Negative electrode

Abstract

To provide graphene permeable to lithium ions and usable in electrical devices.SOLUTION: A carbon ring having 9 or more ring members is provided in graphene. The carbon ring having 9 or more ring members has a maximum potential for lithium ions of approximately 0 electron volts and therefore can function as a gap allowing lithium ion permeation. When such graphene is used to coat the surface of an electrode or an active material, the reaction between the electrode or active material and an electrolyte can be suppressed without hindering the movement of lithium ions.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a material having high lithium permeability and conductivity, which can be applied to materials for lithium ion secondary batteries, etc. It is related to graphene or multilayer graphene with excellent electrical conductivity. Graphene is a type of 2 It is a one-atom-thick sheet of carbon molecules with bonds. [Background technology]

[0002] Graphene has excellent electrical properties such as high conductivity and mobility, as well as flexibility and mechanical strength. Due to its physical properties, attempts have been made to apply it to various products (Patent Document 1 to Patent Document 5). (See Reference 3.) Technology for applying graphene to lithium-ion secondary batteries has also been proposed. (Patent Document 4). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] US Patent Publication No. 2011 / 0070146 [Patent Document 2] U.S. Patent Publication No. 2009 / 0110627 [Patent Document 3] U.S. Patent Publication No. 2007 / 0131915 [Patent Document 4] US Patent Publication No. 2010 / 0081057 Summary of the Invention [Problem to be solved by the invention]

[0004] Graphene is known to have high electrical conductivity. Graphene is a material that does not absorb ions. However, by creating gaps in some parts of the graphene, ions can pass through. It is possible to give the player the ability to

[0005] The larger the gaps in the graphene and the more gaps there are per unit area, the more efficient it becomes. This allows ions to pass through, but the mechanical strength of graphene decreases. One aspect of the present invention has been made to solve this problem, and is based on the idea of ​​providing gaps in graphene. One of the objectives is to optimize the size, number, and mechanical strength of graphene.

[0006] Another object of one embodiment of the present invention is to provide a power storage device with excellent charge and discharge characteristics. Alternatively, one of the objectives is to increase the storage capacity per unit weight. One of the purposes of the present invention is to improve the cycle characteristics. One of the objectives of the present invention is to provide highly reliable electrical equipment that can withstand long-term use. [Means for solving the problem]

[0007] One aspect of the present invention is characterized in that a carbon ring having 9 or more ring members is provided in graphene. The nine-membered carbon ring has a maximum potential energy of almost 0 for the lithium ion. Since the number of ring members is nine or more, the lithium-ion can be It can function as a gap through which ON can pass.

[0008] In one aspect of the present invention, a 0.149 nm 2 The present invention is characterized in that a gap of at least The area of ​​the gap in the graphene is set to 0.149 nm 2 By doing the above, lithium It allows ions to easily pass through.

[0009] When such graphene is coated on the surface of an electrode or active material, it does not impede the movement of lithium ions. Furthermore, reactions between the electrodes or active materials and the electrolyte can be suppressed.

[0010] Another embodiment of the present invention is an electrical device including the above-described graphene. One embodiment of the present invention is an electrode or an active material having a surface covered with the above-mentioned graphene. To solve any one of the above problems. Effect of the Invention

[0011] According to one embodiment of the present invention, the charge and discharge rate of a power storage device can be increased.

[0012] According to one aspect of the present invention, the power storage capacity per unit weight can be increased.

[0013] According to one aspect of the present invention, cycle characteristics can be improved. [Brief description of the drawings]

[0014] [Figure 1] A diagram showing the optimal structure of carbon rings formed in graphene. [Diagram 2] A diagram explaining the change in potential energy that a lithium ion receives from a carbon ring. [Diagram 3] FIG. 2 is a diagram for explaining the relationship between the area a of a gap provided in graphene and the area S of graphene containing one gap. [Figure 4] FIG. 1 is a diagram illustrating the movement of lithium ions. [Diagram 5] 1A and 1B are diagrams illustrating the structure of a coin-type secondary battery. [Figure 6] 1A and 1B are diagrams illustrating an example of an electrical device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an embodiment will be described. However, the embodiment can be embodied in many different ways. and may be modified in various forms and details without departing from the spirit and scope of the present invention. It will be readily understood by those skilled in the art that the present invention may be modified in various ways. The present disclosure is not to be construed as being limited to the contents of the description of the embodiment.

[0016] (Embodiment 1) In this embodiment, the size of the gaps provided in the graphene, the number density of the gaps (the number of the graphene unit surfaces We discuss how to optimize the pore size (number of voids per unit area) and mechanical strength of graphene. Reveal.

[0017] FIG. 1 shows the optimal structure of carbon rings formed in graphene, and FIG. The potential of the ion is received from a carbon ring having an 8-membered ring structure or a carbon ring having a 9-membered ring structure. FIG. 3 is a diagram for explaining the change in the calorific energy at an arbitrary mechanical strength. The area of ​​the gap in the graphene, a, and the area of ​​the graphene containing one gap, S (1 / S is This is a diagram explaining the relationship between the number density and the surface area.

[0018] First, as candidates for the gap with the smallest area in graphene, carbon rings with eight-membered ring structures and The lithium ion permeability of carbon rings with nine-membered ring structures was verified by first-principles calculations. The calculation was performed using the first-principles calculation software VASP, which is based on the plane wave basis pseudopotential method. .

[0019] Figure 1(A) shows the structure of an eight-membered ring structure formed in graphene, calculated by first-principles calculations. The optimal structure of the carbon ring is shown. The ring diameter of the carbon ring 301, which has an 8-membered ring structure, is a maximum of 0.427. nm, the smallest is 0.347 nm, and the elementary geometric area using a triangle is 0.105n m 2 It is.

[0020] Figure 1(B) shows the nine-membered ring structure formed in graphene obtained by first-principles calculations. The optimum structure of the carbon ring having a 9-membered ring structure is shown. The ring diameter of the carbon ring 302 is a maximum of 0.4 28 nm, the smallest is 0.422 nm, and the elementary geometric area using triangles is 0.14 9nm 2 It is.

[0021] The results of examining the lithium ion permeability for the structures shown in Figures 1(A) and 1(B) The relationship between the distance of the lithium ion from the carbon ring and the distance of the lithium ion from the carbon ring is shown in Figure 2. The horizontal axis of Figure 2 shows the change in potential energy received from the lithium ion. The vertical axis indicates the distance from the carbon ring to the lithium ion, and the vertical axis indicates the potential energy that the lithium ion receives from the carbon ring. In FIG. 2, curve 311 shows the energy of the lithium ion having an eight-membered ring structure. The curve 312 shows the change in potential energy received from the carbon ring 301, which is a lithium The change in potential energy that an ion receives from a carbon ring 302 having a nine-membered ring structure is shown. is doing.

[0022] The potential energy of the carbon ring 301 with an 8-membered ring structure is calculated based on the distance between the lithium ion and the ring. is minimal at around 0.2 nm, but as it becomes smaller, it starts to increase. A potential energy of about 1 eV is required to reach the carbon ring 301, so The ion cannot penetrate the carbon ring 301.

[0023] In contrast, in the case of the carbon ring 302 having a nine-membered ring structure, the lithium ion cannot reach the carbon ring 302. The potential energy at this time is about -0.26 eV, and the lithium ion is in the carbon ring. 302 can be easily penetrated.

[0024] In general, the potential energy for penetrating a carbon ring increases as the number of ring members in the carbon ring decreases. As the number of ring members increases, the number of ring members decreases. The number of carbon rings (gaps) in graphene must be 9 or more. Therefore, the area a of the gap needs to be larger than the straight line 401 shown in FIG.

[0025] The time it takes for lithium ions to penetrate the porous graphene is mainly due to the This is determined by the time it takes for the lithium ions in the fen plane to reach the gap.

[0026] As shown in FIG. 4A, lithium ions 103 move within the plane of graphene 102 and When the electrode 101 (or the active material 101 in the case of a power storage device) contacts the graphene 102, the electrode 101 ) is negative potential, the electrons move to the lower graphene layer (when the electrode 101 is positive potential, the electrons move to the upper graphene layer). (moving to graphene).

[0027] Lithium ions moving through the graphene 102 having gaps 104 are transported to carbon atoms having 9 or more ring members. The time it takes for the particle to reach the gap 104, which is an elementary ring, is as follows, based on the model of FIG. 4(B). is calculated as:

[0028] First, consider the diffusion of lithium ions on graphene. The distance r that a neutron can travel from point P in time t is given by two-dimensional Brownian motion. The relationship between the mean square displacement and time in the motion can be expressed as Equation 1. , D is the diffusion coefficient of lithium ions.

[0029]

number

[0030] In other words, after time t, a lithium ion at point P will be in a circle of radius r centered at point P. It can be said to exist in 5.

[0031] Next, the area (average) of graphene containing one gap 104, which is a carbon ring with 9 or more ring members, Let S be the area of ​​the lithium ion moving on the graphene until it reaches the gap 104. Let us consider the time. Note that the inverse of S (1 / S) is the time per unit area of ​​graphene 102. is the number of gaps 104 (number density of gaps).

[0032] If the time when the lithium ion at point P reaches the gap 104 is t0, then Equation 1 and From the formula for calculating the area of ​​a circle, we can derive Equation 2. That is, moving on graphene Lithium ions may reach the gap 104 after time t0 that satisfies Equation 2. The equation obtained by solving Equation 2 for time t0 is shown in Equation 3.

[0033]

number

[0034]

number

[0035] Next, consider the probability that a lithium ion reaches the gap 104 after time t. The probability that the lithium ion will subsequently reach the gap 104 is From the area S of the hole and the area a of the gap 104, it can be expressed as a / S. The probability that no lithium ions have reached the gap 104 at this time can be expressed as 1-a / S. From this, the probability that the lithium ion has not reached the gap 104 after time t can be expressed by the formula It can be expressed as 4.

[0036]

number

[0037] Therefore, after time t, the lithium ions reach the gap 104 (not on the graphene 102). a) The probability P(t) can be expressed by Equation 5.

[0038]

number

[0039] In addition, when a / S is sufficiently small, we can approximate Equation 5 as Equation 6 by Taylor expansion. It is possible.

[0040]

number

[0041] And when the lithium ion reaches the gap 104 (not on the graphene 102), If the time between the two events is t1, then the probability P(t1) is 1. Substituting Equation 3 for time t0 in Equation 6, Then, the time t1 can be expressed by Equation 7.

[0042]

number

[0043] Therefore, the lithium ions moving on the graphene 102 having the gaps 104 have an area a The time it takes for the beam to reach the gap 104 having the beam width of 0.5 mm can be calculated using Equation 7.

[0044] The diffusion coefficient D of lithium ions on the graphene surface is 1×10 -11 cm 2 / s. If the time t1 is set to a time that is sufficiently shorter than the charge / discharge time of the battery actually used, for example, 10 seconds or less, If we impose the condition, the straight line 402 in FIG. 3 is obtained from Equation 7. S takes a value below the straight line 402. Therefore, the condition of Equation 8 must be satisfied.

[0045]

number

[0046] Naturally, the higher the gap density, the shorter the time it takes for lithium ions to reach the gap. On the other hand, an increase in the number density of voids leads to a decrease in the mechanical strength of graphene. Therefore, it is necessary to set an upper limit on the number density of voids.

[0047] The mechanical strength against tension or compression in one dimension is the interfacial strength It is determined by the ratio of voids. Approximate calculation is made by using Equation 9, where U is the mechanical strength in the one-dimensional direction. It can be seen.

[0048]

number

[0049] For example, the mechanical strength of graphene in the one-dimensional direction is k times (k<1, k is the same as that of graphene without pores). To ensure the mechanical strength of the graphene, the gaps in the one-dimensional direction of the graphene must be The ratio should be (1-k) times. In other words, the ratio of the gap to the two-dimensional direction of the graphene is the (1-k) of the area S 2 This condition is the line 40 in Figure 3. 3 is determined. Since S must be equal to or greater than the value of the line 403, the condition of formula 10 is satisfied. It is necessary to add. Note that line 403 shows the case where k=2 / 3.

[0050]

number

[0051] Although FIG. 3, Equation 9, and Equation 10 show the case where the graphene is one layer, Even when a plurality of graphenes are stacked, the contents disclosed in this embodiment are taken into consideration. It is possible to determine this.

[0052] In addition, the gaps in graphene are not limited to carbon rings, but may be selected from oxygen, nitrogen, and sulfur. It may have a cyclic compound structure containing one or more elements and carbon.

[0053] In this way, the area a and the area S are defined as the area surrounded by the lines 401 to 403 shown in FIG. By setting the gap size and the The number density of the gaps can be optimized.

[0054] By applying the graphene-covered electrode or active material to a power storage device, the charging and discharging of the power storage device can be improved. It is possible to improve the speed. It also increases the storage capacity per unit weight of the storage device. In addition, the cycle characteristics of the power storage device can be improved.

[0055] This embodiment mode can be implemented in appropriate combination with other embodiment modes.

[0056] (Embodiment 2) In this embodiment, a graphene having 1 to 50 layers on the surface of a silicon particle is used. An example of forming a graphene layer will be described. First, graphite is oxidized to form graphite oxide. By applying ultrasonic vibration to the nanoparticles, graphene oxide is obtained. 2. Alternatively, commercially available graphene oxide may be used.

[0057] Next, graphene oxide and silicon particles are mixed. The ratio of graphene oxide is 1:1. The content of the fluorine-containing compound is preferably 1% to 5% by weight. or in an inert gas (nitrogen or rare gas, etc.) at 150°C, preferably The graphene oxide is heated at a temperature of 200°C or higher. The higher the heating temperature, the better the reduction of the graphene oxide. This results in graphene with high purity (i.e., low concentrations of elements other than carbon). Oh, it is known that graphene oxide is reduced at 150°C.

[0058] In order to increase the electronic conductivity of the resulting graphene, a high-temperature treatment is preferable. For example, at a heating temperature of 100°C (for 1 hour), the resistivity of multi-layer graphene is about 240 MΩcm. However, at a heating temperature of 200°C (1 hour), it was 4 kΩcm, and at 300°C (1 hour), it was 2 The resistance becomes 0.8Ωcm.

[0059] The graphene oxide formed on the surface of the silicon particles in this way is reduced, and graphene At that time, adjacent graphene bonds to each other to form a larger mesh or sheet-like structure. The graphene thus formed can be used as a The gaps have a sufficient number density to allow lithium ions to pass through.

[0060] The silicon particles that have undergone the above treatment are then dissolved in a suitable solvent (water, chloroform, or N,N-dimeth- Dylformamide (DMF) and N-methylpyrrolidone (NMP The slurry is then dispersed in a polar solvent such as ), which is preferably a polar solvent, to obtain a slurry. can be created.

[0061] FIG. 5 is a schematic diagram showing the structure of a coin-type secondary battery. As shown in FIG. The secondary battery includes an anode 204, a cathode 232, a separator 210, an electrolyte (not shown), and a housing 20. 6 and a housing 244. In addition, the ring-shaped insulator 220, the spacer 240, and and a washer 242.

[0062] The negative electrode 204 has a negative electrode active material layer 202 on a negative electrode current collector 200. For example, copper may be used as the negative electrode active material. The slurry may be mixed with a binder and used as the negative electrode active material layer 202 .

[0063] The material of the positive electrode current collector 228 is preferably aluminum. The slurry in which the positive electrode active material particles are mixed with a binder and a conductive additive is applied to the positive electrode current collector 228. It is sufficient to apply it on top and allow it to dry before use.

[0064] The positive electrode active material is lithium cobalt oxide, lithium iron phosphate, lithium manganese phosphate, etc. Lithium, lithium manganese silicate, lithium iron silicate, etc. can be used, but are not limited to these. The particle size of the active material particles is preferably 20 nm to 100 nm. The carbon is mixed with carbohydrates such as cellulose so that the positive electrode active material particles are coated with carbon. This treatment increases the electrical conductivity.

[0065] The electrolyte is a mixture of ethylene carbonate (EC) and diethyl carbonate (DEC). It is preferable to use a mixture solvent in which LiPF6 is dissolved, but the present invention is not limited to this.

[0066] The separator 210 may be made of an insulating material having holes (e.g., polypropylene). However, a solid electrolyte that is permeable to lithium ions may also be used.

[0067] The housing 206, the housing 244, the spacer 240 and the washer 242 are made of a metal (e.g., The housing 206 and the housing 244 are made of a material such as stainless steel. and the positive electrode 232 to the outside.

[0068] The negative electrode 204, the positive electrode 232 and the separator 210 are immersed in an electrolyte, and the negative electrode 204, the positive electrode 232 and the separator 210 are immersed in an electrolyte. 2, the negative electrode 204, the separator 210, the ring-shaped insulator 220, The positive electrode 232, the spacer 240, the washer 242, and the housing 244 are laminated in this order, and the housing 206 and a housing 244 are pressure-bonded to form a coin-type secondary battery.

[0069] This embodiment mode can be implemented in appropriate combination with other embodiment modes.

[0070] (Embodiment 3) In this embodiment, one or more layers of graphene are formed on the surface of a silicon active material layer formed on a current collector. An example of forming a graphene layer having 50 or less layers will be described. First, a graphene oxide layer is formed. The oxidized gram is dispersed in a solvent such as water or NMP. The solvent is preferably a polar solvent. The concentration of fen may be between 0.1 and 10 grams per liter.

[0071] The silicon active material layer together with the current collector is immersed in this solution, and then it is pulled out and dried. In addition, it is heated for 20 minutes in a reducing atmosphere such as a vacuum or an inert gas (nitrogen or rare gas, etc.). The above steps result in graphene being deposited on the surface of the silicon active material layer. A graphene layer having 50 or more layers can be formed. The graphene layer has gaps in the number density as explained above, so lithium ions can pass through it. Pass.

[0072] After the graphene layer was formed in this manner, the same process was repeated once more. In addition, a graphene layer having 1 to 50 graphene layers may be formed in the same manner. The same process may be repeated three or more times. By forming multi-layer graphene in this way, The strength of the entire graphene layer is increased.

[0073] When forming a thick graphene layer at once, the sp 2 Bond orientation disorder This causes the strength of the graphene layer to be out of proportion to its thickness. When forming a graphene layer, the sp 2 The bonds are roughly parallel to the surface of the silicon. Therefore, the thicker the graphene layer, the stronger it becomes.

[0074] This embodiment mode can be implemented in appropriate combination with other embodiment modes.

[0075] (Embodiment 4) In this embodiment, one or more layers of graphene are formed on the surface of a silicon active material layer formed on a current collector. Another example of forming a graphene layer having 50 or less layers will be described. Similarly, graphene oxide is dispersed in a solvent such as water or NMP. The concentration of graphene is 1 liter. The amount may be 0.1 to 10 g per unit.

[0076] The current collector on which the silicon active material layer is formed is placed in a solution in which graphene oxide is dispersed. Also, put a conductor that will be the negative electrode into the solution and apply an appropriate voltage (e.g. Graphene oxide is a material that is made up of graphene sheets of a certain size. Since some of the carboxyl groups are terminated with carboxyl groups (-COOH), in solutions such as water, Hydrogen ions are released from the carboxyl groups, and the graphene oxide itself becomes negatively charged. The voltage does not have to be constant. By measuring the amount of charge flowing between the layers, the graphene oxide layer attached to the silicon active material layer can be The thickness can be estimated.

[0077] Once the required thickness of graphene oxide is obtained, the current collector is removed from the solution and dried. In addition, it is heated for 20 minutes in a reducing atmosphere such as a vacuum or an inert gas (nitrogen or rare gas, etc.). The silicon oxide formed on the surface of the silicon active material is heated to a temperature of 0°C or higher. The phenes are reduced to graphene. At that time, adjacent graphenes bond together, It forms a huge mesh-like or sheet-like network.

[0078] The graphene formed as described above can be attached to the concave portions of the silicon active material even if the silicon active material has concaves and convexes. In this way, the silicon active material layer is formed on the surface of the silicon active material layer with a uniform thickness. In this way, a graphene layer having 1 to 50 phenes can be formed. The graphene layers formed by this method have the number density of gaps as explained above, so they are lithium-ion. Mu ions pass through.

[0079] After the graphene layer is formed in this manner, the graphene layer is The formation of the graphene layer by the method of the second embodiment may be performed one or more times. good.

[0080] This embodiment mode can be implemented in appropriate combination with other embodiment modes.

[0081] (Embodiment 5) The power storage device according to one embodiment of the present invention can be used as a power source for various electric devices driven by electric power. It is possible.

[0082] Specific examples of electrical devices using a power storage device according to one embodiment of the present invention include display devices, lighting devices, and Desktop or notebook personal computer, DVD (Digital Video Plays still images or videos stored on a recording medium such as a portable digital disc. Image playback devices, mobile phones, portable game consoles, personal digital assistants, electronic books, video cameras, Digital still cameras, microwave ovens and other high-frequency heating devices, electric rice cookers, electric washing machines, air conditioners Air conditioning equipment such as conditioners, electric refrigerators, electric freezers, electric refrigerator-freezers, DNA storage Examples of such equipment include refrigerators, dialysis machines, etc. The moving object that propels the vehicle is also included in the category of electrical equipment. For example, electric vehicles, hybrid cars that combine internal combustion engines and electric motors, Examples include motorized bicycles, including electrically assisted bicycles.

[0083] The above electrical equipment will be used as a power storage device (called the main power source) to cover almost all of the power consumption. The power storage device according to one embodiment of the present invention can be used for the above electric device. When the power supply from the main power source or commercial power source is stopped, the power supply is supplied to the electrical equipment. The power storage device according to one embodiment of the present invention can be used as a power storage device (referred to as an uninterruptible power supply). Alternatively, the electrical equipment may be provided with a power supply that is connected to the electrical equipment from the main power source or commercial power source. A power storage device (called an auxiliary power source) that supplies power to electrical equipment in parallel with the supply of power. The power storage device according to one embodiment of the present invention can be used as the power storage device.

[0084] FIG. 6 shows a specific configuration of the above-mentioned electric device. In FIG. 6, a display device 5000 is 5 is an example of an electric device using a power storage device 5004 according to one embodiment of the present invention. 5000 corresponds to a display device for receiving TV broadcasts, and includes a housing 5001, a display unit 5002, a speaker The power storage device 500 according to one embodiment of the present invention includes a power storage unit 5003 and a power storage device 5004. 4 is provided inside a housing 5001. The display device 5000 receives power from a commercial power source. The power can be supplied or stored in the power storage device 5004 can be used. Therefore, even when power cannot be supplied from a commercial power source due to a power outage or the like, the present invention can be used in one embodiment. By using the power storage device 5004 as an uninterruptible power supply, the display device 5000 can be used It becomes possible.

[0085] The display unit 5002 may be a liquid crystal display device, an emitting device having light emitting elements such as organic EL elements in each pixel, or the like. Device, electrophoretic display device, DMD (Digital Micromirror Devi ce), PDP (Plasma Display Panel), FED (Field A semiconductor display device such as a 3D Emission Display can be used.

[0086] In addition, display devices are used for TV broadcast reception, personal computers, advertising displays, etc. , all display devices for displaying information are included.

[0087] In FIG. 6, a stationary lighting device 5100 includes a power storage device 510 according to one embodiment of the present invention. 5101, a light source 5102, and a housing 5101. 6, the power storage device 5103 is disposed in a housing 5101. 5102 is provided inside a ceiling 5104. However, the power storage device 5103 may be provided inside the housing 5101. The power supply device 100 can receive power from a commercial power source, or can store power in a power storage device 5103. Therefore, when power is not supplied from the commercial power source due to a power outage, etc., The power storage device 5103 of one embodiment of the present invention can be used as an uninterruptible power supply even when the power storage device 5103 is not connected to the power source. Then, the lighting device 5100 becomes available for use.

[0088] In addition, FIG. 6 illustrates a lighting device 5100 that is installed on a ceiling 5104. However, in the power storage device of one embodiment of the present invention, in addition to the ceiling 5104, for example, the side wall 5105, the floor 51 06, it can be used for a fixed type lighting device installed in a window 5107, etc., or a tabletop type The present invention can also be used in lighting devices.

[0089] In addition, the light source 5102 may be an artificial light source that artificially obtains light using electricity. Specifically, incandescent lamps, fluorescent lamps and other discharge lamps, light emitting diodes (LEDs) and organic electroluminescence (EL) elements The element is an example of the artificial light source.

[0090] In FIG. 6, an air conditioner having an indoor unit 5200 and an outdoor unit 5204 is 5 is an example of an electric device including a power storage device 5203 according to one embodiment of the invention. The electronic device 5200 includes a housing 5201, an air outlet 5202, a power storage device 5203, and the like. Although the power storage device 5203 is provided in the indoor unit 5200, 5203 may be provided in the outdoor unit 5204. Alternatively, the indoor unit 5200 and the outdoor unit 5204 may be provided in the indoor unit 5200 and the outdoor unit 5204. A power storage device 5203 may be provided in both the power supply 5202 and the power supply 5204. The power can be supplied from a commercial power source, or the power stored in the power storage device 5203 can be used. In particular, the power storage device 5203 can be used in both the indoor unit 5200 and the outdoor unit 5204. If a power outage is detected, the power supply will continue to function even if the power supply is not available from the commercial power source. The power storage device 5203 according to one embodiment of the present invention can be used as an uninterruptible power supply, The use of the scrubber will be available.

[0091] In Figure 6, we take an example of a separate type air conditioner consisting of an indoor unit and an outdoor unit. The figure shows an integrated air conditioner that has both the indoor and outdoor functions in a single housing. The power storage device of one embodiment of the present invention can also be used for the partitioner.

[0092] In FIG. 6, an electric refrigerator-freezer 5300 uses a power storage device 5304 according to one embodiment of the present invention. Specifically, the electric refrigerator-freezer 5300 includes a housing 5301, a refrigerator 6, the power storage device 5304 and the like are included. The electric refrigerator-freezer 5300 is a commercial refrigerator-freezer. It can receive power from a power source, or can use the power stored in the power storage device 5304. Therefore, even when power cannot be supplied from commercial power sources due to a power outage, By using the power storage device 5304 of one embodiment of the present invention as an uninterruptible power supply, The 5,300 storehouses will be available for use.

[0093] Among the above-mentioned electrical appliances, high-frequency heating devices such as microwave ovens, electric rice cookers, etc. The equipment requires high power for a short period of time. Therefore, the equipment supplements the power that cannot be supplied by commercial power sources. By using a power storage device according to one embodiment of the present invention as an auxiliary power source for It can prevent the commercial power breaker from tripping during use.

[0094] In addition, during periods when electrical equipment is not being used, especially during periods when the total amount of power that can be supplied by the commercial power supplier is low, During times when the proportion of electricity actually used (called the electricity usage rate) is low, By storing power in the device, it is possible to prevent high power usage outside of the above time periods. For example, in the case of the electric refrigerator-freezer 5300, when the temperature is low, the refrigerator compartment door 530 2. During the night when the freezer door 5303 is not opened or closed, electricity is stored in the power storage device 5304. Then, as the temperature rises, the refrigerator door 5302 and the freezer door 5303 are opened and closed. By using the power storage device 5304 as an auxiliary power source during the daytime, the daytime power usage rate can be kept low.

[0095] This embodiment mode can be implemented in appropriate combination with any of the above embodiment modes. [Explanation of symbols]

[0096] 101 Electrode 102 Graphene 103 Lithium-ion 104 Gap 105 yen 200 Negative electrode current collector 202 Negative electrode active material layer 204 Negative electrode 206 Case 210 Separator 220 Ring-shaped insulator 228 Positive electrode current collector 230 Cathode active material layer 232 Positive electrode 240 Spacer 242 Washer 244 Case 301 Carbocycles 302 Carbocycles 311 Curve 312 curve 401 straight line 402 straight line 403 straight line 5000 display devices 5001 Case 5002 Display section 5003 Speaker section 5004 Electricity storage device 5100 Lighting equipment 5101 Case 5102 Light source 5103 Energy storage devices 5104 Ceiling 5105 Side wall 5106 Bed 5107 Windows 5200 indoor unit 5201 Case 5202 Ventilator 5203 Energy storage devices 5204 Outdoor unit 5300 Electric refrigerator-freezer 5301 Case 5302 Refrigerator door 5303 Freezer door 5304 Energy storage devices

Claims

[Claim 1] Graphene having gaps, the gap is a carbon ring having 9 or more ring members; The area S of the graphene including one gap is Formula 1 and Formula 2 are satisfied, and the area a of the gap is 0.149 nm ２ That's all about graphene. [0010] [0025] (In the formula, D represents the diffusion coefficient of lithium ions, t1 represents the time it takes for ions on the graphene to reach the gaps, and k represents the ratio of the mechanical strength of the graphene having the gaps to the mechanical strength of graphene without gaps.)

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