Halogenate and phosphate composite electrolyte for rechargeable magnesium battery and preparation method and application of halide and phosphate composite electrolyte

Abstract

The invention discloses a halide and phosphate composite electrolyte for a rechargeable magnesium battery as well as a preparation method and application of the halide and phosphate composite electrolyte, and belongs to the technical field of new energy battery preparation. The halide and phosphate composite electrolyte for the rechargeable magnesium battery comprises an electrolyte salt, an organic ether solvent, a phosphate cosolvent and a halide additive. By introducing the halide additive into the organic magnesium salt electrolyte, the solvation structure of magnesium ions in the electrolyte is optimized and regulated, the problem that magnesium metal is extremely easy to passivate is solved, a stable magnesium ion solid electrolyte conducting layer is formed on the surface of the magnesium metal, the conductivity of the magnesium ions is improved, and side reaction between a magnesium negative electrode and the electrolyte is reduced. Meanwhile, the phosphate cosolvent is introduced, so that the corrosivity of the composite electrolyte is reduced, the electrochemical polarization energy barrier is further reduced, and the reversibility and oxidation stability of the rechargeable magnesium battery are improved. The preparation method of the composite electrolyte is simple and easy for large-scale production.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of new energy batteries, and particularly relates to a halide and phosphate ester composite electrolyte for a rechargeable magnesium battery and a preparation method and application thereof. BACKGROUND

[0002] Rechargeable lithium-ion batteries have revolutionized the mobile device industry and are increasingly gaining attention in the development of electric vehicles and grid storage applications. However, due to the scarcity and high cost of lithium resources, people need to explore more sustainable battery materials. Rechargeable magnesium-ion batteries (rechargeable magnesium batteries) stand out because magnesium metal has several inherent advantages: extremely abundant reserves (more than a thousand times that of lithium), high theoretical volume capacity of 3833 mAh / cm3 (~1.8 times that of lithium metal 2061 mAh / cm3), and a lower redox potential (−2.37 V vs. standard hydrogen electrode). More importantly, magnesium metal naturally has anti-dendrite growth characteristics, providing a higher safety factor compared to lithium, sodium, potassium, and other metal anodes. Unfortunately, the practical application of rechargeable magnesium batteries in commercial electrolyte systems has encountered major obstacles. The magnesium anode has a high overpotential in this system, leading to a sharp decline in performance, which is mainly due to surface passivation and slow interfacial electrochemical kinetics. The high mass-to-charge ratio of Mg 2+ forms a strong coordination bond with ether solvents, significantly increasing the solvent desorption energy barrier. This greatly hinders the transport of Mg 2+ , and leads to a high charging overpotential. Therefore, the lack of electrolyte is still a key challenge in building high-energy-density rechargeable magnesium batteries. There are few traditional electrolytes that can simultaneously meet the wide electrochemical window and reversibly dissolve-deposit magnesium metal.

[0003] In summary, these challenges greatly hinder the development of rechargeable magnesium batteries. SUMMARY

[0004] In order to solve the problems of low ionic conductivity, low coulombic efficiency, limited electrochemical window, and compatibility with electrodes of existing rechargeable magnesium battery electrolytes, the application provides a halide and phosphate ester composite electrolyte for a rechargeable magnesium battery and a preparation method and application thereof. The halide and phosphate ester composite electrolyte for a rechargeable magnesium battery provided by the application is a composite electrolyte with high ionic conductivity, high magnesium metal dissolution-deposition efficiency, high electrochemical window, and the ability to match more positive electrodes.

[0005] To achieve the above-mentioned purpose, the application provides the following technical solutions:

[0006] The application provides a halide and phosphate ester composite electrolyte for a rechargeable magnesium battery, which comprises an electrolyte salt, an organic ether solvent, a phosphate ester co-solvent, and a halide additive.

[0007] The electrolyte salt is an organic magnesium salt.

[0008] The mechanism of the present application: by adding halide additive and phosphate co-solvent into the traditional organic magnesium salt-ether electrolyte, this double regulation method not only expands the electrochemical stability window to 3.94 V, but also optimizes the solvation structure to reduce the desolvation energy barrier. In the traditional electrolyte, Mg 2+ It is difficult to desolvate, resulting in high overpotential, rapid performance decay and poor electrochemical window. In the present application, during the preferential reduction of the halide additive, the halide additive and the phosphate co-solvent promote the inorganic-rich solid interface phase, which exhibits extremely high ionic conductivity and inhibits the interface side reaction. At the same time, the phosphate co-solvent can effectively alleviate the acidification and corrosion of the electrolyte by the halide additive.

[0009] Further, the organic magnesium salt is selected from one of magnesium bis(trifluoromethylsulfonyl)imide, magnesium trifluoromethanesulfonate, chlorine-containing complex magnesium salt and magnesium tetra(hexafluoroisopropoxyborate).

[0010] Further, the organic ether solvent is selected from at least one of tetrahydrofuran, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether and 2-methyltetrahydrofuran.

[0011] Further, the phosphate co-solvent is selected from one of trimethyl phosphate, triethyl phosphate, tripropyl phosphate and tris(trimethylsilyl) phosphate.

[0012] Further, the halide additive is selected from one of magnesium chloride, silicon chloride, silicon bromide, antimony bromide, tin bromide and boron bromide.

[0013] Further, the molar concentration of the electrolyte salt in the halide-phosphate composite electrolyte for rechargeable magnesium batteries is 0.1-1.0 M.

[0014] Further, the molar concentration of the halide additive in the halide-phosphate composite electrolyte for rechargeable magnesium batteries is 0.2-0.5 M.

[0015] The present application also provides a preparation method of the above-mentioned halide-phosphate composite electrolyte for rechargeable magnesium batteries, comprising the following steps: adding an electrolyte salt into a mixed solvent composed of an organic ether solvent and a phosphate co-solvent, stirring uniformly, adding a halide additive, stirring again, to obtain the halide-phosphate composite electrolyte for rechargeable magnesium batteries.

[0016] The present application also provides a rechargeable magnesium battery, whose electrolyte is the above-mentioned halide-phosphate composite electrolyte for rechargeable magnesium batteries.

[0017] The application also provides application of the halide and phosphate ester composite electrolyte for the rechargeable magnesium battery in preparation of the rechargeable magnesium battery.

[0018] Compared with the prior art, the application has the following advantages and technical effects:

[0019] The application introduces the halide additive into the organic magnesium salt electrolyte, optimizes the solvation structure of magnesium ions in the electrolyte and the easy passivation problem of the magnesium metal, forms a stable magnesium ion solid electrolyte conductive layer on the magnesium metal surface, improves the magnesium ion conductivity and reduces the side reaction between the magnesium negative electrode and the electrolyte. Meanwhile, the introduction of the phosphate ester cosolvent reduces the corrosiveness of the composite electrolyte, further reduces the electrochemical polarization energy barrier, improves the reversibility and oxidation stability of the rechargeable magnesium battery. The preparation method of the composite electrolyte is simple and easy for large-scale production. BRIEF DESCRIPTION OF DRAWINGS

[0020] The accompanying drawings, which form a part of the present application, are used to provide further understanding of the present application, and serve as an aid in explaining the exemplary embodiments of the present application and their descriptions, and do not constitute improper limitations on the present application. In the drawings:

[0021] Figure 1 The photo images of the composite electrolytes prepared in Example 10-Example 15, Comparative Example 2-7 and the XRD images of the magnesium sheets after the magnesium sheets are soaked for 30 minutes are shown, wherein (a) is Example 10 (left) and Comparative Example 2 (right), (b) is Example 11 (left) and Comparative Example 3 (right), (c) is Example 12 (left) and Comparative Example 4 (right), (d) is Example 13 (left) and Comparative Example 5 (right), (e) is Example 14 (left) and Comparative Example 6 (right), and (f) is Example 15 (left) and Comparative Example 7 (right).

[0022] Figure 2 The Tafel curve diagram of the composite electrolytes prepared in Example 1, Comparative Example 1 and Comparative Example 4 is shown.

[0023] Figure 3 The linear voltammetry test curve diagram of the composite electrolytes prepared in Example 1 (right) and Comparative Example 4 (left) is shown.

[0024] Figure 4 The charge-discharge curve and cycle stability of the magnesium negative electrode in the composite electrolytes prepared in Example 1, Comparative Example 1 and Comparative Example 4 (the constant current charge-discharge current density is 0.1 mA·cm -2 , and the constant area capacity is 0.1 mAh·cm -2 ).

[0025] Figure 5Charge-discharge curves and cycle stability of magnesium negative electrode in composite electrolyte prepared in Example 2-9 (constant area capacity is 0.1 mAh cm -2 , constant current charge-discharge current density is 0.1 mA cm -2 ).

[0026] Figure 6 Charge-discharge curves and cycle stability of magnesium negative electrode in composite electrolyte prepared in Example 1, Comparative Example 1 and Comparative Example 4 (constant area capacity is 0.5 mAh cm -2 , constant current charge-discharge current density is 0.5 mA cm -2 ).

[0027] Figure 7 Charge-discharge curves and cycle stability of magnesium negative electrode in composite electrolyte prepared in Example 25 (constant area capacity is 0.1 mAh cm -2 , constant current charge-discharge current density is 0.1 mA cm -2 ).

[0028] Figure 8 Rate polarization performance curves of composite electrolyte prepared in Example 1, Comparative Example 1 and Comparative Example 4 in Mg||Mg symmetric cell at different current densities (constant area capacity is 0.1 mAh cm -2 ).

[0029] Figure 9 Rate polarization performance curves of composite electrolyte prepared in Example 16-24 in Mg||Mg symmetric cell at different current densities (constant area capacity is 0.1 mAh cm -2 ).

[0030] Figure 10 Nyquist plots (EIS) of composite electrolyte prepared in Example 1, Comparative Example 1 and Comparative Example 4 in Mg||Mo asymmetric cell after different cycles of magnesium metal dissolution / deposition electrochemical test, wherein (a) is Comparative Example 1, (b) is Comparative Example 4, (c) is Example 1.

[0031] Figure 11 Charge-discharge curves and cycle stability of composite electrolyte prepared in Example 1, Comparative Example 1 and Comparative Example 4 in Mg||Mo asymmetric cell composed of Mo electrode and magnesium electrode at different cut-off voltages.

[0032] Figure 12 Cycle performance, charge-discharge curves and coulombic efficiency of composite electrolyte prepared in Example 1 in Mg||Mo asymmetric cell composed of Mo electrode and magnesium electrode at cut-off voltage of 3.4 V, wherein (a) is cycle performance, (b) is coulombic efficiency, (c) is charge-discharge curves.

[0033] Figure 13 SEM images (scale bar 50 pm) of the composite electrolyte prepared for Example 1, Comparative Example 1 and Comparative Example 4 after 200 h of magnesium metal dissolution / deposition electrochemical test, where (a) is Comparative Example 1, (b) is Comparative Example 4, and (c) is Example 1;

[0034] Figure 14 Cycle performance plots of the composite electrolyte prepared for Example 1, Comparative Example 1 and Comparative Example 4 at different rates in Mg || Mo6S8 full cell;

[0035] Figure 15 Cycle performance plots of the composite electrolyte prepared for Example 1 and Comparative Example 4 at 0.5 C rate in Mg || Mo6S8 full cell;

[0036] Figure 16 Cycle performance plot of the composite electrolyte prepared for Example 1 at 0.5 C rate in Mg || PANI-V2O5 full cell. DETAILED DESCRIPTION

[0037] Various illustrative embodiments of the present application are now described in detail below. The description made herein is not to be construed as limiting the present application, but rather as providing certain examples of the present application. The examples described herein should not be construed as limiting the present application, but rather as providing certain examples of the present application.

[0038] It should be understood that the terms used herein are for the purpose of describing particular embodiments and are not intended to limit the present application. Additionally, for numerical ranges that are expressed in a range format, it is intended that any and every set of numbers within that range (e.g. one through ten) and in between (e.g. one through five.1 through 5.5) are contemplated. The same applies to ranges that are expressed in terms of "between". It is also intended that every conceivable number or element that such a range would include is explicitly contemplated. The same is true for any numerical ranges expressed in terms of maximum and minimum values. Accordingly, the phrase "between x and y" should be understood to include the range of values from x to y, as well as the individual values x and y. The same applies to ranges that are expressed in terms of "between".

[0039] 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 application belongs. Although preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application. All documents mentioned herein are incorporated by reference to disclose and describe the methods and / or materials in connection with which the documents are cited. In case of conflict between the content of the specification and that of any document incorporated herein by reference, the content of the specification prevails.

[0040] 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 readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0041] 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.

[0042] Embodiments of the present invention provide a halogenated and phosphate ester composite electrolyte for rechargeable magnesium batteries, comprising an electrolyte salt, an organic ether solvent, a phosphate ester co-solvent, and a halogenated additive;

[0043] The electrolyte salt is an organic magnesium salt.

[0044] In the halogenated compound electrolyte and phosphate ester composite electrolyte for rechargeable magnesium batteries of the present invention, the following interactions exist:

[0045] 1. Halogenated additives interact with organic ether solvents: Halogenated additives can weaken the interaction between organic ether solvents and Mg. 2+ The interaction allows more anions to incorporate into the solvation shell, thus benefiting Mg. 2+ Dissociation.

[0046] 2. Interactions exist between phosphate ester cosolvents and organic ether solvents: Phosphate ester cosolvents and organic ether solvents exhibit strong interactions at the molecular level. Due to the high dielectric constant of phosphate ester cosolvents, they can synergistically interact with the polar portions of the solvent molecules, thereby altering the solvation structure of magnesium ions. This interaction helps increase the solubility of magnesium ions in the solvent, making them more readily migrate to the electrode surface, improving the conductivity of the electrolyte, reducing overpotential, and thus enhancing battery performance.

[0047] 3. Interaction between halogenated additives and electrode surfaces: The introduction of halogenated additives not only allows them to be preferentially reduced on the magnesium metal anode surface, thereby promoting the formation of a highly conductive inorganic solid electrolyte conductive layer, but also allows the halogenated additives to preferentially adsorb, effectively preventing magnesium metal from directly contacting ether solvents, thereby further reducing solvent decomposition and side reactions.

[0048] 4. The interaction between phosphate co-solvent and electrode surface: The phosphate co-solvent interacts with the surface of the magnesium metal anode during the operation of the battery, promoting the formation of a stable protective solid-state electrolyte interphase on the electrode surface. This layer not only helps to improve the deposition efficiency of magnesium ions, but also reduces the adverse reactions between the electrolyte and the metal anode and protects the inorganic solid-state electrolyte interphase formed by the introduced halide additive, thereby maintaining the high cycle performance of the battery.

[0049] 5. The effect of phosphate co-solvent and halide additive on the electrochemical polarization of the electrolyte: The addition of phosphate co-solvent and halide additive reduces the electrochemical polarization energy barrier of the electrolyte during the charging and discharging process of the battery. This effect helps to improve the deposition-dissolution efficiency of magnesium metal, while reducing the overpotential of the battery, and has excellent rate performance.

[0050] In summary, the role of phosphate co-solvent and halide additive in the composite electrolyte of the present application not only includes improving the conductivity of the electrolyte and reducing the overpotential, but also includes the interaction with organic ether solvents, which enhances the stability and electrochemical performance of the composite electrolyte. Through this interaction, the phosphate co-solvent and halide additive help to increase the coordination number of magnesium ions and anions, promote the deposition-dissolution process of magnesium metal, improve the coulombic efficiency, reduce the side reactions and passivation film formation of the composite electrolyte, and in-situ form a more advantageous solid-state electrolyte interphase, thereby providing a guarantee for the high rate and long cycle stability of the battery.

[0051] In the embodiments of the present application, the organic magnesium salt is selected from one of bis(trifluoromethylsulfonyl)imide magnesium, magnesium triflate, chlorine-containing complex magnesium salt, and magnesium tetra(hexafluoroisopropoxyborate), preferably bis(trifluoromethylsulfonyl)imide magnesium as the source of magnesium ions in the electrolyte. Compared with other common magnesium salts, bis(trifluoromethylsulfonyl)imide magnesium has higher solubility, low cost, and simple synthesis steps.

[0052] When bis(trifluoromethylsulfonyl)imide magnesium is used as a single magnesium salt, the electrolyte is prepared by using phosphate esters as a co-solvent to dissolve the magnesium salt, while adding a halide additive, without additional additives and water removal agents, solving the corrosion problem of bis(trifluoromethylsulfonyl)imide magnesium in ether solvents, effectively inhibiting the passivation phenomenon on the surface of the magnesium metal negative electrode, and significantly improving the transmission efficiency of magnesium ions and the interface reaction kinetics. Experimental data show that the symmetrical battery using the composite electrolyte of the application achieves stable cycling for 1800 hours, and the overpotential is as low as 0.14 volts. The non-symmetrical battery has a reversible charge-discharge coulomb efficiency of 99.97% at a voltage of 3.4 volts. In addition, the vanadium pentoxide full battery can provide a reversible capacity of 160 milliampere hours per gram at a voltage of 2.6 volts, and the hexamolybdenum octasulfide full battery has excellent rate performance. The application opens up a feasible way for the preparation of high-performance magnesium ion batteries (especially rechargeable magnesium batteries).

[0053] In the embodiments of the application, the organic ether solvent is selected from at least one of tetrahydrofuran, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether and 2-methyltetrahydrofuran, and is preferably ethylene glycol dimethyl ether.

[0054] In the embodiments of the application, the phosphate ester co-solvent is selected from one of trimethyl phosphate, triethyl phosphate, tripropyl phosphate and tris(trimethylsilyl) phosphate.

[0055] In the embodiments of the application, the halide additive is selected from one of magnesium chloride, silicon chloride, silicon bromide, antimony bromide, tin bromide and boron bromide.

[0056] In the embodiments of the application, the molar concentration of the electrolyte salt in the halide and phosphate composite electrolyte for the rechargeable magnesium battery is 0.1-1.0 M, and is preferably 0.3-0.5 M.

[0057] In the embodiments of the application, the molar concentration of the halide additive in the halide and phosphate composite electrolyte for the rechargeable magnesium battery is 0.2-0.5 M, and is preferably 0.35 M.

[0058] The embodiments of the application also provide a preparation method of the above-mentioned halide and phosphate composite electrolyte for the rechargeable magnesium battery, which comprises the following steps: adding an electrolyte salt into a mixed solvent composed of an organic ether solvent and a phosphate ester co-solvent, stirring uniformly, adding a halide additive, stirring again, and obtaining the halide and phosphate composite electrolyte for the rechargeable magnesium battery.

[0059] The embodiments of the application also provide a rechargeable magnesium battery, and the electrolyte of the rechargeable magnesium battery is the above-mentioned halide and phosphate composite electrolyte for the rechargeable magnesium battery.

[0060] The embodiment of the present application also provides application of the halide and phosphate ester composite electrolyte for the rechargeable magnesium battery in preparation of the rechargeable magnesium battery.

[0061] In the following embodiments and comparative examples of the present application, the battery performance test is performed by using a new battery test system and a biologic electrochemical workstation, and the physical property characterization is performed by using a scanning electron microscope and an X-ray diffractometer. In order to test the electrochemical performance of the electrolyte, the Mg||Mg symmetric battery, the asymmetric battery (including Mg||Al, Mg||Cu, Mg||Mo, Mg||SS) and the full battery (including Mg||Mo6S8, Mg||PANI-V2O5) are respectively used, the electrolyte prepared in each of the following embodiments and comparative examples is used, the separator is a glass fiber, and a CR2025 button cell is assembled to perform the magnesium metal dissolution / deposition, the electrochemical impedance spectroscopy, the linear sweep voltammetry, the full battery cycle and other tests.

[0062] In the embodiment of the present application, the molecular sieve is 4 ℃ molecular sieve purchased from Dongguan Keluode New Energy Technology Co., Ltd., and the model number is MA-CM-OT-005001 (4 ℃ molecular sieve, which is spherical with a diameter of Φ3-5 mm).

[0063] Unless otherwise specified, the room temperature in the present application is 30±2℃.

[0064] Each raw material used in the embodiment of the present application is commercially available.

[0065] The technical solutions of the present application are further described through the following embodiments.

[0066] Embodiment 1

[0067] The halide and phosphate ester composite electrolyte for the rechargeable magnesium battery provided in the embodiment comprises the following substances: magnesium bis(trifluoromethylsulfonyl) imide (as an electrolyte salt), ethylene glycol dimethyl ether (as an organic ether solvent), tris(trimethylsilyl) phosphate ester (as a phosphate ester cosolvent) and silicon bromide (as a halide additive), the volume ratio of ethylene glycol dimethyl ether (DME) to tris(trimethylsilyl) phosphate ester (TMSP) is 85:15, the molar concentration of magnesium bis(trifluoromethylsulfonyl) imide (Mg(TFSI)2) in the composite electrolyte is 0.5M, and the molar concentration of silicon bromide (SiBr4) in the composite electrolyte is 0.35M.

[0068] The preparation method of the halide and phosphate ester composite electrolyte for rechargeable magnesium battery is as follows: in an argon glove box with water and oxygen contents less than 0.1 ppm, 0.438 g of magnesium bis(trifluoromethylsulfonyl)imide is weighed and added to 1.5 mL of a mixed solvent of ethylene glycol dimethyl ether and tris(trimethylsilyl) phosphate (the volume ratio of ethylene glycol dimethyl ether to tris(trimethylsilyl) phosphate is 85:15), and magnetically stirred at a stirring speed of 600 r / min and a temperature of 30°C for 10 minutes to ensure that the magnesium bis(trifluoromethylsulfonyl)imide is uniformly dispersed in the mixed solvent of ethylene glycol dimethyl ether and tris(trimethylsilyl) phosphate; then 0.18 g of silicon bromide is added to the above mixture using a pipette, and magnetically stirred at a stirring speed of 600 r / min and a temperature of 30°C for 10 minutes; after the reaction is completed, a colorless, clear and transparent halide and phosphate ester composite electrolyte for rechargeable magnesium battery, i.e., 0.5M Mg(TFSI)2 + 0.35M SiBr4 in DME:TMSP (v:v=85:15) composite electrolyte, is obtained.

[0069] Example 2

[0070] The halide and phosphate ester composite electrolyte for rechargeable magnesium battery provided in this example is composed of magnesium bis(trifluoromethylsulfonyl)imide (as an electrolyte salt), ethylene glycol dimethyl ether (as an organic ether solvent), tris(trimethylsilyl) phosphate (as a phosphate ester cosolvent), and silicon bromide (as a halide additive), the volume ratio of ethylene glycol dimethyl ether to tris(trimethylsilyl) phosphate is 90:10, the molar concentration of magnesium bis(trifluoromethylsulfonyl)imide in the composite electrolyte is 0.5M, and the molar concentration of silicon bromide in the composite electrolyte is 0.35M.

[0071] The preparation method of the halide and phosphate composite electrolyte for the rechargeable magnesium battery comprises the following steps: in an argon glove box with water and oxygen contents less than 0.1 ppm, 0.438 g of magnesium bis(trifluoromethylsulfonyl)imide is weighed and added into 1.5 mL of a mixed solvent of ethylene glycol dimethyl ether and tris(trimethylsilyl) phosphate (the volume ratio of ethylene glycol dimethyl ether to tris(trimethylsilyl) phosphate is 90:10), and then the mixture is magnetically stirred at a stirring speed of 600 r / min and a temperature of 30°C for 10 min to ensure that the magnesium bis(trifluoromethylsulfonyl)imide is uniformly dispersed in the mixed solvent of ethylene glycol dimethyl ether and tris(trimethylsilyl) phosphate; then, 0.18 g of silicon bromide is taken by using a pipette and added into the above mixture, and the mixture is magnetically stirred at a stirring speed of 600 r / min and a temperature of 30°C for 10 min, and after sufficient reaction, a colorless, clear and transparent composite electrolyte, namely, 0.5M Mg(TFSI)2 + 0.35M SiBr4 in DME:TMSP (v:v=80:20) composite electrolyte, is obtained.

[0072] Example 3

[0073] The halide and phosphate composite electrolyte for the rechargeable magnesium battery provided by the example comprises the following substances: magnesium bis(trifluoromethylsulfonyl)imide (as an electrolyte salt), ethylene glycol dimethyl ether (as an organic ether solvent), tris(trimethylsilyl) phosphate (as a phosphate co-solvent) and silicon bromide (as a halide additive), the volume ratio of ethylene glycol dimethyl ether to tris(trimethylsilyl) phosphate is 95:5, the molar concentration of magnesium bis(trifluoromethylsulfonyl)imide in the composite electrolyte is 0.5M, and the molar concentration of silicon bromide in the composite electrolyte is 0.35M.

[0074] The preparation method of the halide and phosphate composite electrolyte for the rechargeable magnesium battery comprises the following steps: in an argon glove box with water and oxygen contents less than 0.1 ppm, 0.438 g of magnesium bis(trifluoromethylsulfonyl)imide is weighed and added into 1.5 mL of a mixed solvent of ethylene glycol dimethyl ether and tris(trimethylsilyl) phosphate (the volume ratio of ethylene glycol dimethyl ether to tris(trimethylsilyl) phosphate is 95:5), and then the mixture is magnetically stirred at a stirring speed of 600 r / min and a temperature of 30°C for 10 min to ensure that the magnesium bis(trifluoromethylsulfonyl)imide is uniformly dispersed in the mixed solvent of ethylene glycol dimethyl ether and tris(trimethylsilyl) phosphate; then, 0.18 g of silicon bromide is taken by using a pipette and added into the above mixture, and the mixture is magnetically stirred at a stirring speed of 600 r / min and a temperature of 30°C for 10 min, and after sufficient reaction, a colorless, clear and transparent composite electrolyte, namely, 0.5M Mg(TFSI)2 + 0.35M SiBr4 in DME:TMSP (v:v=80:20) composite electrolyte, is obtained.

[0075] Example 4

[0076] The halide and phosphate composite electrolyte for rechargeable magnesium battery provided in this example is composed of magnesium bis(trifluoromethanesulfonyl)imide (as electrolyte salt), ethylene glycol dimethyl ether (as organic ether solvent), tris(trimethylsilyl) phosphate (as phosphate co-solvent) and silicon bromide (as halide additive), the volume ratio of ethylene glycol dimethyl ether to tris(trimethylsilyl) phosphate is 85:15, the molar concentration of magnesium bis(trifluoromethanesulfonyl)imide in the composite electrolyte is 0.5M, and the molar concentration of silicon bromide in the composite electrolyte is 0.5M.

[0077] The preparation method of the halide and phosphate composite electrolyte for rechargeable magnesium battery described above is as follows: 0.438g of magnesium bis(trifluoromethanesulfonyl)imide is weighed in an argon glove box with water and oxygen content less than 0.1ppm, and added to 1.5mL of mixed solvent of ethylene glycol dimethyl ether and tris(trimethylsilyl) phosphate (the volume ratio of ethylene glycol dimethyl ether to tris(trimethylsilyl) phosphate is 85:15), and magnetically stirred at a stirring speed of 600r / min for 10 minutes at a temperature of 30°C to ensure that the magnesium bis(trifluoromethanesulfonyl)imide is uniformly dispersed in the mixed solvent of ethylene glycol dimethyl ether and tris(trimethylsilyl) phosphate; then 0.26g of silicon bromide is taken with a pipette and added to the above mixture, and magnetically stirred at a stirring speed of 600r / min for 10 minutes at a temperature of 30°C, and after the reaction is completed, a colorless clear transparent composite electrolyte, 0.5M Mg(TFSI)2 + 0.5M SiBr4 in DME:TMSP (v:v=85:15) composite electrolyte, is obtained.

[0078] Example 5

[0079] The halide and phosphate composite electrolyte for rechargeable magnesium battery provided in this example is composed of magnesium bis(trifluoromethanesulfonyl)imide (as electrolyte salt), ethylene glycol dimethyl ether (as organic ether solvent), tris(trimethylsilyl) phosphate (as phosphate co-solvent) and silicon bromide (as halide additive), the volume ratio of ethylene glycol dimethyl ether to tris(trimethylsilyl) phosphate is 80:20, the molar concentration of magnesium bis(trifluoromethanesulfonyl)imide in the composite electrolyte is 0.5M, and the molar concentration of silicon bromide in the composite electrolyte is 0.5M.

[0080] The preparation method of the halide and phosphate ester composite electrolyte for the rechargeable magnesium battery comprises the following steps: 0.438 g of magnesium bis(trifluoromethylsulfonyl)imide is weighed in an argon glove box with water and oxygen contents less than 0.1 ppm, and is added to 1.5 mL of a mixed solvent of ethylene glycol dimethyl ether and tris(trimethylsilyl) phosphate (the volume ratio of ethylene glycol dimethyl ether to tris(trimethylsilyl) phosphate is 80:20), and is magnetically stirred at a stirring speed of 600 r / min and a temperature of 30°C for 10 min to ensure that the magnesium bis(trifluoromethylsulfonyl)imide is uniformly dispersed in the mixed solvent of ethylene glycol dimethyl ether and tris(trimethylsilyl) phosphate; then, 0.26 g of silicon bromide is taken by using a pipette and is added to the above mixture, and is magnetically stirred at a stirring speed of 600 r / min and a temperature of 30°C for 10 min, and after sufficient reaction, a colorless, clear and transparent composite electrolyte, namely, 0.5M Mg(TFSI)2 + 0.5M SiBr4 in DME:TMSP (v:v=80:20) composite electrolyte, is obtained.

[0081] Example 6

[0082] The halide and phosphate ester composite electrolyte for the rechargeable magnesium battery provided by the present embodiment is composed of magnesium bis(trifluoromethylsulfonyl)imide (as an electrolyte salt), ethylene glycol dimethyl ether (as an organic ether solvent), tris(trimethylsilyl) phosphate (as a phosphate ester cosolvent) and silicon bromide (as a halide additive), the volume ratio of ethylene glycol dimethyl ether to tris(trimethylsilyl) phosphate is 90:10, the molar concentration of magnesium bis(trifluoromethylsulfonyl)imide in the composite electrolyte is 0.5M, and the molar concentration of silicon bromide in the composite electrolyte is 0.5M.

[0083] The preparation method of the halide and phosphate ester composite electrolyte for the rechargeable magnesium battery comprises the following steps: 0.438 g of magnesium bis(trifluoromethylsulfonyl)imide is weighed in an argon glove box with water and oxygen contents less than 0.1 ppm, and is added to 1.5 mL of a mixed solvent of ethylene glycol dimethyl ether and tris(trimethylsilyl) phosphate (the volume ratio of ethylene glycol dimethyl ether to tris(trimethylsilyl) phosphate is 80:20), and is magnetically stirred at a stirring speed of 600 r / min and a temperature of 30°C for 10 min to ensure that the magnesium bis(trifluoromethylsulfonyl)imide is uniformly dispersed in the mixed solvent of ethylene glycol dimethyl ether and tris(trimethylsilyl) phosphate; then, 0.26 g of silicon bromide is taken by using a pipette and is added to the above mixture, and is magnetically stirred at a stirring speed of 600 r / min and a temperature of 30°C for 10 min, and after sufficient reaction, a colorless, clear and transparent composite electrolyte, namely, 0.5M Mg(TFSI)2 + 0.5M SiBr4 in DME:TMSP (v:v=80:20) composite electrolyte, is obtained.

[0084] Example 7

[0085] The halide and phosphate composite electrolyte for rechargeable magnesium battery provided by the embodiment is composed of the following substances: magnesium bis(trifluoromethylsulfonyl)imide (as an electrolyte salt), ethylene glycol dimethyl ether (as an organic ether solvent), tris(trimethylsilyl) phosphate (as a phosphate co-solvent), and silicon bromide (as a halide additive), the volume ratio of ethylene glycol dimethyl ether to tris(trimethylsilyl) phosphate is 85:15, the molar concentration of magnesium bis(trifluoromethylsulfonyl)imide in the composite electrolyte is 0.5M, and the molar concentration of silicon bromide in the composite electrolyte is 0.2M.

[0086] The preparation method of the halide and phosphate composite electrolyte for rechargeable magnesium battery is as follows: 0.438g of magnesium bis(trifluoromethylsulfonyl)imide is weighed in an argon glove box with water and oxygen contents both less than 0.1ppm, and then added to 1.5mL of a mixed solvent of ethylene glycol dimethyl ether and tris(trimethylsilyl) phosphate (the volume ratio of ethylene glycol dimethyl ether to tris(trimethylsilyl) phosphate is 85:15), and then magnetically stirred at a stirring speed of 600r / min and a temperature of 30℃ for 10 minutes to ensure that the magnesium bis(trifluoromethylsulfonyl)imide is uniformly dispersed in the mixed solvent of ethylene glycol dimethyl ether and tris(trimethylsilyl) phosphate; then 0.10g of silicon bromide is taken by using a pipette and added to the above mixture, and then magnetically stirred at a stirring speed of 600r / min and a temperature of 30℃ for 10 minutes, and then a colorless, clear and transparent composite electrolyte, namely 0.5M Mg(TFSI)2 + 0.2M SiBr4 in DME:TMSP (v:v=85:15) composite electrolyte, is obtained after sufficient reaction.

[0087] Example 8

[0088] The halide and phosphate composite electrolyte for rechargeable magnesium battery provided by the embodiment is composed of the following substances: magnesium bis(trifluoromethylsulfonyl)imide (as an electrolyte salt), ethylene glycol dimethyl ether (as an organic ether solvent), tris(trimethylsilyl) phosphate (as a phosphate co-solvent), and silicon bromide (as a halide additive), the volume ratio of ethylene glycol dimethyl ether to tris(trimethylsilyl) phosphate is 80:20, the molar concentration of magnesium bis(trifluoromethylsulfonyl)imide in the composite electrolyte is 0.5M, and the molar concentration of silicon bromide in the composite electrolyte is 0.2M.

[0089] The preparation method of the halide and phosphate ester composite electrolyte for the rechargeable magnesium battery comprises the following steps: in an argon glove box with water and oxygen contents less than 0.1 ppm, 0.438 g of magnesium bis(trifluoromethylsulfonyl)imide is weighed and added into 1.5 mL of a mixed solvent of ethylene glycol dimethyl ether and tris(trimethylsilyl) phosphate (the volume ratio of ethylene glycol dimethyl ether to tris(trimethylsilyl) phosphate is 80:20), and the mixture is magnetically stirred at a stirring speed of 600 r / min and a temperature of 30°C for 10 min to ensure that the magnesium bis(trifluoromethylsulfonyl)imide is uniformly dispersed in the mixed solvent of ethylene glycol dimethyl ether and tris(trimethylsilyl) phosphate; then, 0.10 g of silicon bromide is taken by using a pipette and added into the above mixture, and the mixture is magnetically stirred at a stirring speed of 600 r / min and a temperature of 30°C for 10 min, and a colorless, clear and transparent composite electrolyte, namely, 0.5 M Mg(TFSI)2 + 0.2 M (M) SiBr4 in DME:TMSP (v:v=80:20) composite electrolyte, is obtained after sufficient reaction.

[0090] Example 9

[0091] The halide and phosphate ester composite electrolyte for the rechargeable magnesium battery provided by the example is composed of magnesium bis(trifluoromethylsulfonyl)imide (as an electrolyte salt), ethylene glycol dimethyl ether (as an organic ether solvent), tris(trimethylsilyl) phosphate (as a phosphate ester cosolvent) and silicon bromide (as a halide additive), the volume ratio of ethylene glycol dimethyl ether to tris(trimethylsilyl) phosphate is 90:10, the molar concentration of magnesium bis(trifluoromethylsulfonyl)imide in the composite electrolyte is 0.5 M, and the molar concentration of silicon bromide in the composite electrolyte is 0.2 M.

[0092] The preparation method of the halide and phosphate ester composite electrolyte for the rechargeable magnesium battery comprises the following steps: in an argon glove box with water and oxygen contents less than 0.1 ppm, 0.438 g of magnesium bis(trifluoromethylsulfonyl)imide is weighed and added into 1.5 mL of a mixed solvent of ethylene glycol dimethyl ether and tris(trimethylsilyl) phosphate (the volume ratio of ethylene glycol dimethyl ether to tris(trimethylsilyl) phosphate is 90:10), and the mixture is magnetically stirred at a stirring speed of 600 r / min and a temperature of 30°C for 10 min to ensure that the magnesium bis(trifluoromethylsulfonyl)imide is uniformly dispersed in the mixed solvent of ethylene glycol dimethyl ether and tris(trimethylsilyl) phosphate; then, 0.10 g of silicon bromide is taken by using a pipette and added into the above mixture, and the mixture is magnetically stirred at a stirring speed of 600 r / min and a temperature of 30°C for 10 min, and a colorless, clear and transparent composite electrolyte, namely, 0.5 M Mg(TFSI)2 + 0.2 M (M) SiBr4 in DME:TMSP (v:v=90:10) composite electrolyte, is obtained after sufficient reaction.

[0093] Example 10

[0094] The halide and phosphate composite electrolyte for rechargeable magnesium battery provided in this example is composed of magnesium bis(trifluoromethanesulfonyl)imide (as electrolyte salt), ethylene glycol dimethyl ether (as organic ether solvent), tris(trimethylsilyl) phosphate (as phosphate co-solvent) and magnesium chloride (as halide additive), the volume ratio of ethylene glycol dimethyl ether to tris(trimethylsilyl) phosphate is 85:15, the molar concentration of magnesium bis(trifluoromethanesulfonyl)imide in the composite electrolyte is 0.5M, and the molar concentration of magnesium chloride in the composite electrolyte is 0.35M.

[0095] The preparation method of the halide and phosphate composite electrolyte for rechargeable magnesium battery described above is as follows: 0.438g of magnesium bis(trifluoromethanesulfonyl)imide is weighed in an argon glove box with water and oxygen content less than 0.1ppm, and added to 1.5mL of mixed solvent of ethylene glycol dimethyl ether and tris(trimethylsilyl) phosphate (the volume ratio of ethylene glycol dimethyl ether to tris(trimethylsilyl) phosphate is 85:15), and magnetically stirred at a stirring speed of 600r / min for 10 minutes at a temperature of 30°C to ensure that the magnesium bis(trifluoromethanesulfonyl)imide is uniformly dispersed in the mixed solvent of ethylene glycol dimethyl ether and tris(trimethylsilyl) phosphate; then 0.05g of magnesium chloride is added to the electrolyte, and magnetically stirred at a stirring speed of 600r / min for 10 minutes at a temperature of 30°C, and after the reaction is completed, a colorless clear transparent composite electrolyte, 0.5M Mg(TFSI)2 + 0.35M MgCl2 in DME:TMSP (v:v=85:15) composite electrolyte, is obtained.

[0096] Example 11

[0097] The halide and phosphate composite electrolyte for rechargeable magnesium battery provided in this example is composed of magnesium bis(trifluoromethanesulfonyl)imide (as electrolyte salt), ethylene glycol dimethyl ether (as organic ether solvent), tris(trimethylsilyl) phosphate (as phosphate co-solvent) and silicon chloride (as halide additive), the volume ratio of ethylene glycol dimethyl ether to tris(trimethylsilyl) phosphate is 85:15, the molar concentration of magnesium bis(trifluoromethanesulfonyl)imide in the composite electrolyte is 0.5M, and the molar concentration of silicon chloride in the composite electrolyte is 0.35M.

[0098] The preparation method of the halide and phosphate ester composite electrolyte for rechargeable magnesium batteries comprises the following steps: in an argon glove box with water and oxygen contents less than 0.1 ppm, 0.438 g of magnesium bis(trifluoromethylsulfonyl)imide is weighed and added to 1.5 mL of a mixed solvent of ethylene glycol dimethyl ether and tri(trimethylsilyl) phosphate (the volume ratio of ethylene glycol dimethyl ether to tri(trimethylsilyl) phosphate is 85:15), and then the mixture is magnetically stirred at a stirring speed of 600 r / min and a temperature of 30°C for 10 min to ensure that the magnesium bis(trifluoromethylsulfonyl)imide is uniformly dispersed in the mixed solvent of ethylene glycol dimethyl ether and tri(trimethylsilyl) phosphate; then, 0.09 g of silicon chloride is added to the electrolyte, and the mixture is magnetically stirred at a stirring speed of 600 r / min and a temperature of 30°C for 10 min, and a colorless, clear and transparent composite electrolyte, i.e., 0.5M Mg(TFSI)2+0.35M SiCl4 in DME:TMSP=85:15 composite electrolyte, is obtained after sufficient reaction.

[0099] Example 12

[0100] The halide and phosphate ester composite electrolyte for rechargeable magnesium batteries provided in the embodiment is composed of magnesium bis(trifluoromethylsulfonyl)imide (as an electrolyte salt), ethylene glycol dimethyl ether (as an organic ether solvent), tripropyl phosphate (as a phosphate ester cosolvent), and silicon bromide (as a halide additive), the volume ratio of ethylene glycol dimethyl ether to tripropyl phosphate is 85:15, the molar concentration of magnesium bis(trifluoromethylsulfonyl)imide in the composite electrolyte is 0.5M, and the molar concentration of silicon bromide in the composite electrolyte is 0.35M.

[0101] The preparation method of the halide and phosphate ester composite electrolyte for rechargeable magnesium batteries comprises the following steps: in an argon glove box with water and oxygen contents less than 0.1 ppm, 0.438 g of magnesium bis(trifluoromethylsulfonyl)imide is weighed and added to 1.5 mL of a mixed solvent of ethylene glycol dimethyl ether and tri(trimethylsilyl) phosphate (the volume ratio of ethylene glycol dimethyl ether to tri(trimethylsilyl) phosphate is 85:15), and then the mixture is magnetically stirred at a stirring speed of 600 r / min and a temperature of 30°C for 10 min to ensure that the magnesium bis(trifluoromethylsulfonyl)imide is uniformly dispersed in the mixed solvent of ethylene glycol dimethyl ether and tri(trimethylsilyl) phosphate; then, 0.09 g of silicon chloride is added to the electrolyte, and the mixture is magnetically stirred at a stirring speed of 600 r / min and a temperature of 30°C for 10 min, and a colorless, clear and transparent composite electrolyte, i.e., 0.5M Mg(TFSI)2+0.35M SiCl4 in DME:TMSP=85:15 composite electrolyte, is obtained after sufficient reaction.

[0102] Example 13

[0103] The halide and phosphate composite electrolyte for rechargeable magnesium battery provided by the embodiment is composed of the following substances: magnesium bis(trifluoromethylsulfonyl)imide (as an electrolyte salt), ethylene glycol dimethyl ether (as an organic ether solvent), tris(trimethylsilyl) phosphate (as a phosphate co-solvent), and antimony bromide (as a halide additive), the volume ratio of ethylene glycol dimethyl ether to tris(trimethylsilyl) phosphate is 85:15, the molar concentration of magnesium bis(trifluoromethylsulfonyl)imide in the composite electrolyte is 0.5M, and the molar concentration of antimony bromide in the composite electrolyte is 0.35M.

[0104] The preparation method of the halide and phosphate composite electrolyte for rechargeable magnesium battery is as follows: 0.438g of magnesium bis(trifluoromethylsulfonyl)imide is weighed in an argon glove box with water and oxygen contents both less than 0.1ppm, and then added to 1.5mL of a mixed solvent of ethylene glycol dimethyl ether and tris(trimethylsilyl) phosphate (the volume ratio of ethylene glycol dimethyl ether to tris(trimethylsilyl) phosphate is 85:15), and then magnetically stirred at a stirring speed of 600r / min and a temperature of 30℃ for 10 minutes to ensure that the magnesium bis(trifluoromethylsulfonyl)imide is uniformly dispersed in the mixed solvent of ethylene glycol dimethyl ether and tris(trimethylsilyl) phosphate; then 0.19g of antimony bromide is added to the electrolyte, and magnetically stirred at a stirring speed of 600r / min and a temperature of 30℃ for 10 minutes, and then a colorless, clear and transparent composite electrolyte, namely 0.5M Mg(TFSI)2 + 0.35MSbBr3 in DME:TMSP (v:v=85:15) composite electrolyte, is obtained after sufficient reaction.

[0105] Example 14

[0106] The halide and phosphate composite electrolyte for rechargeable magnesium battery provided by the embodiment is composed of the following substances: magnesium bis(trifluoromethylsulfonyl)imide (as an electrolyte salt), ethylene glycol dimethyl ether (as an organic ether solvent), tris(trimethylsilyl) phosphate (as a phosphate co-solvent), and antimony bromide (as a halide additive), the volume ratio of ethylene glycol dimethyl ether to tris(trimethylsilyl) phosphate is 85:15, the molar concentration of magnesium bis(trifluoromethylsulfonyl)imide in the composite electrolyte is 0.5M, and the molar concentration of antimony bromide in the composite electrolyte is 0.35M.

[0107] The preparation method of the halide and phosphate composite electrolyte for the rechargeable magnesium battery comprises the following steps: 0.438 g of magnesium bis(trifluoromethylsulfonyl)imide is weighed in an argon glove box with water and oxygen contents less than 0.1 ppm, and then added into 1.5 mL of a mixed solvent of ethylene glycol dimethyl ether and tris(trimethylsilyl) phosphate (the volume ratio of ethylene glycol dimethyl ether to tris(trimethylsilyl) phosphate is 85:15), and then magnetically stirred at a stirring speed of 600 r / min and a temperature of 30°C for 10 min to ensure that the magnesium bis(trifluoromethylsulfonyl)imide is uniformly dispersed in the mixed solvent of ethylene glycol dimethyl ether and tris(trimethylsilyl) phosphate; then, 0.23 g of tin bromide is added into the electrolyte, and then magnetically stirred at a stirring speed of 600 r / min and a temperature of 30°C for 10 min, and then a colorless, clear and transparent composite electrolyte, i.e., 0.5M Mg(TFSI)2 + 0.35M SnBr4 in DME:TMSP (v:v=85:15) composite electrolyte, is obtained after sufficient reaction.

[0108] Example 15

[0109] The halide and phosphate composite electrolyte for the rechargeable magnesium battery provided by the present example is composed of magnesium bis(trifluoromethylsulfonyl)imide (as an electrolyte salt), ethylene glycol dimethyl ether (as an organic ether solvent), tris(trimethylsilyl) phosphate (as a phosphate co-solvent) and boron bromide (as a halide additive), the volume ratio of ethylene glycol dimethyl ether to tris(trimethylsilyl) phosphate is 85:15, the molar concentration of magnesium bis(trifluoromethylsulfonyl)imide in the composite electrolyte is 0.5M, and the molar concentration of boron bromide in the composite electrolyte is 0.35M.

[0110] The preparation method of the halide and phosphate composite electrolyte for the rechargeable magnesium battery comprises the following steps: 0.438 g of magnesium bis(trifluoromethylsulfonyl)imide is weighed in an argon glove box with water and oxygen contents less than 0.1 ppm, and then added into 1.5 mL of a mixed solvent of ethylene glycol dimethyl ether and tris(trimethylsilyl) phosphate (the volume ratio of ethylene glycol dimethyl ether to tris(trimethylsilyl) phosphate is 85:15), and then magnetically stirred at a stirring speed of 600 r / min and a temperature of 30°C for 10 min to ensure that the magnesium bis(trifluoromethylsulfonyl)imide is uniformly dispersed in the mixed solvent of ethylene glycol dimethyl ether and tris(trimethylsilyl) phosphate; then, 0.23 g of tin bromide is added into the electrolyte, and then magnetically stirred at a stirring speed of 600 r / min and a temperature of 30°C for 10 min, and then a colorless, clear and transparent composite electrolyte, i.e., 0.5M Mg(TFSI)2 + 0.35M SnBr4 in DME:TMSP (v:v=85:15) composite electrolyte, is obtained after sufficient reaction.

[0111] Example 16

[0112] The halide and phosphate composite electrolyte for rechargeable magnesium battery provided by the embodiment is composed of the following substances: magnesium bis(trifluoromethylsulfonyl)imide (as electrolyte salt), ethylene glycol dimethyl ether (as organic ether solvent), tris(trimethylsilyl) phosphate (as phosphate co-solvent), and silicon bromide (as halide additive), the volume ratio of ethylene glycol dimethyl ether to tris(trimethylsilyl) phosphate is 85:15, the molar concentration of magnesium bis(trifluoromethylsulfonyl)imide in the composite electrolyte is 0.1M, and the molar concentration of silicon bromide in the composite electrolyte is 0.35M.

[0113] The preparation method of the halide and phosphate composite electrolyte for rechargeable magnesium battery is as follows: 0.088g of magnesium bis(trifluoromethylsulfonyl)imide is weighed in an argon glove box with water and oxygen contents both less than 0.1ppm, and then added to 1.5mL of a mixed solvent of ethylene glycol dimethyl ether and tris(trimethylsilyl) phosphate (the volume ratio of ethylene glycol dimethyl ether to tris(trimethylsilyl) phosphate is 85:15), and then magnetically stirred at a stirring speed of 600r / min and a temperature of 30℃ for 10 minutes to ensure that the magnesium bis(trifluoromethylsulfonyl)imide is uniformly dispersed in the mixed solvent of ethylene glycol dimethyl ether and tris(trimethylsilyl) phosphate; then 0.18g of silicon bromide is added to the electrolyte, and magnetically stirred at a stirring speed of 600r / min and a temperature of 30℃ for 10 minutes, and then a colorless, clear and transparent composite electrolyte, i.e., 0.1M Mg(TFSI)2+0.35M SiBr4 in DME:TMSP (v:v=85:15) composite electrolyte, is obtained after sufficient reaction.

[0114] Example 17

[0115] The halide and phosphate composite electrolyte for rechargeable magnesium battery provided by the embodiment is composed of the following substances: magnesium bis(trifluoromethylsulfonyl)imide (as electrolyte salt), ethylene glycol dimethyl ether (as organic ether solvent), tris(trimethylsilyl) phosphate (as phosphate co-solvent), and silicon bromide (as halide additive), the volume ratio of ethylene glycol dimethyl ether to tris(trimethylsilyl) phosphate is 85:15, the molar concentration of magnesium bis(trifluoromethylsulfonyl)imide in the composite electrolyte is 1.0M, and the molar concentration of silicon bromide in the composite electrolyte is 0.35M.

[0116] The preparation method of the halide and phosphate ester composite electrolyte for the rechargeable magnesium battery comprises the following steps: in an argon glove box with water and oxygen contents less than 0.1 ppm, 0.876 g of magnesium bis(trifluoromethylsulfonyl)imide is weighed and added into 1.5 mL of a mixed solvent of ethylene glycol dimethyl ether and tris(trimethylsilyl) phosphate (the volume ratio of ethylene glycol dimethyl ether to tris(trimethylsilyl) phosphate is 85:15), and then the mixture is magnetically stirred at a stirring speed of 600 r / min and a temperature of 30°C for 10 min to ensure that the magnesium bis(trifluoromethylsulfonyl)imide is uniformly dispersed in the mixed solvent of ethylene glycol dimethyl ether and tris(trimethylsilyl) phosphate; then, 0.18 g of silicon bromide is added into the electrolyte, and the mixture is magnetically stirred at a stirring speed of 600 r / min and a temperature of 30°C for 10 min, and after sufficient reaction, a colorless, clear and transparent composite electrolyte, i.e., 1.0 M Mg(TFSI)2 + 0.35 M SiBr4 in DME:TMSP (v:v=85:15) composite electrolyte, is obtained.

[0117] Example 18

[0118] The halide and phosphate ester composite electrolyte for the rechargeable magnesium battery provided by the example comprises magnesium bis(trifluoromethylsulfonyl)imide (as an electrolyte salt), diethylene glycol dimethyl ether (as an organic ether solvent), tris(trimethylsilyl) phosphate (as a phosphate ester cosolvent), and silicon bromide (as a halide additive), the volume ratio of the diethylene glycol dimethyl ether to the tris(trimethylsilyl) phosphate is 85:15, the molar concentration of the magnesium bis(trifluoromethylsulfonyl)imide in the composite electrolyte is 0.5 M, and the molar concentration of the silicon bromide in the composite electrolyte is 0.35 M.

[0119] The preparation method of the halide and phosphate ester composite electrolyte for the rechargeable magnesium battery comprises the following steps: in an argon glove box with water and oxygen contents less than 0.1 ppm, 0.438 g of magnesium bis(trifluoromethylsulfonyl)imide is weighed and added into 1.5 mL of a mixed solvent of diethylene glycol dimethyl ether and tris(trimethylsilyl) phosphate (the volume ratio of diethylene glycol dimethyl ether to tris(trimethylsilyl) phosphate is 85:15), and then the mixture is magnetically stirred at a stirring speed of 600 r / min and a temperature of 30°C for 10 min to ensure that the magnesium bis(trifluoromethylsulfonyl)imide is uniformly dispersed in the mixed solvent of diethylene glycol dimethyl ether and tris(trimethylsilyl) phosphate; then, 0.18 g of silicon bromide is added into the electrolyte, and the mixture is magnetically stirred at a stirring speed of 600 r / min and a temperature of 30°C for 10 min, and after sufficient reaction, a colorless, clear and transparent composite electrolyte, i.e., 0.5 M Mg(TFSI)2 + 0.35 M SiBr4 in G2:TMSP (v:v=85:15) composite electrolyte, is obtained.

[0120] Example 19

[0121] The halide and phosphate composite electrolyte for rechargeable magnesium battery provided in this example is composed of magnesium bis(trifluoromethanesulfonyl)imide (as electrolyte salt), tetraethylene glycol dimethyl ether (as organic ether solvent), tris(trimethylsilyl) phosphate (as phosphate co-solvent) and silicon bromide (as halide additive), the volume ratio of tetraethylene glycol dimethyl ether to tris(trimethylsilyl) phosphate is 85:15, the molar concentration of magnesium bis(trifluoromethanesulfonyl)imide in the composite electrolyte is 0.5 M, and the molar concentration of silicon bromide in the composite electrolyte is 0.35 M.

[0122] The preparation method of the halide and phosphate composite electrolyte for rechargeable magnesium battery described above is as follows: 0.438 g of magnesium bis(trifluoromethanesulfonyl)imide is weighed in an argon glove box with water and oxygen content less than 0.1 ppm, and added to 1.5 mL of a mixed solvent of tetraethylene glycol dimethyl ether and tris(trimethylsilyl) phosphate (volume ratio of tetraethylene glycol dimethyl ether to tris(trimethylsilyl) phosphate is 85:15), and magnetically stirred at a stirring speed of 600 r / min for 10 minutes at a temperature of 30°C to ensure that the magnesium bis(trifluoromethanesulfonyl)imide is uniformly dispersed in the mixed solvent of tetraethylene glycol dimethyl ether and tris(trimethylsilyl) phosphate; then 0.18 g of silicon bromide is added to the electrolyte, and magnetically stirred at a stirring speed of 600 r / min for 10 minutes at a temperature of 30°C, and after the reaction is completed, a colorless clear transparent composite electrolyte, 0.5 M Mg(TFSI)2+ 0.35 M SiBr4 in G4:TMSP (v:v=85:15) composite electrolyte, is obtained.

[0123] Example 20

[0124] The halide and phosphate composite electrolyte for rechargeable magnesium battery provided in this example is composed of magnesium bis(trifluoromethanesulfonyl)imide (as electrolyte salt), 2-methyltetrahydrofuran (as organic ether solvent), tris(trimethylsilyl) phosphate (as phosphate co-solvent) and silicon bromide (as halide additive), the volume ratio of 2-methyltetrahydrofuran to tris(trimethylsilyl) phosphate is 85:15, the molar concentration of magnesium bis(trifluoromethanesulfonyl)imide in the composite electrolyte is 0.5 M, and the molar concentration of silicon bromide in the composite electrolyte is 0.35 M.

[0125] The preparation method of the halide and phosphate composite electrolyte for the rechargeable magnesium battery comprises the following steps: 0.438 g of magnesium bis(trifluoromethylsulfonyl)imide is weighed in an argon glove box with water and oxygen contents less than 0.1 ppm, and is added to 1.5 mL of a mixed solvent of 2-methyltetrahydrofuran and tris(trimethylsilyl) phosphate (the volume ratio of 2-methyltetrahydrofuran to tris(trimethylsilyl) phosphate is 85:15), and is magnetically stirred at a stirring speed of 600 r / min and a temperature of 30°C for 10 min to ensure that the magnesium bis(trifluoromethylsulfonyl)imide is uniformly dispersed in the mixed solvent of 2-methyltetrahydrofuran and tris(trimethylsilyl) phosphate; then, 0.18 g of silicon bromide is added to the electrolyte, and is magnetically stirred at a stirring speed of 600 r / min and a temperature of 30°C for 10 min, and after sufficient reaction, a colorless, clear and transparent composite electrolyte, i.e., 0.5M Mg(TFSI)2+ 0.35M SiBr4 in MeTHF:TMSP (v:v=85:15) composite electrolyte, is obtained.

[0126] Example 21

[0127] The halide and phosphate composite electrolyte for the rechargeable magnesium battery provided by the example comprises: phenylmagnesium chloride and aluminum chloride (as electrolyte salts), tetrahydrofuran (as an organic ether solvent), tris(trimethylsilyl) phosphate (as a phosphate co-solvent), and silicon bromide (as a halide additive), the volume ratio of tetrahydrofuran to tris(trimethylsilyl) phosphate is 85:15, the molar concentrations of phenylmagnesium chloride and aluminum chloride in the composite electrolyte are 0.5M and 1.0M respectively, and the molar concentration of silicon bromide in the composite electrolyte is 0.35M.

[0128] The preparation method of the halide and phosphate composite electrolyte for the rechargeable magnesium battery comprises the following steps: 0.438 g of magnesium bis(trifluoromethylsulfonyl)imide is weighed in an argon glove box with water and oxygen contents less than 0.1 ppm, and is added to 1.5 mL of a mixed solvent of 2-methyltetrahydrofuran and tris(trimethylsilyl) phosphate (the volume ratio of 2-methyltetrahydrofuran to tris(trimethylsilyl) phosphate is 85:15), and is magnetically stirred at a stirring speed of 600 r / min and a temperature of 30°C for 10 min to ensure that the magnesium bis(trifluoromethylsulfonyl)imide is uniformly dispersed in the mixed solvent of 2-methyltetrahydrofuran and tris(trimethylsilyl) phosphate; then, 0.18 g of silicon bromide is added to the electrolyte, and is magnetically stirred at a stirring speed of 600 r / min and a temperature of 30°C for 10 min, and after sufficient reaction, a colorless, clear and transparent composite electrolyte, i.e., 0.5M Mg(TFSI)2+ 0.35M SiBr4 in MeTHF:TMSP (v:v=85:15) composite electrolyte, is obtained.

[0129] Example 22

[0130] The halide and phosphate composite electrolyte for rechargeable magnesium battery provided in this example is composed of magnesium triflate (as electrolyte salt), ethylene glycol dimethyl ether (as organic ether solvent), tris(trimethylsilyl) phosphate (as phosphate co-solvent) and silicon bromide (as halide additive), the volume ratio of ethylene glycol dimethyl ether to tris(trimethylsilyl) phosphate is 85:15, the molar concentration of magnesium triflate in the composite electrolyte is 0.5M, and the molar concentration of silicon bromide in the composite electrolyte is 0.35M.

[0131] The preparation method of the halide and phosphate composite electrolyte for rechargeable magnesium battery described above is as follows: 0.241g of magnesium triflate is weighed in an argon glove box with water and oxygen content less than 0.1ppm, and added to 1.5mL of a mixed solvent of ethylene glycol dimethyl ether and tris(trimethylsilyl) phosphate (volume ratio of ethylene glycol dimethyl ether to tris(trimethylsilyl) phosphate is 85:15), and magnetically stirred at a stirring speed of 600r / min for 10 minutes at a temperature of 30°C to ensure that the magnesium triflate is uniformly dispersed in the mixed solvent of ethylene glycol dimethyl ether and tris(trimethylsilyl) phosphate; then 0.18g of silicon bromide is added to the electrolyte, and magnetically stirred at a stirring speed of 600r / min for 10 minutes at a temperature of 30°C, and after the reaction is completed, a colorless clear transparent composite electrolyte is obtained, i.e. 0.5M Mg(OTf)2 + 0.35M SiBr4 in DME:TMSP (v:v=85:15) composite electrolyte.

[0132] Example 23

[0133] The halide and phosphate composite electrolyte for rechargeable magnesium battery provided in this example is composed of magnesium bis(trifluoromethanesulfonyl)imide (as electrolyte salt), ethylene glycol dimethyl ether (as organic ether solvent), trimethyl phosphate (as phosphate co-solvent) and silicon bromide (as halide additive), the volume ratio of ethylene glycol dimethyl ether to tris(trimethylsilyl) phosphate is 85:15, the molar concentration of magnesium bis(trifluoromethanesulfonyl)imide in the composite electrolyte is 0.5M, and the molar concentration of silicon bromide in the composite electrolyte is 0.35M.

[0134] The preparation method of the halide and phosphate ester composite electrolyte for the rechargeable magnesium battery comprises the following steps: 0.438 g of magnesium bis(trifluoromethylsulfonyl) imide is weighed in an argon glove box with water and oxygen contents less than 0.1 ppm, and is added to 1.5 mL of a mixed solvent of ethylene glycol dimethyl ether and trimethyl phosphate (the volume ratio of ethylene glycol dimethyl ether to trimethyl phosphate is 85:15), and is magnetically stirred at a stirring speed of 600 r / min and a temperature of 30°C for 10 min to ensure that the magnesium bis(trifluoromethylsulfonyl) imide is uniformly dispersed in the mixed solvent of ethylene glycol dimethyl ether and trimethyl phosphate; then, 0.18 g of silicon bromide is added to the electrolyte, and is also magnetically stirred at a stirring speed of 600 r / min and a temperature of 30°C for 10 min, and after sufficient reaction, a colorless, clear and transparent composite electrolyte, i.e., 0.5M Mg(TFSI)2+0.35M SiBr4 in DME:TMP (v:v=85:15) composite electrolyte, is obtained.

[0135] Example 24

[0136] The halide and phosphate ester composite electrolyte for the rechargeable magnesium battery provided in the embodiment comprises magnesium bis(trifluoromethylsulfonyl) imide (as an electrolyte salt), ethylene glycol dimethyl ether (as an organic ether solvent), triethyl phosphate (as a phosphate ester cosolvent), and silicon bromide (as a halide additive), the volume ratio of ethylene glycol dimethyl ether to triethyl phosphate is 85:15, the molar concentration of magnesium bis(trifluoromethylsulfonyl) imide in the composite electrolyte is 0.5M, and the molar concentration of silicon bromide in the composite electrolyte is 0.35M.

[0137] The preparation method of the halide and phosphate ester composite electrolyte for the rechargeable magnesium battery comprises the following steps: 0.438 g of magnesium bis(trifluoromethylsulfonyl) imide is weighed in an argon glove box with water and oxygen contents less than 0.1 ppm, and is added to 1.5 mL of a mixed solvent of ethylene glycol dimethyl ether and trimethyl phosphate (the volume ratio of ethylene glycol dimethyl ether to trimethyl phosphate is 85:15), and is magnetically stirred at a stirring speed of 600 r / min and a temperature of 30°C for 10 min to ensure that the magnesium bis(trifluoromethylsulfonyl) imide is uniformly dispersed in the mixed solvent of ethylene glycol dimethyl ether and trimethyl phosphate; then, 0.18 g of silicon bromide is added to the electrolyte, and is also magnetically stirred at a stirring speed of 600 r / min and a temperature of 30°C for 10 min, and after sufficient reaction, a colorless, clear and transparent composite electrolyte, i.e., 0.5M Mg(TFSI)2+0.35M SiBr4 in DME:TMP (v:v=85:15) composite electrolyte, is obtained.

[0138] Example 25

[0139] The halide and phosphate composite electrolyte for rechargeable magnesium battery provided by the embodiment is composed of the following substances: magnesium tetra (hexafluoroisopropoxyborate) (as an electrolyte salt), ethylene glycol dimethyl ether (as an organic ether solvent), tris (trimethylsilyl) phosphate (as a phosphate co-solvent), and silicon bromide (as a halide additive). The volume ratio of ethylene glycol dimethyl ether to tris (trimethylsilyl) phosphate is 85:15. The molar concentration of magnesium tetra (hexafluoroisopropoxyborate) in the composite electrolyte is 0.3M, and the molar concentration of silicon bromide in the composite electrolyte is 0.35M.

[0140] The preparation method of the halide and phosphate composite electrolyte for rechargeable magnesium battery is as follows: in an argon glove box with water and oxygen contents both less than 0.1ppm, 0.576g of magnesium tetra (hexafluoroisopropoxyborate) is weighed and added to 1.5mL of a mixed solvent of ethylene glycol dimethyl ether and tris (trimethylsilyl) phosphate (the volume ratio of ethylene glycol dimethyl ether to tris (trimethylsilyl) phosphate is 85:15). The temperature is kept at 30℃ with magnetic stirring at a stirring speed of 600r / min for 10 minutes to ensure that the magnesium tetra (hexafluoroisopropoxyborate) is uniformly dispersed in the mixed solvent of ethylene glycol dimethyl ether and tris (trimethylsilyl) phosphate. Then, 0.18g of silicon bromide is added to the electrolyte, and the temperature is kept at 30℃ with magnetic stirring at a stirring speed of 600r / min for 10 minutes. After sufficient reaction, a colorless, clear and transparent composite electrolyte, 0.3M Mg[B(HFIP)4]2 +0.35M SiBr4 in DME:TMSP (v:v=85:15) composite electrolyte, is obtained.

[0141] Comparative Example 1

[0142] The preparation method of the composite electrolyte provided by the comparative example is as follows: in an argon glove box with water and oxygen contents both less than 0.1ppm, 0.438g of magnesium bis (trifluoromethylsulfonyl) imide is weighed and added to 1.5mL of ethylene glycol dimethyl ether (as an ether solvent). The temperature is kept at 30℃ with magnetic stirring at a stirring speed of 600r / min for 10 minutes to ensure that the magnesium bis (trifluoromethylsulfonyl) imide is uniformly dispersed in the ethylene glycol dimethyl ether to form a colorless, transparent and clear liquid, and a blank composite electrolyte of 0.5M Mg(TFSI)2 in DME is obtained.

[0143] Comparative Example 2

[0144] The composite electrolyte provided by the present comparative example is prepared as follows: 0.438 g of magnesium bis(trifluoromethylsulfonyl)imide is weighed in an argon glove box with water and oxygen contents of less than 0.1 ppm, and added to 1.5 mL of ethylene glycol dimethyl ether (as an ether solvent). The mixture is stirred at a speed of 600 r / min and a temperature of 30°C for 10 min to ensure that the magnesium bis(trifluoromethylsulfonyl)imide is uniformly dispersed in the ethylene glycol dimethyl ether to form a colorless transparent clear liquid, thereby obtaining a 0.5M Mg(TFSI)2 in DME blank electrolyte. Then, 0.05 g of magnesium chloride is added to the blank electrolyte using a pipette, and the mixture is stirred at a speed of 600 r / min and a temperature of 30°C for 10 min. After the reaction is completed, a yellow clear transparent composite electrolyte, i.e., a 0.5M Mg(TFSI)2 + 0.35M MgCl2 in DME composite electrolyte, is obtained.

[0145] Comparative Example 3

[0146] The composite electrolyte provided by the present comparative example is prepared as follows: 0.438 g of magnesium bis(trifluoromethylsulfonyl)imide is weighed in an argon glove box with water and oxygen contents of less than 0.1 ppm, and added to 1.5 mL of ethylene glycol dimethyl ether (as an ether solvent). The mixture is stirred at a speed of 600 r / min and a temperature of 30°C for 10 min to ensure that the magnesium bis(trifluoromethylsulfonyl)imide is uniformly dispersed in the ethylene glycol dimethyl ether to form a colorless transparent clear liquid, thereby obtaining a 0.5M Mg(TFSI)2 in DME blank electrolyte. Then, 0.09 g of silicon chloride is added to the blank electrolyte using a pipette, and the mixture is stirred at a speed of 600 r / min and a temperature of 30°C for 10 min. After the reaction is completed, a yellow clear transparent composite electrolyte, i.e., a 0.5M Mg(TFSI)2 + 0.35M SiCl4 in DME composite electrolyte, is obtained.

[0147] Comparative Example 4

[0148] The composite electrolyte provided by the present comparative example is prepared as follows: 0.438 g of magnesium bis(trifluoromethylsulfonyl)imide is weighed in an argon glove box with water and oxygen contents of less than 0.1 ppm, and added to 1.5 mL of ethylene glycol dimethyl ether (as an ether solvent). The mixture is stirred at a speed of 600 r / min and a temperature of 30°C for 10 min to ensure that the magnesium bis(trifluoromethylsulfonyl)imide is uniformly dispersed in the ethylene glycol dimethyl ether to form a colorless transparent clear liquid, obtaining a 0.5M Mg(TFSI)2 in DME blank electrolyte. Then, 0.18 g of silicon bromide is taken using a pipette and added to the above blank electrolyte. The mixture is stirred at a speed of 600 r / min and a temperature of 30°C for 10 min to ensure that the silicon bromide is fully reacted, obtaining a yellow clear transparent composite electrolyte, i.e., a 0.5M Mg(TFSI)2 + 0.35M SiBr4 in DME composite electrolyte.

[0149] Comparative Example 5

[0150] The composite electrolyte provided by the present comparative example is prepared as follows: 0.438 g of magnesium bis(trifluoromethylsulfonyl)imide is weighed in an argon glove box with water and oxygen contents of less than 0.1 ppm, and added to 1.5 mL of ethylene glycol dimethyl ether (as an ether solvent). The mixture is stirred at a speed of 600 r / min and a temperature of 30°C for 10 min to ensure that the magnesium bis(trifluoromethylsulfonyl)imide is uniformly dispersed in the ethylene glycol dimethyl ether to form a colorless transparent clear liquid, obtaining a 0.5M Mg(TFSI)2 in DME blank electrolyte. Then, 0.19 g of antimony bromide is taken using a pipette and added to the above blank electrolyte. The mixture is stirred at a speed of 600 r / min and a temperature of 30°C for 10 min to ensure that the antimony bromide is fully reacted, obtaining a yellow clear transparent composite electrolyte, i.e., a 0.5M Mg(TFSI)2 + 0.35M SbBr3 in DME composite electrolyte.

[0151] Comparative Example 6

[0152] The composite electrolyte provided by the present comparative example is prepared by the following method: 0.438 g of magnesium bis(trifluoromethylsulfonyl)imide is weighed in an argon glove box with water and oxygen contents of less than 0.1 ppm, and added to 1.5 mL of ethylene glycol dimethyl ether (as an ether solvent). The mixture is stirred at a speed of 600 r / min and a temperature of 30°C for 10 min to ensure that the magnesium bis(trifluoromethylsulfonyl)imide is uniformly dispersed in the ethylene glycol dimethyl ether to form a colorless transparent clear liquid, thereby obtaining a 0.5M Mg(TFSI)2 in DME blank electrolyte. Then, 0.23 g of tin bromide is taken using a pipette and added to the above blank electrolyte. The mixture is stirred at a speed of 600 r / min and a temperature of 30°C for 10 min to ensure that the tin bromide is fully reacted, thereby obtaining a yellow clear transparent composite electrolyte, i.e., a 0.5M Mg(TFSI)2 + 0.35M SnBr4 in DME composite electrolyte.

[0153] Comparative Example 7

[0154] The composite electrolyte provided by the present comparative example is prepared by the following method: 0.438 g of magnesium bis(trifluoromethylsulfonyl)imide is weighed in an argon glove box with water and oxygen contents of less than 0.1 ppm, and added to 1.5 mL of ethylene glycol dimethyl ether (as an ether solvent). The mixture is stirred at a speed of 600 r / min and a temperature of 30°C for 10 min to ensure that the magnesium bis(trifluoromethylsulfonyl)imide is uniformly dispersed in the ethylene glycol dimethyl ether to form a colorless transparent clear liquid, thereby obtaining a 0.5M Mg(TFSI)2 in DME blank electrolyte. Then, 0.23 g of tin bromide is taken using a pipette and added to the above blank electrolyte. The mixture is stirred at a speed of 600 r / min and a temperature of 30°C for 10 min to ensure that the tin bromide is fully reacted, thereby obtaining a yellow clear transparent composite electrolyte, i.e., a 0.5M Mg(TFSI)2 + 0.35M SnBr4 in DME composite electrolyte.

[0155] Comparative Example 8

[0156] The composite electrolyte provided by the present comparative example is prepared by the following method: 0.438 g of magnesium bis(trifluoromethylsulfonyl)imide is weighed in an argon glove box with water and oxygen contents of less than 0.1 ppm, and added to 1.5 mL of ethylene glycol dimethyl ether (as an ether solvent). The mixture is stirred at a speed of 600 r / min and a temperature of 30°C for 10 min to ensure that the magnesium bis(trifluoromethylsulfonyl)imide is uniformly dispersed in the ethylene glycol dimethyl ether to form a colorless transparent clear liquid, thereby obtaining a 0.5M Mg(TFSI)2 in DME blank electrolyte. Then, 0.23 g of tin bromide is taken using a pipette and added to the above blank electrolyte. The mixture is stirred at a speed of 600 r / min and a temperature of 30°C for 10 min to ensure that the tin bromide is fully reacted, thereby obtaining a yellow clear transparent composite electrolyte, i.e., a 0.5M Mg(TFSI)2 + 0.35M SnBr4 in DME composite electrolyte.

[0157] Comparative Example 9

[0158] The composite electrolyte provided by the present comparative example was prepared by: weighing 0.438 g of magnesium bis(trifluoromethylsulfonyl)imide in an argon glovebox with both water and oxygen content lower than 0.1 ppm, adding into 1.5 mL of mixed solvent of ethylene glycol dimethyl ether and tripropyl phosphate (v:v = 85:15), keeping the temperature at 30 °C with magnetic stirring at 600 r / min for 10 min, ensuring that the magnesium bis(trifluoromethylsulfonyl)imide was uniformly dispersed in the mixed solvent of ethylene glycol dimethyl ether and tripropyl phosphate to form a colorless transparent clear liquid, obtaining a 0.5M Mg(TFSI)2 in DME:TPP (v:v = 85:15) blank composite electrolyte.

[0159] The composite electrolyte obtained by the present application was added with 4 Å molecular sieves for overnight drying before use.

[0160] The electrolytes prepared in Examples 1-15 and Comparative Examples 1-9 were characterized and tested for performance, and the results are shown in Figures 1-13 .

[0161] Figure 1 The photo images of the electrolytes prepared in Examples 10-15 and Comparative Examples 2-7 and the XRD images of the magnesium sheets after soaking for 30 min with magnesium sheets are shown in (a) for Example 10 (left) and Comparative Example 2 (right), (b) for Example 11 (left) and Comparative Example 3 (right), (c) for Example 12 (left) and Comparative Example 4 (right), (d) for Example 13 (left) and Comparative Example 5 (right), (e) for Example 14 (left) and Comparative Example 6 (right), and (f) for Example 15 (left) and Comparative Example 7 (right). The test results show that the corrosion of the blank 0.5M Mg(TFSI)2 in DME electrolyte with the addition of halide additive is greater, and the addition of phosphate co-solvent and halide additive significantly reduces the corrosion. The XRD spectrum results support the above conclusion. The magnesium sheet in the composite electrolyte with only the addition of halide additive shows suppressed magnesium signal and the appearance of impurity peaks, while the magnesium sheet in the composite electrolyte with the addition of phosphate co-solvent and halide additive retains clear magnesium reflection signal and no obvious impurities appear.

[0162] Figure 2 The Tafel curve of the composite electrolyte prepared in Example 1, Comparative Example 1 and Comparative Example 4 is shown. The test results show that the exchange current density of the 0.5M Mg(TFSI)2 + 0.35M SiBr4 in DME:TMSP (v:v = 85:15) electrolyte reaches 1.04 x 10 -6 μA·cm-2 Compared to 0.5M Mg(TFSI)2 + 0.35M SiBr4 in DME electrolyte, which has a concentration of 2.12 × 10⁻⁶. -8 μA·cm -2 Two orders of magnitude higher than the original 0.5M Mg(TFSI)2 in DME electrolyte (1.30 × 10⁻⁶). -9 μA·cm -2 This represents an improvement of nearly three orders of magnitude. This significant improvement is primarily due to reduced Mg. 2+ The synergistic effect of desolvation barrier and the formation of highly conductive SEI film together accelerate the interfacial charge transfer kinetics.

[0163] The linear voltammetric test curves of the composite electrolytes prepared in Test Example 1 and Comparative Example 4 were obtained. The specific process was as follows: the working electrode was a copper, stainless steel, molybdenum and aluminum electrode, the auxiliary electrode was a platinum wire electrode, and the reference electrode was a magnesium metal reference electrode. The composite electrolytes of Test Example 1 and Comparative Example 4 were taken respectively, and a three-electrode electrolytic cell was assembled in an argon glove box (water oxygen content <0.1ppm) to ensure that the electrodes were completely immersed in the electrolyte. Figure 3 Linear voltammetric curves of the composite electrolytes prepared in Example 1 (right) and Comparative Example 4 (left) are shown. The test results show that in the 0.5M Mg(TFSI)2 + 0.35M(M)SiBr4in DME electrolyte, both the copper electrode (Cu) and the stainless steel electrode (SS) undergo oxidative decomposition at low potentials (both below 2.5 V), while the oxidative decomposition potential of the molybdenum electrode (Mo) increases to ~3.76 V (relative to Mg). 2+ / Mg). In contrast, the 0.5M Mg(TFSI)2 +0.35M(M)SiBr4 in DME:TMSP (v:v=85:15) composite electrolyte significantly improved the oxidation stability of all electrodes, with the oxidation decomposition potential of the molybdenum electrode exceeding 3.94 V, fully demonstrating its excellent antioxidant decomposition performance.

[0164] The charge-discharge curves and cycle stability of the magnesium anode in the composite electrolytes prepared in Example 1, Comparative Example 1, and Comparative Example 4 were tested. The specific procedure was as follows: Magnesium foil (0.3 mm thick) was cut into 15 mm diameter discs, sanded until smooth, wiped with DME, and then dried. A symmetrical battery system (magnesium anode | electrolyte | magnesium anode) was used for testing, with a glass fiber membrane (19 mm diameter) as the separator. In an argon glove box (water oxygen < 0.1 ppm), the magnesium foil, separator, electrolyte (50-100 μL added, ensuring the separator is wetted), and positive electrode were sequentially placed into a CR2025 coin cell casing and sealed. The test was conducted using a Newway battery testing system in constant current charge-discharge mode.Figure 4 Charge-discharge curves and cycle stability of magnesium negative electrode in composite electrolytes prepared in Example 1, Comparative Example 1 and Comparative Example 4 (constant current charge-discharge current density is 0.1 mA-cm -2 , constant area capacity is 0.1 mAh-cm -2 ). The test results show the charge-discharge performance of the electrolyte with single addition of halide additive and simultaneous addition of halide additive and phosphate-based cosolvent in 0.5M Mg(TFSI)2 in DME electrolyte in Mg||Mg symmetric battery, set the constant current charge-discharge current density is 0.1 mA-cm -2 , constant area capacity is 0.1 mAh-cm -2 . The addition of silicon bromide significantly reduces the overpotential of magnesium metal dissolution / deposition, greatly promotes the interface charge mass transfer kinetics, and the high conductivity SEI generated by the simultaneous addition of phosphate-based cosolvent has sufficient stability, significantly improves the reversibility and durability of the magnesium electrode. It shows that the Mg 2+ ion in MST can easily overcome the interface energy barrier and realize nucleation under minimal external polarization. And with continuous deposition, the overpotential further decreases.

[0165] The charge-discharge curves and cycle stability of the magnesium negative electrode in the composite electrolytes prepared in Examples 2-9 were tested. The specific process is as follows: the magnesium negative electrode adopts magnesium foil (thickness 0.3mm), which is cut into a circular piece with a diameter of 15mm, and is polished to a smooth surface with sandpaper. After wiping the surface with DME, dry it. Select the symmetric battery system (magnesium negative electrode | electrolyte | magnesium negative electrode) for testing, and the separator is a glass fiber separator (diameter 19mm). In an argon glove box (water and oxygen <0.1ppm), the magnesium foil, the separator, the electrolyte (dropwise amount 50-100μL, ensure that the separator is soaked), and the positive electrode are sequentially loaded into the CR2025 button cell shell, and then sealed. Use the new battery test system, select the constant current charge-discharge mode for testing. Figure 5 Charge-discharge curves and cycle stability of magnesium negative electrode in composite electrolytes prepared in Examples 2-9 (constant current charge-discharge current density is 0.1 mA-cm -2 , constant area capacity is 0.1 mAh-cm -2 ). The test results show that too little phosphate cosolvent leads to too little protective SEI layer, which is easy to short circuit; too much phosphate cosolvent is not easy to conduct, which may increase, resulting in a decrease in cycle performance; too little bromide additive, less SEI layer of high conductivity magnesium bromide, poor cycle performance; too much bromide additive, which may lead to too thick SEI layer and reduced cycle stability.

[0166] Figure 6Charge-discharge curves and cycle stability of Mg||Mg symmetric cells with Mg anodes in composite electrolytes prepared in Example 1, Comparative Example 1 and Comparative Example 4 (constant area capacity of 0.5 mAh cm -2 , constant current charge-discharge current density of 0.5 mA cm -2 ). The test results show the charge-discharge performance of the electrolyte with single halide additive and the electrolyte with halide additive and phosphate co-solvent in 0.5 M Mg(TFSI)2 in DME electrolyte in Mg||Mg symmetric cells, with constant current charge-discharge current density of 0.5 mA cm -2 , constant area capacity of 0.5 mAh cm -2 . Even if the current density is increased by five times, the symmetric cell has a low overpotential (less than 0.4 V) and can maintain a cycle performance of more than 300 h, indicating that the electrolyte has more excellent magnesium metal anode electrochemical performance.

[0167] Figure 7 Charge-discharge curves and cycle stability of Mg||Mg symmetric cells with Mg anodes in composite electrolytes prepared in Example 25 (constant current charge-discharge current density of 0.1 mA cm -2 , constant area capacity of 0.1 mAh cm -2 ). The test results show that the composite electrolyte with halide additive and phosphate co-solvent in 0.3 M Mg[B(HFIP)4]2 + 0.35 M SiBr4 in DME:TMSP (v:v=85:15) still has relatively excellent magnesium metal anode electrochemical performance.

[0168] Figure 8 Rate polarization performance curve of Mg||Mg symmetric cells with composite electrolytes prepared in Example 1, Comparative Example 1 and Comparative Example 4 at different current densities (constant area capacity of 0.1 mAh cm -2 ). It can be seen that by adding tris(trimethylsilyl) phosphate, the overpotential at high current density is significantly improved, and even if the current density is increased from 0.1 mA cm -2 to 3 mA cm -2 , stable magnesium metal dissolution / deposition behavior can still be maintained, indicating that the composite electrolyte of the application has excellent rate performance.

[0169] Figure 9 Rate polarization performance curve of Mg||Mg symmetric cells with composite electrolytes prepared in Example 16-24 at different current densities (constant area capacity of 0.1 mAh cm -2 ). The test results show that the simultaneous addition of halide additive and phosphate co-solvent has relatively good effect in different systems.

[0170] Figure 10 Nyquist plots (EIS) of the composite electrolytes prepared for Example 1, Comparative Example 1 and Comparative Example 4 after different cycles of magnesium metal dissolution / deposition electrochemical test in Mg||Mg symmetric cell, wherein (a) is Comparative Example 1, (b) is Comparative Example 4, (c) is Example 1. The test results show that the addition of tris(trimethylsilyl) phosphate can significantly reduce the interfacial transfer resistance, indicating that its excellent charge transfer kinetics needs a small current electrochemical regulation process, and also indicating that the composite electrolyte of the application has excellent magnesium metal negative electrode electrochemical performance.

[0171] Figure 11 Charge-discharge curves and cycle stability of the composite electrolytes prepared for Example 1, Comparative Example 1 and Comparative Example 4 in Mg||Mo asymmetric cell composed of Mo electrode and magnesium electrode at different cutoff voltages. The test results show that in PM electrolyte, the plating / peeling process of magnesium electrode shows a high overpotential of up to ~2.68 V, and when the cutoff voltage is 1.0 V and 1.2 V respectively, the coulombic efficiency is only 1.52% and 4.60%. These low efficiency data expose serious interface side reactions and insufficient utilization of active magnesium, resulting in limited electrochemical oxidation window. In contrast, the MS electrolyte significantly reduces the overpotential to ~0.83 V, and can achieve a coulombic efficiency of more than 85% in the range of 1.0-1.6 V. But as the cutoff voltage exceeds 2.0 V, the coulombic efficiency gradually decreases, indicating that the interface layer derived from the addition of halide additives alone lacks sufficient oxidation stability. Notably, the MST electrolyte enables the Mg||Mo asymmetric cell to maintain ultra-low hysteresis and near-ideal coulombic efficiency (~99%) even at a cutoff voltage as high as 3.6 V, highlighting the stable low-impedance interface layer formed by it can effectively suppress negative reactions at high potential.

[0172] Figure 12 Cycle performance, charge-discharge curves and coulombic efficiency of the composite electrolyte prepared for Example 1 in Mg||Mo asymmetric cell composed of Mo electrode and magnesium electrode at a cutoff voltage of 3.4 V, wherein (a) is cycle performance, (b) is coulombic efficiency, (c) is charge-discharge curve. The test results show that under the condition of 0.1 mA·cm -2 current density, reversible dissolution and deposition cycles can be carried out on the Mo working electrode, and the deposition overpotential and dissolution overpotential are low, and the average coulombic efficiency can be operated at a coulombic efficiency of more than 90% under the condition of a cutoff voltage of 3.4 V. These test results show that the composite electrolyte of the application has excellent magnesium metal dissolution / deposition performance.

[0173] Figure 13SEM images (scale bar: 50 pm) of the composite electrolyte prepared for Example 1, Comparative Example 1 and Comparative Example 4 after 200 h of magnesium metal dissolution / deposition electrochemical test, wherein (a) is Comparative Example 1, (b) is Comparative Example 4, and (c) is Example 1. The test results show that after the charge and discharge, the magnesium electrode surface presents a uniform and dense magnesium deposit, indicating that the composite electrolyte of the present application has excellent magnesium metal negative electrode electrochemical performance.

[0174] Figure 14 Cycle performance curves of the composite electrolyte prepared for Example 1, Comparative Example 1 and Comparative Example 4 at different rates in Mg||Mo6S8 full cells. The test results show that in the original PM electrolyte, the releasable capacity at all rates is almost negligible, which reflects the serious interface instability and slow Mg 2+ transport kinetics, hindering effective Mg 2+ insertion / extraction. When using the MS electrolyte, the battery exhibits significant capacity at 0.1 C, but there is a sharp decline as the current density increases, and the capacity does not fully recover when returning to 0.1 C, indicating significant polarization and poor reversibility. In contrast, the MST electrolyte maintains significantly higher capacity over a wide range of rates, almost achieving full capacity recovery at 0.1 C, highlighting its excellent rate performance and electrochemical reversibility.

[0175] Figure 15 Cycle performance curves of the composite electrolyte prepared for Example 1 and Comparative Example 4 at 0.5 C rate in Mg||Mo6S8 full cells. The initial capacity of the Mg||Mo6S8 full cell is 80.03 mA·h·g -1 , after 200 cycles at a charge rate of 0.5 C in the electrolyte of Example 1, the coulombic efficiency can still maintain 91.52%; while the initial capacity of the MS battery is 57.28 mA·h·g -1 , after 200 cycles at a charge rate of 0.5 C, the coulombic efficiency can only be maintained at 68.10%. And the battery assembled using the MST electrolyte always maintains more than 99% of the coulombic efficiency throughout the cycle process, which indicates that the stable SEI effectively suppresses the negative reaction.

[0176] Figure 16 Cycle performance curves of the composite electrolyte prepared for Example 1 at 0.5 C rate in Mg||PANI-V2O5 full cells. The initial capacity of the Mg||PANI-V2O5 full cell using the electrolyte of Example 1 is 128.0 mA·h·g -1 , after 50 cycles, it provides a specific capacity of 93.6 mA·h·g -1 , the capacity retention rate is 73.13%, and the coulombic efficiency is close to 100%.

[0177] The above merely provides the preferred embodiment of the application, and the protection scope of the application is not limited thereto. Any modification or replacement readily conceived by those skilled in the art within the technical scope of the application should be covered within the protection scope of the application.

Claims

1. A halogenated compound and phosphate ester composite electrolyte for rechargeable magnesium batteries, characterized in that, Including electrolyte salts, organic ether solvents, phosphate ester cosolvents, and halogenated additives; The electrolyte salt is an organic magnesium salt.

2. The halide-phosphate composite electrolyte for rechargeable magnesium batteries according to claim 1, characterized in that, The organic magnesium salt is selected from one of bis(trifluoromethanesulfonyl)imide magnesium, magnesium trifluoromethanesulfonate, chlorine-containing complex magnesium salt, and tetra(hexafluoroisopropoxyboronic acid) magnesium.

3. The halide-phosphate composite electrolyte for rechargeable magnesium batteries according to claim 1, characterized in that, The organic ether solvent is selected from at least one of tetrahydrofuran, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, and 2-methyltetrahydrofuran.

4. The halide-phosphate composite electrolyte for rechargeable magnesium batteries according to claim 1, characterized in that, The phosphate ester cosolvent is selected from one of trimethyl phosphate, triethyl phosphate, tripropyl phosphate, and tris(trimethylsilane) phosphate.

5. The halide-phosphate composite electrolyte for rechargeable magnesium batteries according to claim 1, characterized in that, The halogenated additive is selected from one of magnesium chloride, silicon chloride, silicon bromide, antimony bromide, tin bromide, and boron bromide.

6. The halide-phosphate composite electrolyte for rechargeable magnesium batteries according to claim 1, characterized in that, The molar concentration of the electrolyte salt in the halide-phosphate composite electrolyte for rechargeable magnesium batteries is 0.1-1.0 M.

7. The halide-phosphate composite electrolyte for rechargeable magnesium batteries according to claim 1, characterized in that, The molar concentration of the halogenated additive in the halogenated and phosphate ester composite electrolyte for rechargeable magnesium batteries is 0.2-0.5M.

8. A method for preparing a halide-phosphate ester composite electrolyte for a rechargeable magnesium battery according to any one of claims 1-7, characterized in that, The process includes the following steps: adding an electrolyte salt to a mixed solvent consisting of an organic ether solvent and a phosphate ester co-solvent, stirring until homogeneous, adding a halogenated additive, and stirring again to obtain the halogenated and phosphate ester composite electrolyte for rechargeable magnesium batteries.

9. A rechargeable magnesium battery, characterized in that, The electrolyte is the halogenated compound electrolyte and phosphate ester composite electrolyte for rechargeable magnesium batteries as described in any one of claims 1-7.

10. The application of the halogenated compound electrolyte with phosphate ester as described in claim 8 in the preparation of a rechargeable magnesium battery.

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