Copper-doped silicon oxide coated carbon lithium battery negative electrode material and preparation method thereof

Abstract

The invention provides a copper-doped silicon oxide coated carbon lithium battery negative electrode material and a preparation method thereof, the microstructure of the copper-doped silicon oxide coated carbon lithium battery negative electrode material is a layered structure, the outer layer is a copper-doped silicon oxide, and the inner layer is carbon. The synthesis method of the material is a solvothermal method, and the method is simple and suitable for large-scale production. According to the copper-doped silicon oxide coated carbon lithium battery negative electrode material synthesized according to the formula disclosed by the invention, a nano-level coating is formed, the coating effect is uniform, the coating amount is controllable, the volume expansion effect of the material is greatly improved, the conductivity of the copper-doped material is improved, and the cycling stability of the battery is greatly improved.

Description

Technical Field

[0001] The invention relates to the field of lithium battery negative electrode materials, in particular to a lithium battery negative electrode material of copper-doped silicon oxide coated carbon and a preparation method thereof. Background Art

[0002] As a negative electrode material for lithium-ion batteries, silicon oxide has a theoretical capacity of up to 2600mAh / g, but it also has disadvantages such as poor conductivity and volume expansion during charging and discharging. The use of highly conductive carbon materials, conductive metal elements, conductive polymers, etc. to coat and / or dope silicon oxide can significantly improve the conductivity of silicon oxide negative electrode materials and the cycle stability of batteries. However, in practical applications, coated and / or doped silicon oxide negative electrode materials usually encounter problems such as crystal growth and uneven distribution during the calcination process. Summary of the invention

[0003] In order to solve the above problems, the present invention provides a copper-doped silicon oxide-coated carbon lithium battery negative electrode material, so that the coating or modified substance is evenly distributed on the surface of carbon (at least one of graphite, hard carbon, and soft carbon).

[0004] A copper-doped silicon oxide-coated carbon lithium battery negative electrode material, wherein the molar ratio of silicon element to copper element is 2.5:1-12:1, and the content of carbon is 50%-99% of the total mass of the copper-doped silicon oxide-coated carbon lithium battery negative electrode material; The microstructure of the copper-doped silicon oxide coated carbon lithium battery negative electrode material is a layered structure, with the outer layer being copper-doped silicon oxide and the inner layer being carbon.

[0005] The copper-doped silicon oxide is in the form of particles or fiber mesh, and the particle size is between 10-100 nm.

[0006] A method for preparing a copper-doped silicon oxide-coated carbon lithium battery negative electrode material comprises the following steps: S1: Take calculated amounts of ethanol, ethylene glycol, carbon, water, organic acid, organosilicon, copper salt, and catalyst in turn, add them into a beaker, stir and mix them evenly, and obtain a mixed solution; S2: introducing the mixed solution into a reactor, carrying out a homogeneous reaction at a certain temperature, and then cooling to obtain a suspension; S3: drying the suspension to obtain a precursor, and sintering the precursor at a high temperature under an inert atmosphere to obtain a copper-doped silicon oxide-coated carbon lithium battery negative electrode material.

[0007] Preferably, the mass percentage of ethylene glycol to ethanol in step S1 is 1:99-85:15.

[0008] Preferably, the carbon material in step S1 is at least one of graphite, hard carbon, and soft carbon.

[0009] Preferably, the catalyst in step S1 is one of an acidic catalyst or a basic catalyst.

[0010] Preferably, the acidic catalyst in step S1 is selected from at least one of citric acid, polyacrylic acid, phosphoric acid, pyrophosphoric acid, and phytic acid.

[0011] Preferably, phosphoric acid, pyrophosphoric acid, and phytic acid in the acidic catalyst are phosphorus-containing catalysts, and the molar ratio of the copper element to the phosphorus element in the phosphorus-containing catalyst is 0.08 - 2.1.

[0012] Preferably, the basic catalyst is selected from one or more of aniline, dicyandiamide, and polyacrylonitrile.

[0013] Preferably, the molar ratio of the copper element to the nitrogen element in the basic catalyst is 0.06 - 1.1.

[0014] Preferably, the organosilicon is selected from one or more of methyl silicate, ethyl silicate, propyl silicate, and mixed silicate esters of silicic acid (the hydrocarbon groups in the silicic acid esters have different carbon numbers and structures).

[0015] Preferably, the copper salt is selected from copper organic carboxylate or copper acetylacetonate.

[0016] Preferably, the molar ratio value range of water to silicon element is 1 - 8.

[0017] Preferably, the molar ratio value range of ethylene glycol to silicon element in step S1 is 15 - 0.

[0018] Preferably, the organic acid in step S1 is selected from citric acid or polyacrylic acid.

[0019] Preferably, the reaction temperature in step S2 is selected from 160°C - 200°C.

[0020] Preferably, the drying method in step S3 is selected from one of suction filtration drying and spray drying.

[0021] Preferably, the inert atmosphere in step S3 is selected from one of a nitrogen atmosphere and an argon atmosphere.

[0022] Preferably, the high sintering temperature in step S3 is selected from 500°C - 1100°C.

[0023] The technical solution provided by the present invention can achieve the following beneficial effects: In the preparation method of the lithium battery anode material with copper-doped silicon oxide-coated carbon provided by the present invention, after the solvothermal reaction, copper is uniformly dispersed in the hydrolyzed silicon oxide, forming copper-doped silicon oxide coated around the carbon. After calcination, metallic copper is generated in the silicon oxide, improving the conductive carbon property of the material. The particle size of the porous silica formed by this method is within 100 nm. The conductivity of the lithium battery anode material with copper-doped silicon oxide-coated carbon is greatly improved, the volume expansion effect of the material is greatly improved, and the cycle stability of the battery is greatly enhanced. Description of the Drawings

[0024] Figure 1 It is the SEM diagram of Example 25.

[0025] Figure 2 It is the cycle diagram of Example 19.

[0026] Figure 3 It is the rate diagram of Example 21.

[0027] Figure 4 It is the charge-discharge curve diagram of Example 22. Embodiments

[0028] The following combines the drawings and examples to further describe in detail the specific embodiments of the present invention. Example 1

[0029] This example provides a preparation method of a lithium battery anode material with copper-doped silicon oxide-coated carbon, including: 1. Weigh 70.00 g of absolute ethanol, add it to a beaker, then add 0.28 g of water and 15.03 g of graphite, stir evenly, transfer the materials into a homogeneous reactor, and then sequentially add 13.01 g of tetraethyl orthosilicate, 1.53 g of copper acetylacetonate, 0.54 g of aniline, and 0.93 g of citric acid into the homogeneous reactor. After stirring, pour it into the inner liner of the reaction kettle and seal the homogeneous reactor; 2. Heat the homogeneous reactor to 180 °C and react for 5 h. After the reaction, cool it to room temperature, filter by suction, wash it once with 20 mL of absolute ethanol to obtain a solid; 3. Put the above solid into a tubular furnace, heat it at a rate of 5 °C / min in a N2 atmosphere, keep it at 700 °C for 5 h, and finally cool it to 300 °C at a rate of 5 °C / min and cool it naturally to obtain a powder sample. Example 2

[0030] This example provides a preparation method of a lithium battery anode material with copper-doped silicon oxide-coated carbon, including: 1. Weigh 70.00 g of ethanol, pour it into a beaker, then add 15.01 g of graphite, stir, and then successively add 13.01 g of tetraethyl orthosilicate, 1.53 g of acetylacetone copper, 0.54 g of aniline, and 0.93 g of citric acid. After stirring, pour the mixture into the inner liner of the autoclave and seal the homogeneous reactor; 2. Heat the homogeneous reactor to 180 °C and react for 5 h. After the reaction, soak the inner liner of the autoclave in water for 20 min for rapid cooling, perform suction filtration, and wash it with 20 mL of anhydrous ethanol to obtain a solid; 3. Put the obtained solid into a tube furnace, heat it at a rate of 5 °C / min under a N2 atmosphere until it reaches 700 °C, hold for 5 h, and finally cool it to 300 °C at a rate of 5 °C / min and then let it cool naturally to obtain a powder sample; 4. Add the powder sample, SP, and PVDF to the ball milling tank at a mass ratio of 92.6:4.4:3, ball mill at 180 r / min for 20 min, coat to a thickness of 120 μm, dry and slice, and bake in a vacuum at 90 °C for 12 h. The prepared electrode sheet is used as the positive electrode of a half-cell, the lithium sheet is used as the negative electrode, and 1 mol / L LiPF6 in EC / DEC / DMC (volume ratio 1:1:1) is used as the electrolyte to make a CR2032 type button cell.

[0031] Test the button cell. Charge and discharge the cell at a current density of 33 mA / g. The first reversible capacity of the cell is 370 mAh / g, and the first capacity is greater than the reversible capacity of graphite, which is 350 mAh / g. Example 3

[0032] This example provides a method for preparing a lithium battery anode material of copper-doped silicon oxide-coated carbon, which includes: 1. Weigh 70.00 g of anhydrous ethanol, pour it into a beaker, then add 0.28 g of water, add 15.03 g of graphite, stir, and then successively add 13.01 g of tetraethyl orthosilicate, 1.53 g of acetylacetone copper, 0.54 g of aniline, and 0.93 g of citric acid. After stirring, pour the mixture into the inner liner of the autoclave and seal the homogeneous reactor; 2. Heat the homogeneous reactor to 180 °C and react for 5 h. After the reaction, soak it in water for 20 min for rapid cooling, perform suction filtration, and wash it with 20 mL of anhydrous ethanol to obtain a solid; 3. Put the obtained solid into a tube furnace, heat it at a rate of 5 °C / min under a N2 atmosphere until it reaches 700 °C, hold for 5 h, and finally cool it to 300 °C at a rate of 5 °C / min and then let it cool naturally to obtain a powder sample. Example 4

[0033] This example provides a method for preparing a lithium battery anode material of copper-doped silicon oxide-coated carbon, which includes: 1. Weigh 80.00 g of absolute ethanol, pour it into a beaker, then add 2.25 g of water, add 15.01 g of graphite, stir, and then successively add 13.01 g of tetraethyl orthosilicate, 1.53 g of copper acetylacetonate, 0.54 g of aniline, and 0.93 g of citric acid. After stirring, pour it into the inner liner of the reaction kettle and seal the homogeneous reactor; 2. Heat the homogeneous reactor to 180 °C and react for 5 h. After the reaction, soak it in water for 20 min for rapid cooling, filter by suction, and wash the obtained solid with 20 mL of absolute ethanol; 3. Put the above-obtained solid into a tube furnace, heat it up at a rate of 5 °C / min under a N2 atmosphere, keep it at 700 °C for 5 h, and finally cool it down to 300 °C at a rate of 5 °C / min and let it cool naturally to obtain a powder sample; 4. Add the powder sample, SP, and PVDF to the ball milling tank at a mass ratio of 92.6:4.4:3, ball mill for 20 min at 180 r / min of the ball mill, coat it to a thickness of 120 μm, dry and slice it, and bake it in a vacuum at 90 °C for 12 h. The prepared electrode sheet is the positive electrode of the half-cell, the lithium sheet is the negative electrode, and 1 mol / L LiPF6 in EC / DEC / DMC (volume ratio 1:1:1) is used as the electrolyte to make a CR2032 type button cell.

[0034] Test the button cell. Charge and discharge the cell at a current density of 33 mA / g. The first reversible capacity of the cell is 369 mAh / g. Example 5

[0035] This example provides a method for preparing a lithium battery anode material doped with copper and coated with silicon oxide on carbon, including: 1. Weigh 80.00 g of absolute ethanol, pour it into a beaker, then add 2.25 g of water, add 15.00 g of graphite, stir, and then successively add 13.01 g of tetraethyl orthosilicate, 6.53 g of copper acetylacetonate, 2.32 g of aniline, and 0.93 g of citric acid. After stirring, pour it into the inner liner of the reaction kettle and seal the homogeneous reaction kettle; 2. Heat the homogeneous reactor to 180 °C and react for 5 h. After the reaction, soak it in water for 20 min for rapid cooling, filter by suction, and wash the obtained solid with 20 mL of absolute ethanol; 3. Put the above-obtained solid into a tube furnace, heat it up at a rate of 5 °C / min under a N2 atmosphere, keep it at 700 °C for 5 h, and finally cool it down to 300 °C at a rate of 5 °C / min and let it cool naturally to obtain a powder sample. Example 6

[0036] This example provides a method for preparing a lithium battery anode material doped with copper and coated with silicon oxide on carbon, including: 1. Weigh 95.0 g of absolute ethanol, pour it into a beaker, then add 5.0 g of water, add 15.01 g of graphite, stir, and then successively add 13.00 g of tetraethyl orthosilicate, 1.53 g of acetylacetone copper, 0.54 g of aniline, 0.93 g of citric acid, and 0.92 g of phytic acid. After stirring, pour it into the inner liner of the reaction kettle and seal the homogeneous reaction kettle; 2. Heat the homogeneous reactor to 180 °C and react for 5 h. After the reaction, soak it in water for 20 min for rapid cooling, filter by suction, and wash the obtained solid with 20 mL of absolute ethanol; 3. Put the solid obtained above into a tubular furnace, heat it up at a rate of 5 °C / min under a N2 atmosphere, keep it at 700 °C for 5 h, and finally cool it down to 300 °C at a rate of 5 °C / min and cool it naturally to obtain a powder sample. Example 7

[0037] This example provides a preparation method for a lithium battery anode material with copper-doped silicon oxide-coated carbon, including: 1. Weigh 100.00 g of absolute ethanol, pour it into a beaker, then add 1.12 g of water, add 15.00 g of graphite, stir, and then successively add 13.00 g of tetraethyl orthosilicate, 1.53 g of acetylacetone copper, and 8.93 g of phytic acid. After stirring, pour it into the inner liner of the reaction kettle and seal the homogeneous reaction kettle; 2. Heat the homogeneous reactor to 180 °C and react for 5 h. After the reaction, soak it in water for 20 min for rapid cooling, filter by suction, and wash the obtained solid with 20 mL of absolute ethanol; 3. Put the solid obtained above into a tubular furnace, heat it up at a rate of 5 °C / min under a N2 atmosphere, keep it at 700 °C for 5 h, and finally cool it down to 300 °C at a rate of 5 °C / min and cool it naturally to obtain a powder sample; 4. Add the sample powder obtained in C, SP, and PVDF to the ball milling tank at a mass ratio of 92.6:4.4:3, ball mill for 20 min at 180 r / min in a ball mill, coat it with a thickness of 120 μm, dry and slice it, and bake it at 90 °C in vacuum for 12 h. The prepared electrode sheet is the positive electrode of a half-cell, the lithium sheet is the negative electrode, and 1 mol / L LiPF6 in EC / DEC / DMC (volume ratio 1:1:1) is used as the electrolyte to make a CR2032 type button cell.

[0038] Test the button cell. Charge and discharge the battery at a current density of 33 mA / g. The first reversible capacity of the battery is 395 mAh / g, and the energy density of the battery is improved. Example 8

[0039] This example provides a preparation method for a lithium battery anode material with copper-doped silicon oxide-coated carbon, including: 1. Weigh 100.00 g of absolute ethanol, pour it into a beaker, then add 1.12 g of water, add 15.00 g of graphite, stir, and then successively add 13.00 g of tetraethyl orthosilicate, 1.53 g of copper acetylacetonate, and 10.30 g of phytic acid. After stirring, pour it into the inner liner of the reaction kettle and seal the homogeneous reaction kettle; 2. Heat the homogeneous reactor to 180 °C and react for 5 h. After the reaction, soak it in water for 20 min for rapid cooling, perform suction filtration, and wash the obtained solid with 20 mL of absolute ethanol; 3. Put the solid obtained above into a tube furnace, heat it up at a rate of 5 °C / min under a N2 atmosphere, keep it at 700 °C for 5 h, and finally cool it down to 300 °C at a rate of 5 °C / min and cool it naturally to obtain a powder sample. Example 9

[0040] This example provides a method for preparing a lithium battery anode material of copper-doped silicon oxide-coated carbon, including: 1. Weigh 95.00 g of absolute ethanol, pour it into a beaker, then add 5.01 g of water, add 15.00 g of graphite, stir, and then successively add 13.00 g of tetraethyl orthosilicate, 1.53 g of copper acetylacetonate, and 0.92 g of phytic acid. After stirring, pour it into the inner liner of the reaction kettle and seal the homogeneous reaction kettle; 2. Heat the homogeneous reactor to 180 °C and react for 5 h. After the reaction, soak it in water for 20 min for rapid cooling, perform suction filtration, and wash the obtained solid with 20 mL of absolute ethanol; 3. Put the solid obtained above into a tube furnace, heat it up at a rate of 5 °C / min under a N2 atmosphere, keep it at 500 °C for 5 h, and finally cool it down to 300 °C at a rate of 5 °C / min and cool it naturally to obtain a powder sample. Example 10

[0041] The difference between this example and Example 9 is the sintering temperature, which is sintered at 600 °C. Others are the same as Example 9. Example 11

[0042] The difference between this example and Example 9 is the sintering temperature, which is sintered at 700 °C. Others are the same as Example 9. Example 12

[0043] The difference between this example and Example 9 is the sintering temperature, which is sintered at 800 °C. Others are the same as Example 9. By the method of this example, the coin cell is tested and charged and discharged at a current density of 33 mA / g. The first reversible capacity of the battery is 368 mAh / g. Example 13

[0044] The difference between this example and Example 9 is the sintering temperature, which is sintered at 900 °C. Others are the same as Example 9. Example 14

[0045] The difference between the content of this embodiment and that of Embodiment 9 lies in the sintering temperature, which is sintered at 900 °C. The others are the same as those in Embodiment 9. Embodiment 15

[0046] The difference between the content of this embodiment and that of Embodiment 9 lies in the sintering temperature, which is sintered at 1000 °C. The others are the same as those in Embodiment 9. Embodiment 16

[0047] The difference between the content of this embodiment and that of Embodiment 9 lies in the sintering temperature, which is sintered at 1100 °C. The others are the same as those in Embodiment 9. Embodiment 17

[0048] This embodiment provides a preparation method for a negative electrode material of a lithium battery with copper-doped silicon oxide-coated carbon, including: 1. Weigh 30.00 g of absolute ethanol, pour it into a beaker, then add 59.60 g of ethylene glycol, add 15.01 g of graphite, stir, and then successively add 13.01 g of tetraethyl orthosilicate, 1.53 g of copper acetylacetonate, 0.54 g of aniline, and 0.93 g of citric acid. After stirring, pour it into the inner liner of the reaction kettle and seal the homogeneous reaction kettle; 2. Heat the homogeneous reactor to 180 °C and react for 5 h. After the reaction, soak it in water for 20 min for rapid cooling, filter by suction, and wash the obtained solid with 20 mL of absolute ethanol; 3. Put the obtained solid into a tube furnace, heat it up at a rate of 5 °C / min under a N2 atmosphere, keep it at 700 °C for 5 h, and finally cool it down to 300 °C at a rate of 5 °C / min and cool it naturally to obtain a powder sample; 4. Add the powder sample, SP, and PVDF to the ball mill tank at a mass ratio of 92.6:4.4:3, ball mill at 180 r / min for 20 min in the ball mill, coat it to a thickness of 120 μm, dry and slice it, and bake it in a vacuum at 90 °C for 12 h. The prepared electrode sheet is the positive electrode of the half-cell, the lithium sheet is the negative electrode, and 1 mol / L LiPF6 in EC / DEC / DMC (volume ratio 1:1:1) is used as the electrolyte to make a CR2032 type button cell.

[0049] Test the button cell. Charge and discharge the cell at a current density of 33 mA / g. The first reversible capacity of the cell is 370 mAh / g. Embodiment 18

[0050] This embodiment provides a preparation method for a negative electrode material of a lithium battery with copper-doped silicon oxide-coated carbon, including: 1. Weigh 98.00 g of absolute ethanol, pour it into a beaker, then add 1.94 g of ethylene glycol, 15.01 g of graphite, stir, and then successively add 13.01 g of tetraethyl orthosilicate, 1.53 g of acetylacetonato copper, 0.54 g of aniline, and 0.93 g of citric acid. After stirring, pour it into the inner liner of the autoclave and seal the homogeneous reactor; 2. Heat the homogeneous reactor to 180 °C and react for 5 h. After the reaction, soak it in water for 20 min for rapid cooling, perform suction filtration, and wash the obtained solid with 20 mL of absolute ethanol; 3. Put the solid obtained above into a tubular furnace, heat it up at a rate of 5 °C / min under a N2 atmosphere, keep it at 700 °C for 5 h, and finally cool it down to 300 °C at a rate of 5 °C / min and let it cool naturally to obtain a powder sample. Example 19

[0051] This example provides a method for preparing a lithium battery anode material of silicon oxide-coated carbon doped with copper, including: 1. Weigh 30.00 g of absolute ethanol, pour it into a beaker, add 59.60 g of ethylene glycol and 2.25 g of water, stir, add 15.00 g of graphite, stir, and then successively add 13.01 g of tetraethyl orthosilicate, 1.53 g of acetylacetonato copper, 0.54 g of aniline, and 0.93 g of citric acid. After stirring, pour it into the inner liner of the autoclave and seal the homogeneous reactor; 2. Heat the homogeneous reactor to 180 °C and react for 5 h. After the reaction, soak it in water for 20 min for rapid cooling, perform suction filtration to obtain a solid; 3. Put the solid obtained above into a tubular furnace, heat it up at a rate of 5 °C / min under a N2 atmosphere, keep it at 700 °C for 5 h, and finally cool it down to 300 °C at a rate of 5 °C / min and let it cool naturally to obtain a powder sample; 4. Put the powder sample, SP, and PVDF into a ball milling tank in a mass ratio of 92.6:4.4:3, ball mill at 180 r / min for 20 min in a ball mill, coat it to a thickness of 120 μm, dry and slice it, and bake it at 90 °C in vacuum for 12 h. The prepared electrode sheet is used as the positive electrode of a half-cell, the lithium sheet is used as the negative electrode, and 1 mol / L LiPF6 in EC / DEC / DMC (volume ratio 1:1:1) is used as the electrolyte to make a CR2032 type button cell.

[0052] By this method, the capacity of the inorganic substances coated in the material is greatly improved. The button cell is tested, and the battery is charged and discharged at a current density of 33 mA / g. The first reversible capacity of the battery is 398 mAh / g, which has a significant impact on the improvement of the energy density. As Figure 2 shown, when cycled 90 times at a current density of 100 mA / g, the reversible capacity of the material is 364 mAh / g, and the capacity retention rate can reach 91%. Example 20

[0053] This embodiment provides a method for preparing a lithium battery anode material with copper-doped silicon oxide-coated carbon, including: 1. Weigh 15.03 g of absolute ethanol, pour it into a beaker, add 74.98 g of ethylene glycol and 2.25 g of water, stir, add 15.00 g of graphite, stir, and then successively add 13.01 g of tetraethyl orthosilicate, 1.53 g of copper acetylacetonate, 0.54 g of aniline, and 0.93 g of citric acid. After stirring, pour it into the inner liner of the reaction kettle and seal the homogeneous reactor; 2. Heat the homogeneous reactor to 180 °C and react for 5 h. After the reaction, soak it in water for 20 min for rapid cooling, and filter to obtain a solid; 3. Put the obtained solid into a tube furnace, heat it at a rate of 5 °C / min under a N2 atmosphere, keep it at 700 °C for 5 h, and finally cool it to 300 °C at a rate of 5 °C / min and cool it naturally to obtain a powder sample. Example 21

[0054] This embodiment provides a method for preparing a lithium battery anode material with copper-doped silicon oxide-coated carbon, including: 1. Weigh 5.30 g of absolute ethanol, pour it into a beaker, add 79.47 g of ethylene glycol and 1.67 g of water, stir, add 25.00 g of graphite, stir, and then successively add 9.63 g of tetraethyl orthosilicate, 1.14 g of copper acetylacetonate, 0.40 g of aniline, and 1.56 g of citric acid. After stirring, pour it into the inner liner of the reaction kettle and seal the homogeneous reactor; 2. Heat the homogeneous reactor to 180 °C and react for 5 h. After the reaction, soak it in water for 20 min for rapid cooling, and filter to obtain a solid; 3. Put the obtained solid into a tube furnace, heat it at a rate of 5 °C / min under a N2 atmosphere, keep it at 700 °C for 5 h, and finally cool it to 300 °C at a rate of 5 °C / min and cool it naturally to obtain a powder sample.

[0055] 4. Put the powder sample, SP, and PVDF into a ball milling tank in a mass ratio of 92.6:4.4:3, ball mill for 20 min at 180 r / min in a ball mill, coat it with a thickness of 120 μm, dry and slice it, and bake it in a vacuum at 90 °C for 12 h. The prepared electrode sheet is the positive electrode of a half-cell, the lithium sheet is the negative electrode, and 1 mol / L LiPF6 in EC / DEC / DMC (volume ratio 1:1:1) is used as the electrolyte to make a CR2032 type button cell.

[0056] Test the button cell, as Figure 3As shown, the battery was charged and discharged at a current density of 33 mA / g. The first reversible capacity of the battery was 400 mAh / g, which had a significant impact on the improvement of the energy density. It was cycled 20 times at a current density of 100 mA / g, and the reversible capacity of the material was 364 mAh / g, with a capacity retention rate of 91%. It was cycled 20 times at a current density of 200 mA / g, and the reversible capacity of the material was 283 mAh / g, with a capacity retention rate of 70%. It was cycled 20 times at a current density of 300 mA / g, and the reversible capacity of the material was 181 mAh / g, with a capacity retention rate of 45%. It was cycled 20 times at a current density of 100 mA / g, and the reversible capacity of the material returned to 390 mAh / g, with a capacity retention rate of 97.5%. This shows that after the material undergoes rate charge and discharge, the structure of the material does not collapse and the reversibility of the material is good. Example 22

[0057] This example provides a method for preparing a negative electrode material for a lithium battery with copper-doped silicon oxide-coated carbon, including: 1. Weigh 5.30 g of absolute ethanol, pour it into a beaker, then add 79.47 g of ethylene glycol and 0.94 g of water, stir, add 30.00 g of graphite, stir, and then sequentially add 5.47 g of tetraethyl orthosilicate, 0.64 g of copper acetylacetonate, 0.23 g of aniline, and 1.87 g of citric acid. After stirring, pour it into the inner liner of the reaction kettle and seal the homogeneous reactor; 2. Heat the homogeneous reactor to 180 °C and react for 5 h. After the reaction, soak it in water for 20 min to cool it quickly, and filter it to obtain a solid; 3. Put the obtained solid into a tube furnace, heat it at a rate of 5 °C / min in an N2 atmosphere, keep it at 700 °C for 5 h, and finally cool it to 300 °C at a rate of 5 °C / min and cool it naturally to obtain a powder sample.

[0058] 4. Add the powder sample, SP, and PVDF to the ball mill tank in a mass ratio of 92.6:4.4:3, ball mill it at 180 r / min for 20 min in a ball mill, coat it to a thickness of 120 μm, dry it and cut it, and bake it at 90 °C in a vacuum for 12 h. The prepared electrode sheet is the positive electrode of a half-cell, the lithium sheet is the negative electrode, and 1 mol / L LiPF6 in EC / DEC / DMC (volume ratio 1:1:1) is used as the electrolyte to make a CR2032 type button cell.

[0059] The button cell was tested, as Figure 3 shown. The battery was charged and discharged at a current density of 33 mA / g. The first reversible capacity of the battery was 377 mAh / g, and the first charge-discharge efficiency of the battery could reach 79%. The conductivity of the inorganic material was improved. Example 23

[0060] This embodiment provides a method for preparing a lithium battery anode material with copper-doped silicon oxide-coated carbon, which includes: 1. Weigh 30.00 g of absolute ethanol, pour it into a beaker, then add 59.60 g of ethylene glycol, add 15.01 g of graphite, stir, and then successively add 13.01 g of tetraethyl orthosilicate, 1.53 g of copper acetylacetonate, 0.54 g of aniline, and 0.93 g of citric acid. After stirring, pour it into the inner liner of the autoclave and seal the homogeneous reactor; 2. Heat the homogeneous reactor to 180 °C and react for 5 h. After the reaction, soak it in water for 20 min for rapid cooling, perform suction filtration, and wash it with 20 mL of absolute ethanol to obtain a solid; 3. Put the obtained solid into a tube furnace, heat it up at a rate of 5 °C / min under a N2 atmosphere, keep it at 700 °C for 5 h, and finally cool it down to 300 °C at a rate of 5 °C / min and cool it naturally to obtain a powder sample. Example 24

[0061] This embodiment provides a method for preparing a lithium battery anode material with copper-doped silicon oxide-coated carbon, which includes: 1. Weigh 30.00 g of absolute ethanol, pour it into a beaker, then add 59.60 g of ethylene glycol, 2.24 g of water, add 15.01 g of graphite, stir, and then successively add 13.01 g of tetraethyl orthosilicate, 1.17 g of copper acetate, 0.54 g of aniline, and 0.93 g of citric acid. After stirring, pour it into the inner liner of the autoclave and seal the homogeneous reactor; 2. Heat the homogeneous reactor to 180 °C and react for 5 h. After the reaction, soak it in water for 20 min for rapid cooling, perform suction filtration, and wash it with 20 mL of absolute ethanol to obtain a solid; 3. Put the obtained solid into a tube furnace, heat it up at a rate of 5 °C / min under a N2 atmosphere, keep it at 700 °C for 5 h, and finally cool it down to 300 °C at a rate of 5 °C / min and cool it naturally to obtain a powder sample; Example 25

[0062] This embodiment provides a method for preparing a lithium battery anode material with copper-doped silicon oxide-coated carbon, which includes: 1. Weigh 30.00 g of absolute ethanol, pour it into a beaker, then add 59.60 g of ethylene glycol, 2.24 g of water, add 15.01 g of graphite, stir, and then successively add 13.01 g of tetraethyl orthosilicate, 1.05 g of copper citrate, 0.54 g of aniline, and 0.93 g of citric acid. After stirring, pour it into the inner liner of the autoclave and seal the homogeneous reactor; 2. Heat the homogeneous reactor to 180 °C and react for 5 h. After the reaction, soak it in water for 20 min for rapid cooling, perform suction filtration, and wash it with 20 mL of absolute ethanol to obtain a solid; 3. Put the obtained solid into a tube furnace, heat it up at a rate of 5 °C / min under a N2 atmosphere, keep it at 700 °C for 5 h, and finally cool it down to 300 °C at a rate of 5 °C / min and then let it cool naturally to obtain a powder sample.

[0063] 4. Add the powder sample, SP, and PVDF into a ball milling jar at a mass ratio of 92.6:4.4:3, ball mill them for 20 min at 180 r / min in a ball mill, coat them to a thickness of 120 μm, dry and cut them, and bake them in a vacuum at 90 °C for 12 h. The prepared electrode sheet is used as the positive electrode of a half-cell, the lithium sheet is used as the negative electrode, and 1 mol / L LiPF6 in EC / DEC / DMC (volume ratio 1:1:1) is used as the electrolyte to make a CR2032 type button cell.

[0064] For the material synthesized by this method, a layer of nanoscale inorganic material is uniformly coated on the surface of the carbon material. The shape is nanofibrous, and the nanoscale size is about below 100 nm. This nanomaterial can play a good supporting role and overcome the problem of volume expansion of the silicon oxide material. By making a half-cell, with this nanomaterial as the positive electrode and the lithium sheet as the negative electrode, the first reversible capacity of the battery during charge and discharge can reach 396 mAh / g at 33 mA / g, the capacity of the material is exerted, and the energy density of the battery is greatly improved.

[0065] Example 26 This example provides a method for preparing a lithium battery anode material of copper-doped silicon oxide-coated carbon, including: 1. Weigh 30.00 g of absolute ethanol, pour it into a beaker, then add 59.60 g of ethylene glycol, 2.24 g of water, add 15.01 g of graphite, stir, and then successively add 13.01 g of tetraethyl orthosilicate, 3.69 g of copper stearate, 0.54 g of aniline, and 0.93 g of citric acid. After stirring, pour it into the inner liner of the reaction kettle and seal the homogeneous reaction kettle; 2. Heat the homogeneous reactor to 180 °C and react for 5 h. After the reaction, soak it in water for 20 min for rapid cooling, filter it by suction, and wash the obtained solid with 20 mL of absolute ethanol; 3. Put the obtained solid into a tube furnace, heat it up at a rate of 5 °C / min under a N2 atmosphere, keep it at 700 °C for 5 h, and finally cool it down to 300 °C at a rate of 5 °C / min and then let it cool naturally to obtain a powder sample.

[0066] Example 27 This example provides a method for preparing a lithium battery anode material of copper-doped silicon oxide-coated carbon, including: 1. Weigh 5.30 g of absolute ethanol, pour it into a beaker, then add 79.47 g of ethylene glycol and 0.94 g of water, stir, add 30.00 g of graphite, stir, and then successively add 5.47 g of tetraethyl orthosilicate, 0.64 g of acetylacetone copper, 0.23 g of aniline, and 1.87 g of citric acid. After stirring, pour it into the inner liner of the reaction kettle and seal the homogeneous reaction kettle; 2. Heat the homogeneous reactor to 180 °C and react for 5 h. After the reaction, soak it in water for 20 min for rapid cooling, and then spray-dry to obtain a solid; 3. Put the solid obtained above into a tube furnace, heat it up at a rate of 5 °C / min under a N2 atmosphere, keep it at 700 °C for 5 h, and finally cool it down to 300 °C at a rate of 5 °C / min and then cool it naturally to obtain a powder sample; 4. Add the sample powder obtained in C, SP, and PVDF to the ball milling tank at a mass ratio of 92.6:4.4:3, ball mill for 20 min at 180 r / min of the ball mill, coat it to a thickness of 120 μm, dry and slice it, and bake it in a vacuum at 90 °C for 12 h. The prepared electrode sheet is the positive electrode of the half-cell, the lithium sheet is the negative electrode, and 1 mol / L LiPF6 in EC / DEC / DMC (volume ratio 1:1:1) is used as the electrolyte to make a CR2032 type button cell.

[0067] Through this method, the capacity utilization of the inorganic substances coated in the material is greatly improved. The button cell is tested and charged and discharged at a current density of 33 mA / g. The first reversible capacity of the battery is 370 mAh / g.

[0068] Example 28 This example provides a method for preparing a lithium battery anode material of copper-doped silicon oxide-coated carbon, including: 1. Weigh 100.00 g of absolute ethanol, pour it into a beaker, then add 2.25 g of water, stir, add 15.00 g of graphite, stir, and then successively add 13.01 g of tetraethyl orthosilicate, 1.53 g of acetylacetone copper, 1.87 g of citric acid, and 0.49 g of dicyandiamide. After stirring, pour it into the inner liner of the reaction kettle and seal the homogeneous reaction kettle; 2. Heat the homogeneous reactor to 180 °C and react for 5 h. After the reaction, soak it in water for 20 min for rapid cooling, and then spray-dry; 3. Put the solid obtained above into a tube furnace, heat it up at a rate of 5 °C / min under a N2 atmosphere, keep it at 700 °C for 5 h, and finally cool it down to 300 °C at a rate of 5 °C / min and then cool it naturally to obtain a powder sample.

[0069] Example 29 This example provides a method for preparing a lithium battery anode material of copper-doped silicon oxide-coated carbon, including: 1. Weigh 100.00 g of absolute ethanol, pour it into a beaker, then add 2.25 g of water, stir, add 15.00 g of graphite, stir, and then successively add 13.01 g of tetraethyl orthosilicate, 1.53 g of acetylacetone copper, 1.87 g of citric acid, and 0.76 g of polyacrylonitrile solution (NMP solution with a concentration of 10%). After stirring, pour it into the inner liner of the autoclave and seal the homogeneous reactor; 2. Heat the homogeneous reactor to 180 °C and react for 5 h. After the reaction, soak it in water for 20 min for rapid cooling, and then spray dry; 3. Put the solid obtained above into a tube furnace, heat it up at a rate of 5 °C / min under a N2 atmosphere, keep it at 700 °C for 5 h, and finally cool it down to 300 °C at a rate of 5 °C / min and then cool it naturally to obtain a powder sample.

[0070] The above are only the preferred embodiments of the present application and are not used to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

[0071] The above embodiments are illustrative of the present application, not limiting of the present application. Any simply transformed scheme of the present application belongs to the protection scope of the present application.

Claims

1. A copper-doped silicon oxide-coated carbon lithium battery anode material, characterized in that, The molar ratio of the silicon element to the copper element is 2.5:1 to 12:1, and the content of carbon is 50%-99% of the total mass of the lithium battery anode material of copper-doped silicon oxide-coated carbon; The microstructure of the lithium battery anode material of copper-doped silicon oxide-coated carbon is a layered structure, with the outer layer being copper-doped silicon oxide and the inner layer being carbon; The copper-doped silicon oxide is in the form of particles or fiber meshes, and the particle size is between 10-100 nm.

2. A preparation method of a lithium battery anode material coated with copper-doped silicon oxide and carbon, characterized in that, It includes the following steps: S1: Sequentially take a calculated amount of ethanol, ethylene glycol, carbon, water, organic acid, organosilicon, copper salt, and catalyst, add them to a beaker and stir to mix evenly to obtain a mixed solution; S2: Introduce the mixed solution into a reaction kettle, carry out a homogeneous reaction at a certain temperature, and then cool to obtain a suspension; S3: Dry the suspension to obtain a precursor, and sinter the precursor at a high temperature in an inert atmosphere to obtain the lithium battery anode material of copper-doped silicon oxide-coated carbon.

3. The preparation method of the copper-doped silicon oxide-coated carbon lithium battery anode material according to claim 2, wherein, In step S1, the mass percentage of ethylene glycol to ethanol is 1:99-85:

15.

4. The preparation method of the copper-doped silicon oxide-coated carbon lithium battery anode material according to claim 2, characterized in that, In step S1, the carbon material is at least one of graphite, hard carbon, and soft carbon.

5. The preparation method of the copper-doped silicon oxide-coated carbon lithium battery anode material according to claim 2, characterized in that, In step S1, the catalyst is one of an acidic catalyst or a basic catalyst.

6. The preparation method of the copper-doped silicon oxide-coated carbon lithium battery anode material according to claim 5, characterized in that, In step S1, the acidic catalyst is selected from at least one of citric acid, polyacrylic acid, phosphoric acid, pyrophosphoric acid, and phytic acid.

7. The preparation method of the copper-doped silicon oxide-coated carbon lithium battery anode material according to claim 6, characterized in that, In the acidic catalyst, phosphoric acid, pyrophosphoric acid, and phytic acid are phosphorus-containing catalysts, and the molar ratio of the copper element to the phosphorus element in the phosphorus-containing catalyst is 0.08-2.

1.

8. The preparation method of the copper-doped silicon oxide-coated carbon lithium battery anode material according to claim 5, characterized in that, The basic catalyst is selected from one or more of aniline, dicyandiamide, and polyacrylonitrile.

9. The preparation method of the copper-doped silicon oxide-coated carbon lithium battery anode material according to claim 8, characterized in that, The molar ratio of the copper element to the nitrogen element in the basic catalyst is 0.06-1.

1.

10. The preparation method of the copper-doped silicon oxide-coated carbon lithium battery anode material according to claim 2, characterized in that, In step S1, the organosilicon is selected from one or more of methyl silicate, ethyl silicate, propyl silicate, and mixed silicate (the hydrocarbon groups in the silicate ester have different carbon numbers and structures).

11. The preparation method of the copper-doped silicon oxide-coated carbon lithium battery anode material according to claim 2, characterized in that, In step S1, the copper salt is selected from copper organic carboxylate or copper acetylacetonate.

12. The preparation method of the copper-doped silicon oxide-coated carbon lithium battery anode material according to claim 2, characterized in that, The molar ratio value range of water to the silicon element in step S1 is 1-8.

13. The preparation method of the copper-doped silicon oxide-coated carbon lithium battery anode material according to claim 2, characterized in that The molar ratio value range of ethylene glycol to the silicon element in step S1 is 15-0.

14. The preparation method of the copper-doped silicon oxide-coated carbon lithium battery anode material according to claim 2, characterized in that, In step S1, the organic acid is selected from citric acid or polyacrylic acid.

15. The preparation method of the copper-doped silicon oxide-coated carbon lithium battery anode material according to claim 2, characterized in that, In step S2, the reaction temperature is selected from 160°C-200°C.

16. The preparation method of the copper-doped silicon oxide-coated carbon lithium battery anode material according to claim 2, characterized in that, In step S3, the drying method is selected from one of suction filtration drying and spray drying.

17. The preparation method of the copper-doped silicon oxide-coated carbon lithium battery anode material according to claim 2, characterized in that, In step S3, the inert atmosphere is selected from one of a nitrogen atmosphere and an argon atmosphere.

18. The preparation method of the copper-doped silicon oxide-coated carbon lithium battery anode material according to claim 2, characterized in that, In step S3, the high sintering temperature is selected from 500°C-1100°C.

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