Functional substrate manufacturing method

Abstract

To provide a functional base material manufacturing method and others.SOLUTION: A functional base material manufacturing method includes: a reduction step (S21) of bringing a reduction gas into contact with a base material mainly composed of a compound containing at least phosphorus and a transition metal; and a carbonization step (S22) of bringing a carbonization gas into contact with the base material that has been in contact with the reduction gas.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a functional substrate manufacturing method, a functional substrate, a secondary battery, a positive electrode material, and a functional substrate manufacturing apparatus. [Background technology]

[0002] There are reactors that produce desired products by providing a predetermined atmosphere to powdered or granular materials to be processed. For example, a reactor commonly known as a rotary kiln heats a hollow reaction vessel that rotates around a central axis and passes the material through the reaction vessel while rolling it, thereby producing the desired product. Another reactor known as a roller hearth kiln produces the desired product by passing the material or workpiece through a tunnel-shaped reaction vessel. Various other reactors have also been developed.

[0003] For example, Patent Document 1 discloses the following reactor. The reactor has a screw feeder body that serves as a pressure reaction vessel, a catalyst supply section that introduces a catalyst into the screw feeder body, and a lower hydrocarbon supply section that introduces lower hydrocarbons into the screw feeder body. The reactor also has a screw that transports the produced nanocarbon, a solid delivery section that delivers the catalyst and nanocarbon transported by the screw, and a gas delivery section that delivers the produced hydrogen to the outside of the feeder body.

[0004] In response to this, the present inventors have investigated a method for producing a functional substrate. The functional substrate is a substrate whose main component is a compound containing at least phosphorus and a transition metal (e.g., lithium iron phosphate), and which contains nanocarbons (e.g., one or more carbon nanotubes) grown from the surface of the substrate. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-290682 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the reactor described in Patent Document 1 does not mention at all a method for producing a functional substrate.

[0007] Other objects and novel features will become apparent from the description of this specification and the accompanying drawings. [Means for solving the problem]

[0008] A method for producing a functional substrate according to one embodiment includes a reduction step in which a reducing gas is brought into contact with a substrate whose main component is a compound containing at least phosphorus and a transition metal, and a carbonization step in which a carbonization gas is brought into contact with the substrate that has been in contact with the reducing gas. [Effects of the Invention]

[0009] According to the present disclosure, it is possible to provide a functional substrate manufacturing method, a functional substrate, a secondary battery, a positive electrode material, and a functional substrate manufacturing apparatus. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a side view of a reaction apparatus according to a first embodiment. [Figure 2] FIG. 1 is a block diagram of a reaction apparatus according to a first embodiment. [Figure 3] 1 is a flowchart of a process performed by a reaction device. [Figure 4] FIG. 10 is a side view of a reaction apparatus according to a second embodiment. [Figure 5] FIG. 10 is a side view of a reaction apparatus according to a third embodiment. [Figure 6] 1A to 1C are diagrams illustrating a manufacturing process for a lithium ion battery (an example of a secondary battery according to the present disclosure). DETAILED DESCRIPTION OF THE INVENTION

[0011] The present invention will be described below through embodiments of the invention, but the invention according to the claims is not limited to the following embodiments. Furthermore, not all of the configurations described in the embodiments are necessarily essential means for solving the problems. For clarity of explanation, the following description and drawings have been omitted and simplified as appropriate. In each drawing, the same elements are assigned the same reference numerals, and duplicate explanations are omitted as necessary.

[0012] <First Embodiment (Reference Example)> The main configuration of a reaction apparatus according to the first embodiment (reference example) will be described with reference to Fig. 1. Fig. 1 is a side view of a reaction apparatus 10 according to the first embodiment. The reaction apparatus 10 shown in the figure is shown in a partially cutaway state for ease of understanding.

[0013] The reaction apparatus 10 is an apparatus for producing a product by applying conditions such as a predetermined physical stimulus to, for example, a powder or granular material to be treated. The reaction apparatus 10 includes a cylindrical reaction vessel 100, a material supply section (supply port 101) for supplying the material R10 to the reaction vessel 100, a conveying device (screw 120) for conveying the material R10 supplied to the reaction vessel 100 from the supply section side of the reaction vessel 100 to the discharge section side of the reaction vessel 100, a fluid supply section (first fluid inlet 131, first fluid outlet 132, first valve 134, etc.) for supplying a fluid that comes into contact with the material being conveyed into the reaction vessel 100, and a temperature control section (temperature control region 110, etc.) for controlling the temperature of the reaction vessel 100 in different regions along the axis AX100 of the reaction vessel 100. The physical stimulus is not particularly limited as long as it is a means used in the process of changing the processed material into a product, and examples of the physical stimulus include temperature changes such as heating and cooling. Examples of the physical stimulus include stress transmission such as stirring, mixing, kneading, and pulverization. Examples of the physical stimulus include reactions involving the exchange of electrons or radicals. Examples of the physical stimulus include contact with a catalyst.

[0014] In the reaction vessel 100, the material to be treated R10 supplied to the supply port 101 side of the reaction vessel 100 is heated while being transported to the discharge port 102 side of the reaction vessel 100, and a predetermined fluid that comes into contact with the transported material to be treated R10 is supplied into the reaction vessel 100, thereby continuously treating the material to be treated R10 (material to be treated) at a predetermined temperature. The material to be treated may be a solid, a fluid, or a mixture of both. Note that the reaction vessel 100 itself may be rotatable, or a rotatable screw 120 may be provided inside the reaction vessel 100, in order to agitate the material to be treated while transporting it.

[0015] The number and configuration of the reaction vessels 100 in the reaction apparatus 10 are not limited. The reaction vessels 100 may be configured, for example, as two or more reaction vessels connected in series or in parallel. In this case, each reaction vessel may be provided with a treatment material supply unit, a product delivery unit, a drive unit, a transport unit, a temperature control unit, a fluid supply unit, etc.

[0016] The type and state of the treated material are not particularly limited, but may be an inorganic material such as a metal oxide or metal sulfide containing lithium as one of its components, or an organic material such as a hydrocarbon. The treated material may be a solid such as a powder or granular material, or a fluid such as a liquid or gas. Furthermore, the treated material may pass through an intermediate during the process of changing into the product. The form and state of the intermediate are not particularly limited. For example, the intermediate may be the product of each reaction when two or more reactions are carried out in stages. In this case, the intermediate is, for example, an anhydrous compound produced by heating a hydrated compound. Alternatively, the intermediate is a fired body in which at least a portion of the treated material has undergone grain growth or sintering. The intermediate is in a state in which at least a portion of the treated material is liquefied or vaporized. The intermediate may also be in a form or state other than those described above.

[0017] Furthermore, the type and state of the product are not particularly limited, and the product may be a solid such as a powder or granular material, or a fluid such as a liquid or gas. The product may also be a mixture containing components other than the processed material, such as a catalyst or a transport auxiliary member. The product may also be a mixture containing two or more compounds, such as a main product and a by-product.

[0018] The shape and size of the processed material or product are not particularly limited, but when the shape is lumpy, the diagonal length is preferably 0.01 mm to 50 mm, more preferably 0.5 to 20 mm. Furthermore, when the shape of the processed material or product is lumpy, the ratio of the diagonal lengths (aspect ratio) is preferably 1 to 10, more preferably 1.3 to 1.8.

[0019] The reactor 10 mainly comprises a reaction vessel 100, a temperature control region 110, a screw 120, a first fluid control region 130, and a second fluid control region 140.

[0020] The reaction vessel 100 is, for example, a cylindrical cylinder, and has a supply port 101 for receiving a material to be treated and a product discharge port 102. The supply port 101 is an example of a material supply section of the present disclosure. The reaction vessel 100 also has an intermediate section between the supply port side (supply port 101) and the discharge port side (discharge port 102). The shape and configuration of the reaction vessel 100 are not particularly limited. For example, the cross-sectional shape of the reaction vessel 100 may be circular or elliptical, or may be polygonal such as rectangular, or may be any other shape. For example, the reaction vessel 100 may be made up of a single member, or may be made up of two or more connected members. When two or more members are connected, for example, a fastening means such as a bolt may be used at the points where the members are connected. The reactor vessel 100 is made of a material that can tolerate temperature changes that occur during the production of a product in the furnace and contact with materials (e.g., materials to be processed) supplied to the furnace and materials (e.g., products) produced. The reactor vessel 100 and the screw 120 can be made of, for example, alloys, ceramics, carbon, or composites containing two or more of these. Alloys are metal members containing at least one alloying element, such as nickel, cobalt, chromium, molybdenum, tungsten, tantalum, titanium, iron, copper, aluminum, silicon, boron, or carbon. Ceramics are ceramic members such as oxides, such as alumina and zirconia, carbides, such as silicon carbide and titanium carbide, nitrides, such as silicon nitride and titanium nitride, and borides, such as chromium boride. Carbon is a carbon member, such as crystalline graphite or fiber-reinforced graphite.

[0021] The reaction apparatus 10 shown in FIG. 1 is horizontally positioned and has a supply port 101 at the upper left end and a discharge port 102 at the lower right end. The reaction vessel 100 shown in FIG. 1 receives a material R10 to be treated through the supply port 101. The reaction apparatus 10 rotates a screw 120 provided inside the reaction vessel 100, thereby transporting the material R10 received in the reaction vessel 100 from the supply port 101 side of the reaction vessel 100 through an intermediate section A3 to the discharge port 102 side of the reaction vessel 100. The reaction apparatus 10 produces a product R11 from the material R10 by passing the material R10 through the intermediate section A3 of the reaction vessel 100. The reaction vessel 100 then discharges the produced product R11 through the discharge port 102.

[0022] The temperature control region 110 includes a temperature control device, i.e., a heating device or a cooling device, and controls the temperature of the reaction vessel at a predetermined position in the intermediate region A3 between the supply port 101 and the discharge port 102. The temperature control region 110 and the like are examples of temperature control units disclosed herein. The temperature control region 110 shown in FIG. 1 has a heating device surrounding the cylindrical reaction vessel 100 in the intermediate region A3 of the reaction vessel 100. The heating device includes any temperature-controllable heater, such as a sheath heater, coil heater, or ceramic heater. The heating device heats the reaction vessel 100 at a temperature ranging from room temperature to approximately 900°C. The temperature control region 110 can also set different temperatures for each region of the intermediate region A3 of the reaction vessel 100 along the axis AX120 of the screw 120 (described later). For example, the temperature control region 110 can control the temperature applied to the treatment material R10 in the first fluid control region 130 and the second fluid control region 140 (described later).

[0023] The temperature control area 110 may also include a control device for controlling a heating device or a cooling device. For example, the temperature control area 110 may have a thermometer for monitoring the temperature at a predetermined position in the reaction vessel 100. Furthermore, in the case where the heating device has a principle of heating by passing an electric current through it, the temperature of the reaction vessel 100 may be controlled by monitoring the electric current value.

[0024] The temperature control region 110 may be configured to perform heating or cooling by circulating water or oil, for example. The temperature control region 110 may also be configured to perform cooling by using a Peltier element, for example. With the above-mentioned configuration, the temperature control region 110 can set various temperature distributions in the reaction vessel 100 along the axis AX120 of the screw 120.

[0025] As described above, the temperature control region 110 can control the temperature of the reaction vessel 100 (middle portion A3) in each of different regions along the axis AX100 of the reaction vessel 100.

[0026] The screw 120 extends from the supply inlet 101 side to the discharge outlet 102 side of the reaction vessel 100, thereby rotating to convey the material R10 to be treated supplied from the supply inlet 101 toward the discharge outlet 102. The screw 120 shown in FIG. 1 has a spiral convex portion 121 formed around an axis extending in the left-right direction. As the convex portion 121 rotates while contacting the material R10 to be treated, the screw 120 conveys the material R10 from the left side to the right side in FIG. 1. The shape and conveying method of the conveying device of the present disclosure are not limited as long as it can convey the material to be treated or the product. The conveying device may be a screw provided inside the reaction vessel 100 so as to extend from the supply inlet 101 side to the discharge outlet 102 side of the reaction vessel 100, or the conveying device may be a drum provided inside the reaction vessel 100 so as to extend from the supply inlet 101 side to the discharge outlet 102 side of the reaction vessel 100. The transport device may be a belt conveyor provided inside the reaction vessel 100 so as to extend from the supply port 101 side to the discharge port 102 side of the reaction vessel 100. The transport device may be a blower provided inside the reaction vessel 100. The transport device may be a vibration generator provided inside the reaction vessel 100. The transport device may be other than those described above.

[0027] The size of the conveying device is not particularly limited, and may be shorter than the overall length of the reaction vessel 100, for example. The material from which the conveying device is made is not particularly limited, but it is desirable that the conveying device be made of a material that can tolerate temperature changes that occur during the production of a product and contact with substances supplied into the vessel, similar to the reaction vessel 100. The conveying device may be made of, for example, an alloy, ceramics, carbon, or a composite material containing two or more of these.

[0028] The shape of the convex portion 121 shown in FIG. 1 is an example, and the shape of the convex portion 121 is not limited to this. The convex portion 121 may have a different shape for each region of the reaction vessel 100. More specifically, for example, the helical pitch of the convex portion 121 may vary. Furthermore, the helical shape of the convex portion 121 may be two-stranded instead of one-stranded. Furthermore, the convex portion 121 may have a portion that is not helical. This allows the reaction device 10 to set, for each region, the movement speed and behavior of objects present inside the reaction vessel 100. More specifically, for example, the reaction device 10 transports, stirs, mixes, kneads, or pulverizes objects in the reaction vessel 100.

[0029] The screw 120 is journaled at both ends A1 and A2 of the reaction vessel 100. The screw 120 shown in FIG. 1 is connected (coupled) to a drive unit 150 at one end B1. The drive unit 150 is an example of a drive unit of the present disclosure. The drive unit 150 includes a motor 151 provided at one end A1 of the reaction vessel 100 and a reducer 152 provided between the motor 151 and one end A1 of the reaction vessel 100. The reducer 152 includes an input shaft coupled to the rotating shaft of the motor 151 and an output shaft coupled to one end B1 of the screw 120, and reduces the rotation of the rotating shaft of the motor 151 before transmitting it to the screw 120, thereby rotating the screw 120. The drive unit 150 may be configured to be able to change the rotation speed of the screw 120. In this case, the driving device 150 may be a motor with a variable rotation speed, or may be a combination of a motor with a fixed rotation speed and a reducer with a variable reduction ratio.

[0030] First fluid control region 130 includes first fluid inlet 131 and first fluid outlet 132 for passing a first fluid through reaction vessel 100 in a predetermined region in intermediate section A3. First fluid control region 130 is provided in reaction vessel 100 between supply port 101 and second fluid control region 140. First fluid inlet 131 is connected to first fluid supply pipe 133 and supplies the first fluid supplied from first fluid supply pipe 133 to reaction vessel 100. First fluid supply pipe 133 includes first valve 134 for adjusting the flow rate of the first fluid. First fluid outlet 132 is a hole for discharging the fluid in first fluid control region 130 to outside of reaction vessel 100.

[0031] With the above-described configuration, the reactor 10 reacts the material to be treated R10 with the first fluid in the first fluid control region 130 to produce an intermediate. The reactor 10 also discharges the reacted fluid out of the first fluid control region 130. The reactor 10 transports the material to be treated R10 or the product while the screw 120 rotates, and then contacts the first fluid, thereby promoting the reaction caused by the first fluid. The state or form of the first fluid is not limited as long as it has fluidity. That is, the first fluid may be a gas, a liquid, or a slurry in which powder or granular material is dispersed in a liquid. The first fluid may consist of one type of component, or two or more types of components.

[0032] The second fluid control region 140 includes a second fluid inlet 141 and a second fluid outlet 142 for passing the second fluid in a region in the intermediate portion A3 that is different from the first fluid control region 130. In other words, the second fluid control region 140 can have a configuration equivalent to that of the first fluid control region 130 in a region that is different from the first fluid control region 130.

[0033] Second fluid control region 140 is provided in reaction vessel 100 between first fluid control region 130 and outlet 102. Second fluid inlet 141 is connected to second fluid supply pipe 143, and supplies the second fluid supplied from second fluid supply pipe 143 to reaction vessel 100. Second fluid supply pipe 143 includes second valve 144 for adjusting the flow rate of the second fluid. Second fluid outlet 142 is a hole for discharging the fluid in second fluid control region 140 to the outside of reaction vessel 100.

[0034] With the above-described configuration, the reactor 10 reacts the intermediate that has passed through the first fluid control region 130 with the second fluid in the second fluid control region 140 to produce the product R11. The reactor 10 also discharges the reacted fluid to the outside of the second fluid control region 140. The state or form of the second fluid is not limited as long as it has fluidity. That is, the first fluid may be a gas, a liquid, or a slurry in which powder or granular material is dispersed in a liquid. The first fluid may consist of one type of component, or two or more types of components.

[0035] Although the configuration of the reaction apparatus 10 has been described above, the reaction apparatus 10 according to the first embodiment is not limited to the above configuration. For example, the number of screws 120 may be two or more as long as it is one or more. In other words, the reaction apparatus 10 may have a plurality of screws 120 arranged in parallel.

[0036] The cross-sectional shape of the screw 120 of the reaction vessel 100 in a plane perpendicular to the axis thereof may have a combination defined by a Reuleaux constant width figure. In this case, the cross-sectional shape of the convex portion 121 of the screw 120 has a shape combining multiple circular arcs corresponding to the Reuleaux constant width figures. For example, if the cross-sectional shape of the interior of the reaction vessel 100 is circular, the cross-sectional shape of the screw 120 has a Reuleaux constant width figure composed of three circular arcs.

[0037] The reaction vessel 100 is not limited to one lying parallel to the horizontal direction, but may be one having a predetermined angle with respect to the horizontal plane, and the reaction vessel 100 may have an inclined surface. The reaction device 10 has the first fluid control region 130 and the second fluid control region 140 in the middle section A3, but may also have a configuration for passing another fluid. In other words, the reaction device 10 may have three or more fluid control regions. The reaction device 10 is controlled by a control device described below.

[0038] Next, the function of the reaction apparatus 10 will be described with reference to Fig. 2. Fig. 2 is a block diagram of the reaction apparatus 10 according to the first embodiment. In addition to the configuration shown in Fig. 1, the reaction apparatus 10 has a control device 200, a temperature control device 210, a first fluid control device 230, a second fluid control device 240, and an information input / output unit 250.

[0039] The control device 200 is a circuit board including a computing device such as a CPU (Central Processing Unit) or an MCU (Micro Controller Unit). The control device 200 is communicably connected to each of the temperature control device 210, the first fluid control device 230, the second fluid control device 240, and the information input / output unit 250, and controls the configuration of each of these. The control device 200 realizes its functions using hardware and software implemented on the circuit board.

[0040] The control device 200 has, as its main functional components, an overall control unit 201, a temperature control unit 202, a screw rotation control unit 203, a first fluid control unit 204, a second fluid control unit 205, an IF control unit 206, and a memory unit 207. These functional components of the control device 200 may be integrated or may be discrete. Furthermore, these functional components of the control device 200 may be realized by the interlocking of multiple separate devices.

[0041] The overall control unit 201 is connected to each functional configuration of the control device 200 and controls the overall operation of these functions. For example, the overall control unit 201 can perform an operation such as issuing an operation instruction to the screw rotation control unit 203 depending on the state of the temperature supplied from the temperature control unit 202.

[0042] The temperature control section 202 is connected to the temperature control device 210 and controls the temperature of the reaction vessel 100 in the temperature control region 110. The temperature control section 202 has at least one of a heating device and a cooling device. The temperature control section 202 may also have one or more thermometers for controlling the temperature.

[0043] The screw rotation control unit 203 is connected to the drive device 150 and controls the operation of the drive device 150. The screw rotation control unit 203 may have, for example, a motor drive circuit for driving a motor (motor 151) included in the drive device 150. The screw rotation control unit 203 may also have a rotation sensor for monitoring the number of rotations of the motor (motor 151).

[0044] The first fluid control section 204 controls the flow of the first fluid in the first fluid control region 130. More specifically, the first fluid control section 204 is connected to the first fluid control device 230 and controls the operation of the first fluid control device 230. The first fluid control device 230 includes a first valve 134 for pumping the first fluid. The second fluid control section 205 controls the flow of the second fluid in the second fluid control region 140. More specifically, the second fluid control section 205 is connected to the second fluid control device 240 and controls the operation of the second fluid control device 240. The second fluid control device 240 includes a second valve 144 for pumping the second fluid.

[0045] The IF control unit 206 (IF = Interface) is connected to the information input / output unit 250 and is an interface for exchanging information with the user via the information input / output unit 250. That is, the IF control unit 206 receives operations from the user via the information input / output unit 250 and appropriately supplies information related to the received operations to each component of the control device 200. The IF control unit 206 also controls the state of a display unit included in the information input / output unit 250.

[0046] The storage unit 207 is a storage device including a nonvolatile memory such as a flash memory or an SSD (Solid State Drive). The storage unit 207 stores a program for the reaction device 10 to realize the functions of the present disclosure. The storage unit 207 also includes a volatile memory, and temporarily stores predetermined information when the control device 200 operates. The information input / output unit 250 has, for example, a button, a switch, or a touch panel for accepting operations from a user. The information input / output unit 250 also includes a display device for presenting information to a user.

[0047] The above describes the functional blocks of the reaction apparatus 10. With the above-described configuration, the reaction apparatus 10 transports the received material to be treated R10 using the screw 120, controls the temperature of the reaction vessel 100, and controls the atmosphere in the first fluid control region 130 and the second fluid control region 140.

[0048] Next, a product manufacturing method (product manufacturing method) executed by the reaction apparatus 10 will be described with reference to Fig. 3. Fig. 3 is a flowchart of the process executed by the reaction apparatus 10. The flowchart shown in Fig. 3 starts, for example, by starting the supply of the material to be treated R10 to the reaction apparatus 10.

[0049] First, the reaction device 10 receives a predetermined material to be treated R10 from the supply port 101 (step S11).

[0050] Next, the control device 200 of the reaction device 10 controls the temperature by driving the heating device or the cooling device in the temperature control region 110 of the reaction vessel 100 via the temperature control section 202 (step S12).

[0051] Next, the control device 200 of the reaction device 10 drives the drive device 150 via the screw rotation control unit 203. As a result, the drive device 150 rotates the screw 120. Then, the screw 120 transports the received material to be treated R10 toward the delivery port 102 (step S13).

[0052] Next, the control device 200 of the reaction device 10 controls the flow of the first fluid flowing through the first fluid control region 130 via the first fluid control unit 204 (step S14).

[0053] Next, the control device 200 of the reaction device 10 controls the flow of the second fluid flowing through the second fluid control region 140 via the second fluid control unit 205 (step S15).

[0054] Next, the reactor 10 discharges the product R11 that has passed through the second fluid control region 140 from the discharge port 102 (step S16).

[0055] The above has described the reaction method executed by the reaction apparatus 10. The above-mentioned method is shown along the flow from the reaction apparatus 10 producing the product R11 from the treated material R10 to discharging the produced product R11. However, the reaction apparatus 10 may perform the temperature control in step S12, for example, before step S11. Furthermore, for example, the reaction apparatus 10 may start step S14 and step S15 simultaneously.

[0056] The first embodiment (reference example) has been described above. While the reactor 10 described above has two fluid control regions (the first fluid control region 130 and the second fluid control region 140), the number of fluid control regions may be one or three or more. The reactor 10 may also have multiple temperature control regions 110 along the axis AX120 of the screw 120. The reactor 10 described above brings multiple fluids into contact with the material R10 received from the supply port 101 in the intermediate section A3. The reactor 10 also controls the temperature of the reaction vessel 100 along the axis AX120 of the screw 120 in the intermediate section A3. The reactor 10 can also apply a predetermined physical stimulus to the material R10 while transporting it. To apply a predetermined physical stimulus to the material R10, multiple reactors 10 may be connected in series or in parallel. The reaction apparatus 10 can simultaneously and accurately perform the above-mentioned atmosphere control, temperature control, and physical control. Therefore, according to the first embodiment, a reaction apparatus or the like that can efficiently manufacture a desired product can be provided.

[0057] <Embodiment 2> Next, as a second embodiment, a reaction apparatus 10A used for producing a functional substrate (functional active material) will be described with reference to Fig. 4. Fig. 4 is a side view of the reaction apparatus according to the second embodiment. The reaction apparatus 10A will be described below, focusing on differences from the reaction apparatus 10 of the first embodiment (reference example). Note that the same components as those of the reaction apparatus 10 of the first embodiment (reference example) are denoted by the same reference numerals, and descriptions thereof will be omitted where appropriate.

[0058] As shown in FIG. 4, the first fluid control region 130A is provided corresponding to the upstream region of the intermediate section A3 and includes a reducing gas inlet 131A and a reducing gas outlet 132A for passing the reducing gas through the reaction vessel 100 in the upstream region (first fluid control region 130A). In this disclosure, the terms upstream and downstream are defined as follows: At point A, which is an arbitrary position on the path from the supply port 101 to the delivery port 102, the position closer to the supply port 101 as viewed from point A is defined as the upstream position, and the position closer to the delivery port 102 as viewed from point A is defined as the downstream position. The upstream side refers to the upstream side as viewed from point A, and the downstream side refers to the downstream side as viewed from point A. The first fluid control region 130A is provided in the reaction vessel 100 between the supply port 101 and the second fluid control region 140A. The reducing gas inlet 131A is connected to a reducing gas supply pipe 133A connected to a reducing gas supply source, and the reducing gas supplied from the reducing gas supply pipe 133A is supplied to the reaction vessel 100. The reducing gas supply pipe 133A includes a first valve (not shown) for adjusting the flow rate of the reducing gas. The reducing gas outlet 132A is a hole for discharging the reducing gas in the first fluid control region 130A to the outside of the reaction vessel 100, and is connected to a reducing gas suction pipe 134A.

[0059] The second fluid control region 140A is provided corresponding to the downstream region of the intermediate section A3, and includes a carbonization gas inlet 141A and a carbonization gas outlet 142A in the downstream region (second fluid control region 140A) for passing the carbonization gas into the reaction vessel 100. In other words, the second fluid control region 140A may have a configuration equivalent to that of the first fluid control region 130A in a region different from the first fluid control region 130A.

[0060] Second fluid control region 140A is provided in reaction vessel 100 between first fluid control region 130A and delivery port 102. Carbonizing gas inlet 141A is connected to carbonizing gas supply pipe 143A, and supplies the carbonizing gas supplied from carbonizing gas supply pipe 143A to reaction vessel 100. Carbonizing gas supply pipe 143A includes a second valve (not shown) for adjusting the flow rate of the carbonizing gas. Carbonizing gas outlet 142A is a hole for discharging the carbonizing gas in second fluid control region 140A to the outside of reaction vessel 100, and is connected to carbonizing gas suction pipe 144A.

[0061] In addition, a reducing gas outlet 160 is provided between the first fluid control region 130A and the second fluid control region 140A. The reducing gas outlet 160 is a hole for discharging the reducing gas from the first fluid control region 130A and the reducing gas from the second fluid control region 140A to the outside of the reaction vessel 100, and is connected to a reducing gas suction pipe 161.

[0062] The reducing gas inlet 131A is an example of a reducing gas supply unit of the present disclosure, and the carbonizing gas inlet 141A is an example of a carbonizing gas supply unit of the present disclosure.

[0063] Next, the route of the reducing gas will be described.

[0064] In the reaction apparatus 10A having the above configuration, a portion of the reducing gas supplied from the reducing gas inlet 131A is sucked into the reducing gas outlet 132A connected to the reducing gas suction pipe 134A, and is forcibly discharged to the outside of the reaction vessel 100 through the reducing gas outlet 132A and the reducing gas suction pipe 134A connected thereto. As a result, a reducing gas flow (see arrow AR1 in FIG. 4) is generated in the first fluid control region 130A from the reducing gas inlet 131A toward the reducing gas outlet 132A.

[0065] Another part of the reducing gas supplied from the reducing gas inlet 131A is sucked into the reducing gas outlet 160 connected to the reducing gas suction pipe 161, and is forcibly discharged to the outside of the reaction vessel 100 through the reducing gas outlet 160 and the reducing gas suction pipe 161 connected thereto. As a result, a reducing gas flow (see arrow AR2 in FIG. 4) is generated in the first fluid control region 130A from the reducing gas inlet 131A toward the reducing gas outlet 160.

[0066] The reducing gas flow (see arrows AR1 and AR2 in FIG. 4) is controlled to a predetermined temperature by the temperature control region 110 heating the reaction vessel 100. Then, the reducing gas flow controlled to this predetermined temperature comes into contact with the treatment material (e.g., LiFePO4) passing through the first fluid control region 130A, as described below.

[0067] Next, the route of the carbonizing gas will be described.

[0068] In the reaction apparatus 10A having the above configuration, a portion of the carbonization gas supplied from the carbonization gas inlet 141A is sucked into the carbonization gas outlet 142A connected to the carbonization gas suction pipe 144A, and is forcibly discharged to the outside of the reaction vessel 100 through the carbonization gas outlet 142A and the carbonization gas suction pipe 144A connected thereto. As a result, a carbonization gas flow (see arrow AR3 in FIG. 4) is generated in the second fluid control region 140A from the carbonization gas inlet 141A toward the carbonization gas outlet 142A.

[0069] Another portion of the carbonization gas supplied from the carbonization gas inlet 141A is sucked into the reducing gas outlet 160 connected to the reducing gas suction pipe 161, and is forcibly discharged outside the reaction vessel 100 through the reducing gas outlet 160 and the reducing gas suction pipe 161 connected thereto. This generates a carbonization gas flow (see arrow AR4 in FIG. 4) in the second fluid control region 140A that flows from the carbonization gas inlet 141A toward the reducing gas outlet 160.

[0070] The carbonization gas flow (see arrows AR3 and AR4 in FIG. 4) is controlled to a predetermined temperature by the temperature control region 110 heating the reaction vessel 100. Then, the carbonization gas flow controlled to this predetermined temperature comes into contact with the material to be treated (for example, LiFePO4 after the reduction step described below) passing through the second fluid control region 140A as described below.

[0071] Furthermore, as will be described later, the reducing gas (hydrogen) generated in the carbonization step in the second fluid-control region 140A is sucked into the reducing gas outlet 160 connected to the reducing gas suction pipe 161, and is forcibly discharged to the outside of the reaction vessel 100 via the reducing gas outlet 160 and the reducing gas suction pipe 161 connected thereto. This generates a reducing gas flow (see arrow AR4 in FIG. 4) in the second fluid-control region 140A from the carbonization gas inlet 141A toward the reducing gas outlet 160. The reducing gas discharged from the reducing gas outlet 160 may be reused by being supplied again into the reaction vessel 100 from the reducing gas inlet 131A.

[0072] <Method of manufacturing functional substrate> Next, with reference to FIG. 4, a method for producing a functional substrate using the reaction apparatus 10A will be described. The functional substrate refers to a substrate whose main component is, for example, a compound containing at least phosphorus and a transition metal (e.g., lithium iron phosphate), and which contains nanocarbons (e.g., one or more carbon nanotubes) growing from at least a portion of the surface of the substrate. In the present disclosure, the transition metal is not particularly limited to any particular element as long as it is an element belonging to the transition metals in the periodic table, i.e., an element belonging to Groups 3 to 11 of the periodic table. The transition metal may be, for example, iron, cobalt, or nickel. The compound may contain one or more types of transition metals. That is, the compound may contain, for example, iron and nickel in a predetermined ratio.

[0073] In addition, in this disclosure, nanocarbon refers to a material whose main component is carbon and whose diameter or short side is 1000 nanometers or less. Nanocarbon may be, for example, carbon nanotubes, carbon fibers, graphene, carbon black, fullerene, etc.

[0074] Hereinafter, a method for producing a functional substrate (C-LiFePO4) containing lithium iron phosphate as the main component and containing carbon nanotubes grown from the surface thereof will be described.

[0075] The "C~" in C~LiFePO4 represents one or more carbon nanotubes grown (mainly through the carbonization process described below) on the surface of LiFePO4 (mainly the surface activated through the reduction process described below) as the starting point (see "Product" at the bottom right of Figure 4). That is, the notation C~LiFePO4 is used for convenience in describing the present disclosure to express the state in which carbon nanotubes are grown on the surface of a substrate primarily composed of lithium iron phosphate. Note that the shape, form, chemical components, chemical composition, and crystalline structure of the substrate are not particularly limited as long as nanocarbons can be generated on its surface. The shape of the substrate may be, for example, spherical, blocky, or plate-like. The form of the substrate may be, for example, a powder or granular material. The substrate may be, for example, a form in which multiple substances are bonded together. Furthermore, the substrate may have the same chemical components and chemical composition as a compound containing at least phosphorus and a transition metal. That is, the substrate may be a compound containing at least phosphorus and a transition metal. The substrate may be, for example, LiFePO4.

[0076] First, the prerequisites for carrying out the method for producing the functional base material (C-LiFePO4) will be described.

[0077] Hereinafter, a substrate containing lithium iron phosphate (for example, lithium iron phosphate having an olivine crystal structure) as a main component is used as the material to be treated. Hereinafter, this will be referred to as LiFePO4 or LFP. The shape of the substrate is not particularly limited, but it is preferably a powder or granular material. When the substrate is in the form of a powder or granular material, the average particle diameter is preferably 500 μm or less, more preferably 1 to 200 μm, and even more preferably 10 to 50 μm. When the average particle diameter of the substrate is within the above range, the carbonization reaction can proceed efficiently. The average particle diameter may be a value measured, for example, by a laser diffraction / scattering particle size distribution measuring device (for example, Partica LA-960V2 manufactured by Horiba, Ltd.).

[0078] It is also preferable to use hydrogen as the reducing gas. Hereinafter, hydrogen will be referred to as H2. However, the reducing gas is not limited to hydrogen as long as it has reducing properties. The reducing gas may be, for example, carbon monoxide.

[0079] It is preferable to use methane, a lower hydrocarbon, as the carbonization gas. Hereinafter, this will be referred to as CH4. However, the carbonization gas is not limited to methane as long as it has carbonizing properties. The carbonization gas may be, for example, propane.

[0080] The supply flow rate (space velocity: SV value) of H2 from the reducing gas inlet 131A to the reaction vessel 100 (first fluid control region 130A) is preferably 80,000 NL / kg / h or less, and more preferably 40,000 to 80,000 NL / kg / h. Here, NL represents the volume of hydrogen supplied (normal lube), / kg represents the unit weight (per kilogram) of the base material whose main component is lithium iron phosphate, and / h represents the unit time (per hour) for supplying hydrogen.

[0081] The preferred heating temperature for the upstream region (first fluid control region 130A) of intermediate section A3 is 300 to 1000°C. To facilitate smoother reactions in the upstream region (first fluid control region 130A), the more preferred heating temperature for the upstream region (first fluid control region 130A) of intermediate section A3 is 500 to 700°C, and even more preferably 650°C. Note that in the present disclosure, the heating temperature refers to the temperature of the heating device in the temperature control region, and the temperature of the heating device is the temperature measured by a temperature measuring means such as a thermocouple attached to the heating device.

[0082] On the other hand, the supply flow rate (space velocity: SV value) of lower hydrocarbons (here, CH4) from the carbonization gas inlet 141A to the reaction vessel 100 (second fluid control region 140A) is preferably 80,000 NL / kg / h or less, more preferably 40,000 to 80,000 NL / kg / h, in methane equivalent. NL represents the volume of methane supplied (normal lube), / kg represents the unit weight (per kilogram) of lithium iron phosphate, and / h represents the unit time (per hour) for methane supply. If the SV value is less than 40,000 NL / kg / h, the carbonization reaction will not proceed satisfactorily. If the SV value exceeds 80,000 NL / kg / h, the conversion rate will decrease, and the reaction efficiency will deteriorate.

[0083] The preferred heating temperature for the downstream region (second fluid control region 140A) of the intermediate section A3 is 300 to 1000°C. To facilitate smoother reactions in the downstream region (second fluid control region 140A), the more preferred heating temperature for the downstream region (second fluid control region 140A) of the intermediate section A3 is 600 to 800°C, and even more preferably 750°C.

[0084] The manufacturing method of C~LiFePO4 is carried out on the above premise.

[0085] First, a base material (here, powdered LiFePO4) mainly composed of a compound containing at least phosphorus and a transition metal is prepared as the material to be treated and supplied to the supply port 101 side of the reaction vessel 100 through the supply port 101 (step S20). The LiFePO4 supplied to the supply port 101 side of the reaction vessel 100 is transported by the rotating screw 120 from the supply port 101 side of the reaction vessel 100 through the intermediate section A3 to the outlet 102 side of the reaction vessel 100. From the viewpoint of sufficiently carrying out the reaction, it is desirable to set this transport speed slow enough not to impair productivity. For example, the transport speed is desirably 10 meters per hour or less, more desirably 5 meters per hour or less, and even more desirably 1 meter per hour or less. LiFePO4 may be pretreated. Examples of pretreatment include mechanical milling, jet milling, and electroless plating. Pretreatment includes a process for amorphizing at least a portion of LiFePO4, other than the above. Pretreatment includes a process for attaching a transition metal to at least a portion of LiFePO4, other than the above. Mechanical milling may involve, for example, using a planetary ball mill, placing LiFePO4 and 5 mm diameter chrome steel balls in a chrome steel container, filling the container with argon gas as an inert gas, and then rotating the container at 500 rpm for 24 hours. Jet milling may involve, for example, using a wet jet mill, circulating a slurry of LiFePO4 and a small amount of iron powder dispersed in isopropyl alcohol through the jet mill channel 10 times. By pretreating LiFePO4 in this way, a substrate primarily composed of LiFePO4 may be produced.

[0086] Next, a reduction step is performed in the upstream region (first fluid-control region 130A) of intermediate section A3 (step S21). In this reduction step, H2 (see arrows AR1 and AR2 in FIG. 4) supplied from reducing gas inlet 131A to first fluid-control region 130A directly contacts the substrate (here, the substrate mainly composed of LiFePO4) passing through the first fluid-control region 130A, thereby reducing at least a portion of the substrate passing through the first fluid-control region 130A. Note that H2 (see arrows AR1 and AR2 in FIG. 4) supplied from reducing gas inlet 131A reduces the atmosphere surrounding the substrate (here, the substrate mainly composed of LiFePO4), and the substrate may be indirectly reduced via this reduced atmosphere. Thus, the "reduction step of contacting a reducing gas with a substrate" in the present disclosure includes not only cases in which the substrate is directly reduced by the reducing gas (here, H2), but also cases in which the substrate is indirectly reduced by the reducing gas (here, H2).

[0087] Thereafter, in the downstream region (second fluid-control region 140A) of intermediate section A3, a carbonization process is carried out (step S22). In this carbonization process, CH4 (see arrows AR3 and AR4 in FIG. 4) supplied from carbonization gas inlet 141A to second fluid-control region 140A comes into contact with the base material (here, the base material mainly composed of LiFePO4) that has undergone the reduction process and passes through second fluid-control region 140A, causing a reaction of LiFePO4 + CH4 → C-LiFePO4 + 2H2, producing C-LiFePO4 and H2.

[0088] The product C~LiFePO4 produced by these steps is discharged and collected from the outlet 102 to the outside of the reaction vessel 100. Meanwhile, H2 produced in step S22 is discharged from the reducing gas outlet 160 to the outside of the reaction vessel 100 and is supplied again into the reaction vessel 100 from the reducing gas inlet 131A.

[0089] As described above, according to the second embodiment, it is possible to produce a functional substrate, i.e., a substrate whose main component is a compound containing at least phosphorus and a transition metal (e.g., lithium iron phosphate), and which contains nanocarbons (e.g., one or more carbon nanotubes) grown starting from its surface.

[0090] <Third Embodiment> Next, as a third embodiment, a reaction apparatus 10B used for producing a functional substrate will be described with reference to FIG. 5. FIG. 5 is a side view of the reaction apparatus according to the third embodiment. The following describes the reaction apparatus 10B, focusing on differences from the reaction apparatus 10A of the second embodiment. Note that the same components as those of the reaction apparatus 10A of the second embodiment are denoted by the same reference numerals, and descriptions thereof will be omitted as appropriate. Note that for convenience of description, the reaction apparatus 10A of the second embodiment and the second reaction apparatus 10A of the third embodiment are depicted in a simplified form in FIG. 5.

[0091] As shown in Fig. 5, the reactor 10B is configured by combining the reactor 10 of the first embodiment and the reactor 10A of the second embodiment. Hereinafter, the reactor 10 of the first embodiment will be referred to as the first reactor 10, and the reactor 10A of the second embodiment will be referred to as the second reactor 10A. Specifically, the outlet 102 of the first reactor 10 and the supply port 101 of the second reactor 10A are connected to each other.

[0092] The first reactor 10 produces the intermediate LiFePO4.

[0093] Next, a method for producing the intermediate LiFePO4 using this reaction apparatus 10A will be described.

[0094] First, the prerequisites for carrying out the method for producing the intermediate LiFePO4 will be described.

[0095] Hereinafter, Li3PO4 and Fe3(PO4)2·8H2O will be used as the processed materials. However, the processed materials are not limited to the above as long as they are compounds that can be used to produce the intermediate LiFePO4.

[0096] The heating temperature of the middle section A3 of the first reactor 10 is, for example, 400° C. Also, it is assumed that H 2 is supplied into the reaction vessel 100 of the first reactor 10.

[0097] The method for producing the intermediate LiFePO4 is carried out on the above premise.

[0098] First, the processed materials, Li3PO4 and Fe3(PO4)2·8H2O, are supplied from the supply port 101 of the first reactor 10 to the supply port 101 side of the reaction vessel 100 of the first reactor 10. The Li3PO4 and Fe3(PO4)2·8H2O supplied to the supply port 101 side of this reaction vessel 100 are transported from the supply port 101 side of the reaction vessel 100 of the first reactor 10 to the delivery port 102 side of this reaction vessel 100 by the rotating screw 120 of the first reactor 10, passing through the intermediate section A3.

[0099] At this time, in the intermediate section A3 of the first reactor 10, H2 supplied into the reaction vessel 10 of the first reactor 10 comes into contact with Li3PO4 and Fe3(PO4)2·8H2O passing through the intermediate section A3, causing a predetermined reaction to occur and producing the intermediate LiFePO4.

[0100] The intermediate LiFePO4 thus produced is supplied from the outlet 102 of the first reactor 10 and the supply port 101 of the second reactor 10A to the supply port 101 side in the reaction vessel 100 of the second reactor 10A.

[0101] Thereafter, the method for producing C~LiFePO4 described in the second embodiment is carried out in the second reactor 10B. As a result, the product C~LiFePO4 is produced. The produced product C~LiFePO4 is discharged from the outlet 102 of the second reactor 10B to the outside of the reaction vessel 100 of the second reactor 10B and collected in the collection section.

[0102] As described above, according to the third embodiment, it is possible to produce a functional substrate, i.e., a substrate whose main component is a compound containing at least phosphorus and a transition metal (e.g., lithium iron phosphate), and which contains nanocarbons (e.g., one or more carbon nanotubes) grown starting from its surface.

[0103] <Fourth Embodiment> Next, as a fourth embodiment, a manufacturing process for a lithium ion battery (an example of a secondary battery of the present disclosure) will be described with reference to Fig. 6. Fig. 6 is a diagram illustrating the manufacturing process for a lithium ion battery (an example of a secondary battery of the present disclosure).

[0104] As shown in FIG. 6, the manufacturing process of a lithium ion battery includes a C~LiFePO4 manufacturing step, a kneading step, a coating step, and a lamination step, and a lithium ion battery is finally manufactured through these steps.

[0105] The C~LiFePO4 production process is a process for producing C~LiFePO4 using the reaction apparatus 10A of the second embodiment or the reaction apparatus 10B of the third embodiment.

[0106] The kneading step is a step in which a binder is added to the C-LiFePO4 produced in the C-LiFePO4 step, and the mixture is kneaded using a twin-screw kneading extruder or the like to produce a slurry (dispersion liquid) containing C-LiFePO4.

[0107] The coating step is a step in which the slurry containing C~LiFePO4 produced in the kneading step is applied to a current collector using a die coater, etc. The current collector coated with the slurry containing C~LiFePO4 is the positive electrode (positive electrode material).

[0108] The lamination step is a step in which the positive electrode (positive electrode material), electrolyte, negative electrode, etc. produced in the coating step are laminated together using a laminating press or the like.

[0109] Through the above steps, a lithium-ion battery is manufactured.

[0110] Next, the advantages of using C~LiFePO4 will be described.

[0111] Generally, in secondary batteries, carbon nanotubes are used in addition to LiFePO4 to facilitate the transfer of electrons. However, since carbon nanotubes are usually separate from LiFePO4, there are many gaps between the two, making it difficult to transfer electrons more smoothly.

[0112] In contrast, the C~LiFePO4 produced by the reaction apparatus 10A of the second embodiment or the reaction apparatus 10B of the third embodiment contains one or more carbon nanotubes (mainly grown through a carbonization process) that originate from the surface (mainly the surface activated through a reduction process) (see "Product" at the bottom right of FIG. 4). That is, in the C~LiFePO4 produced by the reaction apparatus 10A of the second embodiment or the reaction apparatus 10B of the third embodiment, the carbon nanotubes (mainly grown through a carbonization process) are in close contact with the surface of the LiFePO4, with no gaps between them. Therefore, when this C~LiFePO4 is used in a secondary battery, electron transfer can be performed more smoothly. This can further improve the performance of the secondary battery. For example, it is possible to further reduce the size and increase the capacity of the secondary battery.

[0113] In addition, C~LiFePO4 may be applied not only to the positive electrode material of a liquid-based lithium ion battery, but also to at least a part of the positive electrode, solid electrolyte, intermediate layer between the positive electrode and the electrolyte, etc. of an all-solid-state battery (e.g., a sulfide-based all-solid-state lithium ion battery).

[0114] Next, a modified example will be described.

[0115] In the above-described second and third embodiments, lithium iron phosphate is used as the treated material, but the present invention is not limited thereto. For example, sodium iron phosphate may be used as the treated material. That is, the treated material may be any base material whose main component is a compound (e.g., a positive electrode active material) containing at least phosphorus and a transition metal.

[0116] The invention made by the inventor has been specifically described above based on the embodiments, but it goes without saying that the present invention is not limited to the embodiments already described, and various modifications are possible within the scope of the gist of the invention. [Explanation of symbols]

[0117] 10...Reactor (first reactor) 10A...Reactor (second reactor) 100...Reaction vessel 101...supply port 102…Outlet port 110...Temperature control area 120...Screw 121...Convex part 130...First fluid control region 130A...First fluid control area 131...1st fluid inlet 131A...Reducing gas inlet 132…1st fluid outlet 132A...Reducing gas outlet 133...First fluid supply pipe 133A...Reducing gas supply pipe 134...First valve 134A...Reducing gas suction pipe 140...Second fluid control region 140A...Second fluid control area 141…Second fluid inlet 141A...Carbonization gas inlet 142…Second fluid outlet 142A...Carbonization gas outlet 143…Second fluid supply pipe 143A...Carbonization gas supply pipe 144...Second valve 144A...Carbonization gas suction tube 150...Driver 151...Motor 152...Reducer 160...Reducing gas outlet 161...Reducing gas suction tube 200...Control device 201... Overall control unit 202...Temperature control unit 203...Screw rotation control section 204...First fluid control section 205...Second fluid control section 206...IF control section 207...Storage section 210...Temperature control device 230...First fluid control device 240...Second fluid control device 250...Information input / output section R10: Processing material R11...Product

Claims

1. Lithium iron phosphate (LiFePO ) was fed into a cylindrical reaction vessel including an intermediate portion between a supply inlet and a delivery outlet. 4 A method for producing a functional substrate, comprising growing nanocarbon starting from at least a portion of the surface of a compound containing at least The compound is composed of powder particles having an average particle size of 10 to 50 μm, a reduction step of contacting the compound with a reducing gas while transporting the compound from a supply port toward an outlet; a first carbonization step of contacting the compound with a carbonization gas while flowing the carbonization gas in a direction opposite to the direction in which the compound is transported, after the reduction step; a second carbonization step of contacting the carbonization gas with the compound while flowing the carbonization gas in the same direction as the direction in which the compound is transported, after the first carbonization step; a recycling step of using the hydrogen generated in the first carbonization step in the reduction step.

2. The reduction step includes a first reduction step of contacting the compound with the reducing gas while flowing the reducing gas in a direction opposite to a direction in which the compound is transported; 2. The method for producing a functional substrate according to claim 1, further comprising: a second reduction step, after the first reduction step, of bringing the reducing gas into contact with the compound while flowing the reducing gas in the same direction as the direction in which the compound is transported.

3. 3. The method for producing a functional substrate according to claim 1, further comprising a pretreatment step of performing at least one of mechanical milling, jet milling, and electroless plating as a pretreatment for the compound.

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