Zinc ion electrolyte and battery

Abstract

This invention discloses a zinc-ion electrolyte and a battery, belonging to the field of battery technology. The electrolyte in the electrolyte is selected from ZnCl₂O₈ and ZnF₂. 12 The electrolyte is selected from one of P2 and Zn(TFSI)2, and the solvent is selected from one or more of DMC, PC, EMC, DEC, and EC. This invention also provides a zinc-ion battery containing the above-mentioned electrolyte. The battery prepared using this invention has a higher operating voltage, solves the hydrogen evolution problem caused by the presence of water during charging and discharging, and also improves battery life.

Description

Technical Field

[0001] The invention belongs to the technical field of batteries, and in particular relates to a zinc ion electrolyte and a battery. Background Art

[0002] Zinc-ion batteries are secondary zinc-based batteries. Zinc-ion batteries are usually based on α-MnO with a large tunnel 2 As the positive electrode, metal zinc is the negative electrode, containing Zn 2+ The neutral aqueous solution is the electrolyte. In zinc ion batteries, Zn 2+ It can be rapidly and reversibly deposited and dissolved on the surface of the metal zinc anode, and can also be deposited on the surface of α-MnO 2 Reversible insertion or extraction in the tunnel. In the battery reaction, the positive electrode material α-MnO 2 The structure changes to a spinel-like trivalent manganese phase (ZnMn 2 O 4 ), layered divalent manganese phase (Zn x MnO 2 ) and tunnel-type divalent manganese phase (Zn x MnO 2 ). After the discharge is complete, these three manganese phases coexist. It can be seen that the essence of zinc ion battery is Mn 4+ , Mn 3+ and Mn 2+ The mutual conversion process realizes the transformation of chemical energy and electrical energy.

[0003] Conventional zinc-ion batteries use aqueous solution with ZnSO 4 As electrolyte, the zinc electrode will directly generate insoluble ZnO or Zn(OH) due to discharge. 2 The anode products cover the electrode surface, affecting the normal dissolution of zinc, reducing the reaction surface area of ​​the zinc electrode, and causing the electrode to lose activity and become "passive", so there are great limitations. Summary of the invention

[0004] In order to solve at least one of the above technical problems, the present invention adopts the following technical solutions:

[0005] The first aspect of the present invention provides a zinc ion electrolyte, wherein the electrolyte of the electrolyte is selected from ZnCl 2 O 8 、ZnF 12 P 2 、Zn(TFSI) 2 The solvent of the electrolyte is selected from one of DMC, PC, EMC, DEC and EC.

[0006] In some embodiments of the present invention, the solvent is selected from two or more of DMC, PC, EMC, DEC and EC, and further, the volume ratio of any one solvent is 2% to 98%.

[0007] In some embodiments of the present invention, the concentration of the electrolyte is 0.5-10 mol / L.

[0008] Furthermore, the electrolyte also includes an additive, and the additive is selected from one or more of Vc, PS, ES, and FEC.

[0009] In some embodiments of the present invention, the additive is selected from two or more of Vc, PS, ES, and FEC. Further, the volume ratio of any one of the additives is 0.1% to 50%.

[0010] The second aspect of the present invention provides a zinc ion battery, which is composed of the electrolyte, positive electrode sheet, negative electrode sheet and separator described in any one of the first aspects of the present invention.

[0011] Furthermore, the positive electrode sheet is prepared by coating the active material of the positive electrode sheet on the current collector of the positive electrode sheet, and the negative electrode sheet is prepared by coating the active material of the negative electrode sheet on the current collector of the negative electrode sheet. Preferably, the current collector used to prepare the positive electrode sheet is the same as the current collector used to prepare the negative electrode sheet.

[0012] In some embodiments of the present invention, the current collector is a stainless steel mesh.

[0013] In other embodiments of the present invention, the current collector is made of one or more metals selected from the group consisting of aluminum, nickel, titanium, copper, iron, aluminum, zinc and chromium.

[0014] In some other embodiments of the present invention, the current collector is a metal coating or an inorganic coating coated on an organic film. Wherein, the organic film is selected from one of PET, PP, PE, PI, PVC and OPP, and may be a porous film or a non-porous film. The present invention does not impose any restrictions, and its shape and pattern are also not subject to any restrictions. Optionally, the metal coating is prepared from one or more metals of Al, Ni, Ti, Cu, Fe, Al, Zn and Cr. For example, the organic film selects PET, and Al is coated on both sides of the organic film to obtain the current collector Al / PET / Al; for another example, the organic film selects PET, and Ni is coated on both sides of the organic film to obtain the current collector Ni / PET / Ni; for another example, the organic film selects PET, and Ni is coated on both sides of the organic film, and then Cu is coated on both sides to obtain the current collector Cu / Ni / PET / Ni / Cu. For another example, the organic film selects PET, and Ti is coated on both sides of the organic film, and then Al or Cu is coated on both sides to obtain the current collector Al / Ti / PET / Ti / Al or Cu / Ti / PET / Ti / Cu. Optionally, the inorganic coating is made of Al 2 O 3 、TiO 2 、SiO 2 or Cr 2 O 3 Preferably, the outer surface of the current collector is also coated with a conductive coating, and the conductive coating is made of carbon C, CNT, carbon black or graphite.

[0015] In the present invention, the active material of the positive electrode sheet includes anhydrous Mn 3 O 4 , conductive agent and binder; the active material of the negative electrode sheet includes Zn metal, conductive agent and binder.

[0016] Conductive agent is a key auxiliary material of the battery. In some embodiments of the present invention, the conductive agent is selected from metal conductive agents (silver powder, copper powder, nickel powder, etc.), metal oxide conductive agents (tin oxide, iron oxide, zinc oxide, etc.), carbon conductive agents (carbon black, graphite, etc.), fibrous conductive agents (carbon fiber, carbon nanotubes, etc.).

[0017] Binder is one of the important components of battery pole sheets. It is a polymer compound that adheres the active material and conductive agent in the electrode sheet to the electrode current collector. It has the function of enhancing the contact between the active material, conductive agent and current collector and stabilizing the pole sheet structure. It is an additional material with high technical content in battery materials. In some embodiments of the present invention, the binder is selected from one of PVDF, CMC / SBR, PTFE, DMA and acrylic glue.

[0018] In some embodiments of the present invention, the active material of the positive electrode sheet includes anhydrous Mn 3O 4 , the ratio of conductive agent to binder is (70~98):(1~15):(1~15), for example 95:2:3.

[0019] In some embodiments of the present invention, the ratio of Zn metal, conductive agent and binder in the active material of the negative electrode sheet is (70-98): (1-15): (1-15), for example, 95:2:3. In some specific embodiments of the present invention, the Zn metal is Zn metal foil, Zn metal powder or Zn metal particles. Further, the Zn metal includes a coating layer on the outside, for example, the coating layer is ZnCl 2 、ZnF 2 、Al 2 O 3 、TiO 2 Thus, the coating layer coats the Zn metal to form the first particles, the first particles are mixed with the conductive agent and the binder to form the second particles, and the second particles are coated on the current collector to prepare the negative electrode sheet.

[0020] Furthermore, the negative electrode sheet is coated with a protective layer. In some embodiments of the present invention, the protective layer is made of organic matter, wherein the organic matter is selected from one or more of PMMA, PVDF and CMC / SBR. Preferably, the protective layer is PMMA. In other embodiments of the present invention, the protective layer is a composite of organic and inorganic matter, wherein the inorganic matter is selected from Al 2 O 3 , boehmite, SiO 2 、TiO 2 One or more of the above, optionally, the protective layer is made of PMMA and Al 2 O 3 Optionally, the protective layer is composed of PVDF and Al 2 O 3 Composition; Optionally, the protective layer consists of PVDF and boehmite.

[0021] The diaphragm refers to a layer of diaphragm material between the positive and negative electrodes of the battery. It is a very critical part of the battery and has a direct impact on the safety and cost of the battery. Its main functions are to isolate the positive and negative electrodes and prevent the electrons in the battery from passing freely, while allowing the ions in the electrolyte to pass freely between the positive and negative electrodes. In some embodiments of the present invention, the diaphragm is composed of a porous material. In some embodiments of the present invention, the diaphragm is a substrate composed of PP, PE, PVDF, paper, non-woven fabric or one or more composite materials. Furthermore, the surface of the substrate is coated with an inorganic material such as Al 2 O 3 , boehmite, SiO 2、TiO 2 , or multi-layer composite Al 2 O 3 , PVDF, PTEF and other complexes.

[0022] Furthermore, the positive electrode sheet, the separator and the negative electrode sheet are sequentially stacked together and placed in an electrolyte. In some embodiments of the present invention, the structure of the battery is selected from a cylindrical, a rectangular parallelepiped, and a cubic shape, wherein the positive electrode sheet, the separator and the negative electrode sheet are stacked together and then wound into a cylinder to prepare a cylindrical battery.

[0023] In some embodiments of the present invention, the battery is a soft-pack battery or a bipolar battery. In some embodiments of the present invention, the preparation method of the soft-pack battery or the bipolar battery is a conventional preparation method in the art.

[0024] Beneficial effects of the present invention

[0025] Compared with the prior art, the present invention has the following beneficial effects: it has a higher operating voltage, solves the problem of hydrogen evolution caused by the presence of water during the charging and discharging process, and also improves the life of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A partial schematic diagram of the preparation method of the zinc ion battery of Example 3 of the present invention is shown.

[0027] Figure 2 The performance test results of the zinc ion battery prepared in Example 3 in Example 4 of the present invention are shown. DETAILED DESCRIPTION

[0028] Unless otherwise indicated, implied from the context, or customary in the prior art, all parts and percentages in this application are based on weight, and the test and characterization methods used are all current as of the filing date of this application. Where applicable, the contents of any patent, patent application or publication referred to in this application are fully incorporated herein by reference, and their equivalent patent families are also incorporated by reference, especially the definitions of synthesis techniques, product and processing designs, polymers, comonomers, initiators or catalysts disclosed in these documents in the art. If the definition of a specific term disclosed in the prior art is inconsistent with any definition provided in this application, the definition of the term provided in this application shall prevail.

[0029] The numerical ranges in this application are approximate values, so unless otherwise specified, they may include values ​​outside the range. Numerical ranges include all values ​​from the lower limit to the upper limit increased by 1 unit, provided that there is an interval of at least 2 units between any lower value and any higher value. For example, if the recorded component, physical or other properties (such as molecular weight, melt index, etc.) are 100 to 1000, it means that all single values ​​are clearly listed, such as 100, 101, 102, etc., and all sub-ranges, such as 100 to 166, 155 to 170, 198 to 200, etc. For a range containing a value less than 1 or containing a fraction greater than 1 (such as 1.1, 1.5, etc.), 1 unit is appropriately regarded as 0.0001, 0.001, 0.01 or 0.1. For a range containing a single digit less than 10 (such as 1 to 5), 1 unit is usually regarded as 0.1. These are only specific examples of what is intended, and all possible combinations of numerical values ​​between the lowest value and the highest value enumerated are to be considered to be expressly stated in this application.

[0030] When used with respect to chemical compounds, unless expressly specified otherwise, the singular includes all isomeric forms and vice versa (e.g., "hexane" includes all isomers of hexane, individually or collectively). In addition, nouns using "a," "an," or "the" also include their plural forms unless expressly specified otherwise.

[0031] The terms "comprising", "including", "having" and their derivatives do not exclude the presence of any other components, steps or processes, and are irrelevant to whether these other components, steps or processes are disclosed in this application. To eliminate any doubt, unless explicitly stated, all compositions using the terms "comprising", "including", or "having" in this application may include any additional additives, adjuvants or compounds. On the contrary, except for those necessary for operating performance, the term "essentially consisting of..." excludes any other components, steps or processes from the scope of any description of the term below. The term "consisting of..." does not include any components, steps or processes that are not specifically described or listed. Unless explicitly stated, the term "or" refers to the listed individual members or any combination thereof.

[0032] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments. Example

[0033] The following examples are used to demonstrate preferred embodiments of the present invention. It will be appreciated by those skilled in the art that the techniques disclosed in the following examples represent techniques discovered by the inventors that can be used to implement the present invention and therefore can be considered as preferred embodiments of the present invention. However, it will be appreciated by those skilled in the art based on this specification that many modifications may be made to the specific embodiments disclosed herein and still achieve the same or similar results without departing from the spirit or scope of the present invention.

[0034] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, and the disclosure and materials cited therein are hereby incorporated by reference.

[0035] Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many technical equivalents to the specific embodiments of the invention described herein. Such equivalents are intended to be encompassed by the claims.

[0036] The experimental methods in the following examples are conventional methods unless otherwise specified. The instruments and equipment used in the following examples are conventional laboratory instruments and equipment unless otherwise specified; the experimental materials used in the following examples are purchased from conventional biochemical reagent stores unless otherwise specified.

[0037] Example 1 Zinc ion electrolyte #1

[0038] This embodiment provides a formula of zinc ion electrolyte #1, the solvent is composed of EC, DMC and PC in a volume ratio of 60:20:20, and the electrolyte is ZnF 12 P 2 , the concentration is 1mol / L. It also includes additives VC and FEC, with volume percentages of 2% and 1% respectively.

[0039] In this embodiment, the purity of each solvent, electrolyte and additive is greater than 99.99%, the water content in the electrolyte is less than 50 ppm, and the HF content in the electrolyte is less than 50 ppm.

[0040] Example 2 Zinc Ion Electrolyte #2

[0041] This embodiment provides another formula of zinc ion electrolyte #2, the solvent is composed of FEC, EMC and DEC in a volume ratio of 30:40:40, and the electrolyte is ZnCl 2 O 8 , the concentration is 2mol / L. It also includes additives VC and PS, with volume percentages of 2% and 1% respectively.

[0042] In this embodiment, the purity of each solvent, electrolyte and additive is greater than 99.99%, the water content in the electrolyte is less than 50 ppm, and the HF content in the electrolyte is less than 50 ppm.

[0043] Example 3 Zinc ion battery

[0044] This embodiment provides a zinc ion battery, which is composed of the electrolyte prepared in Example 1, a positive electrode, a negative electrode and a separator.

[0045] 1. Current collector

[0046] The current collector of this embodiment can be used to prepare a positive electrode sheet or a negative electrode sheet.

[0047] First, Ni is coated on both sides of the organic film, and then Cu is coated on both sides to obtain a current collector Cu / Ni / PET / Ni / Cu. The above results can be achieved by vacuum evaporation, or by vacuum evaporation followed by chemical electroplating.

[0048] 2. Positive electrode

[0049] The positive electrode sheet of this embodiment is prepared by coating the active material of the positive electrode sheet on the current collector prepared as described above. The active material of the positive electrode sheet is anhydrous Mn 3 O 4 , conductive agent carbon black and bonding PTFE, the ratio of the three is 95:2:3.

[0050] 3. Negative electrode

[0051] The negative electrode sheet of this embodiment is prepared by coating the negative electrode active material on the above current collector. The negative electrode active material is composed of Zn metal powder, conductive agent carbon nanotubes and binder CMC and SBR, and the ratio of the three is 95:2:2:1.

[0052] The surface of the Zn metal powder is coated with ZnF2 to form a coating layer, and the thickness of the coating layer is about 1-100 nm.

[0053] Finally, a protective layer is coated on both sides of the prepared negative electrode sheet. The protective layer is composed of PVDF and boehmite in a ratio of 3:7.

[0054] 4. Diaphragm

[0055] The separator of this embodiment uses PE as the substrate, and the surface is coated with boehmite.

[0056] 5. Cell Preparation

[0057] The positive electrode sheet, separator and negative electrode sheet prepared above are stacked together in sequence. Figure 1As shown, after die-cutting, stacking, and placing in the electrolyte prepared in Example 1, a zinc ion battery can be obtained.

[0058] Example 4 Battery Performance Testing

[0059] The performance test of the zinc ion battery prepared in Example 3 of the present invention was carried out, and the results are as follows: Figure 2 As shown. Figure 2 It can be seen that the energy density of the zinc ion battery prepared in Example 3 of the present invention is greater than 200Wh / k, and the life span reaches more than 1000 times.

[0060] It can be seen that the zinc ion battery prepared by Example 3 of the present invention has the characteristics of high energy density and high power. And the application temperature is wide, safe and the raw materials are cheap, and the use of organic solvent electrolyte solves the hydrolysis problem caused by water-based electrolyte, and increases the voltage of the battery at the same time. All documents mentioned in the present invention are cited as reference in this application, just as each document is cited as reference separately. In addition, it should be understood that after reading the above-mentioned teaching content of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope limited by the appended claims of the present application.

Claims

1. A zinc ion electrolyte, characterized in that The solvent of the electrolyte is composed of EC, DMC and PC in a volume ratio of 60:20:20, the electrolyte is ZnF12P2 with a concentration of 1 mol / L, and the additives VC and FEC have a volume percentage of 2% and 1% respectively; Or the solvent is composed of FEC, EMC and DEC in a volume ratio of 30:40:40, the electrolyte is ZnCl2O8 with a concentration of 2 mol / L, and the additives VC and PS have a volume percentage of 2% and 1% respectively.

2. A zinc ion battery, characterized in that: The invention comprises the electrolyte as claimed in claim 1, a positive electrode sheet, a negative electrode sheet and a separator, wherein the positive electrode sheet is prepared by coating the active material of the positive electrode sheet on the current collector of the positive electrode sheet, and the negative electrode sheet is prepared by coating the active material of the negative electrode sheet on the current collector of the negative electrode sheet.

3. The zinc ion battery according to claim 2, characterized in that The current collector is a stainless steel mesh, or is made of one or more metals selected from aluminum, nickel, titanium, copper, iron, zinc and chromium, or is made of a metal coating or an inorganic coating coated on an organic film, wherein the organic film is selected from one of PET, PP, PE, PI, PVC and OPP, and the inorganic coating is made of Al2O3, TiO2, SiO2 or Cr2O3.

4. The zinc ion battery according to claim 3, characterized in that The outer surface of the current collector is also coated with a conductive coating.

5. The zinc ion battery according to claim 2, characterized in that The active material of the positive electrode sheet includes anhydrous Mn3O4, a conductive agent and a binder; the active material of the negative electrode sheet includes Zn metal, a conductive agent and a binder.

6. The zinc ion battery according to claim 5, characterized in that The conductive agent is selected from one of a metal conductive agent, a metal oxide conductive agent, a carbon conductive agent, and a fibrous conductive agent; and the binder is selected from one of PVDF, CMC / SBR, PTFE, DMA, and acrylic glue.

7. The zinc ion battery according to claim 2, characterized in that: The diaphragm is composed of a porous material.

8. The zinc ion battery according to claim 6, characterized in that The negative electrode sheet is also coated with a protective layer, wherein the protective layer is made of organic matter, or the protective layer is a composite of organic matter and inorganic matter.

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