JP2017218584A - Production method of sulfur-modified polyacrylonitrile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method of sulfur-modified polyacrylonitrile capable of realizing a secondary battery having high electric capacity by using as an active material of a secondary battery electrode.SOLUTION: A production method of sulfur-modified polyacrylonitrile, which uses a drop type powder treatment device that includes: a raw material feeding part for feeding a powder of a raw material containing a polyacrylonitrile powder and a sulfur powder; a heating part for heating the powder that is supplied from the raw material feeding part and falls; and a cooling part for cooling the heated powder, in which the drop speed of the powder dropping inside of the heating part is controlled by supplying a gas from a lower side and/or an upper side of the heating part.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for producing sulfur-modified polyacrylonitrile and uses of sulfur-modified polyacrylonitrile obtained by the production method.

  With the spread of portable electronic devices such as portable personal computers, handy video cameras and information terminals in recent years, non-aqueous electrolyte secondary batteries having high voltage and high energy density have been widely used as power sources. Also, from the viewpoint of environmental problems, battery cars and hybrid cars using electric power as a part of power have been put into practical use.

  The characteristics of the nonaqueous electrolyte secondary battery depend on its constituent members such as electrodes, separators, electrolytes, and the like, and research and development of each constituent member is actively performed. In an electrode, an electrode active material is important together with a binder, a current collector, and the like, and research and development of the electrode active material is actively performed.

  In recent years, research has been conducted on the use of sulfur, which is a substance having the theoretically maximum electric capacity among known materials, as an electrode active material. For example, Patent Document 1 proposes using sulfur-modified polyacrylonitrile as an active material for a secondary battery. The sulfur-modified polyacrylonitrile is obtained by heat-treating a mixture of polyacrylonitrile powder and sulfur powder in a non-oxidizing atmosphere. Patent Document 1 discloses that sulfur-modified polyacrylonitrile is produced by heating a mixture of sulfur powder and polyacrylonitrile powder in a non-oxidizing atmosphere while refluxing sulfur vapor while preventing outflow of sulfur vapor. Have been described.

  As described above, sulfur-modified polyacrylonitrile is obtained by heat-treating a mixture of polyacrylonitrile powder and sulfur powder. As a device for heat-treating powder, Patent Document 2 describes a drop-type powder treatment device. Has been. The drop-type powder processing apparatus described in Patent Document 2 includes a raw material supply unit 30 that supplies a raw material powder W, a heating unit 40 that heats the powder W that is supplied from the raw material supply unit 30 and falls, And a cooling unit 50 for cooling the heat-treated powder W. The drop-type powder processing apparatus described in Patent Document 2 controls the falling speed of the powder falling in the heating unit 40 by supplying gas from the lower side and / or the upper side of the heating unit 40. The drop-type powder processing apparatus described in Patent Document 2 is supplied from the lower side and / or the upper side of the heating unit 40 according to the type, specific gravity, particle size, and the like of the powder W falling in the heating unit 40. By adjusting the gas supply amount, the falling speed of the powder W can be controlled. Therefore, even when the type, specific gravity, particle size, etc. of the powder W are different, the time for heating the powder W can be reduced. It can be adjusted easily and appropriately.

International Publication No. 2010/044437 JP 2012-228631 A

  However, the production method described in Patent Document 1 is not economical because the obtained sulfur-modified polyacrylonitrile contains a sulfur solid, and thus a heat treatment step for removing the sulfur solid from the sulfur-modified polyacrylonitrile is further required. Further, since the average particle diameter of the obtained sulfur-modified polyacrylonitrile varies greatly, it was not fully satisfactory as an active material for an electrode of a secondary battery. Accordingly, there has been a demand for a method for producing sulfur-modified polyacrylonite having sufficiently satisfactory characteristics as an active material for an electrode of a secondary battery.

  Patent Document 2 does not describe the use of a drop-type powder processing apparatus for the production of sulfur-modified polyacrylonitrile.

  Accordingly, an object of the present invention is to provide a production method for obtaining a high-quality sulfur-modified polyacrylonitrile. Moreover, the manufacturing method of the electrode for secondary batteries using the sulfur modified polyacrylonitrile obtained by the manufacturing method of this invention is provided.

  As a result of intensive studies, the present inventors have found that a high-quality sulfur-modified polyacrylonitrile can be efficiently produced by using a dropping powder processing apparatus, and have completed the present invention.

The present invention includes a raw material supply unit that supplies a raw material powder containing polyacrylonitrile powder and sulfur powder, a heating unit that heats and drops the powder supplied from the raw material supply unit, and the heat-treated powder A method for producing sulfur-modified polyacrylonitrile using a drop-type powder processing apparatus provided with a cooling unit for cooling the body,
The present invention provides a method for producing sulfur-modified polyacrylonitrile, which comprises a step of supplying a gas from the lower side and / or the upper side of the heating unit to control the falling speed of the powder falling in the heating unit.

  Further, the present invention provides the falling powder, comprising an exhaust gas part for exhausting the exhaust gas in the heating part to the outside above the heating part, wherein the exhaust gas part is provided with an exhaust gas treatment device for detoxifying the exhaust gas. The present invention provides a method for producing the above-mentioned sulfur-modified polyacrylonitrile using a processing apparatus.

  Further, the present invention uses the dropping powder processing apparatus having a mechanism for controlling a falling speed of the powder falling in the heating unit by a gas supplied from the lower side and / or the upper side of the heating unit, A method for producing sulfur-modified polyacrylonitrile is provided.

  Further, the present invention provides the exhaust gas unit having a pressure measuring device for measuring the pressure in the heating unit, and the gas introduced into the heating unit according to the pressure in the heating unit measured by the pressure measuring device. The present invention provides a method for producing the sulfur-modified polyacrylonitrile using the dropping powder processing apparatus having a control device for adjusting the amount.

  Moreover, this invention provides the manufacturing method of the above-mentioned sulfur modified polyacrylonitrile in which the said raw material contains a conductive support agent further.

  Moreover, this invention provides the manufacturing method of the electrode for secondary batteries which has the process of manufacturing sulfur modification polyacrylonitrile by the manufacturing method of the above-mentioned sulfur modification polyacrylonitrile.

  Moreover, this invention provides the manufacturing method of a secondary battery which has the process of manufacturing the electrode for secondary batteries with the manufacturing method of the electrode for secondary batteries mentioned above.

  In the production method of the present invention, since the obtained sulfur-modified polyacrylonitrile does not contain sulfur solids, there is no need for a heat treatment step for removing sulfur solids from the obtained sulfur-modified polyacrylonitrile. Since there is little adhesion of acrylonitrile, the recovery rate of sulfur-modified polyacrylonitrile is high and maintenance is easy, which is economical. In addition, since the sulfur-modified polyacrylonitrile obtained by the production method of the present invention has a small particle size and is homogeneous, it can be used as an active material for a secondary battery electrode. A secondary battery with a capacity retention rate can be realized.

FIG. 1 is a longitudinal sectional view schematically showing an example of a drop type powder processing apparatus used in the method for producing sulfur-modified polyacrylonitrile of the present invention. FIG. 2 is a longitudinal sectional view schematically showing an example of the structure of a coin-type battery of a secondary battery having an electrode containing sulfur-modified polyacrylonitrile obtained by the production method of the present invention. FIG. 3 is a schematic view showing a basic configuration of a cylindrical battery of a secondary battery having an electrode containing sulfur-modified polyacrylonitrile obtained by the production method of the present invention. FIG. 4 is a perspective view showing in cross section the internal structure of a cylindrical battery of a secondary battery having an electrode containing sulfur-modified polyacrylonitrile obtained by the production method of the present invention.

  A method for producing the sulfur-modified polyacrylonitrile of the present invention will be described.

  First, the raw material used in the method for producing the sulfur-modified polyacrylonitrile of the present invention contains polyacrylonitrile and sulfur, and may contain other materials.

  The raw material powder used in the production method of the present invention contains polyacrylonitrile powder. The average particle size of the polyacrylonitrile powder is preferably 1 to 150 μm, more preferably 1 to 50 μm. When the average particle diameter of the polyacrylonitrile powder is smaller than 1 μm, the polyacrylonitrile powder is not dropped in the drop-type powder processing apparatus and is discharged together with the exhaust gas, which is not preferable. If it is larger than 150 μm, there is a possibility that the quality may be lowered by passing through the heating part before the reaction is completed, and the productivity may be lowered due to a longer reaction time. In addition, when the weight average molecular weight of the polyacrylonitrile powder is low, it is difficult to obtain the polyacrylonitrile powder. When the weight average molecular weight is too large, the bound sulfur content is difficult to increase, so that the range is from 10,000 to 1,000,000. A thing in the range of about 10,000-300,000 is more preferable. In addition, the measured value converted into polystyrene by GPC (gel permeation chromatography) method is used for the weight average molecular weight. In the present invention, the bound sulfur means sulfur existing in a chemical bond with the modified polyacrylonitrile.

  The raw material powder used in the production method of the present invention contains sulfur powder. The average particle diameter of the sulfur powder is preferably in the range of 1 to 100 μm, and preferably in the range of 1 to 50 μm. The reason why the average particle size of the sulfur powder is within the above range is the same as the reason why the average particle size of the polyacrylonitrile powder is within the above range. The content of sulfur powder in the raw material used in the production method of the present invention is such that when the sulfur powder ratio to the polyacrylonitrile powder is small, the bound sulfur content of the sulfur-modified polyacrylonitrile is small, and the sulfur powder ratio to the polyacrylonitrile powder is large. Therefore, the amount of solid sulfur that is unreacted and needs to be recovered increases, and therefore, preferably 100 to 500 parts by mass, more preferably 200 to 400 parts by mass with respect to 100 parts by mass of the polyacrylonitrile powder. And

  The raw material powder used in the production method of the present invention may contain other materials. Examples of the material other than the above include materials used as conductive aids for secondary battery electrodes. Specific examples include carbon materials, metal powders, and conductive metal oxides. Carbon materials include natural graphite, artificial graphite, carbon black, ketjen black, channel black, furnace black, lamp black, thermal black, carbon nanotubes, graphene, needle coke, etc., and metal powders include aluminum powder, nickel Examples of the conductive metal oxide include zinc oxide and titanium oxide. The other materials are preferably powdery. The other materials preferably have an average particle size of 0.01 to 50 μm, and more preferably 0.1 to 20 μm. The content of the other materials in the raw material used in the production method of the present invention is preferably 1 to 30 parts by mass, more preferably 1 to 10 parts by mass with respect to 100 parts by mass of the polyacrylonitrile powder.

  The average particle size of the polyacrylonitrile powder, sulfur powder, and other material powders contained in the raw material used in the production method of the present invention can be measured by, for example, a laser diffraction / scattering method.

  Next, an apparatus for producing sulfur-modified polyacrylonitrile that is preferably used in the production method of the present invention will be described. 1 is a drop-type powder processing apparatus, and is supplied from a raw material supply unit 30 that supplies raw material powder W and a raw material supply unit 30. The manufacturing apparatus illustrated in FIG. A cylindrical heating unit 40 that heat-processes the powder W that is dropped, a cooling unit 50 that cools the heat-treated powder W, a gas supply device 60 that supplies an inert gas to the heating unit 40, and heating The exhaust gas part 70 which discharges | emits the exhaust gas in the part 40 outside is provided. The manufacturing apparatus shown in FIG. 1 controls the drop speed of the powder W that falls in the heating unit 40 by supplying gas from the lower side and / or the upper side of the heating unit 40.

  As shown in FIG. 1, the raw material supply unit 30 includes a raw material supply device 31, a sieving device 32, and a guide tube 33. The raw material supply device 31 supplies the raw material to be heated to the heating unit 40. The sieving device 32 is located below the raw material supply device 31 in the vertical direction X, and screens the agglomerated powder W guided from the raw material supply device 31 to adjust the average particle diameter of the powder W. To do. The guide tube 33 is located immediately below the sieving device 32 in the vertical direction X, and is inserted into the heating unit 40 to guide the powder W dispersed by the sieving device 32 to the cylindrical heating unit 40. In addition, what was sifted beforehand can be used for a raw material.

  As shown in FIG. 1, the heating unit 40 is located immediately below the guide tube 33 in the vertical direction X. The heating unit 40 is heated by the heating device 41 disposed on the outer peripheral side of the heating unit 40, and heats the powder W falling in the heating unit 40. The heating unit 40 has an extending part 40 </ b> A that hangs vertically downward from the lower end of the heat insulating material D, and the extending part 40 </ b> A is inserted into the cooling unit 50.

  The cooling unit 50 is located immediately below the heating unit 40 in the vertical direction X. The cooling unit 50 includes an umbrella-shaped guide member 51 therein. The guide member 51 is in contact with the powder W that has been guided from the heating unit 40 to the cooling unit 50 and is heat-treated in the heating unit 40, and cools the powder W. Lead to the wall. The powder W guided to the inner wall surface of the cooling unit 50 by the guide member 51 is cooled by contacting the inner wall surface of the cooling unit 50. The cooling unit 50 may not have the guide member 51.

  The gas supply device 60 supplies an inert gas such as nitrogen or argon to the heating unit 40. As shown in FIG. 1, the gas supply device 60 includes a first supply path 61a and a second supply path 61b. The first supply path 61 a communicates with the cooling unit 50 and guides the inert gas supplied from the gas supply device 60 into the cooling unit 50. The inert gas introduced into the cooling unit 50 through the first supply path 61a is introduced into the heating unit 40 from directly below the heating unit 40 in the vertical direction X. The second supply path 61 b communicates with the raw material supply unit 30 and guides the inert gas supplied from the gas supply device 60 into the raw material supply unit 30. The inert gas guided by the second supply path 61 b is dispersed by the sieving device 32 and sends the powder W guided to the guide tube 33 into the heating unit 40.

  Further, the gas supply device 60 includes a first flow rate adjustment valve 62a disposed in the first supply path 61a, a second flow rate adjustment valve 62b disposed in the second supply path 61b, the first flow rate adjustment valve 62a and the first flow rate adjustment valve 62a. 2 and a control device 63 for controlling the flow rate adjusting valve 62b. The control device 63 controls the first flow rate adjustment valve 62a, adjusts the amount of inert gas introduced from the cooling unit 50 into the heating unit 40 through the first supply path 61a, and controls the second flow rate adjustment valve 62b. The amount of the inert gas guided to the guide pipe 33 in the raw material supply unit 30 through the second supply path 61b is adjusted.

  The exhaust gas unit 70 is disposed on the upper side of the heating unit 40 in the vertical direction X. The exhaust gas unit 70 includes an exhaust gas treatment device 71 that removes harmful components contained in the exhaust gas and renders the exhaust gas harmless.

Further, the exhaust gas unit 70 is provided with a pressure measuring device 72 for measuring the pressure in the heating unit 40. The pressure measuring device 72 measures the pressure in the heating unit 40 and outputs the measured pressure in the heating unit 40 to the control device 63. The control device 63 controls the first flow rate adjusting valve 62a in accordance with the pressure of the heating unit 40 output from the pressure measuring device 72, and enters the heating unit 40 from the cooling unit 50 through the first supply path 61a. The amount of inert gas introduced is adjusted, and the control device 63 controls the second flow rate adjustment valve 62b to adjust the amount of gas introduced to the guide pipe 33 in the raw material supply unit 30 through the second supply path 61b. To do.
Here, although it is very difficult to actually measure the dropping speed and dropping time of the powder W in the heating unit 40 during heating, the control device is based on the pressure in the heating unit 40 as described above. By adjusting the amount of gas introduced into the heating unit 40 from the cooling unit 50 or the guide tube 33 by 63, the manufacturing apparatus 10A can adjust or reproduce the heat treatment condition of the powder W.

  Moreover, it is preferable to provide the heat insulating material D around the heating unit 40 and the exhaust gas unit 70 in the manufacturing apparatus 10A.

  In the case where the manufacturing apparatus 10A heats the powder W and wants to increase the time during which the powder W is heat-treated in the heating unit 40, the control device 63 causes the first flow rate adjustment valve 62a and the second flow rate adjustment valve to be processed. 62b is controlled to increase the amount of inert gas introduced from the cooling section 50 into the heating section 40 through the first supply path 61a, while being guided to the guide pipe 33 in the raw material supply section 30 through the second supply path 61b. The amount of the inert gas to be burned is reduced, or the gas is not led to the guide tube 33 in the raw material supply unit 30. According to the manufacturing apparatus 10A having such a configuration, even if the powder W has a large specific gravity and a large particle size and has a fast free-falling speed in the heating unit 40, the heating unit 40 is heated from the cooling unit 50. It is possible to slow down the falling speed by the gas guided into the inside, and as a result, it is possible to lengthen the time for heating the powder W in the heating unit 40. In addition, when the powder W having a slow free fall speed is used, it is possible to reduce the fall speed of the powder W.

  Further, when the manufacturing apparatus 10A wants to shorten the time for the heat treatment in the heating unit 40 of the powder W when the powder W is heat-treated, the control device 63 causes the first flow rate adjustment valve 62a and the second flow rate to be reduced. The control valve 62b is controlled to reduce the amount of inert gas introduced from the cooling unit 50 into the heating unit 40 through the first supply path 61a, or the inert gas is supplied from the cooling unit 50 into the heating unit 40. On the other hand, the amount of the inert gas guided to the guide pipe 33 in the raw material supply unit 30 through the second supply path 61b is increased. According to the manufacturing apparatus 10A having such a configuration, even with the powder W having a small specific gravity and a small particle size and a slow free-falling speed in the heating unit 40, the inert gas guided to the guide tube 33 In addition, it is possible to increase the falling speed in the heating unit 40, and as a result, it is possible to shorten the time for the heat treatment of the powder W in the heating unit 40. In addition, when the powder W having a high free fall speed is used, it is possible to further increase the fall speed of the powder W.

  That is, the manufacturing apparatus 10 </ b> A has a mechanism for controlling the falling speed of the powder W falling in the heating unit 40 by the gas supplied from the lower side and / or the upper side of the heating unit 40.

  Next, the process for producing the sulfur-modified polyacrylonitrile of the present invention will be described step by step. The production method of the present invention can be preferably carried out, for example, by using a sulfur-modified polyacrylonitrile production apparatus 10A shown in FIG.

  In the manufacturing method of the present invention, first, the raw material powder W to be heat-treated is guided to the sieving device 32 from the raw material supplying device 31 provided in the raw material supplying unit 30 of the manufacturing apparatus 10A, and is aggregated by the sieving device 32. The powder W that has been screened is screened to adjust the average particle size of the powder W. In the production method of the present invention, the powder W is pulverized so that the average particle diameter is preferably 1 to 100 μm, more preferably 1 to 50 μm.

  Then, the powder W dispersed by the sieving device 32 is introduced into the cylindrical heating unit 40 through the guide tube 33 in the raw material supply unit 30 and dropped in the heating unit 40.

  In the manufacturing method of the present invention, the inside of the heating unit 40 is heated by the heating device 41 provided on the outer peripheral side of the heating unit 40 of the manufacturing apparatus 10A, and the powder W falling in the heating unit 40 is heat-treated.

  In the manufacturing method of the present invention, when the powder W is heat-treated in the heating unit 40, the inert gas such as nitrogen or argon is supplied from the gas supply device 60 of the manufacturing apparatus 10A through the first supply path 61a. The gas is introduced into the cooling unit 50, the inert gas introduced into the cooling unit 50 is introduced into the heating unit 40 from the lower side in the vertical direction of the heating unit 40, and the inert gas is supplied from the gas supply device 60 to the second supply. The powder W guided to the raw material supply unit 30 through the path 61b and dispersed by the sieving device 32 and guided to the guide tube 33 is sent out into the heating unit 40 by this inert gas.

  Further, in the manufacturing method of the present invention, the control device 63 controls the first flow rate adjustment valve 62a provided in the first supply path 61a and the second flow rate adjustment valve 62b provided in the second supply path 61b. The amount of gas guided from the cooling unit 50 to the heating unit 40 through the first supply path 61a is adjusted, and the amount of gas guided to the guide pipe 33 in the raw material supply unit 30 through the second supply path 61b is adjusted. adjust.

  Specifically, in the manufacturing method of the present invention, the pressure in the heating unit 40 measured by the pressure measuring device 72 is output to the control device 63, and the first control device 63 outputs the first pressure according to the pressure of the heating unit 40. Control the flow rate adjustment valve 62a, adjust the amount of gas guided from the cooling unit 50 to the heating unit 40 through the first supply path 61a, and control the second flow rate adjustment valve 62b by the control device 63, The amount of gas guided to the guide pipe 33 in the raw material supply unit 30 through the second supply path 61b is adjusted.

  Here, it is very difficult to actually measure the dropping speed and dropping time of the powder W during heating. However, in the manufacturing method of the present invention, the control device 63 adjusts the amount of gas introduced into the heating unit 40 from the cooling unit 50 or the guide tube 33 based on the pressure in the heating unit 40, thereby reducing the powder. It enables adjustment and reproduction of the heat treatment conditions of the body W.

  In the manufacturing method of the present invention, when the time for heat treatment in the heating unit 40 of the powder W is increased when the powder W is heat-treated, the controller 63 controls the first flow rate adjusting valve 62a and the second flow rate. The flow control valve 62b is controlled to increase the amount of inert gas introduced from the cooling unit 50 into the heating unit 40 through the first supply path 61a, while the guide pipe in the raw material supply unit 30 through the second supply path 61b. The amount of the inert gas guided to 33 is reduced, or the inert gas is not guided to the guide tube 33 in the raw material supply unit 30. In the production method of the present invention, by controlling the supply amount of the inert gas supplied to the heating unit 40 as described above, the specific gravity and particle size are large, and the speed of free fall in the heating unit 40 is fast. Even in the case of the body W, the falling speed of the inert gas guided from the cooling unit 50 into the heating unit 40 is reduced, and the time for heating the powder W in the heating unit 40 can be extended. In addition, when the powder W having a slow free fall speed is used, the fall speed of the powder W can be further reduced.

  On the other hand, when shortening the heat treatment time in the heating unit 40 of the powder W, the control device 63 controls the first flow rate adjustment valve 62a and the second flow rate adjustment valve 62b, and passes through the first supply path 61a. The amount of gas guided from the cooling unit 50 into the heating unit 40 is reduced, or the inert gas is not guided from the cooling unit 50 into the heating unit 40, while the raw material supply unit passes through the second supply path 61 b. The amount of gas guided to the guide tube 33 at 30 is increased. In the production method of the present invention, by controlling the supply amount of the inert gas supplied to the heating unit 40 as described above, the specific gravity and the particle size are small, and the speed of free fall in the heating unit 40 is slow. Even in the case of the body W, the inert gas guided to the guide tube 33 increases the speed of dropping in the heating unit 40, and the time for heating the powder W in the heating unit 40 can be shortened. In addition, when the powder W having a fast free fall speed is used, the fall speed of the powder W can be further increased.

  In the manufacturing method of the present invention, the temperature in the heating unit 40 is usually 300 to 1000 ° C., preferably 400 to 700 ° C., and the amount of gas supplied from the first supply path 61a and the second supply path 61b. It is preferable to adjust the amount of the supplied gas so that the powder W falls in the heating unit 40 at a rate of heating for 1 to 120 seconds, particularly 5 to 60 seconds.

  And in the manufacturing method of this invention, the heat-processed powder W which falls is guide | induced from the inside of the heating part 40 in the cooling part 50 provided in the perpendicular direction lower part of the heating part 40, and is cooled. In the manufacturing method of this invention, in the cooling part 50, it is preferable to cool the powder W to 10-100 degreeC, and it is more preferable to cool to 20-50 degreeC.

  Specifically, in the manufacturing method of the present invention, the powder W falling in the cooling unit 50 is brought into contact with the umbrella-shaped guide member 51 provided in the cooling unit 50 to cool the guide member 51. Thus, the powder W is guided to the inner wall surface of the cooling unit 50, and the powder W is efficiently cooled by contact with the inner wall surface.

  In the manufacturing method of the present invention, the exhaust gas generated in the heating unit 40 is taken into the exhaust gas unit 70 and rendered harmless by the exhaust gas processing device 71, and then discharged to the outside by the exhaust gas unit 70.

  The sulfur-modified polyacrylonitrile obtained by the production method of the present invention has characteristics that it does not contain a sulfur solid, has a small particle size and is homogeneous, and is useful as an active material for a secondary battery electrode. In the present invention, the sulfur solid means sulfur which is not chemically bonded to the modified polyacrylonitrile and exists as a simple substance. Specifically, the sulfur-modified polyacrylonitrile obtained by the production method of the present invention preferably has an average particle size of 1 to 100 μm, and more preferably 1 to 50 μm. The average particle diameter of sulfur-modified polyacrylonitrile can be measured by a laser diffraction / scattering method. Moreover, that sulfur-modified polyacrylonitrile does not contain sulfur solid means that the content of sulfur solid in sulfur-modified polyacrylonitrile is less than 5% by mass, preferably less than 2% by mass, more preferably 0% by mass. In addition, the content of bound sulfur in the sulfur-modified polyacrylonitrile is preferably 25 to 60% by mass, and more preferably 30 to 55% by mass. The content of sulfur solid and bound sulfur in the sulfur-modified polyacrylonitrile can be measured by thermogravimetry and elemental analysis. In addition, below, the process of manufacturing the electrode for secondary batteries by the manufacturing method of the electrode for secondary batteries which has the process of manufacturing sulfur modification polyacrylonitrile by the manufacturing method of this invention, and this electrode for secondary batteries A method for manufacturing a secondary battery having the above will be described. The sulfur-modified polyacrylonitrile obtained by the production method of the present invention can be used for both active materials of the positive electrode and the negative electrode. When the sulfur-modified polyacrylonitrile obtained by the production method of the present invention is used as a negative electrode active material, a positive electrode active material that is normally used as a positive electrode active material of a lithium secondary battery or a lithium ion secondary battery may be used. it can. In addition, when the sulfur-modified polyacrylonitrile obtained by the production method of the present invention is used as a positive electrode active material, a negative electrode active material that is usually used as a negative electrode active material of a lithium secondary battery or a lithium ion secondary battery is used. be able to.

The electrode for a secondary battery is manufactured by the following steps (1) to (3).
(1) Step of mixing electrode mixture containing electrode active material containing sulfur-modified polyacrylonitrile obtained by the production method of the present invention to form a slurry (2) Slurry electrode mixture (3) The step of heating the current collector after application of the electrode mixture

In the following, the steps (1) to (3) will be described in more detail.
(1) Step of mixing an electrode active material containing sulfur-modified polyacrylonitrile obtained by the production method of the present invention and an electrode mixture containing a binder into a slurry state Electrode containing an electrode active material and a binder In the mixture, a known material can be used except that the sulfur-modified polyacrylonitrile obtained by the production method of the present invention is used as the electrode active material. In addition to the electrode active material and the binder, other components (a binder, a conductive additive, a lithium salt, a polymerization initiator, a filler, a solvent, and the like) can be added to the electrode mixture.

The amount of each component contained in the electrode mixture is not particularly limited and can be adjusted based on a conventionally known technique for the active material layer of the battery, but is preferably as follows.
The content of sulfur-modified polyacrylonitrile in the electrode mixture is usually 10 to 99.9% by mass in the electrode mixture.
The binder is preferably 0.1 to 10 parts by mass, and more preferably 0.5 to 5 parts by mass with respect to 100 parts by mass of the electrode active material.

  The method of mixing the electrode mixture to form a slurry is not particularly limited, but a normal dispersing machine such as a ball mill or a sand mill, an ultrasonic dispersing machine, a homogenizer, or the like can be used.

(2) Step of applying slurry-like electrode mixture to current collector As a method of applying slurry-like electrode mixture to current collector, for example, a die coater method, a curtain coater method, a spray coater method, Various methods such as a gravure coater method, a flexo coater method, a knife coater method, a doctor blade method, and a reverse roll method can be used. In the coating process, a plurality of coating methods may be used in combination. In the present invention, the density of the active material present on the current collector is preferably 1 g · cm ^{−3 to} 2.2 g · cm ⁻³ , more preferably 1.3 g · cm ⁻³ to 1. 9 g · cm ⁻³ .

(3) Step of heating and drying current collector after application of electrode mixture The temperature at which the electrode mixture applied on the current collector is heated is usually 80 to 180 ° C. The heating conditions such as the heating time can be appropriately set according to the application amount of the electrode mixture and the volatilization rate. This heating is for volatilizing and drying the solvent in the electrode mixture. When the binder is polymerized by heating, a thermal polymerization initiator can be included in the electrode mixture. When the electrode mixture does not contain a solvent, energy rays such as ultraviolet light may be irradiated without heating in order to polymerize the binder. In this case, it is preferable to include a photopolymerization initiator in the electrode mixture.

  Moreover, the manufacturing process of the electrode of this invention can also press-process the electrode which consists of a coating film and a collector on arbitrary conditions following the above-mentioned operation.

  Hereinafter, each member used in the electrode manufacturing process will be described in more detail.

<Binder>
A well-known thing can be used for the binder used by this invention. Specific examples of the binder include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), ethylene-propylene-diene copolymer (EPDM), styrene-butadiene rubber (SBR), and acrylonitrile butadiene rubber (NBR). , Styrene-isoprene copolymer, polymethyl methacrylate, polyacrylate, polyvinyl alcohol (PVA), carboxymethyl cellulose (CMC), methyl cellulose (MC), starch, polyvinyl pyrrolidone, polyethylene (PE), polypropylene (PP), polyimide (PI ) And polyacrylic acid.

<Conductive aid>
Examples of the conductive assistant used in the present invention include natural graphite, artificial graphite, carbon black, ketjen black, channel black, furnace black, lamp black, thermal black, carbon nanotube, graphene, needle coke, and other carbon materials; aluminum powder, Metal powder such as nickel powder; conductive metal oxide such as zinc oxide and titanium oxide. As described in the above production method, this conductive auxiliary agent can also be mixed during the production of sulfur-modified polyacrylonitrile. The content of the conductive additive in the electrode mixture is usually 0.01 to 50 parts by mass with respect to 100 parts by mass of the electrode active material.

<Lithium salt>
The lithium salt used in the present _{invention, LiClO 4, LiPF 6, LiBF} 4, LiCF 3 SO 3, LiSbF 6, LiAsF 6, LiAlCl 4, LiN (CF 3 SO 3) 2, LiC (CF 3 SO 3) 3, _{LiC 4 F 4 SO 3, Li} (C 2 F 5 SO 2) 2 N and the like.

<Polymerization initiator>
The polymerization initiator used in the present invention is a thermal polymerization initiator or a photopolymerization initiator. Examples of the thermal polymerization initiator include AIBN, sodium persulfate, potassium persulfate, ammonium persulfate, lauroyl peroxide, di- Examples of photopolymerization initiators include α-carbonyl compounds, acyloin ethers, acyloin compounds, polynuclear quinone compounds, triarylimidazoles, such as 2-ethylhexyl peroxydicarbonate, diisopropylbenzene hydroperoxide, cumene hydroperoxide, and the like. Dimer / p-aminophenyl ketone combinations, acridine and phenazine compounds, oxadiazole compounds, and the like.

<Filler>
Examples of the filler used in the present invention include olefin polymers such as polyethylene and polypropylene; fiber materials such as glass fiber and carbon fiber; zeolite;

<Solvent>
Examples of the solvent used in the present invention include propylene carbonate, ethylene carbonate, diethyl carbonate, dimethyl carbonate, ethyl methyl carbonate, 1,2-dimethoxyethane, 1,2-diethoxyethane, acetonitrile, propionitrile, tetrahydrofuran, 2- Methyltetrahydrofuran, dioxane, 1,3-dioxolane, nitromethane, N-methylpyrrolidone, N, N-dimethylformamide, dimethylacetamide, methylethylketone, cyclohexanone, methyl acetate, methyl acrylate, diethyltriamine, N, N-dimethylaminopropylamine Polyethylene oxide, tetrahydrofuran, dimethyl sulfoxide, sulfolane, γ-butyrolactone water, alcohol and the like. 30-300 mass parts is preferable with respect to 100 mass parts of electrode active materials, and, as for the usage-amount of a solvent, 50-200 mass parts is still more preferable.

<Current collector>
As the current collector, a conductive material such as titanium, titanium alloy, aluminum, aluminum alloy, copper, nickel, stainless steel, nickel-plated steel, or the like is used. Examples of the shape of the current collector include a foil shape, a plate shape, and a net shape, and the current collector may be either porous or non-porous. In addition, these conductive materials may be subjected to a surface treatment in order to improve adhesion and electrical characteristics. The thickness of the current collector is not particularly limited, but is usually 1 to 100 μm.

  The secondary battery electrode produced by the production method of the present invention is usually used as an electrode for a nonaqueous electrolyte secondary battery, for example, but can also be used as an electrode for a primary battery. Examples of the nonaqueous electrolyte secondary battery include, but are not limited to, a lithium secondary battery and a lithium ion secondary battery.

  Next, the manufacturing method of the secondary battery of the present invention using the electrode manufactured by the manufacturing method of the present invention will be described in detail based on preferred embodiments. Specifically, the nonaqueous electrolyte, the separator, and the exterior member excluding the electrodes constituting the nonaqueous electrolyte secondary battery will be described. In the secondary battery manufacturing method of the present invention, the secondary battery electrode, non-aqueous electrolyte, separator, and exterior member obtained by the secondary battery electrode manufacturing method of the present invention are assembled by a known method. The shape of the secondary battery is not particularly limited, and examples thereof include a coin-type secondary battery, a cylindrical secondary battery, a prismatic secondary battery, and a stacked secondary battery.

<Counter electrode>
The electrode for secondary batteries manufactured by the manufacturing method of this invention can be used as a positive electrode, and can also be used as a negative electrode. When the secondary battery electrode manufactured by the manufacturing method of the present invention is used as a positive electrode of a lithium ion secondary battery, an electrode having a known negative electrode active material can be used as a negative electrode. When the secondary battery electrode produced by the production method of the present invention is used as a negative electrode of a lithium ion secondary battery, an electrode having a known positive electrode active material may be used as the positive electrode.

Known negative electrode active materials include natural graphite, artificial graphite, non-graphitizable carbon, graphitizable carbon, lithium, lithium alloy, tin alloy, silicon alloy, silicon oxide, silicon, titanium oxide, iron oxide, manganese oxide, and oxidation. In addition to cobalt, nickel oxide, lead oxide, ruthenium oxide, tungsten oxide, and zinc oxide, composite oxides such as LiVO ₂ , Li ₂ VO ₄ , and Li ₄ Ti ₅ O ₁₂ can be given.

Examples of known positive electrode active materials include lithium transition metal composite oxides, lithium-containing transition metal phosphate compounds, and the like, and these may be used in combination. As the transition metal of the lithium transition metal composite oxide, vanadium, titanium, chromium, manganese, iron, cobalt, nickel, copper and the like are preferable. Specific examples of the lithium transition metal composite oxide include lithium cobalt composite oxide such as LiCoO ₂ , lithium nickel composite oxide such as LiNiO ₂ , and lithium manganese composite oxide such as LiMnO ₂ , LiMn ₂ O ₄ , and Li ₂ MnO _3. Some of the transition metal atoms that are the main components of these lithium transition metal composite oxides are aluminum, titanium, vanadium, chromium, manganese, iron, cobalt, lithium, nickel, copper, zinc, magnesium, gallium, zirconium, etc. The thing substituted with the other metal etc. are mentioned. As specific examples of the substituted ones, for example, Li _1.1 Mn _1.8 Mg _0.1 O ₄ , Li _1.1 Mn _1.85 Al _0.05 O ₄ , LiNi _0.5 Co _0.2 Mn _{0.3 O 2, LiNi 0.5 Mn 0.5} O 2, LiNi 0.80 Co 0.17 Al 0.03 O 2, LiNi 1/3 Co 1/3 Mn 1/3 O 2, LiMn 1. ₈ Al _0.2 O ₄ , LiMn _1.5 Ni _0.5 O _{4 and the} like. As the transition metal of the lithium-containing transition metal phosphate compound, vanadium, titanium, manganese, iron, cobalt, nickel, and the like are preferable. Specific examples include iron phosphates such as LiFePO ₄ and phosphorus such as LiCoPO _4. Cobalt acids, some of the transition metal atoms that are the main components of these lithium transition metal phosphate compounds are aluminum, titanium, vanadium, chromium, manganese, iron, cobalt, lithium, nickel, copper, zinc, magnesium, gallium, zirconium And those substituted with other metals such as niobium.

<Nonaqueous electrolyte>
Examples of the non-aqueous electrolyte include a liquid non-aqueous electrolyte prepared by dissolving an electrolyte in an organic solvent, and a gel non-aqueous electrolyte obtained by combining a liquid electrolyte and a polymer material.

As an electrolyte used for the preparation of the liquid non-aqueous electrolyte, for example, a conventionally known lithium salt is used. For example, LiPF ₆ , LiBF ₄ , LiAsF ₆ , LiCF ₃ SO ₃ , LiCF ₃ CO ₂ , LiN (CF ₃ SO ₂ ) ₂ , LiC (CF ₃ SO ₂ ) ₃ , LiB (CF ₃ SO ₃ ) ₄ , LiB (C ₂ O ₄ ) ₂ , LiBF ₂ (C ₂ O ₄ ), LiSbF ₆ , LiSiF ₅ , LiAlF ₄ , LiSCN, Examples include LiClO ₄ , LiCl, LiF, LiBr, LiI, LiAlF ₄ , LiAlCl ₄ , and derivatives thereof. Among these, LiPF ₆ , LiBF ₄ , LiClO ₄ , LiAsF ₆ , LiCF ₃ SO ₃ , and LiC ( CF ₃ SO ₂ ) ₃ and derivatives of LiCF ₃ SO ₃ , and LiC (C It is preferable to use one or more selected from the group consisting of derivatives of F ₃ SO ₂ ) ₃ .

  As the organic solvent used for the preparation of the liquid non-aqueous electrolyte used in the present invention, those usually used for non-aqueous electrolytes can be used alone or in combination of two or more. Specific examples include saturated cyclic carbonate compounds, saturated cyclic ester compounds, sulfoxide compounds, sulfone compounds, amide compounds, saturated chain carbonate compounds, chain ether compounds, cyclic ether compounds, and saturated chain ester compounds.

Among the above organic solvents, saturated cyclic carbonate compounds, saturated cyclic ester compounds, sulfoxide compounds, sulfone compounds and amide compounds have a high relative dielectric constant, and thus serve to increase the dielectric constant of non-aqueous electrolytes, particularly saturated cyclic carbonate compounds. Is preferred. Examples of such saturated cyclic carbonate compounds include ethylene carbonate, 1,2-propylene carbonate, 1,3-propylene carbonate, 1,2-butylene carbonate, 1,3-butylene carbonate, 1,1, -dimethylethylene carbonate. Etc. Examples of the saturated cyclic ester compound include γ-butyrolactone, γ-valerolactone, γ-caprolactone, δ-hexanolactone, and δ-octanolactone. Examples of the sulfoxide compound include dimethyl sulfoxide, diethyl sulfoxide, dipropyl sulfoxide, diphenyl sulfoxide, thiophene, and the like. Examples of the sulfone compounds include dimethyl sulfone, diethyl sulfone, dipropyl sulfone, diphenyl sulfone, sulfolane (also referred to as tetramethylene sulfone), 3-methyl sulfolane, 3,4-dimethyl sulfolane, 3,4-diphenimethyl sulfolane, sulfolene. , 3-methylsulfolene, 3-ethylsulfolene, 3-bromomethylsulfolene and the like, and sulfolane and tetramethylsulfolane are preferable. Examples of the amide compound include N-methylpyrrolidone, dimethylformamide, dimethylacetamide and the like.
Among the above organic solvents, saturated chain carbonate compounds, chain ether compounds, cyclic ether compounds and saturated chain ester compounds can lower the viscosity of the non-aqueous electrolyte and increase the mobility of electrolyte ions. Battery characteristics such as output density can be made excellent. Moreover, since it is low-viscosity, the performance of the nonaqueous electrolyte at a low temperature can be enhanced, and among them, a saturated chain carbonate compound is preferable. Examples of such saturated chain carbonate compounds include dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), ethyl butyl carbonate, methyl-t-butyl carbonate, diisopropyl carbonate, and t-butyl propyl carbonate. Etc. Examples of the chain ether compound or the cyclic ether compound include dimethoxyethane (DME), ethoxymethoxyethane, diethoxyethane, tetrahydrofuran, dioxolane, dioxane, 1,2-bis (methoxycarbonyloxy) ethane, 1,2 -Bis (ethoxycarbonyloxy) ethane, 1,2-bis (ethoxycarbonyloxy) propane, ethylene glycol bis (trifluoroethyl) ether, propylene glycol bis (trifluoroethyl) ether, ethylene glycol bis (trifluoromethyl) ether And diethylene glycol bis (trifluoroethyl) ether. Among these, dioxolane is preferred.
As the saturated chain ester compound, monoester compounds and diester compounds having a total number of carbon atoms in the molecule of 2 to 8 are preferable. Specific compounds include methyl formate, ethyl formate, methyl acetate, ethyl acetate, Propyl acetate, isobutyl acetate, butyl acetate, methyl propionate, ethyl propionate, methyl butyrate, methyl isobutyrate, methyl trimethyl acetate, ethyl trimethyl acetate, methyl malonate, ethyl malonate, methyl succinate, ethyl succinate, 3- Methyl methoxypropionate, ethyl 3-methoxypropionate, ethylene glycol diacetyl, propylene glycol diacetyl, etc., including methyl formate, ethyl formate, methyl acetate, ethyl acetate, propyl acetate, isobutyl acetate, butyl acetate, methyl propionate, and Professional Ethyl propionic acid are preferred.

In addition, acetonitrile, propionitrile, nitromethane, and derivatives thereof can also be used as the organic solvent used for preparing the liquid non-aqueous electrolyte.
The content of the electrolyte in the liquid non-aqueous electrolyte is preferably 0.5 to 3 mol / L, more preferably 0.8 to 1.8 mol / L when the electrolyte is in an organic solvent.

In the gel non-aqueous electrolyte, the above-mentioned organic solvent can be used as the liquid electrolyte combined with the polymer material.
Is mentioned.
Examples of the polymer material that is combined with the liquid electrolyte include polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), polyethylene, polyethylene oxide (PEO), and the like.
There is no restriction | limiting in particular about the usage-amount of a liquid electrolyte and a high molecular compound, and the method of compounding, What is necessary is just to employ | adopt a usage-amount and a well-known method well-known in this technical field.

  As the non-aqueous electrolyte, an ionic liquid, a polymer solid electrolyte, an inorganic solid electrolyte, or the like may be used.

An ionic liquid is an organic salt that exists as a liquid at room temperature. Examples include ionic liquids that are liquid as a single compound, liquids that are mixed with an electrolyte, and liquids that are dissolved in an organic solvent. .
The polymer solid electrolyte is obtained by solidifying a polymer material containing an electrolyte.
An inorganic solid electrolyte is a solid substance having ionic conductivity.

  An electrolyte additive can be added to the nonaqueous electrolyte used in the method for producing a secondary battery of the present invention in order to improve characteristics (battery life improvement, safety improvement). Examples of the electrolyte additive include siloxane-based and organic compounds having an unsaturated bond. When using an electrolyte additive, it is 0.01-10 mass% normally with respect to the whole nonaqueous electrolyte, Preferably, it is 0.1-5 mass%.

  In addition, halogen-based, phosphorus-based, and other flame retardants can be appropriately added to the nonaqueous electrolyte used in the method for manufacturing a secondary battery of the present invention in order to impart flame retardancy. If the amount of flame retardant added is too small, sufficient flame retarding effect cannot be achieved, and if it is too large, not only an increase effect corresponding to the blending amount can be obtained, but also adversely affect the characteristics of the non-aqueous electrolyte. Therefore, it is preferably 1 to 50% by mass, and preferably 3 to 10% by mass with respect to the organic solvent constituting the nonaqueous electrolyte used in the method for producing a secondary battery of the present invention. More preferably.

<Separator>
In the secondary battery manufactured by the secondary battery manufacturing method of the present invention, it is preferable to use a separator between the positive electrode and the negative electrode. As the separator, a polymer microporous or non-woven film usually used as a separator for a secondary battery can be used without any particular limitation. Examples of the film include polyethylene, polypropylene, polyvinylidene fluoride, polyvinylidene chloride, polyacrylonitrile, polyacrylamide, polytetrafluoroethylene, polysulfone, polyethersulfone, polycarbonate, polyamide, polyimide, polyethylene oxide and polypropylene oxide. Films composed of ethers, various celluloses such as carboxymethylcellulose and hydroxypropylcellulose, polymer compounds mainly composed of poly (meth) acrylic acid and various esters thereof, derivatives thereof, copolymers and mixtures thereof. Etc. These films may be used alone, or may be used as a multilayer film by superimposing these films. Furthermore, various additives may be used for these films, and the kind and content thereof are not particularly limited. Among these films, a film made of polyethylene, polypropylene, polyvinylidene fluoride, or polysulfone is preferably used for a secondary battery manufactured by a method for manufacturing a secondary battery.

  As these films, a non-woven film or a microporous film is used so that the electrolyte can penetrate and ions can easily permeate. The microporosity method includes a phase separation method in which a polymer compound and a solvent solution are formed into a film while microphase separation is performed, and the solvent is extracted and removed to make it porous. The film is extruded and then heat treated, the crystals are arranged in one direction, and a “stretching method” or the like is performed by forming a gap between the crystals by stretching, and is appropriately selected depending on the film used.

<Exterior member>
As the exterior member, a laminate film or a metal container can be used. The thickness of the exterior member is usually 0.5 mm or less, preferably 0.2 mm or less. Examples of the shape of the exterior member include a flat type (thin type), a square type, a cylindrical type, a coin type, and a button type.

  As the laminate film, a multilayer film having a metal layer between resin films can also be used. The metal layer is preferably an aluminum foil or an aluminum alloy foil for weight reduction. As the resin film, for example, a polymer material such as polypropylene (PP), polyethylene (PE), nylon, polyethylene terephthalate (PET) can be used. The laminate film can be formed into the shape of an exterior member by performing heat sealing.

  The metal container can be formed from, for example, aluminum or an aluminum alloy. As the aluminum alloy, an alloy containing elements such as magnesium, zinc, and silicon is preferable. In aluminum or an aluminum alloy, by setting the content of transition metals such as iron, copper, nickel, and chromium to 1% or less, long-term reliability and heat dissipation in a high temperature environment can be dramatically improved.

  In the secondary battery manufactured by the secondary battery manufacturing method, the positive electrode material, the non-aqueous electrolyte, and the separator have a phenol-based antioxidant, a phosphorus-based antioxidant, a thioether-based oxidation for the purpose of improving safety. An inhibitor, a hindered amine compound, or the like may be added.

  As described in the description of the exterior member, the secondary battery manufactured by the secondary battery manufacturing method having the above configuration is not particularly limited in shape, and various types such as a coin type, a cylindrical type, and a square type are available. It can be made into the shape. FIG. 2 shows an example of a coin-type battery of the nonaqueous electrolyte secondary battery of the present invention, and FIGS. 3 and 4 show an example of a cylindrical battery.

  In the coin-type nonaqueous electrolyte secondary battery 10 shown in FIG. 2, 1 is a positive electrode capable of releasing lithium ions, 1a is a positive electrode current collector, and 2 is a carbonaceous material capable of occluding and releasing lithium ions released from the positive electrode. The negative electrode current collector, 2a is a negative electrode current collector, 3 is a non-aqueous electrolyte, 4 is a stainless steel positive electrode case, 5 is a stainless steel negative electrode case, 6 is a polypropylene gasket, and 7 is a polyethylene separator.

  Further, in the cylindrical non-aqueous electrolyte secondary battery 10 ′ shown in FIGS. 3 and 4, 11 is a negative electrode, 12 is a negative electrode current collector, 13 is a positive electrode, 14 is a positive electrode current collector, 15 is a non-aqueous electrolyte, 16 is a separator, 17 is a positive terminal, 18 is a negative terminal, 19 is a negative electrode plate, 20 is a negative electrode lead, 21 is a positive electrode plate, 22 is a positive electrode lead, 23 is a case, 24 is an insulating plate, 25 is a gasket, 26 is a safety valve 27 are PTC elements.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the present invention is not limited to the following examples. The average particle diameter in the Examples show a D ₅₀ measured by a laser diffraction and light scattering method _(median diameter).

Example 1
<Preparation of raw material powder>
Polyacrylonitrile powder (manufactured by Sigma-Aldrich) and sulfur powder (manufactured by Kanto Kagaku) were mixed at a mass ratio of 1: 3 in the former: latter to prepare raw material powder W. The average particle size of the polyacrylonitrile powder was 10 μm, and the average particle size of the sulfur powder was 10 μm.

<Production of sulfur-modified polyacrylonitrile>
Sulfur-modified polyacrylonitrile was produced using the production apparatus 10A of FIG.
From the raw material supply device 31 provided in the raw material supply unit 30, the powder W20g was guided to the sieving device 32, and the powder W was screened by the sieving device 32 so that the average particle diameter was 10 μm. The sieved powder W was sent out into the heating unit 40 heated to 400 ° C. and heated by nitrogen gas supplied from the gas supply device 60 through the second supply path 61b. When the screened powder W is heated by the heating unit 40, the amount of nitrogen gas introduced into the heating unit 40 from the cooling unit 50 through the first supply path 61a from the gas supply unit 60 of the manufacturing apparatus 10A and the gas The amount of nitrogen gas led to the guide tube 33 in the raw material supply unit 30 from the supply device 60 through the second supply path 61b was adjusted, and the powder W was heated in the heating unit 40 at 400 ° C. for 30 seconds. And the powder W heated by the heating part 40 was guide | induced in the cooling part 50, and it cooled to 40 degreeC, and obtained the sulfur modified polyacrylonitrile of Example 1. The sulfur-modified polyacrylonitrile of Example 1 had an average particle size of 12 μm and contained 39% by mass of bound sulfur. In addition, the sulfur-modified polyacrylonitrile of Example 1 had a sulfur solid content of 0.5% by mass. In addition, adhesion of sulfur-modified polyacrylonitrile inside the apparatus was not observed. The sulfur content in the sulfur-modified polyacrylonitrile was measured by elemental analysis. The content of sulfur solid in the sulfur-modified polyacrylonitrile was measured by thermogravimetry. The thermogravimetric measurement was performed in a nitrogen gas atmosphere at a temperature range of 50 ° C. to 900 ° C. at a sweep temperature increase rate of 10 ° C. per minute.

Example 2
Sulfur-modified polyacrylonitrile was obtained in the same manner as in Example 1 except that sulfur powder having an average particle diameter of 20 μm and polyacrylonitrile powder having an average particle diameter of 20 μm were used as the raw material powder W.

  The obtained sulfur-modified polyacrylonitrile had an average particle size of 24 μm and contained 39% by mass of bound sulfur. The sulfur-modified polyacrylonitrile of Example 2 had a sulfur solid content of 0.5% by mass. In addition, adhesion of sulfur-modified polyacrylonitrile inside the apparatus was not observed. The sulfur content in the sulfur-modified polyacrylonitrile was measured by elemental analysis. The content of sulfur solid in the sulfur-modified polyacrylonitrile was measured by thermogravimetry. Thermogravimetry was performed in a nitrogen gas atmosphere at a temperature range of 50 ° C. to 900 ° C. at a sweep temperature increase rate of 10 ° C. per minute.

Comparative Example 1
A sulfur-modified polyacrylonitrile was produced using the production apparatus shown in FIG.
The same powder W used in Example 1 was used as a raw material. The powder W20g was accommodated in the reaction container. And the reaction container was heated with the heater and the powder W was made to react at 400 degreeC for 10 minute (s), and sulfur modified polyacrylonitrile was obtained. The heating was performed while discharging hydrogen sulfide generated by the reaction from the opening for discharging hydrogen sulfide. Further, in the initial stage of heating, nitrogen gas was introduced from an opening for introducing an inert gas into the reaction vessel, the inside of the reaction vessel was changed to a non-oxidizing atmosphere, and then the temperature of the powder W became 100 ° C. At that time, the opening for introducing the inert gas was closed. As a result, nitrogen gas was discharged together with the generated hydrogen sulfide, and the inside of the reaction vessel became a sulfur vapor atmosphere. That is, when the powder W was reacted at 400 ° C. for 10 minutes, the reaction vessel was in a sulfur vapor atmosphere. Since the obtained sulfur-modified polyacrylonitrile contained a sulfur solid, heat treatment was further performed at 450 ° C. to obtain the sulfur-modified polyacrylonitrile of Comparative Example 1. The sulfur-modified polyacrylonitrile of Comparative Example 1 had an average particle diameter of 1 mm or more and contained 38% by mass of bound sulfur. The sulfur-modified polyacrylonitrile of Comparative Example 1 had a sulfur solid content of 1% by mass. Part of sulfur-modified polyacrylonitrile adhered to the inside of the apparatus. The sulfur content in the sulfur-modified polyacrylonitrile was measured by elemental analysis. The content of sulfur solid in the sulfur-modified polyacrylonitrile was measured by thermogravimetry. Thermogravimetry was performed in a nitrogen gas atmosphere at a temperature range of 50 ° C. to 900 ° C. at a sweep temperature increase rate of 10 ° C. per minute.

Comparative Example 2
The same raw material powder W as in Example 2 was used, and sulfur-modified polyacrylonitrile was produced in the same manner as in Comparative Example 1 using the production apparatus of FIG. Since the obtained sulfur-modified polyacrylonitrile contained a sulfur solid, heat treatment was further performed at 450 ° C. to obtain the sulfur-modified polyacrylonitrile of Comparative Example 2. The sulfur-modified polyacrylonitrile of Comparative Example 2 had an average particle size of 1 mm or more and contained 37% by mass of bound sulfur. The sulfur-modified polyacrylonitrile of Comparative Example 2 had a sulfur solid content of 1% by mass. Part of the sulfur-modified polyacrylonitrile adhered to the inside of the apparatus. The sulfur content in the sulfur-modified polyacrylonitrile was measured by elemental analysis. The content of sulfur solid in the sulfur-modified polyacrylonitrile was measured by thermogravimetry. The thermogravimetric measurement was performed in a nitrogen gas atmosphere at a temperature range of 50 ° C. to 900 ° C. at a sweep temperature increase rate of 10 ° C. per minute.

Example 3
<Manufacture of non-aqueous electrolyte secondary batteries>
<Manufacture of electrodes>
As an active material, 79.0 parts by mass of the sulfur-modified polyacrylonitrile obtained in Example 1, 1.5 parts by mass of acetylene black (manufactured by Denki Kagaku Kogyo) as a conductive assistant, carbon nanotubes (manufactured by Showa Denko, trade name VGCF) 1.5 parts by mass and 18.0 parts by mass of polyimide (manufactured by IST) as a binder were mixed in 113 parts by mass of NMP and dispersed to form a slurry. This slurry was applied to a stainless steel current collector, dried at 120 ° C., and further heat-treated at 350 ° C. Thereafter, this electrode was cut into a predetermined size to produce a disc-shaped electrode.

<Preparation of non-aqueous electrolyte>
LiPF ₆ was dissolved at a concentration of 1 mol / L in a mixed solvent consisting of 30% by volume of ethylene carbonate, 30% by volume of dimethyl carbonate, and 40% by volume of ethyl methyl carbonate to prepare an electrolyte solution.

<Battery assembly>
The obtained disk-shaped electrode and lithium metal were used as the counter electrode, and a glass filter as a separator was sandwiched and held in the case. After that, the previously prepared non-aqueous electrolyte was poured into the case, and the case was sealed and sealed to produce the non-aqueous electrolyte secondary battery of Example 2 (φ20 mm, coin type with a thickness of 3.2 mm). did.

Example 4
A nonaqueous electrolyte secondary battery was produced in the same manner as in Example 3 except that the electrode was produced using the sulfur-modified polyacrylonitrile obtained in Example 2.

Comparative Example 3
79.0 parts by mass of the sulfur-modified polyacrylonitrile obtained in Comparative Example 1 as an active material, 1.5 parts by mass of acetylene black (manufactured by Denki Kagaku Kogyo) as a conductive auxiliary agent, carbon nanotube (manufactured by Showa Denko, trade name VGCF) 1 0.5 parts by mass and 18.0 parts by mass of polyimide (made by IST) as a binder were mixed with 113 parts by mass of NMP, but the particle size of the sulfur-modified polyacrylonitrile was large and did not become a slurry. .
Therefore, a material obtained by pulverizing the sulfur-modified polyacrylonitrile obtained in Comparative Example 1 by using a pulverizer so that the average particle diameter is 12 μm was used as an active material. A nonaqueous electrolyte secondary battery of Comparative Example 3 was obtained in the same manner as in Example 3 except that this pulverized sulfur-modified polyacrylonitrile was used.

Comparative Example 4
A nonaqueous electrolyte secondary battery was fabricated in the same manner as in Comparative Example 3 except that the electrode was manufactured using the sulfur-modified polyacrylonitrile obtained in Comparative Example 2. The sulfur-modified polyacrylonitrile obtained in Comparative Example 2 was not in the form of a slurry as it was, but was used as an active material that was pulverized using a pulverizer so that the average particle size was 12 μm.

Comparative Example 5
A nonaqueous electrolyte secondary battery was fabricated in the same manner as in Comparative Example 3 except that the sulfur-modified polyacrylonitrile obtained in Comparative Example 1 was used without being subjected to a heat treatment at 450 ° C. The sulfur-modified polyacrylonitrile before the heat treatment at 450 ° C. obtained in Comparative Example 1 was not in a slurry state as it was, and was pulverized using an pulverizer so that the average particle size was 12 μm as an active material. .

  The cycle capacity retention rates of the nonaqueous electrolyte secondary batteries of Examples 3 and 4 and Comparative Examples 3, 4 and 5 were evaluated by the following test methods.

<Cycle capacity retention test method>
The nonaqueous electrolyte secondary battery was placed in a constant temperature bath at 25 ° C., discharged at a constant current of 1.0 mA at a discharge current of 60 mA / g, and charged at a constant current of 3.0 mA at a charge current of 60 mA / g. Thereafter, a constant current discharge to 1.0 V was performed at a discharge current of 600 mA / g, and an operation of constant current charge to 3.0 V at a charge current of 600 mA / g was performed 10 times, and the 11th time to 1.0 V at a discharge current of 60 mA / g The battery was discharged at a constant current and charged at a constant current of 3.0 mA at a charging current of 60 mA / g. The charge capacity at the 11th time was defined as the charge capacity after the cycle test, and the charge capacity maintenance rate (%) was determined as the ratio of the charge capacity after the cycle test when the initial charge capacity was 100 as shown in the following formula. .
Charge capacity maintenance rate (%) = [(charge capacity after cycle test) / (initial charge capacity)] × 100

  The nonaqueous electrolyte secondary batteries of Examples 3 and 4 had a charge capacity maintenance rate of 89% and 91%, respectively. On the other hand, the non-aqueous electrolyte secondary batteries of Comparative Examples 3, 4 and 5 had charge capacity maintenance rates of 85%, 85% and 71%, respectively. From the above results, it became clear that the sulfur-modified polyacrylonitrile obtained by the production method of the present invention is useful as an active material for electrodes.

DESCRIPTION OF SYMBOLS 1 Positive electrode 1a Positive electrode collector 2 Negative electrode 2a Negative electrode collector 3 Electrolyte 4 Positive electrode case 5 Negative electrode case 6 Gasket 7 Separator 10 Coin type nonaqueous electrolyte secondary battery 10 'Cylindrical nonaqueous electrolyte secondary battery 11 Negative electrode 12 Negative electrode current collector 13 Positive electrode 14 Positive electrode current collector 15 Electrolyte 16 Separator 17 Positive electrode terminal 18 Negative electrode terminal 19 Negative electrode plate 20 Negative electrode lead 21 Positive electrode plate 22 Positive electrode lead 23 Case 24 Insulating plate 25 Gasket 26 Safety valve 27 PTC element 10A Sulfur-modified polyacrylonitrile Manufacturing apparatus 30 raw material supply section 31 raw material supply apparatus 32 sieving apparatus 33 guide tube 40 heating section 40A extension section 41 heating apparatus 50 cooling section 51 guide member 60 gas supply apparatus 61a first supply path 61b second supply path 62a first Flow control valve 62b Second flow control valve 63 Control device 70 Exhaust gas section 71 Exhaust gas treatment 72 pressure measuring instrument D insulation material W powder

Claims (7)

A raw material supply unit that supplies a raw material powder containing polyacrylonitrile powder and sulfur powder, a heating unit that heat-treats the powder that is supplied and dropped from the raw material supply unit, and cools the heat-treated powder A method for producing sulfur-modified polyacrylonitrile using a drop-type powder processing apparatus equipped with a cooling unit,
A method for producing sulfur-modified polyacrylonitrile, comprising a step of supplying a gas from the lower side and / or the upper side of the heating unit to control a falling speed of the powder falling in the heating unit.   The falling powder processing apparatus is provided with an exhaust gas part that exhausts the exhaust gas in the heating part to the outside above the heating part, and the exhaust gas part is provided with an exhaust gas treatment device that renders the exhaust gas harmless. Item 2. A process for producing a sulfur-modified polyacrylonitrile according to Item 1.   The drop type powder processing apparatus having a mechanism for controlling a falling speed of the powder falling in the heating unit by a gas supplied from the lower side and / or the upper side of the heating unit. Of producing sulfur-modified polyacrylonitrile.   The exhaust gas unit having a pressure measuring device for measuring the pressure in the heating unit, and a control for adjusting the amount of gas introduced into the heating unit according to the pressure in the heating unit measured by the pressure measuring device The manufacturing method of the sulfur modified polyacrylonitrile of Claim 2 using the said drop type powder processing apparatus which has an apparatus.   The method for producing sulfur-modified polyacrylonitrile according to any one of claims 1 to 4, wherein the raw material further contains a conductive additive.   The manufacturing method of the electrode for secondary batteries which has a process of manufacturing sulfur modification polyacrylonitrile by the manufacturing method of sulfur modification polyacrylonitrile of any one of Claims 1-5.   The manufacturing method of a secondary battery which has the process of manufacturing the electrode for secondary batteries by the manufacturing method of the electrode for secondary batteries of Claim 6.