Halogen-free single-solvent rechargeable magnesium battery electrolyte and preparation method and application thereof

Abstract

The invention provides an electrolyte of a magnesium battery. The electrolyte comprises magnesium salt and an amine organic solvent, the general formula of the amine organic solvent is shown in the formula (1), and R1, R2 and R3 are independently selected from alkyl groups. The halogen-free single-solvent rechargeable magnesium battery electrolyte provided by the invention does not contain halogen elements, so that corrosion to a current collector is avoided; the raw materials are low in price and simple in formula, and do not contain complex additive components; meanwhile, the overpotential is low, the magnesium deposition-dissolution efficiency is high, and the oxidation stability is high. The invention further provides a preparation method of the magnesium battery electrolyte, the preparation process is simple, convenient and efficient, and industrial large-scale production is facilitated.

Description

Technical Field

[0001] The present invention belongs to the technical field of battery materials, and relates to an electrolyte for a magnesium battery and a preparation method thereof, and a magnesium secondary battery, and in particular to a halogen-free single-solvent rechargeable magnesium battery electrolyte and a preparation method and application thereof. Background Art

[0002] The research and development of rechargeable secondary batteries is the key to solving the problem of renewable energy storage. In this context, rechargeable magnesium batteries (magnesium secondary batteries) have attracted widespread attention due to their unique advantages: magnesium metal has abundant resources (the reserves in the earth's crust are as high as 2.7%), low standard electrode potential (2.37V SHE), ultra-high theoretical specific capacity (3833mAh cm -3 ) and other comprehensive properties. Therefore, magnesium secondary batteries using magnesium metal as the negative electrode have become a new energy storage system with great development potential. However, magnesium metal is easily passivated in most magnesium salt electrolytes, resulting in interfacial stability issues, which seriously restricts the development of rechargeable magnesium batteries.

[0003] At present, researchers have developed a variety of electrolyte systems. The current mainstream "first generation" magnesium-based electrolyte (DCC), "second generation" magnesium-based electrolyte (APC) and inorganic magnesium chloride-based electrolyte (MACC) all require the addition of halogens to improve electrolyte performance. However, the addition of halogens will inevitably lead to the problem of current collector corrosion, which further leads to low oxidative stability. In recent years, newly developed non-corrosive electrolytes, such as monocarborane, fluorinated alcohol magnesium borate and fluorinated alkoxyaluminate alkoxyborate, have high oxidative stability, but the synthesis process of the above systems is complex, the reaction conditions are harsh, and the price is expensive. Compared with the above-mentioned custom-synthesized magnesium borate or magnesium aluminate salts, commercial simple magnesium salts such as bis(trifluoromethanesulfonyl)imide magnesium and magnesium trifluoromethanesulfonate are more popular due to their mature synthesis routes. However, the anions of these magnesium salts are small in size and have poor dissociation ability in conventional ether solvents, resulting in the formation of a surface film dominated by inorganic substances. This cannot serve as an effective solid electrolyte interface (SEI) to promote magnesium ion migration, and often requires the addition of additives to induce the formation of an organic surface film. However, such strategies usually increase additional costs and weaken the stability of the electrode interface.

[0004] Therefore, how to find a more suitable rechargeable magnesium battery electrolyte to solve the above-mentioned technical problems existing in the existing magnesium secondary battery electrolyte is extremely urgent and important, and is also one of the focuses of widespread attention of many front-line scientific researchers and R&D companies in the field. Summary of the Invention

[0005] In view of this, the technical problem to be solved by the present invention is to provide an electrolyte for a magnesium battery and a preparation method thereof, a magnesium secondary battery, and particularly a halogen-free single-solvent rechargeable magnesium battery electrolyte. The present invention forms an interface film dominated by organic matter on the surface of the magnesium negative electrode through the direct coordination of amine solvents and magnesium ions, and the film can serve as a solid electrolyte interface for magnesium ions. The electrolyte does not contain halogens, does not contain complex additives, and has almost no corrosive effect on various current collectors; and has a low overpotential, high magnesium deposition-dissolution efficiency, and high oxidation stability. At the same time, the synthesis process is simple, the conditions are mild, the controllability is strong, the stability is good, the price is low, and it is more suitable for promotion and application in industrial production;

[0006] The present invention provides an electrolyte for a magnesium battery, comprising a magnesium salt and an amine organic solvent;

[0007] The general formula of the amine organic solvent is shown in formula (1):

[0008]

[0009] Wherein, R1, R2, and R3 are each independently selected from an alkyl group.

[0010] Preferably, the magnesium battery is a magnesium secondary battery;

[0011] The electrolyte is a halogen-free single-solvent electrolyte.

[0012] Preferably, the organic solvent in the electrolyte is only an amine organic solvent represented by formula (1);

[0013] The carbon number of the alkyl group selected from R1, R2 and R3 is C1 to C6.

[0014] Preferably, the magnesium salt includes one or more of magnesium trifluoromethanesulfonate, magnesium bis(trifluoromethanesulfonyl)imide, magnesium fluorosilicate, magnesium hexafluorophosphate, magnesium tetrafluoroborate, magnesium trifluoroacetate and magnesium sulfate;

[0015] The organic solvent in the electrolyte includes one or more amine organic solvents represented by formula (1).

[0016] Preferably, the amine organic solvent includes one or more of 2,2-dimethoxyethylamine, 2,2-diethoxyethylamine, 2,2-dimethoxy-1-propylamine, 2,2-diethoxy-1-propylamine, 3,3-dimethoxypropylamine, 3,3-diethoxypropylamine, 3-methoxy-3-ethoxypropylamine, 4,4-dimethoxybutylamine and 4,4-diethoxybutylamine.

[0017] Preferably, the concentration of magnesium salt in the electrolyte is 0.1 to 1.0 mol·L -1 .

[0018] The present invention provides a method for preparing an electrolyte for a magnesium battery as described in any one of the above technical solutions, comprising the following steps:

[0019] Under a protective atmosphere, magnesium salt and an amine organic solvent are mixed to obtain an electrolyte for a magnesium battery.

[0020] Preferably, the mixing time is 12 to 24 hours.

[0021] Preferably, the water content in the protective atmosphere is less than or equal to 0.1 ppm;

[0022] The oxygen content in the protective atmosphere is less than or equal to 0.1 ppm.

[0023] The present invention provides a magnesium secondary battery, comprising the electrolyte described in any one of the above technical solutions or the electrolyte prepared by the preparation method described in any one of the above technical solutions.

[0024] The present invention provides an electrolyte for a magnesium battery, comprising a magnesium salt and an amine organic solvent; the general formula of the amine organic solvent is shown in Formula (1). Compared with the prior art, the present invention believes that simple magnesium salt electrolyte systems are an important research direction, and the development of a rechargeable magnesium battery electrolyte that is halogen-free, has high oxidative stability, is inexpensive, and has a simple synthesis method is extremely urgent and important.

[0025] Based on this, the present invention creatively designed a simple magnesium salt electrolyte with a specific structural amine organic solvent. The halogen-free, single-solvent rechargeable magnesium battery electrolyte provided by the present invention does not contain halogen elements, thus avoiding corrosion of the current collector. Furthermore, the single-solvent system does not require the introduction of complex additives. Furthermore, the present invention uses a commercially available simple magnesium salt in an amine solvent. Through direct coordination between the amine solvent and the magnesium ions in the solvation shell, an organic-dominated interfacial film is formed on the surface of the magnesium negative electrode, promoting the formation of a magnesium-conducting SEI layer. This effectively reduces the overpotential (49mV), enhances oxidative stability (oxidative decomposition voltage 3.1V), and improves the magnesium deposition-dissolution efficiency (~100%).

[0026] The present invention utilizes direct coordination between an amine solvent and magnesium ions to form an organic-dominated interfacial film on the surface of the magnesium negative electrode. This film serves as a solid electrolyte interface for the magnesium ions. This electrolyte is halogen-free and contains no complex additives, exhibiting virtually no corrosion to various current collectors. Furthermore, it offers a low overpotential, high magnesium deposition and dissolution efficiency, and high oxidative stability. The present invention also provides a corresponding preparation method. This halogen-free, single-solvent rechargeable magnesium battery electrolyte utilizes low-cost raw materials, a simple preparation process, and requires only room-temperature reactions, making it more suitable for large-scale industrial production.

[0027] The experimental results show that the capacity of the halogen-free single-solvent rechargeable magnesium battery provided by the present invention is maintained at 56 mAhg at a rate of 1C. -1 , Coulombic efficiency is close to 100%, and the electrochemical performance is excellent. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is the linear sweep voltammogram of the magnesium battery electrolyte prepared in Example 1 of the present invention using stainless steel foil as the working electrode;

[0029] Figure 2 This is a coulombic efficiency diagram of magnesium deposition / dissolution of the magnesium battery electrolyte prepared in Example 1 of the present invention using stainless steel foil as the working electrode;

[0030] Figure 3 This is a voltage-time curve of the magnesium battery electrolyte prepared in Example 1 of the present invention in a Mg||Mg symmetrical battery;

[0031] Figure 4 This is the electrochemical impedance spectrum of the magnesium battery electrolyte prepared in Example 1 of the present invention in an SS||SS symmetrical battery;

[0032] Figure 5 This is the electrochemical impedance spectrum of the magnesium battery electrolyte prepared in Example 2 of the present invention in a SS||SS symmetrical battery;

[0033] Figure 6 This is a cycling performance diagram of the CuS||Mg full battery assembled in Example 3 of the present invention;

[0034] Figure 7 This is a cycle performance diagram of the Mo6S8||Mg full battery assembled in Example 4 of the present invention. DETAILED DESCRIPTION

[0035] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention rather than limiting the patent claims of the present invention.

[0036] All raw materials of the present invention are not particularly limited in their sources and can be purchased from the market or prepared according to conventional methods well known to those skilled in the art.

[0037] There is no particular limitation on the purity of all raw materials in the present invention. The present invention preferably uses analytically pure materials or materials with conventional purity in the field of magnesium secondary battery electrolyte preparation.

[0038] The present invention provides an electrolyte for a magnesium battery, comprising a magnesium salt and an amine organic solvent;

[0039] The general formula of the amine organic solvent is shown in formula (1):

[0040]

[0041] Wherein, R1, R2, and R3 are each independently selected from an alkyl group.

[0042] In the present invention, the magnesium battery is preferably a magnesium secondary battery, that is, a rechargeable magnesium battery.

[0043] In the present invention, the electrolyte is preferably a halogen-free single-solvent electrolyte.

[0044] Specifically, the electrosolvent refers to the electrolyte provided by the present invention containing only the amine organic solvent of the structure shown in formula (1) and no other solvents or organic solvents. In the electrolyte, the amine organic solvent of the structure shown in formula (1) can be one or more.

[0045] In the present invention, the carbon number of the alkyl group independently selected from R1, R2, and R3 is preferably C1 to C6, or C2 to C5, or C3 to C4.

[0046] In the present invention, the magnesium salt preferably includes one or more of magnesium trifluoromethanesulfonate, magnesium bis(trifluoromethanesulfonyl)imide, magnesium fluorosilicate, magnesium hexafluorophosphate, magnesium tetrafluoroborate, magnesium trifluoroacetate and magnesium sulfate, more preferably magnesium trifluoromethanesulfonate (Mg(CF3SO3)2), magnesium bis(trifluoromethanesulfonyl)imide (Mg(C7HF3NO4S)2), magnesium fluorosilicate (MgSiF6), magnesium hexafluorophosphate (Mg(PF6)2), magnesium tetrafluoroborate (Mg(BF4)2), magnesium trifluoroacetate (Mg(CF3COO)2) or magnesium sulfate (MgSO4).

[0047] In the present invention, the amine organic solvent preferably includes one or more of 2,2-dimethoxyethylamine, 2,2-diethoxyethylamine, 2,2-dimethoxy-1-propylamine, 2,2-diethoxy-1-propylamine, 3,3-dimethoxypropylamine, 3,3-diethoxypropylamine, 3-methoxy-3-ethoxypropylamine, 4,4-dimethoxybutylamine and 4,4-diethoxybutylamine, more preferably 2,2-dimethoxyethylamine, 2,2-diethoxyethylamine, 2,2-dimethoxy-1-propylamine, 2,2-diethoxy-1-propylamine, 3,3-dimethoxypropylamine, 3,3-diethoxypropylamine, 3-methoxy-3-ethoxypropylamine, 4,4-dimethoxybutylamine or 4,4-diethoxybutylamine.

[0048] In the present invention, the concentration of magnesium salt in the electrolyte is preferably 0.1 to 1.0 mol·L -1 , more preferably 0.3 to 0.8 mol·L -1 , more preferably 0.5 to 0.6 mol·L -1 .

[0049] The present invention provides a method for preparing an electrolyte for a magnesium battery as described in any one of the above technical solutions, comprising the following steps:

[0050] Under a protective atmosphere, magnesium salt and an amine organic solvent are mixed to obtain an electrolyte for a magnesium battery.

[0051] In the present invention, the mixing time is preferably 12 to 24 hours, more preferably 14 to 22 hours, and even more preferably 16 to 20 hours.

[0052] In the present invention, the water content in the protective atmosphere is preferably less than or equal to 0.1 ppm, more preferably less than or equal to 0.08 ppm, and even more preferably less than or equal to 0.05 ppm. Specifically, it can be 0.03 to 0.1 ppm.

[0053] In the present invention, the oxygen content in the protective atmosphere is preferably less than or equal to 0.1 ppm, more preferably less than or equal to 0.08 ppm, and even more preferably less than or equal to 0.05 ppm. Specifically, it can be 0.03 to 0.1 ppm.

[0054] The present invention provides a magnesium secondary battery, comprising the electrolyte described in any one of the above technical solutions or the electrolyte prepared by the preparation method described in any one of the above technical solutions.

[0055] The present invention is a complete and detailed overall technical solution that better ensures the composition and ratio of the electrolyte and further improves the comprehensive performance of the rechargeable magnesium battery electrolyte. The above-mentioned halogen-free single-solvent rechargeable magnesium battery electrolyte and its preparation method and application can specifically include the following contents:

[0056] A halogen-free single-solvent rechargeable magnesium battery electrolyte comprises a magnesium salt and a single amine organic solvent, wherein the single amine organic solvent has a general formula as shown in formula (1):

[0057]

[0058] In the above general formula, R1, R2, and R3 are alkyl groups.

[0059] Specifically, the alkyl chains of R1, R2, and R3 in the general formula (1) are independently C n H 2n+1 Indicates that 6≥n≥1.

[0060] Specifically, the magnesium salt is at least one or more of magnesium trifluoromethanesulfonate (Mg(CF3SO3)2), magnesium bis(trifluoromethanesulfonyl)imide (Mg(C7HF3NO4S)2), magnesium fluorosilicate (MgSiF6), magnesium hexafluorophosphate (Mg(PF6)2), magnesium tetrafluoroborate (Mg(BF4)2), magnesium trifluoroacetate (Mg(CF3COO)2), and magnesium sulfate (MgSO4).

[0061] Specifically, the single amine organic solvent is one or more of 2,2-dimethoxyethylamine, 2,2-diethoxyethylamine, 2,2-dimethoxy-1-propylamine, 2,2-diethoxy-1-propylamine, 3,3-dimethoxypropylamine, 3,3-diethoxypropylamine, 3-methoxy-3-ethoxypropylamine, 4,4-dimethoxybutylamine, 4,4-diethoxybutylamine, etc.

[0062] Specifically, the molar concentration of magnesium salt in the electrolyte is 0.1 to 1.0 mol L -1 .

[0063] The present invention also provides a method for preparing a halogen-free single-solvent rechargeable magnesium battery electrolyte as described in any of the above technical solutions, comprising: adding a magnesium salt to a single amine organic solvent under an inert atmosphere, and stirring at room temperature to obtain the magnesium battery electrolyte.

[0064] Specifically, the stirring time is 12-24 hours, and the water and oxygen contents of the inert atmosphere are both lower than 0.1 ppm.

[0065] The present invention also provides a rechargeable magnesium battery, comprising the halogen-free single-solvent rechargeable magnesium battery electrolyte described in any one of the above technical solutions.

[0066] The present invention provides a halogen-free, single-solvent rechargeable magnesium battery electrolyte, its preparation method, and its application. The present invention specifically designs a simple magnesium salt electrolyte with a specific structural amine organic solvent. This halogen-free, single-solvent rechargeable magnesium battery electrolyte is halogen-free, thus avoiding corrosion of the current collector. Furthermore, the single-solvent system does not require the introduction of complex additives. Furthermore, the present invention utilizes a commercially available simple magnesium salt in an amine solvent. Through direct coordination between the amine solvent and the magnesium ions in the solvation shell, an organic-dominated interfacial film is formed on the surface of the magnesium negative electrode, promoting the formation of a magnesium-conducting SEI layer. This effectively reduces the overpotential (49 mV), enhances oxidative stability (oxidative decomposition voltage 3.1 V), and improves magnesium deposition and dissolution efficiency (~100%).

[0067] The present invention utilizes direct coordination between an amine solvent and magnesium ions to form an organic-dominated interfacial film on the surface of the magnesium negative electrode. This film serves as a solid electrolyte interface for the magnesium ions. This electrolyte is halogen-free and contains no complex additives, exhibiting virtually no corrosion to various current collectors. Furthermore, it offers a low overpotential, high magnesium deposition and dissolution efficiency, and high oxidative stability. The present invention also provides a corresponding preparation method. This halogen-free, single-solvent rechargeable magnesium battery electrolyte utilizes low-cost raw materials, a simple preparation process, and requires only room-temperature reactions, making it more suitable for large-scale industrial production.

[0068] The experimental results show that the capacity of the halogen-free single-solvent rechargeable magnesium battery provided by the present invention is maintained at 56 mAhg at a rate of 1C. -1 , Coulombic efficiency is close to 100%, and the electrochemical performance is excellent.

[0069] To further illustrate the present invention, an electrolyte for a magnesium battery, a preparation method thereof, and a magnesium secondary battery provided by the present invention are described in detail below in conjunction with examples. However, it should be understood that these examples are implemented based on the technical solution of the present invention, and detailed implementation methods and specific operating processes are provided only to further illustrate the features and advantages of the present invention, rather than to limit the claims of the present invention. The scope of protection of the present invention is not limited to the following examples.

[0070] Example 1

[0071] This embodiment provides a method for preparing a magnesium battery electrolyte, the steps are as follows:

[0072] In a glove box filled with argon and with water and oxygen contents below 0.1 ppm, 0.2902 g of Mg(CF3SO3)2 was weighed and added to a reagent bottle containing 3 mL of dried 2,2-dimethoxyethylamine. The mixture was stirred at room temperature for 12 h to obtain a magnesium battery electrolyte with a magnesium ion concentration of 0.3 mol L -1 .

[0073] Taking the electrolyte prepared above as an example, the electrolyte was used, stainless steel foil was used as the working electrode, magnesium sheet was used as the counter electrode and reference electrode, and the separator was glass fiber. A button cell (CR2032) was assembled and linear sweep voltammetry was performed with a scan rate of 1 mV / s ( Figure 1 ).

[0074] See also Figure 1 , Figure 1 This is the linear sweep voltammogram of the magnesium battery electrolyte prepared in Example 1 of the present invention using stainless steel foil as the working electrode.

[0075] Using this electrolyte, stainless steel foil as the working electrode, magnesium sheet as the counter electrode and reference electrode, and glass fiber as the separator, button cells (CR2032) were assembled and magnesium deposition / dissolution cycle efficiency was tested at a current density of 0.5 mA cm -2 , the discharge time is 1h, and the charging end voltage is 1.2V ( Figure 2 ).

[0076] See also Figure 2 , Figure 2 This is a coulombic efficiency diagram of magnesium deposition / dissolution of the magnesium battery electrolyte prepared in Example 1 of the present invention using stainless steel foil as the working electrode.

[0077] like Figure 1 、 2 As shown, the electrochemical oxidation decomposition voltage of the magnesium battery electrolyte is 3.1V (vs.Mg / Mg 2+ ), indicating that it has good oxidation stability and can efficiently deposit / dissolve magnesium, with a deposition / dissolution efficiency of ~100%.

[0078] Using this electrolyte, magnesium sheets as working and counter electrodes, and glass fiber as separator, a symmetrical battery (CR2032) was assembled and polarization performance was tested at a current density of 0.5 mA cm -2 , time control 1h( Figure 3 ).

[0079] See also Figure 3 , Figure 3 This is a voltage-time curve of the magnesium battery electrolyte prepared in Example 1 of the present invention in a Mg||Mg symmetric battery.

[0080] like Figure 3 As shown, at a current density of 0.5 mA cm -2 When the electrolyte is quenched, the battery can be stably cycled for 300 h, with a stable polarization potential and an extremely low overpotential of 49 mV, indicating that the electrolyte has excellent stability for magnesium.

[0081] The conductivity of the electrolyte was tested using electrochemical impedance spectroscopy; stainless steel foil was used as the reference electrode, working electrode and counter electrode, the test voltage was 5mV, and the frequency range was 1MHz-0.01Hz ( Figure 4 ).

[0082] See also Figure 4 , Figure 4 This is the electrochemical impedance spectrum of the magnesium battery electrolyte prepared in Example 1 of the present invention in an SS||SS symmetrical battery.

[0083] like Figure 4 As shown, the ionic conductivity of the magnesium battery electrolyte is 0.78 mS cm -1 , the higher ionic conductivity indicates that Mg2+ Fast migration rate.

[0084] Example 2

[0085] In a glove box filled with argon and with water and oxygen contents below 0.1 ppm, 0.2902 g of Mg(CF3SO3)2 was weighed and added to a reagent bottle containing 3 mL of dried conventional ether solvent ethylene glycol dimethyl ether. The mixture was stirred at room temperature for 12 h to obtain a magnesium battery electrolyte with a magnesium ion concentration of 0.3 mol L -1 .

[0086] The conductivity of the electrolyte prepared above was tested by electrochemical impedance spectroscopy, with stainless steel foil as the reference electrode, working electrode and counter electrode, the test voltage was 5mV, and the frequency range was 1MHz-0.01Hz ( Figure 5 ).

[0087] See also Figure 5 , Figure 5 This is the electrochemical impedance spectrum of the magnesium battery electrolyte prepared in Example 2 of the present invention in an SS||SS symmetrical battery.

[0088] like Figure 5 As shown in the figure, the ionic conductivity of the magnesium battery electrolyte prepared in Example 2 is much lower than that of the magnesium battery electrolyte prepared in Example 1, which proves that amine solvents are more conducive to the Mg 2+ Rapid migration.

[0089] Example 3

[0090] The magnesium battery electrolyte prepared in Example 1 was used to assemble a full battery with magnesium sheet as the negative electrode, CuS as the positive electrode, and glass fiber as the separator, and a constant current charge and discharge test was performed with a voltage range of 0.2 to 2.2 V.

[0091] See also Figure 6 , Figure 6 This is a cycling performance diagram of the CuS||Mg full battery assembled in Example 3 of the present invention.

[0092] like Figure 6 As shown, the CuS||Mg full battery is at 0.2Ag -1 The discharge capacity of the first cycle at the same rate is 201 mAh g -1 , and the discharge capacity can be maintained at 87mAhg after 50 cycles -1 .

[0093] Example 4

[0094] The magnesium battery electrolyte prepared in Example 1 was used to assemble a full battery with magnesium sheet as the negative electrode, Mo6S8 as the positive electrode, and glass fiber as the separator, and a constant current charge and discharge test was performed with a voltage range of 0.2 to 2.2 V.

[0095] See also Figure 7 , Figure 7 This is a cycle performance diagram of the Mo6S8||Mg full battery assembled in Example 4 of the present invention.

[0096] like Figure 7 As shown in the figure, the prepared magnesium metal full battery has a high initial specific capacity (133 mAh g -1 ), the capacity is maintained at 56 mAh g after 50 cycles at 1C rate. -1 There is no obvious capacity decay, and the coulombic efficiency remains almost 100%, which fully demonstrates that the electrolyte has excellent electrochemical performance when used in magnesium metal full batteries.

[0097] The above describes in detail the halogen-free, single-solvent rechargeable magnesium battery electrolyte provided by the present invention, its preparation method, and its application. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above examples is intended only to facilitate understanding of the methods and core concepts of the present invention, including the best mode, and to enable any person skilled in the art to practice the present invention, including the manufacture and use of any device or system, and the implementation of any combined method. It should be noted that, without departing from the principles of the present invention, a person skilled in the art may make various improvements and modifications to the present invention, and such improvements and modifications fall within the scope of protection of the claims. The scope of patent protection for the present invention is defined by the claims and may include other embodiments that may be conceived by a person skilled in the art. If these other embodiments have structural elements similar to those described in the claims, or if they include equivalent structural elements that are not substantially different from the claims, then these other embodiments are also included within the scope of the claims.

Claims

1. An electrolyte for a magnesium battery, characterized in that: Including magnesium salts and amine organic solvents; The general formula of the amine organic solvent is shown in formula (1): Wherein, R1, R2, and R3 are each independently selected from an alkyl group.

2. The electrolyte according to claim 1, characterized in that The magnesium battery is a magnesium secondary battery; The electrolyte is a halogen-free single-solvent electrolyte.

3. The electrolyte according to claim 1, characterized in that The organic solvent in the electrolyte is only an amine organic solvent represented by formula (1); The carbon number of the alkyl group selected from R1, R2 and R3 is C1 to C6.

4. The electrolyte according to claim 1, characterized in that The magnesium salt includes one or more of magnesium trifluoromethanesulfonate, magnesium bis(trifluoromethanesulfonyl)imide, magnesium fluorosilicate, magnesium hexafluorophosphate, magnesium tetrafluoroborate, magnesium trifluoroacetate and magnesium sulfate; The organic solvent in the electrolyte includes one or more amine organic solvents represented by formula (1).

5. The electrolyte according to claim 1, characterized in that The amine organic solvent includes one or more of 2,2-dimethoxyethylamine, 2,2-diethoxyethylamine, 2,2-dimethoxy-1-propylamine, 2,2-diethoxy-1-propylamine, 3,3-dimethoxypropylamine, 3,3-diethoxypropylamine, 3-methoxy-3-ethoxypropylamine, 4,4-dimethoxybutylamine and 4,4-diethoxybutylamine.

6. The electrolyte according to claim 1, characterized in that The concentration of magnesium salt in the electrolyte is 0.1-1.0 mol·L -1 .

7. A method for preparing an electrolyte for a magnesium battery according to any one of claims 1 to 6, characterized in that: The following steps are involved: Under a protective atmosphere, magnesium salt and an amine organic solvent are mixed to obtain an electrolyte for a magnesium battery.

8. The preparation method according to claim 7, characterized in that The mixing time is 12 to 24 hours.

9. The preparation method according to claim 7, characterized in that The water content in the protective atmosphere is less than or equal to 0.1 ppm; The oxygen content in the protective atmosphere is less than or equal to 0.1 ppm.

10. A magnesium secondary battery, characterized in that: The invention comprises the electrolyte according to any one of claims 1 to 5 or the electrolyte prepared by the preparation method according to any one of claims 7 to 9.

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