Organic small-molecule electrolyte additive and application thereof

Abstract

The application provides an organic small-molecule electrolyte additive and application, and relates to the technical field of batteries. The organic small molecule is a carbon-containing three-membered ring alcohol small molecule, specifically, cyclopropanol, and the content of the electrolyte additive is 1%-10% v / v. Due to the metastable three-membered ring structure in the molecular structure of cyclopropanol, the ring-opening reaction is easily generated in the charging and discharging process, the electrode / electrolyte interface structure is reshaped, and the electrochemical performance is improved. Compared with conventional isopropyl alcohol, the cyclopropanol of the application can achieve the effect that excellent electrochemical performance can be presented only by adding a small amount of additive. The cyclopropanol has water solubility and organic co-solubility, and can form a uniform solution, and can be used in monovalent to multivalent ion energy storage systems of lithium, sodium, potassium, zinc, calcium, magnesium, cadmium, tin, aluminum, iron and the like, and will not have a negative impact on the solubility of the electrolyte, maintaining the high ionic conductivity of the electrolyte, which is simple, low in cost and good in application prospect.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and in particular to an organic small molecule electrolyte additive and its application. Background Technology

[0002] Batteries, as an indispensable core of energy storage, have become deeply integrated into all aspects of human society. However, diverse application scenarios place increasingly stringent demands on their performance. The electrolyte, as a key component connecting all the chemical reactions within the battery, fundamentally determines the battery's performance and application areas through its properties and interfacial behavior. Among the many limiting factors, the continuous side reactions occurring at the electrolyte-electrode interface, such as electrolyte decomposition, electrode corrosion, and gas generation, have become key bottlenecks hindering significant improvements in battery performance.

[0003] To address this challenge, electrolyte additive strategies have emerged and become a research hotspot. By introducing small amounts of specifically functional soluble substances into the base electrolyte, the solvation structure of lithium ions can be precisely altered, preferentially triggering chemical reactions on the electrode surface. This reshapes and stabilizes the electrolyte / electrode interface structure, constructing a robust and efficient ion conduction barrier. Due to its simplicity, low cost, and seamless integration with existing battery manufacturing processes, the electrolyte additive strategy demonstrates enormous engineering application potential and is expected to drive further development in the battery field.

[0004] Batteries play a crucial role in marine energy storage technology, encompassing microgrids on remote islands, smooth output of renewable energy from the sea, power for ocean-going vessels, and long-term deployed marine observation equipment, serving as a vital support for the future blue economy. However, the harsh marine environment, with its high humidity, high salt spray, and extremely high safety and reliability requirements, presents unprecedented challenges to the intricate chemical system of batteries. To meet the demands of marine facilities for ultra-long cycle life and high energy density, the development of an electrolyte additive to address interfacial side reactions and improve electrochemical performance is of significant practical importance. Summary of the Invention

[0005] Therefore, this invention proposes an organic small molecule electrolyte additive and its application.

[0006] The technical solution of this invention is implemented as follows:

[0007] An organic small molecule electrolyte additive, wherein the organic small molecule is an alcohol small molecule containing a carbon three-membered ring; the alcohol small molecule containing a carbon three-membered ring is cyclopropanol; and the content of the organic small molecule electrolyte additive is 1%-10% v / v.

[0008] Cyclopropanol, with the molecular formula C3H6O, is an organic compound that is liquid at room temperature. Its molecular structure contains a carbon-containing three-membered ring.

[0009] Application of an organic small molecule electrolyte additive in the preparation of electrolytes.

[0010] Furthermore, the electrolyte comprises a solute, a solvent, and the aforementioned additives.

[0011] Furthermore, the concentration of the solute in the electrolyte is 1-4 mol / L.

[0012] Furthermore, the solvent content in the electrolyte is 41.2%-85.3% v / v.

[0013] Furthermore, the solvent is deionized water or artificial seawater.

[0014] Furthermore, the artificial seawater contains sodium ions at 107216.48 ppm, magnesium ions at 1416.88 ppm, potassium ions at 399.01 ppm, calcium ions at 407.43 ppm, chloride ions at 19939.54 ppm, bromide ions at 56.22 ppm, and sulfate ions at 2644.59 ppm.

[0015] Furthermore, the solute is ZnSO4.

[0016] Furthermore, the preparation method of the electrolyte is as follows: the solute is added to the solvent to prepare a mixture, then the additive is added, the mixture is shaken and stirred, and ultrasonically mixed to obtain the electrolyte.

[0017] Compared with the prior art, the beneficial effects of the present invention are:

[0018] 1. Cyclopropanol, with the molecular formula C3H6O, is a liquid organic compound at room temperature. Its molecular structure contains a carbon-containing three-membered ring, and it is both water-soluble and organically co-soluble, easily forming a homogeneous solution. It can be used in energy storage systems for monovalent to multivalent ions such as lithium, sodium, potassium, zinc, calcium, magnesium, cadmium, tin, aluminum, and iron without negatively affecting the solubility of the electrolyte, maintaining the high ionic conductivity of the electrolyte. It is simple to implement, low in cost, and has good application prospects.

[0019] 2. Cyclopropanol, due to its metastable three-membered ring structure, readily undergoes ring-opening reactions during charge and discharge, reshaping the electrode / electrolyte interface structure and improving electrochemical performance. Compared to conventional isopropanol, the cyclopropanol of this invention achieves excellent electrochemical performance with only trace amounts of additives, exhibiting superior cycling performance. Attached Figure Description

[0020] Figure 1 The structural formulas are those of cyclopropanol, the additive in Example 1, and isopropanol, the additive in Comparative Example 2.

[0021] Figure 2 Raman diagrams of the electrolytes of Example 1 and Comparative Examples 1-2.

[0022] Figure 3 The images show the FTIR spectra of the electrolytes in Example 1 and Comparative Examples 1-2.

[0023] Figure 4 The symmetrical cells assembled for Example 1 and Comparative Example 1 were tested at 1 mA·cm⁻¹. -2 1 mAh•cm -2 The XRD pattern after 10 cycles.

[0024] Figure 5 The symmetrical cells assembled for Example 1 and Comparative Examples 1-2 were tested at 1 mA•cm. -2 1 mAh•cm -2 and 5 mA•cm -2 5 mAh•cm -2 The following is a graph showing the cyclic performance.

[0025] Figure 6 The symmetrical cells assembled for Example 1 and Comparative Example 1 were tested at 1 mA·cm⁻¹. -2 1 mAh•cm - The SEM cross-sectional image is magnified 500 times after 10 cycles.

[0026] Figure 7 The symmetrical cells assembled for Example 1 and Comparative Example 1 were tested at 1 mA·cm⁻¹. -2 1 mAh•cm -2 The frontal SEM image after 10 cycles.

[0027] Figure 8 In-situ optical images of the symmetrical cells assembled in Example 1 and Comparative Example 1.

[0028] Figure 9 The in-situ pH test diagrams are for the symmetrical cells assembled in Example 1 and Comparative Example 1.

[0029] Figure 10 The graph shows the cycling performance of the zinc-manganese full cells assembled in Example 1 and Comparative Example 1 at a current density of 0.3C.

[0030] Figure 11 The graph shows the cycle performance of the symmetrical batteries assembled in Example 1 and Comparative Example 1 using artificial seawater as the electrolyte solvent. Detailed Implementation

[0031] To better understand the technical content of this invention, specific embodiments are provided below to further illustrate the invention.

[0032] Unless otherwise specified, the experimental methods used in the embodiments of this invention are all conventional methods.

[0033] Unless otherwise specified, all materials and reagents used in the embodiments of this invention are commercially available.

[0034] The artificial seawater of this invention contains sodium ions at 107216.48 ppm, magnesium ions at 1416.88 ppm, potassium ions at 399.01 ppm, calcium ions at 407.43 ppm, chloride ions at 19939.54 ppm, bromide ions at 56.22 ppm, and sulfate ions at 2644.59 ppm.

[0035] Example 1

[0036] Electrolyte composition:

[0037]

[0038] Electrolyte preparation method: Add solute to solvent to prepare mixture, then add additive, shake and stir, sonicate for 30 minutes, mix evenly to obtain electrolyte.

[0039] Example 2

[0040] Electrolyte composition:

[0041]

[0042] Electrolyte preparation method: Add solute to solvent to prepare mixture, then add additive, shake and stir, sonicate for 30 minutes, mix evenly to obtain electrolyte.

[0043] Example 3

[0044] Electrolyte composition:

[0045]

[0046] Electrolyte preparation method: Add solute to solvent to prepare mixture, then add additive, shake and stir, sonicate for 30 minutes, mix evenly to obtain electrolyte.

[0047] Comparative Example 1

[0048] The difference from Example 1 is that no electrolyte additive is added; otherwise, it is the same as Example 1.

[0049] That is, the composition of the electrolyte in this comparative example:

[0050]

[0051] Electrolyte preparation method: Add solute to solvent to prepare electrolyte.

[0052] Comparative Example 2

[0053] The difference from Example 1 is that the electrolyte additive is isopropanol, while the rest is the same as in Example 1.

[0054] That is, the composition of the electrolyte in this comparative example:

[0055]

[0056] Electrolyte preparation method: Add solute to solvent to prepare mixture, then add additive, shake and stir, sonicate for 30 minutes, mix evenly to obtain electrolyte.

[0057] result

[0058] See Figure 1 The structural formulas of cyclopropanol (additive) in Example 1 and isopropanol (additive) in Comparative Example 2 are shown. It can be seen that the three-membered ring structure of cyclopropanol allows it to be in a metastable state, undergoing a ring-opening reaction during charge and discharge to reshape the electrode / electrolyte interface. In contrast, the simple chain structure of isopropanol is unstable and cannot reshape the electrode / electrolyte interface.

[0059] See Figure 2 Raman spectroscopy diagrams of the electrolytes of Example 1 and Comparative Examples 1-2. Figure 3 The FTIR spectra of the electrolytes of Example 1 and Comparative Examples 1-2 show that the microscopic solvation structures of the electrolytes of Example 1 and Comparative Examples 1-2 are not significantly different, indicating that adding a small amount of additives will not have a significant impact on the phase stability of the electrolyte.

[0060] Test case

[0061] The electrolytes prepared in Example 1 and Comparative Examples 1-2 of this invention were used to assemble batteries. Taking a zinc metal battery as an example, the specific process was as follows: a zinc foil with a thickness of 100 micrometers was punched into a circular piece with a diameter of 12 mm as an electrode sheet. The assembled button battery model was CR2032. The separator was a GF / D glass fiber separator, and the electrolyte quantity was 100 microliters. In the zinc-manganese battery, one side of the zinc metal electrode was replaced with a manganese dioxide electrode sheet. Battery performance was then tested.

[0062] See Figure 4 The symmetrical cells assembled in Example 1 and Comparative Example 1 were tested at 1 mA·cm⁻¹. -2 1 mAh•cm -2 The XRD pattern after 10 cycles shows that the peaks of the byproducts in Comparative Example 1 are sharp and obvious, while no peaks corresponding to the byproducts appear in Example 1. This indicates that the electrolyte prepared in Example 1 can effectively suppress side reactions, which is conducive to the uniform deposition / dissolution of zinc ions and extends the battery cycle life.

[0063] See Figure 5 The symmetrical cells assembled in Example 1 and Comparative Examples 1-2 were tested at 1 mA·cm⁻¹. -2 1 mAh•cm -2 and 5 mA•cm -2 5 mAh•cm -2 The cycling performance graph below shows that at 1 mA•cm -2 1 mAh•cm -2 The cycle lives of the symmetrical cells assembled in Example 1 and Comparative Examples 1-2 were 3600 h, 400 h, and 200 h, respectively, with Example 1 showing an improvement in cycle life exceeding 3000 h; at 5 mA•cm -2 5 mAh•cm -2 The cycle life of the symmetrical cells assembled in Example 1 and Comparative Examples 1-2 were 2800h, 80h and 100h, respectively, showing a significant improvement in cycle life.

[0064] Performance verification showed that the electrolyte with added isopropanol in Comparative Example 2 did not have a significant modification effect, therefore the following experiments will not be discussed.

[0065] See Figure 6 The symmetrical cells assembled in Example 1 and Comparative Example 1 were tested at 1 mA·cm⁻¹. -2 1 mAh•cm -2 The SEM cross-sectional image magnified 500 times after 10 cycles clearly shows that after the addition of cyclopropanol, zinc ions are deposited evenly and the surface is smooth and flat, while Comparative Example 1 has a large number of dendrites.

[0066] See Figure 7 The symmetrical cells assembled in Example 1 and Comparative Example 1, at 1 mA•cm -2 1 mAh•cm -2 The SEM images of the front side after 10 cycles, magnified 500 to 5000 times, clearly show the overall flatness of Example 1, while Comparative Example 1 has a large number of dendrites.

[0067] See Figure 8 In situ optical microscopy tests on the symmetrical cells assembled in Example 1 and Comparative Example 1 also revealed that zinc ions were uniformly deposited in Example 1 during the electrochemical process, while a large number of dendrites were formed in Comparative Example 1.

[0068] See Figure 9 The in-situ pH values ​​of the symmetrical cells assembled in Example 1 and Comparative Example 1 show that the pH increase in Example 1 is smaller than that in Comparative Example 1 during the electrochemical process, indicating that the hydrogen evolution side reaction in Example 1 is less severe.

[0069] See Figure 10The cycling performance diagrams of the zinc-manganese full cells assembled in Example 1 and Comparative Example 1 show that, during 100 cycles, the capacity of Example 1 is significantly higher than that of Comparative Example 1, indicating that the cyclopropanol additive has no negative impact on the cathode material and may even have a certain positive effect.

[0070] Test case

[0071] Artificial seawater was used as the solvent for the electrolyte in Example 1 and Comparative Example 1. See [link to relevant documentation]. Figure 11 The symmetrical cells assembled in Example 1 and Comparative Example 1 were tested at 1 mA·cm⁻¹. -2 1 mAh•cm -2 The cycle lives were 50h and 2200h, respectively, indicating that the cyclopropanol additive in Example 1 still has good electrochemical performance under more demanding conditions.

[0072] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. The application of an organic small molecule electrolyte additive in the preparation of zinc metal battery electrolyte, characterized in that, The organic small molecule electrolyte additive is a small molecule alcohol containing a carbon three-membered ring; the small molecule alcohol containing a carbon three-membered ring is cyclopropanol; the content of the organic small molecule electrolyte additive is 1%-10% v / v; The zinc metal battery electrolyte includes the solute ZnSO4, the solvent, and the organic small molecule electrolyte additive. The solvent is deionized water or artificial seawater.

2. The application as described in claim 1, characterized in that, The concentration of the solute in the zinc metal battery electrolyte is 1-4 mol / L.

3. The application as described in claim 1, characterized in that, The solvent content in the zinc metal battery electrolyte is 41.2%-85.3% v / v.

4. The application as described in claim 1, characterized in that, The artificial seawater contained sodium ions at 107216.48 ppm, magnesium ions at 1416.88 ppm, potassium ions at 399.01 ppm, calcium ions at 407.43 ppm, chloride ions at 19939.54 ppm, bromide ions at 56.22 ppm, and sulfate ions at 2644.59 ppm.

5. The application as described in claim 1, characterized in that, The method for preparing the zinc metal battery electrolyte is as follows: add the solute to the solvent to prepare a mixture, then add the additives, shake and stir, and ultrasonically mix evenly to obtain the electrolyte.

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