Neutral Zinc Manganese Secondary Battery and Electrolyte

Abstract

The neutral zinc manganese battery includes a neutral zinc manganese flow battery and a power battery. The flow battery includes positive electrode, negative electrode, electrolyte and membrane. The corresponding flow battery includes positive and negative pumps, pipelines and storage tanks. For the power battery, the electrolyte is stored in the porous electrode, while for the flow battery, the positive and negative electrolyte flows through the positive and negative electrodes through the pump and pipeline and finally returns to the storage tank to realize the circulation of electrolyte in the electrode chamber and storage tank. In addition, the positive and negative electrode electrolyte is a neutral solution of zinc salt and manganese salt with specific composition. During charging, MnO.sub.2 of the positive electrode can be oxidized directly to α-MnO.sub.2. During discharge, MnO.sub.2 dissolves into Mn.sup.2+.

Claims

1. A neutral zinc manganese secondary battery, which is characterized in that it comprises a positive electrolyte and a negative electrolyte; the positive and negative electrolyte have the same composition and are aqueous solutions containing zinc ions and manganese ions; the anions in the aqueous solution include acetate ions; the pH range of the electrolyte is 4-6, preferably pH=5.

2. The neutral zinc manganese secondary battery according to claim 1, which is characterized in that the preparation process of positive and negative electrolyte is to co-dissolve manganese salt and zinc salt in water to form a mixed aqueous solution of zinc salt and manganese salt to obtain the required positive and negative electrolyte; the manganese salt is manganese acetate or/and manganese chloride, the zinc salt is zinc acetate or/and zinc chloride, the positive active material is manganese acetate or/and manganese chloride, and the negative active material is zinc acetate or/and zinc chloride.

3. The neutral zinc manganese secondary battery according to claim 1, which is characterized in that the molar concentration of zinc ion in the positive and negative electrolyte is 0.1-1.5 M, preferably 0.5-1.2 M, more preferably 1 M; the molar concentration of manganese ion is 0.1-1.5 M, preferably 0.5-1.2 M, more preferably 1 M; the molar concentration of acetate ion is 0.1-6 M, preferably 3-5 M, more preferably 4 M; the molar concentration of chloride ion is 0-3M, preferably 0.5-2 M, more preferably 1.5-2 M.

4. The neutral zinc manganese secondary battery according to claim 1, which is characterized in that the electrolyte also comprises a supporting electrolyte, one or more of the supporting electrolytes KAc, KCl, K.sub.2SO.sub.4, NH.sub.4Cl, (NH.sub.4).sub.2SO.sub.4, with a concentration of 1-3 M.

5. The zinc manganese secondary battery according to claim 3, which is characterized in that the molar ratio of manganese salt to zinc salt is 0.5:1-3:1, preferably 0.8:1-1.5:1, more preferably 1:1; the ratio of acetate anion to manganese ion is 6:1-1:1, preferably 3:1-5:1, more preferably 4:1.

6. The zinc manganese secondary battery according to claim 1 which is characterized in that it also comprises a positive electrode and a negative electrode; the positive and negative electrodes are based on carbon felt, and the composite porous electrode is prepared by coating activated carbon on one or both sides of the positive substrate by scraping or impregnation; the activated carbon material is one or more of super P, carbon black, carbon nanotube or Keqin black, preferably super P; the loading amount is 2-20 mg/cm.sup.2, preferably 10-15 mg/cm.sup.2, more preferably 12 mg/cm.sup.2.

7. The zinc manganese secondary battery according to claim 1, which is characterized in that it further comprises a membrane between the positive electrode and the negative electrode, the zinc manganese secondary battery membrane material is a porous composite membrane coated with polymer resin, and the composite membrane substrate is a porous membrane prepared from one or more polymers of PES, PVC, PSF or PE; A polymer coating is coated on the surface of the porous substrate close to the surface of the positive electrode, and the polymer resin is one or more of SPEEK, PBI or Nafion, wherein the base material is preferably PE polymer, and the coating polymer resin is preferably Nafion resin; the pore diameter of the composite membrane substrate is 10-50 nm and the porosity is 30-60%.

8. The zinc manganese secondary battery according to claim 1, which is characterized in that the battery is liquid-solid conversion in the charging and discharging process, during the charge process, the electrochemical reaction of the positive electrode is Mn.sup.2+ to generate MnO.sub.2, the generated MnO.sub.2 is deposited on the porous electrode, the negative electrode is Zn.sup.2+ deposited with the form of Zn on the porous electrode; during the discharge process, MnO.sub.2 of the positive electrode is dissolved into Mn.sup.2+, and Zn deposited on the negative electrode is oxidized into Zn.sup.2+.

9. The zinc manganese secondary battery according to claim 1, which is characterized in that the zinc manganese secondary battery comprises a zinc manganese battery or a zinc manganese flow battery; the structure of Zn—Mn battery includes positive electrode, negative electrode, membrane, positive electrolyte and negative electrolyte; the zinc manganese flow battery is composed of a power stack, which composed of one single cell or more than two single cells in series and/or in parallel; the single cell comprises a positive end plate, a positive current collector, a positive electrode, a membrane, a negative electrode, a negative current collector, a negative end plate, a positive and negative electrolyte storage tank equipped with positive and negative electrolytes and a pump.

10. An electrolyte for neutral zinc manganese secondary battery, which is characterized in that the composition of positive and negative electrolyte is the same, both of which are aqueous solutions containing zinc ions and manganese ions, the anions in the aqueous solution include acetate ions, and the pH range of the electrolyte is 4-6, preferably pH=5; the molar concentration of zinc ion in the positive and negative electrolyte is 0.1-1.5 M, preferably 0.5-1.2 M, more preferably 1 M; the molar concentration of manganese ion is 0.1-1.5 M, preferably 0.5-1.2 M, more preferably 1 M; the molar concentration of acetate ion is 0.1-6 M, preferably 3-5 M, more preferably 4 M; the molar concentration of chloride ion is 0-3 M, preferably 0.5-2 M, more preferably 1.5-2 M; the molar ratio of manganese salt to zinc salt is 0.5:1-3:1, preferably 0.8:1-1.5:1, more preferably 1:1; the ratio of acetate anion to manganese ion is 6:1-1:1, preferably 3:1-5:1, more preferably 4:1.

Description

DESCRIPTION OF DRAWINGS

[0022] FIG. 1 is the structural diagram of zinc manganese secondary battery (including flow battery and battery).

[0023] FIG. 2 is a cycle performance diagram of the zinc manganese flow battery assembled in embodiment 1. The composition of electrolyte is 0.5 M manganese acetate, 0.5 M zinc acetate, supporting electrolyte 2 M KCl. The working current density of the battery is 40 mA/cm.sup.2. The electrode is a carbon felt electrode coated with super P with a load of 12 mg/cm.sup.2. The membrane material is composite membrane (PE is the substrate with Nafion resin as coating).

[0024] FIG. 3 is a cycle performance diagram of the zinc manganese flow battery assembled in embodiment 2. The electrolyte consists of lm manganese acetate, lm zinc chloride, 2 M KCl was employed as supporting electrolyte. The working current density of the battery is 40 mA/cm.sup.2. Carbon felt electrode coated with super P, with a load of 12 mg/cm.sup.2 was used as electrode. The membrane material is composite membrane (PE is the substrate with Nafion resin as coating).

[0025] FIG. 4 is a cycle performance diagram of the zinc manganese flow battery assembled in embodiment 3. The electrolyte consists of 1.5 M manganese acetate and 1.5 M manganese acetate, supporting electrolyte is 2 M KCl. The working current density of the battery is 40 mA/cm.sup.2. Carbon felt electrode coated with super P, with a load of 12 mg/cm.sup.2 was used as electrode. The membrane material is composite membrane (PE is the substrate with Nafion resin as coating).

[0026] FIG. 5 shows the cycle performance of the zinc manganese flow battery assembled in embodiment 4. The electrolyte consists of 1 M manganese chloride, 1 M zinc chloride, 2 M KCl. The working current density of the battery is 40 mA/cm.sup.2. Carbon felt electrode coated with super P, with a load of 12 mg/cm.sup.2 was used as electrode. The membrane material is composite membrane (PE is the substrate with Nafion resin as coating).

[0027] FIG. 6 is a cycle performance diagram of the zinc manganese flow battery assembled in embodiment 8. The electrolyte consists of 1 M manganese acetate, 1 M zinc acetate, 2 M KCl and 2 M KAc. The working current density of the battery is 40 mA/cm.sup.2. Carbon felt electrode coated with super P, with a load of 12 mg/cm.sup.2 was used as electrode. The membrane material is composite membrane (PE is the substrate with Nafion resin as coating).

[0028] FIG. 7 is a cycle performance diagram of the zinc manganese flow battery assembled in embodiment 9. The electrolyte consists of 1 M manganese acetate, 1 M zinc acetate, 0.5 M zinc chloride, and the supporting electrolyte is 2 M KCl. The operating current density of the battery is 40 mA/cm.sup.2, the electrode is carbon felt electrode, the electrode is coated with super P, and the loading capacity is 12 mg/cm.sup.2. The membrane material is composite membrane (PE is the substrate with Nafion resin as coating)

[0029] FIG. 8 is a cycle performance diagram of the zinc manganese flow battery assembled in embodiment 10. The composition of electrolyte is 1 M manganese acetate, 1 M zinc acetate, 1 M zinc chloride, and the supporting electrolyte is 2 M KCl. The operating current density of the battery is 40 mA/cm.sup.2, the electrode is carbon felt electrode coated with super P with the loading capacity is 12 mg/cm.sup.2. The membrane material is composite membrane (PE is the substrate with

[0030] Nafion resin as coating). FIG. 9 is a cycle performance diagram of the zinc manganese flow battery assembled in embodiment 11. The electrolyte consists of 1 M manganese acetate, 1 M zinc acetate, supporting electrolyte 2 M KCl. Adjust pH to 1, and the working current density of the battery is 40 mA/cm.sup.2. The positive electrode is coated with super P with a load of 12 mg/cm.sup.2. The membrane material is composite membrane (PE is the substrate with Nafion resin as coating).

[0031] FIG. 10 shows the cycle performance of the zinc manganese flow battery assembled in embodiment 14. The electrolyte consists of 1 M manganese acetate, 1 m zinc acetate, supporting electrolyte is 2 M KCl. Adjust pH to 14, the working current density of the battery is 40 mA/cm.sup.2, the electrode is carbon felt coated with super P with the loading capacity of 12 mg/cm.sup.2. The membrane material is composite membrane (PE is the substrate with Nafion resin as coating).

[0032] FIG. 11 shows the cycle performance of the zinc manganese flow battery assembled in embodiment 15. The electrolyte consists of 1 M manganese sulfate, 1 M zinc sulfate, supporting electrolyte is 1 M potassium sulfate. The working current density of the battery is 40 mA/cm.sup.2. The electrode is a carbon felt electrode, coated with Cochin black, with a load of 12 mg/cm.sup.2. The membrane material is composite membrane (P PE is the substrate with Nafion resin as coating).

[0033] FIG. 12 shows the cycle performance of the zinc manganese flow battery assembled in proportion 17. The electrolyte consists of 1 M manganese acetate, 1 M manganese chloride, supporting electrolyte is 2 M KCl. The working current density of the battery is 40 mA/cm.sup.2, and the electrode is coated with Super P with a load of 4 mg/cm.sup.2. The membrane material is a composite membrane (PE is the substrate with Nafion resin as coating).

[0034] FIG. 13 is the charge-discharge curve and cycle performance diagram of the zinc manganese flow battery assembled in embodiment 20. Electrolyte composition is: 1 M manganese acetate, 1 M zinc acetate, and the supporting electrolyte is 2 M KCl. Operating current density of battery is 40 mA/cm.sup.2, the electrode is coated with super P, and the loading capacity is 20 mg/cm.sup.2. The membrane material is composite membrane (PE is the substrate with Nafion resin as coating).

[0035] FIG. 14 is a cycle performance diagram of the zinc manganese flow battery assembled in embodiment 21. The electrolyte consists of 1 M manganese acetate, 1 M zinc acetate, supporting electrolyte is 2 M KCl. The working current density of the battery is 40 mA/cm.sup.2, and the electrode is coated with super P with a load of 12 mg/cm.sup.2. The membrane material is a composite membrane (PE is the substrate with Nafion resin as coating)

[0036] FIG. 15 is a cycle performance diagram of the battery assembled in embodiment 24. The electrolyte consists of 1 M manganese acetate and 1 M zinc acetate, supporting electrolyte is 2M KCl. The working current density of the battery is 40 mA/cm.sup.2, and the electrode is coated with super P with the loading capacity is 12 mg/cm.sup.2. The membrane material is a composite membrane (PE is the substrate with Nafion resin as coating).

[0037] FIG. 16 is a cycle performance diagram of the battery assembled in embodiment 2 of the zinc manganese battery. The electrolyte consists of 1 M manganese acetate, 1 M zinc acetate, supporting electrolyte is 2 M KCl. The working current density of the battery is 20 mA/cm.sup.2, and the current is 40 mA/cm.sup.2. The electrode is coated with super P with a load of 12 mg/cm.sup.2. The membrane material is composite membrane (PE is the substrate with Nafion resin as coating)

[0038] FIG. 17 is a cycle performance diagram of the battery assembled in comparative Example 1 of the zinc-manganese flow battery. The electrolyte composition is 0.5 M manganese sulfate, 0.5 M zinc sulfate, supporting electrolyte is 0.5 M K.sub.2SO.sub.4. The operating current density of the battery is 40 mA/cm.sup.2, coated with super P on the electrode, with a load of 12 mg/cm.sup.2. The membrane material is composite membrane (PE is the substrate with Nafion resin as coating).

[0039] FIG. 18 shows the cycle performance of the zinc manganese battery to the battery assembled in comparative Example 2. Electrolyte composition is 0.5 M manganese acetate, 0.5 M zinc acetate, supporting electrolyte is 2 M KCl. The operating current density of the battery is 20 mA/cm.sup.2. No coating is applied to the electrode. The membrane material is a composite membrane (PE is the substrate with Nafion resin as coating).

[0040] FIG. 19 shows the cycle performance of zinc manganese battery to the battery assembled in comparative Example 3. The electrolyte composition is 0.5 M manganese acetate, 0.5 M zinc acetate, supporting electrolyte is 2 M KCl. The operating current density of the battery is 40 mA/cm.sup.2, the electrode is coated with super P with a loading capacity of 12 mg/cm.sup.2. The membrane material is composite membrane (PE is the substrate with Nafion resin as coating).

[0041] FIG. 20 shows the cycle performance of zinc manganese battery to the battery assembled comparative Example 4. The electrolyte composition is 0.5 M manganese acetate, 0.5 M zinc acetate, supporting electrolyte is 2 M KCl. The operating current density of the battery is 40 mA/cm.sup.2.

[0042] The electrode is coated with super P, the load is 12 mg/cm.sup.2 and the pH of the electrolyte is adjusted to 1. The membrane material is composite membrane (PE is the substrate with Nafion resin as coating).

[0043] FIG. 21 shows the cycle performance of zinc manganese battery to the battery assembled comparative Example 4. The electrolyte composition is 0.5 M manganese acetate, 0.5 M zinc acetate, supporting electrolyte is 2 M KCl. The operating current density of the battery is 40 mA/cm.sup.2. The electrode was coated with super P, the loading capacity was 12 mg/cm.sup.2, and the pH of the electrolyte was adjusted to 9. The membrane material is composite membrane (PE is the substrate with Nafion resin as coating).

SPECIFIC EMBODIMENTS

[0044] In order to further illustrate the invention, the following embodiments are enumerated, but the scope of the invention defined in the claims is not limited.

[0045] Embodiment 1-24 are zinc manganese flow batteries assembled by a single battery, and the single battery successively includes a positive end plate, positive current collector, carbon felt positive electrode with frame, membrane, carbon felt negative electrode with frame, negative current collector, negative end plate, electrolyte storage tank and pump with positive and negative electrolyte. Electrolyte flow rate is 10 ml/min, charging current is 40 mA/cm.sup.2, the cut-off condition of the battery is time cut-off, and the charging cut-off time is 10-30 mins, the safe voltage is set to 2.3 V and the discharge voltage is 0.1 v.

[0046] The electrode area is 48 cm.sup.2, the thickness of carbon felt is 5 mm, and the compression ratio is 30%.

TABLE-US-00001 TABLE 1 details of assembling the battery under different conditions of Embodiment. Electrode coating and Substrate Energy Areal Electrolyte load and coating efficiency capacity Embodiment (mol/L) Ac.sup.−:Mn.sup.2+ Mn.sup.2+:Zn.sup.2+ pH (mg/cm.sup.2) layer EE (mAh/cm.sup.2) 1 0.5MMnAc, 4:1 1:1 5 Super P, 12 PE, Nafion 76% 14 0.5MZnAc, The pore 2MKCl diameter of the composite membrane substrate is 10-50 nm and the porosity is 30-60%. 2 1MMnAc, 4:1 1:1 5 Super P, 12 PE, Nafion 75% 21 1MZnAc, 2MKCl 3 1.5MMnAc, 4:1 1:1 5 Super P, 12 PE, Nafion 69% 27 1.5MZnCl.sub.2, 2MKCl 4 0.5MMnCl.sub.2 + 1:1 1:1 5 Super P, 12 PE, Nafion 65% 12 0.5M MnAc, 1MZnCl.sub.2, 2MKCl 5 1MMnAc, 2:1 1:1 5 Super P, 12 PE, Nafion 68% 15 1MZnCl.sub.2, 2MKCl 6 1MMnAc, 3:1 1:1 5 Super P, 12 PE, Nafion 65% 18 1MZnCl.sub.2, 2MKCl + 1MKAc 7 1MMnAc, 5:1 1:1 5 Super P, 12 PE, Nafion 63% 15 1MZnAc, 2MKCl, 1MKAc 8 1MMnAc, 6:1 1:1 5 Super P, 12 PE, Nafion 60% 13 1MZnAc, 2MKCl, 2MKAc 9 1MMnAc, 4:1 2:3 5 Super P, 12 PE, Nafion 69% 18 1MZnAc, 0.5M ZnCl.sub.2, 2MKCl 10 1MMnAc, 4:1 1:2 5 Super P, 12 PES, Nafion 68% 17 1MZnAc, 1M ZnCl.sub.2, 2MKCl 11 1MMnAc, 4:1 1:1 4 Super P, 12 PE, Nafion 65% 18 1MZnAc, 2MKCl 12 1MMnAc, 4:1 1:1 4.5 Super P, 12 PE, Nafion 67% 19 1MZnAc, 2MKCl 13 1MMnAc, 4:1 1:1 5.5 Super P, 12 PE, Nafion 67% 19 1MZnAc, 2MKCl 14 1MMnAc, 4:1 1:1 6 Super P, 12 PE, Nafion 66% 18 1MZnAc, 2MKCl 15 1MMnAc, 4:1 1:1 5 Keqin PE, Nafion 67% 14 1MZnAc, black, 12 2MKCl 16 1MMnAc, 4:1 1:1 5 Carbon PE, Nafion 68% 16 1MZnAc, nanotubes, 2MKCl 12 17 1MMnAc, 4:1 1:1 5 Super P, 4 PE, Nafion 57% 13 1MZnAc, 2MKCl 18 1MMnAc, 4:1 1:1 5 Super P, 8 PE, Nafion 57% 13 1MZnAc, 2MKCl 19 1MMnAc, 4:1 1:1 5 Super P, 16 PE, Nafion 55% 13 1MZnAc, 2MKCl 20 1MMnAc, 4:1 1:1 5 Super P, 20 PE, Nafion 54% 7 1MZnAc, 2MKCl 21 1MMnAc, 4:1 1:1 5 Super P, 12 PES, Nafion 64% 14 1MZnAc, 2MKCl 22 1MMnAc, 4:1 1:1 5 Super P, 12 PVC, Nafion 56% 13 1MZnAc, 2MKCl 23 1MMnAc, 4:1 1:1 5 Super P, 12 PE, PBI 68% 15 1MZnAc, 2MKCl 24 1MMnAc, 4:1 1:1 5 Super P, 12 PE, SPEEK 62% 15 1MZnAc, 2MKCl

[0047] FIG. 3 (Embodiment 2) is the optimal condition (the ratio of acetate anion to manganese ion is 4:1, the concentrations of zinc ion and manganese ion are 1 M) battery cycle performance and capacity retention diagram, compared with FIG. 2 (Embodiment 1-0.5 mmnac, 0.5 mznac), the areal capacity of the high concentration electrolyte is greatly improved, and the energy efficiency of the battery is also relatively high. However, FIG. 4 (Embodiment 3-1.5 m MnAc, 1.5 m ZnAc) is close to the saturation concentration, the high concentration causes the viscosity of the electrolyte to be too high, and the energy efficiency of the battery decreases slightly, but the energy density of the battery is the highest.

[0048] Based on embodiment 2, it can be seen from other embodiments. Adjust the concentration ratio of acetate to manganese ion. When the ratio of acetate to manganese ion is low, FIG. 5 (Embodiment 4, the ratio of acetate to manganese ion is 1:1), acetate has a certain coordination effect on manganese ion, but it is not incomplete, so there is still a small amount of manganese ions that can't completely generate MnO.sub.2, and some will generate Mn.sup.3+, which cause disproportion side reaction and the corresponding efficiency and surface capacity are slightly lower. However, when the concentration of acetate reaches a high level, FIG. 6 (embodiment 8, the ratio of acetate to manganese ion is 6:1), excessive acetate coordination will limit the kinetic of the positive electrode. Therefore, the battery efficiency and areal capacity are inhibited. Therefore, the ratio of acetate to manganese ion is preferably 4:1.

[0049] Adjusting the concentration ratio of manganese ion and zinc ion (FIG. 7 (embodiment 9) and FIG. 8 (embodiment 10)), by increasing zinc ion content enables the concentration ratio reach 2:3 or 1:2, the concentration of the electrolyte is close to saturation, which limited the migration rate of ion, thus, the efficiency of the battery decreases obviously, and the excess zinc ion has no effect on the capacity of the battery. The ratio of manganese ion to zinc ion is preferably 1:1.

[0050] By adjusting the pH value of the electrolyte to 4 (embodiment 11) (FIG. 9), 4.5 (embodiment 12) and 5 (embodiment 13), 5.5 (Embodiment 14) (FIG. 10), the coordination effect of acetate ion and manganese ion in electrolyte is slightly weakened, and the manganese ion in the electrolyte may intend to form Mn.sup.3+. The efficiency and areal capacity of the battery decreased slightly. Replacing the coated super P with Keqin black, FIG. 11 (embodiment 15), because of the binding force between the latter and carbon fiber is weaker, which is not conducive to the deposition of MnO2 on the surface of carbon fiber, so the areal capacity of the battery decreases. Reducing the loading capacity of super p in FIG. 12 (Embodiment 17), the roughness of the electrode surface decreases seriously, and the corresponding deposition areal capacity of the crystallinity of manganese dioxide decreased seriously, so the energy efficiency of the battery also decreased significantly. Increase the content of super p to 20 mg/cm.sup.2 (FIG. 13 (Embodiment 20)), because the content of super P is too high, the porosity of carbon felt electrode will be greatly reduced, the deposition space of manganese dioxide is reduced, so the areal capacity of the battery decreases seriously, and the efficiency of the battery also decreases. It is preferred that the electrode coating is super P and the loading is 12 mg/cm.sup.2.

[0051] Replacing the substrate of membrane with PES FIG. 14 (embodiment 21), the efficiency and areal capacity of the battery are reduced. This is mainly because the PES substrate is not conducive to the conduction of neutral ions, the polarization of the battery is serious, and the corresponding energy efficiency is reduced.

[0052] Similar to FIG. 14, FIG. 15 (embodiment 24) after replacing the coating layer with speek also makes it difficult to conduct the supporting electrolyte in the battery, and the performance of the battery decreases seriously. It is preferred that the substrate is PE and the coating is Nafion.

[0053] Embodiments 25-27 are zinc manganese batteries assembled by a single battery, wherein the structure of zinc manganese batteries successively includes positive electrode, negative electrode, diaphragm, positive electrolyte and negative electrolyte; Battery performance test: the flow rate of electrolyte is 10 ml/min, the charging current is 40 mA/cm.sup.2, the cut-off condition of battery is time cut-off: the charging cut-off time is 10-30 mins, the safety voltage is set to 2.3V, and the discharge voltage is 0.1V. The electrode area is 48 cm.sup.2, the thickness of carbon felt is 5 mm, and the compression ratio is 30%.

[0054] FIG. 16 (battery embodiment 26) shows the performance of the battery under the optimal conditions, which can obtain relatively high energy efficiency and areal capacity.

[0055] For the zinc manganese flow battery assembled with single battery in comparative Example 1-5, the single battery successively includes positive end plate, positive current collector, carbon felt positive electrode with liquid flow frame, membrane, carbon felt negative electrode with liquid flow frame, negative current collector, negative end plate, electrolytic solution storage tank and pump equipped with positive and negative electrolyte. The electrolyte flow rate is 10 ml/min, the charging current is 40 mA/cm.sup.2, and the cut-off condition of the battery is time cut-off: the charging cut-off time is 10-30 mins, the safety voltage is set to 2.3 V, and the discharge voltage is 0.1 V. The electrode area is 48 cm.sup.2, the thickness of carbon felt is 5 mm, and the compression ratio is 30%.

[0056] When the acetate ion in the positive electrolyte is completely removed, a large amount of Mn.sup.3+ will be generated in the positive electrode of the battery, and with serious disproportionation side reactions, the areal capacity and efficiency of the battery will be seriously reduced (Comparative Example 1, FIG. 17). In addition, if the coating layer on the membrane electrode is removed, the acetate generated during the electrochemical reaction of the positive electrode will cross the membrane and corrode the deposited zinc, resulting in the decrease of the coulomb efficiency of the battery and greatly reduced stability of the battery (Comparative Example 2, FIG. 18). When the coating layer on the positive electrode is removed, due to the smooth surface of the carbon fiber, the contact force between the manganese dioxide generated on the positive electrode and the substrate is relatively weak, and the crystallinity is also relatively poor, which will cause the precipitation fall off, so the surface capacity and efficiency of the battery will be reduced (Comparative Example 3, FIG. 19). Reduce the pH of the positive electrolyte to strong acidity, and the acetate radical in the positive electrolyte will form acetic acid with H.sup.+ instead of coordinating with Mn.sup.2+, therefore, a large amount of Mn.sup.3+ will be generated during the charging process of the positive electrode, accompanied by obvious disproportionation side reactions, so the areal capacity and efficiency of the battery are very low (Comparative Example 4, FIG. 20). When the pH of the positive electrolyte is increased to strong alkalinity, manganese ions will form hydroxide precipitation, so the battery performance is very poor. (Comparative Example 5, FIG. 21).

TABLE-US-00002 Electrode coating and Substrate Energy Areal Electrolyte load and coating efficiency capacity Embodiment (mol/L) Ac.sup.−:Mn.sup.2+ Mn.sup.2+:Zn.sup.2+ pH (mg/cm.sup.2) layer EE (mAh/cm.sup.2) 25 0.5MMnAc, 4:1 1:1 5 Super P, 12 PE, Nafion 76% 10 0.5MZnAc, 2MKCl 26 1MMnAc, 4:1 1:1 5 Super P, 12 PE, Nafion 76% 16 1MZnAc, 2MKCl 27 1MMnAc, 4:1 1:1 5 Super P, 12 PE, Nafion 68% 21 1MZnAc, 2MKCl

TABLE-US-00003 TABLE 2 Comparative example of assembled battery. Electrode coating Substrate Areal Comparative Electrolyte and load layer and Capacity Example (mol/L) Ac.sup.−:Mn.sup.2+ Mn.sup.2+:Zn.sup.2+ pH (mg/cm.sup.2) coating EE (mAh/cm.sup.2) 1 0.5M MnSO.sub.4, 0:1 1:1 5 Super P, 12 PE, Nafion 52% 5 0.5M ZnSO4, 0.5M K.sub.2SO.sub.4 2 0.5MMnAc, 4:1 1:1 5 None PE, Nafion 60% 8 0.5MZnAc, 2MKCl 3 0.5MMnAc, 4:1 1:1 5 Super P, 12 PE, No 62% 8 0.5MZnAc, 2MKCl 4 0.5MMnAc, 4:1 1:1 1 Super P, 12 PE, Nafion 52% 7 0.5MZnAc, 2MKCl 5 0.5MMnAc, 4:1 1:1 9 Super P, 12 PE, Nafion 53% 6 0.5MZnAc, 2MKCl

[0057] The neutral zinc manganese battery of the invention comprises a neutral zinc manganese flow battery and a power battery. The battery structure mainly includes: positive electrode, negative electrode, electrolyte and diaphragm. The corresponding flow battery also includes positive and negative pumps, pipelines and electrolyte storage tanks. For the two structures of flow battery and battery, the positive and negative materials are porous carbon felt and the membrane material is polymer material. For the power battery, the electrolyte is stored in the porous electrode, while for the flow battery, the positive and negative electrolyte flows through the positive and negative electrodes through the pump and pipeline and finally returns to the storage tank to realize the circulation of electrolyte in the electrode chamber and storage tank. In addition, the positive and negative electrode electrolyte is a neutral solution of zinc salt and manganese salt with specific composition, which is not corrosive to the electrode and collector. During charging, Mn.sup.2+ of the positive electrode can be oxidized directly to α-MnO.sub.2 and MnO.sub.2 dissolves into Mn.sup.2+ during discharge. Different from the intercalation/deintercalation mechanism of traditional zinc manganese secondary battery, this dissolution deposition method can avoid the collapse of material structure in the cycle process, and the cycle life of the battery is greatly prolonged. In addition, the reaction is double electron transfer, which greatly improves the energy density of the battery.