Plasma enhanced carbon-coated silicon device and method thereof

Abstract

The invention relates to a plasma enhanced carbon-coated silicon device and method in the field of lithium batteries, the plasma enhanced carbon-coated silicon device comprises a furnace body and an air exhaust 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 at intervals through gate valves, and a rotatable conveying belt is arranged in the furnace body; a conveyor belt is arranged on the furnace body, an objective table for placing a workpiece is arranged on the conveyor belt, a gas inlet mechanism is arranged on the furnace body, a heating mechanism for heating coating gas is connected to the gas inlet mechanism, a porous gas distribution electrode plate is connected to the end, extending towards the coating chamber, of the gas inlet mechanism, and a pneumatic vibration mechanism is arranged in the coating chamber; according to the carbon-coated silicon device and method, silicon powder is subjected to carbon coating, uniform coating can be achieved, and the coating uniformity and reliability can be further improved by additionally arranging the heating mechanism, the porous gas distribution electrode plate, the pneumatic vibration mechanism and the bias mechanism; 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 demand for high capacity and long driving range of lithium-ion batteries for new energy vehicles, traditional lithium-ion batteries with graphite as negative electrode materials can no longer meet the requirements. Silicon-based negative electrode materials are regarded as the ideal next-generation high-energy density lithium battery negative electrode materials due to their high theoretical specific capacity. In recent years, research on silicon-based negative electrode materials has mainly focused on effectively regulating volume changes and ensuring the conductivity of materials. Studies have shown that concepts such as nanostructures, active-inactive composite materials, and core-shell structures can effectively alleviate the stress generated by silicon-based materials during the cycle due to structural changes.

[0003] Therefore, the performance of silicon-based negative electrode materials is improved through different silicon-based nanostructures and methods, such as nano-sizing, carbon coating, alloying, using silicon oxide and pre-lithiation, etc. Among them, carbon coating is an effective method. On the one hand, carbon coating reduces the probability of direct contact between nano-silicon particles and electrolyte, stabilizes the interface, and prevents silicon from expanding and agglomerating. On the other hand, the graphitized carbon coating surface improves the electrical contact between particles and improves the conductive properties of the material.

[0004] However, although the existing carbon-coated silicon materials have significant advantages in the field of lithium-ion battery negative electrodes, their existing coating devices still have some defects. The existing coating devices are generally set up in a relatively simple manner, which makes it difficult to quickly transport and coat 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, in scientific research, the performance of carbon-coated silicon nanoparticles is studied by stirring carbon black, and the surface is coated by using carbon-containing organic matter, heating carbon-containing gas in a tubular furnace, and mixing graphite powder and silicon powder for ball milling. However, most of the current methods have the problems of 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, which leads to 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, so as to solve the technical problems that the structure of the existing silicon coating device in the above background technology is relatively simple and it is not easy to carry out uniform coating, and the coating effect of the existing silicon coating method is not good, which affects the coating efficiency and is not conducive to use.

[0007] The object of the present invention is achieved in the following ways:

[0008] A plasma enhanced carbon-coated silicon device comprises a furnace body and an exhaust mechanism for evacuating the interior of the furnace body, a feed port and an exhaust port are respectively formed at two ends of the furnace body, a controller is arranged on the furnace body, a charging chamber, a coating chamber for plasma coating and an exhaust chamber are formed in the furnace body through an openable and closable plug-in valve, the exhaust mechanism is connected with the charging chamber, the coating chamber and the exhaust chamber and can evacuate the charging chamber, the coating chamber and the exhaust chamber, a rotatable conveyor belt is arranged in the furnace body, the conveying end of the conveyor belt extends along the charging chamber, the coating chamber and the exhaust chamber, and a stage for placing workpieces is arranged on the conveyor belt, an air intake mechanism for conveying 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 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 stage on the conveyor 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 to the air intake mechanism and the furnace body. The pulse mechanism is used to ionize the coating gas transported to the coating chamber. The delivery end of the bias mechanism is connected to the furnace body and the coating chamber. The bias mechanism is used to deposit the coating gas.

[0010] Further in the above description, the air extraction mechanism includes a molecular pump, a mechanical pump and a plurality of conduits, the mechanical pump is connected to the molecular pump, and the molecular pump is respectively connected to the loading 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 inside the furnace, and 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 duct.

[0012] Further in the above description, 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, and the other end of the air intake pipe extends to the interior of the coating chamber and is connected to a porous air cloth electrode plate. An air intake hole and a plurality of air outlet holes connected to the air intake hole are formed on the porous air cloth electrode plate, and the air intake pipe is conductively connected to the air intake hole.

[0013] Further in the above description, the heating mechanism includes a heating tube and a temperature control system, the heating tube is sleeved on one end of the air inlet pipe extending into the coating chamber, and the end of the heating tube extends into the coating chamber, and the heating tube is electrically connected to 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 carrier table 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: coating using a plasma enhanced carbon-coated silicon device;

[0019] Step 2: Feeding, by closing the gate valve, the furnace body is partitioned into a loading chamber, a coating chamber and a discharging chamber, 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 through the exhaust mechanism, the gate valve between the loading chamber and the coating chamber is controlled to rise, so that the loading chamber and the coating chamber are connected, the conveyor belt transports the loading platform into the coating chamber, the loading platform is placed on the pneumatic vibration mechanism of the coating chamber, and the gate valve is closed;

[0020] Step 3: Vacuuming, vacuuming the coating chamber through the vacuum mechanism, heating 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 the coating gas 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 by 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 the sample carrier through the vibration table, and the silicon powder is dispersed by vibration 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 carrier in the coating chamber is transported to the discharge chamber by the conveyor belt, and the protective gas is introduced into the discharge chamber to obtain the finished product.

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

[0026] Further 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 vacuuming mechanism can effectively evacuate them 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, so as to improve the coating production efficiency; the heating mechanism connected to the air intake mechanism heats the carbon-containing coating gas to improve 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 to allow it to enter Pre-ionization is carried out and it can be evenly distributed, thereby further improving the coating effect and efficiency; the pneumatic vibration mechanism drives the stage 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 are 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 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, so that the working environment of each area reaches the optimal state, the influence of impurities on the coating process is reduced, and the stability and continuity of the manufacturing process are improved; in step 4, the heating mechanism preheats the air intake 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 a pneumatic vibration mechanism to promote the adhesion and penetration of carbon ions on the surface of the silicon powder and enhance the coating effect. In addition, by accurately controlling the parameters of the pulse mechanism and the bias mechanism (such as pulse voltage, frequency, pulse width and bias voltage, frequency, pulse width), the coating process is finely regulated, 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 It is a schematic structural diagram of a plasma enhanced carbon-coated silicon device of the present invention;

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

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

[0033] Figure 4 It 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 A schematic diagram of a 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 coating silicon method of the present invention;

[0036] Figure 7 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] Fig. 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 intake hole, 802-air outlet hole, 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 is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0041] In this embodiment, refer to Figure 1-Figure 3 A plasma enhanced carbon-coated silicon device specifically implemented therein comprises a furnace body 100 and an exhaust mechanism 200 for evacuating the interior of the furnace body 100, a feed port and an outlet port are formed at both ends of the furnace body 100, a controller is arranged on the furnace body 100, a charging chamber 101, a coating chamber 102 for plasma coating and an outlet chamber 103 are formed in the furnace body 100 through an openable and closable gate valve 300, the exhaust mechanism 200 is connected with the charging chamber 101, the coating chamber 102 and the outlet chamber 103 and can evacuate them, a rotatable conveyor belt 400 is arranged 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 discharging chamber 103, and a stage 500 for placing workpieces is provided on the conveyor belt 400, and an air intake mechanism 600 for conveying coating gas to the coating chamber 102 is provided on the furnace body 100, and a heating mechanism 700 for heating the coating gas is connected to the air intake mechanism 600, and a porous gas distribution electrode plate 800 is connected to the end of the air intake mechanism 600 extending to the coating chamber 102, and a pneumatic vibration mechanism 900 for driving the stage 500 on the conveyor belt 400 to vibrate is provided in the coating chamber 102;

[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 transport 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 respectively connected to the loading chamber 101, the coating chamber 102 and the discharge chamber 103 through the conduit. The exhaust mechanism 200 controls the vacuum in the furnace body 100 to ensure the high purity of the workpiece coating working environment, avoid the influence of impurities on product quality, and improve the purity and consistency of the product.

[0045] In an optional embodiment, the furnace body 100 is provided with an air pressure monitoring mechanism 130 for monitoring the air pressure in the furnace. The air pressure monitoring mechanism 130 includes a vacuum gauge and an automatic throttle valve baffle. The air pressure inside the furnace body 100 is detected by the vacuum gauge, and the air pressure transmission of the air pressure control conduit is controlled by the automatic throttle valve baffle. The air pressure monitoring mechanism 130 can monitor the vacuum pressure value inside the furnace body 100, and then stably control the coating effect. The signal measured by the vacuum gauge is transmitted to the vacuum gauge, and the vacuum degree in the room can be obtained after amplification processing, thereby controlling the air pressure inside the throttle valve control room 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 connected to the input end of the air mixing barrel, one end of the air intake pipe 601 is connected to the output end of the air mixing barrel, and the other end of the air intake pipe 601 extends into the coating chamber 102 and is connected to the 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, and the air intake pipe 601 is connected to the air intake hole 801. The air intake mechanism 600 can stably transport carbon-containing gas, and the carbon-containing gas is introduced from the air intake hole 801 through the connected porous electrode plate, and is evenly distributed in 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. The heating mechanism 700 heats the air inlet pipe 601, thereby heating the carbon-containing gas passing through, thereby enhancing the activation and high-temperature cracking effect of the carbon-containing gas, and 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 heating rate, the holding time, and the 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 vibration 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] Embodiment 1

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

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

[0052] Step 2: feeding, by closing the gate valve 300, the furnace body 100 is partitioned into a loading chamber 101, a coating chamber 102 and a discharging chamber 103, silicon powder is introduced into the loading chamber 101 through the feeding pipe 140 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 degree by the exhaust mechanism 200, the gate valve 300 between the loading chamber 101 and the coating chamber 102 is controlled to rise, so that the loading chamber 101 and the coating chamber 102 are connected, the loading platform 500 is transported to the coating chamber 102 by the conveyor belt 400, the loading platform 500 is placed on the pneumatic vibration mechanism 900 of the coating chamber 102, and the gate valve 300 is closed;

[0053] Step 3: vacuuming, vacuuming the coating chamber 102 through the vacuuming mechanism 200 to 1.0×10-3Pa, heating the air inlet mechanism 600 through the heating mechanism 700, the heating temperature is 100°C, and the heating time is 30 minutes;

[0054] Step 4: Introduce the covering gas benzene, maintain the gas pressure at 5 Pa, heat the covering gas through the heating mechanism 700, introduce the carbon-containing covering gas into the porous gas distribution electrode plate 800 through the gas inlet mechanism 600, and evenly ionize the gas through 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, the pulse voltage is 1000V, the pulse frequency is 100Hz, the pulse width is 5μs, and the silicon powder is carbon coated by the bias mechanism 120; the bias voltage is 100V, the bias frequency is 100Hz, the bias pulse width is 5μs, and the coating time is 1h;

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

[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] Embodiment 2

[0060] This embodiment is different from the first embodiment in that:

[0061] Step 3: Vacuuming: vacuuming the coating chamber 102 through the vacuuming mechanism 200 to 1.0×10-3Pa, and heating the air inlet mechanism 600 through the heating mechanism 700, the heating temperature is 300°C, and the heating time is 30 minutes;

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

[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, the coating time is 5h, and other settings are not changed.

[0064] Embodiment 3

[0065] This embodiment is different from the first embodiment in that:

[0066] Step 3: Vacuuming: vacuuming the coating chamber 102 through the vacuuming mechanism 200 to 1.0×10-3Pa, and heating the air inlet mechanism 600 through the heating mechanism 700, the heating temperature is 200°C, and the heating time is 30 minutes;

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

[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, the coating time is 5h, and other settings are not changed.

[0069] Embodiment 4

[0070] This embodiment is different from the first embodiment in that:

[0071] Step 3: Vacuuming: vacuuming the coating chamber 102 through the vacuuming mechanism 200 to 1.0×10-3Pa, and heating the air inlet mechanism 600 through the heating mechanism 700, the heating temperature is 300°C, and the heating time is 30 minutes;

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

[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, the coating time is 5h, and other settings are not changed.

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

[0075] element Weight percentage (wt%) CK 70.7 S K 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 above steps and parameters are used to carbon-coat silicon powder, 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 40000V, the pulse frequency is 5000Hz, the pulse width is 500μs, and the coating time is 5h. 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: Vacuuming the coating chamber 102 through the vacuum mechanism 200 to a vacuum level of 1.0×10-3Pa;

[0085] Step 4: Introduce the coating gas benzene, maintain the gas pressure at 80Pa, introduce the carbon-containing coating gas into the porous gas distribution electrode plate 800 through the air intake mechanism 600, make the gas uniformly ionized by 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 Fig. 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 a 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 it was observed through a microscope 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 the profession can make some changes or modifications to equivalent embodiments of equivalent changes by using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent changes and modifications made to the above embodiments according to the technology of the present invention are 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, 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 through an openable and closable plug-in valve, the exhaust mechanism is connected with 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; A pulse mechanism and a bias mechanism are connected to the furnace body. The output end of the pulse mechanism is connected to the air intake mechanism and the furnace body. The pulse mechanism is used to ionize the coating gas transported to the coating chamber. The delivery end of the bias mechanism is connected to the furnace body and the coating chamber. The bias mechanism is used to deposit the coating gas.

2. A plasma enhanced carbon-coated silicon device according to claim 1, characterized in that: The air extraction mechanism comprises a molecular pump, a mechanical pump and a plurality of conduits. The mechanical pump is connected to the molecular pump, and the molecular pump is respectively connected to the loading chamber, the coating chamber and the discharging chamber through the conduits.

3. A plasma enhanced carbon-coated silicon device according to claim 2, characterized in that: The furnace body is provided with an air pressure monitoring mechanism for monitoring the air pressure in 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 duct.

4. The plasma enhanced carbon-coated silicon device according to claim 1, characterized in that: 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, and the other end of the air intake pipe extends into the interior of the coating chamber and is connected to a porous air distribution electrode plate. An air intake hole and a plurality of air outlet holes connected to the air intake hole are formed on the porous air distribution electrode plate, and the air intake pipe is conductively connected to the air intake hole.

5. The plasma enhanced carbon-coated silicon device according to claim 4, 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.

6. The plasma enhanced carbon-coated silicon device according to claim 1, characterized in that: 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 vibration end of the pneumatic vibrator extends through the furnace body to the coating chamber, so that the vibration table drives the carrier table to be transported into the coating chamber, and the vibration table is vibrated by the pneumatic vibrator.

7. The plasma enhanced carbon-coated silicon device according to claim 1, characterized in that: 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.

8. 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 7; Step 2: Feeding, by closing the gate valve, the furnace body is partitioned into a loading chamber, a coating chamber and a discharging chamber, 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 through the exhaust mechanism, the gate valve between the loading chamber and the coating chamber is controlled to rise, so that the loading chamber and the coating chamber are connected, the conveyor belt transports the loading platform into the coating chamber, the loading platform is placed on the pneumatic vibration mechanism of the coating chamber, and the gate valve is closed; Step 3: Vacuuming, vacuuming the coating chamber through the vacuum mechanism, heating 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 the coating gas 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 by 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 the sample carrier through the vibration table, and the silicon powder is dispersed by vibration 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 carrier in the coating chamber is transported to the discharge chamber by the conveyor belt, and the protective gas is introduced into the discharge chamber to obtain the finished product.

9. The plasma enhanced carbon-coated silicon device according to claim 8, characterized in that: In step 3, the vacuum is evacuated to 1.0×10 -3 ~5×10 -4 Pa, heating temperature is 190-310℃.

10. The plasma enhanced carbon-coated silicon device according to claim 8, 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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