JP2014116559A - Method for manufacturing carbonaceous material and use of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a carbonaceous material for manufacturing of a high-capacity power storage device.SOLUTION: According to the method for manufacturing a carbonaceous material which contains a voltage application process for performing a charge/discharge cycle to a laminated cell for manufacturing the carbonaceous material with a charging voltage of larger than 2.25 V and 3.5 V or less at charging while applying compression pressure of 100 N/cmto 400 N/cmin a surface direction, the carbonaceous material for stably manufacturing the high-capacity power storage device can be stably manufactured.

Description

  TECHNICAL FIELD The present invention relates to a method for producing a carbonaceous material and use thereof, and in particular, a method for producing a carbonaceous material for stably producing a high-capacity electricity storage device having an increased amount of anion or cation intercalation and the method thereof. It is about use.

  Conventionally, small batteries have been developed to reduce the size and weight of various portable devices such as personal computers and mobile phones. In order to reduce the size and weight of various portable devices, it is essential that the energy density of the battery as a power source is high. In addition to small batteries, large batteries are also being developed as power storage devices mounted on electric vehicles and hybrid vehicles. Such a large battery is required to have a high energy density and a high output density.

Research and development of lithium ion secondary batteries, electric double layer capacitors, and the like have been actively conducted to meet the above requirements. For example, Patent Document 1 discloses a carbonaceous material having a layered structure in which a plurality of amorphous parts are dispersed on the (002) plane, and the average area of the amorphous parts is 1.5 nm ² or more. A certain carbonaceous material or the like is described, and it is disclosed that when this is used in a power storage device, the amount of ion intercalation can be increased to realize a high capacity of the power storage device.

JP 2010-254537 A

  As described above, various technical developments have been made on power storage devices such as lithium ion secondary batteries and electric double layer capacitors. However, in the field of power storage devices, it is very important to increase the capacity of power storage devices, and in order to make it possible to use such power storage devices as power sources for automobiles and general equipment, further increase in capacity is required. It is done.

  Recently, a new market has emerged as storage batteries for automobiles such as hybrid cars and electric cars, and new energy systems such as solar batteries and wind power generation, and the market for lithium-ion batteries will expand significantly in the future. The demand for higher capacity is also high from the point of expectation.

  This invention is made | formed in view of the said subject, The objective is to provide the manufacturing method of the carbonaceous material for manufacturing a high capacity | capacitance electrical storage device stably, and its utilization technique.

  In order to achieve the above-mentioned object, the present inventors have intensively studied the manufacturing process of the carbonaceous material used for the positive electrode of the electricity storage device. As a result, when a carbonaceous material obtained by charging / discharging treatment while applying a predetermined compression pressure in the plane direction to the laminated cell at the time of manufacturing the positive electrode was used as a positive electrode, an electricity storage device was stably produced. As a result, the present inventors have found a new finding that can be obtained. That is, the present invention includes the following configurations.

(1) (a) a step of preparing a positive electrode by coating a carbonaceous material having a layered structure on the surface of an electrode plate; and (b) carbon having a mass four times or more the mass of the carbonaceous material of the positive electrode. (C) the positive electrode and the negative electrode are opposed to each other in a non-aqueous electrolyte containing an anion that can be intercalated between the layers of the carbonaceous material of the positive electrode. And (d) applying a compression pressure of 100 N / cm ² or more and 400 N / cm ² or less in the surface direction to the stacked cell, and setting the charging voltage during charging to 2.25 V. And a voltage application step of performing at least one charge / discharge cycle at a voltage of 3.5 V or less.

(2) The method for producing a carbonaceous material according to (1), wherein in the step (d), a compression pressure applied in a plane direction with respect to the stacked cell is 200 N / cm ² or more and 400 N / cm ² or less.

  (3) The method for producing a carbonaceous material according to (1) or (2), wherein the carbonaceous material of the positive electrode is graphite and the carbonaceous material of the negative electrode is activated carbon.

  (4) A carbonaceous material taken out from the positive electrode, produced by the method for producing a carbonaceous material according to any one of (1) to (3).

  (5) An electricity storage device comprising the carbonaceous material according to (4) as a positive electrode active material.

  (6) The power storage device includes a positive electrode including a carbonaceous material having a layered structure capable of adsorbing and desorbing anions, a negative electrode including a carbonaceous material capable of absorbing and desorbing lithium ions, and an organic electrolyte including a lithium salt The carbonaceous material included in the negative electrode is a power storage device according to (5) in which lithium ions are stored in advance.

  (7) The electric storage device according to (5) or (6), wherein the carbonaceous material included in the negative electrode is obtained by electrochemically reacting the negative electrode and lithium metal.

  (8) The electricity storage device according to any one of (5) to (7), wherein the carbonaceous material included in the negative electrode is graphite or non-graphitizable carbon.

  ADVANTAGE OF THE INVENTION According to this invention, the carbonaceous material for positive electrodes in a high capacity | capacitance electrical storage device can be manufactured stably. For this reason, there exists an effect that a high capacity | capacitance electrical storage device can be manufactured stably.

It is a schematic diagram which shows the structure of the basic cell 10 of the electrical storage device which concerns on the Example of this invention. It is a schematic diagram which shows the structure of the lamination | stacking cell at the time of positive electrode preparation for using for the electrical storage device which concerns on the Example of this invention.

  An embodiment of the present invention will be described in detail below. All academic and patent documents mentioned in this specification are hereby incorporated by reference. Unless otherwise specified in this specification, “A to B” indicating a numerical range means “A or more and B or less”. “%” Means “% by weight” and “parts” means “parts by weight”.

<1. Manufacturing method of carbonaceous material>
The method for producing a carbonaceous material according to the present invention includes:
(A) coating the surface of the electrode plate with a carbonaceous material having a layered structure to prepare a positive electrode;
(B) a step of preparing a negative electrode by coating the surface of the electrode plate with a carbonaceous material having a mass four times or more the mass of the carbonaceous material of the positive electrode;
(C) The step of making the positive electrode and the negative electrode face each other in a nonaqueous electrolytic solution containing an anion capable of intercalation between the layers of the carbonaceous material of the positive electrode, and producing a stacked cell;
(D) Applying a compression pressure of 100 N / cm ² or more and 400 N / cm ² or less to the layered cell in the plane direction, and setting a charging voltage at the time of charging more than 2.25V to 3.5V or less at least once Voltage application step of performing the charge and discharge cycle of
Any other specific configuration is not particularly limited.

In the step (d), it is more preferable that the compression pressure applied in the plane direction with respect to the stacked cell is 200 N / cm ² or more and 400 N / cm ² or less. In the charge / discharge treatment during the production of the positive electrode, the high-capacity density can be stably obtained by setting the compression pressure in the plane direction of the laminated cell to 100 to 400 N / cm ² , more preferably 200 to 400 N / cm ² .

  Here, a conventionally known method can be used as a method of applying a compression pressure in the plane direction to the stacked cell, and is not particularly limited. For example, a method of sandwiching a laminated cell between two metal plates such as stainless steel plates and applying a compression pressure uniformly can be exemplified.

  According to this manufacturing method, in the step (d), the distance between the electrodes is reduced and the internal resistance is reduced as compared with the case where no compression pressure is applied to the stacked cell in the surface direction. It is considered that the variation in the number is also reduced. Thereby, it can be presumed that the use of the decomposition active point of the electrolytic solution is reduced, the decomposition of the electrolytic solution is suppressed, and the efficiency of anion insertion into the positive electrode is increased.

  The carbonaceous material for the positive electrode is preferably graphite, and the carbonaceous material for the negative electrode is preferably activated carbon.

  Further, by producing the carbonaceous material by the production method, the above-mentioned amorphous part can be formed in the carbonaceous material having a layered structure, and the ion intercalation site can be increased. Moreover, the amorphous part remains even after discharge. Therefore, when this carbonaceous material is used as an electrode for an electricity storage device, electrolyte ions preferentially and easily intercalate with the amorphous part of the carbonaceous material, so intercalation in the carbonaceous material The amount can be increased, and the discharge capacity of the electricity storage device can be improved. This is presumed to be related to the presence or absence of the formation of an amorphous part in the graphite, the increase in the interlayer distance, and the amount of intercalation. That is, it can be said that the amorphous part is increased and the interlayer distance is increased, and as a result, the anion is preferentially intercalated with respect to the amorphous part and the amount of stored electricity is increased.

  The manufacturing method including the steps (a) to (d) will be described below. First, a carbonaceous material having a layered structure is prepared. Here, graphite is used as the carbonaceous material in this embodiment. Graphite has a layered structure on the (002) plane. The (002) plane is intended to be a carbon 002 plane (plane parallel to the graphite layer) measured by X-ray diffraction. The carbonaceous material having a layered structure is preferably graphite, but is not limited to graphite, and a carbonaceous material having a layered structure can be appropriately employed.

Next, an electrode plate (aluminum foil) is prepared and the surface of this electrode plate is covered with graphite to form a positive electrode. Also, an electrode plate for a negative electrode is prepared, and the surface of this electrode plate is coated with activated carbon as a negative electrode material to form a negative electrode. The carbonaceous material coated on the surface of the negative electrode plate is not limited to activated carbon, and any carbonaceous material having a large surface area and capable of adsorbing cations can be employed. Preferably, the carbonaceous material of the negative electrode is activated carbon having a specific surface area of 2000 m ² / g or more. Here, the weight of the carbonaceous material of the negative electrode (activated carbon in this embodiment) is 4 times or more, preferably 8 times or more, more preferably 10 times or more of the weight of the carbonaceous material of the positive electrode (graphite in this embodiment). To.

Next, the positive electrode and the negative electrode are arranged so as to face each other with a separator interposed between them, and are covered with a laminate film, impregnated with a nonaqueous electrolytic solution, and a laminated cell is produced. Here, as the non-aqueous electrolyte, a mixture of a supporting salt having an anion that can be intercalated between the graphite layers of the positive electrode in an appropriate solvent is used. For example, triethylmethylammonium hexafluoro is used as the supporting salt. A phosphate (TEMMAPF ₆ ) or the like can be used.

The stacked cell thus prepared is charged by flowing a constant current between the positive electrode and the negative electrode of the stacked cell while applying a compression pressure of 100 N / cm ² or more and 400 N / cm ² or less in the plane direction, Thereafter, a charge / discharge cycle is performed once. Here, the compression pressure may be 200 N / cm ² or more and 400 N / cm ² or less.

Charging is performed at a constant current of, for example, a current density of 1.85 mA / cm ² until the voltage reaches a predetermined voltage. Here, the predetermined voltage at the time of charging is selected between 2.25V and 3.5V or less. In addition, the charge / discharge cycle is not limited to one, and may be performed a plurality of times. In short, it may be performed at least once. When a charging current is passed through the electrode, cations in the non-aqueous electrolyte are adsorbed by the activated carbon of the negative electrode, and the anions are intercalated between the graphite layers of the positive electrode. After charging to a predetermined voltage, this time, discharging is performed to 0V. A carbonaceous material can be acquired by taking out graphite from a positive electrode by the above method.

  In addition, regarding the said method, you may use the technique of Unexamined-Japanese-Patent No. 2010-254537 suitably, for example.

  According to the method for producing a carbonaceous material, a carbonaceous material for a positive electrode in a high-capacity electricity storage device can be produced stably. For this reason, a high-capacity electrical storage device can be manufactured stably.

<2. Carbonaceous material>
Moreover, the carbonaceous material taken out from the said positive electrode manufactured by the manufacturing method of the carbonaceous material mentioned above is also included by this invention.

  As shown in Examples described later, the carbonaceous material according to the present invention is excellent in that the discharge capacity at the time of charge / discharge treatment during the production of the positive electrode is larger than that of the conventional one. For example, in the step (d), compared to the carbonaceous material obtained by producing the laminated cell without applying a compression pressure in the plane direction, the discharge capacity at the time of charge / discharge treatment at the time of positive electrode production is 1.3 to 1.6 times better.

In addition, the carbonaceous material obtained by this production method is a carbonaceous material having a layered structure, and is preferably any of the following (i) and (ii).
(I) a carbonaceous material in which a plurality of amorphous parts are dispersed in the (002) plane and the average area of the amorphous parts is 1.5 nm ² or more; or (ii) a non-crystalline part in the (002) plane. A plurality of crystalline parts are dispersed, and the ratio of the total area of the amorphous part in the (002) plane to the total area of the amorphous part and the crystalline part in the (002) plane is , 30% or more carbonaceous material.

  For example, the carbonaceous material (i) increases the number of ion intercalation sites because a plurality of amorphous parts having an appropriate area are dispersed on the (002) plane of the carbonaceous material having a layered structure. Can be made. Moreover, since these amorphous portions remain after discharge, when this carbonaceous material is used as an electrode of a power storage device, electrolyte ions are preferentially and easily added to the amorphous portions of the carbonaceous material. Therefore, the amount of intercalation in the carbonaceous material can be increased, and the discharge capacity of the power storage device can be improved.

  In the case of the carbonaceous material (ii), a plurality of amorphous portions having an appropriate ratio are dispersed on the (002) plane of the carbonaceous material having a layered structure, and the area ratio is 30% or more. Therefore, the ion intercalation site can be increased. And this amorphous part remains after discharge. Therefore, when this carbonaceous material is used as an electrode of a power storage device, electrolyte ions preferentially and easily intercalate into the amorphous part of the carbonaceous material, and therefore intercalation in the carbonaceous material. The amount can be increased, and the discharge capacity of the power storage device can be improved.

<3. Power storage device>
The electricity storage device according to the present invention is not particularly limited as long as it includes the carbonaceous material according to <2> as a positive electrode active material.

  The power storage device includes a positive electrode including a carbonaceous material having a layered structure capable of adsorbing and desorbing anions, a negative electrode including a carbonaceous material capable of absorbing and desorbing lithium ions, and an organic electrolytic solution including a lithium salt. The carbonaceous material included in the negative electrode is a material in which lithium ions are occluded in advance, and the maximum charge / discharge voltage of the power storage device is 5.0 V or more and 5.4 V or less. It is preferable to perform charging / discharging within a range.

  In the case of this configuration, the “positive electrode including a carbonaceous material having a layered structure capable of adsorbing and desorbing anions” includes the carbonaceous material described in <2> as a positive electrode active material. With respect to the positive electrode, any material may be used as long as it includes the carbonaceous material described in <2> as a positive electrode active material, and other configurations are not limited, and conventionally known techniques can be suitably used.

  Below, each structure of an electrical storage device, such as the carbonaceous material which the said negative electrode contains, is demonstrated.

<3-1. Carbonaceous material contained in the negative electrode>
Further, as the carbonaceous material included in the negative electrode, a carbonaceous material in which lithium ions are occluded in advance is used.

  The carbonaceous material included in the negative electrode is preferably obtained by electrochemically reacting the negative electrode and lithium metal. As a method of electrochemically reacting the negative electrode and the lithium metal in order to occlude lithium ions in advance in the negative electrode, for example, the metal foil of the negative electrode current collector and the lithium metal are electrochemically short-circuited and electrolysis is performed. This is done by pouring the liquid into the container. Moreover, the lithium electrode arrange | positioned so that it may not contact a negative electrode directly may be provided, and an electric current may be flowed between a negative electrode and a lithium electrode.

  The amount of lithium ion to be stored in advance is a (mAh), the cell capacity when the power storage device is charged to a predetermined voltage after storage is b (mAh), and the negative electrode is 3.0 VLi / Li + to 0.01 VLi / When the capacity when charged to Li + is c (mAh), the negative electrode capacity is determined so that 3 ≦ c / b ≦ 10, and preferably 1.2 ≦ c / a ≦ 5. .

  The negative electrode capacity is preferably determined so as to satisfy 3 ≦ c / b ≦ 10. If it is in this range, since the negative electrode capacity is not too small compared with the electricity storage device capacity, a sufficient amount of lithium ions can be occluded in advance in the negative electrode. Further, an increase in the weight of the negative electrode can be suppressed and an increase in the weight of the power storage device can be prevented, so that the capacity density of the power storage device does not decrease.

  The amount of lithium ions stored in advance is preferably 1.2 ≦ c / a ≦ 5. Within this range, the amount of lithium ions previously occluded in the negative electrode is an appropriate amount, so that the capacity density can be maintained, and the capacity reduction during float charging can be prevented.

  As the carbonaceous material, graphite, non-graphitizable carbon, natural graphite, artificial graphite, non-graphitizable carbon, graphitizable carbon, low-temperature calcined carbon, etc. are preferable, and in particular, graphite or non-graphitizable carbon is used. preferable.

  As a method for producing an electrode from a carbonaceous material, a conductive material and a carbonaceous material that can occlude and desorb lithium ions in a slurry in which a mixture of carboxymethyl cellulose and SBR rubber as a binder, polyvinylidene fluoride, polyamideimide, polyimide, etc. are dissolved. It is preferable to disperse the auxiliary material, apply this liquid onto the current collector by the doctor blade method or the like, and dry it. The amount of the binder contained in the electrode is preferably 1 to 20% by weight.

  As the carbonaceous material included in the negative electrode, for example, those described in JP 2009-260187 A may be used.

<3-2. Other configurations>
The solute lithium salt of the organic electrolyte in the electricity storage device of the present invention includes LiPF ₆ , LiBF ₄ , LiCIO ₄ , LiN (CF ₃ SO ₂ ) ₂ , LiN (SO ₂ C ₂ F ₅ ) ₂ , LiCF ₃ SO _3. One or more selected from the group consisting of LiC (SO ₂ CF ₃ ) ₃ , LIAsF ₆ , and LiSbF ₆ are preferred.

  The electrolyte concentration of the lithium salt in the organic solvent electrolyte is preferably 0.5 to 2.5 mol / L. The concentration of the entire electrolyte is more preferably 0.75 to 2.0 mol / L.

  Examples of the solvent for the electrolytic solution include propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, sulfolane, and dimethoxyethane. These can be used alone or as a mixed solution of two or more. .

  Moreover, it is preferable to constitute a cell through a cellulose-based or polyolefin-based separator.

  In addition, conventionally well-known things can be used as an organic electrolyte solution, a solute, and a separator material, and use of things other than the above-mentioned is not excluded.

<3-3. Maximum charge / discharge voltage>
In the electricity storage device according to the present invention, it is preferable to perform charge / discharge in the range of 5.0 V or more and 5.4 V or less of the maximum charge / discharge voltage of the electricity storage device.

  In the cell (power storage device) having the above-described configuration, it is possible to generate a larger storage capacity than a power storage device such as a known lithium ion battery by performing charge and discharge in the range of the maximum voltage of 5.0 V to 5.4 V. it can. For example, according to the electricity storage device of the present invention, a conventional hybrid capacitor (charge / discharge voltage range of about 0V to 3.5V), EDLC (charge / discharge voltage range of about 0V to 2.7V), lithium ion capacitor (charge / discharge voltage) Either the capacity density or the output density compared to the conventional high-capacity lithium ion battery (charge / discharge voltage range of about 2.8V to 3.6V). On the other hand, it has the effect of being large in both points.

  Here, “the range where the maximum voltage is 5.0 V or more and 5.4 V or less” intends the range of the upper limit voltage in the charge / discharge voltage of the electricity storage device. The effect is small because the charge / discharge capacity is reduced as the value of the maximum voltage of the charge / discharge voltage decreases. However, in the electricity storage device according to the present invention, the maximum voltage of the charge / discharge voltage is 5.0 V or more. Discharge capacity is obtained. On the other hand, if the upper limit voltage exceeds 5.4 V, the decomposition of the electrolytic solution proceeds and the characteristics deteriorate, which is not preferable. In addition, the lower limit voltage in the charging / discharging voltage of an electrical storage device should just be 3V vicinity, and is not specifically limited.

  As described above, the electricity storage device according to the present invention is a high-capacity storage battery having a maximum charge / discharge voltage of 5.0 V to 5.4 V. For this reason, in addition to various portable devices such as mobile phones and notebook computers, it can be suitably used as a storage battery for power storage in combination with a storage battery for an automobile such as a hybrid vehicle or an electric vehicle, or a new energy system such as a solar battery or wind power generation.

  Moreover, the manufacturing method of the electrical storage device which includes the manufacturing method of the carbonaceous material as described in said <1> as 1 process can also be included in this invention. Specifically, for example, the method for producing a carbonaceous material according to <1> is provided as one step, and a carbonaceous material is obtained from a positive electrode obtained by the method for producing a carbonaceous material according to <1>. A method of producing a positive electrode by taking it out and using it as a positive electrode active material to produce a cell of an electricity storage device can be mentioned. In addition, about the process for manufacturing another electrical storage device, a conventionally well-known technique can be used and it does not specifically limit.

  Moreover, the following invention is also included by the electrical storage device which concerns on this invention.

1. An electricity storage device having a positive electrode including a carbonaceous material having a layered structure capable of adsorbing and desorbing anions, a negative electrode including a carbonaceous material capable of absorbing and desorbing lithium ions, and an organic electrolyte containing a lithium salt. The positive electrode includes a step of preparing a positive electrode by coating a carbonaceous material having a layered structure on the surface of the electrode plate, and a carbonaceous material having a mass of 4 times or more the mass of the carbonaceous material of the positive electrode. A step of coating the surface of the electrode plate to prepare a negative electrode, a step of making the positive electrode and the negative electrode face each other in a non-aqueous electrolyte containing an anion capable of intercalation between the layers of the carbonaceous material of the positive electrode, and during charging The charging voltage of 2.25V and 3.5V or less was manufactured through a voltage application step of performing at least one charge / discharge cycle, and the negative electrode occludes lithium ions, In an electricity storage device characterized in that lithium ions are occluded in advance by electrochemically reacting a negative electrode containing a detachable carbonaceous material with lithium metal, and charging / discharging at the time of manufacturing the positive electrode The electrical storage device which implements a process on the conditions of the compression pressure of the surface direction of a lamination | stacking cell of 100-400 N / cm < ² >, More preferably, 200-400 N / cm < ² >. In addition, in this electrical storage device, it is preferable to perform charging / discharging in the range whose maximum voltage of charging / discharging voltage is 5.0V to 5.4V.

  2. The carbonaceous material of the “positive electrode including a carbonaceous material having a layered structure capable of adsorbing and desorbing anions” is graphite.

  3. The carbonaceous material of the “negative electrode containing a carbonaceous material capable of inserting and extracting lithium ions” is graphite or non-graphitizable carbon.

  4). The carbonaceous material in the “step of preparing a negative electrode by coating the surface of the electrode plate with a carbonaceous material having a mass 4 times or more the mass of the carbonaceous material of the positive electrode” is activated carbon.

  The present invention is not limited to the configurations described above, and various modifications can be made within the scope described in the specification, and implementations obtained by appropriately combining technical means disclosed in different embodiments. The form is also included in the technical scope of the present invention. Moreover, all the literatures described in this specification are used as reference. EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited only to this Example.

  Hereinafter, the present invention will be described in more detail with reference to examples. The present invention is not limited to the following examples.

[Example 1]
FIG. 1 is a schematic diagram showing a configuration of a basic cell 10 of an electricity storage device according to an embodiment of the present invention. In FIG. 1, 1 is a positive electrode (main component: graphite) which is a polarizable electrode, 2 is a positive electrode current collector foil and external extraction electrode (aluminum foil), 3 is a separator (cellulose), and 4 is a negative electrode which is a carbonaceous electrode. (Main component: Graphite) 5 is a negative electrode current collector foil and an external extraction electrode (copper foil), 6 is a lithium metal, and 7 is a lithium metal electrode extraction electrode (nickel). A lithium metal 6 is pressure-bonded to the lithium metal electrode lead electrode 7 and a lithium electrode is disposed so as not to be in direct contact with the negative electrode 4. Hereinafter, production of the positive electrode 1, the negative electrode 4, and the cell 10 will be described.

<Production of positive electrode 1>
FIG. 2 is a schematic diagram showing the configuration of a stacked cell during the production of a positive electrode for use in an electricity storage device according to an embodiment of the present invention. In FIG. 2, 11 is a positive electrode (main component: graphite) which is a polarizable electrode, 12 is a positive electrode current collector foil and an external extraction electrode made of aluminum foil, 13 is a separator (cellulose), 14 is a negative electrode which is a carbon electrode ( Main component: activated carbon), 15 is a negative electrode current collector foil made of aluminum foil and an external extraction electrode. Further, as the electrolytic solution, TEMA · PF ₆ (triethylmethylammonium hexafluorophosphate) / PC · EMC (propylene carbonate / ethylmethyl carbonate) was used.

  Specifically, polyvinylidene fluoride is dissolved in N-methyl-2-pyrrolidone, graphite (KS6: Timcal) is dispersed as an active material, this solution is applied to an aluminum foil with a doctor blade and dried. Thus, the positive electrode 11 was manufactured. The thickness of the coated electrode after drying is 80 μm and the weight ratio of graphite: polyvinylidene fluoride is 90:10.

As the negative electrode 14 for positive electrode treatment, 80% by weight of activated carbon having a specific surface area of 2000 m ² / g obtained by steam activation of petroleum coke, 10% by weight of conductive carbon black, 10% by weight of polytetrafluoroethylene as a binder, ethanol After being kneaded and rolled using, and formed into a sheet shape, a negative electrode 14 was manufactured by bonding to an aluminum foil using a conductive adhesive. Here, the weight of the activated carbon of the negative electrode was set to 10 times the weight of the graphite of the positive electrode. The thickness of the positive electrode sheet excluding the thickness of the aluminum foil at this time is 400 μm.

The positive electrode 11 and the negative electrode 14 are opposed to each other through a cellulose-based porous separator 13 and are provided with an extraction electrode portion that leads out to the outside, and is covered with an aluminum laminate film (current collectors of member numbers 12 and 15 for the positive electrode and the negative electrode, respectively) Foil and external extraction electrode). After vacuum drying at 120 ° C. for 8 hours, a 0.7 M TEMA / PF ₆ / PC / EMC (1: 2) mixed solvent solution was impregnated as an electrolyte, and the laminate exterior was sealed.

The laminate cell was sandwiched between 10 mm thick stainless steel plates, and with a pressure of 100 N / cm ² applied, a DC power source was connected to the positive and negative electrodes, charged from 0 to 3.5 V, and immediately discharged to 0 V.

  After discharging, the cell was disassembled and only the positive electrode was taken out. This is used as the positive electrode 1.

<Production of negative electrode 4>
Manufactured by dissolving polyvinylidene fluoride in N-methyl-2-pyrrolidone, dispersing artificial graphite (graphite) capable of occluding and desorbing lithium ions, applying this solution to copper foil with a doctor blade and drying. . The thickness of the coated negative electrode after drying is 130 μm, and the weight ratio of artificial graphite: polyvinylidene fluoride is 90:10.

<Production of electricity storage device (cell 10)>
A positive electrode current collector foil and an external extraction electrode 2 are provided so that the positive electrode 1 and the negative electrode 4 manufactured previously face each other through a cellulose-based porous separator 3 and lead out to the outside. Further, lithium metal 6 is used as an electrode for lithium ion doping. An electrode (lithium metal electrode lead-out electrode) 7 that was placed on a current collector made of nickel and was crimped and led out to the outside was provided and covered with an aluminum laminate film. After vacuum drying at 120 ° C. for 8 hours, 1.0 M lithium hexafluorophosphate (LiPF ₆ ) and ethylene carbonate / dimethyl carbonate (1: 1) mixed solvent solution are impregnated as an electrolytic solution, the laminate exterior is sealed, and the electricity storage device cell 10 Was made.

  The negative electrode 4 and the lithium electrode of the cell 10 thus produced were short-circuited through an external circuit, so that the negative electrode 4 was previously occluded with lithium ions. When the amount of lithium ions occluded in the negative electrode measured using an external circuit reached 70% of the theoretical occlusion amount, occlusion was terminated.

[Example 2]
A cell was manufactured under the same conditions as in Example 1 except that the compression pressure during the charge / discharge treatment during the production of the positive electrode was 200 N / cm ² .

Example 3
A cell was manufactured under the same conditions as in Example 1 except that the compression pressure at the time of charge / discharge treatment during the production of the positive electrode was 400 N / cm ² .

[Comparative Example 1]
A cell was produced under the same conditions as in Example 1 except that the compression pressure during the charge / discharge treatment during the production of the positive electrode was 50 N / cm ² .

[Comparative Example 2]
A cell was produced under the same conditions as in Example 1 except that the compression pressure during the charge / discharge treatment during the production of the positive electrode was 500 N / cm ² .

<Result>
In each of the devices of Examples and Comparative Examples, the discharge capacity at the time of charge / discharge treatment during positive electrode manufacture and the discharge capacity at the time of charge / discharge of the final electricity storage device (cell) were measured and shown in Table 1.

  As shown in Table 1, it can be seen that the electricity storage devices of Examples 1 to 3 are excellent in the discharge capacity at the time of charge / discharge treatment at the time of manufacturing the positive electrode and the discharge capacity at the time of charge / discharge of the final electricity storage device (cell). . In addition, the electrical storage device of Comparative Example 2 was not chargeable, and the discharge capacity could not be measured. This is presumably because the carbonaceous material for the positive electrode was destroyed because the compression pressure at the time of manufacturing the positive electrode was too strong.

  The present invention relates to various fields such as various mobile devices such as mobile phones and notebook computers, storage batteries for automobiles such as hybrid cars and electric cars, and storage batteries for power storage combined with new energy systems such as solar batteries and wind power generation. Can be widely used.

DESCRIPTION OF SYMBOLS 1 Positive electrode 2 Positive electrode collector foil and external extraction electrode 3 Separator 4 Negative electrode 5 Negative electrode collector foil and external extraction electrode 6 Lithium metal 7 Lithium metal electrode extraction electrode 10 Power storage device 11 Positive electrode 12 Positive electrode collector foil and external extraction electrode 13 Separator 14 Negative Electrode 15 Negative Electrode Current Foil and External Extraction Electrode

Claims (8)

(A) coating the surface of the electrode plate with a carbonaceous material having a layered structure to prepare a positive electrode;
(B) a step of preparing a negative electrode by coating the surface of the electrode plate with a carbonaceous material having a mass four times or more the mass of the carbonaceous material of the positive electrode;
(C) a step of making a stacked cell by making the positive electrode and the negative electrode face each other in a nonaqueous electrolytic solution containing an anion capable of intercalation between layers of the carbonaceous material of the positive electrode;
(D) Applying a compression pressure of 100 N / cm ² or more and 400 N / cm ² or less to the layered cell in the plane direction, and setting a charging voltage at the time of charging more than 2.25V to 3.5V or less at least once Voltage application step of performing the charge and discharge cycle of
The manufacturing method of the carbonaceous material characterized by including. ^{2. The} method for producing a carbonaceous material according to claim 1, wherein in the step (d), a compression pressure applied in a plane direction with respect to the stacked cell is 200 N / cm ² or more and 400 N / cm ² or less. .   The method for producing a carbonaceous material according to claim 1 or 2, wherein the carbonaceous material of the positive electrode is graphite and the carbonaceous material of the negative electrode is activated carbon.   A carbonaceous material produced by the method for producing a carbonaceous material according to claim 1, wherein the carbonaceous material is taken out from the positive electrode.   An electrical storage device comprising the carbonaceous material according to claim 4 as a positive electrode active material. The power storage device includes a positive electrode including a carbonaceous material having a layered structure capable of adsorbing and desorbing anions, a negative electrode including a carbonaceous material capable of absorbing and desorbing lithium ions, and an organic electrolyte including a lithium salt. An electricity storage device comprising:
The electrical storage device according to claim 5, wherein the carbonaceous material included in the negative electrode is a material in which lithium ions are previously stored.   The electric storage device according to claim 5 or 6, wherein the carbonaceous material contained in the negative electrode is obtained by electrochemically reacting the negative electrode and lithium metal. The power storage device according to claim 5, wherein the carbonaceous material included in the negative electrode is graphite or non-graphitizable carbon.

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