Manganese cluster ion complexing electrolyte and application thereof in energy storage device

Abstract

The invention belongs to the technical field of manganese metal batteries, and relates to a manganese cluster ion complexing electrolyte and application thereof in an energy storage device. The invention discloses a manganese cluster ion complexing electrolyte which is prepared by dissolving manganese halide, Lewis acid and manganese salt in a non-aqueous solvent, manganese ions in the manganese cluster ion complexing electrolyte form binuclear manganese cluster ions through bridged bonds constructed by halide ions. The manganese cluster ion complexing electrolyte is used for carrying out manganese metal deposition and stripping at the temperature of 40 DEG C below zero to 60 DEG C; and the electrochemical energy storage device containing the manganese cluster ion complexing electrolyte has excellent electrochemical performance, can normally work at the temperature of-40 to 60 DEG C, and has a good application prospect.

Description

Technical Field

[0001] The present invention belongs to the technical field of manganese metal batteries, and relates to a manganese cluster ion complex electrolyte and its application in energy storage devices. Background Art

[0002] In recent years, electrochemical energy storage devices have achieved leapfrog development globally. Lithium-ion batteries are an important part of them. However, due to the high dependence on scarce resources such as lithium and cobalt, the cost fluctuates violently, and sustainable development faces severe challenges. Developing high-performance secondary batteries based on abundant elements such as sodium, potassium, calcium, magnesium, aluminum, zinc, manganese or even non-metals has become an important breakthrough direction. Among them, metals such as sodium, potassium, and calcium face double challenges of cost and safety when used as metal anodes due to their high reactivity with air and water; although non-metal batteries have achieved extremely low storage, assembly costs and inherent safety by using aqueous electrolytes, they are limited by the thermodynamic window of water and generally have low working voltages. In contrast, multivalent metals such as magnesium, aluminum, zinc, and manganese have both air stability and low working potentials, showing the potential for large-scale application. Among these materials, manganese metal stands out due to its high crust abundance, high annual output, and low cost.

[0003] However, the violent side reaction between metallic manganese and water leads to problems such as poor stability and short cycle life in aqueous manganese metal batteries. Although the organic electrolyte system can theoretically completely avoid the side reaction problems of aqueous electrolytes, manganese ions (83 pm) have a significantly higher charge density than monovalent ions (Li+, Na+, K+), and are prone to form strong coordination bonds with solvent oxygen atoms, resulting in too high deposition / stripping overpotential (>800 mV). Therefore, achieving reversible and efficient deposition / stripping of metallic manganese has become the core challenge in developing high-performance manganese metal batteries. Summary of the Invention

[0004] The object of the present invention is to address the above problems existing in the prior art, and propose a manganese cluster ion complex electrolyte that can achieve stable high Coulomb efficiency and low overpotential for manganese metal deposition / stripping. The energy storage device constructed based on the manganese cluster ion complex electrolyte also has good performance.

[0005] One object of the present invention is achieved by the following technical solutions:

[0006] A manganese cluster ion complex electrolyte is prepared by dissolving manganese salts of manganese halide, Lewis acid, and non-manganese halide with a molar ratio of 1:(0.1-5):(0.1-5) in a non-aqueous solvent;

[0007] In the manganese cluster ion complex electrolyte, manganese ions form binuclear manganese cluster ions through bridge bonds constructed by halogen ions.

[0008] Preferably, the molar ratio of manganese in the manganese halide, Lewis acid, and non-manganese halide is 1:(0.5 - 1.6):(0.5 - 1.6).

[0009] More preferably, the molar ratio of manganese in the manganese halide, Lewis acid, and manganese salt of non-manganese halide is 1:(0.52 - 1.18):(0.52 - 1.18).

[0010] Even more preferably, the molar ratio of manganese in the manganese halide, Lewis acid, and manganese salt of non-manganese halide is 1:1:1.

[0011] Preferably, the manganese halide is one or more of manganese fluoride (MnF2), manganese chloride (MnCl2), manganese bromide (MnBr2), and manganese iodide (MnI2).

[0012] Preferably, the Lewis acid includes, but is not limited to, one or more of aluminum fluoride, aluminum chloride, aluminum bromide, aluminum iodide, boron fluoride, boron chloride, boron bromide, boron iodide, gallium fluoride, gallium chloride, gallium bromide, gallium iodide, indium fluoride, indium chloride, indium bromide, indium iodide, antimony fluoride, antimony chloride, antimony bromide, antimony iodide, aluminum bis(trifluoromethanesulfonyl)imide (Al(TFSI)3), aluminum bis(fluorosulfonyl)imide (Al(FSI)3), and aluminum trifluoromethanesulfonate (Al(OTf)3).

[0013] Preferably, the manganese salt of non-manganese halide includes, but is not limited to, one or more of manganese bis(trifluoromethanesulfonyl)imide (Mn(TFSI)2), manganese bis(fluorosulfonyl)imide (Mn(FSI)2), manganese trifluoromethanesulfonate (Mn(OTf)2), manganese perchlorate (Mn(ClO4)2), manganese nitrate (Mn(NO3)2), and manganese acetate (Mn(Ac)2).

[0014] Preferably, in the manganese cluster ion complex electrolyte, the concentration of manganese halide is 0.05 - 0.15 mmol / mL.

[0015] More preferably, in the manganese cluster ion complex electrolyte, the concentration of manganese halide is 0.08 - 0.13 mmol / mL.

[0016] Preferably, the non-aqueous solvent includes, but is not limited to, one or more of 1,3-dioxolane (DOL), 1,4-dioxane (1,4-DOX), 1,3-dioxane (1,3-DOX), ethylene glycol dimethyl ether (DME), diethylene glycol dimethyl ether (Diglyme), triethylene glycol dimethyl ether (Triglyme), tetraethylene glycol dimethyl ether (Tetraglyme), dimethyl sulfone, methyl ethyl sulfone, sulfolane, and tetrahydrofuran (THF).

[0017] More preferably, the non-aqueous solvent is sulfolane and one selected from 1,3-dioxolane (DOL), 1,4-dioxane (1,4-DOX), 1,3-dioxane (1,3-DOX), ethylene glycol dimethyl ether (DME), diethylene glycol dimethyl ether (Diglyme), triethylene glycol dimethyl ether (Triglyme), tetraethylene glycol dimethyl ether (Tetraglyme), dimethyl sulfone, methyl ethyl sulfone, tetrahydrofuran (THF).

[0018] Even more preferably, the volume ratio of the two in the non-aqueous solvent is 1:(1.1 - 3.5).

[0019] Preferably, the manganese cluster ion complex electrolyte further contains an additive.

[0020] More preferably, the additive includes, but is not limited to, one or more of bis(trifluoromethanesulfonyl)imide salts, bis(fluorosulfonyl)imide salts, trifluoromethanesulfonates, perchlorates, nitrates, acetates, etc. of symmetric or asymmetric quaternary ammonium cations such as tetramethylammonium, tetraethylammonium, tetrapropylammonium, etc.

[0021] More preferably, the manganese cluster ion complex electrolyte is prepared by dissolving manganese halide, Lewis acid, manganese salt of non-halogenated manganese, and additive with a molar ratio of 1:(0.52 - 1.18):(0.52 - 1.18):(1.80 - 4.25) in a non-aqueous solvent.

[0022] Preferably, the manganese cluster ion complex electrolyte remains liquid at -40 to 60 °C.

[0023] Preferably, reversible deposition and stripping of metallic manganese are achieved within the range of -40 to 60 °C for the manganese cluster ion complex electrolyte.

[0024] Preferably, the ionic conductivity of the manganese cluster ion complex electrolyte at -40 to 60 °C is 0.26 to 5.66 mS / cm.

[0025] More preferably, the ionic conductivity of the manganese cluster ion complex electrolyte at 20 to 60 °C is 3.63 to 5.66 mS / cm.

[0026] The second object of the present invention is achieved by the following technical solutions:

[0027] A manganese metal electrochemical energy storage device, which includes a manganese cluster ion complex electrolyte.

[0028] Preferably, the manganese metal electrochemical energy storage device includes, but is not limited to, one or more of manganese metal capacitors, secondary batteries, primary batteries.

[0029] Preferably, the manganese metal electrochemical energy storage device further includes a positive electrode and a negative electrode.

[0030] More preferably, the active component of the positive electrode of the manganese metal electrochemical energy storage device includes, but is not limited to, one or more of a polymer containing a carbonyl group and / or an imine group, an organic small molecule, activated carbon (AC), a Prussian blue analogue, a manganese oxide, and a vanadium oxide.

[0031] More preferably, the active component of the negative electrode of the manganese metal electrochemical energy storage device is metallic manganese.

[0032] Preferably, the manganese metal electrochemical energy storage device operates stably at a temperature of -40 to 60 °C.

[0033] Preferably, the manganese metal electrochemical energy storage device deposits / strips 1 to 2 mAh at a current of 0.1 to 10 mA, and the average potential at room temperature is as low as below 200 mV.

[0034] Preferably, the manganese metal electrochemical energy storage device deposits / strips 1 to 2 mAh at a current of 0.1 to 10 mA, and the average potential at -40 °C is as low as below 700 mV.

[0035] The third object of the present invention is achieved by the following technical solutions:

[0036] A manganese metal capacitor includes a manganese cluster ion complex electrolyte.

[0037] Preferably, the manganese metal capacitor further includes a negative electrode with an active component of metallic manganese and a positive electrode with an active component of activated carbon.

[0038] More preferably, the metallic manganese is derived from one or more of electrolytic manganese, manganese powder, and manganese sheet.

[0039] Preferably, the manganese metal capacitor deposits / strips 0.1 to 2 mAh at a current of 1 to 10 mA, the average potential at room temperature is < 600 mV, and the average potential at -40 °C is < 700 mV.

[0040] Preferably, the manganese metal capacitor deposits / strips 2 mAh at a current of 1 to 10 mA, and the average potential at room temperature is < 600 mV.

[0041] More preferably, the manganese metal capacitor deposits / strips 2 mAh at a current of 1 to 5 mA, and the average potential at room temperature is < 300 mV.

[0042] More preferably, the manganese metal capacitor deposits / strips 2 mAh at a current of 1 mA, and the average potential at room temperature is < 200 mV.

[0043] Preferably, when the manganese metal capacitor deposits / strips 0.1 mAh at a current of 0.1 - 1 mA, the average potential is < 250 mV at room temperature.

[0044] More preferably, at room temperature, when the manganese metal capacitor deposits / strips 0.1 mAh at a current of 0.1 - 1 mA, the average potential is < 250 mV; when the manganese metal capacitor deposits / strips 0.1 mAh at a current of 0.1 mA, the average potential is < 200 mV.

[0045] Preferably, when the manganese metal capacitor deposits / strips 0.1 mAh at a current of 0.1 - 1 mA, the average potential is < 700 mV at - 40 °C.

[0046] More preferably, at - 40 °C, when the manganese metal capacitor deposits / strips 0.1 mAh at a current of 0.1 - 1 mA, the average potential is < 700 mV; when the manganese metal capacitor deposits / strips 0.1 mAh at a current of 0.1 mA, the average potential is < 300 mV.

[0047] The fourth object of the present invention is achieved by the following technical solutions:

[0048] A manganese metal secondary battery, which includes a manganese cluster ion complex electrolyte.

[0049] Preferably, the manganese metal secondary battery includes one or more of, but is not limited to, button cells, Swagelok two - electrode cells.

[0050] Preferably, the manganese metal secondary battery includes a positive electrode, a negative electrode, and a manganese cluster ion complex electrolyte.

[0051] Preferably, the active components of the positive electrode include one or more of, but are not limited to, polymers and organic small molecules containing carbonyl and / or imine groups, Prussian blue analogs, manganese oxides, vanadium oxides. Preferably, the active component of the negative electrode is metallic manganese, and the metallic manganese is derived from one or more of electrolytic manganese, manganese powder, and manganese sheets.

[0052] Preferably, the manganese metal secondary battery operates stably at a temperature of - 30 - 60 °C, the Coulomb efficiency is above 99%, and the specific capacity decay is < 35%.

[0053] Preferably, the manganese metal secondary battery operates stably at room temperature for 6000 cycles, and the Coulomb efficiency > 99%.

[0054] Preferably, the manganese metal secondary battery operates stably at high temperature (60 °C) and low temperature (- 30 °C) for 80 cycles, and the Coulomb efficiency is > 99% in both cases.

[0055] Preferably, the average working voltage of the manganese metal secondary battery is 1.1 - 1.7V.

[0056] Compared with the prior art, the present invention has the following beneficial effects:

[0057] 1. The manganese cluster ion complex electrolyte of the present invention deposits and strips manganese metal with high coulombic efficiency and low overpotential.

[0058] 2. The manganese cluster ion complex electrolyte of the present invention has high ionic conductivity in a wide temperature range (-40 - 60°C), and reversible deposition and stripping of metallic manganese are achieved within this wide temperature range.

[0059] 3. The manganese cluster ion complex electrolyte of the present invention supports stable operation at high current densities and also provides a key path for realizing high-voltage batteries.

[0060] 4. The electrochemical energy storage device containing the manganese cluster ion complex electrolyte of the present invention has excellent electrochemical performance and can operate normally at temperatures from -40 to 60°C, expanding the application fields.

[0061] 5. The coulombic efficiency of the electrochemical energy storage device containing the manganese cluster ion complex electrolyte of the present invention reaches more than 99%, and the specific capacity shows no significant attenuation.

[0062] 6. The manganese metal capacitor (button-type manganese-manganese symmetric battery) containing the manganese cluster ion complex electrolyte of the present invention deposits / strips 0.1 mAh at a current of 0.1 mA and can operate stably at room temperature for at least 500 hours, and its overpotential can be less than 200 mV.

[0063] 7. The secondary battery containing the manganese cluster ion complex electrolyte of the present invention operates stably at -30 to 60°C, the coulombic efficiency remains at ~100%, and the specific capacity shows no significant attenuation. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 It is the cyclic voltammogram of the manganese cluster ion complex electrolyte of Example 1 of the present invention under a Swagelok three-electrode system and the optical photo of the manganese cluster ion complex electrolyte;

[0065] Figure 2 It is the cross-section (2a), planar scanning electron microscope image and optical photo (2b) of the metallic manganese deposited on a stainless steel substrate using the manganese cluster ion complex electrolyte of Example 1 of the present invention;

[0066] Figure 3This is the room-temperature cycling test chart (3a) and the corresponding charge-discharge curves (3b) of the coin-type Mn-Mn symmetric battery in Example 1 of the present invention, the room-temperature rate performance test chart (3c) and the corresponding charge-discharge curves (3d) of the coin-type Mn-Mn symmetric battery, the rate performance test chart (3e) of the coin-type Mn-Mn symmetric battery at -40 °C, and the optical photo (3f) of the manganese cluster ion complex electrolyte at -40 °C;

[0067] Figure 4 This is the room-temperature cycling test chart (4a) and the corresponding charge-discharge curves (4b) of the secondary battery in Example 1 of the present invention, and the cycling tests (4c) and the corresponding charge-discharge curves (4d) of the secondary battery at -30 °C and 60 °C;

[0068] Figure 5 This is the room-temperature cycling test chart (5a) of the manganese metal capacitor using Example 2 of the present invention

[0069] and the corresponding charge-discharge curves (5b);

[0070] Figure 6 This is the cyclic voltammogram of the manganese cluster ion complex electrolyte in Example 3 of the present invention under a Swagelok three-electrode;

[0071] Figure 7 This is the long-term stability test chart (7a) and the corresponding charge-discharge curves (7b) of the coin-type Mn-Mn symmetric battery in Example 3 of the present invention, the room-temperature rate performance test chart (7c) and the corresponding charge-discharge curves (7d);

[0072] Figure 8 This is the room-temperature rate performance test chart (8a) and the corresponding charge-discharge curves (8b) of the secondary battery in Example 3 of the present invention;

[0073] Figure 9 This is the room-temperature cycling test chart (9a) and the corresponding charge-discharge curves (9b) of the secondary battery in Example 4 of the present invention;

[0074] Figure 10 This is the cyclic voltammogram of the manganese cluster ion complex electrolyte in Example 5 of the present invention under a Swagelok three-electrode;

[0075] Figure 11 This is the room-temperature cycling test chart (11a) and the corresponding charge-discharge curves (11b) of the secondary battery in Example 5 of the present invention;

[0076] Figure 12 This is the room-temperature cycling test chart of the secondary battery at high current in Example 5 of the present invention;

[0077] Figure 13 This is the long-term stability test chart (13a) and the corresponding charge-discharge curves (13b) of the coin-type Mn-Mn symmetric battery in Example 6 of the present invention;

[0078] Figure 14 This is the room temperature cycling performance test chart (14a) and the corresponding charge-discharge curves (14b), and the energy dispersive spectroscopy results (14c) of the secondary battery in Example 6 of the present invention;

[0079] Figure 15 This is the high current test chart (15a) and the corresponding charge-discharge curves (15b) of the coin-type manganese-manganese symmetric battery in Example 7 of the present invention;

[0080] Figure 16 This is the typical charge-discharge curve of the secondary battery in Example 8 of the present invention;

[0081] Figure 17 This is the cyclic voltammogram (17a) and the manganese deposition / stripping test chart (17b) of the non-manganese cluster ion complex electrolyte under Swagelok three electrodes in Comparative Example 1 of the present invention;

[0082] Figure 18 This is the cyclic stability test chart (17a) and the corresponding charge-discharge curves (18b) of the coin-type asymmetric battery in Comparative Example 2 of the present invention;

[0083] Figure 19 This is the room temperature cycling test chart (19a) and the corresponding charge-discharge curves (19b) of the secondary battery in Comparative Example 3 of the present invention; and the optical photograph (19c) of the electrolyte in this comparative example after long-term storage. Detailed implementation manners

[0084] The technical solutions of the present invention will be further described and illustrated below through specific examples. It should be understood that the specific examples described here are only used to help understand the present invention and are not used for specific limitations of the present invention.

[0085] If there is no special description, the raw materials used in the embodiments of the present invention are all common raw materials in the art, and the methods used in the embodiments are all conventional methods in the art.

[0086] Example 1

[0087] Manganese cluster ion complex electrolyte:

[0088] It is obtained by completely dissolving 0.6 mmol of MnCl2, 0.6 mmol of AlCl3, and 0.6 mmol of Mn(TFSI)2 in 5 mL of a mixed solution of tetrahydrofuran and sulfolane with a volume ratio of 3:2.

[0089] The conductivity of the manganese cluster ion complex electrolyte was tested, and at -40 °C, 20 °C, and 60 °C, the conductivities were 0.26 mS / cm, 3.63 mS / cm, and 5.66 mS / cm, respectively.

[0090] The positive electrode material is a conductive polymer poly(benzimidazole benzophenanthroline) (BBL) containing carbonyl and imino groups.

[0091] Negative electrode material:

[0092] Put metallic manganese powder into a ball milling tank, evacuate the air, and ball mill at a speed of 900 revolutions per minute for 12 hours; in an argon-filled glove box, mix the ball-milled metallic manganese powder with acetylene black and polyvinylidene fluoride in a mass ratio of 90:5:5, add N-methylpyrrolidone to make a slurry, coat the slurry on carbon cloth, and place it at 110 °C to dry completely for standby. The loading amount of metallic manganese powder in the negative electrode material is greater than 40 mg / cm 2 .

[0093] Performance test 1-1:

[0094] Test the manganese cluster ion complex electrolyte:

[0095] In the manganese cluster ion complex electrolyte, the working electrode is a tungsten rod, the counter electrode is activated carbon and a tungsten rod, the reference electrode is a silver rod, and the scanning rate is 20 mV / s; the test results of the cyclic voltammetry curve (CV) under Swagelok three electrodes are as Figure 1 shown. The CV curve is a typical metal deposition / stripping type and has a low overpotential (less than 200 mV), indicating that the manganese cluster ion complex electrolyte of this embodiment can effectively deposit and strip manganese metal.

[0096] Performance test 1-2:

[0097] Deposit manganese metal using the manganese cluster ion complex electrolyte:

[0098] In the manganese cluster ion complex electrolyte, use a button battery mold to assemble a button-type asymmetric battery to deposit metallic manganese on a stainless steel substrate. The steps are as follows: Take a stainless steel sheet with a diameter of 12 mm and place it in the center of the positive electrode shell of the button battery. Put in a glass fiber separator, and drop an appropriate amount of the electrolyte of this embodiment on it to fully wet the separator. Subsequently, add a piece of electrolytic manganese sheet with an area of about 1 cm 2 (the smooth side faces the separator) in the center of the separator, drop a small amount of electrolyte on the manganese sheet, cover a button battery gasket, and then cover the negative electrode shell. Finally, place the battery in a hydraulic press for hydraulic sealing to obtain the button-type asymmetric battery for testing. The whole assembly process is carried out in an argon-filled glove box. After taking out the button-type asymmetric battery, use the stainless steel side as the working electrode, and carry out the process of discharging and depositing metallic manganese on the battery test system. The discharging current is 0.5 mA and the capacity is 10 mAh.

[0099] Observe the stainless steel on which manganese metal is deposited with a scanning electron microscope. Its cross-section and plane are as Figure 2 shown.Figure 2 The significant manganese signal in the cross-sectional image of a indicates the successful deposition of metallic manganese. Figure 2 A dense manganese deposition layer was observed in the planar image of b, and a shiny manganese metal deposition layer was observed in the optical photograph in the upper left corner.

[0100] Performance tests 1-3:

[0101] Assemble a coin-type manganese / manganese symmetric battery: The assembly process is similar to that of the coin-type asymmetric battery in Performance tests 1-2, except that the stainless-steel sheet is replaced with an electrolytic manganese sheet and no spacer is used.

[0102] The coin-type manganese / manganese symmetric battery deposits / strips 0.1 mAh at a current of 0.1 mA. The room-temperature cycling test results are shown in 3a, and it can operate stably for at least 500 hours; partial charge-discharge curves are as Figure 3 shown in b, and its overpotential is always less than 200 mV; this indicates that the manganese cluster ion complex electrolyte of this example has good room-temperature cycling stability.

[0103] Performance tests 1-4:

[0104] Deposit / strip 2 mAh from the coin-type manganese / manganese symmetric battery at currents of 1 mA, 2 mA, 3 mA, 4 mA, 5 mA, 6 mA, 7 mA, and 8 mA respectively. The room-temperature rate performance results are as Figure 3 shown in c, indicating that the electrolyte prepared in this example can work stably at various current densities; the charge-discharge curves are as Figure 3 shown in d. At a current of 1 mA, the average deposition / stripping potential is less than 200 mV. Even when the current increases to 8 mA, the average deposition / stripping potential is still less than 600 mV, indicating that the manganese cluster ion complex electrolyte of this example supports operation at high current densities.

[0105] Performance tests 1-5:

[0106] Deposit / strip 0.1 mAh from the coin-type manganese / manganese symmetric battery at currents of 0.1 mA, 0.2 mA, 0.5 mA, and 1.0 mA respectively. The rate performance results at -40 °C are shown in 3e. At a current of 0.1 mA, the average potential is less than 300 mV. Even at 1 mA, the average potential is less than 700 mV. At the same time, as Figure 3 shown in f, the manganese cluster ion complex electrolyte prepared in this example remains liquid at -40 °C, indicating its good low-temperature resistance.

[0107] Performance tests 1-6:

[0108] Assemble the BBL / Mn secondary battery using a Swagelok two - electrode cell. The positive current collector is a tungsten rod, and the negative current collector is a stainless - steel rod, a stainless - steel spring, and a stainless - steel gasket. The detailed steps are as follows: First, use a nut to tightly screw the tungsten rod onto the plastic housing. Place a BBL electrode sheet on the end face of the tungsten rod, cover it with a glass fiber separator, and drop an appropriate amount of the electrolyte in this embodiment to fully soak it. Add a self - made manganese negative electrode (with the manganese powder side facing the separator), supplement a small amount of electrolyte, then sequentially place the stainless - steel gasket, stainless - steel spring, and stainless - steel rod. Finally, use a nut to tightly screw the plastic housing and the stainless - steel rod. The entire assembly process is carried out in an argon - filled glove box.

[0109] Perform constant - current charge - discharge (GCD) tests at room temperature on the assembled BBL / Mn secondary battery. The room - temperature cycling performance and charge - discharge curves are as Figure 4 shown in a, 4b. This secondary battery operates stably for 6000 cycles, and the Coulombic efficiency always remains at about 100%; indicating that this BBL / Mn secondary battery has good stability.

[0110] Performance tests 1 - 7:

[0111] Perform high - temperature (60 °C) and low - temperature (-30 °C) GCD tests on the BBL / Mn secondary battery. The cycling performance and charge - discharge curves are as Figure 4 shown in c, 4d. After stabilization, the Coulombic efficiency always remains at about 100%, and the battery can still operate stably under high - temperature and low - temperature conditions, indicating that it has good wide - temperature adaptability.

[0112] In this embodiment, the charge carriers on the positive electrode side are AlCl 2+ , and manganese metal deposition / stripping occurs at the negative electrode.

[0113] Example 2

[0114] Performance test 2 - 1:

[0115] Assemble the AC / Mn capacitor: The assembly process is the same as that in performance tests 1 - 6, only replacing the BBL electrode sheet with an activated carbon (AC) electrode sheet.

[0116] Perform constant - current charge - discharge (GCD) tests at room temperature. The room - temperature cycling performance and charge - discharge curves are as Figure 5 shown in a, 5b. The charge - discharge curves are basically straight lines, which conform to the typical characteristics of a capacitor. After cycling 100 times at a current density of 0.1 A / g, the specific capacity is 45.5 mAh / g. Then, switch to a current density of 1 A / g and continue cycling 1000 times. The specific capacity is 32.5 mAh / g (the specific capacity is calculated based on the mass of the activated carbon). The test results show that the AC / Mn capacitor assembled in this embodiment has good stability and rate performance.

[0117] Compared with Example 1, the difference is that the cathode material is activated carbon AC.

[0118] Example 3

[0119] Manganese cluster ion complex electrolyte:

[0120] It is obtained by completely dissolving 0.6 mmol of MnCl2, 0.6 mmol of AlCl3, and 0.6 mmol of Mn(TFSI)2 in 5 mL of sulfolane.

[0121] The cathode material is polytriphenylamine (PTPAn).

[0122] Anode material:

[0123] Put the metallic manganese powder into the ball milling tank, evacuate it, and ball mill it at a speed of 900 revolutions per minute for 12 hours; in the argon-filled glove box, mix the ball-milled metallic manganese powder with acetylene black and polyvinylidene fluoride according to a mass ratio of 90:5:5, add N-methylpyrrolidone to make a slurry, coat the slurry on the carbon cloth, and place it at 110 °C to dry completely for standby. The loading amount of metallic manganese powder in the anode material is greater than 40 mg / cm 2 .

[0124] Performance test 3-1:

[0125] In the manganese cluster ion complex electrolyte, the working electrode is a tungsten rod, the counter electrode is activated carbon and a tungsten rod, the reference electrode is a silver rod, and the scanning rate is 20 mV / s; the cyclic voltammetry (CV) test results under Swagelok three electrodes are as Figure 6 shown. The CV curve is a typical metal deposition / stripping type and has a low overpotential (less than 200 mV), indicating that the manganese cluster ion complex electrolyte of this example can effectively deposit and strip manganese metal.

[0126] Performance test 3-2:

[0127] Assemble a button-type manganese / manganese symmetric battery. The assembly process is the same as that in Performance Test 1-3, only replacing the electrolyte with the electrolyte in this example.

[0128] The button-type manganese / manganese symmetric battery deposits / strips 0.1 mAh at a current of 0.1 mA. The room temperature cycle test results are as shown in 7a, and it can operate stably for at least 500 hours; some charge-discharge curves are as Figure 7 shown in b, and its overpotential is always less than 200 mV; it shows that the manganese cluster ion complex electrolyte of this example has good room temperature stability.

[0129] Performance test 3-3:

[0130] Deposit / strip 1 mAh from the button-type manganese / manganese symmetric battery at a current of 0.1 mA. The room temperature rate performance results are asFigure 7 As shown in c, it shows that the electrolyte prepared in this example can work stably at various current densities; the charge-discharge curve is as Figure 7 shown in d. At a current of 0.1 mA, the average potential is close to 100 mV, and even at 1 mA, the average potential is less than 250 mV, indicating its good rate performance.

[0131] Performance Test 3-4:

[0132] Assemble the PTPAn / Mn secondary battery. The assembly process is the same as that described in Performance Test 1-6, only replacing the positive electrode sheet and the electrolyte with the PTPAn electrode sheet and the electrolyte in this example.

[0133] Perform constant current charge-discharge (GCD) tests on the PTPAn / Mn secondary battery at room temperature. The room temperature cycle performance and charge-discharge curves are as Figure 8 shown in a and 8b. At 0.1 A / g, the specific capacity after stabilization is 49.6 mAh / g. After sequentially switching from 0.1 - 0.15 - 0.2 - 0.25 - 0.3 to 0.3 A / g, the specific capacity is 35.2 mAh / g, showing good rate performance; according to the charge-discharge curve, the average working voltage is ~1.7 V, indicating that the PTPAn / Mn secondary battery in this example has the potential to assemble high-voltage batteries.

[0134] The carrier on the positive electrode side in this example is bis(trifluoromethanesulfonyl)imide anion (TFSI - ) and Al(TFSI)3Cl - , and manganese metal deposition / stripping occurs at the negative electrode.

[0135] Example 4

[0136] Manganese cluster ion complex electrolyte:

[0137] It is obtained by completely dissolving 0.6 mmol of MnCl2, 0.6 mmol of AlCl3, 0.6 mmol of Mn(TFSI)2, and 1.2 mmol of bis(trifluoromethanesulfonyl)imide salt of tetramethylammonium in 5 mL of a mixture of tetrahydrofuran and sulfolane with a volume ratio of 3:2.

[0138] The positive electrode material is a Prussian blue analogue material (TBA).

[0139] Negative electrode material:

[0140] Place the metallic manganese powder in a ball milling jar, evacuate the air, and ball mill it at a speed of 900 revolutions per minute for 12 hours; in an argon-filled glove box, mix the ball-milled metallic manganese powder with acetylene black and polyvinylidene fluoride in a mass ratio of 90:5:5, add N-methylpyrrolidone to make a slurry, coat the slurry on carbon cloth, and place it in an oven at 110 °C to dry completely for standby. The loading amount of metallic manganese powder in the negative electrode material is greater than 40 mg / cm 2 .

[0141] Performance test 4-1:

[0142] Assemble a TBA / Mn secondary battery. The assembly process is the same as that described in Performance Test 1-6, except that only the positive electrode plate and the electrolyte are replaced with a TBA electrode plate and the electrolyte in this example.

[0143] Perform a constant current charge-discharge (GCD) test on the TBA / Mn secondary battery at room temperature. The room temperature cycling performance and charge-discharge curves are as Figure 9 shown in Figures 9a and 9b. After stabilization at 0.1 A / g, the specific capacity is 45.2 mAh / g, showing good electrochemical activity; according to the charge-discharge curve, the average working voltage is ~1.3 V, indicating that the TBA / Mn secondary battery in this example has good electrochemical performance.

[0144] In this example, the carriers on the positive electrode side are Mn 2+ and AlCl2 + , and manganese metal deposition / stripping occurs at the negative electrode.

[0145] In this example, by adding additives to regulate the carriers, it has the potential for application in different electrode materials and different energy storage devices.

[0146] Example 5

[0147] Manganese cluster ion complex electrolyte:

[0148] It is obtained by completely dissolving 0.6 mmol of MnCl2, 0.6 mmol of AlCl3, and 0.6 mmol of Mn(TFSI)2 in 5 mL of a mixed solvent of diethylene glycol dimethyl ether and sulfolane with a volume ratio of 3:2.

[0149] The positive electrode material is polyaniline (PANI).

[0150] Negative electrode material:

[0151] Place the metallic manganese powder in a ball milling jar, evacuate the air, and ball mill it at a speed of 900 revolutions per minute for 12 hours; in an argon-filled glove box, mix the ball-milled metallic manganese powder with acetylene black and polyvinylidene fluoride in a mass ratio of 90:5:5, add N-methylpyrrolidone to make a slurry, coat the slurry on carbon cloth, and place it at 110 °C to dry completely for standby. The loading amount of the metallic manganese powder in the negative electrode material is greater than 40 mg / cm 2 .

[0152] Performance test 5-1:

[0153] In the manganese cluster ion complex electrolyte, the working electrode is a tungsten rod, the counter electrode is activated carbon and a tungsten rod, the reference electrode is a silver rod, and the scanning rate is 20 mV / s; the cyclic voltammetry (CV) test results under Swagelok three electrodes are as Figure 10 shown. The CV curve is a typical metal deposition / stripping type and has a low overpotential (less than 200 mV), indicating that the manganese cluster ion complex electrolyte of this embodiment can effectively deposit and strip manganese metal.

[0154] Performance test 5-2:

[0155] Assemble a PANI / Mn secondary battery. The assembly process is the same as that described in Performance Test 1-6, and only the positive electrode plate and the electrolyte need to be replaced with a PANI electrode plate and the electrolyte in this embodiment.

[0156] Perform a constant current charge-discharge (GCD) test on the PANI / Mn secondary battery at room temperature. The room temperature cycling performance and charge-discharge curves are as Figure 11 shown in Figures 11a and 11b. The specific capacity is 92 mAh / g after 100 cycles at 0.1 A / g, showing good cycling stability; according to the charge-discharge curve, the average working voltage is ~1.2 V, with good plateau characteristics. Perform a high current GCD test on the PANI / Mn secondary battery at room temperature. The results are as Figure 12 shown. The specific capacity does not show significant attenuation after more than 7500 cycles at 2 A / g, indicating that the PANI / Mn secondary battery has excellent cycling stability.

[0157] The carrier on the positive electrode side in this embodiment is AlCl 2+ , and manganese metal deposition / stripping occurs at the negative electrode.

[0158] Example 6

[0159] Manganese cluster ion complex electrolyte: Prepared by completely dissolving 1.1 mmol of MnCl2, 0.6 mmol of AlCl3, and 0.6 mmol of Mn(TFSI)2 in 20 mL of a mixture of tetrahydrofuran and sulfolane with a volume ratio of 3:2.

[0160] The positive electrode material is a conductive polymer poly(benzimidazole benzophenanthroline) (BBL) containing carbonyl and imino groups.

[0161] Negative electrode material:

[0162] Put the metallic manganese powder into a ball milling tank, evacuate it, and ball mill it at a speed of 900 revolutions per minute for 12 hours; in an argon-filled glove box, mix the ball-milled metallic manganese powder with acetylene black and polyvinylidene fluoride according to a mass ratio of 90:5:5, add N-methylpyrrolidone to make a slurry, coat the slurry on carbon cloth, and place it at 110 °C to dry completely for standby. The loading amount of metallic manganese powder in the negative electrode material is greater than 40 mg / cm 2 .

[0163] Performance test 6-1:

[0164] Assemble a button-type Mn / Mn symmetric battery. The assembly process is the same as that in Performance Test 1-3, only replacing the electrolyte with the electrolyte in this example.

[0165] The button-type Mn / Mn symmetric battery deposits / strips 0.1 mAh at a current of 0.1 mA. The room temperature cycle test results are shown in Figure 13a and it can operate stably for at least 500 hours; some charge-discharge curves are shown in Figure 13 Figure b, and its overpotential is always less than 20 mV; it shows that the manganese cluster ion complex electrolyte in this example has good room temperature stability.

[0166] Performance test 6-2:

[0167] Assemble a BBL / Mn secondary battery. The assembly process is the same as that in Performance Test 1-6, only replacing the electrolyte with the electrolyte in this example.

[0168] Conduct a room temperature constant current charge-discharge (GCD) test on the BBL / Mn secondary battery. The room temperature cycle performance and charge-discharge curves are shown in Figure 14 Figures a and 14b. The battery shows good cycle stability and rate performance at current densities of 0.01-0.02-0.05-0.08-0.1-0.2-0.3-0.5-1-2-3 A / g. Conduct an energy dispersive spectroscopy (EDS) test on the completely discharged BBL electrode sheet. The results are shown in Figure 14 Figure c. The elemental content shows that the atomic ratios of aluminum to manganese and aluminum to chlorine are 1.47 and 0.55 respectively.

[0169] The carriers on the positive electrode side in this example are AlCl2 + and Mn 2+ with a molar ratio of about 1.5:1, and manganese metal deposition / stripping occurs at the negative electrode.

[0170] In this embodiment, by changing the solute ratio and concentration, carriers are regulated, and it has the application potential in different electrode materials and different energy storage devices.

[0171] Example 7

[0172] Compared with Example 1, the difference is that the manganese cluster ion complex electrolyte is obtained by completely dissolving 0.6 mmol of MnBr2, 0.6 mmol of AlBr3, and 0.6 mmol of Mn(TFSI)2 in 5 mL of a mixture of tetrahydrofuran and sulfolane with a volume ratio of 3:2.

[0173] Performance test 7-1:

[0174] An assembled coin-type Mn-Mn symmetric battery, the assembly process is the same as that in Performance test 1-3, only replacing the electrolyte with the electrolyte in this embodiment.

[0175] The coin-type Mn-Mn symmetric battery deposits / strips 2 mAh at 5 mA and 10 mA currents. The room-temperature cycling test results are shown in 15a, and it can work normally; the charge-discharge curves at different currents are as Figure 15 shown in b. The average potential is less than 300 mV at 5 mA and less than 600 mV at 10 mA; it shows that the manganese cluster ion complex electrolyte in this embodiment has good high-current working performance.

[0176] Example 8

[0177] Manganese cluster ion complex electrolyte:

[0178] It is obtained by completely dissolving 0.6 mmol of MnCl2, 0.6 mmol of AlCl3, 0.6 mmol of Mn(OTf)2, and 1.8 mmol of tetraethylammonium trifluoromethanesulfonate in 5 mL of a mixture of tetrahydrofuran and sulfolane with a volume ratio of 3:2.

[0179] The positive electrode material is a Prussian blue analogue material (TBA).

[0180] Negative electrode material:

[0181] Put the metallic manganese powder into a ball milling tank, evacuate, and ball mill at a speed of 900 revolutions per minute for 12 hours; in an argon-filled glove box, mix the ball-milled metallic manganese powder with acetylene black and polyvinylidene fluoride according to a mass ratio of 90:5:5, add N-methylpyrrolidone to make a slurry, coat the slurry on carbon cloth, and place it at 110 °C to dry completely for standby. The loading amount of metallic manganese powder in the negative electrode material is greater than 40 mg / cm 2 .

[0182] Performance test 8-1:

[0183] Assemble the TBA / Mn secondary battery. The assembly process is the same as that described in Performance Tests 1-6, except that only the positive electrode sheet and the electrolyte are replaced with the TBA electrode sheet and the electrolyte in this example.

[0184] Perform constant current charge-discharge (GCD) tests on the TBA / Mn secondary battery at room temperature. Its typical charge-discharge curves are as Figure 16 shown. According to the charge-discharge curves, the average working voltage is ~1.1 V, indicating that the TBA / Mn secondary battery of this example also has good electrochemical performance.

[0185] Comparative Example 1

[0186] Non-manganese cluster ion complexing electrolyte:

[0187] Dissolve Mn(TFSI)2 completely in ethylene carbonate and dimethyl carbonate to obtain an electrolyte with a concentration of 0.5 mol / L.

[0188] Performance Test 1'-1: <s

[0189] In the non-manganese cluster ion complexing electrolyte, the working electrode is a stainless steel rod, the counter electrode is activated carbon and a tungsten rod, the reference electrode is a silver rod, and the scan rate is 1 mV / s; the cyclic voltammetry (CV) test results and the manganese deposition / stripping test diagrams under the three-electrode system are as Figure 17 shown in a and 17b. The CV curve is of the typical metal deposition / stripping type, but shows a high overpotential (greater than 700 mV), indicating that the use of the non-manganese cluster ion complexing electrolyte in this comparative example shows a high overpotential for manganese metal deposition / stripping and a low Coulombic efficiency.

[0190] Comparative Example 2

[0191] Non-manganese cluster ion complexing electrolyte:

[0192] Obtained by completely dissolving 1.2 mmol of MnBr2 and 0.6 mmol of Al(OTf)3 in 5 mL of a mixture of tetrahydrofuran and sulfolane with a volume ratio of 3:2.

[0193] Performance Test 2'-1:

[0194] Assemble a button-type asymmetric battery. The process is the same as that in Performance Tests 1-2 of Example 1, except that the electrolyte is replaced with the electrolyte of this comparative example. The button-type asymmetric battery deposits / strips 0.1 mAh at a current of 0.1 mA. The room temperature cycle test results are as shown in 18a and 18b. The overpotential is greater than 600 mV and the Coulombic efficiency is lower than 50%, indicating that the non-manganese cluster ion complexing electrolyte of this comparative example does not support low-overpotential and highly reversible manganese deposition / stripping.

[0195] Comparative Example 3

[0196] Compared with Example 1, the difference lies in that the manganese cluster ion complex electrolyte is obtained by completely dissolving 0.6 mmol of MnCl2, 0.6 mmol of AlCl3, and 0.6 mmol of Mn(TFSI)2 in 5 mL of tetrahydrofuran.

[0197] Performance Test 3'-1:

[0198] The BBL / Mn secondary battery in Performance Tests 1-6 of Example 1 was used for testing, and only the electrolyte was replaced with the electrolyte of this comparative example.

[0199] The assembled BBL / Mn secondary battery was subjected to constant current charge and discharge (GCD) tests at room temperature. The room temperature cycle performance and charge and discharge curves are as Figure 19 shown in a and 19b. Although the Coulomb efficiency of this secondary battery always remained at about 100%, the specific capacity decayed rapidly. As Figure 19 shown in c, the electrolyte gradually solidified after long-term storage, which may be the reason for battery failure.

[0200] In summary, the manganese cluster ion complex electrolyte of the present invention can deposit and strip manganese metal at -40 to 60 °C; and the electrochemical energy storage device containing the manganese cluster ion complex electrolyte has excellent electrochemical performance and can work normally at temperatures from -30 to 60 °C, having good application prospects.

[0201] All aspects, embodiments, and features of the present invention should be considered illustrative in all respects and not limiting the present invention. The scope of the present invention is only defined by the claims. Without departing from the spirit and scope of the claimed invention, those skilled in the art will appreciate other embodiments, modifications, and uses.

[0202] In the preparation method of the present invention, the order of each step is not limited to the listed order. For those of ordinary skill in the art, without creative efforts, the changes in the order of each step are also within the protection scope of the present invention. In addition, two or more steps or actions can be carried out simultaneously.

[0203] Finally, it should be noted that the specific embodiments described herein are only illustrative of the present invention and do not limit the implementation manner of the present invention. Those skilled in the art of the present invention can make various modifications or supplements to the described specific embodiments or use similar methods for substitution. It is not necessary and impossible to list all the implementation manners here. And these obvious changes or variations derived from the essence of the present invention still fall within the protection scope of the present invention. Interpreting them as any additional restrictions is contrary to the spirit of the present invention.

Claims

1. A manganese cluster ion complex electrolyte, characterized in that, It is prepared by dissolving manganese halide, Lewis acid, and manganese salt of non-halide manganese with a molar ratio of 1:(0.1-5):(0.1-5) in a non-aqueous solvent; in the manganese cluster ion complex electrolyte, manganese ions form binuclear manganese cluster ions through bridge bonds constructed by halogen ions.

2. The manganese cluster ion complex electrolyte according to claim 1, wherein The manganese halide is one or more of manganese fluoride, manganese chloride, manganese bromide, and manganese iodide.

3. The manganese cluster ion complex electrolyte according to claim 1, characterized in that, The Lewis acid includes, but is not limited to, one or more of aluminum fluoride, aluminum chloride, aluminum bromide, aluminum iodide, boron fluoride, boron chloride, boron bromide, boron iodide, gallium fluoride, gallium chloride, gallium bromide, gallium iodide, indium fluoride, indium chloride, indium bromide, indium iodide, antimony fluoride, antimony chloride, antimony bromide, antimony iodide, aluminum bis(trifluoromethanesulfonyl)imide, aluminum bis(fluorosulfonyl)imide, and aluminum trifluoromethanesulfonate.

4. The manganese cluster ion complex electrolyte according to claim 1, wherein The manganese salt of non-halide manganese includes, but is not limited to, one or more of manganese bis(trifluoromethanesulfonyl)imide, manganese bis(fluorosulfonyl)imide, manganese trifluoromethanesulfonate, manganese perchlorate, manganese nitrate, and manganese acetate.

5. The manganese cluster ion complex electrolyte according to claim 1, characterized in that The manganese cluster ion complex electrolyte further contains an additive; the additive includes, but is not limited to, one or more of bis(trifluoromethanesulfonyl)imide salts, bis(fluorosulfonyl)imide salts, trifluoromethanesulfonate salts, perchlorate salts, nitrate salts, acetate salts, etc. of symmetric or asymmetric quaternary ammonium cations such as tetramethylammonium, tetraethylammonium, and tetrapropylammonium.

6. The manganese cluster ion complex electrolyte according to claim 1, characterized in that The manganese cluster ion complex electrolyte remains liquid at -40 to 60 °C; and reversible deposition and stripping of metallic manganese are achieved within the range of -40 to 60 °C.

7. An electrochemical energy storage device for manganese metal, characterized in that, It includes the manganese cluster ion complex electrolyte according to any one of claims 1 to 6.

8. The manganese metal electrochemical energy storage device according to claim 7, wherein The manganese metal electrochemical energy storage device operates stably at a temperature of -40 to 60 °C.

9. A manganese metal capacitor, characterized in that, It includes the manganese cluster ion complex electrolyte according to any one of claims 1 to 6. The manganese metal capacitor deposits / strips 0.1 to 2 mAh at a current of 1 to 10 mA, with an average potential < 600 mV at room temperature and an average potential < 700 mV at -40 °C.

10. A secondary manganese metal battery, characterized in that, It includes the manganese cluster ion complex electrolyte according to any one of claims 1 to 6; the manganese metal secondary battery operates stably at a temperature of -30 to 60 °C.

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