阅读说明：本技术 一种提高水系锌锰电池工作电压的电解液及其应用 (Electrolyte for improving working voltage of water-based zinc-manganese battery and application thereof ) 是由 方国赵 郭珊 梁叔全 刘哲轩 张腾升 马君剑 于 2020-05-21 设计创作，主要内容包括：本发明公开了一种提高水系锌锰电池工作电压的电解液,为含有三价和/或四价金属离子的水系电解液。所述水系锌锰电池为一次电池或二次电池,当水系锌锰电池为一次电池时,所述电解液为三价和/或四价金属离子的水系电解液；当水系锌锰电池为二次电池时,所述电解液为三价和/或四价金属离子、锌离子和二价锰离子的水系电解液。本发明以含三价和/或四价金属离子的电解液作为水系锌锰电池的电解液,用于改变电解液及电极/电解液界面的组成,从而改变电极与电解液之间的平衡交换电位,可以提高水系锌锰电池的工作电压、比容量等电化学性能,最终提高电池的能量密度。(The invention discloses an electrolyte for improving the working voltage of an aqueous zinc-manganese battery, which is an aqueous electrolyte containing trivalent and/or tetravalent metal ions. The water system zinc-manganese battery is a primary battery or a secondary battery, and when the water system zinc-manganese battery is the primary battery, the electrolyte is water system electrolyte of trivalent and/or quadrivalent metal ions; when the aqueous zinc-manganese battery is a secondary battery, the electrolyte is an aqueous electrolyte of trivalent and/or tetravalent metal ions, zinc ions and divalent manganese ions. The electrolyte containing trivalent and/or tetravalent metal ions is used as the electrolyte of the water system zinc-manganese battery and is used for changing the composition of the electrolyte and an electrode/electrolyte interface, so that the balance exchange potential between an electrode and the electrolyte is changed, the electrochemical properties such as working voltage, specific capacity and the like of the water system zinc-manganese battery can be improved, and the energy density of the battery is finally improved.)

1. An electrolyte for improving the working voltage of a water system zinc-manganese battery is characterized in that: the electrolyte is an aqueous electrolyte containing trivalent and/or tetravalent metal ions.

2. The electrolyte for improving the working voltage of the aqueous zinc-manganese dioxide battery according to claim 1, wherein: the water system zinc-manganese battery is a primary battery or a secondary battery, and when the water system zinc-manganese battery is a primary battery, the electrolyte is a water system electrolyte of trivalent and/or quadrivalent metal ions;

when the aqueous zinc-manganese battery is a secondary battery, the electrolyte is an aqueous electrolyte of trivalent and/or tetravalent metal ions, zinc ions and divalent manganese ions.

3. The electrolyte for improving the operating voltage of an aqueous zinc-manganese dioxide battery according to claim 1 or 2, characterized in that: the trivalent and/or tetravalent metal ion is selected from Al ³⁺ 、Fe ³⁺ 、Ti ⁴⁺ 、Ce ⁴⁺ At least one of trivalent and/or tetravalent metal ions in a concentration of 0.1 to 2mol L ^-1 。

4. The electrolyte for improving the operating voltage of an aqueous zinc-manganese dioxide battery according to claim 3, wherein: the trivalent metal ion is Al ³⁺ The concentration of the catalyst is 1 to 2mol L ^-1 。

5. Use of the electrolyte according to any of claims 1 to 4, characterized in that: the manganese-based anode material is used for a water-based zinc-manganese battery, and the anode of the water-based zinc-manganese battery is made of a manganese-based anode material.

6. Use of the electrolyte according to claim 5, characterized in that: the water system zinc-manganese battery is a primary battery, and the anode material adopts alpha-MnO ₂ (ii) a Or secondary battery, the positive electrode material adopts Ca ₂ MnO ₄ 。

7. Use of the electrolyte according to claim 6, characterized in that: in the primary battery, the water system electrolyte is water system electrolyte of trivalent and/or quadrivalent metal ions, and the total concentration of the trivalent and/or quadrivalent metal ions is 0.1-2mol L ^-1 (ii) a Or in the secondary battery, the water system electrolyte is water system electrolyte of trivalent and/or quadrivalent metal ions, zinc ions and divalent manganese ions, and the total concentration of the trivalent and/or quadrivalent metal ions is 0.1-2mol L ^-1 。

8. Use of the electrolyte according to claim 7, characterized in that: in the secondary battery, the positive electrode side is an aqueous electrolyte of trivalent and/or tetravalent metal ions and divalent manganese ions, and the concentration of the trivalent and/or tetravalent metal ions is 0.1-2mol L ^-1 The concentration of the divalent manganese ion is 0.05-0.2mol L ^-1 (ii) a The negative electrode side is an aqueous electrolyte of zinc ions and divalent manganese ions, and the concentration of the zinc ions is 0.5-3mol L ^-1 The concentration of the divalent manganese ion is 0.05-0.2mol L ^-1 。

Technical Field

The invention belongs to the technical field of aqueous zinc-ion battery electrolyte, relates to electrolyte for improving the working voltage of an aqueous zinc-manganese battery and application thereof, and particularly relates to aqueous zinc-manganese battery electrolyte containing trivalent and/or tetravalent metal ions for improving the working voltage of the aqueous zinc-manganese battery and application thereof.

Background

The water system zinc ion battery is expected to become a next generation new energy storage system due to the advantages of safety, environmental protection and low price. The manganese-based material is the most suitable anode material for the current water system zinc ion battery due to the advantages of no toxicity, high working voltage and high specific capacity. However, in practical applications, the operating voltage is still a major factor that restricts the further widespread use of aqueous zinc-manganese batteries. At present, the conventional zinc sulfate electrolyte is used, the working voltage of the water system zinc-manganese battery is only about 1.25V, and the working voltage of the vanadium-based material is lower and is only about 0.8V. If the specific capacity of the battery is 300mA h g ^-1 The energy density is only 375 Wkg by using the conventional zinc sulfate electrolyte ^-1 . If it is workingThe energy density can be improved by 30W h kg for every 0.1V of voltage increase ^-1 . Therefore, compared with the improvement of the specific capacity performance of the battery, the improvement of the working voltage index of the battery is more important.

At present, the method for improving the working voltage of the aqueous zinc ion battery is mainly to change the properties of a positive electrode material, such as a Prussian blue analogue used as a positive electrode. However, the method is complex, the reaction involves cyanide ligand with high toxicity, the requirement of green environmental protection is not met, the preparation difficulty is high, the method is not suitable for mass production, and the method for changing the anode material is always limited. Considering that the magnitude of the electrode potential is related to the electrode and the electrolyte, changing the electrode potential by changing the electrolyte environment is a feasible method for changing the electromotive force of the battery. At present, in the aspect of changing the electrolyte environment, the voltage of an aqueous zinc-manganese battery is generally improved by using an ionic liquid electrolyte with ultrahigh concentration, but the electrolyte is too expensive, is not environment-friendly and is not suitable for large-scale use.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide an electrolyte for improving the working voltage of an aqueous zinc-manganese battery, which takes an electrolyte containing trivalent and/or tetravalent metal ions as the electrolyte of the aqueous zinc-manganese battery and is used for changing the compositions of the electrolyte and an electrode/electrolyte interface so as to change the balance exchange potential between an electrode and the electrolyte, improve the electrochemical properties such as the working voltage, specific capacity and the like of the aqueous zinc-manganese battery and finally improve the energy density of the battery.

In order to achieve the technical purpose, the invention adopts the following technical scheme:

an electrolyte for improving the working voltage of an aqueous zinc-manganese battery is an aqueous electrolyte containing trivalent and/or tetravalent metal ions.

Preferably, the aqueous zinc-manganese battery is a primary battery or a secondary battery, and when the aqueous zinc-manganese battery is a primary battery, the electrolyte is an aqueous electrolyte of trivalent and/or quadrivalent metal ions;

when the aqueous zinc-manganese battery is a secondary battery, the electrolyte is an aqueous electrolyte of trivalent and/or tetravalent metal ions, zinc ions and divalent manganese ions.

Preferably, the trivalent and/or tetravalent metal ion is selected from Al ³⁺ 、Fe ³⁺ 、Ti ⁴⁺ 、Ce ⁴⁺ At least one of trivalent and/or tetravalent metal ions in a concentration of 0.1 to 2mol L ^-1 。

More preferably, the trivalent metal ion is Al ³⁺ The concentration of the catalyst is 1 to 2mol L ^-1 。Al ³⁺ The electrolyte has good stability and high safety, and the solution of soluble aluminum salt (such as aluminum sulfate, aluminum chloride, aluminum nitrate, aluminum trifluoromethanesulfonate and the like) is preferably adopted as the electrolyte of the primary battery; or the electrolyte is added into zinc ion and divalent manganese ion electrolyte to be used as electrolyte of a secondary battery, trivalent aluminum ions have higher valence than divalent zinc ions and smaller ionic radius than divalent zinc ions, and are more favorable for anode reaction.

The invention also provides application of the electrolyte, and the electrolyte is used for an aqueous zinc-manganese battery, and the anode of the aqueous zinc-manganese battery adopts manganese-based anode materials, such as manganese dioxide, manganese sesquioxide, manganous oxide, manganese monoxide, lithium manganate, calcium manganate, magnesium manganate, sodium manganate, potassium manganate and the like.

Preferably, the water-based zinc-manganese battery is a primary battery, and the anode material adopts alpha-MnO ₂ (ii) a Or secondary battery, the positive electrode material adopts Ca ₂ MnO ₄ 。

More preferably, in the primary battery, the electrolyte is an aqueous electrolyte of trivalent and/or quadrivalent metal ions, and the total concentration of the trivalent and/or quadrivalent metal ions is 0.1 to 2mol L ^-1 (ii) a Or in the secondary battery, the electrolyte is an aqueous electrolyte of trivalent and/or tetravalent metal ions, zinc ions and divalent manganese ions, and the total concentration of the trivalent and/or tetravalent metal ions is 0.1-2mol L ^-1 。

Most preferably, in the secondary battery, the positive electrode side is an aqueous electrolyte of a trivalent and/or tetravalent metal ion and a divalent manganese ion, and the concentration of the trivalent and/or tetravalent metal ion is 0.1 to 2mol L ^-1 The concentration of the divalent manganese ion is 0.05-0.2mol L ^-1 (ii) a The negative electrode side is an aqueous electrolyte containing zinc ions and divalent manganese ions, and the concentration of the zinc ions is 0.5-3mol L ^-1 The concentration of the divalent manganese ion is 0.05-0.2mol L ^-1 。

The aqueous zinc-manganese battery electrolyte not only inherits the advantages of safety, environmental protection, high conductivity and low cost and simple preparation of the aqueous battery, but also introduces trivalent and/or quadrivalent high valence metal ions (such as Al) into the conventional electrolyte (such as zinc sulfate aqueous electrolyte, zinc trifluoromethanesulfonate aqueous electrolyte, zinc chloride aqueous electrolyte, zinc nitrate aqueous electrolyte, zinc perchlorate aqueous electrolyte, zinc acetate aqueous electrolyte, zinc iodide aqueous electrolyte and the like) of the aqueous zinc-manganese battery ³⁺ 、Fe ³⁺ 、Ti ⁴⁺ 、Ce ⁴⁺ Etc.), so as to change the electrolyte and the composition of the electrode/electrolyte interface, thereby changing the balance exchange potential between the electrode and the electrolyte, and improving the electrochemical properties of the water system zinc-manganese ion battery, such as working voltage, specific capacity and the like, and finally improving the energy density of the battery.

Compared with the prior art, the invention has the following advantages:

(1) Compared with the conventional electrolyte (such as zinc sulfate aqueous electrolyte, zinc trifluoromethanesulfonate aqueous electrolyte, zinc chloride aqueous electrolyte, zinc nitrate aqueous electrolyte, zinc perchlorate aqueous electrolyte, zinc acetate aqueous electrolyte, zinc iodide aqueous electrolyte and the like) of the conventional aqueous zinc-manganese battery, the aqueous electrolyte containing trivalent and/or tetravalent metal ions is prepared by adding alpha-MnO ₂ As a primary battery of the anode, the first circle of the conventional zinc sulfate aqueous electrolyte has a working voltage platform of 1.25V (the specific capacity is 220mA h g) ^-1 ) And the first circle of discharge platforms of the aluminum sulfate aqueous electrolyte are two and are respectively 1.65V (the specific capacity is 230mA h g) ^-1 ) And 1.3V (specific capacity of 280mA h g) ^-1 ) The zinc sulfate electrolyte has higher working voltage than the conventional zinc sulfate electrolyte, and more than two times of the capacity of the conventional zinc sulfate electrolyte.

(2) Compared with the conventional electrolyte (such as sulfuric acid) of the conventional aqueous zinc-manganese battery, the aqueous electrolyte containing trivalent and/or tetravalent metal ions of the inventionZinc aqueous electrolyte, zinc trifluoromethanesulfonate aqueous electrolyte, zinc chloride aqueous electrolyte, zinc nitrate aqueous electrolyte, zinc perchlorate aqueous electrolyte, zinc acetate aqueous electrolyte, zinc iodide aqueous electrolyte, etc.) with Ca ₂ MnO ₄ The voltage window of the secondary battery as the anode is increased from the original 0.8-1.8V to the current 0.8-2V, and the voltage window is increased by 0.2V; the charging voltage peak is increased by 0.32V, the two discharging voltage peaks are increased by 0.31V and 0.07V respectively, the voltage window can be widened, and the working voltage platform can be improved.

Drawings

Fig. 1 is a first-turn discharge graph of the battery in comparative example 1.

Fig. 2 is a graph of the first cycle discharge of the battery in example 1.

Fig. 3 is a graph comparing Cyclic Voltammograms (CVs) of the cells of comparative example 2 and example 2.

Fig. 4 is a second cycle constant current charge and discharge (GCD) comparison of the batteries of comparative example 2 and example 2.

FIG. 5 shows the current density of 1Ag for the battery of example 2 ^-1 Long cycle performance plot under the conditions of (1).

Detailed Description

The invention is further illustrated by the following examples, which are intended to be illustrative of the invention and are not intended to be limiting, and the starting materials of the invention are commercially available, and the methods of preparation of the invention are conventional in the art unless otherwise specified.

Comparative example 1

Using alpha-MnO ₂ Is a positive electrode, 2mol L ^-1 The zinc sulfate is used as electrolyte, and the zinc sheet is used as a negative electrode, and the battery is assembled for testing.

Comparative example 2

Using Ca ₂ MnO ₄ As a positive electrode, 2mol L ^-1 Adding 0.1m of zinc sulfateol L ^-1 The manganese sulfate is used as electrolyte, the zinc sheet is used as a negative electrode, and the battery is assembled for testing.