Aqueous iodine battery based on multi-electron transfer

Abstract

This application discloses a multi-electron transfer type aqueous iodine battery, the main structure of which includes a positive electrode, a negative electrode, a current collector, an electrolyte, and a separator. Both the positive and negative electrodes use porous carbon felt as the electrode material and a polymer membrane as the membrane material. The electrolytes of both the positive and negative electrodes are stored in the porous carbon felt electrodes. The electrolytes of both the positive and negative electrodes are I - and Cd 2+ During charging, the positive electrode I - is charged to Cd(IO3)2, and a six-electron transfer electrochemical reaction is realized. The negative electrode is Cd 2+ and is deposited as Cd metal, and the discharge process is reversed. The energy density of the battery, calculated based on the volume of the positive electrolyte, reaches about 1100 Wh / L. To improve the kinetics and reversibility of the multi-electron transfer process, other additives must be added to the solution to improve the electrochemical reversibility of the overall reaction, so that the battery can be discharged at up to 80 mA / cm 2 It can achieve an energy efficiency of over 77% at a current density of 1000 mA and can operate stably for 500 cycles.

Description

[Technical Field]

[0001] The present invention relates to the field of batteries, and in particular to the field of multi-electron transfer aqueous iodine batteries. [Background technology]

[0002] The massive use of fossil energy is causing environmental pollution and an energy crisis, and the development and use of renewable energy is key to solving these problems. The widespread use of electric vehicles is an important means of resolving the fossil energy crisis. Currently, electric vehicles mainly use lithium-ion batteries. Although lithium-ion batteries have a high energy density (approximately 300 Wh / L), their use of organic electrolytes can cause problems such as flammability and explosion. Aqueous batteries are expected to be used in a wide range of applications due to their high safety and high output density. However, current aqueous batteries generally have low energy densities, making them difficult to use in the field of power batteries. The applicant has discovered that in a strongly acidic environment, I in the electrolyte of the positive electrode - generates I2 through an electrochemical reaction, which then converts to IO3 - , completing a six-electron transfer, and - We have developed a multi-electron transfer aqueous iodine battery, which has the potential to dramatically increase the energy density of batteries due to its high solubility. However, the multi-electron transfer process faces serious electrochemical polarization problems. During the charging process, I2 is converted into IO3 - The electrochemical process for the production of IO3 requires the transfer of five electrons, and multiple H2O molecules are required to participate in the reaction. The symmetric I2 makes it difficult for the oxygen in the water molecule to attack its positive charge center, thus increasing the polarization of the charge reaction. On the other hand, in the discharge process, IO3 - Because of its stable structure and large volume, it is difficult to discharge directly on the electrode surface. - In oxidizing solution, I - However, the only way to achieve indirect discharge is to generate I2 from the - The electrode potential (0.54V vs. SHE) is IO3 - / I2 (1.19 V vs. SHE), severe polarization also occurs in the discharge process. Summary of the Invention

[0003] 1. A multi-electron transfer based aqueous iodine battery comprising a positive electrode electrolyte and a negative electrode electrolyte, The positive and negative electrode electrolytes are both Cd 2+ and I - A strongly acidic aqueous solution containing Br - and / or Cl - It contains an additive derived from

[0004] I for both the positive and negative electrolytes - are derived from one or more of HI, KI, NaI, or CdI2, respectively, and Cd 2+ The two electrolytes use one or both of CdI2 and CdSO4, respectively, and H2SO4 is selected as the supporting electrolyte in the electrolyte to ensure a strong acidic environment.

[0005] Cd in the positive or negative electrode electrolyte 2+ The molar concentrations of are 0.5 to 3M, respectively, and I - The molar concentration of Cd is 1-6M. 2+ and I - The molar ratio of H + The molar concentration of Cd is 3-12M. 2+ and I - The molar ratio is preferably 1:2.

[0006] During the charging process, the positive electrode I - IO3 generated by - is the Cd in solution 2+ With this, Cd(IO3)2 precipitates, which results in the oxidized charge product IO3 - This solves the problem of battery self-discharge due to the penetration of

[0007] To reduce the polarization problem in the electrochemical process, additives are added to the positive and negative electrolytes, respectively, and the additives are mainly Br- and / or Cl - The purpose is to introduce the Br - The additive from which is derived is one or more of NaBr, KBr, or HBr, and Cl - The additive from which is derived is one or more of NaCl, KCl, and HCl, and the concentration of the additive introduced is 1 to 3M.

[0008] Specific compositions of the positive electrode electrolyte and the negative electrode electrolyte are as follows: When HI with a concentration of 1 to 6 M (HI concentration is preferably 6 M) is used as the iodine-based active material, and HBr and / or HCl with a concentration of 1 to 3 M (additive concentration is preferably 3 M) is used as the additive, the concentration of the supporting electrolyte H2SO4 is 1 to 3 M (H2SO4 concentration is preferably 1 M), and the Cd active material is Cd(SO4)2 with a concentration of 1 to 3 M (CdSO4 concentration is preferably 3 M), Alternatively, when HI having a concentration of 1 to 6 M (HI concentration is preferably 6 M) is used as the iodine-based active material, and one or more of NaBr, KBr, NaCl, and KCl having a concentration of 1 to 3 M (additive concentration is preferably 3 M) are used as the additive, the concentration of the supporting electrolyte H2SO4 is 2 to 4 M (H2SO4 concentration is preferably 2 M), and the Cd active material is Cd(SO4)2 having a concentration of 1 to 3 M (CdSO4 concentration is preferably 3 M), Alternatively, when CdI2 with a concentration of 0.5 to 3 M (preferably the CdI2 concentration is 3 M) is used as the active material and HBr and / or HCl with a concentration of 1 to 3 M (preferably the additive concentration is 3 M) are used as the additive, the concentration of the supporting electrolyte H2SO4 is 2 to 4 M (preferably the H2SO4 concentration is 4 M), Alternatively, when CdI2 is selected as the active material at a concentration of 0.5 to 3 M (the CdI2 concentration is preferably 3 M) and one or more of NaBr, KBr, NaCl, and KCl are selected as the additive at a concentration of 1 to 3 M (the additive concentration is preferably 3 M), the concentration of the supporting electrolyte H2SO4 is maintained at 3 to 5 M (the H2SO4 concentration is preferably 5 M), Alternatively, when NaI and / or KI at a concentration of 1 to 6 M (NaI and / or KI concentration is preferably 6 M) are selected as the active material, and HBr and / or HCl at a concentration of 1 to 3 M (additive concentration is preferably 3 M) are selected as the additive, the concentration of the supporting electrolyte H2SO4 is 2 to 4 M (H2SO4 concentration is preferably 4 M), and the Cd active material is Cd(SO4)2 at a concentration of 1 to 3 M (CdSO4 concentration is preferably 3 M), Alternatively, when NaI and / or KI are selected as the active material at a concentration of 1 to 6 M (NaI and / or KI concentration is preferably 6 M) and one or more of NaBr, KBr, NaCl, and KCl are selected as the additive at a concentration of 1 to 3 M (additive concentration is preferably 3 M), the concentration of the supporting electrolyte H2SO4 is maintained at 3 to 5 M (H2SO4 concentration is preferably 5 M), and the Cd active material is Cd(SO4)2 at a concentration of 1 to 3 M (CdSO4 concentration is preferably 3 M).

[0009] The battery includes a positive electrode, a negative electrode, a membrane material, and an electrolyte, and both the positive electrode electrolyte and the negative electrode electrolyte are Cd 2+ and I - The electrolyte is a strongly acidic aqueous solution containing , and additives must be introduced into the electrolyte to improve the kinetics and reversibility during the electrochemical reaction. The membrane material of the battery is one or more polymer materials selected from PES, PVC, PSF, PE, and Nafion, preferably Nafion resin.

[0010] A battery includes a single cell or a stack, and a single cell is configured by sequentially stacking a positive end plate, a positive current collector, a positive carbon felt electrode impregnated with a positive electrolyte, a separator, a negative carbon felt electrode impregnated with a negative electrolyte, a negative current collector, and a negative end plate, and a stack is a circuit of two or more single cells connected in series and / or parallel.

[0011] During battery charging, the I in the positive electrode electrolyte - On the porous electrode, I2 is generated, and as charging progresses, an iodine interhalogen compound, such as IBr / ICl, is generated. As charging continues, IO3 - is generated, and Cd 2+Cd(IO3)2 is formed with Cd in the negative electrode electrolyte. 2+ is reduced to metallic Cd. In the discharge process of the positive electrode, Cd(IO3)2 is indirectly discharged through chemical oxidation-electrochemical reaction, and finally discharged to I - is produced, while the discharge reaction at the negative electrode converts metallic Cd to Cd 2+ is generated. [Effects of the Invention]

[0012] The beneficial effects of the present invention are as follows: In the present invention, other halogen ions (Br - or Cl - By introducing halogens such as IBr and Br2 into the electrolyte as additives, the electrochemical activity and reversibility of the electrolyte can be significantly improved. Halogens with different electronegativities (I2 and Br2, or I2 and Cl2) form interhalogen compounds (IBr / ICl), which promote the attack on the positive charge center of water molecules, thereby reducing the polarization of the charge. For example, Cl - or Br - When I2 is introduced into the solution as an additive, I2 reacts with Br2 or Cl2 to form interhalogen compounds such as ICl and IBr in the electrochemical reaction process. Compared with the symmetric molecule I2, the positive charges of ICl and IBr are mainly concentrated on the iodine atoms. Therefore, during the charging process, the oxygen atoms of H2O are more likely to attack them, resulting in the formation of IO3 - The generated IO3 - is Cd 2+ and Cd(IO3)2, thereby forming IO3 - This avoids the self-discharge caused by the penetration of IO3 - is Cl - / Br - Indirect discharge can be achieved by chemical oxidation of other halogen ions such as IBr, Br2 or ICl, Cl2 to generate IBr, Br2 or ICl, Cl2, and then reducing IBr, Br2 or ICl, Cl2 on the electrode surface. Also, the more electronegative the halogen, the higher the electrode potential, e.g., Br2 / Br -The electrode potential is about 1.08 V, and I2 / IO3 - This is slightly lower than the electrode potential of 1.19 V, and therefore, IO3 - Br - can be easily oxidized to elemental bromine, and the potential difference between the two is relatively small (IO3 - / I2 (1.19V vs. SHE) and I2 / I - This system effectively reduces the discharge polarization of the battery. - / IO3 - By realizing a reversible six-electron transfer reaction, the number of electron transfers is increased, and by combining it with a highly concentrated electrolyte, extremely high energy density can be obtained. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a structural schematic diagram of a multi-electron transfer aqueous iodine battery system. [Figure 2] This figure shows the charge / discharge curves and cycle characteristics of the battery assembled in Example 1. The electrolyte composition is 0.5MCdI2 + 3MH2SO4 + 1MHBr. The operating current density of the battery is 80 mA / cm2, and the membrane material is a Nafion 115 membrane. At a current density of 80 mA / cm2, the battery has an energy density of over 220 Wh / L and an energy efficiency of over 77%. It can also operate stably for over 500 cycles while maintaining an energy density of 100 Wh / L. The battery mainly comprises a positive end plate, a positive current collector, a positive electrode, a separator, a negative electrode, a negative current collector, and a negative end plate. The battery test conditions were a dual voltage and capacity termination for charge termination, a 0.1 V voltage termination, and a constant current charge / discharge process. [Figure 3]This figure shows the charge / discharge curves and cycle characteristics of the battery assembled in Example 2. The electrolyte composition is 1MCdI2 + 3MH2SO4 + 2MHBr. The operating current density of the battery is 80 mA / cm2, and the membrane material is a Nafion 115 membrane. At a current density of 80 mA / cm2, the battery has an energy density of over 350 Wh / L and an energy efficiency of over 77%. It can also operate stably for over 400 cycles while maintaining an energy density of 220 Wh / L. [Figure 4] This figure shows the charge / discharge curves and cycle characteristics of the battery assembled in Example 3. The electrolyte composition is 3MCdI2 + 3MH2SO4 + 3MHBr, and the membrane material is Nafion115 membrane. The battery achieves an energy density of over 1100 Wh / L at 40 mA / cm2, with an energy efficiency of over 75%. [Figure 5] This figure shows the charge / discharge curves and cycle characteristics of the battery assembled in Example 4. The electrolyte composition is 3MHI + 1.5MCdSO4, + 3MH2SO4 + 3MHBr, and the membrane material is Nafion115 membrane. The battery achieves an energy density of over 490 Wh / L at 80 mA / cm2, an energy efficiency of over 76%, and can operate stably for over 120 cycles while maintaining an energy density of 320 Wh / L. [Figure 6] 1 shows the charge / discharge curves for the battery assembled in Example 5. The electrolyte composition is 1M CdI + 3M HSO + 2M NaBr, and the membrane material is a Nafion 115 membrane. The battery achieves an energy density of over 350 Wh / L at 80 mA / cm, with an energy efficiency of over 76%. [Figure 7] Figure 6 shows the characteristics of the battery assembled in Example 6. The electrolyte composition is 1M CdI2, + 3M M H2SO4 + 2M NaCl, with Cl- instead of Br- as an additive, and the membrane material is Nafion 115. The battery achieves an energy density of over 340 Wh / L at 80 mA / cm2, with an energy efficiency of over 76%. [Figure 8]Figure 1 shows the performance of the battery assembled in Example 7. The electrolyte composition is 1MCdI2 + 3MH2SO4 + 2MHCl, and the membrane material is a Nafion 115 membrane. The battery achieves an energy density of over 345 Wh / L at 80 mA / cm2, with an energy efficiency of over 76%. [Figure 9] 1 shows the characteristics of a battery assembled in Example 1. The electrolyte composition is 6MHI+3MHBr+1MHSO+3MCdSO, and the membrane material is Nafion 115. The battery achieves an energy density of over 1050 Wh / L at 80 mA / cm, with an energy efficiency of over 74%. [Figure 10] 1 shows the characteristics of a battery assembled in Example 2. The electrolyte composition is 6MHI+3MKCl+2MHSO+3MCdSO, and the membrane material is Nafion 115. The battery achieves an energy density of over 1020 Wh / L at 80 mA / cm, with an energy efficiency of over 75%. [Figure 11] 1 shows the characteristics of a battery assembled in Example 3. The electrolyte composition is 6M NaI + 3MHBr + 4MHSO + 3MCdSO, and the membrane material is Nafion 115. The battery achieves an energy density of over 1060 Wh / L at 80 mA / cm, with an energy efficiency of over 74%. [Figure 12] 1 shows the characteristics of a battery assembled in Example 4. The electrolyte composition is 6M NaI + 3M NaBr + 5M H2SO4 + 3M CdSO4, and the membrane material is a Nafion 115 membrane. The battery achieves an energy density of over 1045 Wh / L at 80 mA / cm2 and an energy efficiency of over 76%. [Figure 13] 1 shows the characteristics of a battery assembled in Example 5. The electrolyte composition is 6MKI+3MHBr+4MHSO+3MCdSO, and the membrane material is Nafion115. The battery achieves an energy density of over 1074 Wh / L at 80 mA / cm, with an energy efficiency of over 74%. [Figure 14]1 shows the characteristics of a battery assembled in Example 6. The electrolyte composition is 6MKI+3MHBr+4MHSO+3MCdSO, and the membrane material is Nafion115. The battery achieves an energy density of over 1022 Wh / L at 80 mA / cm, with an energy efficiency of over 74%. [Figure 15] This figure shows a characteristic test of the multi-electron transfer iodine battery assembled in Comparative Example 1. The electrolyte composition was 0.5MCdI2 + 3MH2SO4, the operating current density of the battery was 80mA / cm2, and the membrane material was Nafion115 membrane. However, the battery had very large polarization, and the energy efficiency was only 57%. Due to the effects of polarization, the energy density of the battery was low, at only 114Wh / L. [Figure 16] This figure shows the characteristics test of the multi-electron transfer iodine battery assembled in Comparative Example 2. The electrolyte composition was 0.5MCdI2 + 3MH2SO4 + 0.1MHBr, the battery's operating current density was 80mA / cm2, and the membrane material was Nafion115. Due to the low HBr concentration, the battery polarization was large, the energy efficiency was only 54%, and the battery's energy density was limited to only 104Wh / L. [Figure 17] This figure shows the characteristics of the battery assembled in Comparative Example 3. The electrolyte composition was 1MHI + 3M H2SO4 + 1M HBr + 0.2M CdSO4. The operating current density of the battery was 80 mA / cm2, and the membrane material was a Nafion 115 membrane. Because the Cd2+:I- ratio in the solution was 1:5, the generated IO3- could not form Cd2+ and Cd(IO3)2 precipitates, resulting in serious mixing of the electrolyte. Therefore, the battery's coulombic efficiency was low, the battery's energy efficiency was close to 60%, and the battery's energy density was only about 103 Wh / L. [Figure 18]This figure shows the performance test of the battery assembled in Comparative Example 4. The electrolyte composition is 0.5M CdI2 + 1M HBr. The operating current density of the battery is 80mA / cm2, and the membrane material is Nafion 115 membrane. Although HBr is added as an additive, the low H+ concentration in the solution affects the chemical reaction rate of IO3 - to Br- oxidation, which negatively impacts the energy efficiency of the battery. Test results showed that the battery had an energy efficiency of only 65% ​​at 80mA / cm2 and an energy density below 150Wh / L. [Figure 19] This figure shows the characteristic test of the battery assembled in Comparative Example 5. The electrolyte composition is 0.5MCdI2 + 0.5MH2SO4 + 1MHBr. The operating current density of the battery is 80mA / cm2, and the membrane material is Nafion115 membrane. As in Comparative Example 4, HBr is added as an additive and H2SO4 is added as a supporting electrolyte. However, because the H+ concentration is still low, the reaction rate of IO3 - oxidizing Br- is slow. Therefore, the polarization of the battery is still large, and the battery efficiency is only 70%. [Figure 20] This figure shows the characteristic test of the battery assembled in Comparative Example 6. The electrolyte composition is 0.1M CdI2 + 3M H2SO4 + 1M HBr. The operating current density of the battery is 80 mA / cm2, and the membrane material is Nafion 115 membrane. However, in this electrolyte system, the concentration of CdI2 is low, so the amount of IO3- produced is small. During the discharge process, it is difficult to achieve indirect discharge by chemically reacting with Br-. Therefore, the polarization of the battery remains large. The test results showed that the energy efficiency of the battery at 80 mA / cm2 is only 64%. [Figure 21]This figure shows the characteristic test of the battery assembled in Comparative Example 7. The electrolyte composition is 0.5MCdI2 + 3MH2SO4 + 1MHBr. The operating current density of the battery is 80mA / cm2, and the membrane material is a porous PE membrane. Compared to the Nafion 115 membrane, the porous PE membrane has a lower blocking ability to the positive electrode charging product, which results in serious penetration of the positive electrode electrolyte and very low coulombic efficiency of the battery. Battery testing results show that the energy density of the battery is only 52%. [Figure 22] This figure shows the performance test of the battery assembled in Comparative Example 8. The electrolyte composition was 1MHI + 3MH2SO4 + 1MTiOSO4. The operating current density of the battery was 80 mA / cm2, and the membrane material was a Nafion 115 membrane. Compared to the Cd2+ / Cd anode, when Ti3+ / Ti4+ was used as the battery anode, the battery performance was very poor. This is mainly due to the low activity of TiO(IO3)2, which is generated from IO3- and TiO2+, and is difficult to oxidize Br-. The energy efficiency of the battery was only 32%. DETAILED DESCRIPTION OF THE INVENTION

[0014] In the characteristic test of the multi-electron transfer aqueous iodine battery, the charging current density was 80mA / cm 2 The battery's charge cut-off voltage is 2.4 V or one or two of the specific capacities, the discharge cut-off voltage is 0.1 V, and the carbon felt on both sides of the positive and negative electrodes is 1 mm, and its area is 48 cm. 2 The volume of the electrolyte on the positive electrode side is 5 mL, and the volume of the electrolyte on the negative electrode side is 15 mL. The electrolytes on both the positive and negative electrodes are also adsorbed inside the porous carbon felt. The membrane material required for the battery is Nafion 115 membrane. The electrolytes on the positive and negative electrodes are the same.

[0015] Figures 2-5 (Examples 1-4) show the charge / discharge curves and cycle characteristics of the battery under optimal conditions. As the electrolyte concentration increases, the battery's energy density increases from 220 Wh / L to 1100 Wh / L at 1 M. Furthermore, when charging and discharging while maintaining a constant capacity of four electrons, the battery operated stably for up to 500 cycles.

[0016] Compared with the electrolyte solution containing HBr as an additive, higher electrochemical activity can also be obtained by replacing HBr in the solution with NaBr, HCl, or NaCl (Examples 5-7 correspond to Figures 6-8). This is mainly because the iodine interhalogen compound IBr / ICl is also formed during the charging process, thereby reducing the charging polarization. Regarding the discharging process, IO3 - Br - / Cl - The additives can be used to oxidize the electrolyte, thereby achieving indirect discharge and increasing the discharge voltage of the battery, and the energy efficiency of the electrolyte system using the additives can exceed 75%.

[0017] When the electrolyte concentration is increased to 6M (the most preferred electrolyte composition, preferred examples 1 to 6 correspond to Figures 9 to 14), the energy density of the battery becomes approximately 1100 Wh / L and the energy efficiency exceeds 74%, indicating that the most preferred electrolyte has a significant advantage in terms of energy density.

[0018] Compared with the electrolyte systems with additives, electrolytes with low additive concentrations or no additives added exhibit severe polarization, degrading battery performance (Comparative Examples 1-2, Figures 15-16), and battery energy efficiency of less than 60%.

[0019] High concentrations of Cd 2+ Compared with the electrolyte system containing Cd 2+ Because of its low concentration, IO3 in solution - At the same time, the precipitate cannot be completely formed, resulting in serious self-discharge of the battery, deterioration of the battery characteristics (Comparative Example 3, FIG. 17), and the energy efficiency of the battery is less than 60%.

[0020] H in solution + When the concentration is reduced, the battery performance also deteriorates, mainly due to the H + The decrease in concentration of IO3 in the electrolyte - The oxidizing power of Br in the solution is reduced. -The main problem is that the rate at which the oxide is oxidized becomes slower (Comparative Examples 4 and 5, FIGS. 18 and 19).

[0021] I in solution - The efficiency of the battery also drops significantly when the concentration of I - As the concentration decreases, the IO3 - Br - or Cl - This is because the rate of the chemical oxidation process is limited, resulting in a battery energy efficiency of only about 64% (Comparative Example 6, Figure 20).

[0022] The Nafion 115 membrane was replaced with a PE polyolefin porous membrane. Due to the serious mixing of the electrolytes, the coulombic efficiency of the battery was very low (Comparative Example 7, FIG. 21). Battery Cd 2+ / Cd negative electrode Ti 3+ / Ti 4+ When replaced with I - IO3 produced by oxidation - and TiO 2+ TiO(IO3)2 is generated by TiO(IO3)2, and Br - or Cl - The slow chemical oxidation rate of the battery resulted in lower efficiency and lower energy density (Comparative Example 8, FIG. 22).

[0023] [Table 1]

[0024] [Table 2]

[0025] [Table 3]

[0026] The above are merely some examples of the present application, and are not intended to limit the present application in any way. Although the present application has been disclosed above with preferred embodiments, these are not intended to limit the present application. Those skilled in the art will recognize that, within the scope of the technical solutions of the present application, slight changes or modifications made using the technical content disclosed above are equivalent to equivalent embodiments, and all fall within the scope of the technical solutions.

Claims

1. 1. A multi-electron transfer based aqueous iodine battery comprising a positive electrode electrolyte and a negative electrode electrolyte, The positive and negative electrode electrolytes are both Cd ２＋ and I － a strongly acidic aqueous solution containing Br － and / or Cl － and an additive derived from The molar concentration of Cd 2+ in the positive electrode electrolyte or the negative electrode electrolyte is 0.5 to 3 M, the molar concentration of I − is 1 to 6 M, the molar ratio of Cd 2+ to I − is 1:2 to 1:1, and the molar concentration of H + is 3 to 12 M, An aqueous iodine battery based on multi-electron transfer, characterized in that:

2. I in both the positive and negative electrolytes － are HI, KI, NaI, or CdI, respectively. ２ Cd ２＋ are CdI, respectively. ２ , or CdSO ４ One or two of these are used, and the supporting electrolyte in the electrolyte is H ２ SO ４ 2. The battery of claim 1, wherein:

3. In the charging process, the positive electrode I － IO generated by ３ － is the Cd concentration in the solution ２＋ Together with Cd(IO ３ ) ２ A precipitate is formed, thereby forming the oxidized charge product IO. ３ － 2. The battery of claim 1, wherein the battery solves the problem of self-discharge of the battery due to the penetration of

4. The Br － The additive from which is derived is one or more of NaBr, KBr, or HBr, and Cl － The battery according to claim 1, characterized in that the additive from which the formula (I) is derived is one or more of NaCl, KCl, or HCl, and the concentration of the additive introduced is 1 to 3M.

5. Specific compositions of the positive electrode electrolyte and the negative electrode electrolyte are as follows: When 1 to 6 M HI is used as the iodine-based active material and 1 to 3 M HBr and / or HCl is used as the additive, the supporting electrolyte H ２ SO ４ The concentration of Cd is 1 to 3M, and the active material of Cd is Cd(SO ４ ) ２ and Alternatively, when HI with a concentration of 1 to 6 M is used as the iodine-based active material and one or more of NaBr, KBr, NaCl, and KCl with a concentration of 1 to 3 M is used as the additive, the supporting electrolyte H ２ SO ４ The concentration of Cd is 2-4M, and the active material of Cd is Cd(SO ４ ) ２ and Alternatively, CdI at a concentration of 0.5 to 3 M as the active material ２ When HBr and / or HCl having a concentration of 1 to 3 M is used as an additive, the supporting electrolyte H ２ SO ４ The concentration of is 2-4M, Alternatively, CdI at a concentration of 0.5 to 3 M as the active material ２ is selected and one or more of NaBr, KBr, NaCl, and KCl are selected as additives at a concentration of 1 to 3M, the supporting electrolyte H ２ SO ４ The concentration of is maintained at 3-5M, Alternatively, when NaI and / or KI at a concentration of 1 to 6 M are selected as the active material and HBr and / or HCl at a concentration of 1 to 3 M are selected as the additive, the supporting electrolyte H ２ SO ４ The concentration of Cd is 2-4M, and the active material of Cd is Cd(SO ４ ) ２ and Alternatively, when NaI and / or KI having a concentration of 1 to 6 M is selected as the active material and one or more of NaBr, KBr, NaCl, and KCl having a concentration of 1 to 3 M is selected as the additive, the supporting electrolyte H ２ SO ４ The concentration of Cd was maintained at 3-5M, and the active material was Cd(SO) at a concentration of 1-3M. ４ ) ２ 2. The battery according to claim 1, wherein:

6. The cathode, anode, membrane material, and electrolyte are both Cd ２＋ and I － and an additive must be introduced into the electrolyte to improve the kinetics and reversibility during the electrochemical reaction. The membrane material of the battery is one or more polymeric materials selected from the group consisting of PES, PVC, PSF, PE, and perfluorosulfonic acid-based polymers.

7. 10. The battery of claim 1, comprising a cell or stack, wherein a cell comprises, stacked in sequence, a positive end plate, a positive current collector, a positive carbon felt electrode impregnated with a positive electrolyte, a separator, a negative carbon felt electrode impregnated with a negative electrolyte, a negative current collector, and a negative end plate, and the stack is a circuit of two or more cells connected in series and / or parallel.

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