Aqueous zinc-manganese battery structure based on multi-electron reaction

Abstract

The invention relates to the technical field of electrochemical energy storage batteries, in particular to an aqueous zinc-manganese battery structure based on multi-electron reaction. According to the technical scheme, the lithium ion battery comprises a negative electrode, a positive electrode and a porous diaphragm for separating the positive electrode from the negative electrode, an electrolyte chamber is divided into a negative electrolyte chamber and a positive electrolyte chamber by the porous diaphragm, and the volume of the negative electrolyte chamber is smaller than that of the positive electrolyte chamber, namely, the volume ratio X is equal to Vpositive / Vnegative gt; 1; the electrolyte in the positive electrode electrolyte chamber can contain H < + > before being in a working state; h < + > initially added into the electrolyte in the positive electrode electrolyte bin or H < + > generated in the charging process migrates to the electrolyte in the negative electrode bin under the driving force of the concentration difference. According to the high-energy-density water-based zinc-manganese battery and the preparation method thereof, the anti-corrosion speed of the zinc metal negative electrode in the high-energy-density water-based zinc-manganese battery in the electrolyte containing H < + > is reduced by utilizing the unequal-volume positive and negative electrode compartment battery structure design, so that the service life of the high-energy-density water-based zinc-manganese battery based on the multi-electron reaction is prolonged, and the effect is remarkable.

Description

Technical Field

[0001] The present invention relates to the technical field of electrochemical energy storage batteries, and in particular to an aqueous zinc-manganese battery structure based on multi-electron reactions. Background Art

[0002] With the rapid development of new green energy sources such as solar energy and wind energy, electric vehicles and consumer electronic devices, their demand for energy storage devices is also increasing. Therefore, the development of safe, low-cost, high-energy-density batteries has become one of the important goals in the energy development strategies of various countries. Although organic lithium-ion batteries are technologically mature and have high energy density, they have problems such as flammable organic electrolytes and high preparation costs. In contrast, aqueous batteries have the advantages of non-flammable electrolytes and low preparation costs, and thus have attracted much attention. However, common aqueous batteries are limited by side reactions such as hydrogen evolution and oxygen evolution, which causes the battery voltage to be low, thereby limiting the battery's energy density. Since the energy density of the battery is directly related to the battery voltage, the concentration of the active material and the number of electron transfers of the active material, especially the increase in the number of electron transfers can multiply the energy density of the battery, therefore, the development of electrochemical reactions with multiple electron transfers is an important strategy for constructing high-energy-density battery systems. Among them, the Mn-based 2+ / MnO2 deposition and dissolution cathode reaction and Zn / Zn 2+ The aqueous zinc-manganese battery developed by deposition-dissolution negative electrode reaction has high discharge voltage (≥1.95V) and two-electron transfer reaction, which has low price, high safety, high theoretical capacity (MnO2: 616mAh g -1 、Zn:820mAh g-1 / 5851mAh mL -1 ), etc., so it shows great application potential.

[0003] But according to Mn 2+ / MnO2 deposition and dissolution cathode reaction mechanism: This reaction requires not only the presence of H + It can show good reversibility in the electrolyte, and H + However, the contradiction is that the zinc metal negative electrode and H + There is a strong reaction activity between the zinc metal negative electrode and H + Corrosion and generation of hydrogen ( This side reaction not only causes the loss of negative electrode active materials and shortens the battery cycle life, but also consumes H in the electrolyte. + , which causes H in the electrolyte +The problem of reduced cathode reversibility caused by decreased concentration has limited the development and use of high-energy-density aqueous zinc-manganese batteries. Several strategies have been proposed to address this issue, such as using corrosion-resistant zinc alloys, constructing artificial protective layers on zinc metal, introducing proton-scavenging agents into the electrolyte, or using separators with proton-scavenging capabilities. While these methods all have the effect of mitigating zinc metal anode corrosion, research on mitigating zinc metal anode corrosion through battery structural design has not been reported.

[0004] Therefore, the present invention reduces the corrosion problem of the zinc metal negative electrode in high energy density aqueous zinc-manganese battery by adopting a positive and negative electrode compartment structure design with unequal volumes, and has achieved significant results. Summary of the Invention

[0005] The purpose of this invention is to enhance the performance of zinc metal negative electrode in H-containing + Corrosion resistance in electrolyte, improving the cycle life of high energy density aqueous zinc-manganese battery system based on multi-electron transfer reaction, and proposing an aqueous zinc-manganese battery structure based on multi-electron reaction.

[0006] The technical solution of the present invention is: an aqueous zinc-manganese battery structure based on a multi-electron reaction, comprising a negative electrode, a positive electrode, and a porous diaphragm separating the positive and negative electrodes, wherein the porous diaphragm separates the electrolyte compartment into a negative electrode electrolyte compartment and a positive electrode electrolyte compartment, wherein the volume of the negative electrode electrolyte compartment is smaller than that of the positive electrode electrolyte compartment, i.e., the volume ratio X=V 正 / V 负 >1; H in the cathode electrolyte compartment + Migration to the negative electrode electrolyte compartment under the driving force of concentration difference, the migration process has at least two stages:

[0007] First migration phase: H + Rapid transmission, due to the small volume of the negative electrolyte chamber, when a small amount of H + When it is transferred to the negative electrode electrolyte chamber, the H + The concentration rises rapidly, causing H + The concentration difference decreases rapidly;

[0008] Second migration phase: H + The transmission speed drops rapidly, causing the H transferred from the positive electrolyte chamber to the negative electrolyte chamber per unit time to + The total amount is reduced to alleviate the corrosion of the zinc negative electrode.

[0009] Optionally, the electrolyte in the cathode electrolyte chamber may contain H + , the H initially added to the electrolyte in the cathode electrolyte compartment + Or H generated during charging +Migrate to the electrolyte in the negative electrode compartment under the driving force of the concentration difference.

[0010] Optionally, the porous diaphragm is a PP / PE diaphragm, an ion exchange membrane, a fiberglass diaphragm, a polyvinylidene fluoride membrane or any other porous diaphragm that allows H + , to pass through.

[0011] Optionally, the electrode material in the negative electrode electrolyte compartment is zinc metal, and the positive electrode current collector in the positive electrode electrolyte compartment includes any one of carbon felt, carbon cloth, carbon paper, and titanium foil.

[0012] Optionally, the positive electrode current collector can be loaded with a manganese-based material, and the manganese-based material includes one or more of MnO2, Mn2O3, and Mn3O4.

[0013] Optionally, the electrolyte composition in the positive electrode electrolyte compartment includes 0.5 - 5 mol / L of MnSO4, 0.5 - 5 mol / L of ZnSO4, and 0.05 - 0.3 mol / L of H2SO4, and the electrolyte composition in the negative electrode electrolyte compartment includes 0.5 - 5 mol / L of MnSO4 and 0.5 - 5 mol / L of ZnSO4.

[0014] Compared with the prior art, the present invention has the following beneficial technical effects:

[0015] The present invention uses the battery structure design of unequal volumes of positive and negative electrode compartments to reduce the corrosion resistance speed of the zinc metal negative electrode in the H + -containing electrolyte in the high-energy density aqueous zinc-manganese battery, so as to improve the service life of the high-energy density aqueous zinc-manganese battery based on multi-electron reactions. The effect is remarkable. Compared with the service life of about 5 hours of the zinc-manganese battery with a traditional structure, the aqueous zinc-manganese battery of the present invention can provide a cycle life exceeding 2000 hours and is suitable for electrochemical energy storage systems such as solar energy storage, wind energy storage, or electric vehicle power sources. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic diagram of the structure of the aqueous zinc-manganese battery of the present invention;

[0017] Figure 2 is a schematic diagram of the transmission speed of H + transported from the positive electrode compartment electrolyte to the negative electrode compartment electrolyte in the battery structures of two different positive and negative compartment volume ratios X(a) < X(b) of the present invention;

[0018] Figure 3 is a comparative test chart of the cycle life of the high-energy density aqueous zinc-manganese full battery based on the conventional non-compartment structure design and the battery structure design of the present invention.

[0019] Reference Signs:

[0020] 1. Negative electrode;

[0021] 2. Positive electrode;

[0022] 3. Porous diaphragm;

[0023] 4. Negative electrolyte chamber;

[0024] 5. Positive electrode electrolyte chamber. DETAILED DESCRIPTION

[0025] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0026] In the description of the present invention, it should be noted that the terms "upper," "lower," "inner," "outer," "front end," "rear end," "both ends," "one end," "the other end," and the like, indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0027] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "provided with," "connected," etc., should be understood in a broad sense. For example, "connected" may refer to a fixed connection, a detachable connection, or an integral connection; it may refer to a mechanical connection or an electrical connection; it may refer to a direct connection or an indirect connection through an intermediate medium; it may refer to internal communication between two components. Those skilled in the art will be able to understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0028] like Figure 1 As shown, the present invention proposes an aqueous zinc-manganese battery structure based on multi-electron reaction, including a negative electrode 1, a positive electrode 2 and a porous separator 3 for separating the positive and negative electrodes. The porous separator 3 is a membrane that allows H +, Zn²⁺ through any of the PP / PE membranes, ion exchange membranes, glass fiber membranes, polyvinylidene fluoride membranes, or other porous membranes. The porous membrane 3 separates the electrolyte chamber into a negative electrolyte chamber 4 and a positive electrolyte chamber 5. The electrode material in the negative electrolyte chamber 4 is zinc metal. The positive electrode current collector in the positive electrolyte chamber 5 includes any of carbon felt, carbon cloth, carbon paper, and titanium foil. The positive electrode current collector may also be loaded with a manganese-based material, including one or more of MnO2, Mn2O3, and Mn3O4.

[0029] It should be noted that the volume of the negative electrode electrolyte chamber 4 of the present invention is smaller than the volume of the positive electrode electrolyte chamber 5, that is, the volume ratio X=V 正 / V 负 >1.

[0030] When assembled into a zinc-manganese full battery, the electrolyte in the positive electrode electrolyte compartment 5 can be added with a certain amount of H as needed. + , and the electrolyte in the negative electrode electrolyte chamber 4 is not added with H + Except for the above, the rest of the components are consistent with the electrolyte components in the positive electrode electrolyte chamber 5. For example, the electrolyte components in the positive electrode electrolyte chamber 5 include 0.5-5 mol / L MnSO4, 0.5-5 mol / L ZnSO4, and 0.05-0.3 mol / L H2SO4, and the electrolyte components in the negative electrode electrolyte chamber 4 include 0.5-5 mol / L MnSO4 and 0.5-5 mol / L ZnSO4. When the battery is assembled and left to stand or run, the H2SO4 initially added to the electrolyte in the positive electrode electrolyte chamber 5 is + Or H generated during charging + Under the driving force of concentration difference, H migrates to the electrolyte in the negative electrode electrolyte compartment 4, resulting in H + The concentration of H increases, which leads to corrosion of the zinc metal negative electrode. + The transmission from the positive electrode compartment to the negative electrode compartment occurs under the action of the concentration difference driving force, and this effect is that the greater the concentration difference between the two sides, the greater the H + The faster the transmission rate, the more H is transmitted to the negative electrode electrolyte chamber 4 and reacts with the zinc metal negative electrode per unit time. + The more the amount, the more serious the corrosion of the zinc metal negative electrode will be. Therefore, in view of this principle, the present invention weakens this driving force by designing positive and negative chambers with X>1. The working principle of the present invention is as follows Figure 2 As shown, when H + When the concentration is higher than that in the negative electrode electrolyte chamber 4, the H + Under the driving force of concentration difference, it begins to be transported to the negative electrode electrolyte chamber 4. As the volume of the negative electrode electrolyte chamber 4 decreases, when a small amount of H+ When the H + The concentration will rise rapidly, causing the H + The concentration difference decreases rapidly, causing H + The transmission driving force of H + The transmission speed drops rapidly, so that the H transferred from the positive electrode 2 side to the negative electrode electrolyte chamber 4 per unit time is + The total amount is reduced, thereby achieving the purpose of alleviating zinc negative electrode corrosion. According to the principle of the present invention, it can be known that the smaller the volume of the negative electrode electrolyte chamber 4, the better the effect of alleviating zinc negative electrode corrosion.

[0031] It should be noted that the present invention is for zinc metal negative electrode in the presence of H + The improvement of corrosion resistance in the electrolyte is very obvious, and it has obvious advantages compared with the existing technology for overcoming the problem of corrosion of zinc metal negative electrode. + In the electrolyte (the zinc metal electrode inserted into the electrolyte can be completely corroded), two zinc-manganese batteries a and b (where 1 < <X a <X b ) have cycle lives exceeding 800h and 2000h, respectively, while conventional zinc-manganese batteries that do not adopt a compartmentalized structure have a cycle life of only about 5h, after which the zinc metal negative electrode is completely corroded. Furthermore, the cycle life of batteries a and b in the present invention is also superior to currently reported designs with equal-volume compartmentalized structures (e.g., ACS Applied Materials & Interfaces, 2022, 14(46):51900-51909 and Nature Energy, 2020, 5(6):440-449), demonstrating significant superiority.

[0032] Further, the zinc metal electrode and the carbon felt electrode of the same area size and thickness are respectively assembled in a conventional non-compartment structure battery and a battery a and b with a compartment structure in the present invention, wherein 1< <X a <X b (i.e. V 正a =V 正b , V 负a >V 负b ). Add sufficient H to the conventional non-compartment structure battery and the positive electrode compartment of battery a and b respectively. + Acidic electrolyte, and add H-free to the negative electrolyte chamber 4 of battery a, b + The rest of the components are the same as the electrolyte in the positive electrode electrolyte compartment 5. The test parameters of the zinc-manganese full battery are 2.2 V constant voltage charging 1 mAh cm -2, then discharge to 0.8 V at 1C constant current. The test results are as follows Figure 3 As shown, a conventional zinc-manganese battery without a compartmentalized design cycled for approximately 5 hours before the zinc metal negative electrode completely corroded and shorted. However, two zinc-manganese batteries (a) and (b) based on the battery structure of the present invention achieved cycle lives exceeding 800 hours and 2000 hours, respectively, demonstrating the significant superiority of the present invention.

[0033] The above specific embodiments are merely several optional embodiments of the present invention. Based on the technical solutions of the present invention and the relevant inspirations of the above embodiments, those skilled in the art may make various alternative improvements and combinations to the above specific embodiments.

Claims

1. An aqueous zinc-manganese battery structure based on a multi-electron reaction, comprising a negative electrode (1), a positive electrode (2), and a porous diaphragm (3) for separating the positive and negative electrodes, wherein the porous diaphragm (3) separates the electrolyte compartment into a negative electrode electrolyte compartment (4) and a positive electrode electrolyte compartment (5), characterized in that: The volume of the negative electrode electrolyte chamber (4) is smaller than the volume of the positive electrode electrolyte chamber (5), that is, the volume ratio X=V 正 / V 负 >1; The H in the positive electrolyte chamber (5) + The electrolyte migrates to the negative electrode electrolyte compartment (4) under the driving force of the concentration difference. The migration process has at least two stages: First migration phase: H + Rapid transmission, due to the small volume of the negative electrolyte chamber (4), when a small amount of H + When the electrolyte in the negative electrode electrolyte chamber (4) is transferred to the negative electrode electrolyte chamber (4), H + The concentration rises rapidly, causing H + The concentration difference decreases rapidly; Second migration phase: H + The transmission speed drops rapidly, so that the H transferred from the positive electrolyte chamber (5) to the negative electrolyte chamber (4) per unit time is + The total amount is reduced to alleviate the corrosion of the zinc negative electrode.

2. The aqueous zinc-manganese battery structure based on multi-electron reaction according to claim 1, characterized in that: The electrolyte in the positive electrode electrolyte chamber (5) may contain H before the working state. + , the H initially added to the electrolyte in the positive electrode electrolyte chamber (5) + Or H generated during charging + Migrate to the negative electrode compartment electrolyte under the driving force of concentration difference.

3. The aqueous zinc-manganese battery structure based on multi-electron reaction according to claim 1, characterized in that: The porous membrane (3) allows H + , Zn²⁺ through any of the PP / PE membrane, ion exchange membrane, glass fiber membrane or polyvinylidene fluoride membrane.

4. The aqueous zinc-manganese battery structure based on multi-electron reaction according to claim 1, characterized in that: The electrode material in the negative electrode electrolyte chamber (4) is zinc metal, and the positive electrode current collector in the positive electrode electrolyte chamber (5) includes any one of carbon felt, carbon cloth, carbon paper, and titanium foil.

5. The aqueous zinc-manganese battery structure based on multi-electron reaction according to claim 4, characterized in that: The positive electrode current collector may be loaded with a manganese-based material, and the manganese-based material includes one or more of MnO 2 , Mn 2 O 3 , and Mn 3 O 4 .

6. The aqueous zinc-manganese battery structure based on multi-electron reaction according to claim 5, characterized in that: The electrolyte components in the positive electrode electrolyte chamber (5) include 0.5-5 mol / L MnSO4, 0.5-5 mol / L ZnSO4, and 0.05-0.3 mol / L H2SO4, and the electrolyte components in the negative electrode electrolyte chamber (4) include 0.5-5 mol / L MnSO4 and 0.5-5 mol / L ZnSO4.

7. An application of a multi-electron reaction aqueous battery, characterized in that: The aqueous zinc-manganese battery structure according to any one of claims 1 to 6 is used in electrochemical energy storage systems, including but not limited to solar energy storage, wind energy storage or electric vehicle power supply.

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