: This example provides a preparation method of a lithium battery electrode material and the assembly of a lithium battery. The steps are as follows: Step 1: Take 3 g of bamboo powder and 2 g of rice husk powder, immerse them in 50 mL of deionized water, add 10 g of zinc chloride and mix. After soaking for 12 h, filter and dry, then send them into a muffle furnace for pyrolytic carbonization. Raise the temperature to 350 °C and keep it warm for 2 h, then raise the temperature to 800 °C and keep it warm for 3 h. After carbonization, transfer it to a water bath, add 25 mL of 1 M hydrochloric acid, raise the temperature to 100 °C, stir for 2 h, filter and wash, and then dry at 90 °C for 14 h to obtain porous biochar; Step 2: Sequentially add 1.05 g of tin (II) chloride pentahydrate, 0.09 g of cerium (III) chloride heptahydrate, 0.22 g of ammonium fluoride and 0.36 g of urea to 100 mL of deionized water and mix. Then add 2 g of the porous biochar prepared in Step 1 and 0.2 g of two-dimensional titanium carbide nanosheets, heat to 180 °C and keep it warm for 24 h, wash with deionized water and dry to obtain the active material.

[0025] Step 3: Place 2.5 g of sodium alginate and 10 g of acrylamide in 100 mL of deionized water and heat it in a water bath to 50 °C and keep it constant. Add 0.02 g of initiator and stir for 30 min, then add 0.005 g of accelerator and continue to react for 3 h to obtain a polymer solution; Step 4: Take 2 g of the active material prepared in Step 2 and mix it with 0.22 g of conductive agent by ball milling. Then add 0.5 g of the polymer solution prepared in Step 3, 0.004 g of calcium chloride, 0.001 g of crosslinking agent and 0.004 g of initiator and mix them to obtain an active slurry. Coat the slurry on the surface of copper foil, react at 70 °C for 30 min, then raise the temperature to 80 °C and dry for 12 h. Place it in a muffle furnace for heat treatment, introduce argon gas, and treat it at 900 °C for 1 h to obtain the electrode material; wherein, the areal loading of the active material is 1.0 mg / cm 2 。

[0026] Assemble a lithium battery: Use the above electrode material as the working electrode, a lithium sheet as the counter electrode, a polypropylene membrane as the separator, and the electrolyte is 1 mol / L LiPF 6 dissolved in a mixed solvent of diethyl carbonate and ethylene carbonate with a volume ratio of 1:1. Assemble the lithium battery in a glove box filled with argon gas, denoted as Lithium Battery No. 4, and let it stand for 12 h.

[0027] Example 5: This example provides a method for preparing a lithium battery electrode material and assembling a lithium battery. The steps are as follows: Step 1: Take 3 g of bamboo powder and 2 g of rice husk powder, immerse them in 50 mL of deionized water, add 10 g of zinc chloride and mix. After soaking for 12 h, filter and dry, then send them into a muffle furnace for pyrolytic carbonization. Raise the temperature to 300 °C and hold for 2 h, then raise the temperature to 700 °C and hold for 3 h. After carbonization, transfer it to a water bath, add 25 mL of 1 M hydrochloric acid, raise the temperature to 100 °C, stir for 2 h, filter and wash, and then dry at 90 °C for 14 h to obtain porous biochar; Step 2: Sequentially add 1.15 g of tin (II) chloride pentahydrate, 0.11 g of cerium (III) chloride heptahydrate, 0.12 g of ammonium fluoride and 0.36 g of urea to 100 mL of deionized water and mix. Then add 2 g of the porous biochar prepared in Step 1 and 0.2 g of two-dimensional titanium carbide nanosheets, heat to 180 °C and hold for 24 h, wash with deionized water and dry to obtain the active material.

[0028] Step 3: Place 2.5 g of sodium alginate and 10 g of acrylamide in 100 mL of deionized water, heat in a water bath to 50 °C and keep it at a constant temperature, add 0.02 g of initiator and stir for 30 min, then add 0.005 g of accelerator and continue to react for 3 h to obtain a polymer solution; Step 4: Take 2 g of the active material prepared in Step 2 and mix it with 0.25 g of the conductive agent by ball milling. Then add 0.5 g of the polymer solution prepared in Step 3, 0.004 g of calcium chloride, 0.001 g of the crosslinking agent, and 0.004 g of the initiator and mix them to obtain the active slurry. Coat the active slurry on the surface of the copper foil, react at 70 °C for 30 min, then raise the temperature to 80 °C and dry for 12 h. Place it in a muffle furnace for heat treatment, introduce argon, and treat it at 900 °C for 1 h to obtain the electrode material; among them, the areal loading of the active material is 1.0 mg / cm 2 .

[0029] Assemble a lithium battery: Use the above electrode material as the working electrode, a lithium sheet as the counter electrode, a polypropylene membrane as the separator, and the electrolyte is 1 mol / L LiPF 6 dissolved in a mixed solvent of diethyl carbonate and ethylene carbonate with a volume ratio of 1:1. Assemble the lithium battery in a glove box filled with argon, denoted as Lithium Battery No. 5, and let it stand for 12 h.

[0030] Comparative Example 1: This example is a control experiment of Example 1 without adding cerium trichloride heptahydrate. The steps are as follows: Step 1: Take 3 g of bamboo powder and 2 g of rice husk powder, immerse them in 50 mL of deionized water, add 10 g of zinc chloride and mix. After soaking for 12 h, filter and dry, then send them into a muffle furnace for pyrolytic carbonization. Raise the temperature to 300 °C and hold for 2 h, then raise the temperature to 700 °C and hold for 3 h. After carbonization, add 25 mL of 1 M hydrochloric acid, raise the temperature to 80 - 100 °C, stir for 2 h, filter and wash, and then dry at 90 °C for 14 h to obtain the porous biochar; Step 2: Add 1.05 g of stannous chloride pentahydrate, 0.22 g of ammonium fluoride, and 0.36 g of urea to 100 mL of deionized water in sequence, then add 2 g of the porous biochar prepared in Step S1 and 0.2 g of two-dimensional titanium carbide nanosheets, heat to 180 °C and hold for 24 h, wash with deionized water and dry to obtain the active material.

[0031] Step 3: Place 2.5 g of sodium alginate and 10 g of acrylamide in 100 mL of deionized water, heat in a water bath to 50 °C and keep it constant temperature, add 0.02 g of the initiator and stir for 30 min, then add 0.005 g of the accelerator and continue to react for 3 h to obtain the polymer solution; Step 4: Take 2 g of the active material prepared in Step 2 and mix it with 0.22 g of the conductive agent by ball milling. Then add 0.5 g of the polymer solution prepared in Step 1, 0.004 g of calcium chloride, 0.001 g of the crosslinking agent, and 0.004 g of the initiator and mix them to obtain the active slurry. Coat the active slurry on the surface of the copper foil, react at 70 °C for 30 min, then raise the temperature to 80 °C and dry for 12 h. Place it in a muffle furnace for heat treatment, introduce argon, and treat it at 900 °C for 2 h to obtain the electrode material; among them, the areal loading of the active material is 1.0 mg / cm 2 .

[0032] Assembly of lithium battery: Using the above electrode material as the working electrode, a lithium sheet as the counter electrode, a polypropylene membrane as the separator, and the electrolyte is 1 mol / L LiPF 6 dissolved in a mixed solvent of diethyl carbonate and ethylene carbonate with a volume ratio of 1:1. Assemble the lithium battery in a glove box filled with argon gas, denoted as lithium battery No. 6, and let it stand for 12 h.

[0033] Comparative Example 2: This example is a control experiment of Example 1. The binder is adjusted to polyacrylic acid with an effective solid content of 20% purchased from Huaxiang Kejie. The specific steps are as follows: Step 1: Take 3 g of bamboo powder and 2 g of rice husk powder, immerse them in 50 mL of deionized water, add 10 g of zinc chloride and mix. After soaking for 12 h, filter and dry, then send them into a muffle furnace for pyrolytic carbonization. Heat up to 300 °C and hold for 2 h, then heat up to 700 °C and hold for 3 h. After carbonization, add 25 mL of 1 M hydrochloric acid, heat up to 100 °C, stir for 2 h, filter and wash, and then dry at 90 °C for 14 h to obtain porous biochar; Step 2: Add 1.05 g of tin (II) chloride pentahydrate, 0.1 g of cerium (III) chloride heptahydrate, 0.22 g of ammonium fluoride and 0.36 g of urea to 100 mL of deionized water in sequence, then add 2 g of the porous biochar prepared in step s1 and 0.2 g of two-dimensional titanium carbide nanosheets, heat up to 180 °C and hold for 24 h, wash with deionized water and then dry to obtain the active material.

[0034] Step 3: Take 2 g of the active material prepared in step 2, ball-mill and mix it with 0.22 g of conductive agent, then add 0.5 g of polyacrylic acid to obtain an active slurry. Coat it on the surface of copper foil, react at 70 °C for 30 min, then heat up to 80 °C and dry for 12 h, and place it in a muffle furnace for heat treatment, introduce argon gas, and treat it at 900 °C for 2 h to obtain the electrode material; among them, the areal loading of the active material is 1.0 mg / cm 2 。

[0035] Assembly of lithium battery: Using the above electrode material as the working electrode, a lithium sheet as the counter electrode, a polypropylene membrane as the separator, and the electrolyte is 1 mol / L LiPF 6 dissolved in a mixed solvent of diethyl carbonate and ethylene carbonate with a volume ratio of 1:1. Assemble the lithium battery in a glove box filled with argon gas, denoted as lithium battery No. 7, and let it stand for 12 h.

[0036] Comparative Example 3: This example is a control experiment of Example 1. In step 4, no heat treatment is carried out. The steps are as follows: Step 1: Take 3 g of bamboo powder and 2 g of rice husk powder, immerse them in 50 mL of deionized water, add 10 g of zinc chloride and mix. After soaking for 12 h, filter and dry, then send them into a muffle furnace for pyrolytic carbonization. Heat up to 300 °C and hold for 2 h, then heat up to 700 °C and hold for 3 h. After carbonization, transfer them to a water bath, add 25 mL of 1 M hydrochloric acid, heat up to 100 °C, stir for 2 h, filter and wash, and then dry at 90 °C for 14 h to obtain porous biochar; Step 2: Sequentially add 1.05 g of stannous chloride pentahydrate, 0.1 g of cerium trichloride heptahydrate, 0.22 g of ammonium fluoride, and 0.36 g of urea to 100 mL of deionized water and mix. Then add 2 g of the porous biochar prepared in Step 1 and 0.2 g of two-dimensional titanium carbide nanosheets, heat to 180 °C and hold for 24 h, wash with deionized water and dry to obtain the active material.

[0037] Step 3: Place 2.5 g of sodium alginate and 10 g of acrylamide in 100 mL of deionized water, heat in a water bath to 50 °C and keep it constant temperature, add 0.02 g of initiator and stir for 30 min, then add 0.005 g of accelerator and continue to react for 3 h to obtain a polymer solution; Step 4: Take 2 g of the active material prepared in Step 2, ball-mill and mix it with 0.25 g of conductive agent, then add 0.5 g of the polymer solution prepared in Step 3, 0.004 g of calcium chloride, 0.001 g of crosslinking agent, and 0.004 g of initiator and mix to obtain an active slurry. Coat it on the surface of copper foil, react at 70 °C for 30 min, then heat up to 80 °C and dry for 12 h to obtain the electrode material; among them, the areal loading of the active material is 1.0 mg / cm 2 。

[0038] Assemble a lithium battery: Use the above electrode material as the working electrode, a lithium sheet as the counter electrode, a polypropylene membrane as the separator, and the electrolyte is 1 mol / L LiPF 6 dissolved in a mixed solvent of diethyl carbonate and ethylene carbonate with a volume ratio of 1:1. Assemble a lithium battery in a glove box filled with argon gas, denoted as Lithium Battery No. 8, and let it stand for 12 h.

[0039] Detection test Use the battery test system CT2001A battery tester of Wuhan Blue Electric Co., Ltd. to conduct 200-cycle tests, set the charge-discharge current density to 0.2 A / g -1 , the voltage range is from 0.01 - 3 V, and record the experimental data as shown in the following table:

[0040] Conclusion: From the above data, it can be seen that the comprehensive electrochemical performance of Example 1 is superior to the other four groups of examples, and the formulation effect is good; in Comparative Example 1, Ce element is not introduced, which has a certain impact on the cycle performance. It can be seen that the addition of a small amount of Ce element can effectively improve the cycle performance of lithium batteries; in Comparative Example 2, the binder is replaced with common polyacrylic acid on the market, and the electrochemical performance of the lithium battery drops significantly; in Comparative Example 3, no heat treatment is carried out, and the electrochemical performance of the lithium battery drops.

[0041] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a lithium battery electrode material, characterized in that: The electrode material is obtained by combining an electrode sheet and an active slurry coated on the surface of the electrode sheet; the active slurry includes an active material; the preparation steps of the active material are as follows: Step s1: crush bamboo and rice husk to obtain bamboo powder and rice husk powder, immerse them in deionized water, add an activator, soak for 12 hours, filter and dry, then perform pyrolysis carbonization, add hydrochloric acid after carbonization, heat to 80-100°C, stir for 2 hours, filter and wash, and then dry at 90°C for 14 hours to obtain porous biochar; Step s2: Add tin chloride pentahydrate, cerium chloride heptahydrate, ammonium fluoride and urea to deionized water in sequence, and then add the porous biocarbon and two-dimensional nano-titanium carbide prepared in step s1, heat to 180-200°C and keep warm for 24 hours, wash with deionized water and dry to obtain an active material.

2. The method for preparing a lithium battery electrode material according to claim 1, characterized in that: The process parameters of pyrolysis carbonization in step s1 are: heating to 300-350°C and keeping it for 2 hours, and then heating to 700-800°C and keeping it for 3 hours.

3. The method for preparing a lithium battery electrode material according to claim 1, characterized in that: In step s2, the molar ratio of tin chloride pentahydrate, ammonium fluoride and urea is 1: (1-2): 2; the amount of cerium trichloride heptahydrate is 8-10wt% of the tin chloride pentahydrate; the amount ratio of porous biocarbon, two-dimensional nano-titanium carbide and tin chloride pentahydrate is 1: (0.10-0.15): (0.4-0.6).

4. The method for preparing a lithium battery electrode material according to claim 1, characterized in that: The preparation steps of the electrode material include: Step 1: Place sodium alginate and acrylamide in deionized water and heat to 50°C in a water bath, add an initiator and stir for 30 minutes, then add an accelerator and continue the reaction for 3 hours to obtain a polymer solution; Step 2: After ball-milling the active material and the conductive agent, add the polymer solution prepared in step 1, calcium chloride, a cross-linking agent and an initiator to obtain an active slurry, apply it on the surface of the copper foil, react at 70°C for 30 minutes, then heat it to 80°C, dry it for 12 hours, and then heat treat it at 800-900°C for 1-2 hours to obtain the electrode material.

5. The method for preparing a lithium battery electrode material according to claim 5, characterized in that: In step 1, the amount of the initiator used is 0.1-0.3wt% of acrylamide; the amount of the accelerator used is 0.05wt% of acrylamide; and the mass ratio of sodium alginate to acrylamide is 1:(3-5).

6. The method for preparing a lithium battery electrode material according to claim 5, characterized in that: In step 2, the mass ratio of active material to conductive agent is (8-10):1; the amount of polymer solution used is 20-25wt% of active material, and the cross-linking agent accounts for 0.005wt% of the polymer solution.

7. The method for preparing a lithium battery electrode material according to claim 5, characterized in that: The active material surface loading of the electrode material is 1.0-1.2 mg / cm 2 .

8. A lithium battery electrode material, characterized in that: The method is prepared according to claim 1.

9. A use of the lithium battery electrode material as claimed in claim 8 in a lithium battery, characterized in that: Including electrode materials, diaphragms, counter electrodes, electrolytes and battery casings.

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