Device and method for preparing SiO composite material

Abstract

The invention provides a preparation method and device of a novel SiO composite material, and belongs to the field of lithium ion battery negative electrode materials, and the preparation method specifically comprises the following steps: S1, respectively putting a graphite / SiO2 mixture and a porous carbon skeleton material into the middle parts of furnace tubes of a first tube furnace and a second tube furnace; s2, air in the device is replaced through high-purity argon and a two-stage rotary vane vacuum pump, and vacuumizing is conducted; s3, a first rotary tube furnace heating program is set, the device is continuously vacuumized, and the two tube furnace tubes keep rotating; s4, after the heating program of the first rotary tube furnace is finished, a heating program of a second rotary tube furnace is set, and high-purity acetylene is introduced into the device; (S5); and after the heating procedure is finished, closing acetylene gas flow, and after the device is cooled, taking out a product in the second rotary tube furnace to obtain the porous carbon / SiO / carbon composite silicon monoxide composite material which can be used as a high-performance lithium ion battery negative electrode material precursor. The method and the device can be used for solving the problems of preparation, purification and compounding operation of SiO in one step, are convenient to use, simple to operate, low in cost and low in risk, and are easy to use in related research and development experiments of the precursor of the SiO negative electrode composite material of the lithium ion battery.

Description

Technical Field

[0001] This invention patent relates to the field of purification and preparation of silicon-based anode materials for lithium-ion batteries, especially to the purification and compounding fields of SiO. Background Art

[0002] Lithium-ion batteries are widely used in consumer products such as mobile phones and laptops, as well as in fields such as electric vehicles. Currently, the main anode material for lithium-ion batteries is graphite, whose actual specific capacity has approached the theoretical specific capacity of 372 mAh / g. The theoretical specific capacity of SiO reaches 2600 mAh / g, and it has a smaller expansion effect compared to the same silicon-based anode, elemental silicon. It has a broader application prospect in the field of lithium-ion battery anode materials.

[0003] Currently, the traditional devices for preparing SiO are relatively complex. And since SiO needs to be compounded with conductive materials such as graphite when applied to anode materials, it involves many steps and the process is rather cumbersome. There is an urgent need to find a reasonable process route and device that can solve this problem through one-step operation. Summary of the Invention

[0004] The technical problem to be solved by this invention patent is to provide a preparation method and device for a new type of SiO composite material. This device greatly simplifies the preparation, purification, and compounding processes of SiO, has simple operation, is a closed operation throughout the process, reduces the danger during experiments, and can be widely applied to the fields of SiO preparation, purification, and compounding.

[0005] The technical solution adopted by this invention patent to solve the above-mentioned existing technical problems is as follows:

[0006] A device for preparing SiO composite material, which includes two rotary tube furnaces. The outer shell material of the rotary tube furnace is cold-rolled steel plate, filled with quartz fiber thermal insulation material inside, and the furnace tube material is high-purity corundum, which can rotate and the rotation speed can be adjusted.

[0007] The outer shell material of the first rotary tube furnace is cold-rolled steel plate, the gap between the outer shell and the furnace tube is filled with quartz fiber thermal insulation material, a cylindrical corundum tube plug 1 is arranged inside the furnace tube, a hole is drilled in the middle of the circular side of the cylindrical tube plug, and a temperature sensor 1 is arranged beside the furnace tube.

[0008] The outer shell material of the second rotary tube furnace is cold-rolled steel plate, the gap between the outer shell and the furnace tube is filled with quartz fiber thermal insulation material, the furnace tube material inside the furnace is high-purity corundum, a cylindrical corundum tube plug 2 is arranged inside the furnace tube, a hole is drilled in the middle of the circular side of the cylindrical tube plug, and a temperature sensor 2 is arranged beside the furnace tube.

[0009] Two rotary tube furnaces are connected by a magnetohydrodynamic joint. A tee is provided in the middle of the pipeline, which is connected to a high-purity acetylene system. The high-purity acetylene system is composed of high-purity acetylene, a stainless-steel pressure reducing valve, a rotameter, and a stainless-steel regulating valve connected by a clean stainless-steel pipeline. The magnetohydrodynamic seal joint can ensure the pipeline seal under the condition of rotation.

[0010] The front end of the first rotary tube furnace is connected to a high-purity argon gas system. The high-purity argon gas system is composed of a high-purity argon gas pipeline, a stainless-steel pressure reducing valve I, a rotameter, and a stainless-steel regulating valve II connected by a clean stainless-steel pipeline, and is used for evacuating and replacing air and purging the device.

[0011] The rear end of the second rotary tube furnace is connected to a pressure sensor and a stainless-steel filter. The stainless-steel filter is connected to a two-stage rotary vane vacuum pump, and a stainless-steel regulating valve V is provided at the rear. The type of the vacuum pump is a two-stage rotary vane vacuum pump.

[0012] In a preferred embodiment, the core materials of the components of the argon gas system are all SUS304, and the purity of the high-purity argon gas is 99.9999%.

[0013] In a preferred embodiment, the long-term operating temperature of the first rotary tube furnace and the second rotary tube furnace is 1200 - 1500 °C. The outer shell material of the tube furnace is cold-rolled steel plate, filled with quartz fiber thermal insulation material inside. The material of the furnace tube is 99% high-purity corundum, with a length of 1000 mm, the length of the heating area is 400 mm. Corundum tube plugs are placed on both sides of the heating area. The inner diameter of the furnace tube is 800 mm, and the material of the corundum tube plug is also 99% high-purity corundum. The furnace tube can rotate by itself during heating.

[0014] In a preferred embodiment, including the magnetohydrodynamic connection joint, its material is SUS304, which can rotate below 500 °C and maintain good sealing performance.

[0015] In a preferred embodiment, including the filter, its material is SUS304, its outer shell material is SUS304, and the internal filter element material is high-purity PTFE material, which can filter 99% of solid particles with a diameter of more than 10 μm.

[0016] In a preferred embodiment, the vacuum pump is a two-stage rotary vane vacuum pump, its pumping speed is greater than 3 L / S, the ultimate pressure is below 10 Pa, and it can continuously work for more than 100 h.

[0017] The present invention also provides a method for preparing a SiO composite material, using the described device, including the following steps:

[0018] (1) Place a certain amount of C / SiO2 mixed powder material in the middle of the furnace tube of the first rotary tube furnace, and place a certain amount of porous carbon skeleton material in the middle of the furnace tube of the second rotary tube furnace. Use high-purity argon and a two-stage rotary vane vacuum pump to displace the air in the device. After the displacement is completed, keep the vacuum pump running continuously to evacuate the air.

[0019] (2) Turn on the heating system and the furnace tube rotation system of the first rotary tube furnace to raise the temperature to the reaction temperature required for preparing SiO. Start the rotation of the furnace tube of the second rotary tube furnace. The SiO generated by the reaction in the first rotary tube furnace sublimes at high temperature and is pumped by the vacuum pump into the furnace tube of the second rotary tube furnace, where it cools and deposits in the pores of the porous carbon skeleton. The furnace tube of the first rotary tube furnace rotates continuously, driving the C / SiO2 mixed powder material inside to tumble, making their contact closer and more intimate. The furnace tube of the second rotary tube furnace rotates continuously, driving the porous carbon inside to tumble, making the deposition of SiO more uniform.

[0020] (3) After reacting for 20 - 30 h, stop heating the first rotary tube furnace, end the reaction in the first rotary tube furnace, and turn off the two-stage rotary vane vacuum pump.

[0021] (4) Turn on the heating of the second rotary tube furnace, control the temperature within the temperature range of acetylene cracking, and introduce high-purity acetylene. Let the high-purity acetylene flow into the second rotary tube furnace. The carbon generated by the cracking of high-purity acetylene at high temperature deposits and coats the surface of the porous carbon material. The furnace tube rotates continuously, driving the porous carbon material inside to tumble, making the deposited carbon more uniform. After 4 - 6 h, end the reaction, stop heating and gas supply. After cooling, open the second rotary tube furnace to take out the porous carbon material, and then the porous carbon / SiO / carbon composite silicon suboxide composite material is obtained.

[0022] The temperature inside the first rotary tube furnace is 1200℃ - 1400℃, and the pressure is less than 10 Pa.

[0023] The temperature inside the second rotary tube furnace is 800℃ - 1000℃.

[0024] The rotation speed of the first rotary tube furnace is 3 - 5 rpm; the rotation speed of the second rotary tube furnace is 10 - 20 rpm.

[0025] A preparation method and device for a novel SiO composite material provided by the present invention for invention patent. The furnace tube of the first rotary tube furnace rotates continuously during heating, enabling sufficient contact between materials, increasing the reaction rate, reducing the agglomeration of materials during sintering, and greatly improving the escape rate of silicon monoxide. By setting an argon system, argon is introduced at the front of the first rotary tube furnace, and a vacuum pump is set at the rear to evacuate the air. The argon carries out SiO vapor. The furnace tube of the second rotary tube furnace keeps rotating, enabling uniform deposition of SiO in the porous carbon framework. After the reaction ends, the second rotary tube furnace is heated, and acetylene gas is introduced. The carbon generated by cracking is deposited and coated on the surface of the porous carbon framework, and a high-performance negative electrode material of porous carbon / SiO / carbon composite can be obtained. This device can be widely used in the gas-phase deposition experiment of silicon-based negative electrodes, can solve the preparation, purification, and composite operations of SiO in one go, is simple to operate, has strong R & D attributes, the prepared SiO composite material has high purity, good product uniformity, and low production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The following further describes the present invention for invention patent with reference to the drawings and embodiments:

[0027] Figure 1 It is a schematic diagram of the overall structure of the device related to the present invention for invention patent;

[0028] In the figure: 1-high-purity argon; 2-stainless steel pressure reducing valve; 3-rotameter; 4-stainless steel regulating valve; 5-first rotary tube furnace; 6-corundum tube plug; 7-temperature sensor; 8-high-purity acetylene; 9-stainless steel regulating valve; 10-rotameter; 11-stainless steel regulating valve; 12-magnetic fluid sealing joint; 13-second rotary tube furnace; 14-corundum tube plug; 15-temperature sensor; 16-pressure sensor; 17-stainless steel filter; 18-two-stage rotary vane vacuum pump; 19-stainless steel regulating valve. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] To further understand the content, features, and effects of the present invention for invention patent, the following examples are cited and described in detail with the accompanying drawings:

[0030] Please refer to Figure 1 , a device for preparing SiO composite material. This device includes a first rotary tube furnace 5 and a second rotary tube furnace 13. The first rotary tube furnace 5 and the second rotary tube furnace 13 are connected through a magnetic fluid sealing joint 12, and a three-way valve is arranged in the middle of the connecting pipeline;

[0031] The three-way valve is connected to a high-purity acetylene system. In the high-purity acetylene system, high-purity acetylene 8, stainless steel pressure reducing valve three 9, rotameter 10, and stainless steel regulating valve four 11 are connected through a clean stainless steel pipeline.

[0032] The housing material of the first rotary tube furnace 5 is cold-rolled steel plate. The space between the housing and the furnace tube is filled with quartz fiber insulation material. The material of the furnace tube of the tube furnace is high-purity corundum. A cylindrical corundum tube plug 6 is arranged in the furnace tube. A hole is drilled in the middle of the circular side of the cylindrical tube plug. A temperature sensor 7 is arranged beside the furnace tube.

[0033] The housing material of the second rotary tube furnace 13 is cold-rolled steel plate. The space between the housing and the furnace tube is filled with quartz fiber insulation material. The material of the furnace tube in the furnace is high-purity corundum. A cylindrical corundum tube plug 14 is arranged in the furnace tube. A hole is drilled in the middle of the circular side of the cylindrical tube plug. A temperature sensor 15 is arranged beside the furnace tube.

[0034] The front end of the first rotary tube furnace 5 is connected to a high-purity argon gas system. The high-purity argon gas system is composed of high-purity argon 1, a stainless steel pressure reducing valve 1, a rotameter 3, and a stainless steel regulating valve 2 connected by a clean stainless steel pipeline, and is used for evacuating and replacing air and purging the device.

[0035] The rear end of the second rotary tube furnace 13 is connected to a pressure sensor 16 and a stainless steel filter 17. The stainless steel filter 17 is connected to a two-stage rotary vane vacuum pump 18, and a stainless steel regulating valve 5 is arranged at the rear. The type of the vacuum pump is a two-stage rotary vane vacuum pump.

[0036] Example 2

[0037] The device of Example 1 is used for the preparation of SiO composite materials, and the steps are as follows:

[0038] (1) Placing materials: Place 360 g of C / SiO2 (molar ratio 1:1) mixed powder materials in the middle of the furnace tube of the first rotary tube furnace 5, and place 200 g of porous carbon skeleton materials in the middle of the furnace tube of the second rotary tube furnace 13. Cylindrical tube plugs with holes in the middle are placed on both sides of the materials in the furnace tube to restrict the materials. The two rotary tube furnaces are connected by a magnetohydrodynamic sealing joint. The air in the device is replaced by high-purity argon and a two-stage rotary vane vacuum pump. After the replacement is completed, the vacuum pump is kept running continuously to evacuate.

[0039] (2) Starting the reaction and deposition: Turn on the heating system of the first rotary tube furnace 5, set the rotation speed of the furnace tube to 5 rpm, and heat it up to 1400 °C to prepare SiO. Start the rotation of the furnace tube of the second rotary tube furnace 13, with a rotation speed of 10 rpm. The SiO generated by the reaction in the first rotary tube furnace 5 sublimes at high temperature and is pumped by the vacuum pump into the furnace tube of the second rotary tube furnace 13 to cool and deposit in the pores of the porous carbon skeleton. The continuous rotation of the furnace tube drives the porous carbon inside to tumble, making the deposition of SiO more uniform. The un-deposited SiO powder is filtered by the stainless steel filter 17 to prevent it from entering the two-stage rotary vane vacuum pump 18.

[0040] (3) Stop reaction deposition: After heating the first rotary tube furnace 5 for 30 h, stop heating, end the reaction of the first rotary tube furnace 5, and close the two-stage rotary vane vacuum pump 18.

[0041] (4) Start pyrolysis deposition: Turn on the second rotary tube furnace 13 for heating, raise the temperature to 1000 °C, introduce high-purity acetylene, and control the acetylene flow rate to be 2 L / min through the rotameter 10, so that the high-purity acetylene is uniformly introduced into the second rotary tube furnace 13. The carbon deposited by the pyrolysis of high-purity acetylene at high temperature is coated on the surface of the porous carbon material. The furnace tube rotates continuously to drive the porous carbon material inside to tumble, making the deposited carbon more uniform.

[0042] (5) Stop pyrolysis deposition: After 4 h, end the reaction, stop heating and gas supply. After the furnace tube cools down, open the second rotary tube furnace (13) to take out the porous carbon material, and the porous carbon / SiO / carbon composite silicon suboxide composite material is obtained.

[0043] Example 3

[0044] The method for preparing the porous carbon / SiO / carbon composite silicon suboxide composite material described in this example is the same as that in Example 2, except that the heating temperature of the first rotary tube furnace 5 described in this example is 1300 °C, and the heating temperature of the second rotary tube furnace (13) is 900 °C.

[0045] Example 4

[0046] The method for preparing the porous carbon / SiO / carbon composite silicon suboxide composite material described in this example is the same as that in Example 2, except that the heating temperature of the first rotary tube furnace 5 described in this example is 1200 °C, and the heating temperature of the second rotary tube furnace 13 is 800 °C.

[0047] Example 5

[0048] The method for preparing the porous carbon / SiO / carbon composite silicon suboxide composite material described in this example is the same as that in Example 2, except that the rotation speed of the first rotary tube furnace 5 described in this example is 5 rpm, and the rotation speed of the second rotary tube furnace 13 is 20 rpm.

[0049] Comparative Example 1

[0050] The method for preparing the porous carbon / SiO / carbon composite silicon suboxide composite material described in this example is the same as that in Example 2, except that the heating temperature of the first rotary tube furnace 5 described in this example is 1100 °C.

[0051] Comparative Example 2

[0052] The method for preparing the porous carbon / SiO / carbon composite silicon monoxide composite material in this example is the same as that in Example 2, except that the heating temperature of the second rotary tube furnace 13 in this example is 700 °C.

[0053] Comparative Example 3

[0054] The method for preparing the porous carbon / SiO / carbon composite silicon monoxide composite material in this example is the same as that in Example 2, except that the rotation speed of the first rotary tube furnace 5 in this example is 10 rpm and the rotation speed of the second rotary tube furnace 13 is 20 rpm.

[0055] Comparative Example 4

[0056] The device of Example 1 was used to prepare the SiO composite material, and the steps were as follows:

[0057] (1) Placing the materials: 360 g of C / SiO2 (molar ratio 1:1) mixed powder materials were placed in the middle of the furnace tube of the first rotary tube furnace 5. Cylindrical tube plugs with middle openings were placed on both sides of the materials in the furnace tube to restrict the materials. The two rotary tube furnaces were connected by a magnetohydrodynamic sealing joint. High-purity argon and a two-stage rotary vane vacuum pump were used to displace the air in the device. After the displacement was completed, the vacuum pump continued to operate under vacuum.

[0058] (2) Starting the reaction deposition: The heating system of the first rotary tube furnace 5 was turned on, the rotation speed of the furnace tube was set to 5 rpm, and it was heated to 1400 °C to prepare SiO. The rotation of the furnace tube of the second rotary tube furnace 13 was started, with a rotation speed of 10 rpm. The SiO generated by the reaction in the first rotary tube furnace 5 sublimated at high temperature and was pumped into the furnace tube of the second rotary tube furnace 13 by the vacuum pump for cooling treatment.

[0059] (3) Stopping the reaction deposition: After heating the first rotary tube furnace 5 for 30 h, the heating was stopped, the reaction of the first rotary tube furnace 5 was ended, and the two-stage rotary vane vacuum pump 18 was turned off.

[0060] (4) Starting the cracking deposition: The second rotary tube furnace 13 was heated to 1000 °C, and high-purity acetylene was introduced. The flow rate of acetylene was controlled to be 2 L / min by the rotameter 10, so that the high-purity acetylene was uniformly introduced into the second rotary tube furnace 13. The carbon generated by the cracking of the high-purity acetylene at high temperature was deposited and coated on the surface of SiO. The rotation of the furnace tube drove the SiO material inside to tumble, making the deposited carbon more uniform.

[0061] (5) Stopping the cracking deposition: After 4 h, the reaction was ended, the heating and gas supply were stopped. After the furnace tube cooled down, the second rotary tube furnace (13) was opened to take out the porous carbon material, and the SiO / carbon composite silicon monoxide composite material was obtained.

[0062] Comparative Example 5

[0063] The device of Example 1 was used to prepare the SiO composite material, and the steps were as follows:

[0064] (1) Placing materials: 360 g of C / SiO2 (molar ratio 1:1) mixed powder materials were placed in the middle of the furnace tube of the first rotary tube furnace 5, and 200 g of porous carbon skeleton materials were placed in the middle of the furnace tube of the second rotary tube furnace 13. Cylindrical tube plugs with middle openings were placed on both sides of the materials in the furnace tubes to restrain the materials. The two rotary tube furnaces were connected by a magneto - fluid seal joint. High - purity argon and a two - stage rotary vane vacuum pump were used to displace the air in the device. After the displacement was completed, the vacuum pump continued to operate under vacuum;

[0065] (2) Starting the reaction deposition: The heating system of the first rotary tube furnace 5 was turned on, the rotation speed of the furnace tube was set to 5 rpm, and it was heated to 1400 °C to prepare SiO. The rotation of the furnace tube of the second rotary tube furnace 13 was started, with a rotation speed of 10 rpm. The SiO generated by the reaction in the first rotary tube furnace 5 sublimated at high temperature and was pumped by the vacuum pump into the furnace tube of the second rotary tube furnace 13, where it cooled and deposited in the pores of the porous carbon skeleton. The continuous rotation of the furnace tube drove the porous carbon inside to tumble, making the deposition of SiO more uniform. The un - deposited SiO powder was filtered by the stainless - steel filter 17 to prevent it from entering the two - stage rotary vane vacuum pump 18;

[0066] (3) Stopping the reaction deposition: After heating the first rotary tube furnace 5 for 30 h, the heating was stopped, the reaction of the first rotary tube furnace 5 was ended, and the two - stage rotary vane vacuum pump 18 was turned off.

[0067] Open the second rotary tube furnace (13) and take out the porous carbon material to obtain the porous carbon / SiO composite silicon sub - oxide composite material.

[0068] Table 1 Comparison of the effects of examples and comparative examples

[0069]

[0070] Note: The performance tests of the anode materials were all carried out at a current of 200 mA.

[0071] When the temperature of the tube furnace in Examples 2 to 4 decreases, the yield and silicon content will decrease, and the performance of the anode material will also decrease accordingly; as can be seen from Example 5, when the rotation speed of the second rotary tube furnace (13) is too high, the yield will decrease. It is found in the experiment that a lot of materials are carried out of the tube furnace by the gas flow at this time; as can be seen from Comparative Example 1, when the first rotary tube furnace (5) is reduced to 1100 °C, the C / SiO2 reaction rate slows down greatly, and the yield will decrease accordingly; as can be seen from Comparative Example 2, when the temperature of the second rotary tube furnace (13) is reduced to 700 °C, the acetylene cracking rate will slow down, the carbon coating is not complete, and the performance of the anode material decreases; as can be seen from Comparative Examples 4 and 5, when there is no carbon coating or carbon skeleton, the performance of the anode material will decrease to varying degrees. In summary, the method for preparing the SiO composite material provided by the present invention can achieve a good yield of the porous carbon / SiO / carbon composite silicon monoxide composite material under the conditions of Example 2, and the first charge-discharge specific capacity and the first charge-discharge efficiency are both relatively high

[0072] The above description is only a preferred embodiment of the present invention, and does not impose any form of limitation on the present invention. Any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention are all within the scope of the technical solution of the present invention.

Claims

1. A device for preparing SiO composite material, characterized in that: The device comprises a first rotary tube furnace (5), a second rotary tube furnace (13), The first rotary tube furnace (5) and the second rotary tube furnace (13) are connected via a magnetic fluid sealing joint (12), and a three-way valve is provided in the middle of the connected pipeline; The three-way valve is connected to a high-purity acetylene system, in which a high-purity acetylene pipeline (8), a stainless steel pressure reducing valve three (9), a rotor flow meter (10), and a stainless steel regulating valve four (11) are connected through clean stainless steel pipelines.

2. The device for preparing SiO composite material according to claim 1, characterized in that: The shell of the first rotary tube furnace (5) is made of cold-rolled steel plate, the gap between the shell and the furnace tube is filled with quartz fiber insulation material, the furnace tube in the furnace is made of high-purity corundum, a cylindrical corundum tube plug (6) is arranged in the furnace tube, the cylindrical corundum tube plug (6) is inserted into the cylinder of the furnace tube, there is a hole in the middle of the tube plug, and a temperature sensor (7) is arranged next to the furnace tube.

3. The device for preparing SiO composite material according to claim 1, characterized in that: The shell of the second rotary tube furnace (13) is made of cold-rolled steel plate, the gap between the shell and the furnace tube is filled with quartz fiber insulation material, the furnace tube in the furnace is made of high-purity corundum, a cylindrical corundum pipe plug (14) is arranged in the furnace tube, a hole is punched in the middle of the circular side of the cylindrical pipe plug, and a temperature sensor (15) is arranged next to the furnace tube.

4. The device for preparing SiO composite material according to claim 1, characterized in that: The front end of the first rotary tube furnace (5) is connected to a high-purity argon system, which is composed of a high-purity argon pipeline (1), a stainless steel pressure reducing valve (2), a rotor flow meter (3), and a stainless steel regulating valve (4) connected through a clean stainless steel pipeline, and is used for vacuuming, replacing air, and purging the device.

5. The device for preparing SiO composite material according to claim 1, characterized in that: The rear end of the second rotary tube furnace (13) is connected to a pressure sensor (16) and a stainless steel filter (17), the stainless steel filter (17) is connected to a two-stage rotary vane vacuum pump (18), and a stainless steel regulating valve five (19) is arranged at the rear, and the vacuum pump type is a two-stage rotary vane vacuum pump.

6. The device for preparing SiO composite material according to claim 1, characterized in that: The material of the magnetic fluid connection joint is SUS304; the material of the filter element inside the filter is high-purity PTFE material.

7. A method for preparing a SiO composite material, using the device according to any one of claims 1 to 6, characterized in that: The steps include: (1) adding a certain amount of C / SiO2 mixed powder material to the middle of the furnace tube of the first rotary tube furnace (5), adding a certain amount of porous carbon skeleton material to the middle of the furnace tube of the second rotary tube furnace (13), using a double-stage rotary vane vacuum pump (18) and high-purity argon gas (1) to replace the air in the first rotary tube furnace (5) and the second rotary tube furnace (13), and continuously evacuating the air; (2) heating the first rotary tube furnace (5) under a rotating condition, controlling the temperature, reacting to obtain SiO, then starting the second rotary tube furnace (13) to rotate the furnace tube, and the SiO generated by the reaction in the first rotary tube furnace (5) is sublimated at a high temperature and then pumped into the furnace tube of the second rotary tube furnace (13) through a vacuum pump to cool and deposit in the pores of the porous carbon skeleton, and rotating to ensure uniform deposition of SiO; (3) heating the second rotary tube furnace (13) under a rotating condition, controlling the temperature, introducing high-purity acetylene (8), and causing the high-purity acetylene to be cracked at a high temperature to generate carbon deposits that are coated on the surface of the porous carbon material. Heating and ventilation are stopped, and after cooling, a porous carbon / SiO2 / carbon composite silicon oxide composite material is obtained.

8. The method for preparing the SiO composite material according to claim 7, characterized in that: The temperature in the first rotary tube furnace (5) is 1200° C. to 1400° C., and the pressure is less than 10 Pa.

9. The method for preparing the SiO composite material according to claim 7, characterized in that: The temperature in the second rotary tube furnace (13) is 800°C to 1000°C.

10. The method for preparing the SiO composite material according to claim 7, characterized in that: The rotation speed of the first rotary tube furnace (5) is 3-5 rpm; the rotation speed of the second rotary tube furnace (13) is 10-20 rpm.

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