A low-eutectic solvent high-entropy electrolyte and its application

Abstract

This invention relates to the field of electrochemical energy storage technology, and in particular to a novel high-entropy electrolyte based on a eutectic solvent and its application in electrochemical devices such as low-temperature secondary batteries and supercapacitors. The eutectic solvent high-entropy electrolyte of this invention is composed of at least five eutectic solvents; each eutectic solvent consists of a hydrogen bond acceptor and a hydrogen bond donor; the hydrogen bond acceptor is one of choline chloride, tetraethylammonium chloride, tetrabutylammonium chloride, zinc chloride, magnesium chloride, lithium perchlorate, and water; the hydrogen bond donor is one of urea, citric acid, lactic acid, acrylic acid, itaconic acid, formic acid, ethylene glycol, glycerol, acetamide, formamide, and water. The eutectic solvent high-entropy electrolyte of this invention not only lowers the liquid-solid transition temperature of the electrolyte, achieving better low-temperature performance, but also has the advantages of low raw material cost and environmental friendliness.

Description

Technical Field

[0001] This invention relates to the field of electrochemical energy storage technology, and in particular to a novel high-entropy electrolyte based on a low eutectic solvent and its application in electrochemical devices such as low-temperature secondary batteries and supercapacitors. Background Technology

[0002] Low-temperature environments (typically below -20°C) pose severe challenges to the performance of electrochemical energy storage devices. The electrolyte, as the core medium for ion transport, directly determines the reliability of batteries or capacitors based on its low-temperature adaptability. Traditional electrolytes (such as organic carbonate electrolytes and aqueous electrolytes) are widely used in electrochemical devices, but they suffer from poor low-temperature performance. At low temperatures, the thermal motion of electrolyte solvent molecules weakens, leading to an exponential increase in viscosity or freezing, and a sharp drop in ionic conductivity, thus degrading the performance of electrochemical devices.

[0003] Eutectic solvents are green solvents composed of hydrogen bond donors and acceptors, offering advantages such as low cost, low toxicity, high stability, and adjustability. However, existing eutectic solvent electrolytes for electrochemical devices still face challenges such as low ionic conductivity and poor low-temperature performance. This invention aims to provide a novel high-entropy eutectic solvent electrolyte that utilizes the configurational entropy increase effect to lower the liquid-solid transition temperature, thereby solving the aforementioned problems and improving the performance of electrochemical devices. Summary of the Invention

[0004] Based on the above, the present invention provides a low eutectic solvent high entropy electrolyte, which improves the entropy value of the electrolyte system to achieve low temperature resistance, enabling low eutectic solvent electrochemical devices to operate normally at low temperatures.

[0005] To achieve the above objectives, the present invention provides the following solution:

[0006] One of the technical solutions of the present invention is a low eutectic solvent high entropy electrolyte, which is composed of at least five low eutectic solvents;

[0007] The eutectic solvent consists of hydrogen bond acceptors and hydrogen bond donors;

[0008] The hydrogen bond acceptor is one of choline chloride, tetraethylammonium chloride, tetrabutylammonium chloride, zinc chloride, magnesium chloride, lithium perchlorate, and water;

[0009] The hydrogen bond donor is one of urea, citric acid, lactic acid, acrylic acid, itaconic acid, formic acid, ethylene glycol, glycerol, acetamide, formamide, and water.

[0010] The second technical solution of the present invention is the application of the above-mentioned low eutectic solvent high entropy electrolyte in electrochemical devices.

[0011] The third technical solution of the present invention is a supercapacitor, comprising electrode materials, a separator, and the aforementioned eutectic solvent high-entropy electrolyte.

[0012] The fourth technical solution of the present invention is a low-temperature secondary battery, comprising a positive electrode material, a negative electrode material, a separator, and the aforementioned eutectic solvent high-entropy electrolyte.

[0013] The present invention discloses the following technical effects:

[0014] The low eutectic solvent high entropy electrolyte of the present invention not only reduces the liquid-solid transition temperature of the electrolyte and can obtain better low-temperature performance, but also has the advantages of low raw material cost and green environmental protection.

[0015] The low eutectic solvent high entropy electrolyte of the present invention has a wide electrochemical window and excellent low-temperature performance, and is suitable for electrochemical devices such as secondary batteries and supercapacitors, which can improve their cycle life, energy density and safety. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 Differential scanning calorimetry curve of the low eutectic solvent high entropy electrolyte prepared in Example 1.

[0018] Figure 2 The cyclic voltammetry curves of the supercapacitor using the eutectic solvent high-entropy electrolyte prepared in Example 3 at 25°C are shown.

[0019] Figure 3 The cyclic voltammetry curves of the supercapacitor using the eutectic solvent high-entropy electrolyte prepared in Example 3 at -50°C are shown. Detailed Implementation

[0020] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0021] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0022] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0023] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0024] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0025] The first aspect of this invention provides a eutectic solvent high-entropy electrolyte, composed of at least five eutectic solvents;

[0026] The eutectic solvent consists of hydrogen bond acceptors and hydrogen bond donors;

[0027] The hydrogen bond acceptor is one of choline chloride, tetraethylammonium chloride, tetrabutylammonium chloride, zinc chloride, magnesium chloride, lithium perchlorate, and water;

[0028] The hydrogen bond donor is one of urea, citric acid, lactic acid, acrylic acid, itaconic acid, formic acid, ethylene glycol, glycerol, acetamide, formamide, and water.

[0029] In a preferred embodiment of the present invention, the molar ratio of the hydrogen bond acceptor to the hydrogen bond donor is 1:(0.25-6).

[0030] In a further preferred embodiment of the present invention, the molar ratio of the hydrogen bond acceptor to the hydrogen bond donor is 1:(2-4).

[0031] In a further preferred embodiment of the present invention, the eutectic solvent high-entropy electrolyte is composed of five eutectic solvents; the volume fraction of the five eutectic solvents in the eutectic solvent high-entropy electrolyte is independently 5% to 95%.

[0032] In a further preferred embodiment of the present invention, the eutectic solvent high-entropy electrolyte is composed of five eutectic solvents in a volume ratio of 1:1:1:1:1.

[0033] The low eutectic solvent high entropy electrolyte of the present invention can be applied in low temperature environments of -60°C.

[0034] The second aspect of the present invention provides the application of the above-mentioned low eutectic solvent high entropy electrolyte in electrochemical devices.

[0035] A third aspect of the present invention provides a supercapacitor comprising an electrode material, a glass fiber diaphragm, and the aforementioned eutectic solvent high-entropy electrolyte.

[0036] The supercapacitor is an activated carbon-activated carbon supercapacitor.

[0037] A fourth aspect of the present invention provides a low-temperature secondary battery, comprising a positive electrode material, a negative electrode material, a glass fiber separator, and the aforementioned eutectic solvent high-entropy electrolyte.

[0038] Unless otherwise specified, the technical solutions described in this invention are all conventional solutions in the field, and the reagents or raw materials used are all purchased from commercial channels or are publicly available unless otherwise specified.

[0039] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0040] Example 1

[0041] Choline chloride was mixed with formic acid, ethylene glycol, glycerol, urea, and acetamide in a molar ratio of 1:2 to prepare five eutectic solvents. These five eutectic solvents were then mixed in a volume ratio of 1:1:1:1:1 and stirred until homogeneous at room temperature to obtain a high-entropy electrolyte with a liquid-solid transition temperature below -60°C. Figure 1 (As shown).

[0042] Example 2

[0043] Choline chloride, tetraethylammonium chloride, tetrabutylammonium chloride, zinc chloride, and lithium perchlorate were each mixed with ethylene glycol in a molar ratio of 1:4 to prepare five eutectic solvents. These five eutectic solvents were then mixed in a volume ratio of 1:1:1:1:1 and stirred until homogeneous at room temperature to obtain a high-entropy eutectic solvent electrolyte with a liquid-solid transition temperature below -60°C.

[0044] Example 3

[0045] Choline chloride, tetraethylammonium chloride, and tetrabutylammonium chloride were each mixed with glycerol in a molar ratio of 1:3 to prepare three eutectic solvents; magnesium chloride and lithium perchlorate were each mixed with water in a molar ratio of 1:2 to prepare two eutectic solvents. Then, the above five eutectic solvents were mixed in a volume ratio of 1:1:1:1:1 and stirred evenly at room temperature to obtain a high-entropy eutectic solvent electrolyte with a liquid-solid transition temperature of -60℃.

[0046] The eutectic solvent high-entropy electrolyte prepared in this embodiment was used in a eutectic solvent supercapacitor (structure: composed of activated carbon negative electrode, activated carbon positive electrode, glass fiber diaphragm, and eutectic solvent high-entropy electrolyte). The test conditions were 10 mV / s and 25 °C. The cyclic voltammetry curve is shown below. Figure 2 As shown, by Figure 2 It can be seen that the eutectic solvent high-entropy electrolyte prepared in Example 3 allows it to operate within a 1.2V voltage window, which is at least 20% higher than the voltage window of commonly used supercapacitors composed of activated carbon in potassium hydroxide aqueous solution, which is no higher than 1.0V. Meanwhile, the cyclic voltammetry curve area obtained by this supercapacitor at -50℃ ( Figure 3 Although it is more than Figure 2 The cyclic voltammetry curve at 25℃ has a small area but still retains an olive shape, indicating that the prepared eutectic solvent high-entropy electrolyte endows the supercapacitor with good reversibility at low temperatures.

[0047] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. The application of a low-eutectic solvent high-entropy electrolyte in electrochemical devices, characterized in that, The eutectic solvent high-entropy electrolyte is composed of five eutectic solvents in a volume ratio of 1:1:1:1:1; The eutectic solvent consists of hydrogen bond acceptors and hydrogen bond donors; The preparation method of the low eutectic solvent high entropy electrolyte is either Method 1 or Method 2; The steps of method one are as follows: Choline chloride, tetraethylammonium chloride, tetrabutylammonium chloride, zinc chloride, and lithium perchlorate were respectively mixed with ethylene glycol in a molar ratio of 1:4 to prepare five eutectic solvents; then the above five eutectic solvents were mixed in a volume ratio of 1:1:1:1:1 and stirred evenly at room temperature to obtain a eutectic solvent high-entropy electrolyte. The steps of method two are as follows: Choline chloride, tetraethylammonium chloride, and tetrabutylammonium chloride were mixed with glycerol in a molar ratio of 1:3 to prepare three eutectic solvents; magnesium chloride and lithium perchlorate were mixed with water in a molar ratio of 1:2 to prepare two eutectic solvents; then the above five eutectic solvents were mixed in a volume ratio of 1:1:1:1:1 and stirred evenly at room temperature to obtain a high-entropy electrolyte with eutectic solvent.

2. The application according to claim 1, characterized in that, The electrochemical device is a supercapacitor, comprising electrode materials, a separator, and a low-eutectic solvent high-entropy electrolyte.

3. The application according to claim 1, characterized in that, The electrochemical device is a low-temperature secondary battery, comprising a positive electrode material, a negative electrode material, a separator, and a low eutectic solvent high-entropy electrolyte.

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