SiO / c negative electrode gas phase prelithiation method and device

Abstract

The application provides a SiO / C negative electrode gas-phase pre-lithiation method and device. The SiO / C negative electrode gas-phase pre-lithiation device comprises a reaction container (4) having a reaction cavity for containing SiO / C; a lithium source box (3) arranged in the reaction cavity and having a containing cavity and a gas outlet, the containing cavity is configured to contain a lithium source, and the gas outlet is in communication with the containing cavity; a first gas pipe (1) in communication with the reaction cavity; a second gas pipe (2) in communication with the lithium source box (3) and configured to introduce a protective gas into the containing cavity; and a heater configured to heat the reaction cavity. The SiO / C negative electrode gas-phase pre-lithiation method of the technical scheme of the application can be applied to pre-lithiation of SiO / C material, can improve the initial efficiency, and is environmentally friendly.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lithium batteries, in particular to a SiO / C negative electrode gas-phase pre-lithiation method and device. BACKGROUND

[0002] The traditional graphite negative electrode cannot meet the demand for higher energy density in the design of the battery cell, and the silicon monoxide negative electrode has a high specific capacity and is considered to be the most promising new generation of negative electrode material, but it also has some defects and cannot be applied on a large scale. When the silicon monoxide negative electrode is embedded with lithium, the expansion reaches 200%, and the material is easily pulverized and fails during the cycle process. A large amount of irreversible lithium silicate is formed during the first lithium embedding, resulting in a low initial efficiency.

[0003] For the problem of low initial efficiency, the pre-lithiation method is usually used to reduce the consumption of lithium source in the full battery and improve the initial efficiency by reacting SiO / C with the lithium source in advance. The pre-lithiation method is usually a solid-phase sintering method and a liquid-phase pre-lithiation method. The solid-phase sintering method is to mix the lithium source with SiO / C and then calcine at high temperature. This method is simple, but the uniformity of the mixture is difficult to control, and the crystal grain size increases obviously during the calcination process. The liquid-phase pre-lithiation method is to dissolve the lithium source in an organic solvent and then mix it with SiO / C, and finally calcine. This method has good mixing uniformity and can effectively control the crystal grain growth, but it involves organic solvents, which are not environmentally friendly and are difficult to dispose of.

[0004] In summary, the above technologies lack a new pre-lithiation process that can be applied to SiO / C materials, which not only improves the initial efficiency but also is environmentally friendly. SUMMARY

[0005] The main purpose of the present application is to provide a SiO / C negative electrode gas-phase pre-lithiation method and device, which can be applied to the pre-lithiation of SiO / C materials, can improve the initial efficiency, and is environmentally friendly.

[0006] In order to achieve the above purpose, according to one aspect of the present application, a SiO / C negative electrode gas-phase pre-lithiation device is provided, comprising:

[0007] A reaction container having a reaction cavity for containing SiO / C;

[0008] A lithium source box arranged in the reaction cavity and having a containing cavity configured to contain a lithium source and a gas outlet communicating with the containing cavity;

[0009] A first gas pipe communicating with the reaction cavity;

[0010] A second gas pipe communicating with the lithium source box and configured to introduce a protective gas into the containing cavity;

[0011] A heater configured to heat the reaction cavity.

[0012] Further, the SiO / C negative electrode gas phase pre-lithium device further comprises a rotary driving device, which is drivingly connected with the reaction container to drive the reaction container to rotate.

[0013] Further, a turnover plate is arranged on the inner side wall of the reaction container and protrudes from the inner side wall to the center of the reaction container.

[0014] Further, an installation port is arranged at the end of the reaction container, and the installation port is provided with an installation plug, the installation plug is rotatable relative to the reaction container, and the first gas pipe and the second gas pipe are both installed on the installation plug.

[0015] Further, a sealable door is arranged on the reaction container, the door is configured to place the lithium source and / or SiO / C into the lithium source box; and / or, the second gas pipe is communicated to the bottom of the lithium source box, and the top of the lithium source box is provided with a gas outlet.

[0016] Further, an outlet is arranged at the end of the reaction container, and a plugging structure is arranged at the outlet to open or close the outlet; and / or, the protective gas is at least one of helium, neon, argon, krypton, xenon and radon.

[0017] According to another aspect of the present application, a SiO / C negative electrode gas phase pre-lithium method is provided, which uses the SiO / C negative electrode gas phase pre-lithium device described above, and comprises:

[0018] placing the SiO / C into the reaction cavity of the reaction container;

[0019] placing the lithium source into the lithium source box;

[0020] using the first gas pipe to introduce the protective gas into the reaction cavity to displace the air in the reaction cavity;

[0021] heating the reaction cavity to make the temperature in the reaction cavity reach a first preset temperature, wherein the first preset temperature is above the melting point of the lithium source;

[0022] making the lithium source vapor react with the SiO / C for a preset time to generate a reaction material.

[0023] Further, after the step of making the temperature in the reaction cavity reach the first preset temperature, and before the step of making the lithium source vapor react with the SiO / C for a preset time, the SiO / C negative electrode gas phase pre-lithium method further comprises:

[0024] using the second gas pipe to introduce the protective gas into the lithium source box to blow the lithium source vapor into the reaction cavity.

[0025] Further, the SiO / C negative electrode gas phase pre-lithium method further comprises:

[0026] After the reaction of the lithium source vapor and the SiO / C is completed, the reaction cavity is cooled down, and the second gas pipe is closed;

[0027] When the temperature in the reaction cavity drops to the preset temperature, the first gas pipe is closed;

[0028] The reaction material is discharged from the discharge port.

[0029] Further, the SiO / C negative electrode gas phase pre-lithium method further comprises:

[0030] After the reaction of the lithium source vapor and the SiO / C is completed, the temperature of the reaction cavity is raised to a second preset temperature, wherein the second preset temperature is greater than the first preset temperature;

[0031] The gas source of the first gas pipe is switched, and the mixed gas of the protective gas and the carbon source gas is introduced into the reaction cavity through the first gas pipe, and the temperature is kept for a preset time;

[0032] The gas source of the first gas pipe is switched, and the protective gas is introduced into the reaction cavity through the first gas pipe;

[0033] When the temperature in the reaction cavity drops to the preset temperature, the first gas pipe is closed;

[0034] The reaction material is discharged from the discharge port.

[0035] Further, the preset time for the reaction of the lithium source vapor and the SiO / C is 2h-15h, and the temperature is kept at 400℃-1000℃.

[0036] Further, the lithium source is at least one of metallic lithium, lithium oxide, lithium carbonate, lithium hydroxide, lithium acetate, lithium azide and butyl lithium; and / or, the material of the reaction container is a high-temperature resistant and corrosion-resistant material.

[0037] Further, the carbon source gas is at least one of acetylene, methane and toluene.

[0038] The SiO / C negative electrode gas-phase prelithiation device of the technical scheme of the present application comprises: a reaction container having a reaction cavity for containing SiO / C; a lithium source box arranged in the reaction cavity and having a containing cavity configured to contain a lithium source and a gas outlet in communication with the containing cavity; a first gas pipe in communication with the reaction cavity; a second gas pipe in communication with the lithium source box and configured to introduce protective gas into the containing cavity; and a heater configured to heat the reaction cavity. The SiO / C negative electrode gas-phase prelithiation device can replace the gas environment in the reaction cavity by using the first gas pipe, melt the lithium source by using the heater, and then blow the lithium source into the reaction cavity in a gaseous state to react with SiO / C, thereby realizing gas-phase prelithiation of SiO / C. After the lithium source is in a gaseous state, the concentration is low, and the reaction with SiO / C is relatively mild, which can effectively inhibit the growth of the grain size, thereby effectively improving the initial efficiency, and the present application does not involve organic solvents, is environmentally friendly, has low post-processing difficulty, and is green and environmentally friendly. BRIEF DESCRIPTION OF DRAWINGS

[0039] The accompanying drawings, which form a part of this application, are included to provide a further understanding of the application, illustrate the preferred embodiments of the application and assist in explaining the application. In the drawings:

[0040] Figure 1 FIG. 1 shows a structural diagram of a SiO / C negative electrode gas-phase prelithiation device according to an embodiment of the present application;

[0041] Figure 2 FIG. 2 shows a scanning electron microscope image of a reaction material according to an embodiment of the present application;

[0042] Figure 3 FIG. 3 shows a first charge-discharge curve of a lithium battery according to an embodiment of the present application; and

[0043] Figure 4 FIG. 4 shows a flowchart of a SiO / C negative electrode gas-phase prelithiation method according to an embodiment of the present application.

[0044] In the drawings, the following reference signs are used:

[0045] 1, first gas pipe; 2, second gas pipe; 3, lithium source box; 4, reaction container; 5, discharge port; 6, rotary drive device; 7, sealing door; 8, turnover plate. DETAILED DESCRIPTION

[0046] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0047] For reference Figures 1 to 3As shown, the present application provides a SiO / C negative electrode gas phase pre-lithium device, comprising: a reaction container 4 having a reaction cavity for containing SiO / C; a lithium source box 3 arranged in the reaction cavity, having a containing cavity configured to contain a lithium source and a gas outlet communicating with the containing cavity; a first gas pipe 1 communicating with the reaction cavity; a second gas pipe 2 communicating with the lithium source box 3 and configured to introduce protective gas into the containing cavity; and a heater configured to heat the reaction cavity.

[0048] The SiO / C negative electrode gas phase pre-lithium device can use the first gas pipe 1 to replace the gas environment in the reaction cavity, use the heater to melt the lithium source, and then use the second gas pipe 2 to blow the lithium source into the reaction cavity in a gaseous state to react with SiO / C, realizing gas phase pre-lithium of SiO / C. After the lithium source becomes a gas state, the concentration is low, and the reaction with SiO / C is relatively mild, which can effectively inhibit the growth of grain size and improve the performance of the sample, thereby effectively improving the initial efficiency, and does not involve organic solvents, is environmentally friendly, has small post-processing difficulty, and is green and environmentally friendly.

[0049] In the present embodiment, two gas pipes are used to supply protective gas to the reaction cavity, wherein the first gas pipe 1 can introduce protective gas or carbon source gas, and can also provide a mixture of protective gas and carbon source gas, thereby providing an oxygen-free atmosphere for the reaction of lithium source vapor and SiO / C. In addition, the flow of the first gas pipe 1 can be used to strengthen the sweeping of lithium source vapor generated in the lithium source box 3, so that the lithium source vapor can be more easily diffused in the reaction cavity, improving the reaction efficiency of the lithium source vapor and SiO / C. In order to further improve the blowing effect of the first gas pipe 1 on the lithium source vapor, the outlet of the first gas pipe 1 can be arranged corresponding to the outlet of the lithium source vapor.

[0050] The purpose of the second gas pipe 2 introducing protective gas into the lithium source box 3 is to blow gas into the lithium source box 3, thereby helping the lithium source in a molten state to form lithium source vapor, improving the gasification efficiency of the lithium source and helping the diffusion of the lithium source vapor, facilitating the rapid distribution of the lithium source vapor to the entire reaction cavity, and accelerating the reaction efficiency of the lithium source vapor and SiO / C.

[0051] In one embodiment, the SiO / C negative electrode gas phase pre-lithium device further comprises a rotary drive device 6 drivingly connected with the reaction container 4 to drive the reaction container 4 to rotate. In the present embodiment, the rotary drive device 6 can be conveniently arranged in a rotary driving relationship with the reaction container 4, so as to realize the overturning of the reaction container 4 by the rotary drive device 6, so that the SiO / C in the reaction container 4 forms a tumbling state, thereby enhancing the reaction efficiency of the lithium source vapor and SiO / C and making the reaction of the lithium source vapor and SiO / C more sufficient.

[0052] In one embodiment, the rotating driving device 6 can include a motor, and a driving gear can be arranged at the output end of the motor. The reaction container 4 is in a cylindrical structure, and a driven gear is arranged at the outer periphery of the reaction container 4. The driven gear is engaged with the driving gear and can rotate under the driving of the driving gear, thereby driving the reaction container 4 to rotate.

[0053] In one embodiment, the rotating driving device 6 can include a motor, and a driving gear can be arranged at the output end of the motor. The reaction container 4 is in a cylindrical structure, and a driven gear is arranged at the outer periphery of the reaction container 4. The driven gear is engaged with the driving gear and can rotate under the driving of the driving gear, thereby driving the reaction container 4 to rotate.

[0054] The rotating structure of the reaction container 4 can be realized by adding an auxiliary support structure. For example, a support frame can be arranged, and an outer sleeve ring is arranged on the support frame. An inner sleeve ring is arranged at the outer periphery of the reaction container 4, and the outer sleeve ring is sleeved outside the inner sleeve ring. A plurality of rolling balls are arranged between the outer sleeve ring and the inner sleeve ring. The reaction container 4 can rotate relative to the support frame through the cooperation of the inner sleeve ring and the outer sleeve ring, and is supported on the support frame by the outer sleeve ring.

[0055] The rotating support structure of the reaction container 4 is arranged at the outer periphery of the reaction container 4, which can avoid affecting the reaction in the reaction container 4 and affecting the internal space of the reaction container 4, so as to ensure that the reaction cavity of the reaction container 4 has a good reaction environment and improve the reaction efficiency.

[0056] In one embodiment, the reaction container 4 can also be installed and arranged by arranging a support rotating shaft in the reaction container 4.

[0057] In one embodiment, the inner side wall of the reaction container 4 is provided with a turnover plate 8, and the turnover plate 8 protrudes from the inner side wall to the center of the reaction container 4.

[0058] In the embodiment, the turnover plate 8 can block the SiO / C in the turnover process, so as to avoid the SiO / C from flowing along the wall when the reaction container 4 rotates. When the accumulation of SiO / C on the turnover plate 8 reaches a certain height and the turnover plate 8 is turned to a certain angle, the accumulated SiO / C falls from a high place and forms a dispersed structure, which can more fully contact the lithium source vapor distributed in the reaction cavity and form a more sufficient reaction, thereby improving the reaction efficiency. The turnover plate 8 can be a thin plate structure and extend along the axial direction of the reaction container 4. A plurality of turnover plates 8 are uniformly and spacedly arranged along the circumferential direction of the reaction container 4, which can further improve the turnover efficiency of the reaction container 4 in the turnover process, thereby improving the reaction efficiency of the lithium source vapor and the SiO / C.

[0059] The height of the turning plate 8 cannot be too high, otherwise the turning space will be small and the SiO / C cannot be fully turned. The height of the turning plate 8 also cannot be too low, otherwise the turning cannot be effectively performed. In the embodiment, the radial height of the turning plate 8 is 1 / 6-1 / 2 of the radius of the reaction container 4.

[0060] In an embodiment, an installation port is formed at the end of the reaction container 4, and the installation port is provided with an installation plug. The installation plug can rotate relative to the reaction container 4, and the first gas pipe 1 and the second gas pipe 2 are both installed on the installation plug.

[0061] In the embodiment, by forming the installation port at the end of the reaction container 4 and providing the installation plug there, the installation plug can be used to install the first gas pipe 1 and the second gas pipe 2. The installation plug can rotate relative to the reaction container 4, so when the reaction container 4 rotates, the installation plug can remain stationary, and the first gas pipe 1 and the second gas pipe 2 can also not rotate with the reaction container 4, so that a stable working state can be achieved and the first gas pipe 1 and the second gas pipe 2 can also not be twisted.

[0062] Since the second gas pipe 2 is connected to the lithium source box 3, the lithium source box 3 also does not rotate during the rotation of the reaction container 4.

[0063] In order to facilitate the installation of the lithium source box 3 and avoid occupying the space in the reaction container 4 by adding additional structures, the lithium source box 3 can be connected to the end of the second gas pipe 2 and installed and fixed through the second gas pipe 2.

[0064] In an embodiment, a sealable door 7 is formed on the reaction container 4 and can be opened or closed. The sealable door 7 is configured to place the lithium source and / or SiO / C into the lithium source box 3. In the embodiment, by providing the sealable door 7 on the reaction container 4, a discharging channel can be formed by opening the sealable door 7. The SiO / C can be discharged into the reaction cavity through the discharging channel at the sealable door 7, and the lithium source can be discharged into the lithium source box 3 through the discharging channel at the sealable door 7, so that the discharging operation can be facilitated.

[0065] The second gas pipe 2 is connected to the bottom of the lithium source box 3, and the top of the lithium source box 3 is provided with a gas outlet. Connecting the second gas pipe 2 to the bottom of the lithium source box 3 and arranging the gas outlet at the top of the lithium source box 3 can increase the flow path of the protective gas of the second gas pipe 2. When the lithium source in the lithium source box 3 is in a molten state, the second gas pipe 2 can ventilate the bottom of the molten lithium source in the lithium source box 3. The gas can make the molten lithium source turn over and more easily form lithium source vapor during the upward movement from the bottom of the lithium source. Moreover, the lithium source vapor can be more easily purged, and the diffusion of the lithium source vapor can be strengthened.

[0066] In one embodiment, the reaction container 4 is provided with a discharge port 5 at the end thereof, and a sealing structure is arranged at the discharge port 5, which can open or close the discharge port 5. The discharge port 5 can be used to discharge tail gas and waste gas during the reaction process, and can also be used to discharge the reaction material after the reaction is completed.

[0067] The protective gas is a gas that does not react with the lithium source and SiO / C, and is generally an inert gas other than nitrogen. In one embodiment, the protective gas is at least one of helium, neon, argon, krypton, xenon and radon.

[0068] The heater includes a heating resistance wire sleeved outside the reaction container 4, and the temperature in the reaction cavity of the reaction container 4 can be conveniently adjusted by controlling the power of the heating resistance wire, so that the reaction temperature can be accurately adjusted. The heating resistance wire is located outside the reaction container 4, so it will not react with the objects in the reaction container 4, and can also avoid directly adversely affecting the materials in the reaction container 4, thereby improving the stability and reliability of the reaction. The maximum reaction temperature in the reaction cavity is not more than 1000℃.

[0069] The SiO / C negative electrode gas phase pre-lithium device has the advantages of simple structure, easy implementation, environmental friendliness, good operability and low cost.

[0070] For a better understanding of the present application, reference will be made by way of example to the accompanying drawings in which: Figure 4 As shown in the drawings, according to the embodiment of the present application, the SiO / C negative electrode gas phase pre-lithium method uses the above-mentioned SiO / C negative electrode gas phase pre-lithium device, which comprises: placing SiO / C into the reaction cavity of the reaction container 4; placing the lithium source into the lithium source box 3; introducing the protective gas into the reaction cavity through the first gas pipe 1 to displace the air in the reaction cavity; heating the reaction cavity to make the temperature in the reaction cavity reach a first preset temperature, wherein the first preset temperature is above the melting point of the lithium source; making the lithium source vapor react with the SiO / C for a preset time to generate a reaction material.

[0071] In this embodiment, when the SiO / C negative electrode is gas phase pre-lithiated, the protective gas is first introduced into the reaction cavity through the first gas pipe 1 to displace the air in the reaction cavity, so that the reaction cavity is filled with the protective gas, thereby the reaction environment in the reaction cavity can be treated to make the environment in the reaction cavity be an oxygen-free atmosphere. In this process, the reaction container 4 is not heated, so the temperature in the reaction cavity is at room temperature, and the lithium source is stable and will not react with the air in the reaction cavity.

[0072] After the oxygen-free atmosphere is entered into the reaction cavity, the lithium source can be heated at this time, and since the atmosphere in which the lithium source is located is a protective gas, the reaction during the gasification of the lithium source can be avoided, thereby ensuring the stability of the lithium source. During the process in which the lithium source reaches the melting point and is gasified, the protective gas in the first gas pipe 1 is continuously introduced into the reaction cavity, and the lithium source vapor can be purged by the protective gas in the first gas pipe 1, so that the lithium source vapor can diffuse in the reaction cavity and then react with the SiO / C located in the reaction cavity to perform gas-phase pre-lithiation on the SiO / C.

[0073] After the lithium source vapor reacts with the SiO / C for a preset time, it can be considered that the lithium source vapor has fully reacted with the SiO / C, and at this time, subsequent processing processes can be performed, such as natural cooling or carbon source gas coating.

[0074] In an embodiment, after the step of the temperature in the reaction cavity reaching the first preset temperature, and before the step of the lithium source vapor reacting with the SiO / C for a preset time, the SiO / C negative electrode gas-phase pre-lithiation method further includes: introducing the protective gas into the lithium source box 3 by the second gas pipe 2, and blowing the lithium source vapor into the reaction cavity.

[0075] In this embodiment, by introducing the protective gas into the lithium source box 3 through the second gas pipe 2, the molten lithium source can be more easily gasified, and then the lithium source vapor can be more rapidly diffused in the reaction cavity by the protective gas of the second gas pipe 2, thereby improving the reaction efficiency.

[0076] During the process in which the protective gas is introduced into the lithium source box 3 by the second gas pipe 2, the evaporation amount of the lithium source can be controlled by changing the gas introduction time and the gas introduction amount of the second gas pipe 2, thereby controlling the molar ratio of the lithium source vapor reacting with the SiO / C, so that the molar ratio of the lithium source vapor reacting with the SiO / C is optimized, and the reaction efficiency is improved.

[0077] In an embodiment, the SiO / C negative electrode gas-phase pre-lithiation method further includes: after the lithium source vapor reacts with the SiO / C, cooling the reaction cavity and closing the second gas pipe 2; when the temperature in the reaction cavity decreases to a preset temperature, closing the first gas pipe 1; and discharging the reaction material from the discharge port 5.

[0078] In the embodiment, after the lithium source vapor reacts with the SiO / C, the second gas pipe 2 can be closed because the lithium source vapor does not need to be diffused into the reaction cavity. At the same time, the lithium source or the reaction material needs to be prevented from reacting with air at high temperature, so the first gas pipe 1 is still used to introduce the protective gas into the reaction cavity to maintain the oxygen-free atmosphere. After the temperature in the reaction cavity decreases to the preset temperature, the lithium source and the reaction material in the reaction cavity will not react with air, so the first gas pipe 1 can be closed and the protective gas is no longer introduced into the reaction cavity. Then the reaction material can be discharged from the discharge port.

[0079] In one embodiment, the SiO / C negative electrode gas-phase pre-lithiation method further comprises: after the lithium source vapor reacts with the SiO / C, the temperature of the reaction cavity is increased to a second preset temperature, wherein the second preset temperature is greater than the first preset temperature; the gas source of the first gas pipe 1 is switched, the mixed gas of the protective gas and the carbon source gas is introduced into the reaction cavity through the first gas pipe 1, and the temperature is maintained for a preset time; the gas source of the first gas pipe 1 is switched, the protective gas is introduced into the reaction cavity through the first gas pipe 1; when the temperature in the reaction cavity decreases to the preset temperature, the first gas pipe 1 is closed; and the reaction material is discharged from the discharge port 5.

[0080] In the embodiment, after the lithium source vapor reacts with the SiO / C, the reaction cavity is continuously heated, and the carbon source gas is introduced into the reaction cavity, so that the pre-lithiation reaction and the carbon layer coating repair process can be completed in the same reaction kettle, without repeated temperature rising and falling, which can save energy consumption and better control the grain size.

[0081] In one embodiment, the preset time for the lithium source vapor to react with the SiO / C is 2h-15h, and the temperature for maintaining the temperature is 400°C-1000°C.

[0082] In one embodiment, the lithium source is at least one of metallic lithium, lithium oxide, lithium carbonate, lithium hydroxide, lithium acetate, lithium azide, and butyl lithium.

[0083] In one embodiment, the material of the reaction container 4 is a high-temperature corrosion-resistant material, for example, high-purity corundum, 316 stainless steel, titanium material, etc.

[0084] In one embodiment, the carbon source gas is at least one of acetylene, methane, and toluene.

[0085] Comparative Example

[0086] 5kg of SiO / C and 0.4kg of lithium powder are mixed in a ball mill under argon protection for 5h, and the material is taken out and placed in a box furnace for calcination under argon protection for 5h. The calcination temperature is 650°C. After discharging, the material is broken and de-agglomerated, and sieved through a 200 mesh screen.

[0087] Example 1

[0088] The reaction container 4 is filled with 5 kg of SiO / C, argon is introduced as a protective gas, and after the air in the reaction cavity of the reaction container 4 is completely replaced, 0.4 kg of lithium metal is added to the lithium source box 3, the temperature is raised to 650 DEG C, argon is introduced into the second gas pipe 2 connected to the lithium source box 3, the flow rate is 100 L / h, the reaction is carried out for 5 h, and then the material is naturally cooled and discharged. After the discharge, the material is broken and the agglomeration is removed, and the material is passed through a 200-mesh sieve.

[0089] Example 2

[0090] The reaction container 4 is filled with 5 kg of SiO / C, argon is introduced as a protective gas, and after the air in the reaction cavity of the reaction container 4 is completely replaced, 0.4 kg of lithium metal is added to the lithium source box 3, the temperature is raised to 650 DEG C, argon is introduced into the second gas pipe 2 connected to the lithium source box 3, the flow rate is 100 L / h, the reaction is carried out for 5 h, and then the material is naturally cooled and discharged. After the discharge, the material is broken and the agglomeration is removed, and the material is passed through a 200-mesh sieve.

[0091] Table 1 Comparison of electrical properties of the inventive examples 1 and 2 and the comparative examples

[0092] Sample 0.8V first cycle reversible capacity 0.8V first cycle coulombic efficiency Resistivity Ωcm Grain size nm Example 1 120 1.1 mAh / g 79.5％ 1.33 10.9 Example 2 123 9.6 mAh / g 80.2％ 0.95 11.3 Comparative Example 111 15.2 mAh / g 78.5％ 2.02 17.5

[0093] As can be seen from Table 1, compared with the comparative examples, the grain size of Example 1 is significantly reduced, from 17.5 nm to 10.9 nm, a decrease of 37.7%, the first circle reversible capacity at 0.8 V is increased from 1115.2 mAh / g to 1201.1 mAh / g, an increase of 7.7%, the first circle coulombic efficiency at 0.8 V is increased from 78.5% to 79.5%, the resistivity is reduced from 2.02 Ωcm to 1.33 Ωcm, a decrease of 34.2%, and the electrical properties are obviously improved.

[0094] Compared with the comparative examples, the grain size of Example 2 is significantly reduced, from 17.5 nm to 11.3 nm, a decrease of 35.4%, the first circle reversible capacity at 0.8 V is increased from 1115.2 mAh / g to 1239.6 mAh / g, an increase of 11.2%, the first circle coulombic efficiency at 0.8 V is increased from 78.5% to 80.2%, the resistivity is reduced from 2.02 Ωcm to 0.95 Ωcm, a decrease of 53.0%, and the electrical properties are obviously improved.

[0095] Compared with Example 1, Example 2 increases the post-processing process of gas phase coating, and after secondary sintering, the grain size does not increase obviously, the capacity and initial efficiency are slightly improved, compared with the uncoated Example 1, the capacity is increased from 1201.1 mAh / g to 1239.6 mAh / g, and the initial efficiency is increased from 79.5% to 80.2%, the reason is that after coating, the resistivity is reduced, the material polarization is small, and the electrical performance is improved.

[0096] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments in accordance with the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, steps, operations, devices, components and / or combinations thereof, but do not preclude the presence or addition of one or more other features, steps, operations, devices, components and / or combinations thereof.

[0097] It should be noted that the terms "first", "second", and the like, as used in the specification and in the claims, are intended to modify a particular aspect of the subject matter described in the specification and claims, but do not specifically limit the order or sequence of steps of the method processes unless explicitly stated to do so. It will be understood by those within the art that the order of steps in the foregoing disclosed processes can be modified without departing from the spirit of the application.

[0098] The preferred embodiments of the application are described above with the specific embodiments. The application is not limited to the above examples, and various modifications and changes can be made by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the application shall be included in the protection scope of the application.

Claims

1. A SiO / C negative electrode gas-phase prelithiation device, characterized by, The SiO / C negative electrode gas phase prelithiation device comprises: a reaction container (4) having a reaction cavity for containing SiO / C; a lithium source box (3) arranged in the reaction cavity, having a containing cavity configured to contain a lithium source and a gas outlet communicating with the containing cavity; a first gas pipe (1) communicating with the reaction cavity; a second gas pipe (2) communicating with the lithium source box (3) and configured to introduce a protective gas into the containing cavity; the second gas pipe (2) communicates with the bottom of the lithium source box (3), and the top of the lithium source box (3) is provided with a gas outlet; a heater configured to heat the reaction cavity; an end of the reaction container (4) is provided with a mounting port, and the mounting port is provided with a mounting plug which can rotate relative to the reaction container (4), and the first gas pipe (1) and the second gas pipe (2) are mounted on the mounting plug; the first gas pipe (1) and the second gas pipe (2) do not rotate with the reaction container (4), and the lithium source box (3) also does not rotate.

2. The SiO / C anode vapor pre-lithiation device of claim 1, wherein, The SiO / C negative electrode gas phase prelithiation device further comprises a rotary driving device (6) drivingly connected with the reaction container (4) to drive the reaction container (4) to rotate.

3. The SiO / C anode vapor pre-lithiation device of claim 2, wherein, A turnover plate (8) is arranged on the inner side wall of the reaction container (4) and protrudes from the inner side wall to the center of the reaction container (4).

4. The SiO / C anode vapor pre-lithiation device of claim 1, wherein, A sealable door (7) is arranged on the reaction container (4) and can be opened or closed, and the sealable door (7) is configured to place a lithium source and / or SiO / C into the lithium source box (3).

5. The SiO / C anode vapor pre-lithiation device of claim 1, wherein, An outlet (5) is arranged at the end of the reaction container (4), and a blocking structure is arranged at the outlet (5) and can open or close the outlet (5); and / or the protective gas is at least one of helium, neon, argon, krypton, xenon and radon.

6. A SiO / C anode gas-phase prelithiation method using the SiO / C anode gas-phase prelithiation device according to any one of claims 1 to 5, characterized by, The SiO / C negative electrode gas phase prelithiation device comprises: placing SiO / C into the reaction cavity of the reaction container (4); placing a lithium source into the lithium source box (3); introducing a protective gas into the reaction cavity through the first gas pipe (1) to replace the air in the reaction cavity; heating the reaction cavity to make the temperature in the reaction cavity reach a first preset temperature, wherein the first preset temperature is above the melting point of the lithium source; making the lithium source vapor react with the SiO / C for a preset time to generate a reaction material.

7. The SiO / C anode vapor prelithiation method of claim 6, wherein, After the step of making the temperature in the reaction cavity reach the first preset temperature and before the step of making the lithium source vapor react with the SiO / C for a preset time, the SiO / C negative electrode gas phase prelithiation method further comprises: introducing a protective gas into the lithium source box (3) through the second gas pipe (2) to blow the lithium source vapor into the reaction cavity.

8. The SiO / C anode vapor prelithiation method of claim 7, wherein, The SiO / C negative electrode gas phase prelithiation method further comprises: after the lithium source vapor reacts with the SiO / C, cooling the reaction cavity and closing the second gas pipe (2); when the temperature in the reaction cavity drops to a preset temperature, closing the first gas pipe (1); discharging the reaction material from the outlet (5).

9. The SiO / C anode vapor prelithiation method of claim 6, wherein, The SiO / C negative electrode gas phase prelithiation method further comprises: After the reaction between the lithium source vapor and the SiO / C is completed, the temperature of the reaction cavity is increased to a second preset temperature, wherein the second preset temperature is greater than the first preset temperature; The gas source of the first gas pipe (1) is switched, and a mixed gas of the protective gas and the carbon source gas is introduced into the reaction cavity through the first gas pipe (1) and is kept at a preset temperature for a preset time; The gas source of the first gas pipe (1) is switched, and the protective gas is introduced into the reaction cavity through the first gas pipe (1); When the temperature in the reaction cavity decreases to a preset temperature, the first gas pipe (1) is closed; The reaction material is discharged from the discharge port (5).

10. The SiO / C anode vapor prelithiation method of claim 6, wherein, The preset time for the reaction between the lithium source vapor and the SiO / C is 2h-15h, and the holding temperature is 400℃-1000℃.

11. The SiO / C anode vapor prelithiation method of claim 6, wherein, The lithium source is at least one of metal lithium, lithium oxide, lithium carbonate, lithium hydroxide, lithium acetate, lithium azide and butyl lithium; and / or the material of the reaction container (4) is a high-temperature corrosion-resistant material.

12. The SiO / C anode vapor prelithiation method of claim 8, wherein, The carbon source gas is at least one of acetylene, methane and toluene.

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