Organic zinc air battery with long cycle life and high stability

Abstract

The invention discloses an organic zinc air battery with long cycle life and high stability, and belongs to the technical field of batteries. The organic zinc-air battery consists of a positive electrode, a negative electrode and electrolyte, the positive electrode is composed of a conductive current collector, a conductive agent and a binder, the negative electrode is metal zinc, the electrolyte is composed of an organic solvent and organic and inorganic zinc salt solutes, and the concentration of zinc ions in the electrolyte is 0.1-4 mol / L. Compared with the prior art, the organic zinc air battery disclosed by the invention has the following advantages that the organic solution is adopted as the solvent, the electrolyte volatilization phenomenon in an open system is reduced, the problems of hydrogen evolution side reaction and the like of the electrolyte in the charge-discharge process are solved, stable discharge and charge cycle operation in the air can be realized, and the service life of the battery is prolonged. An organic zinc air secondary battery having a long service life is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of batteries and relates to an organic zinc-air battery. Background Art

[0002] Faced with the increasing scarcity of fossil fuel resources and the two major challenges of climate change and environmental pollution caused by traditional energy utilization, it is imperative to develop sustainable rechargeable batteries to store renewable energy. Zinc-air batteries are usually composed of zinc metal negative electrodes, electrolytes and air positive electrodes. They have a high theoretical energy density (1353Wh / kg) and are therefore regarded as a battery technology with broad development prospects.

[0003] Traditional air-zinc batteries usually use aqueous alkaline electrolytes (such as 6 mol / kg KOH solution), which have the advantages of low viscosity, high conductivity, and low cost, making the battery show excellent performance. However, alkaline electrolytes also bring a series of problems, such as severe dendrites of zinc negative electrode, hydrogen corrosion, corrosion of positive electrode carbon carrier, and electrolyte deterioration caused by carbon dioxide (CO2). In addition, in alkaline electrolytes, inert discharge products may lead to slow reaction kinetics of the charging process, resulting in a higher charging voltage. These problems limit the development and commercial application of rechargeable secondary zinc-air batteries.

[0004] As mentioned above, common aqueous electrolytes have problems such as volatility, negative electrode hydrogen evolution corrosion, carbon positive electrode corrosion, and electrolyte deterioration. Developing new zinc-air battery electrolytes is an effective means to solve this problem. Organic electrolytes can not only effectively alleviate the electrolyte volatilization problem caused by aqueous electrolytes in the open structure of zinc-air batteries, but also solve the problem of hydrogen evolution side reactions during the charge and discharge process of aqueous electrolytes, and can realize long-life organic zinc-air secondary batteries. Summary of the invention

[0005] In view of the problems existing in the aqueous electrolyte of zinc-air batteries, the present invention aims to provide an organic zinc-air battery with a long cycle life, which has the characteristics of good cyclability, long calendar life, and environmental friendliness.

[0006] The technical solution of the present invention is an organic zinc-air battery with long cycle life and high stability. The air battery is composed of a positive electrode, a negative electrode and an electrolyte. The positive electrode includes: a conductive current collector, a conductive agent and a binder. The binder bonds the conductive current collector and the conductive agent, and the conductive agent is located between the electrolyte and the conductive current collector.

[0007] The solvent of the electrolyte is one or more of sulfone compounds, amide compounds, ether compounds, and ester compounds; the solute of the electrolyte is an organic zinc salt or an inorganic zinc salt;

[0008] During the discharge process, Zn loses electrons and becomes Zn 2+ , migrates to the positive electrode under the action of the electric field, and O2 loses electrons at the positive electrode and becomes O 2- , the discharge product ZnO is generated at the positive electrode; during the charging process, the discharge product ZnO at the positive electrode decomposes to generate O2 and Zn 2+ , Zn at the negative electrode 2+ It gains electrons and becomes Zn, which is deposited at the metallic zinc negative electrode.

[0009] The conductive current collector is one of hydrophobic carbon paper, hydrophobic carbon cloth, and nickel foam;

[0010] The conductive agent is one of carbon nanotubes, conductive carbon black, graphene, activated carbon, acetylene black, and Ketjen black;

[0011] The binder is one of polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyacrylic acid (PAA), and polyvinyl alcohol (PVA);

[0012] The negative electrode is one of metal zinc foil, metal zinc sheet and metal zinc powder. When the zinc powder is used as an electrode, it is obtained by pressing the metal zinc powder and a binder. The binder is one of PTFE, sodium carboxymethyl cellulose (CMC) and PVDF.

[0013] The inorganic zinc salt is one or more of Zn[N(CF3SO2)2]2, Zn(CF3SO3)2, Zn(CH3CO2)2, ZnSO4, ZnCl2, Zn(ClO3)2, Zn(NO3)2, and ZnBF4.

[0014] The concentration of zinc ions in the electrolyte is 0.1-4 mol / L.

[0015] The sulfone compounds include: dimethyl sulfoxide (DMSO), trifluoromethyl ethyl sulfone (FMES), trifluoromethyl propyl sulfone (FMPS), and cyclopentane (TMS);

[0016] The amide compounds include: N,N-dimethylformamide (DMF), dimethylacetamide (DMAC), N-methylformamide (NMF), diethylformamide (DEF);

[0017] The ether compounds include: ethylene glycol dimethyl ether (DME), diethylene glycol dimethyl ether (DEGDME), tetraethylene glycol dimethyl ether (TEGDME);

[0018] The ester compounds include: dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), ethylene carbonate (EC), and propylene carbonate (PC).

[0019] N,N-dimethylformamide is used as solvent and Zn[N(CF3SO2)2]2 is used as solute.

[0020] Dimethyl sulfoxide is used as solvent and Zn(CF3SO3)2 is used as solute.

[0021] Dimethyl sulfoxide is used as solvent and Zn[N(CF3SO2)2]2 is used as solute.

[0022] The working mechanism of the organic zinc-air battery described in the present invention is: during the discharge process, Zn loses electrons and becomes Zn 2+ , migrates to the positive electrode under the action of the electric field, and O2 loses electrons at the positive electrode and becomes O 2- , generating discharge product ZnO at the positive electrode. During the charging process, the discharge product ZnO at the positive electrode decomposes to generate O2 and Zn 2+ , Zn at the negative electrode 2+ It gains electrons and becomes Zn, which is deposited at the metallic zinc negative electrode.

[0023] The advantages provided by the present invention are as follows:

[0024] (1) The organic electrolyte in the organic zinc-air battery provided in the present invention does not react with CO2 in the air, can operate stably in the air, and will not cause a decrease in conductivity due to electrolyte deterioration.

[0025] (2) The organic solvent provided in the present invention has a saturated vapor pressure greater than that of water, thereby reducing the solvent evaporation phenomenon in the open system of the air battery.

[0026] (3) The aprotic organic solvent provided in the present invention inhibits the corrosion, hydrogen evolution, dendrite growth and other phenomena of the zinc negative electrode, and greatly improves the electrochemical reversibility of the zinc negative electrode.

[0027] (4) The organic zinc-air battery provided in the present invention has good electrochemical reversibility and a long cycle life. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is the XRD diagram of the discharge product of the organic zinc-air battery in Example 1.

[0029] Figure 2 This is the XRD diagram of the discharge product of the organic zinc-air battery in Example 2.

[0030] Figure 3 This is the XRD diagram of the discharge product of the organic zinc-air battery in Example 3.

[0031] Figure 4 This is the XRD diagram of the discharge product of the organic zinc-air battery in Example 4.

[0032] Figure 5 This is the XRD diagram of the discharge product of the organic zinc-air battery in Example 5.

[0033] Figure 6 This is the XRD diagram of the discharge product of the organic zinc-air battery in Example 6.

[0034] Figure 7 This is the charge and discharge cycle performance diagram of the organic zinc-air battery in Example 7.

[0035] Figure 8 This is a charge and discharge cycle performance diagram of the organic zinc-air battery in Example 8.

[0036] Fig. 9 This is a charge and discharge cycle performance diagram of the organic zinc-air battery in Example 9.

[0037] Fig.10 This is a charge and discharge cycle performance diagram of the organic zinc-air battery in Example 10.

[0038] Fig.11 Schematic diagram of the structure of the organic zinc-air battery according to the present invention. DETAILED DESCRIPTION

[0039] The present invention proposes to use common organic compounds such as sulfone compounds, amide compounds, ether compounds, ester compounds, etc. as solvents for zinc-air battery electrolytes, and one or more of organic zinc salts and inorganic zinc salts, bis(trifluoromethylsulfonylimide) zinc (Zn[N(CF3SO2)2]2), zinc trifluoromethanesulfonate (Zn(CF3SO3)2), zinc acetate (Zn(CH3CO2)2), zinc sulfate (ZnSO4), zinc chloride (ZnCl2), zinc perchlorate (Zn(ClO3)2), zinc nitrate (Zn(NO3)2), zinc tetrafluoroborate (ZnBF4), etc. as solutes to assemble an organic zinc-air secondary battery.

[0040] The present invention is described in detail below in conjunction with the embodiments, but the protection scope of the present invention is not limited to the following embodiments.

[0041] Example 1: Discharge product test of organic zinc-air battery

[0042] Using DMF as solvent, Zn[N(CF3SO2)2]2 was dissolved in DMF at a concentration of 1 mol / L. The preparation of the positive electrode sheet is as follows: using carbon nanotubes as a conductive agent, PTFE as a binder, and hydrophobic carbon paper as a current collector, the conductive agent and the binder are uniformly mixed at a mass ratio of conductive agent (carbon nanotubes): binder (PTFE) = 9:1, and the mixture is coated on the current collector to obtain a positive electrode sheet loaded with a conductive layer. In this embodiment, the conductive agent loading amount of the positive electrode is 15 mg / cm 2. Metal zinc foil was used as the negative electrode material with a thickness of 50 μm. Glass fiber membrane was used as the separator to assemble the organic zinc-air battery. The assembled battery was subjected to discharge test at 25°C. The current density was 0.1 mA / cm 2 , the discharge time is 10 hours. Figure 1 It can be seen that in this organic electrolyte system, ZnO is formed on the positive electrode surface after discharge.

[0043] Example 2: The difference between this example and Example 1 is that Zn[N(CF3SO2)2]2 is dissolved in DMF at a concentration of 0.5 mol / L, and the positive electrode sheet, negative electrode material and separator used are the same as those in Example 1. The assembled battery is subjected to a discharge test at 25°C. Current density 0.1 mA / cm 2 , the discharge time is 10 hours. Figure 2 It can be seen that in this organic electrolyte system, ZnO is also formed on the positive electrode surface after discharge. Example 2 shows that after changing the zinc ion concentration in the electrolyte, the discharge product in the organic zinc-air battery is still ZnO.

[0044] Example 3: The difference between this example and Example 1 is that DMSO is used as solvent, Zn(CF3SO3)2 is dissolved in DMSO at a concentration of 0.2 mol / L, and the positive electrode sheet, negative electrode material and separator used are the same as those in Example 1. The assembled battery is subjected to a discharge test at 25°C. Current density 0.1 mA / cm 2 , the discharge time is 10 hours. Figure 3 It can be seen that in this organic electrolyte system, ZnO is also formed on the positive electrode surface after discharge. Example 3 shows that after replacing the solute zinc salt, the discharge product in the organic zinc-air battery is still ZnO.

[0045] Example 4: The difference between this example and Example 1 is that Zn[N(CF3SO2)2]2 is dissolved in DMSO at a concentration of 1 mol / L, and the assembled battery is subjected to a discharge test at 25°C. Current density 0.1 mA / cm 2 , the discharge time is 10 hours. Figure 4 It can be seen that in this organic electrolyte system, ZnO is also formed on the positive electrode surface after discharge. Example 4 shows that after changing the electrolyte composition, the discharge product in the organic zinc-air battery is still ZnO.

[0046] Example 5: The difference between this example and Example 1 is that Zn(CH3CO2)2 is dissolved in DMSO at a concentration of 1 mol / L, and the assembled battery is subjected to a discharge test at 25°C. Current density 0.1 mA / cm 2 , the discharge time is 10 hours. Figure 5It can be seen that in this organic electrolyte system, ZnO is also formed on the positive electrode surface after discharge. Example 5 shows that after changing the electrolyte composition, the discharge product in the organic zinc-air battery is still ZnO.

[0047] Example 6: The difference between this example and example 1 is that the discharge current density used is 0.2 mA / cm 2 , the discharge time is 10 hours. The discharge products of organic zinc-air batteries are as follows Figure 6 As shown in Example 6, the organic zinc-air battery still has the same discharge product at a higher current density as that at a low current density, indicating that the organic zinc-air battery has stable electrochemical properties.

[0048] Example 7: Long cycle test of organic zinc-air battery

[0049] The difference between this embodiment and embodiment 1 is that the test procedure is changed to a test current density of 0.1 mA / cm 2 , the discharge and charge time is 10 hours. Figure 7 As shown, the prepared organic electrolyte-based zinc-air battery can stably discharge and charge in air for 400 hours.

[0050] Example 8: The difference between this example and example 7 is that the test current density is 0.2 mA / cm 2 , the discharge and charge time is 10 hours. Figure 8 As shown, the prepared zinc-air battery based on organic electrolyte can stably discharge and charge in air for 100 hours. Organic zinc-air battery can discharge and charge for a long time at a higher current density.

[0051] Example 9: The difference between this example and Example 7 is that the electrolyte composition uses DMSO as the solvent, and Zn[N(CF3SO2)2]2 is dissolved in DMSO at a concentration of 1 mol / L to perform a discharge and charge cycle test. Fig. 9 As shown, the prepared organic zinc-air battery can stably cycle for 150 hours. The organic zinc-air battery can stably cycle in a variety of organic solvents, which broadens the selection range of organic solvents and has a higher application range and application value.

[0052] Example 10: The difference between this example and Example 9 is that the solute zinc salt is replaced with Zn(CF3SO3)2, which is dissolved in DMSO at a concentration of 0.2 mol / L, and the discharge-charge cycle test is performed. Fig.10 As shown, the prepared organic zinc-air battery can stably cycle for 90 hours. Organic zinc-air batteries can stably cycle under a variety of zinc salts, which broadens the selection range of solute zinc salts and has a higher application range and application value.

Claims

1. An organic zinc-air battery with long cycle life and high stability, the air battery is composed of a positive electrode, a negative electrode, and an electrolyte; the positive electrode comprises: Conductive current collector, conductive agent, binder; the binder bonds the conductive current collector and the conductive agent, and the conductive agent is located between the electrolyte and the conductive current collector; The solvent of the electrolyte is one or more of sulfone compounds, amide compounds, ether compounds, and ester compounds; the solute of the electrolyte is an organic zinc salt or an inorganic zinc salt; During the discharge process, Zn loses electrons and becomes Zn 2+ , migrates to the positive electrode under the action of the electric field, and O2 loses electrons at the positive electrode and becomes O 2- , the discharge product ZnO is generated at the positive electrode; during the charging process, the discharge product ZnO at the positive electrode decomposes to generate O2 and Zn 2+ , Zn at the negative electrode 2+ It gains electrons and becomes Zn, which is deposited at the metallic zinc negative electrode.

2. An organic zinc-air battery with long cycle life and high stability as claimed in claim 1, characterized in that: The conductive current collector is one of hydrophobic carbon paper, hydrophobic carbon cloth, and nickel foam; the conductive agent is one of carbon nanotubes, conductive carbon black, graphene, activated carbon, acetylene black, and Ketjen black; the binder is one of polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyacrylic acid (PAA), and polyvinyl alcohol (PVA).

3. An organic zinc-air battery with long cycle life and high stability as claimed in claim 1, characterized in that: The negative electrode is one of metal zinc foil, metal zinc sheet and metal zinc powder. When the zinc powder is used as an electrode, it is obtained by pressing the metal zinc powder and a binder. The binder is one of PTFE, sodium carboxymethyl cellulose (CMC) and PVDF.

4. An organic zinc-air battery with long cycle life and high stability as claimed in claim 1, characterized in that: The inorganic zinc salt is one or more of Zn[N(CF3SO2)2]2, Zn(CF3SO3)2, Zn(CH3CO2)2, ZnSO4, ZnCl2, Zn(ClO3)2, Zn(NO3)2, and ZnBF4.

5. The organic zinc-air battery with long cycle life and high stability as claimed in claim 1, characterized in that: The concentration of zinc ions in the electrolyte is 0.1-4 mol / L.

6. The organic zinc-air battery with long cycle life and high stability as claimed in claim 1, characterized in that: The sulfone compounds include: dimethyl sulfoxide (DMSO), trifluoromethyl ethyl sulfone (FMES), trifluoromethyl propyl sulfone (FMPS), and cyclopentane (TMS).

7. An organic zinc-air battery with long cycle life and high stability as claimed in claim 1, characterized in that: The amide compounds include: N,N-dimethylformamide (DMF), dimethylacetamide (DMAC), N-methylformamide (NMF), diethylformamide (DEF); The ether compounds include: ethylene glycol dimethyl ether (DME), diethylene glycol dimethyl ether (DEGDME), tetraethylene glycol dimethyl ether (TEGDME); The ester compounds include: dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), ethylene carbonate (EC), and propylene carbonate (PC).

8. An organic zinc-air battery with long cycle life and high stability as claimed in claim 1, characterized in that: N,N-dimethylformamide is used as solvent and Zn[N(CF3SO2)2]2 is used as solute.

9. An organic zinc-air battery with long cycle life and high stability as claimed in claim 1, characterized in that: Dimethyl sulfoxide is used as solvent and Zn(CF3SO3)2 is used as solute.

10. An organic zinc-air battery with long cycle life and high stability as claimed in claim 1, characterized in that: Dimethyl sulfoxide is used as solvent and Zn[N(CF3SO2)2]2 is used as solute.

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