Carbon-lithium oxide composite electrode material, preparation method and application thereof

Abstract

The present invention relates to a carbon-lithium oxide composite electrode material and its preparation and application. The preparation method of the carbon-lithium oxide composite electrode material comprises the following steps: mixing activated carbon with a lithium source to obtain a first mixture; wherein, the lithium source is at least one of lithium oxalate, lithium carbonate, squaric acid lithium, and lithium nitrate. Heat-treat the first mixture in an atmosphere of a protective gas, and the heat-treatment temperature is 600°C to 800°C. In this preparation method, the lithium supplementation amount of the composite electrode material can be controlled by controlling the mass ratio of the activated carbon to the lithium source. Compared with traditional prelithiation, this preparation method effectively reduces the control difficulty of the lithium supplementation amount and can also improve the accuracy of the lithium supplementation amount. In addition, in this preparation method, through the activation of carbon dioxide, the capacitance of the composite electrode material can be increased, thereby improving the energy density of the composite electrode material.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium energy storage, and particularly relates to a carbon-lithium oxide composite electrode material and its preparation and application. Background Art

[0002] Lithium-ion capacitors combine the high energy density of lithium-ion batteries and the high power and long life of supercapacitors, and currently have relatively wide applications in fields such as high-power charge and discharge, wind power generation, and uninterruptible power supply (UPS). Generally, activated carbon is used as the positive electrode and graphite or the like is used as the negative electrode in lithium-ion capacitors. During the charge and discharge process, lithium ions in the electrolyte are inserted / extracted at the negative electrode, and anions in the electrolyte are adsorbed / desorbed at the positive electrode to form an electric double layer.

[0003] The electrode active materials of lithium-ion capacitors do not contain lithium, so it is necessary to introduce a lithium source through a prelithiation method. By prelithiating the electrode material during the preparation process of the electrode material, the voltage of the lithium-ion capacitor can be increased, thereby increasing the energy density of the lithium-ion capacitor. In the traditional prelithiation process, methods such as introducing lithium powder, lithium tape, or prelithiation agent are often used for prelithiation. Although such methods can achieve good prelithiation effects, they all have certain limitations. For example, the high reaction activity of lithium powder or lithium tape makes the prelithiation process difficult to control, and ultimately the amount of lithium supplementation is difficult to control. And the products after the reaction of the prelithiation agent are mostly inert, which will bring certain restrictions to the improvement of the energy density of the lithium-ion capacitor. Summary of the Invention

[0004] Based on this, it is necessary to provide a preparation method of an electrode material with an easily controllable lithium supplementation amount and capable of increasing the energy density, as well as a carbon-lithium oxide composite electrode material obtained by the preparation method and its application.

[0005] In order to solve the above technical problems, the technical solution of the present invention is as follows:

[0006] A preparation method of a carbon-lithium oxide composite electrode material, comprising the following steps:

[0007] Mix activated carbon with a lithium source to obtain a first mixture; wherein, the lithium source is at least one of lithium oxalate, lithium carbonate, squaric acid lithium, and lithium nitrate;

[0008] Under a protective gas atmosphere, perform heat treatment on the first mixture, and the temperature of the heat treatment is 600°C to 800°C.

[0009] In one embodiment, the mass ratio of the activated carbon to the lithium source is 1:0.5 to 1:5.

[0010] In one embodiment, when the first mixture is heat-treated, it is heated to 600 °C to 800 °C at a heating rate of 0.5 °C / min to 10 °C / min; and / or,

[0011] The time of the heat treatment is 1 h to 4 h.

[0012] In one embodiment, the method for preparing the activated carbon includes the following steps:

[0013] Mix a carbon precursor with a pore-forming agent to obtain a second mixture;

[0014] In an atmosphere of a protective gas, the second mixture is carbonized, and the temperature of the carbonization treatment is 200 °C to 800 °C.

[0015] In one embodiment, the mass ratio of the carbon precursor to the pore-forming agent is 1:0.5 to 1:5.

[0016] In one embodiment, when the second mixture is carbonized, it is heated to 200 °C to 800 °C at a heating rate of 0.5 °C / min to 10 °C / min; and / or,

[0017] The time of the carbonization treatment is 1 h to 4 h.

[0018] In one embodiment, the carbon precursor is at least one of fruit shell, wood, feather, pitch, and coal; and / or,

[0019] The pore-forming agent is at least one of potassium hydroxide, sodium hydroxide, zinc chloride, and phosphoric acid.

[0020] A carbon-lithium oxide composite electrode material, the particles of which comprise a carbon substrate and lithium oxide nanomaterials, and the lithium oxide nanomaterials protrude from the surface of the carbon substrate.

[0021] In one embodiment, the shape of the lithium oxide nanomaterials is at least one of linear, tubular, sheet-like, and strip-like. [[ID=�5]]

[0022] In one embodiment, the mass percentage of the lithium oxide nanomaterials in the carbon-lithium oxide composite electrode material is 15% to 60%.

[0023] A lithium-ion capacitor, the positive electrode material of which comprises the carbon-lithium oxide composite electrode material obtained by the preparation method described in any one of the above embodiments; or the positive electrode material of which comprises the carbon-lithium oxide composite electrode material described in any one of the above embodiments.

[0024] The preparation method of the above carbon-lithium oxide composite electrode material comprises the following steps: mixing activated carbon with a lithium source to obtain a first mixture; wherein, the lithium source is at least one of lithium oxalate, lithium carbonate, squaric acid lithium, and lithium nitrate. Heat-treat the first mixture in an atmosphere of a protective gas, and the heat-treatment temperature is 600°C to 800°C. In the above preparation method, the mixture obtained by mixing activated carbon and a lithium source is heat-treated at a temperature of 600°C to 800°C. During the heat-treatment process, lithium oxide and carbon dioxide are generated, and the generated lithium oxide and carbon dioxide can respectively play the roles of prelithiation and activation on the composite electrode material. In the above preparation method, the amount of lithium supplementation of the composite electrode material can be controlled by controlling the mass ratio of activated carbon to the lithium source. Compared with traditional prelithiation, the above preparation method effectively reduces the control difficulty of the amount of lithium supplementation, and at the same time can also improve the accuracy of the amount of lithium supplementation. In addition, in the above preparation method, through the activation of carbon dioxide, the capacitance of the composite electrode material can be increased, thereby increasing the energy density of the composite electrode material.

[0025] The particles of the above carbon-lithium oxide composite electrode material include a carbon substrate and lithium oxide nanomaterials, and the lithium oxide nanomaterials protrude from the surface of the carbon substrate. This composite electrode material has a high capacitance, and applying it to a lithium-ion capacitor can effectively improve the energy density and power density of the lithium-ion capacitor. Description of the Drawings

[0026] Figure 1 It is the electron microscope image of the carbon-lithium oxide composite electrode material obtained in Example 1 of the present invention;

[0027] Figure 2 It is the electron microscope image of the electrode material obtained in Comparative Example 1 of the present invention;

[0028] Figure 3 It is the energy density-power density curve of the lithium-ion capacitors in Example 1 and Comparative Example 1 of the present invention. Detailed Embodiments

[0029] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following describes the detailed embodiments of the present invention in conjunction with the accompanying drawings. Many specific details are set forth in the following description in order to fully understand the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0030] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this invention belongs. The terms used in the description of the present invention herein are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0032] An embodiment of the present invention provides a method for preparing a carbon-lithium oxide composite electrode material. The preparation method includes the following steps: mixing activated carbon with a lithium source to obtain a first mixture; wherein the lithium source is at least one of lithium oxalate, lithium carbonate, squaric acid lithium, and lithium nitrate. Under a protective gas atmosphere, the first mixture is heat-treated at a temperature of 600°C to 800°C. In the preparation method of this embodiment, the mixture obtained by mixing activated carbon and a lithium source is heat-treated at a temperature of 600°C to 800°C, and lithium oxide and carbon dioxide are generated during the heat treatment process. The generated lithium oxide and carbon dioxide can respectively play the roles of prelithiation and activation for the composite electrode material. In the preparation method of this embodiment, the prelithiation amount of the composite electrode material can be controlled by controlling the mass ratio of activated carbon to the lithium source. Compared with traditional prelithiation, the preparation method of this embodiment effectively reduces the control difficulty of the prelithiation amount and can also improve the accuracy of the prelithiation amount. In addition, in the preparation method of this embodiment, through the activation of carbon dioxide, the capacitance of the composite electrode material can be increased, thereby improving the energy density of the composite electrode material. It can be understood that both the activated carbon and the lithium source can be commercially available products.

[0033] In a specific example, another embodiment of the present invention provides a method for preparing a carbon-lithium oxide composite electrode material. The preparation method is: mixing activated carbon with a lithium source to obtain a first mixture; wherein the lithium source is at least one of lithium oxalate, lithium carbonate, squaric acid lithium, and lithium nitrate. Under a protective gas atmosphere, the first mixture is heat-treated at a temperature of 600°C to 800°C. After the heat treatment, the carbon-lithium oxide composite electrode material in this embodiment is obtained.

[0034] Further, when mixing activated carbon with a lithium source, the mass ratio of activated carbon to the lithium source can effectively control the amount of lithium supplementation for the composite electrode material. Specifically, the mass ratio of activated carbon to the lithium source is 1:0.5 to 1:5. Optionally, the mass ratio of activated carbon to the lithium source is 1:0.5 to 1:2. For example, the mass ratio of activated carbon to the lithium source is 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:2, 1:2.1, 1:2.2, 1:2.3, 1:2.4, 1:2.5, 1:2.6, 1:2.7, 1:2.8, 1:2.9, 1:3, 1:3.1, 1:3.2, 1:3.3, 1:3.4, 1:3.5, 1:3.6, 1:3.7, 1:3.8, 1:3.9, 1:4, 1:4.1, 1:4.2, 1:4.3, 1:4.4, 1:4.5, 1:4.6, 1:4.7, 1:4.8, 1:4.9, 1:5. It can be understood that when mixing activated carbon with the lithium source, other suitable selections can also be made within the range of 1:0.5 to 1:5 for the mass ratio of activated carbon to the lithium source.

[0035] Still further, after mixing activated carbon and the lithium source, the following steps are further included: performing a grinding treatment on the first mixture. The way of grinding treatment can be ball milling or the like. Specifically, the particle size of the first mixture after grinding is 1 μm to 100 μm.

[0036] As the temperature selection for heat treatment, the temperature for heat treatment can be but is not limited to 600 °C, 610 °C, 620 °C, 630 °C, 640 °C, 650 °C, 660 °C, 670 °C, 680 °C, 690 °C, 700 °C, 710 °C, 720 °C, 730 °C, 740 °C, 750 °C, 760 °C, 770 °C, 780 °C, 790 °C or 800 °C. It can be understood that other suitable selections can also be made within the range of 600 °C to 800 °C for the temperature of heat treatment.

[0037] In a specific example, when performing heat treatment on the first mixture, the temperature is usually raised from the base temperature to the heat treatment temperature. For example, the temperature is raised from room temperature to the heat treatment temperature. During this heating process, the magnitude of the heating rate also has a greater impact on the effect of the heat treatment. If the heating rate is too slow, it will result in a long heating time, low production efficiency, or more by-products. If the heating rate is too large, it may cause uneven reactions inside the first mixture, which is also not conducive to the improvement of the composite electrode material. Specifically, when performing heat treatment on the first mixture, it is heated to 600°C to 800°C at a heating rate of 0.5°C / min to 10°C / min. That is, when performing heat treatment on the first mixture, it is heated to the heat treatment temperature at a heating rate of 0.5°C / min to 10°C / min. Optionally, the heating rate is 0.5°C / min, 0.6°C / min, 0.7°C / min, 0.8°C / min, 0.9°C / min, 1°C / min, 1.2°C / min, 1.5°C / min, 1.8°C / min, 2°C / min, 2.2°C / min, 2.5°C / min, 2.8°C / min, 3°C / min, 3.2°C / min, 3.5°C / min, 3.8°C / min, 4°C / min, 4.2°C / min, 4.5°C / min, 4.8°C / min, 5°C / min, 5.2°C / min, 5.5°C / min, 5.8°C / min, 6°C / min, 6.2°C / min, 6.5°C / min, 6.8°C / min, 7°C / min, 7.2°C / min, 7.5°C / min, 7.8°C / min, 8°C / min, 8.2°C / min, 8.5°C / min, 8.8°C / min, 9°C / min, 9.2°C / min, 9.5°C / min, 9.8°C / min or 10°C / min. It can be understood that other appropriate selections can also be made for the heating rate within the range of 0.5°C / min to 10°C / min.

[0038] In a specific example, as the selection of the heat treatment time, the heat treatment time is 1 h to 4 h. Specifically, the heat treatment time can be, but is not limited to, 1 h, 1.1 h, 1.2 h, 1.3 h, 1.4 h, 1.5 h, 1.6 h, 1.7 h, 1.8 h, 1.9 h, 2 h, 2.1 h, 2.2 h, 2.3 h, 2.4 h, 2.5 h, 2.6 h, 2.7 h, 2.8 h, 2.9 h, 3 h, 3.1 h, 3.2 h, 3.3 h, 3.4 h, 3.5 h, 3.6 h, 3.7 h, 3.8 h, 3.9 h, 4 h. Of course, other appropriate selections can also be made for the heat treatment time within the range of 1 h to 4 h.

[0039] It is understandable that the first mixture is heat-treated in an inert gas atmosphere. At this time, the inert gas is at least one of nitrogen, helium, neon, argon, krypton, and xenon.

[0040] It is also understandable that the heat treatment can be carried out in a tube furnace. That is, the first mixture is placed in the tube furnace, and the first mixture is heat-treated in the tube furnace. Specifically, the first mixture is placed in the tube furnace, and a heating program is set, and then the first mixture is heat-treated. More specifically, when setting the heating program, the heating rate is 0.5 °C / min to 10 °C / min, and the heat treatment temperature is 600 °C to 800 °C.

[0041] It is also understandable that after the heat treatment, the following steps are included: cleaning the first mixture after the heat treatment. Specifically, the first mixture after the heat treatment is cleaned until the cleaning solution is neutral. More specifically, the first mixture after the heat treatment is successively cleaned with a dilute acid solution and water until the water is neutral. Even more specifically, the first mixture after the heat treatment is cleaned with dilute acid and water in a cycle until the water is neutral. Even more specifically, the dilute acid solution can be dilute nitric acid, dilute sulfuric acid, dilute hydrochloric acid, etc. Of course, after cleaning the first mixture after the heat treatment, steps of filtering and drying the first mixture are also included.

[0042] In a specific example, the preparation method of activated carbon includes the following steps: mixing a carbon precursor and a pore-forming agent to obtain a second mixture. The second mixture is carbonized in an inert gas atmosphere, and the carbonization temperature is 200 °C to 800 °C. Optionally, the carbonization temperature can be, but is not limited to, 200 °C, 210 °C, 220 °C, 230 °C, 240 °C, 250 °C, 260 °C, 270 °C, 280 °C, 290 °C, 300 °C, 310 °C, 320 °C, 330 °C, 340 °C, 350 °C, 360 °C, 370 °C, 380 °C, 390 °C, 400 °C, 410 °C, 420 °C, 430 °C, 440 °C, 450 °C, 460 °C, 470 °C, 480 °C, 490 °C, 500 °C, 510 °C, 520 °C, 530 °C, 540 °C, 550 °C, 560 °C, 570 °C, 580 °C, 590 °C, 600 °C, 610 °C, 620 °C, 630 °C, 640 °C, 650 °C, 660 °C, 670 °C, 680 °C, 690 °C, 700 °C, 710 °C, 720 °C, 730 °C, 740 °C, 750 °C, 760 °C, 770 °C, 780 °C, 790 °C, 800 °C. It is understandable that other suitable selections can also be made for the carbonization temperature within the range of 200 °C to 800 °C.

[0043] Further, when mixing the carbon precursor with the pore-forming agent, the mass ratio of the carbon precursor to the pore-forming agent is 1:0.5 to 1:5. For example, the mass ratio of the carbon precursor to the pore-forming agent is 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:2, 1:2.1, 1:2.2, 1:2.3, 1:2.4, 1:2.5, 1:2.6, 1:2.7, 1:2.8, 1:2.9, 1:3, 1:3.1, 1:3.2, 1:3.3, 1:3.4, 1:3.5, 1:3.6, 1:3.7, 1:3.8, 1:3.9, 1:4, 1:4.1, 1:4.2, 1:4.3, 1:4.4, 1:4.5, 1:4.6, 1:4.7, 1:4.8, 1:4.9, 1:5. It can be understood that when mixing the carbon precursor with the pore-forming agent, other suitable selections can also be made within the range of 1:0.5 to 1:5 for the mass ratio of the carbon precursor to the pore-forming agent.

[0044] Still further, after mixing the carbon precursor and the pore-forming agent, the following steps are further included: grinding the second mixture. The grinding method can be ball milling or the like. Specifically, the particle size of the second mixture after grinding is 1 μm to 100 μm.

[0045] In a specific example, when carbonizing the second mixture, the temperature is usually raised from a base temperature to a carbonization temperature. For example, the temperature is raised from room temperature to the carbonization temperature. During this heating process, the magnitude of the heating rate also has a greater impact on the effect of the carbonization treatment. If the heating rate is too slow, it will result in a long heating time, low production efficiency, or more by-products. If the heating rate is too high, it may cause uneven reactions inside the second mixture and is also not conducive to the improvement of the composite electrode material. Specifically, when carbonizing the second mixture, it is heated to 200°C to 800°C at a heating rate of 0.5°C / min to 10°C / min. That is, when carbonizing the second mixture, it is heated to the carbonization treatment temperature at a heating rate of 0.5°C / min to 10°C / min. Optionally, the heating rate is 0.5°C / min, 0.6°C / min, 0.7°C / min, 0.8°C / min, 0.9°C / min, 1°C / min, 1.2°C / min, 1.5°C / min, 1.8°C / min, 2°C / min, 2.2°C / min, 2.5°C / min, 2.8°C / min, 3°C / min, 3.2°C / min, 3.5°C / min, 3.8°C / min, 4°C / min, 4.2°C / min, 4.5°C / min, 4.8°C / min, 5°C / min, 5.2°C / min, 5.5°C / min, 5.8°C / min, 6°C / min, 6.2°C / min, 6.5°C / min, 6.8°C / min, 7°C / min, 7.2°C / min, 7.5°C / min, 7.8°C / min, 8°C / min, 8.2°C / min, 8.5°C / min, 8.8°C / min, 9°C / min, 9.2°C / min, 9.5°C / min, 9.8°C / min or 10°C / min. It can be understood that other suitable selections can also be made for the heating rate within the range of 0.5°C / min to 10°C / min.

[0046] It can be understood that the second mixture is carbonized in an atmosphere of protective gas. At this time, the protective gas is at least one of nitrogen, helium, neon, argon, krypton, and xenon.

[0047] It can also be understood that the carbonization treatment can be carried out in a tube furnace. That is, the second mixture is placed in the tube furnace, and the second mixture is heat-treated in the tube furnace. Specifically, the second mixture is placed in the tube furnace, and a heating program is set, and then the second mixture is carbonized. More specifically, when setting the heating program, the heating rate is 0.5°C / min to 10°C / min, and the carbonization treatment temperature is 200°C to 800°C.

[0048] It can also be understood that after the carbonization treatment, the following steps are further included: cleaning the second mixture after the carbonization treatment. Specifically, the second mixture after the carbonization treatment is cleaned until the cleaning liquid is neutral. More specifically, the second mixture after the carbonization treatment is successively cleaned with a dilute acid solution and water until the water is neutral. Even more specifically, the second mixture after the carbonization treatment is cleaned cyclically with dilute acid and water until the water is neutral. Even more specifically, the dilute acid solution can be dilute nitric acid, dilute sulfuric acid, dilute hydrochloric acid, etc. Of course, after cleaning the second mixture after the heat treatment, the steps of filtering and drying the second mixture are further included.

[0049] In a specific example, the carbon precursor is at least one of fruit shell, wood, feather, pitch, and coal. At this time, the waste carbon precursor can be recycled.

[0050] In a specific example, the pore-forming agent is at least one of potassium hydroxide, sodium hydroxide, zinc chloride, and phosphoric acid.

[0051] It can be understood that in the present invention, the mixing of the activated carbon and the lithium source, the heat treatment, the mixing of the carbon precursor and the pore-forming agent, and the carbonization treatment can all be carried out by means of solid mixing and solid-phase reaction.

[0052] Another embodiment of the present invention provides a carbon-lithium oxide composite electrode material. This carbon-lithium oxide composite electrode material is prepared by the preparation method of the above carbon-lithium oxide composite electrode material.

[0053] Another embodiment of the present invention provides a carbon-lithium oxide composite electrode material. The particles of this composite electrode material include a carbon substrate and lithium oxide nanomaterials, and the lithium oxide nanomaterials protrude from the surface of the carbon substrate. This composite electrode material has a relatively high capacitance, and applying it to a lithium-ion capacitor can effectively improve the energy density and power density of the lithium-ion capacitor.

[0054] Furthermore, the shape of the lithium oxide nanomaterials is at least one of linear, tubular, sheet-like, and strip-like.

[0055] Still further, the mass percentage of the lithium oxide nanomaterials in the carbon-lithium oxide composite electrode material is 15% - 60%. For example, the mass percentage of the lithium oxide nanomaterials in the carbon-lithium oxide composite electrode material is 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, or 60%, etc. It can be understood that the mass percentage of the lithium oxide nanomaterials in the carbon-lithium oxide composite electrode material can also make other suitable selections within the range of 15% - 60%.

[0056] Another embodiment of the present invention provides a carbon-lithium oxide composite electrode material obtained by the above preparation method and / or an application of the carbon-lithium oxide composite electrode material obtained by the above preparation method as a positive electrode material of a lithium-ion energy storage device.

[0057] Furthermore, another embodiment of the present invention provides an application of a carbon-lithium oxide composite electrode material obtained by the above preparation method and / or the carbon-lithium oxide composite electrode material obtained by the above preparation method as a positive electrode material of a lithium-ion capacitor.

[0058] Still further, another embodiment of the present invention provides a lithium-ion capacitor. The positive electrode material of the lithium-ion capacitor includes the carbon-lithium oxide composite electrode material obtained by the above preparation method; or the positive electrode material of the lithium-ion capacitor includes the above carbon-lithium oxide composite electrode material.

[0059] The following are specific examples.

[0060] Example 1

[0061] The preparation method of the carbon-lithium oxide composite electrode material in this example includes the following steps:

[0062] S101: Wash the waste duck feathers with water and dry them as the carbon precursor. Then mix the carbon precursor with potassium hydroxide in a mass ratio of 1:4 and grind. The particle size of the mixture after grinding is 1 μm to 100 μm.

[0063] S102: Place the mixture ground in S101 in a tube furnace, and under an argon atmosphere, heat it to 800 °C at a heating rate of 5 °C / min, and the carbonization treatment time is 1 h.

[0064] S103: Wash the product obtained in S102 with dilute nitric acid and deionized water in a cycle until the deionized water after washing is neutral (pH = 7), then filter by suction and dry in an oven.

[0065] S104: Mix the product obtained in S103 with lithium oxalate in a mass ratio of 1:1 and grind. The particle size of the mixture after grinding is 1 μm to 100 μm.

[0066] S105: Place the product ground in S104 in a tube furnace, and under an argon atmosphere, heat it to 800 °C at a heating rate of 5 °C / min, and the heat treatment time is 1 h.

[0067] S106: Wash the product obtained in S105 with dilute nitric acid and deionized water in a cycle until the deionized water after washing is neutral (pH = 7), then filter by suction and dry in an oven. The carbon-lithium oxide composite electrode material in this example is obtained after drying. The electron micrograph of the carbon-lithium oxide composite electrode material is asFigure 1 As shown. After analysis, the carbon-lithium oxide composite electrode material includes a carbon substrate and lithium oxide nanomaterials extending from the surface of the carbon substrate.

[0068] Example 2

[0069] Compared with Example 1, the difference in this example is that in S104: the product obtained in S103 is mixed with lithium oxalate at a mass ratio of 1:2 and ground, and the particle size of the mixture after grinding is 1 μm to 100 μm.

[0070] Example 3

[0071] Compared with Example 1, the difference in this example is that in S104: the product obtained in S103 is mixed with lithium oxalate at a mass ratio of 1:0.5 and ground, and the particle size of the mixture after grinding is 1 μm to 100 μm.

[0072] Comparative Example 1

[0073] The preparation method of the electrode material in this comparative example includes the following steps:

[0074] S101: Wash the waste duck feathers with water and dry them as the carbon precursor. Then mix the carbon precursor with potassium hydroxide at a mass ratio of 1:4 and grind, and the particle size of the mixture after grinding is 1 μm to 100 μm.

[0075] S102: Place the mixture ground in S101 in a tube furnace, and under an argon atmosphere, heat it to 800 °C at a heating rate of 5 °C / min, and the carbonization treatment time is 1 h.

[0076] S103: Wash the product obtained in S102 with dilute nitric acid and deionized water in a cycle until the deionized water after washing is neutral (pH = 7), then filter by suction and dry in an oven. The electrode material in this comparative example is obtained after drying. The electron micrograph of the electrode material is as Figure 2 shown.

[0077] Comparative Example 2

[0078] Compared with Example 1, the difference in this comparative example is that the heat treatment temperature in S102 is 900 °C.

[0079] Test Example

[0080] S101: Dissolve the carbon-lithium oxide composite electrode material obtained in the examples and the electrode material obtained in the comparative examples with conductive carbon black and polyvinylidene fluoride (PVDF) at a mass ratio of 8:1:1 in N-methylpyrrolidone (NMP) to make a slurry, uniformly coat the slurry on the aluminum foil, and dry it in a vacuum drying oven to obtain the corresponding positive electrode plates respectively.

[0081] S102: Dissolve graphite, conductive carbon black, and PVDF in N-methylpyrrolidone (NMP) in a mass ratio of 8:1:1 to make a slurry. Uniformly coat the slurry on a copper foil and dry it in a vacuum drying oven to obtain the corresponding negative electrode plates respectively.

[0082] S103: Assemble the positive electrode plate and the negative electrode plate obtained in S101 and S102 into a lithium-ion capacitor, and the mass ratio of the positive electrode plate to the negative electrode plate is 2:1.

[0083] Perform energy density and power density tests on the lithium-ion capacitors corresponding to the examples and the comparative examples and the lithium-ion capacitors corresponding to the comparative examples respectively. The test results are shown in the following table. Among them, the energy density-power density curves of the lithium-ion capacitors corresponding to Example 1 and Comparative Example 1 are as Figure 3 shown.

[0084] Highest energy density (Wh / kg) Highest power density (kW / kg) Example 1 115.3 13.7 Example 2 131.6 9.3 Example 3 111.3 8.0 Comparative Example 1 40.4 1.2 Comparative Example 2 87.7 5.6

[0085] It can be seen that Figure 3 the highest energy density of the lithium-ion capacitor corresponding to Example 1 is 115.3 Wh / kg, and the highest power density is 13.7 kW / kg. The highest energy density of the lithium-ion capacitor corresponding to Comparative Example 1 is 40.4 Wh / kg, and the highest power density is 1.2 kW / kg. That is, the lithium-ion capacitor corresponding to Example 1 is significantly superior to the lithium-ion capacitor corresponding to Comparative Example 1 in terms of both energy density and power density performance.

[0086] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0087] The above-described embodiments only represent several implementation manners of the present invention. Their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the invention patent should be subject to the appended claims, and the specification and drawings can be used to explain the content of the claims.

Claims

1. A preparation method of a carbon-lithium oxide composite electrode material, characterized in that, It includes the following steps: Mix activated carbon with a lithium source to obtain a first mixture; wherein, the lithium source is at least one of lithium oxalate, lithium carbonate, squaric acid lithium, and lithium nitrate; the mass ratio of the activated carbon to the lithium source is 1:0.5 to 1:5; Under an inert gas atmosphere, perform heat treatment on the first mixture. The temperature of the heat treatment is 600°C to 800°C. During the heat treatment, carbon dioxide is generated to activate the composite electrode material; heat up to 600°C to 800°C at a heating rate of 0.5°C / min to 10°C / min, and the heat treatment time is 1h to 4h.

2. The preparation method of the carbon-lithium oxide composite electrode material according to claim 1, wherein The preparation method of the activated carbon includes the following steps: Mix a carbon precursor with a pore-forming agent to obtain a second mixture; Under an inert gas atmosphere, perform carbonization treatment on the second mixture. The temperature of the carbonization treatment is 200°C to 800°C.

3. The preparation method of the carbon-lithium oxide composite electrode material according to claim 2, characterized in that, The mass ratio of the carbon precursor to the pore-forming agent is 1:0.5 to 1:

5.

4. The preparation method of the carbon-lithium oxide composite electrode material according to claim 2, characterized in that, When performing carbonization treatment on the second mixture, heat up to 200°C to 800°C at a heating rate of 0.5°C / min to 10°C / min.

5. The preparation method of the carbon-lithium oxide composite electrode material according to claim 2, wherein, The time of the carbonization treatment is 1h to 4h.

6. The preparation method of the carbon-lithium oxide composite electrode material according to any one of claims 2 to 5, characterized in that, The carbon precursor is at least one of fruit shell, wood, feather, pitch, and coal.

7. The preparation method of the carbon-lithium oxide composite electrode material according to any one of claims 2 to 5, characterized in that The pore-forming agent is at least one of potassium hydroxide, sodium hydroxide, zinc chloride, and phosphoric acid.

8. A carbon-lithium oxide composite electrode material, characterized in that, Prepared by the preparation method of the carbon-lithium oxide composite electrode material according to any one of claims 1 to 7, its particles include a carbon substrate and lithium oxide nanomaterials, and the lithium oxide nanomaterials protrude from the surface of the carbon substrate.

9. The carbon-lithium oxide composite electrode material according to claim 8, wherein, The shape of the lithium oxide nanomaterials is at least one of linear, tubular, sheet-like, and strip-like; and / or, The mass percentage of the lithium oxide nanomaterials in the carbon-lithium oxide composite electrode material is 15% to 60%.

10. A lithium-ion capacitor, characterized in that, Its positive electrode material includes the carbon-lithium oxide composite electrode material according to any one of claims 8 to 9.

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