JP5578532B2 - Power storage device - Google Patents

Description

  The present invention relates to a power storage device, and more particularly to a high capacity power storage device with an increased amount of anion or cation intercalation.

  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, in Patent Document 1, in an electric double layer capacitor in which two polarizable electrodes are immersed in an organic electrolyte, the carbon material constituting the two polarizable electrodes is at least one of an alkali metal and an alkali metal compound. A carbon material having microcrystalline carbon similar to graphite, which is produced by performing heat treatment at a temperature higher than the temperature at which alkali metal vapor is generated together with seeds, and the expression of capacitance is organic between the microcrystalline carbon layers of the carbon material. A technique is described that achieves an electrostatic capacity and a withstand voltage that exceed those of a conventional activated carbon type electric double layer capacitor by being configured to be performed by inserting ions of a solute in an electrolytic solution.

  Also, in Patent Document 2, a polarizable electrode mainly composed of a carbon material having a partially oxidized graphite-like microcrystalline carbon is immersed in an organic electrolyte, and the polarizable electrode expands in volume by charging. In addition, an electric field activation method for an electrochemical capacitor that shrinks in volume by electric discharge is described. In this technique, the constant current charge in the first charge is performed at a current lower than the current used in actual use, and / or the first charge is a predetermined voltage that is greater than the actual use voltage and less than the decomposition voltage of the electrolyte. After the constant current charging is performed, the constant voltage charging is performed until the relaxation current becomes sufficiently small at a predetermined voltage. As a result, by optimizing the initial charging conditions, it is possible to improve the capacitance density even when the same polarizable electrode is used.

  Further, in Patent Document 3, graphite, which is a carbon material having a layered structure, is used as a material for a positive electrode conductive material layer, and a carbon material having a high specific surface area is used as a material for a negative electrode conductive material layer. A power storage device using activated carbon is described. Moreover, 1-n-butylpyridinium hexafluorophosphate is included as the organic electrolyte material of the nonaqueous electrolytic solution, and propylene carbonate and ethyl methyl carbonate are included as the solvent. According to the present technology, the anion in the non-aqueous electrolyte is intercalated between the positive electrode layers, and the cation is adsorbed on the outermost surface of the negative electrode, so that the capacity per weight can be increased and the energy storage capacity can be increased. be written.

Patent Document 4 discloses a carbonaceous material having a layered structure in which a plurality of amorphous portions are dispersed on the (002) plane, and the average area of the amorphous portions 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 2000-77273 A JP 2001-223143 A JP 2008-166268 A 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 greatly expand in the future. The demand for higher capacity is also high from the point of expectation.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an electricity storage device having an increased capacity by increasing the amount of anion or cation intercalation.

  As a result of intensive studies to achieve the above object, the inventors of the present invention used a carbonaceous material having a layered structure as a positive electrode and a carbonaceous material preliminarily adsorbed with lithium ions as a negative electrode in a power storage device. By driving so that the maximum voltage at the time is within a predetermined range, the inventors have found a new finding that the capacity density and / or the output density is superior to the conventional power storage device, and have completed the present invention. That is, the present invention includes the following configurations.

(1) Power storage 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 carbonaceous material included in the positive electrode is a carbonaceous material having a layered structure, and is the following (i) or (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,
The carbonaceous material included in the negative electrode is an electricity storage device in which lithium ions are occluded in advance. Note that in this power storage device, it is preferable to perform charging / discharging in the range of 5.0 V to 5.4 V as the maximum charging / discharging voltage.

(2) The electricity storage device according to (1), wherein the carbonaceous material included in the positive electrode is a carbonaceous material taken out from the positive electrode obtained by a production method including the following steps (a) to (d):
(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) 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;
(D) The voltage application process which makes charging voltage at the time of charge larger than 2.25V and 3.5V or less and performs at least one charging / discharging cycle.

  (3) The electric storage device according to (1) or (2), wherein the carbonaceous material included in the negative electrode is obtained by electrochemically reacting the negative electrode and lithium metal.

  (4) The electricity storage device according to any one of (1) to (3), wherein the carbonaceous material included in the positive electrode is graphite.

  (5) The electricity storage device according to any one of (1) to (4), wherein the carbonaceous material included in the negative electrode is graphite or non-graphitizable carbon.

  (6) The electricity storage device according to (2), wherein the carbonaceous material of the positive electrode in the step (a) is graphite, and the carbonaceous material of the negative electrode in the step (b) is activated carbon.

  (7) In the step (b), the negative electrode is prepared by coating the surface of the electrode plate with a carbonaceous material having a mass of 6 to 18 times the mass of the carbonaceous material of the positive electrode. The electricity storage device described.

(8) The electrical storage device according to (2), wherein, in the step (c), triethylmethylammonium tetrafluoroborate (TEMA.BF ₄ ) is used as an electrolyte in the nonaqueous electrolytic solution.

  (9) The electricity storage device according to (2), wherein in the step (c), a solvent containing a cyclic carbonate and a chain carbonate is used as a solvent in the nonaqueous electrolytic solution.

  (10) In the step (c), as the non-aqueous electrolyte, a non-aqueous electrolyte including an electrolyte containing an anion that can be intercalated between layers of a carbonaceous material and a fluorine-containing organic solvent is used (2 ).

(11) A power storage device including 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. a device, carbonaceous material wherein the positive electrode comprises the ratio of the peak intensity of 1360 cm ^-1 to the peak intensity of 1580 cm ^-1 in the Raman spectrum is that from 0.25 to 0.33, and the half width of 1580 cm ^-1 electricity storage device but a carbonaceous material is 18cm ^-1 ~22cm ^-1, carbonaceous material wherein the negative electrode comprises is one in which lithium ions are occluded in advance.

  According to the electricity storage device of the present invention, the amount of anion or cation intercalation can be increased, and an effect of achieving a high capacity can be achieved.

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 cell at the time of positive electrode preparation for using for the electrical storage device which concerns on the Example of this invention. It is a figure which shows the relationship between the energy density at the time of charging / discharging and an output density about the electrical storage device of an Example and a comparative example. It is a figure which shows the result of having measured the charge capacity at the time of a positive electrode process, the discharge capacity, and the discharge capacity of the last electrical storage device about the electrical storage device of an Example and a comparative example. It is a figure which shows the result of having evaluated the capacity | capacitance maintenance factor at the time of repeating charging / discharging about the electrical storage device of an Example and a comparative example.

  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. Power storage device>
An electricity storage device according to the present invention 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 And an electricity storage device. Hereinafter, various components will be described.

<2. Carbonaceous material contained in positive electrode>
As the carbonaceous material included in the positive electrode, it is preferable to use a carbonaceous material having a layered structure, which is one 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.

<2-1. Embodiment 1 of Manufacturing Method>
Moreover, the carbonaceous material which the said positive electrode contains can be taken out from the positive electrode obtained by the manufacturing method containing the following processes (a)-(d).
(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) 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;
(D) The voltage application process which makes charging voltage at the time of charge larger than 2.25V and 3.5V or less and performs at least one charging / discharging cycle.

  By producing the carbonaceous material by the above method, the above-mentioned amorphous part can be formed in the carbonaceous material having a layered structure, and the ion intercalation sites 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 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 non-aqueous electrolyte, and a 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.

  A charge / discharge cycle in which a constant current is passed between the positive electrode and the negative electrode of the cell thus prepared for charging and then discharging is performed once.

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. The carbonaceous material for positive electrodes used for the electrical storage device according to the present invention can be obtained by extracting graphite from the positive electrode by the above method.

  Moreover, as a carbonaceous material which the positive electrode in this invention contains, the thing of Unexamined-Japanese-Patent No. 2010-254537 can also be utilized, for example.

<2-2. Second Embodiment of Manufacturing Method>
As another aspect of the method for producing a carbonaceous material included in the positive electrode, the step “b” described in the section <2-1> “carbon having a mass four times or more the mass of the carbonaceous material of the positive electrode. In the step of preparing a negative electrode by coating a porous material on the electrode plate surface, the electrode plate surface is coated with a carbonaceous material having a mass of 6 to 18 times the mass of the carbonaceous material of the positive electrode. A step of preparing the negative electrode can be preferably exemplified.

  Thus, when the mass ratio of the negative electrode (for example, activated carbon is the main component) opposed to the positive electrode during the charge / discharge treatment of the positive electrode is set to 6 to 18 times, the device capacity density is increased and the charge / discharge is repeated. The occurrence of a decrease in capacity can be suppressed.

  For this reason, if it is the manufacturing method of this aspect, a device with a high initial capacity | capacitance density and few performance degradation at the time of repeated charging / discharging can be manufactured. This is presumed that an appropriate positive electrode potential is operated during the charge / discharge treatment during the manufacture of the positive electrode. That is, when the negative electrode capacity is small, it is presumed that the positive electrode potential does not rise to the required level and the anion doping does not proceed efficiently. On the other hand, when the negative electrode capacity is large, the positive electrode potential rises too much, resulting in the decomposition of the electrolyte solution. This decomposition product causes a decrease in capacity density and a decrease in performance during repeated charge and discharge. It is thought to cause.

  Since the production method of this aspect does not cause the above-described problems, excellent capacity density and long-term stability can be achieved.

<2-3. Embodiment 3 of Manufacturing Method>
As another embodiment of the method for producing the carbonaceous material included in the positive electrode, the step (c) described in the section <2-1> “Non-containing anion capable of intercalating between layers of the carbonaceous material of the positive electrode. In the step of “facing the positive electrode and the negative electrode in the aqueous electrolyte”, a method of using triethylmethylammonium tetrafluoroborate (TEMA.BF ₄ ) as the electrolyte in the non-aqueous electrolyte can be preferably exemplified.

When TEMA · BF ₄ is used as an electrolyte, charging / discharging is repeated as compared with the case of using another electrolyte (for example, triethylmethylammonium hexafluorophosphate (TEMA · PF ₆ )). The capacity is improved by about 10%. This is presumed to be the following mechanism. That is, when the positive electrode treatment cell uses BF ₄ anion and the electricity storage device uses another anion (for example, PF ₆ ) as an anion inserted into the positive electrode, the PF ₆ anion has an ionic radius compared to the BF ₄ anion. Therefore, it is considered that the amorphous part in the crystal structure of the carbonaceous material in the positive electrode formed by BF ₄ anion insertion during the positive electrode treatment was further expanded by the insertion of PF ₆ anion in the electricity storage device.

  Therefore, in this production method, the ionic radius of the anion in the electrolyte in the electrolytic solution used in the cell at the time of the positive electrode treatment is smaller than the ionic radius of the anion in the electrolytic solution in the electrolytic solution used in the finally produced electricity storage device. In other words, the method uses an electrolyte.

  In order to stably increase the capacity of the electricity storage device, a charge / discharge treatment process at the time of manufacturing the positive electrode is important. In this treatment, anion insertion into the carbonaceous material of the positive electrode is performed, but the positive electrode capacity is determined depending on how efficiently the anion insertion is performed, and the final capacity of the power storage device is affected. According to this production method, anion insertion during the positive electrode treatment can be carried out efficiently, so that an increase in capacity during repeated charge / discharge can be achieved.

<2-4. Embodiment 4 of Manufacturing Method>
Further, as another embodiment of the method for producing a carbonaceous material included in the positive electrode, the step (c) described in the section <2-1> “an anion capable of intercalating between the layers of the carbonaceous material of the positive electrode. In the step of “facing the positive electrode and the negative electrode in the nonaqueous electrolyte solution”, a method using a solvent containing a cyclic carbonate and a chain carbonate as the solvent in the nonaqueous electrolyte solution can be preferably exemplified. Here, although it does not specifically limit about each carbonate to be used, For example, a propylene carbonate (PC) can be used conveniently as a cyclic carbonate. As the chain carbonate, for example, at least one selected from the group consisting of dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC), or a combination thereof can be suitably used.

  Moreover, although mass ratio of a cyclic carbonate and a chain carbonate is not specifically limited, For example, 1: 1 to 1: 5 can be illustrated. However, since it is said that the solubility of the electrolyte tends to decrease as the amount of the chain carbonate increases, it is preferable that the range does not cause such a problem. For example, it is particularly preferable that the mass ratio of cyclic carbonate and chain carbonate performed in the examples is 1: 1.

The electrolyte in the non-aqueous electrolyte is not particularly limited, but as described in the section <2-3>, the ionic radius of the anion in the electrolyte in the electrolyte used in the cell during the positive electrode treatment is It is preferable to use an electrolyte that is smaller than the ionic radius of the anion in the electrolyte in the electrolytic solution used in the electricity storage device to be finally produced. For example, triethylmethylammonium tetrafluoroborate (TEMA.BF ₄ ) can be mentioned.

  According to the manufacturing method of this aspect, the capacity | capacitance at the time of charging / discharging of a positive electrode improves. Furthermore, the charge / discharge capacity of an electricity storage device (final full cell) produced using the positive electrode taken out therefrom as a material is also improved. This is presumably due to the following mechanism.

  That is, during the charge / discharge treatment during the positive electrode treatment, it is considered that the electrolytic solution is also being decomposed when the positive electrode potential increases to a certain value or more in parallel with the insertion of ions into the positive and negative electrodes. It is presumed that a specific positive electrode is formed as a result of the ion insertion and the decomposition of the electrolytic solution. Here, since the chain carbonate has a higher withstand voltage compared to the cyclic carbonate, the use of a mixture of the cyclic cardnate and the chain carbonate suppresses the decomposition of the electrolytic solution, resulting in the positive electrode capacity. Is considered to have improved.

  Therefore, if it is the manufacturing method of this aspect, the outstanding capacity density and long-term stability can be achieved.

<2-5. Embodiment 5 of Manufacturing Method>
Further, as another embodiment of the method for producing a carbonaceous material included in the positive electrode, the step (c) described in the section <2-1> “an anion capable of intercalating between the layers of the carbonaceous material of the positive electrode. In the step of making the positive electrode and the negative electrode face each other in the nonaqueous electrolyte solution containing, the nonaqueous electrolyte solution includes an electrolyte containing an anion capable of intercalating between layers of a carbonaceous material, and a fluorine-containing organic solvent. A method using a water electrolyte can be preferably exemplified.

  As such a fluorine-containing organic solvent, it is preferable to use a fluorine-containing organic solvent instead of carbonates or lactones from the following viewpoints. That is, even when a voltage of 3 V or higher is applied, chemical decomposition hardly occurs. Further, it is possible to avoid the risk of ignition during overcharge / overheating due to the low flash point and high combustibility. In addition, since the viscosity is difficult to increase, the decrease in conductivity can be reduced even at low temperatures, and the decrease in output can be suppressed (low temperature characteristics). It is easy to use because the hydrolyzability can be lowered. Such an electrolytic solution 14 is particularly preferably a non-aqueous electrolytic solution that is highly soluble in electrolyte salt, stable even under basic conditions, and excellent in compatibility with a hydrocarbon solvent. As such a fluorine-containing organic solvent, an electrolytic solution is represented by the following formula (I):

(Wherein X ^{1 to} X ⁶ are the same or different, and all are H, F, Cl, CH ₃ or a fluorine-containing methyl group; provided that at least one of X ^{1 to} X ⁶ is a fluorine-containing methyl group) It is preferable that it is a fluorine-containing lactone shown by these.

^The fluorine-containing methyl group in X 1 to X ⁶ _are, -CH 2 F, a -CHF ₂ and CF _3, -CF ₃ terms withstand voltage is good is preferred. The fluorine-containing methyl group may be substituted for all of X ^{1 to} X ⁶ or only one. Preferably, the number is 1 to 3, particularly 1 to 2, in view of good solubility of the electrolyte salt. Further, the substitution position of the fluorine-containing methyl group is not particularly limited, but since the synthesis yield is good, X ³ and / or X ⁴ is particularly X ⁴ is a fluorine-containing methyl group, particularly —CF _3. Is preferred. X ^{1 to} X ⁶ other than the fluorine-containing methyl group are H, F, Cl or CH ₃ , and H is particularly preferable from the viewpoint of good solubility of the electrolyte salt.

  In the fluorine-containing lactone, the atom other than the fluorine-containing methyl group bonded to the carbon atom constituting the lactone ring is preferably F and / or H. The electrolyte salt is preferably an ammonium salt, and particularly preferably a tetraalkyl quaternary ammonium salt, a spirobipyridinium salt, or an imidazolium salt.

  The fluorine content of the fluorine-containing lactone is 10% by mass or more, preferably 20% by mass or more, particularly 30% by mass or more, and the upper limit is usually 76% by mass, preferably 55% by mass. The method for measuring the fluorine content of the whole fluorine-containing lactone can be measured by a usual method such as a combustion method.

  Since fluorine-containing lactone is contained, even when adding fluorine-containing ether that improves flame retardancy, it is difficult to separate into two layers and a uniform state can be obtained.

Examples of the fluorine-containing organic solvent include 4-trifluoromethyl-1,3-dioxolan-2-one and 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether ( And a mixed solvent of HCF ₂ CF ₂ CH ₂ OCF ₂ CF ₂ H).

  Moreover, the solvent as described above can be preferably used those described in JP 2008-016560 A, JP 2010-226100 A, and JP 2011-097118 A.

  Moreover, about the electrolyte to be used, a conventionally well-known thing can be used and it does not specifically limit.

  According to the manufacturing method of this embodiment, the capacity during charging and discharging of the positive electrode is improved. Furthermore, the charge / discharge capacity of the electricity storage device (final full cell) using the positive electrode taken out therefrom is also improved. This is presumed to be the following mechanism.

  That is, as described above, during the charge / discharge treatment during the positive electrode treatment, in parallel with the insertion of ions into the positive and negative electrodes, the decomposition of the electrolyte proceeds when the positive electrode potential increases to a certain value or more. As a result of the insertion of and the competition for electrolyte decomposition, a specific positive electrode is formed. Here, compared with hydrocarbon solvents such as carbonates and lactones, the fluorine-containing organic solvent has a high withstand voltage, so that the decomposition of the electrolytic solution is suppressed, and as a result, the capacity of the positive electrode is considered to be improved. .

  Therefore, if it is the manufacturing method of this aspect, the outstanding capacity density and long-term stability can be achieved.

<2-6. Other embodiment of carbonaceous material contained in positive electrode>
Further, carbonaceous material positive electrode comprises according to the present invention, the ratio of the peak intensity of 1360 cm ^-1 to the peak intensity of 1580 cm ^-1 in the Raman spectrum is from 0.25 to 0.33, and the half width of 1580 cm ^-1 it is preferred but a carbon material is ^{18cm -1 ~22cm} -1. It can be presumed that the carbonaceous material having such physical properties has a structure in which the edge surface ratio is increased as a result of cleaving the plate-like structure without impairing the regularity of the graphite layered structure. By using this carbonaceous material as an active material for the positive electrode, the amount of anion or cation intercalation into the electrode material can be increased, and the capacity of the power storage device can be increased.

  The Raman spectrum is obtained by irradiating the carbonaceous material with an argon laser (light source wavelength 514.5 nm).

Here, "the ratio of the peak intensity of 1360 cm ^-1 to the peak intensity of 1580 cm ^-1 by Raman spectrum", reflects the ratio of the edge of the graphite crystal surface, the ratio of the higher edge ratio becomes larger increases, non There is a tendency to be crystalline.

The “half-width of 1580 cm ⁻¹ by Raman spectrum” reflects the degree of graphitization (completeness of local graphite structure). If this value decreases, the proportion of the basal surface increases and the orientation becomes high. On the other hand, when this value increases, the degree of graphitization decreases and the film becomes amorphous.

That is, in the present invention, the ratio of the peak intensity of 1360 cm ^-1 to the peak intensity of 1580cm ^-1 by Raman spectrum is that from 0.25 to 0.33, and 1580cm half width ^18cm -1 ～22Cm ^{-1 -1} In other words, the carbonaceous material is a carbonaceous material that is particularly preferable for use as a carbonaceous material included in the positive electrode.

Examples of the method for producing the carbonaceous material include an electrochemical method, but are not limited thereto. For example, as the raw material, the half value width 18cm argon laser (light source wavelength 514.5 nm) and the ratio of the peak intensity of 1360 cm ^-1 by Raman spectrum to the peak intensity of 1580 cm ^-1 is 0.05 to 0.3 1580 cm ^{-1 A} carbonaceous material having a layered structure of ^{−1 to} 22 cm ⁻¹ can be used.

  It can be said that this raw material has a structure in which the degree of graphitization is developed, that is, the regularity of the graphite layered structure is established, and the edge surface is small, that is, a structure developed in a plate shape. An electrode is produced by forming such a raw material as a main component on a current collector, using it as a positive electrode, and using an electrode formed on the current collector with active carbon as a main component on the negative electrode side, and impregnating with a non-aqueous electrolyte. Charge and discharge. This material can be formed by this method. For example, the method described in the section <2-1> can be preferably used.

  The carbonaceous material thus obtained has the above-described physical properties. Therefore, for example, the carbonaceous material can be used as a positive electrode, the activated carbon electrode can be used as a negative electrode, and a non-aqueous electrolyte can be filled to form an asymmetric capacitor. On the other hand, this is used as a positive electrode, and as the negative electrode, an electrode mainly composed of carbon that can occlude Li, such as graphite or non-graphitizable carbon, is used, and a cell is configured through a cellulose-based or polyolefin-based separator. In a cell impregnated with a lithium ion electrolyte such as lithium hexafluorohyphosphate / EC or DEC, a secondary battery is formed by pre-doping lithium ions into the negative electrode by a known method. Can do. In the case of this battery, charging / discharging can be performed within the maximum voltage range of 5.0 V to 5.4 V, and a larger storage capacity than that of a known lithium ion battery can be generated. By using such a carbonaceous material for the positive electrode, the amount of anion doping can be improved and the capacity density of the electricity storage device can be improved.

<3. Carbonaceous material contained in the negative electrode>
Moreover, it is preferable to use the carbonaceous material in which lithium ion is occluded beforehand as a carbonaceous material which the said negative electrode contains.

  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 of manufacturing an electrode from a carbonaceous material, a carbon 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, or the like is dissolved, and a conductive aid. It is preferable to disperse the 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.

<4. Other configurations>
As the solute lithium salt of the organic electrolyte solution in the present invention, LiPF ₆ , LiBF ₄ , LiCIO ₄ , LiN (CF ₃ SO ₂ ) ₂ , LiN (SO ₂ C ₂ F ₅ ) ₂ , LiCF ₃ SO ₃ , LiC ( _{SO 2 CF 3) 3, LIAsF} 6, and one or more is preferably selected from the group consisting of LiSbF _6.

  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.

<5. 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 is lowered. 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 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. And
As a positive electrode, 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 four times or more the mass of the carbonaceous material of the positive electrode A step of coating a surface 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 that can be intercalated between the layers of the carbonaceous material of the positive electrode, and charging during charging The voltage is made greater than 2.25V and less than or equal to 3.5V, through a voltage application step of performing at least one charge / discharge cycle,
As the negative electrode, an electricity storage device in which lithium ions are previously stored by electrochemically reacting a negative electrode containing a carbonaceous material capable of inserting and extracting lithium ions with lithium metal. Note that in this power storage device, it is preferable to perform charging / discharging in the range of 5.0 V to 5.4 V as the maximum charging / discharging voltage.
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 cell when producing a positive electrode for use in an electricity storage device according to an example 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. The thickness of the positive electrode sheet excluding the thickness of the aluminum foil at this time is 400 μm. The active material mass ratio of the negative electrode to the positive electrode at this time was 10 times.

A positive electrode 11 and a negative electrode 14 are arranged to face each other through a cellulose-based porous separator 13 and are provided with a take-out electrode portion that leads out to the outside, and is covered with an aluminum laminate film (collection of member numbers 12 and 15 for the positive electrode and the negative electrode, respectively) Body 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. A direct current power source was connected to the positive and negative electrodes, the battery was charged from 0 to 3.5V, and immediately discharged to 0V.

  After the discharge, 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, an electrolyte solution is impregnated with 1.0M lithium hexafluorophosphate (LiPF ₆ ) and ethylene carbonate / dimethyl carbonate (1: 1) mixed solvent solution, the laminate exterior is sealed, and the electricity storage device cell is Produced.

  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.

[Comparative Example 1]
A known method in which both the positive electrode and the negative electrode use the same activated carbon electrode as the negative electrode for positive electrode treatment 14 of Example 1 and impregnate a 1.6 M triethylmethylammonium tetrafluoroborate (TEMA.BF ₄ ) propylene carbonate solution as an electrolyte. An electric double layer capacitor was manufactured at

[Comparative Example 2]
The same activated carbon electrode as the negative electrode for positive electrode treatment 14 of Example 1 was used as the positive electrode, the same graphite electrode as that of the negative electrode 4 of Example 1 was used as the negative electrode, and 1.0 M lithium hexafluorophosphate (LiPF) was used as the electrolyte. ₆ ) Impregnated with an ethylene carbonate / dimethyl carbonate (1: 1) solution, and thereafter, in the same manner as in Example 1, lithium ions were previously stored in the negative electrode to produce a lithium ion capacitor.

<Result>
In each of the electricity storage devices of Example 1 and Comparative Examples 1 and 2, charging and discharging were repeated while changing the discharge current density, and the relationship between the discharge current density and the discharge capacity at that time was obtained. The result is shown in FIG. Charge / discharge is performed in the voltage range of 3V to 5.3V for the electricity storage device of Example 1, 0V to 2.7V for the electricity storage device of Comparative Example 1, and 2.8V to 4.0V for the electricity storage device of Comparative Example 2. went. In any case, when charging / discharging was repeated beyond this voltage range, it was confirmed that the performance was remarkably lowered with repeated charging / discharging.

  Further, the capacity density (energy density) and output density of the electricity storage device of Example 1 obtained from the characteristics were compared with the characteristics of known general electricity storage devices.

  As shown in Table 1, it can be seen that the capacity density (energy density) and / or output density of the electricity storage device of Example 1 is superior to known electricity storage devices.

[Example 2]
A laminate cell in which the thickness of the negative electrode sheet excluding the thickness of the aluminum foil of the negative electrode during charge / discharge treatment during the production of the positive electrode is 240 μm, the active material mass ratio of the negative electrode to the positive electrode is 6 times, and the laminate sheath is sealed Example 1 except that 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 with a pressure of 100 N / cm ² being sandwiched between 10 mm thick stainless steel plates. A power storage device was produced in the same manner as described above.

Example 3
Except for the thickness of the negative electrode sheet excluding the thickness of the aluminum foil of the negative electrode during the charge / discharge treatment during the production of the positive electrode, the thickness was 400 μm, and the active material mass ratio of the negative electrode to the positive electrode was 10 times. An electricity storage device was fabricated.

Example 4
The same as in Example 2 except that the thickness of the negative electrode sheet excluding the thickness of the aluminum foil of the negative electrode during charge / discharge treatment during the production of the positive electrode was 700 μm and the active material mass ratio of the negative electrode to the positive electrode was 18 times. An electricity storage device was fabricated.

Example 5
The same as in Example 2 except that the thickness of the negative electrode sheet excluding the thickness of the negative electrode aluminum foil during the charge / discharge treatment during the production of the positive electrode was 160 μm and the active material mass ratio of the negative electrode to the positive electrode was 4 times. An electricity storage device was fabricated.

[Comparative Example 3]
Except for the thickness of the negative electrode sheet excluding the thickness of the aluminum foil of the negative electrode during the charge / discharge treatment during the production of the positive electrode, the thickness is 1000 μm, and the active material mass ratio of the negative electrode to the positive electrode is 25 times. An electricity storage device was fabricated.

[Comparative Example 4]
Same as Example 2 except that the thickness of the negative electrode sheet excluding the thickness of the aluminum foil of the negative electrode during the charge / discharge treatment during the production of the positive electrode was 80 μm and the active material mass ratio of the negative electrode to the positive electrode was doubled. An electricity storage device was fabricated.

  In each of the electricity storage devices of Examples 2 to 5 and Comparative Examples 3 and 4, the charge capacity at the time of positive electrode treatment (at the time of positive electrode manufacture), the discharge capacity, and the discharge capacity of the final electricity storage device were measured. Table 2 and FIG. Indicated. Moreover, about the electrical storage device of Examples 2-4 and Comparative Example 3, the capacity | capacitance maintenance factor at the time of repeating charging / discharging was shown in FIG.

  As shown in Table 2 and FIG. 4, in Examples 2 to 5, the charge capacity / discharge capacity during the positive electrode treatment and the discharge capacity of the final power storage device are both high. Moreover, as shown in FIG. 5, in Examples 2-5, the capacity | capacitance maintenance factor at the time of repeating charging / discharging was also favorable. On the other hand, in Comparative Example 3, the charge capacity / discharge capacity at the time of the positive electrode treatment and the discharge capacity of the final power storage device are both high, but as shown in FIG. Low. In Comparative Example 4, both the charge capacity / discharge capacity during the positive electrode treatment and the discharge capacity of the final power storage device were low.

Example 6
As in Example 1 except that a propylene carbonate (PC) solution of 1.6M triethylmethylammonium tetrafluoroborate (TEMA · BF ₄ ) was used as the electrolyte used during the charge / discharge treatment during the production of the positive electrode. A device was fabricated.

  For each storage device of Example 1 for comparison with Example 6, the discharge capacity at the time of positive electrode treatment, the discharge capacity of the final storage device, and the capacity after repeating 200 cycles of charge / discharge were measured, It was shown in 3.

As shown in Table 3, when TEMA · BF ₄ is used as the electrolyte used during the charge / discharge treatment during the production of the positive electrode, the discharge capacity after repeating 200 cycles of charge / discharge is improved by about 10%. I found out that

Example 7
Except that a mixed solvent solution of 0.7M TEMA · BF ₄ in propylene carbonate (PC): ethyl methyl carbonate (EMC) (1: 1) was used as an electrolyte used in the charge / discharge treatment during the production of the positive electrode. An electricity storage device was produced in the same manner as in Example 1.

Example 8
Example 1 except that a mixed solvent solution of 0.7 M TEMA · BF ₄ in propylene carbonate (PC): diethyl carbonate (DEC) (1: 1) was used as the electrolyte used during the charge / discharge treatment during the production of the positive electrode. A power storage device was produced in the same manner as described above.

Example 9
Example 1 except that a mixed solvent solution of propylene carbonate (PC): dimethyl carbonate (DMC) (1: 1) of 0.7 M TEMA · BF ₄ was used as the electrolyte used during the charge / discharge treatment during the production of the positive electrode. A power storage device was produced in the same manner as described above.

  For each of the electricity storage devices of Examples 7 to 9 and Example 6 for comparison, the discharge capacity during positive electrode treatment and the discharge capacity of the final device were measured and are shown in Table 4.

  As shown in Table 4, when (i) PC which is a cyclic carbonate and (ii) EMC, DEC or DMC which is a chain carbonate are used in combination, compared with the case where only the cyclic carbonate is used, the discharge It was found that the capacity was excellent.

Example 10
As an electrolytic solution used at the time of charge / discharge treatment at the time of manufacturing the positive electrode, a fluorine-containing organic solvent-based electrolytic solution (for the electrolytic solution, 4-trifluoromethyl-1,3-dioxolan-2-one and 1,1,2,2 are used. -. except for using that was used by dissolving 1.5M TEMA · BF ₄ in a mixed solvent of tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether), as in example 1 An electricity storage device was fabricated.

  For comparison with Example 10 and each power storage device of Example 1, the discharge capacity during positive electrode treatment and the discharge capacity of the final power storage device were measured and are shown in Table 5.

  As shown in Table 5, it was found that when a fluorine-containing organic solvent was used as the electrolytic solution used during the charge / discharge treatment during the production of the positive electrode, the discharge capacity was increased.

Example 11
Graphite (KS6: manufactured by Timcal) was used as a carbonaceous material used as a raw material when manufacturing the positive electrode. The ratio of the peak intensity of 1360 cm ^-1 to the peak intensity of the raw argon laser 1580cm by (light source wavelength 514.5 nm) Raman spectrum ^-1 is 0.19, the half width of 1580cm ^-1 was 19cm ^-1 . Using this raw material, a positive electrode was produced in the same manner as in Example 1. After discharging, the cell was disassembled and only the positive electrode was taken out. The ratio of the peak intensity of 1360 cm ^-1 by an argon laser (light source wavelength 514.5 nm) Raman spectrum of the electrode to the peak intensity of 1580 cm ^-1 is 0.33, the half width of 1580 cm ^-1 was 20 cm ^-1 .

[Comparative Example 5]
Graphite (KS6: manufactured by Timcal) was used as a carbonaceous material used as a raw material when manufacturing the positive electrode. The ratio of the peak intensity of 1360 cm ^-1 by an argon laser (light source wavelength 514.5 nm) Raman spectrum of this material to the peak intensity of 1580 cm ^-1 is 0.19, the half width of 1580 cm ^-1 was 19cm ^-1 . An electrode was produced in the same manner using this material, and an electricity storage device was produced using it as it was without passing through the positive electrode formation step in Example 1.

  Table 6 shows the capacity densities of the electricity storage devices of Example 11 and Comparative Example 5.

As shown in Table 6, when the peak intensity ratio and the half width of 1360 cm ^-1 to the peak intensity of 1580 cm ^-1 by Raman spectra is within a predetermined range, it was found that the discharge capacity is increased.

  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 (6)

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. And
The carbonaceous material included in the positive electrode is a carbonaceous material having a layered structure, and is the following (i) or (ii):
(I) a carbonaceous material in which a plurality of amorphous portions are dispersed in the (002) plane and the average area of the amorphous portions is 1.5 nm ² or more; or (ii) a non-crystalline portion 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,
The carbonaceous material included in the negative electrode is graphite or non-graphitizable carbon and has lithium ions occluded in advance. The electrical storage device according to claim 1, wherein the carbonaceous material included in the positive electrode is a carbonaceous material extracted from the positive electrode obtained by a manufacturing method including the following steps (a) to (d):
(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) 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;
(D) The voltage application process which makes charging voltage at the time of charge larger than 2.25V and 3.5V or less and performs at least one charging / discharging cycle.   The power storage device according to claim 1 or 2, wherein the carbonaceous material included in the negative electrode is obtained by electrochemically reacting the negative electrode and lithium metal.   The electric storage device according to claim 1, wherein the carbonaceous material included in the positive electrode is graphite.   The electrical storage device according to claim 2, wherein the carbonaceous material of the positive electrode in the step (a) is graphite, and the carbonaceous material of the negative electrode in the step (b) is activated carbon.   In the step (b), a negative electrode is prepared by coating a surface of an electrode plate with a carbonaceous material having a mass of 6 to 18 times the mass of the carbonaceous material of the positive electrode. 3. The electricity storage device according to 2.

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