Plasma enhanced silicon-in-carbon device and method thereof

Abstract

The application relates to a plasma-enhanced carbon-coated silicon device and a method thereof in the field of lithium batteries, which comprises a furnace body and an air extraction mechanism, a controller is arranged on the furnace body, a charging chamber, a coating chamber and a discharging chamber are formed in the furnace body through an inserted plate valve, a rotatable conveying belt is arranged in the furnace body, a workpiece placing table for placing workpieces is arranged on the conveying belt, an air inlet mechanism is arranged on the furnace body, a heating mechanism for heating plating film gas is connected to the air inlet mechanism, a porous air distribution electrode plate is connected to the end of the air inlet mechanism extending to the coating chamber, a pneumatic vibration mechanism is arranged in the coating chamber, a pulse mechanism and a bias mechanism are connected to the furnace body, the carbon-coated silicon device and the method thereof can uniformly coat silicon powder, the heating mechanism, the porous air distribution electrode plate, the pneumatic vibration mechanism and the bias mechanism can further improve the uniformity and reliability of coating, and the coating effect and efficiency are further improved.

Description

Technical Field

[0001] The present invention relates to the field of lithium batteries, and in particular to a plasma-enhanced carbon-coated silicon device and a method thereof. Background Art

[0002] With the growing demand for high-capacity and long-range lithium-ion batteries in new energy vehicles, traditional graphite-based lithium-ion batteries are no longer able to meet these requirements. Silicon-based anode materials, due to their higher theoretical specific capacity, are considered ideal for the next generation of high-energy-density lithium-ion batteries. In recent years, research on silicon-based anode materials has focused on effectively regulating volume changes and ensuring the material's electrical conductivity. Research has shown that concepts such as nanostructures, active-inactive composites, and core-shell structures can effectively mitigate the stresses caused by structural changes in silicon-based materials during cycling.

[0003] Therefore, the performance of silicon-based anode materials is being improved through various silicon-based nanostructures and methods, such as nanostructuring, carbon coating, alloying, the use of silicon oxide, and pre-lithiation. Carbon coating is a proven method. On the one hand, carbon coating reduces the probability of direct contact between nano-silicon particles and the electrolyte, stabilizing the interface and preventing silicon expansion and agglomeration. On the other hand, the graphitized carbon coating improves electrical contact between particles and enhances the material's conductivity.

[0004] However, although the existing carbon-coated silicon material has significant advantages in the field of lithium-ion battery negative electrodes, its existing coating device still has some defects. The existing coating device is generally set up relatively simply, which makes it difficult to quickly transport the coating in the existing vacuum chamber, and the existing coating gas has poor distribution uniformity, which affects the coating performance of the coating material, and the existing coating effect is poor, thereby affecting the stability of the lithium battery performance.

[0005] At the same time, scientific research has used carbon black stirring to study the performance of carbon-coated silicon nanoparticles, and has used carbon-containing organic matter, tubular furnaces to heat carbon-containing gases, and mixed graphite powder and silicon powder for ball milling to perform surface coating. However, most of the current methods have problems such as poor surface coating effect, uneven particle coating, particle clustering, and uneven particle size resulting in rapid performance degradation, as well as poor deposition and coating effect of carbon ions, resulting in low carbon coating preparation efficiency. Summary of the Invention

[0006] The purpose of the present invention is to solve the above defects and provide a plasma-enhanced carbon-coated silicon device and method thereof to solve the technical problems in the above background technology that the structure of the existing silicon coating device is relatively simple and it is not easy to carry out uniform coating, and the coating effect of the existing silicon coating method is poor, thereby affecting the coating efficiency and being unfavorable for use.

[0007] The purpose of the present application is achieved by the following means:

[0008] The application discloses a plasma enhanced carbon-coated silicon device, which comprises a furnace body and a pumping mechanism for pumping the inside of the furnace body, and the two ends of the furnace body are respectively provided with a feeding port and a discharging port, and a controller is arranged on the furnace body, a charging chamber, a coating chamber for plasma coating and a discharging chamber are formed in the furnace body by means of a closable plug valve, the pumping mechanism is communicated with the charging chamber, the coating chamber and the discharging chamber and can pump the charging chamber, the coating chamber and the discharging chamber, a rotatable conveying belt is arranged in the furnace body, the conveying end of the conveying belt extends along the charging chamber, the coating chamber and the discharging chamber, and a workpiece placing table is arranged on the conveying belt, an air inlet mechanism for conveying a coating gas to the coating chamber is arranged on the furnace body, a heating mechanism for heating the coating gas is connected to the air inlet mechanism, and a porous gas distribution electrode plate is connected to the end of the air inlet mechanism extending to the coating chamber, and a pneumatic vibration mechanism for driving the workpiece placing table on the conveying belt to vibrate is arranged in the coating chamber.

[0009] A pulse mechanism and a bias mechanism are connected to the furnace body, the output end of the pulse mechanism is connected with the air inlet mechanism and the furnace body, the pulse mechanism is used for ionizing the coating gas conveyed to the coating chamber, and the conveying end of the bias mechanism is connected with the furnace body and the coating chamber, and the bias mechanism is used for depositing the coating gas.

[0010] Further in the above description, the pumping mechanism comprises a molecular pump, a mechanical pump and a plurality of conduits, the mechanical pump is connected with the molecular pump, and the molecular pump is connected with the charging chamber, the coating chamber and the discharging chamber through the conduits.

[0011] Further in the above description, the furnace body is provided with an air pressure monitoring mechanism for monitoring the air pressure in the furnace, the air pressure monitoring mechanism comprises a vacuum gauge and an automatic throttle valve baffle, the air pressure in the furnace body is detected by the vacuum gauge, and the air pressure conveying of the conduits is controlled by the automatic throttle valve baffle controlled by the vacuum gauge.

[0012] Further in the above description, the air inlet mechanism comprises an air inlet pipe, a flow meter and a gas mixing barrel, the flow meter is connected with the input end of the gas mixing barrel in a conductive mode, one end of the air inlet pipe is connected with the output end of the gas mixing barrel in a conductive mode, the other end of the air inlet pipe extends to the inside of the coating chamber and is connected with the porous gas distribution electrode plate, the porous gas distribution electrode plate is provided with air inlet holes and a plurality of air outlet holes communicated with the air inlet holes, and the air inlet pipe is connected with the air inlet holes in a conductive mode.

[0013] Further in the above description, the heating mechanism comprises a heating pipe and a temperature control system, the heating pipe is sleeved with the end of the air inlet pipe extending to the inside of the coating chamber, the end of the heating pipe extends to the inside of the coating chamber, and the heating pipe is electrically connected with the temperature control system.

[0014] Further in the above description, the pneumatic vibration mechanism includes a pneumatic vibrator and a vibration table. The vibration table is installed on the conveyor belt through a support frame, the pneumatic vibrator is installed at the bottom of the furnace body, and the vibrating end of the pneumatic vibrator extends through the furnace body to the coating chamber, so that the vibration table drives the loading platform to be transported into the coating chamber, and the vibration table is vibrated by the pneumatic vibrator.

[0015] Further in the above description, the pulse mechanism includes a high-voltage pulse power supply, the bias mechanism includes a bias power supply, and both the bias power supply and the high-voltage pulse power supply are electrically connected to the controller.

[0016] Further in the above description, the gate valve is installed on the furnace body, and one end of the gate valve extends into the interior of the furnace body. Two gate valves are provided, and the interior of the furnace body is sequentially spaced to form a loading chamber, a coating chamber and a discharging chamber.

[0017] A plasma-enhanced carbon-coated silicon method comprising the following steps:

[0018] Step 1: using a plasma enhanced carbon-coated silicon device for coating;

[0019] Step 2: Feeding: The internal space of the furnace body is divided into a loading chamber, a coating chamber, and a discharging chamber by lowering and closing the gate valve. Silicon powder is introduced into the loading platform in the loading chamber through the feeding pipe, and the loading chamber and the coating chamber are evacuated to the same vacuum degree by the exhaust mechanism. The gate valve between the loading chamber and the coating chamber is controlled to rise to connect the loading chamber and the coating chamber. The conveyor belt transports the loading platform into the coating chamber, places the loading platform on the pneumatic vibration mechanism of the coating chamber, and closes the gate valve.

[0020] Step 3: Vacuum the coating chamber through the vacuum mechanism, and heat the air inlet mechanism through the heating mechanism. The heating temperature is 100-300℃ and the heating time is 25-35min.

[0021] Step 4: Introduce the coating gas, heat it through the heating mechanism, introduce the carbon-containing coating gas into the porous gas distribution electrode plate through the air intake mechanism, maintain the gas pressure at 1Pa-100Pa, and evenly ionize the gas through the porous gas distribution electrode plate;

[0022] Step 5: Coating, the controller controls the pulse mechanism to ionize the coating gas to generate carbon ions, the pulse voltage is 1000V-40000V, the pulse frequency is 100Hz-50000Hz, the pulse width is 5μs-500μs, and the silicon powder is carbon coated through the bias mechanism; the bias voltage is 100V-3000V, the bias frequency is 100Hz-5000Hz, the bias pulse width is 5μs-500μs, and the coating time is 1h-5h;

[0023] Step 6: Vibration: The pneumatic vibrator vibrates through the vibration table to drive the stage to vibrate, and the silicon powder is dispersed according to the coating time and effect;

[0024] Step 7: Finished product, close the pulse mechanism and bias mechanism, the air intake mechanism stops delivering the coating gas, control the gate valve between the coating chamber and the discharge chamber to rise, so that the coating chamber and the discharge chamber are connected, and the conveyor belt transports the loading platform in the coating chamber to the discharge chamber, and introduces protective gas into the discharge chamber to obtain the finished product.

[0025] In the above description, further, in step 3, the vacuum is pumped to 1.0×10 -3 ~5×10 -4 Pa, heating temperature is 190-310℃.

[0026] Furthermore, in the above description, in step 4, argon gas is introduced through the air intake mechanism, the delivery ratio of argon gas to carbon-containing gas is 1:10, and the carbon-containing gas is benzene or methane.

[0027] Beneficial effects of the present invention:

[0028] 1. The charging chamber, coating chamber and discharging chamber are set in the furnace body, and the vacuum treatment can be effectively carried out on them through the exhaust mechanism to ensure the high purity of the working environment during the carbon-coated silicon process, avoid the influence of impurities on product quality, improve the purity and consistency of the product, and the conveyor belt can drive the workpiece to perform feeding, coating and discharging processing at the same time, thereby improving the coating production efficiency; the heating mechanism connected to the air intake mechanism heats the carbon-containing coating gas to increase the activity and activation cracking of the gas molecules, which is suitable for various carbon-containing gases. At the same time, the carbon-containing gas passes through the porous gas electrode plate so that it can enter The silicon powder can be pre-ionized and evenly distributed, thereby further improving the coating effect and efficiency; the pneumatic vibration mechanism drives the carrier on the conveyor belt to vibrate, and the silicon powder is dispersed by vibration according to the coating time and effect to adjust different vibration frequencies and amplitudes; the pulse mechanism and the bias mechanism are used in combination to achieve efficient ionization and deposition of the coating gas. The bias mechanism can provide different voltages, and the voltage, frequency, and pulse width can be adjusted for different coating processes, so that the plasma is deposited on the surface of the silicon substrate to form a high-quality carbon-coated silicon layer, thereby improving the quality and efficiency of the coating film layer.

[0029] 2. Through the precise operation of the plug-in valve in step 2, the interior of the furnace body is divided into a loading chamber, a coating chamber and a discharging chamber, and vacuum treatment is performed separately to make the working environment of each area reach the optimal state, reduce the influence of impurities on the coating process, and improve the stability and continuity of the production process; in step 4, the heating mechanism preheats the air inlet mechanism so that the coating gas reaches a suitable temperature before entering the coating chamber, thereby improving the activity and activation cracking of the gas molecules. At the same time, the design of the porous gas electrode plate enhances the uniform distribution and ionization of the coating gas in the coating chamber, thereby improving the coating efficiency and coating uniformity; in step 5, the silicon powder on the stage is vibrated by the pneumatic vibration mechanism to promote the attachment and penetration of carbon ions on the surface of the silicon powder and enhance the coating effect. In addition, by precisely controlling the parameters of the pulse mechanism and the bias mechanism (such as pulse voltage, frequency, pulse width and bias voltage, frequency, pulse width), fine regulation of the coating process is achieved, and the uniform deposition of carbon ions on the surface of the silicon powder is improved, thereby improving the quality and production efficiency of the carbon-coated silicon layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic structural diagram of a plasma-enhanced carbon-coated silicon device according to the present invention;

[0031] Figure 2 This is a schematic structural diagram of a pneumatic vibration mechanism in a plasma-enhanced carbon-coated silicon device according to the present invention;

[0032] Figure 3 This is a schematic structural diagram of a porous gas distribution electrode plate in a plasma enhanced carbon-coated silicon device of the present invention;

[0033] Figure 4 This is a cross-sectional structural diagram of a porous gas distribution electrode plate in a plasma-enhanced carbon-coated silicon device of the present invention;

[0034] Figure 5 Schematic diagram of a process of plasma-enhanced carbon-coated silicon method of the present invention;

[0035] Figure 6 This is a silicon powder coating energy spectrum diagram of a plasma-enhanced carbon-coated silicon method of the present invention;

[0036] Figure 7 This is a microscopic view of the carbon-coated silicon method described in Comparative Example 1 of the present invention;

[0037] Figure 8 This is a microscopic view of the carbon-coated silicon method described in Comparative Example 2 of the present invention;

[0038] Figure 9 This is a microscopic view of the carbon-coated silicon method described in Comparative Example 3 of the present invention;

[0039] The reference numerals in the figure are: 100-furnace body, 101-charging chamber, 102-coating chamber, 103-discharging chamber, 200-exhaust mechanism, 300-gate valve, 400-conveyor belt, 500-loading platform, 600-air intake mechanism, 601-air intake pipe, 700-heating mechanism, 800-porous cloth gas electrode plate, 801-air inlet, 802-air outlet, 900-pneumatic vibration mechanism, 901-pneumatic vibration head, 902-vibration table, 110-pulse mechanism, 120-bias mechanism, 130-air pressure monitoring mechanism, 140-feeding pipe. DETAILED DESCRIPTION

[0040] The present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

[0041] In this embodiment, refer to Figure 1-Figure 3 The plasma-enhanced carbon-coated silicon device specifically implemented herein includes a furnace body 100 and an exhaust mechanism 200 for evacuating the interior of the furnace body 100. A feed port and an exhaust port are formed at both ends of the furnace body 100, and a controller is provided on the furnace body 100. A charging chamber 101, a coating chamber 102 for plasma coating, and a discharge chamber 103 are formed in the furnace body 100 through openable and closable gate valves 300. The exhaust mechanism 200 is connected to the charging chamber 101, the coating chamber 102, and the discharge chamber 103 and can evacuate them. A rotatable conveyor belt 400 is provided in the furnace body 100. The conveying end of the conveyor belt 400 extends along the loading chamber 101, the coating chamber 102, and the discharge chamber 103. A loading platform 500 for placing workpieces is provided on the conveyor belt 400. The furnace body 100 is provided with an air intake mechanism 600 for supplying coating gas to the coating chamber 102. The air intake mechanism 600 is connected to a heating mechanism 700 for heating the coating gas. The end of the air intake mechanism 600 extending toward the coating chamber 102 is connected to a porous gas distribution electrode plate 800. A pneumatic vibration mechanism 900 is provided in the coating chamber 102 for vibrating the loading platform 500 on the conveyor belt 400.

[0042] A pulse mechanism 110 and a bias mechanism 120 are connected to the furnace body 100. The output end of the pulse mechanism 110 is connected to the air intake mechanism 600 and the furnace body 100. The pulse mechanism 110 is used to ionize the coating gas transported to the coating chamber 102. The delivery end of the bias mechanism 120 is connected to the furnace body 100 and the coating chamber 102. The bias mechanism 120 is used to deposit the coating gas.

[0043] The pulse mechanism 110 includes a high-voltage pulse power supply, and the bias mechanism 120 includes a bias power supply. Both the bias power supply and the high-voltage pulse power supply are electrically connected to the controller.

[0044] In an optional embodiment, the exhaust mechanism 200 includes a molecular pump, a mechanical pump, and a conduit. The mechanical pump is connected to the molecular pump, and the molecular pump is electrically connected to the loading chamber 101, the coating chamber 102, and the discharge chamber 103 via the conduit. The exhaust mechanism 200 controls the vacuuming within the furnace body 100 to ensure a high purity of the workpiece coating working environment, prevent impurities from affecting product quality, and improve product purity and consistency.

[0045] In an optional embodiment, the furnace body 100 is provided with a pressure monitoring mechanism 130 for monitoring the air pressure within the furnace. The pressure monitoring mechanism 130 includes a vacuum gauge and an automatic throttle valve. The vacuum gauge detects the air pressure within the furnace body 100 and controls the automatic throttle valve to control the air pressure in the control conduit. The pressure monitoring mechanism 130 monitors the vacuum pressure within the furnace body 100, thereby stabilizing the coating effect. The signal measured by the vacuum gauge is transmitted to the vacuum gauge, where it is amplified to determine the vacuum level within the chamber. This allows the throttle valve to control the air pressure within the chamber to meet the required standard.

[0046] In an optional embodiment, the air intake mechanism 600 includes an air intake pipe 601, a flow meter, and an air mixing barrel. The flow meter is electrically connected to the input end of the air mixing barrel. One end of the air intake pipe 601 is electrically connected to the output end of the air mixing barrel. The other end of the air intake pipe 601 extends into the coating chamber 102 and is connected to a porous gas electrode plate 800. The porous gas electrode plate 800 is formed with an air intake hole 801 and an air outlet hole 802 connected to the air intake hole 801. The air intake pipe 601 is electrically connected to the air intake hole 801. The air intake mechanism 600 can stably deliver carbon-containing gas, and the carbon-containing gas is introduced from the air intake hole 801 through the connected porous electrode plate and evenly distributed within the coating chamber 102 through the air outlet hole 802, thereby improving the coating quality and efficiency of the workpiece.

[0047] In an optional embodiment, the heating mechanism 700 includes a heating tube and a temperature control system. The heating tube is sleeved on one end of the air inlet pipe 601 extending into the coating chamber 102, and the end of the heating tube extends into the coating chamber 102. The heating tube is electrically connected to the temperature control system. By heating the air inlet pipe 601 by the heating mechanism 700, the carbon-containing gas passing through can be heated, thereby enhancing the activation and high-temperature cracking effect of the carbon-containing gas, thereby increasing the ionization rate of the carbon-containing gas passing through the porous cloth electrode plate. The temperature control system can accurately control the temperature rise rate, holding time, and cooling rate to ensure the ionization of the coated carbon-containing gas, thereby ensuring the conductivity of the silicon powder after coating.

[0048] In an optional embodiment, the pneumatic vibration mechanism 900 includes a pneumatic vibrator 901 and a vibration table 902. The vibration table 902 is installed on the conveyor belt 400 through a support frame. The pneumatic vibrator 901 is installed at the bottom of the furnace body 100, and the vibrating end of the pneumatic vibrator 901 extends through the furnace body 100 to the coating chamber 102, so that the vibration table 902 drives the loading platform 500 to be transported into the coating chamber 102, and the vibration table 902 is vibrated by the pneumatic vibrator 901.

[0049] Example 1

[0050] This embodiment provides a plasma-enhanced carbon-coated silicon method, which includes the following steps:

[0051] Step 1: using a plasma enhanced carbon-coated silicon device for coating;

[0052] Step 2: Feeding: The internal space of the furnace body 100 is divided into a loading chamber 101, a coating chamber 102, and a discharge chamber 103 by descending and closing the gate valve 300. Silicon powder is introduced into the loading chamber 101 through the feeding pipe 140 and onto the loading platform 500. The feeding pipe 140 is closed, and the loading chamber 101 and the coating chamber 102 are evacuated to the same vacuum level by the exhaust mechanism 200. The gate valve 300 between the loading chamber 101 and the coating chamber 102 is controlled to rise to connect the loading chamber 101 and the coating chamber 102. The loading platform 500 is transported into the coating chamber 102 by the conveyor belt 400 and placed on the pneumatic vibration mechanism 900 of the coating chamber 102. The gate valve 300 is closed.

[0053] Step 3: Vacuuming the coating chamber 102 to 1.0×10-3 Pa through the vacuum mechanism 200, and heating the air inlet mechanism 600 through the heating mechanism 700 at a heating temperature of 100° C. for 30 minutes;

[0054] Step 4: Introduce benzene as a coating gas, maintain the gas pressure at 5 Pa, pass it through the heating mechanism 700 to heat the coating gas, and introduce the carbon-containing coating gas into the porous gas distribution electrode plate 800 through the gas inlet mechanism 600, so that the gas is evenly ionized by the porous gas distribution electrode plate 800;

[0055] Step 5: Coating: The controller controls the pulse mechanism 110 to ionize the coating gas to generate carbon ions, with a pulse voltage of 1000 V, a pulse frequency of 100 Hz, and a pulse width of 5 μs. The bias mechanism 120 is then used to coat the silicon powder with carbon; the bias voltage is 100 V, the bias frequency is 100 Hz, the bias pulse width is 5 μs, and the coating time is 1 hour.

[0056] Step 6: Vibration: The pneumatic vibrator 901 vibrates the vibrating platform 902 to drive the stage 500 to vibrate. The silicon powder is dispersed by vibration according to the coating time and effect. The air pressure is adjusted to 6 MPa and the amplitude of the pneumatic vibrator 901 is 20 cm.

[0057] Step 7: Finished product, close the pulse mechanism 110 and the bias mechanism 120, the air intake mechanism 600 stops conveying the benzene coating gas, control the gate valve 300 between the coating chamber 102 and the discharge chamber 103 to rise, so that the coating chamber 102 and the discharge chamber 103 are connected, and the conveyor belt 400 conveys the loading platform 500 in the coating chamber 102 to the discharge chamber 103, and introduces the protective gas into the discharge chamber 103 to obtain the finished product.

[0058] In step 4, argon gas is introduced through the gas inlet mechanism 600, the delivery ratio of argon gas to carbon-containing gas is 1:10, and the carbon-containing gas is benzene.

[0059] Example 2

[0060] This embodiment differs from the first embodiment in that:

[0061] Step 3: Vacuuming the coating chamber 102 to 1.0×10-3 Pa through the vacuum mechanism 200, and heating the air inlet mechanism 600 through the heating mechanism 700 at a heating temperature of 300° C. for 30 minutes;

[0062] Step 4: Introduce the covering gas and maintain the pressure at 100 Pa;

[0063] Step 5: Coating, the controller controls the pulse mechanism 110 to ionize the coating gas to produce carbon ions, the pulse voltage is 10000V, the pulse frequency is 3000Hz, the pulse width is 100μs, and the silicon powder is carbon coated through the bias mechanism 120; the bias voltage is 3000V, the bias frequency is 1000Hz, the bias pulse width is 50μs, and the coating time is 5h. Other settings remain unchanged.

[0064] Example 3

[0065] This embodiment differs from the first embodiment in that:

[0066] Step 3: Vacuum the coating chamber 102 by the vacuum mechanism 200 to a pressure of 1.0×10-3 Pa, and heat the air inlet mechanism 600 by the heating mechanism 700 at a temperature of 200° C. for 30 minutes.

[0067] Step 4: Introduce benzene as the coating gas and maintain the pressure at 50 Pa;

[0068] Step 5: Coating, the controller controls the pulse mechanism 110 to ionize the coating gas to produce carbon ions, the pulse voltage is 5000V, the pulse frequency is 1000Hz, the pulse width is 500μs, and the silicon powder is carbon coated through the bias mechanism 120; the bias voltage is 1000V, the bias frequency is 500Hz, the bias pulse width is 100μs, and the coating time is 5h. Other settings remain unchanged.

[0069] Example 4

[0070] This embodiment differs from the first embodiment in that:

[0071] Step 3: Vacuuming the coating chamber 102 to 1.0×10-3 Pa through the vacuum mechanism 200, and heating the air inlet mechanism 600 through the heating mechanism 700 at a heating temperature of 300° C. for 30 minutes;

[0072] Step 4: Introduce benzene as the coating gas and maintain the pressure at 5 Pa;

[0073] Step 5: Coating, the controller controls the pulse mechanism 110 to ionize the coating gas to produce carbon ions, the pulse voltage is 40000V, the pulse frequency is 5000Hz, the pulse width is 500μs, and the silicon powder is carbon coated through the bias mechanism 120; the bias voltage is 2000V, the bias frequency is 5000Hz, the bias pulse width is 200μs, and the coating time is 5h. Other settings remain unchanged.

[0074] Reference Figure 6 As shown, the energy spectrum detection can be used to see that the surface of the silicon powder particles is evenly coated with carbon elements. The energy spectrum element ratio data of the carbon-coated particles obtained through the detection are shown in Table 1.

[0075] element Weight percentage (wt%) CK 70.7 SiK 29.3

[0076] Table 1

[0077] The weight percentage of carbon element is 70.7%, which proves that the present invention can evenly coat silicon powder with carbon.

[0078] In summary, through the experimental tests of the above comparative embodiments, in the experiments of carbon-coated silicon powder in Examples 1 to 4, the silicon powder can be uniformly coated using the above steps and parameters, and the uniform carbon coating can be further improved by adding a heating mechanism 700, a porous air electrode plate 800, a pneumatic vibration mechanism 900 and a bias mechanism 120.

[0079] Comparative Example 1

[0080] In this embodiment, refer to Figure 7The difference between this embodiment and the fourth embodiment is that:

[0081] Step 5: Coating. The controller controls the pulse mechanism 110 to ionize the coating gas to produce carbon ions. The pulse voltage is 40,000 V, the pulse frequency is 5,000 Hz, the pulse width is 500 μs, and the coating time is 5 hours. The bias mechanism 120 in step 5 is stopped, that is, the bias voltage, frequency, and pulse width are all 0, and other settings are not changed.

[0082] Comparative Example 2

[0083] In this embodiment, refer to Figure 8 The difference between this embodiment and the fourth embodiment is that:

[0084] Step 3: Vacuum the coating chamber 102 through the vacuum mechanism 200 to a vacuum level of 1.0×10-3 Pa;

[0085] Step 4: Introduce the covering gas benzene, maintain the gas pressure at 80Pa, introduce the carbon-containing covering gas into the porous gas distribution electrode plate 800 through the air intake mechanism 600, and uniformly ionize the gas through the porous gas distribution electrode plate 800. Remove the heating step of the heating mechanism 700 on the air intake pipe 601, and do not change other settings.

[0086] Comparative Example 3

[0087] In this embodiment, refer to Figure 9 The difference between this embodiment and the fourth embodiment is that:

[0088] In step six, the vibration of the pneumatic vibration mechanism 900 on the stage 500 is removed, and other settings remain unchanged.

[0089] Among them, in comparative example 1, the bias mechanism 120 was not added to perform the processing step, and the surface of the silicon powder particles was not completely covered with the carbon layer, resulting in poor coating effect; in comparative example 2, the carbon-containing gas was not subjected to the heating treatment step, resulting in benzene condensing on the inlet pipe 601, and only a small amount of gas entering the vacuum chamber, the plasma ionization amount was reduced, the coating film layer was thin, and the film quality was poor; in comparative example 3, the pneumatic dispersion treatment step was not performed, and microscopic observation showed that the surface of the silicon powder was unevenly coated, and the silicon powder at the bottom was coated with the carbon layer.

[0090] In summary, the plasma-enhanced carbon-coated silicon device and method designed in the present invention can improve the efficiency and quality of silicon powder coating.

[0091] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention is disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modifications to equivalent embodiments of equivalent changes by using the technical content disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments according to the technology of the present invention are all within the scope of the technical solution of the present invention without departing from the content of the technical solution of the present invention.

Claims

1. A plasma-enhanced carbon-coated silicon device, comprising a furnace body and an exhaust mechanism for evacuating the interior of the furnace body, wherein a feed inlet and a discharge inlet are formed at both ends of the furnace body, and a controller is provided on the furnace body, characterized in that: The furnace body is provided with a loading chamber, a coating chamber for plasma coating and a discharging chamber separated by an openable and closable plug-in valve. The exhaust mechanism is connected to the loading chamber, the coating chamber and the discharging chamber and can evacuate the chambers. A rotatable conveyor belt is provided in the furnace body, the conveying end of the conveyor belt extends along the loading chamber, the coating chamber and the discharging chamber, and a loading platform for placing workpieces is provided on the conveyor belt. An air intake mechanism for conveying coating gas to the coating chamber is provided on the furnace body, a heating mechanism for heating the coating gas is connected to the air intake mechanism, and a porous gas distribution electrode plate is connected to the end of the air intake mechanism extending to the coating chamber, and a pneumatic vibration mechanism for driving the loading platform on the conveyor belt to vibrate is provided in the coating chamber. The furnace body is connected to a pulse mechanism and a bias mechanism, the output end of the pulse mechanism is connected to the air inlet mechanism and the furnace body, the pulse mechanism is used to ionize the coating gas delivered to the coating chamber, the delivery end of the bias mechanism is connected to the furnace body and the coating chamber, and the bias mechanism is used to deposit the coating gas; The air extraction mechanism includes a molecular pump, a mechanical pump and several conduits. The mechanical pump is connected to the molecular pump, and the molecular pump is connected to the loading chamber, the coating chamber and the discharging chamber respectively through the conduits. The air intake mechanism includes an air intake pipe, a flow meter, and an air mixing barrel. The flow meter is conductively connected to the input end of the air mixing barrel. One end of the air intake pipe is conductively connected to the output end of the air mixing barrel. The other end of the air intake pipe extends into the interior of the coating chamber and is connected to a porous gas distribution electrode plate. The porous gas distribution electrode plate is formed with an air intake hole and a plurality of air outlet holes connected to the air intake hole. The air intake pipe is conductively connected to the air intake hole. The pneumatic vibration mechanism includes a pneumatic vibrator and a vibration table. The vibration table is installed on the conveyor belt through a support frame. The pneumatic vibrator is installed at the bottom of the furnace body, and the vibrating end of the pneumatic vibrator extends through the furnace body to the coating chamber, so that the vibration table drives the carrier to be transported into the coating chamber, and the vibration table is vibrated by the pneumatic vibrator. The pulse mechanism includes a high-voltage pulse power supply, and the bias mechanism includes a bias power supply. Both the bias power supply and the high-voltage pulse power supply are electrically connected to the controller.

2. The plasma-enhanced carbon-coated silicon device according to claim 1, characterized in that: The furnace body is provided with an air pressure monitoring mechanism for monitoring the air pressure inside the furnace. The air pressure monitoring mechanism includes a vacuum gauge and an automatic throttle valve baffle. The air pressure inside the furnace body is detected by the vacuum gauge, and the automatic throttle valve baffle is controlled by the vacuum gauge to control the air pressure delivery of the conduit.

3. The plasma-enhanced carbon-coated silicon device according to claim 1, characterized in that: The heating mechanism includes a heating tube and a temperature control system. The heating tube is sleeved on one end of the air inlet tube extending into the coating chamber, and the end of the heating tube extends into the coating chamber. The heating tube is electrically connected to the temperature control system.

4. A plasma-enhanced carbon-coated silicon method, characterized in that: The method comprises the following steps: Step 1: coating using a plasma-enhanced carbon-coated silicon device according to any one of claims 1 to 3; Step 2: Feeding: The internal space of the furnace body is divided into a loading chamber, a coating chamber, and a discharging chamber by lowering and closing the gate valve. Silicon powder is introduced into the loading platform in the loading chamber through the feeding pipe, and the loading chamber and the coating chamber are evacuated to the same vacuum degree by the exhaust mechanism. The gate valve between the loading chamber and the coating chamber is controlled to rise to connect the loading chamber and the coating chamber. The conveyor belt transports the loading platform into the coating chamber, places the loading platform on the pneumatic vibration mechanism of the coating chamber, and closes the gate valve. Step 3: Vacuum the coating chamber through the vacuum mechanism, and heat the air inlet mechanism through the heating mechanism. The heating temperature is 100-300℃ and the heating time is 25-35min. Step 4: Introduce the coating gas, heat it through the heating mechanism, introduce the carbon-containing coating gas into the porous gas distribution electrode plate through the air intake mechanism, maintain the gas pressure at 1Pa-100Pa, and evenly ionize the gas through the porous gas distribution electrode plate; Step 5: Coating, the controller controls the pulse mechanism to ionize the coating gas to generate carbon ions, the pulse voltage is 1000V-40000V, the pulse frequency is 100Hz-50000Hz, the pulse width is 5μs-500μs, and the silicon powder is carbon coated through the bias mechanism; the bias voltage is 100V-3000V, the bias frequency is 100Hz-5000Hz, the bias pulse width is 5μs-500μs, and the coating time is 1h-5h; Step 6: Vibration: The pneumatic vibrator vibrates through the vibration table to drive the stage to vibrate, and the silicon powder is dispersed according to the coating time and effect; Step 7: Finished product, close the pulse mechanism and bias mechanism, the air intake mechanism stops delivering the coating gas, control the gate valve between the coating chamber and the discharge chamber to rise, so that the coating chamber and the discharge chamber are connected, and the conveyor belt transports the loading platform in the coating chamber to the discharge chamber, and introduces protective gas into the discharge chamber to obtain the finished product.

5. The plasma-enhanced carbon-coated silicon method according to claim 4, characterized in that: In the step 3, the vacuum was pumped to 1.0×10 -3 ~5×10 -4 Pa, heating temperature is 190-310℃.

6. The plasma-enhanced carbon-coated silicon method according to claim 4, characterized in that: In the step 4, argon gas is introduced through the air intake mechanism, the delivery ratio of argon gas to carbon-containing gas is 1:10, and the carbon-containing gas is benzene or methane.

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