Active material for secondary battery, electrode for secondary battery, secondary battery, and aircraft

Abstract

SOLUTION: To provide an active material for a secondary battery, which is used as an active material for a secondary battery, the active material containing at least any compound or salt thereof represented by general formula (1), general formula (2), general formula (3) or general formula (4) containing an oligomer in which a plurality of phenazine structures are bonded, and also provide a secondary battery having a positive electrode active material layer containing a positive electrode active material, a negative electrode active material layer containing a negative electrode active material, and an electrolyte, in which the positive electrode active material or the negative electrode active material contains the active material for a secondary battery.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an active material for a secondary battery, an electrode for a secondary battery, a secondary battery, and an aircraft. [Background technology]

[0002] Patent Document 1 discloses an electrode active material for non-aqueous secondary batteries, which is made of a compound in which a naphthazarin skeleton is condensed with a non-conjugated ring such as a dithiin ring, as an organic material exhibiting redox activity. [Prior art document] [Patent documents] [Patent Document 1] JP 2018-085243 A Summary of the Invention

[0003] In a first aspect of the present invention, there is provided an active material for a secondary battery, which is used as an active material for a secondary battery. The active material contains at least one compound represented by the following general formula (1), general formula (2), general formula (3) and general formula (4) or a salt thereof.

[0004] [General formula (1)] [ka] In the general formula (1), R 11 , R at the end 12 , R 13 and R 14 each independently represents an oxygen atom, a group represented by -OM, a hydrogen atom, or an organic group; M represents a hydrogen atom, or a monovalent or divalent metal atom; when M is a divalent metal atom, two adjacent R 11 ~R 14 are linked to each other to form a ring represented by -OMO-, a double line represented by a solid line and a dashed line represents a single bond or a double bond, a1 represents an integer of 2 to 10, b1 and c1 each independently represent an integer of 1 to 3, and when b1 and c1 are 2 or 3, R 13 and R 14 are the same or different, R 13 and R14 At least four of the are oxygen atoms or groups represented by -OM.

[0005] [General formula (2)] [ka] In the general formula (2), R 21 , R at the end 22 , R 23 and R 24 each independently represents an oxygen atom, a group represented by -OM, a hydrogen atom, or an organic group; M represents a hydrogen atom, or a monovalent or divalent metal atom; when M is a divalent metal atom, two adjacent R 21 ~R 24 are linked together to form a ring represented by -OMO-, L is a divalent linker including a direct bond, an aromatic group, a double bond, or a triple bond, a solid line and a dashed line represent a single bond or a double bond, a2 is an integer of 2 to 10, b2 and c2 are each independently an integer of 1 to 3, and when b2 and c2 are 2 or 3, R 23 and R 24 are the same or different, R 23 and R 24 At least four of the are oxygen atoms or groups represented by -OM.

[0006] [General formula (3)] [ka] In the general formula (3), R 31 , R at the end 32 , R 33 ~R 36 each independently represents an oxygen atom, a group represented by -OM, a hydrogen atom, or an organic group; M represents a hydrogen atom, or a monovalent or divalent metal atom; when M is a divalent metal atom, two adjacent R 31 ~R 36are linked to each other to form a ring represented by -OMO-, L is a divalent linker including a direct bond, an aromatic group, a double bond, or a triple bond, a double line represented by a solid line and a dashed line represents a single bond or a double bond, a3 is an integer of 1 to 5, b31, b32, c31, and c32 are each independently an integer of 1 to 3, and when b31, b32, c31, and c32 are 2 or 3, R 33 , R 34 , R 35 and R 36 are the same or different, R 33 and R 34 At least four of the above and R 35 and R 36 At least four of the are oxygen atoms or groups represented by -OM.

[0007] [General formula (4)] [ka] In the general formula (4), R 41 , R 43 and R 44 each independently represents an oxygen atom, a group represented by -OM, a hydrogen atom, or an organic group; M represents a hydrogen atom, or a monovalent or divalent metal atom; when M is a divalent metal atom, two adjacent R 41 , R 43 and R 44 are linked to each other to form a ring represented by -OMO-, L is a k-valent linker including a direct bond or an aromatic group, a double bond or a triple bond, a solid line and a dashed double line represent a single bond or a double bond, a4 is an integer of 1 to 5, b4 and c4 are each independently an integer of 1 to 3, and when b4 and c4 are 2 or 3, R 43 and R 44 are the same or different, R 43 and R 44 At least four of the groups are oxygen atoms or groups represented by -OM, and k is an integer of 2 or more.

[0008] The compound may be any of the compounds represented by the following general formulas (5) to (7).

[0009] [General formula (5)] [ka] In the general formula (5), R 101 , R at the end 102 , R 103 ~R 108 each independently represents an oxygen atom, a group represented by -OM, a hydrogen atom, or an organic group; M represents a hydrogen atom, or a monovalent or divalent metal atom; when M is a divalent metal atom, two adjacent R 101 ~R 108が R 103 ~R 108 At least four of the groups are oxygen atoms or groups represented by -OM, and a1 is an integer of 2 to 10.

[0010] [General formula (6)] [ka] In the general formula (6), R 201 , R at the end 202 , R 203 ~R 208 each independently represents an oxygen atom, a group represented by -OM, a hydrogen atom, or an organic group; M represents a hydrogen atom, or a monovalent or divalent metal atom; when M is a divalent metal atom, two adjacent R 201 ~R 208 are linked together to form a ring represented by -OMO-, L is a direct bond or a divalent linker containing an aromatic group, a double bond or a triple bond, the double line represented by a solid line and a dashed line represents a single bond or a double bond, R 203 ~R 208 At least four of the groups are oxygen atoms or groups represented by -OM, and a2 is an integer of 2 to 10.

[0011] [General formula (7)] [ka] In the general formula (7), R 301 , R at the end 302 , R 303 ~R 314 each independently represents an oxygen atom, a group represented by -OM, a hydrogen atom, or an organic group; M represents a hydrogen atom, or a monovalent or divalent metal atom; when M is a divalent metal atom, two adjacent R 301 ~R 314 are linked together to form a ring represented by -OMO-, L is a direct bond or a divalent linker containing an aromatic group, a double bond or a triple bond, the double line represented by a solid line and a dashed line represents a single bond or a double bond, R 303 ~R 308 At least four of the above and R 309 ~R 314 At least four of the groups are oxygen atoms or groups represented by -OM, and a3 is an integer of 1 to 5.

[0012] [General formula 8] [ka] In the general formula (8), R 401 , R 403 ~R 408 each independently represents an oxygen atom, a group represented by -OM, a hydrogen atom, or an organic group; M represents a hydrogen atom, or a monovalent or divalent metal atom; when M is a divalent metal atom, two adjacent R 401 and R 403 ~R 408 are linked together to form a ring represented by -OMO-, L is a direct bond or a k-valent linker including an aromatic group, a double bond or a triple bond, the solid line and the dashed line represent a single bond or a double bond, R 403 ~R 408 At least four of the groups are oxygen atoms or groups represented by -OM, a4 is an integer of 1 to 5, and k is an integer of 2 or greater.

[0013] The compound may be a compound represented by the following general formula (9).

[0014] [General formula (9)] [ka] In the general formula (9), R 501 , R at the end 502 , R 503 ~R 508 each independently represents an oxygen atom, a group represented by -OM, a hydrogen atom, or an organic group; M represents a hydrogen atom, or a monovalent or divalent metal atom; when M is a divalent metal atom, two adjacent R 501 ~R 508 are linked to each other to form a ring represented by -OMO-, a double line represented by a solid line and a dashed line represents a single bond or a double bond, a51 and a53 each independently represent an integer of 1 to 5, b51, b52, b53, c51, c52 and c53 each independently represent an integer of 1 to 3, and when b51, b53, c51 and c53 are 2 or 3, R 503 , R 504 , R 507 and R 508 are the same or different, R 503 and R 504 At least four of the above and R 507 and R 508 At least four of the above are oxygen atoms or groups represented by -OM, n and m are each an integer of 1 to 3, and the sum of n and b52, and the sum of m and c52 are each 4 or less.

[0015] In the secondary battery active material, the compound may be symmetric.

[0016] In the above active material for a secondary battery, L may be a direct bond or an organic group including an arylene group, a heterocyclic group, an alkenylene group, or an alkynylene group.

[0017] In the above-mentioned active material for secondary batteries, the above-mentioned compound may be at least any one of the compounds shown below, or a completely reduced product or a partially reduced product thereof. [ka] [ka] [ka] [ka] [ka]

[0018] In the above active material for a secondary battery, M may be H, Li, Na, K, Mg or Ca.

[0019] In a second aspect of the present invention, there is provided an electrode for a secondary battery, the electrode for a secondary battery comprising the active material for a secondary battery.

[0020] In a third aspect of the present invention, there is provided a secondary battery, the secondary battery having a positive electrode active material layer including a positive electrode active material, a negative electrode active material layer including a negative electrode active material, and an electrolyte, wherein the positive electrode active material or the negative electrode active material includes the active material for secondary batteries described above.

[0021] In the secondary battery, the positive electrode active material may include the active material for secondary batteries.

[0022] The secondary battery may be a non-aqueous secondary battery.

[0023] In a fourth aspect of the present invention, there is provided an aircraft, which may include the secondary battery and a thrust generating device that generates thrust by utilizing the electrical energy stored in the secondary battery.

[0024] The above summary of the invention does not list all of the features of the present invention. Also, subcombinations of these features may also be inventions. [Brief description of the drawings]

[0025] [Figure 1] 1 shows a schematic diagram of an example of the system configuration of an aircraft 100. [Diagram 2] An example of a power storage cell 112 is shown diagrammatically. [Diagram 3] 4 shows the change in capacity retention rate in a charge / discharge test of the secondary battery of the present embodiment. [Figure 4] 4 shows the change in capacity retention rate in a charge / discharge test of the secondary battery of the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] The present invention will be described below through embodiments of the invention, but the following embodiments do not limit the scope of the invention according to the claims. Furthermore, not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention.

[0027] 1 illustrates an example of a system configuration of an aircraft 100. In this embodiment, the aircraft 100 includes a storage battery 110, a power control circuit 120, one or more electric motors 130, one or more propellers 140, one or more sensors 150, and a control device 160. In this embodiment, the storage battery 110 includes one or more storage cells 112.

[0028] In this embodiment, the flying object 100 flies using electrical energy stored in the storage battery 110. Examples of the flying object 100 include an airplane, an airship or a balloon, a helicopter, a drone, and the like.

[0029] In this embodiment, the storage battery 110 receives electric energy from an external charging device (not shown) via the power control circuit 120, and stores the electric energy in one or more storage cells 112. In addition, the storage battery 110 supplies the electric energy stored in the one or more storage cells 112 to the electric motor 130 via the power control circuit 120.

[0030] In this embodiment, the power storage cell 112 stores electric energy (sometimes referred to as charging the power storage cell 112). The power storage cell 112 also releases the stored electric energy (sometimes referred to as discharging the power storage cell 112). The power storage cell 112 may be a secondary battery. The power storage cell 112 may be a non-aqueous secondary battery.

[0031] Examples of non-aqueous secondary batteries include sodium ion secondary batteries, lithium ion secondary batteries, lithium metal secondary batteries, lithium air secondary batteries, lithium sulfur secondary batteries, magnesium ion secondary batteries, aluminum ion secondary batteries, etc. Furthermore, a lithium ion secondary battery, which is one aspect of a non-aqueous secondary battery, may be a concept that includes a non-aqueous lithium ion secondary battery using a non-aqueous electrolyte and an all-solid-state lithium ion secondary battery using a solid electrolyte.

[0032] For example, a material that can store a large amount of charge per unit volume is often selected as an active material for a secondary battery mounted on a vehicle. On the other hand, in this embodiment, the storage cell 112 is mounted on the aircraft 100. Therefore, it is preferable that the active material used for the storage cell 112 is a material that can store a large amount of charge per unit mass.

[0033] The mass energy density of the storage cell 112 is preferably 500 [Wh / kg-storage cell] or more, more preferably 550 [Wh / kg-storage cell] or more, more preferably 600 [Wh / kg-storage cell] or more, even more preferably 650 [Wh / kg-storage cell] or more, and even more preferably 700 [Wh / g-storage cell] or more. This provides a storage cell that is particularly suitable for use as a power source for an aircraft.

[0034] The volumetric energy density of the storage cell 112 is 300 [Wh / m 3 - Storage cell] 1200 [Wh / m 3 - Storage cell] or less, 400 [Wh / m 3 - Storage cell] 1000 [Wh / m 3 When the storage cell 112 is mounted on the aircraft 100 as part of the power source of the aircraft 100, the volumetric energy density of the storage cell 112 may be 600 [Wh / m 3 - Storage cell] or less, 800 [Wh / m 3 -storage cell] or less.

[0035] The storage cell 112 may have a mass energy density within the above numerical range and a volume energy density within the above numerical range. This allows the storage cell, which is relatively difficult to use as a power source for a vehicle, to be used as a power source for an aircraft. The details of the storage cell 112 will be described later.

[0036] In this embodiment, the power control circuit 120 controls the input and output of power of the storage battery 110. The power control circuit 120 may control the input and output of power of the storage battery 110 based on an instruction from the control device 160. The power control circuit 120 includes, for example, a plurality of switching elements that operate based on a control signal from the control device 160.

[0037] In this embodiment, the electric motor 130 receives electric energy from the storage battery 110 via the power control circuit 120. The electric motor 130 rotates the propeller 140 using the electric energy received from the storage battery 110. In this way, the electric motor 130 can generate propulsion force for the flying object 100 using the electric energy stored in the storage cell 112.

[0038] In this embodiment, the sensor 150 measures various physical quantities related to the position and attitude of the flying object 100. Examples of sensors for measuring various physical quantities related to the position and attitude of the flying object 100 include a GPS signal receiver, an acceleration sensor, an angular acceleration sensor, and a gyro sensor. The sensor 150 may measure various physical quantities related to the state of the storage battery 110. Examples of sensors for measuring various physical quantities related to the state of the storage battery 110 include a temperature sensor, a current sensor, and a voltage sensor.

[0039] In this embodiment, the control device 160 controls the flying object 100. The control device 160 may control the input and output of power to the storage battery 110 by controlling the power control circuit 120. For example, the control device 160 controls the output current, output voltage, input current, input voltage, etc. of the storage battery 110. This allows the control device 160 to control the position and attitude of the flying object 100. The control device 160 may control the position and attitude of the flying object 100 by controlling the power control circuit 120 based on the output from the sensor 150.

[0040] The storage battery 110 may be an example of a secondary battery. The storage cell 112 may be an example of a secondary battery. The electric motor 130 may be an example of a propulsion force generating device.

[0041] 2 is a schematic diagram of an example of the power storage cell 112. In this embodiment, the power storage cell 112 will be described in detail by taking as an example a case in which the power storage cell 112 is a coin-type non-aqueous secondary battery.

[0042] [Energy storage cell] In this embodiment, the energy storage cell 112 includes a positive electrode case 212, a negative electrode case 214, a sealant 216, and a metal spring 218. The energy storage cell 112 also includes a positive electrode 220, a separator 230, a negative electrode 240, and an electrolyte 250. In this embodiment, the positive electrode 220 includes a positive electrode current collector 222 and a positive electrode active material layer 224. In this embodiment, the negative electrode 240 includes a negative electrode current collector 242 and a negative electrode active material layer 244.

[0043] In this embodiment, by assembling the positive electrode case 212 and the negative electrode case 214, a space is formed inside the positive electrode case 212 and the negative electrode case 214. A metal spring 218, a positive electrode 220, a separator 230, a negative electrode 240, and an electrolyte 250 are accommodated inside the space formed by the positive electrode case 212 and the negative electrode case 214. The positive electrode 220, the separator 230, and the negative electrode 240 are fixed inside the positive electrode case 212 and the negative electrode case 214 by the repulsive force of the metal spring 218.

[0044] The positive electrode case 212 and the negative electrode case 214 are made of, for example, a conductive material having a disk-like thin plate shape. In this embodiment, the sealant 216 seals a gap formed between the positive electrode case 212 and the negative electrode case 214. The sealant 216 includes an insulating material. The sealant 216 insulates the positive electrode case 212 and the negative electrode case 214.

[0045] [Positive electrode] In this embodiment, the positive electrode current collector 222 holds the positive electrode active material layer 224. Examples of the material of the positive electrode current collector 222 include aluminum, stainless steel, nickel, titanium, and alloys thereof. Examples of the shape of the positive electrode current collector 222 include foil, mesh, punched metal, and expanded metal. The thickness of the positive electrode current collector 222 is not particularly limited, but is preferably 5 to 200 μm. The thickness of the positive electrode current collector 222 may be 6 to 20 μm.

[0046] In this embodiment, the positive electrode active material layer 224 is formed on at least one surface of the positive electrode current collector 222. The thickness of the positive electrode active material layer 224 may be 1 to 300 μm, or may be 2 to 200 μm, per surface of the positive electrode current collector 222. The positive electrode active material layer 224 contains, for example, a positive electrode active material and a binding agent (sometimes referred to as a binder). The positive electrode active material layer 224 may contain a conductive assistant.

[0047] In one embodiment, the positive electrode active material layer 224 is formed by applying a paste containing materials constituting the positive electrode active material layer 224 and an organic solvent onto at least one surface of the positive electrode current collector 222, and drying the paste. The type of the organic solvent is not particularly limited, but an example of the organic solvent is N-methylpyrrolidone (NMP). In another embodiment, the positive electrode active material layer 224 is formed by mixing materials constituting the positive electrode active material layer 224, forming the mixture into a sheet, and pressing the sheet-like mixture onto at least one surface of the positive electrode current collector 222.

[0048] The positive electrode active material layer 224 may contain, as a positive electrode active material, a heterocyclic compound containing one or more pyrazine rings and two or more benzene rings, or a salt or derivative thereof. The heterocyclic compound may be a compound containing one or more phenazine structures. The phenazine structure (i) contains one pyrazine ring and two benzene rings, and (ii) has a structure in which each of the two benzene rings is connected to the pyrazine ring by sharing one carbon-carbon bond of the pyrazine ring with the pyrazine ring. The pyrazine ring may be substituted with any functional group or may not be substituted. The benzene ring may be substituted with any functional group or may not be substituted.

[0049] The heterocyclic compound preferably contains a structure in which at least four oxygen atoms are bonded to the benzene ring. This allows the heterocyclic compound to store more charge even with a small molecular weight. As a result, by using the heterocyclic compound as a positive electrode active material, a storage cell with a large energy density per unit mass of the storage cell can be obtained.

[0050] The heterocyclic compound preferably has a structure in which an even number of oxygen atoms, 4 or more, are bonded to the benzene ring.

[0051] The positive electrode active material layer 224 may contain phenazines as a positive electrode active material. The phenazines are preferably compounds having at least four oxygen atoms bonded to a benzene ring contained in a phenazine structure. As described above, this allows a storage cell with a large energy density per unit mass of the storage cell to be obtained.

[0052] The phenazines are preferably compounds having an even number of oxygen atoms, 4 or more, bonded to the benzene ring. The phenazines may be compounds having an even number of oxygen atoms, 4 or more and 8 or less, bonded to the benzene ring. This improves the chemical stability of the heterocyclic compound.

[0053] The positive electrode active material layer 224 may contain an oligomer in which a plurality of phenazine structures are bonded together as a positive electrode active material. The oligomer may be an oligomer in which a plurality of phenazine structures are bonded together via a linker. This suppresses dissolution of the positive electrode active material in the electrolyte during charging and discharging, thereby improving the cycle performance of the secondary battery.

[0054] The positive electrode active material is, for example, a heterocyclic compound containing one or more pyrazine rings and two or more benzene rings, or a salt or derivative thereof. The positive electrode active material is, for example, a heterocyclic compound containing one or more pyrazine rings and two or more benzene rings, or a salt or derivative thereof, as a main component.

[0055] The above-mentioned heterocyclic compounds or their salts or derivatives, phenazines and their oligomers are, for example, included in any of the reaction starting materials, products and intermediate products in at least the discharge reaction of the battery electrode reaction. The details of the phenazines oligomers or their salts or derivatives that can be used as the positive electrode active material will be described later.

[0056] The positive electrode active material is not limited to the above heterocyclic compounds. When the power storage cell 112 is a lithium ion secondary battery or a lithium metal secondary battery, another example of the positive electrode active material is LiMnO 2 , LiNiO 2、LiCoO 2 、Li(Mn x Would 1-x )OR 2 、Li(Mn x No 1-x )OR 2 、Li(Ni y No 1-y )OR 2 、Li(Mn x Would y No 1-x-y )OR 2 Children's Life;Li 2 MnO 3 -LiNiO 2 、Li 2 MnO 3 -LiCoO 2 、Li 2 MnO 3 -Li(Ni y No 1-y )OR 2 Li 2 MnSiO 4 、Li 2 NiSiO 4 、Li 2 CoSiO 4 、Li 2 (Mn x Would 1-x )SiO 4 、Li 2 (Mn x No 1-x )SiO 4 、Li 2 (Would y No 1-y )SiO 4 、Li 2 (Mn x Would y No 1-x-y )SiO 4 LiMnBO, LiMnBO 3 、LiNiBO 3 、LiCoBO 3 、Li(Mn x Would 1-x )BO 3 、Li(Mn x No 1-x )BO 3 、Li(Ni y No 1-y)BO 3 , Li(Mn x Ni y Co 1-x-y )BO 3 borates such as; V 2 O 5 ; LiV 3 O 6 ; MnO, etc. may be mentioned. In the above formula, 0 < x < 1, 0 < y < 1, and 0 < x + y < 1. These cathode active materials may be used alone or two or more cathode active materials may be combined.

[0057] When the power storage cell 112 is a sodium ion secondary battery, as another example of the cathode active material, NaFeO 2 , NaNiO 2 , NaCoO 2 , NaMnO 2 , NaVO 2 , Na(Ni X Mn 1-X )O 2 , Na(Fe X Mn 1-X )O 2 , NaVPO 4 F, Na 2 FePO 4 F, Na 3 V 2 (PO 4 ) 3 etc. may be mentioned. In the above formula, 0 < x < 1. These cathode active materials may be used alone or two or more cathode active materials may be combined.

[0058] In the present embodiment, the binder binds the materials constituting the cathode active material layer 224 (for example, the cathode active material, the conductive assistant, etc.) and maintains the electrode shape of the cathode 220. The type of the binder is not particularly limited, but examples of the binder include polyvinylidene fluoride (PVDF), polytetrafluoroethylene, polyacrylic acid, styrene-butadiene rubber, etc.

[0059] In this embodiment, the conductive assistant reduces the resistance of the positive electrode 220. The type of conductive assistant is not particularly limited as long as it has the desired electronic conductivity, and an example of the conductive assistant is a carbon material. Examples of the carbon material include graphite, carbon black (e.g., acetylene black, ketjen black, etc.), coke, amorphous carbon, carbon fiber, carbon nanotube, graphene, etc. These conductive assistants may be used alone, or two or more types of conductive assistants may be combined.

[0060] When the positive electrode active material layer 224 does not contain a conductive assistant, the content of the positive electrode active material in the positive electrode active material layer 224 is preferably 40 to 99 mass%, more preferably 70 to 97 mass%, and even more preferably 80 to 95 mass%. The content of the binder in the positive electrode active material layer 224 is preferably 1 to 60 mass%, more preferably 3 to 30 mass%, and even more preferably 5 to 20 mass%.

[0061] When the positive electrode active material layer 224 contains a conductive assistant, the content of the conductive assistant in the positive electrode active material layer 224 is preferably 0.2 to 20 mass%, more preferably 1 to 10 mass%, and even more preferably 2 to 6 mass%. In this case, the content of the positive electrode active material in the positive electrode active material layer 224 is preferably 60 to 98 mass%, more preferably 70 to 96 mass%, and even more preferably 80 to 94 mass%. In addition, the content of the binder in the positive electrode active material layer 224 is preferably 1.8 to 39.8 mass%, more preferably 3 to 29 mass%, and even more preferably 4 to 18 mass%.

[0062] The content of the binder in the positive electrode active material layer 224 may be 1 to 20 mass %, 2 to 10 mass %, or 3 to 6 mass %. In this case, the remainder of the positive electrode active material layer 224 may be a positive electrode active material, or a mixture of a positive electrode active material and a conductive assistant.

[0063] [Separator] In this embodiment, the separator 230 separates the positive electrode 220 and the negative electrode 240. The separator 230 secures ion conductivity between the positive electrode 220 and the negative electrode 240, for example, by holding an electrolyte. Examples of the material of the separator 230 include polyethylene, polypropylene, an ethylene-propylene copolymer, glass, and a composite of these. Examples of the shape of the separator 230 include a microporous film, a nonwoven fabric, and a filter. The thickness of the separator 230 is not particularly limited, but is preferably 10 to 50 μm. The opening ratio of the separator 230 is not particularly limited, but is preferably 30 to 70%.

[0064] [Negative electrode] In this embodiment, the negative electrode current collector 242 holds the negative electrode active material layer 244. Examples of the material of the negative electrode current collector 242 include copper, aluminum, stainless steel, nickel, titanium, and alloys thereof. The negative electrode current collector 242 may include a resin support layer and a metal layer disposed on the surface of the support layer. Examples of the resin include polyethylene, polypropylene, polyethylene terephthalate, and polyimide. The metal layer may be a layer made of copper, aluminum, stainless steel, nickel, titanium, or an alloy thereof. The metal layer may include a layer made of copper, aluminum, stainless steel, nickel, titanium, or an alloy thereof. The metal layer may be a foil or a plating layer.

[0065] When lithium metal is used as the negative electrode active material, the lithium metal can also function as the current collector. Therefore, when the power storage cell 112 is a lithium metal secondary battery, the power storage cell 112 does not need to include the negative electrode current collector 242.

[0066] The shape of the negative electrode current collector 242 can be, for example, foil, mesh, punched metal, expanded metal, etc. The thickness of the negative electrode current collector 242 is not particularly limited, but may be 5 to 200 μm. The thickness of the negative electrode current collector 242 is preferably 6 to 20 μm.

[0067] In this embodiment, the negative electrode active material layer 244 is formed on at least one surface of the negative electrode current collector 242. The thickness of the negative electrode active material layer 244 may be 1 to 300 μm, or may be 2 to 200 μm, per surface of the negative electrode current collector 242. The negative electrode active material layer 244 contains, for example, a negative electrode active material and a binder. The negative electrode active material layer 244 may contain a conductive assistant.

[0068] In one embodiment, the negative electrode active material layer 244 is formed by applying a paste containing materials constituting the negative electrode active material layer 244 and an organic solvent onto at least one surface of the negative electrode current collector 242, and drying the paste. The type of the organic solvent is not particularly limited, but an example of the organic solvent is N-methylpyrrolidone (NMP). In another embodiment, the negative electrode active material layer 244 is formed by mixing materials constituting the negative electrode active material layer 244, forming the mixture into a sheet, and pressing the sheet-like mixture onto at least one surface of the negative electrode current collector 242.

[0069] The negative electrode active material layer 244 may contain, as a negative electrode active material, a heterocyclic compound containing one or more pyrazine rings and two or more benzene rings, or a salt or derivative thereof. The heterocyclic compound may be a compound containing one or more phenazine structures. The phenazine structure (i) contains one pyrazine ring and two benzene rings, and (ii) has a structure in which each of the two benzene rings is connected to the pyrazine ring by sharing one carbon-carbon bond of the pyrazine ring with the pyrazine ring. The pyrazine ring may be substituted with any functional group or may not be substituted. The benzene ring may be substituted with any functional group or may not be substituted.

[0070] Similar to the heterocyclic compounds described in relation to the positive electrode active material layer 224, the heterocyclic compounds that can be used in the negative electrode active material layer 244 are preferably compounds having at least four oxygen atoms bonded to the benzene ring. The heterocyclic compounds are preferably compounds having an even number of oxygen atoms, 4 or more, bonded to the benzene ring. The heterocyclic compounds may be compounds having an even number of oxygen atoms, 4 or more, bonded to the benzene ring.

[0071] The negative electrode active material layer 244 may contain phenazines as the negative electrode active material. The phenazines are preferably compounds having at least four oxygen atoms bonded to a benzene ring contained in a phenazine structure. The phenazine structure is preferably a compound having an even number of oxygen atoms, 4 or more, bonded to the benzene ring. The phenazine structure may be a compound having an even number of oxygen atoms, 4 or more and 8 or less, bonded to the benzene ring.

[0072] The negative electrode active material may include an oligomer in which a plurality of phenazine structures are bonded together. The oligomer may be an oligomer in which a plurality of phenazine structures are bonded together via a linker. This suppresses dissolution of the positive electrode active material in the secondary battery in an electrolyte, thereby improving the cycle performance of the secondary battery.

[0073] The above-mentioned heterocyclic compounds or their salts or derivatives, and phenazines and their oligomers are, for example, included in any of the reaction starting materials, products, and intermediate products in at least the charging reaction of the battery electrode reaction. The details of the phenazines oligomers or their salts or derivatives that can be used as the negative electrode active material will be described later.

[0074] The negative electrode active material is not limited to the above heterocyclic compounds. When the storage cell 112 is a lithium ion secondary battery, other examples of the negative electrode active material include (i) graphite, (ii) sinter-resistant carbon or graphitizable carbon, (iii) tin, silicon, and alloys containing these, and (iv) SiO. When materials such as (i) graphite, (ii) sinter-resistant carbon or graphitizable carbon, (iii) tin, silicon, and alloys containing these, and (iv) SiO are used as the negative electrode active material, the material may be pre-doped with lithium.

[0075] The negative electrode active material may be a lithium-containing material such as metallic lithium or a lithium alloy. For example, when the power storage cell 112 is a lithium metal secondary battery, metallic lithium is used as the negative electrode. These negative electrode active materials may be used alone, or two or more types of negative electrode active materials may be combined.

[0076] The negative electrode active material layer 244 may include lithium metal foil. This allows lithium to be supplied to the power storage cell 112. The lithium metal foil may have a thickness of 1 to 300 μm, 2 to 200 μm, or 3 to 100 μm. The thickness and / or mass of the lithium metal foil may be determined depending on the content of the positive electrode active material in the positive electrode active material layer 224.

[0077] When the power storage cell 112 is a sodium ion secondary battery, other examples of the negative electrode active material include (i) graphite, (ii) non-sinterable carbon or non-graphitizable carbon, (iii) tin, silicon and alloys containing these, and (iv) titanium oxide. The negative electrode active material may be a sodium-containing material such as metallic sodium or a sodium alloy. These negative electrode active materials may be used alone, or two or more types of negative electrode active materials may be combined.

[0078] In this embodiment, the binder binds materials (e.g., anode active material, conductive assistant, etc.) constituting the anode active material layer 244, and maintains the electrode shape of the anode 240. The type of binder is not particularly limited, but examples of the binder include polyvinylidene fluoride (PVDF), polytetrafluoroethylene, polyacrylic acid, and styrene butadiene rubber.

[0079] In this embodiment, the conductive assistant reduces the resistance of the negative electrode 240. The type of conductive assistant is not particularly limited as long as it has the desired electronic conductivity, and an example of the conductive assistant is a carbon material. Examples of the carbon material include graphite, carbon black (e.g., acetylene black, ketjen black, etc.), coke, amorphous carbon, carbon fiber, carbon nanotube, graphene, etc. These conductive assistants may be used alone, or two or more types of conductive assistants may be combined.

[0080] When the negative electrode active material layer 244 does not contain a conductive assistant, the content of the negative electrode active material in the negative electrode active material layer 244 is preferably 40 to 99 mass%, more preferably 80 to 98.5 mass%, and even more preferably 90 to 98 mass%. The content of the binder in the negative electrode active material layer 244 is preferably 1 to 60 mass%, more preferably 1.5 to 20 mass%, and even more preferably 2 to 10 mass%.

[0081] When the negative electrode active material layer 244 contains a conductive assistant, the content of the conductive assistant in the negative electrode active material layer 244 is preferably 0.1 to 20 mass%, more preferably 1 to 10 mass%, and even more preferably 2 to 5 mass%. In this case, the content of the negative electrode active material in the negative electrode active material layer 244 is preferably 40 to 98 mass%, more preferably 80 to 97 mass%, and even more preferably 90 to 96 mass%. In addition, the content of the binder in the negative electrode active material layer 244 is preferably 1.9 to 59.9 mass%, more preferably 2 to 19 mass%, and even more preferably 2 to 8 mass%.

[0082] The content of the binder in the negative electrode active material layer 244 may be 0.1 to 5 mass %, 0.2 to 3 mass %, or 0.5 to 1 mass %. In this case, the remainder of the negative electrode active material layer 244 may be the negative electrode active material, or may be a mixture of the negative electrode active material and a conductive assistant.

[0083] [Electrolytes] In this embodiment, the electrolytic solution 250 realizes ion conduction between the positive electrode active material and the negative electrode active material via the electrolyte contained in the electrolytic solution 250. According to this embodiment, a non-aqueous electrolytic solution is used as the electrolytic solution 250. As the non-aqueous electrolytic solution, a known organic electrolytic solution may be used. For example, when the power storage cell 112 is a lithium ion secondary battery or a lithium metal secondary battery, (i) a solvent consisting of one or more of ethylene carbonate, dimethyl carbonate, diethyl carbonate, etc., and (ii) lithium perchlorate, LiPF 6 A solution in which a lithium salt such as the above is dissolved is used as the electrolyte 250.

[0084] The non-aqueous electrolyte contains, for example, a metal salt and a non-aqueous solvent. Examples of the metal salt include sodium salts and lithium salts. Examples of the sodium salt include NaPF 6 , NaBF 4 , NaClO 4 and NaAsF 6 Inorganic sodium salts such as NaCF 3 SO 3 , NaN(CF 3 SO 2 ) 2 , NaN(C 2 F 5 SO 2 ) 2 , NaC(CF 3 SO 2 ) 3 Examples of the lithium salt include organic sodium salts such as LiPF 6 , LiBF 4 , LiClO 4 , LiAsF 6 Inorganic lithium salts such as LiCF 3SO 3 , LiN(CF 3 SO 2 ) 2 , LiN(C 2 F 5 SO 2 ) 2 , LiC(CF 3 SO 2 ) 3 Examples of the non-aqueous solvent include ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), butylene carbonate (BC), fluoroethylene carbonate (FEC), γ-butyrolactone, sulfolane, acetonitrile, 1,2-dimethoxymethane, 1,3-dimethoxypropane, diethyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, and mixtures thereof.

[0085] The concentration of the sodium salt in the non-aqueous electrolyte is not particularly limited, but may be within the range of 0.5 to 4.0 mol / L. The concentration of the sodium salt may be within the range of 0.7 mol / L to 2.0 mol / L, or within the range of 1.0 mol / L to 1.5 mol / L. The concentration of the lithium salt in the non-aqueous electrolyte is not particularly limited, but may be within the range of 0.5 to 4.0 mol / L. The concentration of the lithium salt may be within the range of 0.7 mol / L to 2.0 mol / L, or within the range of 1.0 mol / L to 1.5 mol / L.

[0086] [An example of another embodiment] In the present embodiment, the details of the storage cell 112 have been described by taking as an example a case in which the storage cell 112 is a coin-type secondary battery. However, the type, structure, and the like of the storage cell 112 are not limited to those of the present embodiment. In another embodiment, the storage cell 112 may be a cylindrical battery including a wound electrode body in which a positive electrode, a separator, and a negative electrode are wound in a spiral shape. In yet another embodiment, the storage cell 112 may be a laminated battery in which a laminated electrode body in which positive electrodes and negative electrodes are alternately stacked with a separator sandwiched therebetween is sealed with a laminate.

[0087] In this embodiment, the details of the storage cell 112 have been described by taking as an example a case in which the negative electrode 240 has the negative electrode current collector 242 and the negative electrode active material layer 244. However, the negative electrode of the storage cell 112 is not limited to this embodiment. In other embodiments, for example, when the storage cell 112 is a lithium metal secondary battery, metallic lithium can be used as the negative electrode.

[0088] In the present embodiment, an example of the storage cell 112 has been described using the electrolytic solution 250 as the electrolyte of the storage cell 112. However, the electrolyte of the storage cell 112 is not limited to the present embodiment. In other embodiments, a solid electrolyte or a gel electrolyte may be used as the electrolyte of the storage cell 112. The solid electrolyte may be Li 2 SP 2 S 5 system, Li 2 S-GeS 2 -P 2 S 5 Examples of the inorganic solid electrolyte include those based on the above-mentioned system.

[0089] As described above, the details of the aircraft 100 and the power storage cell 112 have been described using Figures 1 and 2. Next, the details of the active material for secondary batteries used as the positive electrode active material or the negative electrode active material will be described.

[0090] [I. Active material] As described above, according to this embodiment, an oligomer in which a plurality of phenazine structures are bonded is used as a positive electrode active material or a negative electrode active material (sometimes simply referred to as an active material) for a secondary battery.

[0091] In this embodiment, the active material includes at least one of compounds represented by the following general formulas (1), (2), (3), and (4) or a salt thereof. The compound or a salt thereof may be included in any of the starting material, product, and intermediate product in the discharge reaction of the battery electrode reaction. The compound or a salt thereof may be included in any of the starting material, product, and intermediate product in the charge reaction of the battery electrode reaction.

[0092] [General formula (1)] [ka] In the general formula (1), R 11 , R at the end 12 , R 13 and R 14 are each independently an oxygen atom, a group represented by -OM (sometimes referred to as an OM group), a hydrogen atom, or an organic group, and M is a hydrogen atom, or a monovalent or divalent metal atom. In the OM group, the bond between O and the metal atom may be an ionic bond.

[0093] When M is a divalent metal atom, two adjacent R 11 ~R 14 may be linked together to form a ring represented by -OMO-. In this case, the terminal R 11 is R 11 R attached to the benzene ring to which 13 and R 12 is R 12 R attached to the benzene ring to which 14 For example, when M is Mg, R 11 and the adjacent R 13 and may form a ring represented by -OMgO-.

[0094] The solid and dashed double lines represent single or double bonds. In general formula (1), the single and double bonds may be arranged so that the compound is a conjugated molecule and has a resonance structure.

[0095] In this embodiment, the square brackets in the chemical formula represent repeating units in the molecule. The solid and dashed lines passing through the square brackets represent bonds between repeating units or between a repeating unit and an end group (R 11 and R 12 ) is shown.

[0096] In general formula (1), a1 represents the number of repeating units of the phenazine structure. a1 may be an integer from 2 to 10. By setting a1 within this range, dissolution of the active material in the electrolyte during charging and discharging can be suppressed, and the cycle performance of the secondary battery can be improved. In addition, a decrease in the crystallinity of the active material and a decrease in electronic conductivity can be suppressed.

[0097] In the general formula (1), b1 and c1 may each independently be an integer from 1 to 3. When b1 and c1 are 2 or 3, R 13 and R 14 are the same or different, R 13 and R 14 At least four of R may be an oxygen atom or a group represented by -OM. 13 and R 14 The number of oxygen atoms or OM groups in R may be an even number of 4 or more. 13 and R 14 may all be oxygen atoms or OM groups.

[0098] This increases the number of electrons involved in the redox reaction. Specifically, a multi-electron reaction involving four or more electrons becomes possible in the redox reaction, increasing the theoretical capacity of the active material. Therefore, the active material can store more charge even with a small molecular weight. As a result, a storage cell with a high energy density per unit mass can be obtained.

[0099] When the active material is fully charged, the R 11 ~R 14 The bond between the oxygen atom contained in and the carbon of the benzene ring contained in the phenazine structure is a double bond. In this case, the nitrogen atom contained in the pyrazine ring of the phenazine structure is not bonded to the atom represented by M described above. For example, the nitrogen atom is not bonded to a hydrogen ion or a metal ion.

[0100] On the other hand, when the active material is fully discharged, the above R 11 ~R 14 All oxygen atoms in the OM group are present as OM groups, and the bond between the oxygen atom of the OM group and the carbon of the benzene ring in the phenazine structure is a single bond. At this time, the nitrogen atom in the pyrazine ring of the phenazine structure is bonded to the atom represented by M described above. For example, a hydrogen ion or a metal ion is bonded to the nitrogen atom.

[0101] R 11 From R 14 The organic group represented by R may be a substituted or unsubstituted hydrocarbon group. The hydrocarbon group may be a monovalent hydrocarbon group. 11 From R 14 In the organic group represented by the formula: two adjacent organic groups may be linked to each other to form a ring.

[0102] Examples of the organic group include a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted carboxy group, a substituted or unsubstituted alkoxycarbonyl group, a substituted or unsubstituted acyl group, a substituted or unsubstituted acyloxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted heteroaryloxy group, a substituted or unsubstituted ester group, a substituted or unsubstituted ether group, a substituted or unsubstituted amino group, a substituted or unsubstituted sulfonic acid group, a substituted or unsubstituted cyano group, and a substituted or unsubstituted thioether group. The organic group may be a monovalent group having an ester bond (-COO-) or a monovalent group having an ether bond (-O-). The organic group may contain boron. The organic group may contain boron as a heteroatom.

[0103] The organic group may be composed of one or more atoms selected from the group consisting of carbon, hydrogen, oxygen, nitrogen, and boron. These atoms have smaller atomic weights than, for example, sulfur. Therefore, when the organic group is composed of carbon, hydrogen, oxygen, nitrogen, and boron, the molecular weight of the compound used as the active material becomes relatively small. As a result, the mass energy density of the active material or the storage cell is improved. The organic group may be composed of one or more atoms selected from the group consisting of carbon, hydrogen, oxygen, and nitrogen.

[0104] When the number of electrons involved in the oxidation-reduction reaction in the active material is the same, the amount of charge that can be accumulated per unit mass decreases as the molecular weight of the active material increases. Therefore, when the organic group is a substituted or unsubstituted hydrocarbon group, the number of carbon atoms in the organic group is preferably 1 to 6, more preferably less than 4, and even more preferably 2 or less. The number of carbon atoms in the organic group may be 1.

[0105] Examples of the alkyl group include alkyl groups having 1 to 6 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl. The number of carbon atoms in the alkyl group is particularly preferably 1 to 3. The alkyl group may be a linear alkyl group or a branched alkyl group.

[0106] Examples of the alkoxy group include alkoxy groups having 1 to 6 carbon atoms, such as methoxy, ethoxy, n-propoxy, isopropoxy, n-butyloxy, isobutyloxy, sec-butyloxy, and tert-butyloxy. The number of carbon atoms in the alkoxy group is particularly preferably 1 to 3. The alkoxy group may be a linear alkoxy group or a branched alkoxy group.

[0107] Examples of the aryl group include a phenyl group, a naphthyl group, an anthranyl group, a phenanthryl group, a biphenyl group, and a pyridyl group. The aryl group is particularly preferably a phenyl group.

[0108] R 11 From R 14 In the OM group represented by the formula (I), M may be H, Li, Na, K, Mg, or Ca. The type of metal atom represented by M may be the same as the type of metal atom constituting the metal ion moving between the positive electrode and the negative electrode of the secondary battery. For example, when the secondary battery is a lithium ion secondary battery or a lithium metal secondary battery, M represents a hydrogen atom or a lithium atom. When the secondary battery is a sodium ion battery, M represents a hydrogen atom or a sodium atom.

[0109] As described above, when the number of electrons involved in the redox reaction in the active material is the same, the amount of charge that can be stored per unit mass decreases as the molecular weight of the active material increases. Therefore, the smaller the ratio of the molecular weight of the compound represented by general formula (1) to the number of electrons involved in the redox reaction in the compound, the higher the volumetric energy density of the compound can be. Considering the ease of synthesis and the amount of charge that can be stored per unit mass, R 11 From R 14 Among these, those other than the oxygen atom or the OM group are preferably hydrogen atoms.

[0110] The above general formula (1) may be represented, for example, by the following chemical formula (1A). [Chemical formula (1A)] [ka]

[0111] [General formula (2)] [ka] In the general formula (2), R 21 , R at the end 22 , R 23 and R 24 each independently represents an oxygen atom, a group represented by -OM, a hydrogen atom, or an organic group; M represents a hydrogen atom, or a monovalent or divalent metal atom; when M is a divalent metal atom, two adjacent R 21 ~R 24 may be linked to each other to form a ring represented by -OMO-. The ring represented by -OMO- may have the same structure as -OMO- described above for general formula (1).

[0112] L is a divalent linker containing a direct bond or an aromatic group, a double bond or a triple bond. The linker may be an organic group containing an arylene group, a heterocyclic group, an alkenylene group or an alkynylene group. The linker may be, for example, a phenylene group, an ethene-1,2-diyl group, or an acetylene-1,2-diyl group. In general formula (2), L may be the same or different for each repeat unit described in the square brackets.

[0113] The solid and dashed double lines indicate single or double bonds. The single and double bonds may be arranged such that the compounds are conjugated molecules and have resonance structures.

[0114] In the general formula (2), a2 represents the number of repeating units consisting of the phenazine structure and the linker contained in the oligomer, and may be an integer of 2 to 10.

[0115] In the general formula (2), b2 and c2 each independently represent an integer of 1 to 3. When b2 and c2 are 2 or 3, R is 2 or 3. 23 and R 24 are the same or different, R 23 and R 24 At least four of R may be an oxygen atom or a group represented by -OM. 23 and R 24 The number of oxygen atoms or OM groups in R may be an even number of 4 or more. 23 and R 24 may all be oxygen atoms or OM groups.

[0116] R 21 From R 24 Each of the above-mentioned R 11 From R 14 For example, R 21 From R 24 each independently represents an oxygen atom, a group represented by -OM, a hydrogen atom, or an organic group. 21 From R 24Each of R can be determined so that the compound represented by general formula (2) has symmetry. 21 From R 24 may be determined such that the compound represented by general formula (2) has an axis, plane or center of symmetry.

[0117] The above general formula (2) may be represented, for example, by the following chemical formula (2A). [Chemical formula (2A)] [ka]

[0118] [General formula (3)] [ka] In the general formula (3), R 31 , R at the end 32 , R 33 ~R 36 each independently represents an oxygen atom, a group represented by -OM, a hydrogen atom, or an organic group; M represents a hydrogen atom, or a monovalent or divalent metal atom; when M is a divalent metal atom, two adjacent R 31 ~R 36 may be linked to each other to form a ring represented by -OMO- (R 31 is R 31 R in the benzene ring to which 33 Can be combined with R 32 is R 32 R in the benzene ring to which 36 The ring represented by -OMO- may have the same structure as -OMO- described above for general formula (1).

[0119] L is a direct bond or a divalent linker containing an aromatic group, a double bond or a triple bond. Solid and dashed double lines indicate single or double bonds. The single and double bonds may be arranged such that the compounds are conjugated molecules and have resonance structures.

[0120] In the general formula (3), a3 represents the number of repeating units of the phenazine structure linked via the linker described in the square brackets. a3 may be an integer of 1 to 5.

[0121] In the general formula (3), b31, b32, c31, and c32 may each independently be an integer from 1 to 3. When b31, b32, c31, and c32 are 2 or 3, R 33 , R 34 , R 35 and R 36 are the same or different, R 33 and R 34 At least four of the above and R 35 and R 36 At least four of R may be an oxygen atom or a group represented by -OM. 33 and R 34 The number of oxygen atoms or OM groups in R may be an even number of 4 or more. 23 and R 24 All of R may be oxygen atoms or OM groups. 35 and R 36 The number of oxygen atoms or OM groups in R may be an even number of 4 or more. 35 and R 36 may all be oxygen atoms or OM groups.

[0122] R 31 From R 36 Each of the above-mentioned R 11 From R 14 For example, R 31 From R 36 each independently represents an oxygen atom, a group represented by -OM, a hydrogen atom, or an organic group. 31 From R 36 Each of R can be determined so that the compound represented by general formula (3) has symmetry. 31 From R 36 may be determined such that the compound represented by general formula (3) has an axis, plane or center of symmetry.

[0123] [General formula (4)] [ka] In the general formula (4), R 41 , R 43 and R 44 each independently represents an oxygen atom, a group represented by -OM, a hydrogen atom, or an organic group; M represents a hydrogen atom, or a monovalent or divalent metal atom; when M is a divalent metal atom, two adjacent R 41 , R 43 and R 44 may be linked to each other to form a ring represented by -OMO- (R 14 is R 41 R in the benzene ring to which 43 The ring represented by -OMO- may have the same structure as -OMO- described above for general formula (1).

[0124] L is a k-valent linker containing a direct bond, an aromatic group, a double bond or a triple bond. k is an integer of 2 or more. The linker may be an organic group containing an arylene group, a heterocyclic group, an alkenylene group or an alkynylene group. When k is 2, the linker may be a phenylene group, an ethene-1,2-diyl group, or an acetylene-1,2-diyl group. When k is 3 or more, the linker may be, for example, a linker containing a benzene ring, a triazine-2,4,6-triyl group, or a linker containing a phenazine structure. When k is 3 or more, if the linker is a structure containing a nitrogen atom such as a triazine or phenazine structure, steric hindrance is reduced and the active material becomes a highly planar molecule, improving crystallinity, which can further suppress dissolution of the active material in the electrolyte.

[0125] The solid and dashed double lines indicate single or double bonds. The single and double bonds may be arranged such that the compounds are conjugated molecules and have resonance structures.

[0126] In the general formula (4), a4 represents the number of repeating units of the phenazine structure described in the square brackets. a4 may be an integer of 1 to 5.

[0127] In the general formula (4), b4 and c4 may each independently be an integer from 1 to 3. When b4 and c4 are 2 or 3, R 43 and R 44 are the same or different, R 43 and R 44 At least four of R may be an oxygen atom or a group represented by -OM. 43 and R 44 The number of oxygen atoms or OM groups in R may be an even number of 4 or more. 43 and R 44 may all be oxygen atoms or OM groups.

[0128] R 41 , R 43 and R 44 Each of the above-mentioned R 11 From R 14 For example, R 41 , R 43 and R 44 each independently represents an oxygen atom, a group represented by -OM, a hydrogen atom, or an organic group. 41 , R 43 and R 44 Each of R can be determined so that the compound represented by general formula (4) has symmetry. 41 , R 43 and R 44 may be determined such that the compound represented by general formula (4) has an axis, plane or center of symmetry.

[0129] In this embodiment, the compound represented by the above general formula (4) may have symmetry. For example, the compound represented by the general formula (4) may have an axis of symmetry, a plane of symmetry, or a center of symmetry.

[0130] The above general formula (1) may be represented by the following general formula (5). [General formula (5)] [ka] In the general formula (5), R 101 , R at the end 102 , R 103 ~R 108 each independently represents an oxygen atom, a group represented by -OM, a hydrogen atom, or an organic group; M represents a hydrogen atom, or a monovalent or divalent metal atom; when M is a divalent metal atom, two adjacent R 101 ~R 108が They may be linked together to form a ring represented by -OMO-. A solid line and a double line represented by a dashed line indicate a single bond or a double bond. R 103 ~R 108 At least four of R may be an oxygen atom or a group represented by -OM. 103 ~R 108 The number of oxygen atoms or OM groups in R may be an even number of 4 or more. 103 ~R 108 All of R may be oxygen atoms or OM groups. 101 ~R 108 Each of the above-mentioned R 11 From R 14 It may have a similar configuration.

[0131] In the general formula (5), a1 represents the number of repeating units of the phenazine structure, and may be an integer of 2 to 10.

[0132] In this embodiment, the compound represented by the above general formula (5) may have symmetry. For example, the compound represented by the general formula (5) may have an axis of symmetry, a plane of symmetry, or a center of symmetry.

[0133] The above general formula (2) may be represented by the following general formula (6). [General formula (6)] [ka] In the general formula (6), R 201 , R at the end 202 , R 203 ~R 208each independently represents an oxygen atom, a group represented by -OM, a hydrogen atom, or an organic group; M represents a hydrogen atom, or a monovalent or divalent metal atom; when M is a divalent metal atom, two adjacent R 201 ~R 208 may be linked together to form a ring represented by -OMO-. L is a divalent linker containing a direct bond, an aromatic group, a double bond or a triple bond, and may have the same structure as the linker of the above general formula (1). The double line shown by a solid line and a dashed line indicates a single bond or a double bond. R 203 ~R 208 At least four of R may be an oxygen atom or a group represented by -OM. 201 ~R 208 Each of the above-mentioned R 11 From R 14 It may have a similar configuration.

[0134] In the general formula (6), a2 represents the number of repeating units consisting of a phenazine structure and a linker contained in the oligomer. a2 may be an integer from 2 to 10. When a2 is in this range, dissolution of the active material in the electrolyte during charging and discharging can be suppressed, and the cycle performance of the secondary battery can be improved. In addition, a decrease in the crystallinity of the active material and a decrease in electronic conductivity can be suppressed.

[0135] In this embodiment, the compound represented by the above general formula (6) may have symmetry. For example, the compound represented by the general formula (6) may have an axis of symmetry, a plane of symmetry, or a center of symmetry.

[0136] The above general formula (3) may be represented by the following general formula (7). [General formula (7)] [ka] In the general formula (7), R 301 , R at the end 302 , R 303 ~R 314each independently represents an oxygen atom, a group represented by -OM, a hydrogen atom, or an organic group; M represents a hydrogen atom, or a monovalent or divalent metal atom; when M is a divalent metal atom, two adjacent R 301 ~R 314 may be linked together to form a ring represented by -OMO-. L is a divalent linker containing a direct bond, an aromatic group, a double bond or a triple bond, and may have the same structure as the linker of the above general formula (1). The double line shown by a solid line and a dashed line indicates a single bond or a double bond. R 303 ~R 308 At least four of the above and R 309 ~R 314 At least four of R may be an oxygen atom or a group represented by -OM. 301 ~R 314 Each of the above-mentioned R 11 From R 14 It may have a similar configuration.

[0137] In the general formula (7), a3 represents the number of repeating units of the phenazine structure bonded via a linker. a3 may be an integer from 1 to 5. When a3 is within this range, dissolution of the active material in the electrolyte during charging and discharging can be suppressed, and the cycle performance of the secondary battery can be improved. In addition, a decrease in the crystallinity of the active material and a decrease in electronic conductivity can be suppressed.

[0138] In this embodiment, the compound represented by the above general formula (7) may have symmetry. For example, the compound represented by the general formula (7) may have an axis of symmetry, a plane of symmetry, or a center of symmetry.

[0139] The above general formula (4) may be represented by the following general formula (8). [General formula (8)] [ka] In the general formula (8), R 401 , R 403 ~R 408each independently represents an oxygen atom, a group represented by -OM, a hydrogen atom, or an organic group; M represents a hydrogen atom, or a monovalent or divalent metal atom; when M is a divalent metal atom, two adjacent R 401 and R 403 ~R 408 may be linked together to form a ring represented by -OMO-. L is a k-valent linker containing a direct bond, an aromatic group, a double bond or a triple bond, and may have the same structure as the linker of the above general formula (4). k is an integer of 2 or more. A double line represented by a solid line and a dashed line indicates a single bond or a double bond. R 403 ~R 408 At least four of may be an oxygen atom or a group represented by -OM.

[0140] In the general formula (8), a4 represents the number of repeating units of the phenazine structure. a4 may be an integer from 1 to 5. When a4 is in this range, dissolution of the active material into the electrolyte during charging and discharging can be suppressed, and the cycle performance of the secondary battery can be improved. In addition, a decrease in the crystallinity of the active material and a decrease in electronic conductivity can be suppressed.

[0141] In the above general formulas (1) to (8), L is a divalent or higher linker containing a direct bond, an aromatic group, a double bond, or a triple bond. The linker may be an organic group containing an arylene group, a heterocyclic group, an alkenylene group, or an alkynylene group. The arylene group may be, for example, a phenylene group. The heterocyclic group may include, for example, a phenazine structure.

[0142] An example in which L in general formula (4) contains a phenazine structure is shown in general formula (9). [General formula (9)] [ka] In the general formula (9), R 501 , R at the end 502 , R 503 ~R 508each independently represents an oxygen atom, a group represented by -OM, a hydrogen atom, or an organic group; M represents a hydrogen atom, or a monovalent or divalent metal atom; when M is a divalent metal atom, two adjacent R 501 ~R 508 may be linked together to form a ring represented by -OMO-. A double line represented by a solid line and a dashed line indicates a single bond or a double bond. In general formula (9), the planarity of an active material containing a plurality of phenazine structures is improved by including a phenazine structure in the linker, and thus the crystallinity of the active material is improved, and dissolution in an electrolyte can be further suppressed.

[0143] In the general formula (9), a51 and a53 are each independently an integer of 1 to 5, and b51, b52, b53, c51, c52, and c53 are each independently an integer of 1 to 3. When b51, b53, c51, and c53 are each independently an integer of 2 or 3, R 503 , R 504 , R 507 and R 508 are the same or different, R 503 and R 504 At least four of the above and R 507 and R 508 At least four of are oxygen atoms or groups represented by -OM. Each of n and m is an integer of 1 to 3, and the sum of n and b52, and the sum of m and c52 are each 4 or less.

[0144] R 501 From R 508 Each of the above-mentioned R 11 From R 14 For example, R 501 From R 508 each independently represents an oxygen atom, a group represented by -OM, a hydrogen atom, or an organic group. 501 From R 508 Each of R can be determined so that the compound represented by general formula (9) has symmetry. 501 From R 508may be determined such that the compound represented by general formula (9) has an axis, plane or center of symmetry.

[0145] [Specific examples of compounds used as active materials] In one embodiment, specific examples of the active material include the following compounds.

[0146] The following compounds (1) to (5) correspond to a fully charged state of the active material. The following compounds may be examples of fully oxidized forms of the compounds represented by general formulas (1) to (9). Note that the following compounds are conjugated molecules and have a resonance structure. The compounds represented by general formulas (1) to (9) above are not limited to these. Other specific examples include fully reduced or partially reduced forms of the following compounds.

[0147] [An example of a fully oxidized product] [Compound (1)] [ka] [Compound (2)] [ka] [Compound (3)] [ka] [Compound (4)] [ka] [Compound (5)] [ka]

[0148] The following compounds (6) to (10) correspond to a fully discharged state of the active material. The following compounds (6) to (10) may be examples of fully reduced forms of the compounds represented by general formulas (1) to (9). The following compounds may be fully reduced forms of the above compounds exemplified as compounds corresponding to a fully charged state of the active material. It should be noted that the following compounds are conjugated molecules and have resonance structures.

[0149] [An example of a fully reduced form] [Compound (6)] [ka] [Compound (7)] [ka] [Compound (8)] [ka] [Compound (9)] [ka] [Compound (10)] [ka]

[0150] [Method of manufacturing active material] The above active materials are either known compounds or can be synthesized employing known reactions.

[0151] [Synthesis Example 1] The compound (1), a dimeric oligomer of phenazine tetraone, and the compound (2), a trimer oligomer of phenazine tetraone, can be synthesized according to the following reaction formula (1).

[0152] [Reaction scheme (1)] [ka]

[0153] 87.0 mg (0.20 mmol) of tetraethoxyphenazine bromide, 51.4 mg (0.10 mmol) of tetraethoxyphenazine dibromide, 63.5 mg (0.25 mmol) of bis(pinacolato)diboron, 12.5 mol% of palladium(0) catalyst, and cesium salt were added to a 100 mL vial. 5 mL of xylene was added to the mixture, argon gas was injected, and the vial was sealed. After stirring at 135°C for 24 hours, the solvent was distilled off from the reaction solution to obtain a yellow solid, which was dissolved in dichloromethane and roughly purified using a silica gel column to obtain a mixture of dimer oligomers and trimer oligomers in which tetraethoxyphenazine was directly bonded. The dimer and trimer of tetraethoxyphenazine were separated from the oligomer mixture by gel permeation chromatography (GPC) and separated into 50 mL vials. Mass spectrometry: 711 ([M(C 40 H 46 N 4 O 8 )+H] + ), 1065([M(C 60 H 68 N 6 O 12 )+H] + ).

[0154] Next, the separated tetraethoxyphenazine dimer was added to a 25 wt% 1,2-dichloroethane solution in which 71.1 mg (0.100 mmol) and 500 mg of boron tribromide (2.0 mmol) were dissolved, and the mixture was heated and stirred at 80°C for 18 hours. After the reaction, pure water was added to the solution to precipitate a purple-brown solid. The precipitated solid was filtered and washed with water. The obtained solid was suspended in 10 mL of acetonitrile in a 50 mL vial, and 2 mL of an aqueous solution containing 658 mg (1.20 mmol) of CAN was added dropwise, and the mixture was heated and stirred at 40°C for 1 hour. The resulting brown precipitate was filtered and washed with water and methanol. The brown precipitate was then air-dried to obtain a brown powder of the phenazine tetraone dimer. The phenazine tetraone trimer was also synthesized by the same method.

[0155] [Synthesis Example 2] Moreover, the p-phenylenephenazine dimer oligomer in the above compound (4) can be synthesized according to the following reaction formula (2).

[0156] [Reaction scheme (2)] [ka]

[0157] 218 mg (0.5 mmol) of tetraethoxyphenazine bromide, 80.7 mg (0.2 mmol) of 1,4-bis(trimethylstannyl)benzene, and 10 mol% of palladium(0) catalyst were added to a 100 mL vial. This was dissolved in 20 mL of 1,4-dioxane, and argon gas was injected into the vial, which was then sealed. After heating and stirring at 85°C for 72 hours, the mixture was cooled to room temperature, and the resulting yellow solid was filtered. The filtered solid was washed with ethyl acetate and purified by column purification using silica gel, obtaining the phenylene dimer of tetraethoxyphenazine as a yellow solid. Mass spectrometry: 787([M(C 46 H 50 N 4 O 8 )+H] + ).

[0158] Of the yellow solid obtained above, 78.7 mg (0.10 mmol) was added to a 100 mL vial and suspended in 10 mL of acetonitrile. The suspension was stirred at room temperature, and 2 mL of an aqueous solution containing 658 mg (1.2 mmol) of ammonium hexanitratocerate (IV) (hereinafter referred to as CAN) was added dropwise, and the mixture was stirred at room temperature for 2 hours. The yellowish brown precipitate formed in the solution was filtered and washed with water and methanol. The phenylene dimer of phenazine tetrone was obtained as a brown solid by air drying. EXAMPLES

[0159] An R2032 coin type battery was produced using the phenazines synthesized in the above Synthesis Examples 1 and 2 as the positive electrode active material. The R2032 coin type battery was produced by the following procedure.

[0160] First, phenazines as a positive electrode active material, acetylene black (manufactured by Denka Co., Ltd.) as a conductive additive, and PTFE (manufactured by Daikin Industries, Ltd.) as a binder were mixed in a ratio of positive electrode active material:conductive additive:binder=4:5:1 (mass ratio) to prepare a positive electrode active material sheet with a diameter of about 10 mm and a thickness of about 100 μm. The positive electrode active material sheet was pressed onto a stainless steel mesh (manufactured by Hosen Co., Ltd., SUS316L) with a diameter of 14 mm and a thickness of 100 μm to prepare a positive electrode.

[0161] Next, a circular member with a diameter of 13 mm was cut out from a 0.5 mm thick lithium metal foil (manufactured by Honjo Metals Co., Ltd., purity 99.8% or more). The member cut out from the lithium foil was pressed onto a stainless steel plate with a diameter of 15.5 mm and a thickness of 0.5 mm (manufactured by Hosen Co., Ltd.) to prepare a negative electrode.

[0162] In addition, a glass filter (manufactured by Advantech Co., Ltd.) with a diameter of 16 mm and a thickness of 0.4 mm was prepared as a separator. 6 A non-aqueous electrolyte (Kishida Chemical Co., Ltd.) containing a mixture of ethylene carbonate and diethyl carbonate was prepared. The above positive electrode, separator, negative electrode, and electrolyte were placed inside a battery case conforming to the R2032 coin battery standard to prepare a test coin battery.

[0163] The test coin-type battery was tested at 1.2-3.5 V (vs. Li) at a current density of 20 mA / g in an atmosphere of 30°C. C.E. ) or 1.0-4.2V (vs. Li C.E. ) charge / discharge tests were performed in the voltage range.

[0164] FIG. 3 shows the transition of the capacity retention rate in the charge-discharge test of the secondary battery of this embodiment. FIG. 3 shows the transition of the capacity retention rate of the secondary battery produced using the dimer oligomer of phenazine tetraone of compound (1), the trimer oligomer of phenazine tetraone of compound (2), and the monomer of phenazine tetraone as a comparative example as a positive electrode active material, with the cycle. The discharge capacity at the first cycle was 363 mAh / g when the dimer oligomer of phenazine tetraone was used, and 442 mAh / g when the trimer oligomer of phenazine tetraone was used, showing a high capacity. The capacity retention rate of the secondary battery using the dimer oligomer and trimer oligomer at the second cycle of the charge-discharge test was higher than that of the secondary battery using the monomer. The capacity after 10 cycles was 159 mAh / g in the case of the dimer oligomer and 203 mAh / g in the case of the trimer oligomer, showing a higher discharge capacity than the monomer. The capacity retention rate after 10 cycles was 44% for the dimer oligomer and 46% for the trimer oligomer, which was higher than that of the monomer. Therefore, a secondary battery containing an oligomer in which multiple phenazine structures are bonded as an active material can maintain a higher capacity retention rate than a monomeric phenazine. By using the active material for secondary batteries of this embodiment as an active material, a secondary battery can be provided that has a large amount of charge that can be stored per unit mass and has improved cycle performance.

[0165] FIG. 4 shows the transition of the capacity retention rate in the charge-discharge test of the secondary battery of this embodiment. FIG. 4 shows the transition of the capacity retention rate with cycles of the secondary battery manufactured using the p-phenylenephenazine dimer oligomer of compound (4) and the phenazine tetraone monomer as a comparative example as the active material. In the secondary battery using the p-phenylenephenazine dimer oligomer, the discharge capacity at the first cycle was 439 mAh / g, which was a high discharge capacity. In addition, in the secondary battery using the p-phenylenephenazine dimer oligomer, the capacity decrease with cycles was smaller than that in the case of using the phenazine tetraone monomer, and in the second cycle, the capacity retention rate was higher than that in the case of using the phenazine tetraone monomer. In the case of using the p-phenylenephenazine dimer oligomer, the discharge capacity after 10 cycles was 126 mAh / g, and the capacity retention rate was 29%. On the other hand, in the case of the phenazine tetraone monomer, the discharge capacity after 10 cycles was 112 mAh / g, and the capacity retention rate was 22%. Therefore, a secondary battery containing an oligomer in which a plurality of phenazine structures are linked via a linker as an active material can maintain a higher capacity retention rate than that of monomeric phenazines. By using the active material for secondary batteries of this embodiment as an active material, a secondary battery can be provided that has a large amount of charge that can be stored per unit mass and has improved cycle performance.

[0166] Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It is clear to those skilled in the art that various modifications and improvements can be made to the above embodiments. It is clear from the description of the claims that such modifications and improvements can also be included in the technical scope of the present invention.

[0167] It should be noted that the order of execution of each process, such as operations, procedures, steps, and stages, in the devices, systems, programs, and methods shown in the claims, specifications, and drawings is not specifically stated as "before," "prior to," etc., and may be realized in any order unless the output of a previous process is used in a later process. Even if the operational flow in the claims, specifications, and drawings is explained using "first," "next," etc. for convenience, it does not mean that it is essential to perform the process in this order. [Explanation of symbols]

[0168] 100 aircraft, 110 storage battery, 112 storage cell, 120 power control circuit, 130 motor, 140 propeller, 150 sensor, 160 control device, 212 positive electrode case, 214 negative electrode case, 216 sealant, 218 metal spring, 220 positive electrode, 222 positive electrode current collector, 224 positive electrode active material layer, 230 separator, 240 negative electrode, 242 negative electrode current collector, 244 negative electrode active material layer, 250 electrolyte

Claims

1. A secondary battery active material used as an active material for a secondary battery, The active material comprises at least one compound represented by the following general formulas (5) to (8) or a salt thereof. Active material for secondary batteries. [General formula (5)] 【Chemistry 42】 In general formula (5), the R of the terminal part １０１ , the R at the end １０２ , R １０３ ~R １０８ Each of these independently represents an oxygen atom, a group represented by -OM, a hydrogen atom, or an organic group, and M represents a hydrogen atom or a monovalent or divalent metal atom. If M is a divalent metal atom, then two adjacent R １０１ ~R １０８が They connect to each other, forming a ring represented by -OMO-, Double lines, shown as solid and dashed lines, indicate single or double bonds. R １０３ ~R １０８ At least four of these are oxygen atoms or groups represented by -OM, a1 is an integer between 2 and 10, [General formula (6)] 【Chemistry 43】 In the general formula (6), R at the terminal ２０１ , R at the terminal ２０２ , R ２０３ to R ２０８ each independently represents an oxygen atom, a group represented by -OM, a hydrogen atom or an organic group, M represents a hydrogen atom, or a monovalent or divalent metal atom, and when M is a divalent metal atom, two adjacent R's ２０１ to R ２０８ are connected to each other to form a ring represented by -OMO-, L is a divalent linker containing a direct bond, an aromatic group, a double bond, or a triple bond. Double lines, shown as solid and dashed lines, indicate single or double bonds. R ２０３ ~R ２０８ At least four of these are oxygen atoms or groups represented by -OM, a2 is an integer between 2 and 10. [General formula (7)] 【Chemistry 44】 In general formula (7), the R at the end ３０１ , the R at the end ３０２ , R ３０３ ~R ３１４ Each of these independently represents an oxygen atom, a group represented by -OM, a hydrogen atom, or an organic group, and M represents a hydrogen atom or a monovalent or divalent metal atom. If M is a divalent metal atom, then two adjacent R ３０１ ~R ３１４ These are connected to each other, forming a ring represented by -OMO-, L is a divalent linker containing a direct bond, an aromatic group, a double bond, or a triple bond. Double lines, shown as solid and dashed lines, indicate single or double bonds. R ３０３ ~R ３０８ At least four of the following and R ３０９ ~R ３１４ At least four of these are oxygen atoms or groups represented by -OM, a3 is an integer from 1 to 5, [General formula (8)] 【Chemistry 45】 In general formula (8), the R at the end ４０１ , R ４０３ ~R ４０８ Each of these independently represents an oxygen atom, a group represented by -OM, a hydrogen atom, or an organic group, and M represents a hydrogen atom or a monovalent or divalent metal atom. If M is a divalent metal atom, then two adjacent R ４０１ and R ４０３ ~R ４０８ These are connected to each other, forming a ring represented by -OMO-, L is a k-valent linker containing a direct bond, an aromatic group, a double bond, or a triple bond. Double lines, shown as solid and dashed lines, indicate single or double bonds. R ４０３ ~R ４０８ At least four of these are oxygen atoms or groups represented by -OM, a4 is an integer from 1 to 5, and k is an integer greater than or equal to 2.

2. A secondary battery active material used as an active material for a secondary battery, The active material includes a compound represented by the following general formula (9) or a salt thereof. Active material for secondary batteries. [General formula (9)] 【Chemistry 46】 In general formula (9), the R at the end ５０１ , the R at the end ５０２ , R ５０３ ~R ５０８ Each of these independently represents an oxygen atom, a group represented by -OM, a hydrogen atom, or an organic group, and M represents a hydrogen atom or a monovalent or divalent metal atom. If M is a divalent metal atom, then two adjacent R ５０１ ~R ５０８ These are connected to each other, forming a ring represented by -OMO-, Double lines, shown as solid and dashed lines, indicate single or double bonds. a51 and a53 are each independent integers from 1 to 5, and b51, b52, b53, c51, c52, and c53 are each independent integers from 1 to 3. If b51, b53, c51 and c53 are 2 or 3, then R is 2 or 3. ５０３ , R ５０４ , R ５０７ and R ５０８ Each is either identical or different from the others, R ５０３ and R ５０４ At least four of the following and R ５０７ and R ５０８ At least four of these are oxygen atoms or groups represented by -OM, n and m are integers from 1 to 3, The sum of n and b52, and the sum of m and c52, are both less than or equal to 4.

3. The aforementioned compound has symmetry, The active material for a secondary battery according to claim 1 or 2.

4. The aforementioned L is an organic group that is directly bonded or contains an arylene group, a heterocyclic group, an alkenylene group, or an alkynylene group. The active material for a secondary battery according to claim 1.

5. The aforementioned compound, 【Chemistry 47】 【Chemistry 48】 【Chemistry 49】 [Transformation 50] 【Chemistry 51】 It is at least one of the above, or it is its complete or partial reduced form. The active material for a secondary battery according to claim 1 or 2.

6. M is H, Li, Na, K, Mg, or Ca. The active material for a secondary battery according to claim 1 or 2.

7. The active material for secondary batteries according to claim 1 or 2 is included. Electrodes for secondary batteries.

8. A positive electrode active material layer containing positive electrode active material, A negative electrode active material layer containing a negative electrode active material, Electrolytes, It has, The positive electrode active material or the negative electrode active material includes the secondary battery active material described in claim 1 or 2. Secondary battery.

9. The positive electrode active material includes the active material for secondary batteries. The secondary battery according to claim 8.

10. The aforementioned secondary battery is a non-aqueous secondary battery. The secondary battery according to claim 8.

11. The secondary battery according to claim 8, A propulsion force generating device that generates propulsion force using electrical energy stored in the secondary battery, An aircraft equipped with [the following features].

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