Secondary battery

Abstract

A secondary battery comprising: a negative electrode 103 that contains triquinoxalinylene containing metal ions; a positive electrode 101 that contains a material capable of intercalation and deintercalation or adsorption and desorption of the metal ions; and an electrolyte 102 that is disposed between the positive electrode 101 and the negative electrode 103 and contains the metal ions.

Description

secondary battery

[0001] This disclosure relates to secondary batteries.

[0002] Conventionally, rechargeable metal anode secondary batteries containing metallic lithium, metallic magnesium, metallic sodium, etc. as a negative electrode have been developed for use in small devices, sensors, mobile devices, etc. (Patent Documents 1-3).

[0003] Japanese Patent Publication No. 2016-51614, Japanese Patent Publication No. 2016-103463, Japanese Patent Publication No. 2014-82030

[0004] The aforementioned secondary batteries use metallic lithium (Patent Document 1) or metallic sodium (Patent Document 2), which have water-reactive properties and high reactivity, as the negative electrode in a metallic state, raising concerns about the safety of the battery. Furthermore, even secondary batteries that use metallic magnesium, which has lower reactivity than metallic lithium and metallic sodium, as the negative electrode (Patent Document 3) are corrosive, making the long-term stability of the secondary battery a challenge.

[0005] This disclosure is made in view of the above circumstances and aims to provide a secondary battery that does not use a metal anode.

[0006] A secondary battery according to one aspect of the present disclosure comprises a negative electrode containing triquinoxalinylene containing metal ions, a positive electrode containing a material capable of inserting and deinserting or adsorbing and desorbing the metal ions, and an electrolyte containing the metal ions disposed between the positive electrode and the negative electrode.

[0007] According to this disclosure, it is possible to provide a secondary battery that does not use a metal anode.

[0008] Figure 1 is a schematic cross-sectional view showing the structure of the secondary battery of this embodiment. Figure 2 is a schematic cross-sectional view showing the structure of the electrochemical cell used to fabricate the negative electrode. Figure 3 is a diagram showing the discharge curve after precharging with an aqueous MgCl2 solution. Figure 4 is a diagram showing the discharge curves of Example 3 at the first charge, 10 cycles, and 30 cycles. Figure 5 is a diagram showing the battery performance of Examples 1 to 7. Figure 6 is a diagram showing the battery performance of Examples 8 to 17. Figure 7 is a diagram showing the battery performance of Comparative Examples 1 to 4. Figure 8 is a diagram showing the battery performance of Comparative Examples 5 to 11.

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0010] [Configuration of Secondary Battery] FIG. 1 is a schematic cross-sectional view showing an example of the structure (configuration) of a secondary battery in an embodiment of the present disclosure. The secondary battery of this embodiment includes a negative electrode 103 containing triquinoxalinylene containing metal ions, a positive electrode 101 containing a material capable of inserting and desorbing or adsorbing and desorbing the metal ions, and an electrolyte 102 containing the metal ions disposed between the positive electrode 101 and the negative electrode 103.

[0011] The metal M constituting the metal ions may include any one metal selected from the group consisting of Li, Na, Mg, Ca, Zn, Al, and Y. The electrolyte 102 may be an aqueous electrolyte solution. Also, the electrolyte 102 may be a non-aqueous electrolyte solution.

[0012] The illustrated secondary battery is manufactured using an electrochemical cell 100 (electrochemical beaker cell). The negative electrode 103 includes a negative electrode active material 1031 and a conductive material (or current collector) 104. The negative electrode 103 is fixed to a titanium rod 105 and disposed in the electrochemical cell 100. The positive electrode 101 includes a positive electrode active material 1011 and a conductive material (or current collector) 104. The positive electrode 101 is fixed to a titanium rod 105 and disposed in the electrochemical cell 100.

[0013] Triquinoxalinylene is an organic compound having an -N= group which is an active site containing nitrogen. The chemical formula of triquinoxalinylene (hereinafter referred to as "TQ") is shown below.

[0014]

[0015] During discharge, metal M ions are desorbed and detached from the negative electrode M-TQ containing TQ containing metal M ions, move in the electrolyte solution containing metal M ions, and are inserted and adsorbed into the positive electrode X, thereby proceeding with the discharge reaction.

[0016] Negative electrode: M-TQ → TQ + M n+ + ne - Positive electrode: X + M n+ + ne- → When charging M-X, the reaction proceeds in the reverse direction. That is, metal M ions are inserted and adsorbed onto the negative electrode TQ again, and metal M ions are desorbed and detached from the positive electrode X again.

[0017] Negative electrode: TQ + M n+ + ne - → M-TQ Positive electrode: M-X → X + M n+ + ne - Thus, in this embodiment, a secondary battery having excellent charge and discharge characteristics can be fabricated without using a metal negative electrode.

[0018] Each of the above components of the secondary battery according to this embodiment will be described below.

[0019] (1) Negative electrode The negative electrode 103 of this embodiment contains a negative electrode active material. The negative electrode 103 may contain a conductive assistant or a current collector as needed in addition to the negative electrode active material. As the current collector, a current collector containing at least one selected from the group consisting of copper and titanium, or a non-woven fabric-like current collector containing carbon can be used. Also, the negative electrode 103 may contain a binder.

[0020] (1-1) Negative electrode active material For the negative electrode active material of this embodiment, TQ containing metal M ions is used. TQ is an organic compound having a -N= group as described above. Commercially available reagents can be used for TQ.

[0021] (1-2) Preparation of negative electrode using conductive assistant In this embodiment, the negative electrode 103 may contain a conductive assistant. For the conductive assistant, for example, carbon can be used. Examples of the conductive assistant include carbon blacks such as ketjen black and acetylene black, activated carbons, graphites, carbon fibers, and the like.

[0022] In order to sufficiently secure a conductive path in the negative electrode 103, carbon with small particles is suitable. Specifically, the particle diameter of the carbon is preferably 1 μm or less. These carbons can be obtained, for example, as commercial products or by known synthesis.

[0023] The negative electrode 103 may contain a binder. Examples of binders include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), styrene-butadiene rubber, ethylene propylene diene rubber, and natural rubber.

[0024] The negative electrode 103 can be prepared by mixing the TQ powder, which is the negative electrode active material, the conductive additive, and the binder, and then joining this mixture to a conductive material. Alternatively, the negative electrode 103 may be prepared by joining this mixture to a current collector, which will be described later.

[0025] (1-3) Preparation of a negative electrode using a current collector The negative electrode 103 may include a current collector. The negative electrode active material may be formed as a current collector containing at least one selected from the group consisting of copper and titanium, or as a nonwoven fabric-like current collector containing carbon. These current collectors are available, for example, as commercially available products.

[0026] To form a simple and high-quality negative electrode 103, TQ powder, carbon powder, and binder powder are crushed and mixed, this mixture is rolled in a roll press to form a sheet, and the negative electrode 103 is manufactured by pressing the sheet mixture onto a current collector.

[0027] Alternatively, the negative electrode 103 can be manufactured by coating or impregnating a current collector with a slurry containing dispersed negative electrode active material and drying it. Here, by applying cold pressing or hot pressing to the dried negative electrode 103, the strength of the negative electrode 103 as an electrode can be increased, resulting in a more stable negative electrode 103.

[0028] (1-4) Method for synthesizing the negative electrode active material M-TQ. TQ is commercially available as a reagent in a state that does not contain metal M ions. In this embodiment, M-TQ containing metal M ions is prepared by an electrochemical pre-charge method.

[0029] Figure 2 shows an example of an electrochemical cell used in the pre-charge method. Here, we will explain using the case where the metal M constituting the metal M ion is Mg as an example.

[0030] An aqueous solution of 1 mol / l magnesium chloride 240 (MgCl ２ aqueous solution) is injected into a commercially available electrochemical cell 200 (electrochemical beaker cell). An operating electrode 210, a counter electrode 220, and a reference electrode 230 are arranged in the electrochemical cell 200 filled with the aqueous solution of magnesium chloride 240, and a negative electrode Mg-TQ containing metal ions of Mg is produced by flowing a constant reduction current to a predetermined potential.

[0031] For the operating electrode 210, an electrode prepared by joining a mixture 211 in which TQ, a conductive auxiliary agent (for example, carbon black), and a binder (for example, a PTFE binder) are mixed to a conductive material 212 (for example, a titanium mesh) was used. This electrode is joined to a titanium rod 213 and arranged in the electrochemical cell 200.

[0032] For the counter electrode 220, a platinum plate (Pt plate) was used. For the reference electrode 230, an electrode in which an ionic liquid 232 (for example, a 3 mol / l KCL aqueous solution) in which a salt of a predetermined concentration was dissolved in a commercially available glass tube 231 and a commercially available Ag wire (Ag / AgCl electrode) 233 was immersed therein was used. A porous glass 234 is attached to the tip of the glass tube 231.

[0033] In the case of the metal M (M = Li, Na, Ca, Zn, Al, Y) constituting the metal M ions, a negative electrode M-TQ can be similarly prepared by using an electrolytic solution containing M.

[0034] (2) Positive electrode The positive electrode 101 of the present embodiment contains a material capable of inserting and desorbing or adsorbing and desorbing metal M ions. The positive electrode 101 contains at least a positive electrode active material, and may contain a conductive auxiliary agent or a current collector described later as necessary. Further, the positive electrode 101 may contain a binder. As the current collector, a current collector containing at least one selected from the group consisting of aluminum, copper, iron, and titanium, or a non-woven fabric current collector containing carbon can be used. The positive electrode 101 can be produced by the same method as the negative electrode 103 described above.

[0035] (2-1) Positive electrode active material As the positive electrode active material of this embodiment, an organic compound containing at least an imine (-N=) group or a carbonyl (C=O) group in its structure can be used.

[0036] Alternatively, a metal oxide can be used as the positive electrode active material. For example, it may be a metal oxide containing at least one selected from the group consisting of Mn, Ni, Co, Al, Fe, and Ti.

[0037] (3) Aqueous electrolyte The electrolyte 102 contains metal M ions, which are placed between the positive electrode 101 and the negative electrode 103.

[0038] As the electrolyte 102, an aqueous electrolyte solution may be used, in which a salt containing anion X is dissolved in water, with one metal selected from Li, Na, Mg, Ca, Zn, Al, and Y as the metal M constituting the metal M ion. Examples of the anion X include Cl, Br, I, NO3, SO4, PO4, H2PO4, HPO4, HCO3, CO3, and OH.

[0039] (4) Non-aqueous electrolyte A non-aqueous electrolyte may be used as the electrolyte 102. The non-aqueous electrolyte is a solution containing the electrolyte 102 that allows for the movement of metal ions. The non-aqueous electrolyte uses an organic solvent as the main solvent.

[0040] For non-aqueous electrolytes, an electrolyte can be used that is obtained by dissolving a salt containing metal M in at least one organic solvent selected from the group consisting of, for example, carbonate ester solvents such as dimethyl carbonate (DMC), methyl ethyl carbonate (MEC), methyl carbonate (MPC), methyl isopropyl carbonate (MIPC), methyl butyl carbonate (MBC), diethyl carbonate (DEC), ethyl propyl carbonate (EPC), ethyl isopropyl carbonate (EIPC), ethyl butyl carbonate (EBC), dipropyl carbonate (DPC), diisopropyl carbonate (DIPC), dibutyl carbonate (DBC), ethylene carbonate (EC), propylene carbonate (PC), and 1,2-butylene carbonate (1,2-BC); ether solvents such as 1,2-dimethoxyethane (DME) and tetraethylene glycol dimethyl ether (TEGDME); lactone solvents such as γ-butyrotactone (GBL); or sulfoxide solvents such as dimethyl sulfoxide (DMSO).

[0041] The salts containing the aforementioned anion X are each Mg-X ２ , Li-X, Na-X, Ca-X ２ Zn-X2, Y-X ３ And it is represented as Al-X3, where X is, for example, Cl, Br, I, BF ４ , PF ６ CF ３ SO ３ , ClO ４ CF ３ CO ２ AsF ６ SbF ６ AlCl ４ , N (CF ３ SO ２ ) ２ , N (CF ３ CF ２ SO ２ ) ２ , PF ３ (C ２ F ５ ) ３ , N (FSO ２ ) ２ , N (FSO ２ ) (CF ３ SO ２ ), N (CF ３ CF ２ SO２ ) ２ , N(C ２ F ４ S ２ O ４ ), N (C ３ F ６ S ２ O ４ ), N (CN) ２ , N (CF ３ SO ２ ) (CF ３ CO) can be cited.

[0042] (4) Other elements In addition to the above-mentioned components, the secondary battery of this embodiment may include structural members such as separators and battery cases, and other elements required for a secondary battery. Conventional known components can be used for these.

[0043] (5) Method for manufacturing a secondary battery As described above, the secondary battery of this embodiment includes at least a positive electrode 101, a negative electrode 103, and an electrolyte 102 (electrolyte solution), and the electrolyte 102 is arranged between the positive electrode 101 and the negative electrode 103 so as to be in contact with the positive electrode 101 and the negative electrode 103.

[0044] A secondary battery with this configuration can be prepared in the same way as a conventional secondary battery. As an embodiment of the secondary battery manufacturing method, for example, as illustrated in Figure 1, a secondary battery can be manufactured using a commercially available glass electrochemical cell 100. Coin-type secondary batteries, laminate-type batteries, cylindrical batteries, etc., can also be manufactured.

[0045] [Examples] Examples of the secondary battery according to this embodiment will be described in detail below. However, this disclosure is not limited to the examples shown below, and can be modified as appropriate without changing the gist of the invention.

[0046] <Examples 1-7> In these examples, secondary batteries were fabricated using an electrochemical cell (see Figure 1). M-TQ prepared by precharging was used as the negative electrode, 2,5-dimethoxy-1,4-benzoquinone (hereinafter referred to as "DMBQ") was used as the positive electrode, and an aqueous solution (water-based electrolyte) containing metal chlorides (LiCl, NaCl, MgCl2, CaCl2, ZnCl2, AlCl3, YCl3) was used as the electrolyte to fabricate the secondary batteries.

[0047] (Preparation of the negative electrode) Commercially available TQ powder, Ketjenbrak powder (EC600JD, Lion Specialty Chemicals Co., Ltd.), and polytetrafluoroethylene (PTFE) powder were thoroughly ground and mixed using a grinder in a weight ratio of 40:40:20. This mixture was roll-formed to create a sheet electrode (thickness: 0.5 mm). The sheet electrode and the titanium mesh current collector were each cut into circles with a diameter of 16 mm. The circular sheet electrode was pressed and crimped onto the circular titanium mesh to obtain an unprecharged TQ negative electrode.

[0048] An unprecharged TQ anode was precharged using the method described in Figure 2 to fabricate an M-TQ anode. Specifically, the unprecharged TQ anode was placed in an electrochemical cell (see Figure 2) as the working electrode. A Pt plate (16 mm in diameter, 100 μm thick) was used as the counter electrode, and 1 mol / l aqueous solutions (LiCl aqueous solution, NaCl aqueous solution, MgCl2 aqueous solution, CaCl2 aqueous solution, ZnCl2 aqueous solution, AlCl3 aqueous solution, YCl3 aqueous solution) were used as the electrolytes. The reference electrode described in Figure 2 was used as the reference electrode.

[0049] Current density of 0.2 mA / cm² between the working electrode and the counter electrode. 2 A reduction current was applied, and discharge (insertion reaction of metal M ions) was carried out until the potential of the working electrode dropped to -0.8V (vs. Ag / AgCl).

[0050] Figure 3 shows the discharge curve when precharging was performed using the MgCl2 aqueous solution of Example 3. As shown in Figure 3, it was confirmed that an Mg-TQ anode with a capacity of approximately 500 mAh / g could be fabricated. This Mg-TQ anode was removed from the electrochemical cell and vacuum-dried at 100°C for 12 hours.

[0051] Similarly, with other electrolytes, we were able to create M-TQ negative electrodes with a charging capacity of approximately 500 mAh / g by pre-charging them.

[0052] Based on the above, the Li-TQ anode of Example 1, the Na-TQ anode of Example 2, the Mg-TQ anode of Example 3, the Ca-TQ anode of Example 4, the Zn-TQ anode of Example 5, the Al-TQ anode of Example 6, and the YC-TQ anode of Example 7 were fabricated.

[0053] (Preparation of the positive electrode) The positive electrode in this example contains 2,5-dimethoxy-1,4-benzoquinone (hereinafter referred to as DMBQ). DMBQ is an organic compound containing a carbonyl (C=O) group. The chemical formula of DMBQ is shown below.

[0054]

[0055] A commercially available DMBQ powder having this chemical structure, Ketjenblack powder, and polytetrafluoroethylene (PTFE) powder were thoroughly ground and mixed using a grinder in a weight ratio of 40:40:20. This mixture was then roll-formed to create a sheet electrode (thickness: 0.5 mm). The sheet electrode and the titanium mesh current collector were each cut into circles with a diameter of 16 mm. The circular sheet electrode was then pressed and compressed onto the circular titanium mesh to obtain a DMBQ positive electrode.

[0056] (Preparation of electrolyte) The electrolyte was prepared by mixing and stirring distilled water with a chloride compound (Example 1: LiCl, Example 2: NaCl, Example 3: MgCl2, Example 4: CaCl2, Example 5: ZnCl2, Example 6: AlCl3, Example 7: YCl3) to a concentration of 1.0 mol / L.

[0057] (Fabrication of secondary batteries) Secondary batteries were fabricated using the electrochemical cell shown in Figure 1. Both the positive and negative electrodes were fixed to titanium rods by spot welding, and the respective electrolytes were filled into the electrochemical cell. The secondary batteries of Examples 1 to 7 were then fabricated by fixing the positive and negative electrodes in their predetermined positions as shown in Figure 1.

[0058] (Battery Performance Measurement) The battery performance of each secondary battery prepared according to the above procedure was measured in a constant temperature chamber maintained at 30°C. The battery cycle test was performed using a charge / discharge measurement system (VMP-3, Bio Logic), with a current density of 0.1 mA / cm² per effective area of ​​the positive electrode. ２ The system was energized, and the discharge voltage was measured from the open-circuit voltage until the battery voltage dropped to 0V (discharge termination voltage).

[0059] Furthermore, the charging current density per unit area of ​​the positive electrode is 0.1 mA / cm². ２ The device was energized, and the charging termination voltage was set to 1.2V. The charge / discharge capacity was expressed as the value per unit weight (mAh / g) of the positive electrode active material (DMBQ).

[0060] (Battery Performance) Figure 4 shows the discharge curve for the first discharge (1st), the discharge curve for 10 cycles (10st), and the discharge curve for 30 cycles (30st) of Example 3.

[0061] Figure 5 shows the evaluation results of the battery performance for each embodiment. Specifically, it shows the initial average discharge voltage, initial discharge capacity, discharge capacity after 10 cycles, and discharge capacity after 30 cycles for Embodiments 1 to 7.

[0062] As shown in Figures 4 and 5, the initial discharge capacity of Example 3 was 165 mAh / g, and the initial average discharge voltage was 0.47 V. The average discharge voltage is defined as the battery voltage at half the total discharge capacity. The discharge capacities after 10 cycles and 30 cycles were 122 mAh / g and 101 mAh / g, respectively. Although a decrease in discharge capacity of approximately 1% per cycle was observed, the secondary battery of Example 3 was confirmed to function as a secondary battery capable of charge-discharge cycles.

[0063] In other embodiments as well, as shown in Figure 5, although a decrease in discharge capacity due to the cycle was observed in all embodiments, the operation as a secondary battery was confirmed.

[0064] <Examples 8-14> In these examples, secondary batteries were fabricated using electrochemical cells (see Figure 1). M-TQ prepared by precharging was used as the negative electrode, DMBQ was used as the positive electrode, and a propylene carbonate (PC) solution containing metal perchlorates (non-aqueous electrolyte) was used as the electrolyte to fabricate the secondary batteries.

[0065] The negative and positive electrodes of this embodiment were prepared in the same manner as in Examples 1 to 7. The secondary battery of this embodiment differs from the secondary batteries of Examples 1 to 7 in that it uses a non-aqueous electrolyte.

[0066] The non-aqueous electrolytes in these examples were prepared by vacuum-drying commercially available metal perchlorates (Example 8: LiClO4, Example 9: NaClO4, Example 10: Mg(ClO4)2, Example 11: Ca(ClO4)2, Example 12: Zn(ClO4)2, Example 13: Al(ClO4)2, Example 14: Y(ClO4)3) and dissolving them in lithium battery-grade PC solvent. All non-aqueous electrolytes were prepared to have a metal salt concentration of 0.5 mol / L.

[0067] The secondary battery in this embodiment was manufactured using the same method as in Examples 1 to 7.

[0068] The secondary batteries prepared using the above procedure were subjected to performance testing in a dry environment with a dew point of -60°C or lower (room temperature: 25°C). The battery cycle test was performed using a charge / discharge measurement system (VMP-3, Bio Logic), with a current density of 0.1 mA / cm² per effective area of ​​the positive electrode. ２ The battery was energized, and the discharge voltage was measured until the open-circuit voltage dropped to 2.0V (discharge termination voltage). Charging was performed with a current density of 0.1 mA / cm² per effective area of ​​the positive electrode. ２ The device was energized, and the charging termination voltage was set to 4.2V. The charge / discharge capacity was expressed as the value per unit weight (mAh / g) of the positive electrode active material (DMBQ).

[0069] Figure 6 shows the evaluation results of the battery performance for Examples 8 to 14. In all examples, it was confirmed that the initial discharge capacity and initial average discharge voltage were greater than when using an aqueous electrolyte (corresponding Examples 1 to 7). Furthermore, operation as a secondary battery was possible, and the decrease in discharge capacity with each cycle was comparable to that of the aqueous electrolyte.

[0070] [Comparative Examples 1-4] In these comparative examples, secondary batteries were fabricated using an aqueous electrolyte and a metal as the negative electrode. These comparative examples were compared with the examples using the corresponding M-TQ negative electrode and aqueous electrolyte. Note that lithium metal, sodium metal, and calcium metal react violently with water, so secondary batteries using these metals as the negative electrode were not fabricated in these comparative examples.

[0071] Specifically, secondary batteries were fabricated and evaluated using magnesium metal as the negative electrode in Comparative Example 1, zinc metal in Comparative Example 2, aluminum metal in Comparative Example 3, and yttrium metal in Comparative Example 4, and were compared with the secondary batteries of Examples 3, 5, 6, and 7. The electrolytes of Comparative Examples 1 to 4 were the same as those of Examples 3, 5, 6, and 7. The positive electrodes of Comparative Examples 1 to 4 were the same as those of Examples 3, 5, 6, and 7.

[0072] The negative electrode metal in this comparative example was prepared by rolling commercially available metal sheets or metal ingots into a sheet. All metal sheets used were approximately 100 μm thick and were pressed onto a titanium mesh to form the negative electrode. Furthermore, the battery configuration, manufacturing procedure, and experimental methods were the same as in Examples 3, 5, 6, and 7, which used an aqueous electrolyte.

[0073] Figure 7 shows the initial discharge capacity of the secondary battery in this comparative example and the discharge capacity after 10 charge-discharge cycles. In Comparative Examples 1 and 3, the discharge capacity after 10 cycles was zero, indicating that operation as a secondary battery is difficult. Furthermore, in Comparative Examples 2 and 4, a capacity decrease of approximately 80% and 70%, respectively, was observed. Specifically, the capacity retention rates for Comparative Examples 2 and 4 were 22% and 29%, respectively. It is clear that the capacity degradation in this comparative example is more significant than in Examples 3, 5, 6, and 7 (capacity retention rates of 74% to 87%) which used an M-TQ negative electrode.

[0074] The results of this comparative example confirm that secondary batteries using an M-TQ negative electrode and an aqueous electrolyte can operate as high-performance secondary batteries with less degradation associated with charge-discharge cycles than secondary batteries using a metal negative electrode and an aqueous electrolyte.

[0075] [Comparative Examples 5-11] In these comparative examples, secondary batteries were fabricated using a non-aqueous electrolyte and a metal negative electrode. These comparative examples were compared with Examples 8-14, which used the corresponding M-TQ negative electrode and non-aqueous electrolyte. In the non-aqueous electrolyte, lithium metal, sodium metal, and calcium metal, which were difficult to use in Comparative Examples 1-4, could also be used. Therefore, in these comparative examples, secondary batteries using lithium metal (Comparative Example 5), sodium metal (Comparative Example 6), magnesium metal (Comparative Example 7), calcium metal (Comparative Example 8), zinc metal (Comparative Example 9), aluminum metal (Comparative Example 10), and yttrium metal (Comparative Example 11) as negative electrodes were fabricated and evaluated, and compared with the secondary batteries of Examples 8-14.

[0076] The negative electrode metal was prepared by rolling commercially available metal sheets or metal ingots into a sheet. All metal sheets used were approximately 100 μm thick and were pressed onto a titanium mesh to form the negative electrode. Other battery configurations, manufacturing procedures, and experimental methods were the same as those used in Examples 8-14, which utilize a non-aqueous electrolyte.

[0077] Figure 8 shows the initial discharge capacity of the secondary battery in this comparative example and the discharge capacity after 10 charge-discharge cycles. In this comparative example, the discharge capacity retention rate after 10 cycles was about 20-30%, which is significantly lower than the discharge capacity retention rate of about 70-80% in Examples 8-14 using the M-TQ negative electrode. This clearly shows that the capacity degradation is more pronounced when using the metal negative electrode.

[0078] The results of this comparative example confirm that secondary batteries using an M-TQ negative electrode and a non-aqueous electrolyte can operate as high-performance secondary batteries with less degradation associated with charge-discharge cycles compared to those using a metal negative electrode and a non-aqueous electrolyte.

[0079] As described above, the secondary battery of this embodiment is a secondary battery with excellent charge and discharge characteristics without using a metal negative electrode, and can be effectively used as a new power source for various electronic devices such as small devices, sensors, and mobile devices.

[0080] This disclosure is not limited to the embodiments described above, and various modifications and combinations are possible within the technical concept of this disclosure.

[0081] 100: Electrochemical cell 101: Positive electrode 102: Electrolyte (electrolyte solution) 103: Negative electrode 104: Conductive material (current collector) 105: Titanium rod 200: Electrochemical cell 210: Working electrode 220: Counter electrode 230: Reference electrode 240: Electrolyte solution

Claims

1. A secondary battery comprising: a negative electrode containing triquinoxalinylene containing metal ions; a positive electrode containing a material capable of inserting and deinserting or adsorbing and desorbing the metal ions; and an electrolyte containing the metal ions disposed between the positive electrode and the negative electrode.

2. The secondary battery according to claim 1, wherein the metal constituting the metal ion includes one metal selected from the group consisting of Li, Na, Mg, Ca, Zn, Al, and Y.

3. The secondary battery according to claim 1 or 2, wherein the electrolyte is an aqueous electrolyte.

4. The secondary battery according to claim 1 or 2, wherein the electrolyte is a non-aqueous electrolyte.

Images