Battery electrolyte solvent capable of adapting to wide temperature range and preparation of battery

Abstract

The invention belongs to the technical field of batteries, discloses a battery electrolyte solvent capable of adapting to a wide temperature range and preparation of a battery, and provides application of a mixed organic solvent as an energy storage battery electrolyte solvent, the mixed organic solvent is composed of tetrahydrofuran, 1, 3-dioxolame and 1, 1, 2, 2-tetrafluoroethyl-2, 2, 2-trifluoroethyl ether, and the 1, 1, 2, 2-tetrafluoroethyl-2, 2, 2-trifluoroethyl ether is composed of tetrahydrofuran, 1, 3-dioxolame and 1, 1, 2, 2-tetrafluoroethyl-2, 2, 2-trifluoroethyl ether. The volume percent content of the 1, 2, 2-trifluoroethyl ether is 10%-50%. The solvent composition of the energy storage battery electrolyte is improved, 1, 1, 2, 2-tetrafluoroethyl-2, 2, 2-trifluoroethyl ether is introduced into an ether organic solvent (namely tetrahydrofuran and 1, 3-dioxolame) to serve as a diluent, meanwhile, the volume percentage of the diluent is controlled, and the obtained electrolyte solvent formula can adapt to the wide temperature range of the full temperature interval of-130 DEG C to 60 DEG C, so that the energy storage battery electrolyte is suitable for being used as an energy storage battery electrolyte. And the problem of battery failure of the current energy storage battery under the extremely low-temperature and high-temperature conditions can be effectively solved.

Description

Technical Field

[0001] This invention belongs to the field of battery technology, and more specifically, relates to a battery electrolyte solvent that can adapt to a wide temperature range and the preparation of the battery. Background Technology

[0002] Energy storage batteries are widely used in various electronic devices, including military and security equipment, electric vehicles, home appliances, and wearable devices, due to their high energy density, low cost, and portability. However, traditional lithium-ion batteries can only achieve normal capacity and long cycle life at room temperature, and problems arise at both high and low temperatures (for example, at temperatures below -40°C, the capacity can only maintain 12% of its room temperature performance). However, the lowest temperatures in many regions of the Earth are far higher than -40°C. As early as 1983, the lowest temperature ever recorded on Earth was -89.6°C at Vostok Station in Antarctica; in 2013, the highest point in the East Antarctic Plateau recorded a record low of -93°C, and in 2019, this figure was updated to -100°C; until 2021, when the National Oceanic and Atmospheric Administration's weather satellites monitored a tropical storm in the western Pacific Ocean and recorded a minimum temperature of -111.2°C, which is considered the lowest temperature ever recorded on Earth. Furthermore, at temperatures above room temperature, electrolytes are susceptible to volatilization and thermal decomposition. This is because the energy provided by the increased temperature to the battery system exacerbates internal side reactions, increasing battery wear and reducing its lifespan. The highest temperature ever recorded on Earth is 56.7°C. Therefore, there is an urgent need to research batteries capable of stable operation over a wide temperature range, which is of great significance for public welfare, scientific research, and national defense.

[0003] The failure mechanisms of traditional lithium-ion batteries at low temperatures mainly include the following aspects: As the temperature decreases, the solubility of lithium salts decreases and then precipitates, the viscosity of the electrolyte increases or even solidifies, ion transport is hindered, and charge exchange between electrodes slows down, which in turn leads to a decrease in the capacity release of the battery at a certain current density; lithium-ion desolvation is difficult because the desolvation barrier at low temperatures is relatively higher than at room temperature, and lithium ions need to remove solvent molecules in order to enter the electrode material to achieve charge transport and energy storage. Current opinion holds that the desolvation process is a key factor limiting the use of batteries in low-temperature environments; the electrode / electrolyte solid interface layer formed at low temperatures is thicker, more uneven, and has a more complex composition, resulting in greater charge transfer resistance and a poorer lithium-ion conduction effect.

[0004] At high temperatures, battery failure can be caused by a variety of factors: the dissolution of electrode materials in the electrolyte is exacerbated, leading to the loss of active materials; irreversible reactions such as electrolyte evaporation or even thermal decomposition interrupt the lithium-ion transport channels between electrodes, severely damaging the battery's cycle life; and the continuous decomposition and reconstruction of the electrode / electrolyte solid interface layer consumes lithium sources and electrolyte components and generates a large number of byproducts, which is detrimental to battery cycling.

[0005] Traditional commercial lithium-ion batteries use ester-based reagents, which have properties such as high viscosity, high melting point, and strong coordination ability. They can exhibit stable performance at room temperature, but their conductivity drops sharply at -20°C and the electrolyte undergoes continuous irreversible decomposition at temperatures above 50°C, which severely limits their use in a wide temperature range.

[0006] Ethers are considered excellent solvents for designing low-temperature electrolytes due to their low melting point, low viscosity, and good compatibility with lithium metal / silicon anodes. Current research on low-temperature batteries based on ethers is frequently reported, but most studies are conducted in environments of -40°C and above, with a few reaching -70°C, which does not fully utilize the low melting point of ether solvents. Furthermore, these studies rarely consider the battery's performance in environments above room temperature, while in real-world conditions, battery operation is often complex and variable.

[0007] If an electrolyte solvent formulation that can adapt to batteries with a wider temperature range can be provided, it will undoubtedly promote the wider application of energy storage batteries. Summary of the Invention

[0008] To address the aforementioned deficiencies or improvement needs of existing technologies, the present invention aims to provide a battery electrolyte solvent and battery preparation method that can adapt to a wide temperature range. This is achieved by improving the solvent composition of the energy storage battery electrolyte by introducing 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether as a diluent into an ether-based organic solvent (i.e., tetrahydrofuran, 1,3-dioxolane). Simultaneously, by controlling the volume percentage of the diluent in the overall mixed organic solvent to 10%~50%, the resulting electrolyte solvent formulation can adapt to a wide temperature range of -130~60°C, while also considering both low and high temperatures. This effectively solves the problem of battery failure encountered by current energy storage batteries under extreme low and high temperature conditions.

[0009] To achieve the above objectives, according to one aspect of the present invention, a mixed organic solvent is provided as an application of a solvent for an energy storage battery electrolyte, characterized in that the mixed organic solvent is composed of tetrahydrofuran, 1,3-dioxolane, and 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether, wherein the volume percentage content of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether in the mixed organic solvent is 10% to 50%.

[0010] As a further preferred embodiment of the present invention, the electrolyte is capable of operating in a wide temperature range of -130 to 60°C; Preferably, the electrolyte is capable of operating at a temperature of -130 to -40°C; more preferably, the electrolyte is capable of operating at a temperature of -130 to -80°C.

[0011] As a further preferred embodiment of the present invention, the volume ratio of tetrahydrofuran to 1,3-dioxolane in the mixed organic solvent is (1~5):(1~5).

[0012] As a further preferred embodiment of the present invention, the electrolyte is obtained by dissolving lithium salt in the mixed organic solvent.

[0013] As a further preferred embodiment of the present invention, the lithium salt is one or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium difluorophosphate, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium bis(oxalateborate), lithium difluorooxalateborate, lithium trifluoromethanesulfonate, lithium hexafluoroarsenate, lithium perchlorate, lithium nitrate, lithium fluoride, lithium chloride, lithium bromide, lithium carbonate, and lithium sulfate.

[0014] As a further preferred embodiment of the present invention, the concentration of lithium salt in the electrolyte is 0.5~3 M.

[0015] According to another aspect of the present invention, an electrolyte is provided, characterized in that it is a mixed organic solvent composed of tetrahydrofuran, 1,3-dioxolane and 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether; wherein the volume percentage content of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether in the mixed organic solvent is 10% to 50%.

[0016] According to another aspect of the present invention, a lithium battery is provided, characterized in that its electrolyte is a mixed organic solvent composed of tetrahydrofuran, 1,3-dioxolane, and 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether; wherein the volume percentage content of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether in the mixed organic solvent is 10% to 50%.

[0017] As a further preferred embodiment of the present invention, the lithium battery is a lithium metal battery or a lithium-ion battery; Preferably, when the lithium battery is a lithium metal battery, the positive electrode active material used is one or more of lithium cobalt oxide, lithium iron phosphate, binary and ternary electrode materials based on nickel cobalt manganese, organic electrode materials, hard carbon, carbon black, lithium titanate, silicon, bismuth, and tin, and the negative electrode is lithium metal. When the lithium battery is a lithium-ion battery, the positive electrode active material used is one of lithium cobalt oxide, lithium iron phosphate, binary and ternary electrode materials based on nickel cobalt manganese, and organic electrode materials, and the negative electrode active material is one of organic electrode materials, hard carbon, carbon black, lithium titanate, silicon, bismuth, and tin. More preferably, in the lithium metal battery, the areal loading of the positive electrode active material of the positive electrode sheet is 0.2~200 mg / cm². 2 ; In the lithium-ion battery, the areal loading of the positive electrode active material in the positive electrode sheet is 0.2~200 mg / cm². 2 The areal loading of the negative electrode active material in the negative electrode sheet is 0.2~200 mg / cm². 2 ; The organic electrode material is selected from quinone organic electrode materials, organosulfur electrode materials, phenazine organic electrode materials, aniline organic electrode materials, nitrogen-containing fused ring organic electrode materials, carboxylic acid derivative organic electrode materials, conjugated aromatic ketone organic electrode materials, free radical polymer electrode materials, conjugated polymer organic electrode materials, and metal-organic framework electrode materials.

[0018] According to another aspect of the present invention, the present invention provides the application of the above-mentioned lithium battery in a wide temperature range of -130 to 60°C; Preferably, the application is performed at a temperature of -130 to -40°C; more preferably, the application is performed at a temperature of -130 to -80°C.

[0019] Compared with the prior art, the present invention introduces 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether as a diluent into ether-based organic solvents (i.e., tetrahydrofuran, 1,3-dioxolane), while controlling the volume percentage of the diluent in the overall mixed organic solvent to be 10%~50%. The resulting electrolyte solvent formulation can adapt to a wide temperature range of -130~60°C, while also taking into account both low and high temperatures.

[0020] This invention uses tetrahydrofuran, which has a low melting point, low viscosity, and high dielectric constant, because it can remain liquid at extremely low temperatures and provide high ionic conductivity. It also uses 1,3-dioxolane, which has a low melting point and readily forms organic polymers through ring-opening, as a film-forming agent. This allows for the formation of a dense interfacial layer, which helps protect against interfacial mismatch between the electrode and electrolyte caused by temperature changes and reduces side reactions (1,3-dioxolane can undergo in-situ ring-opening polymerization under the catalysis of current to form a dense interfacial layer, which can be used to protect the electrode material from interfacial damage caused by volume changes due to temperature variations). Unlike existing technologies that use tetrahydrofuran and 1,3-dioxolane, this invention adds 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether as a diluent to prevent excessive intermolecular forces at low temperatures from hindering ion transport. Furthermore, by controlling the volume percentage of the diluent in the overall mixed organic solvent to 10%~50%, this proportion allows 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether to not only balance the intermolecular forces at low temperatures and reduce the obstruction to ion transport, effectively ensuring the electrode's capacity, but also to minimize the impact of the diluent on conductivity reduction, thus minimizing the impact on battery performance.

[0021] This invention utilizes the synergistic effect of three solvents—tetrahydrofuran, 1,3-dioxolane, and 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether—to broaden the low-temperature limit of the electrolyte. Thanks to the weak binding interactions between tetrahydrofuran and 1,3-dioxolane with lithium ions, they not only provide some electrostatic interaction for lithium salt dissolution but are also insufficient to completely isolate lithium ions from anions. During solvation, lithium ions tend to bind with anions, and the inner solvation structure is almost entirely composed of anions. Tetrahydrofuran and 1,3-dioxolane have fewer coordination sites in the inner layer. 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether, as a diluent, has many sites replaced by highly electronegative fluorine, reducing the lone pair electron density on the oxygen atom. It exists almost exclusively in the outer solvation structure of lithium ions and does not participate in inner-layer coordination. This anion-rich solvation structure exhibits a lower desolvation barrier compared to solvent-rich solvation structures during the desolvation process. At the same time, this solvation structure is more conducive to the decomposition of anions, constructing a dense and good interface layer to achieve rapid ion transport in the electrolyte. Ultimately, this allows the electrolyte to maintain a relatively high charge transport efficiency over a wide temperature range, and the battery to maintain stable cycling over a wide temperature range.

[0022] Based on the solvent formulation of the mixed organic solvent in this invention, taking the dissolution of lithium salt as an example, the resulting electrolyte exhibits the characteristic of tolerating a wide temperature range. In the examples below, the electrolyte has an ultra-low temperature freezing point of -139°C, while also exhibiting low viscosity and high ionic conductivity, which is beneficial for forming a solvation structure rich in anions and a relatively dense interface layer. The electrolyte and the battery constructed using the corresponding electrolyte can tolerate a wide temperature range of -130 to 60°C. The battery can achieve charge and discharge at -130 to 60°C, balancing low and high temperatures. Furthermore, the specific capacity of the battery at 60°C and 25°C are 351 mAh / g and 352 mAh / g, respectively, close to the theoretical capacity (357 mAh / g). The capacity release at -40°C is 86% of the theoretical capacity, and the capacity retention rate at -70°C is 49%. The battery exhibits excellent wide-range temperature tolerance performance. Furthermore, the battery exhibited stable long-cycle performance at 60°C, 25°C, -40°C, and -70°C, and also had a high capacity retention rate.

[0023] Furthermore, as illustrated in the embodiments below, the electrolyte formed using the solvent formulation of the mixed organic solvent in this invention is universal, can be matched with a variety of electrode materials, and achieves excellent performance. Attached Figure Description

[0024] Figure 1 It is a differential scanning calorimeter of the electrolyte in Example 1 that can adapt to a wide temperature range.

[0025] Figure 2 This is the ionic conductivity test of the wide-temperature-range electrolyte in Example 1 at different temperatures.

[0026] Figure 3 These are the charge-discharge curves at 25°C of lithium metal batteries prepared with electrolytes containing different diluent contents in Examples 1, 1-1, 1-2, 1-3, and 1-4.

[0027] Figure 4 These are the charge-discharge curves at -40°C for lithium metal batteries prepared with electrolytes containing different diluent contents in Examples 1, 1-1, 1-2, 1-3, and 1-4.

[0028] Figure 5 The charge-discharge curves at 25°C are for lithium metal batteries prepared with electrolytes containing different relative contents of tetrahydrofuran and 1,3-dioxolane in Examples 1, 1-5, 1-6, 1-7, and 1-8.

[0029] Figure 6The charge-discharge curves at -40°C are for lithium metal batteries prepared with electrolytes containing different relative contents of tetrahydrofuran and 1,3-dioxolane in Examples 1, 1-5, 1-6, 1-7, and 1-8.

[0030] Figure 7 These are the charge-discharge curves at 25°C of lithium metal batteries prepared with electrolytes of different lithium salt concentrations in Examples 1, 1-9, 1-10, 1-11, and 1-12.

[0031] Figure 8 These are the charge-discharge curves of lithium metal batteries prepared with electrolytes of different lithium salt concentrations in Examples 1, 1-9, 1-10, 1-11, and 1-12 at -40°C.

[0032] Figure 9 These are the charge-discharge curves of the wide-temperature-range lithium metal battery in Example 2 at -85~60°C.

[0033] Figure 10 These are the charge-discharge curves of the wide-temperature-range lithium metal battery in Example 2 at -120 to -100°C.

[0034] Figure 11 This is a photograph of the LED light with the word "HUST" printed on it, lit by the wide-temperature-range lithium metal battery at -129.6°C in Example 2; from left to right, the LED is not connected to the battery in a bright environment, the LED is not connected to the battery in a dark environment, and the LED is connected to the battery in a dark environment.

[0035] Figure 12 These are the charge-discharge curves of lithium metal batteries at 25°C for different electrode material loadings in Examples 2 and 2-1, 2-2, 2-3, 2-4, 2-5, and 2-6.

[0036] Figure 13 This refers to the long-cycle test of the wide-temperature-range lithium metal battery in Example 2 at 60°C, 25°C, -40°C, and -70°C.

[0037] Figure 14 This is the long-cycle test of the wide-temperature-range lithium-ion battery in Example 3 at 25°C and -70°C. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0039] Example 1 Preparation of an electrolyte adaptable to a wide temperature range. The entire preparation process was carried out in an inert atmosphere glove box with water <0.1ppm and oxygen <0.1ppm (Ar gas was used in this embodiment as the inert atmosphere). A glass bottle was filled with a magnetic brick, and lithium bis(trifluoromethanesulfonyl)imide was weighed out according to a salt concentration of 1 M and added to the bottle. Then, 1,3-dioxolane, tetrahydrofuran, and 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether were added in a volume fraction ratio of 1:2:1. The bottle was placed on a stirring table and stirred for 1 hour to obtain a clear and transparent solution.

[0040] Example 1-1: Refer to Example 1, except that the volume fraction ratio of 1,3-dioxolane, tetrahydrofuran, and 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether is 4.5:4.5:1, and the corresponding volume fraction of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether is 10%.

[0041] Examples 1-2: Refer to Example 1, except that the volume fraction ratio of 1,3-dioxolane, tetrahydrofuran, and 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether is 1:1:1, and the corresponding volume fraction of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether is 33%.

[0042] Examples 1-3: Refer to Example 1, except that the volume fraction ratio of 1,3-dioxolane, tetrahydrofuran, and 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether is 1:2:2, and the corresponding volume fraction of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether is 40%.

[0043] Examples 1-4: Refer to Example 1, except that the volume fraction ratio of 1,3-dioxolane, tetrahydrofuran, and 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether is 1:1:2, and the corresponding volume fraction of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether is 50%.

[0044] Examples 1-5: Refer to Example 1, except that in the mixed system of 1,3-dioxolane, tetrahydrofuran, and 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether, the volume percentage of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether is controlled at 25%, and the volume ratio of 1,3-dioxolane to tetrahydrofuran is 5:1.

[0045] Examples 1-6: Refer to Example 1, except that in the mixed system of 1,3-dioxolane, tetrahydrofuran, and 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether, the volume percentage of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether is controlled at 25%, and the volume ratio of 1,3-dioxolane and tetrahydrofuran is 2:1.

[0046] Examples 1-7: Refer to Example 1, except that in the mixed system of 1,3-dioxolane, tetrahydrofuran, and 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether, the volume percentage of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether is controlled at 25%, and the volume ratio of 1,3-dioxolane and tetrahydrofuran is 1:1.

[0047] Examples 1-8: Refer to Example 1, except that in the mixed system of 1,3-dioxolane, tetrahydrofuran, and 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether, the volume percentage of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether is controlled at 25%, and the volume ratio of 1,3-dioxolane and tetrahydrofuran is 1:5.

[0048] Examples 1-9: Refer to Example 1, except that the concentration of lithium bis(trifluoromethanesulfonylimide) is 0.5M.

[0049] Examples 1-10: Refer to Example 1, except that the concentration of lithium bis(trifluoromethanesulfonylimide) is 1.5M.

[0050] Examples 1-11: Refer to Example 1, except that the concentration of lithium bis(trifluoromethanesulfonylimide) is 2M.

[0051] Examples 1-12: Refer to Example 1, except that the concentration of lithium bis(trifluoromethanesulfonylimide) is 3M.

[0052] Figure 1 The differential scanning calorimetry (DSC) of the electrolyte described in Example 1, which can adapt to a wide temperature range, shows that the electrolyte always maintains a stable liquid state in a temperature environment of -130°C or higher, without any changes in the physical state of the substance such as solvent solidification and salt precipitation.

[0053] Figure 2 This refers to the ionic conductivity test of the wide-temperature-range electrolyte described in Example 1 at different temperatures. The ionic conductivity of the electrolyte is greater than 4 mS / cm at -40°C and greater than 1 mS / cm at -70°C, indicating that the electrolyte maintains sufficient ionic conductivity while remaining stable at low temperatures.

[0054] Using the lithium salt solution obtained in Example 1 above as the electrolyte, a lithium metal battery was constructed. This lithium metal battery adopts a button cell structure, and the electrode fabrication and button cell assembly are performed according to the following steps: Preparation of the positive electrode sheet: 2,3,7,8-tetraaminophenazine-1,4,6,9-tetraone (active material), carbon black (conductive additive), and polyvinylidene fluoride (binder) were weighed in a mass ratio of 6:3:1, ground evenly in a mortar, and N-methylpyrrolidone was added as a dispersant for further grinding to form a uniform slurry. This slurry was then coated onto aluminum foil, dried in an oven at 80°C for 12 hours, and cut into round sheets with a diameter of 12 mm. The loading of the active material was 1 mg / cm³. 2 .

[0055] The button cell is assembled in the following order: positive electrode shell, positive electrode plate, separator, negative electrode, gasket, spring, and negative electrode shell. The negative electrode is lithium metal, the electrolyte volume is 80uL, and the separator consists of one layer of Celgard 2500 and one layer of glass fiber separator.

[0056] To discuss the universality of the electrolyte of this invention, in addition to using 2,3,7,8-tetraaminophenazine-1,4,6,9-tetraone (TAPT), we also tried using lithium cobalt oxide (LCO), lithium iron phosphate (LFP), 2,3-diaminonaphthalene-1,4-diketone-pyrene-4,5,9,10-tetraone (DNQ-PTO), poly(hexaazatriphenyl sulfonate) (PHATNS), carbon black (Super P), hard carbon (HC), bismuth (Bi), lithium titanate (LTO), lithium 4,4′-dicarboxystyrene anhydride (LSDC), and lithium phthalate (LBDC). These different positive electrode active materials replaced TAPT to prepare positive electrode sheets, and carbon black was still used as a conductive additive. The specific types of binders and the mass ratio of active material to conductive agent to binder are detailed in Table 1. The test results of the correspondingly prepared lithium metal button batteries (still using lithium metal as the negative electrode, and the lithium salt solution obtained in Example 1 as the electrolyte) at 25°C and a current density of 0.2 A / g are shown in Table 1. It can be seen that the electrolyte obtained based on this invention has universality and can be adapted to different electrode materials.

[0057] Table 1: Test results of lithium metal batteries at 25°C and a current density of 0.2 A / g

[0058] Based on the aforementioned “TAPT / / Li” lithium metal battery, we also experimented with lithium salt solutions obtained from different embodiments as electrolytes. Figure 3 and Figure 4 The charge-discharge capacity curves of lithium metal batteries prepared with the electrolytes from Examples 1, 1-1, 1-2, 1-3, and 1-4 at 25°C and -40°C are presented. The use of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether as a diluent can reduce the possibility of tetrahydrofuran and 1,3-dioxolane clustering; however, the highly fluorinated diluent also brings problems such as reduced conductivity. Therefore, the amount of diluent used needs to be carefully considered and a compromise made. From... Figure 3 As can be seen, the lithium metal battery corresponding to Example 1 can release a specific capacity of 345 mAh / g, which is about 97% of the theoretical capacity (357 mAh / g). The capacity retention rates of the batteries in Examples 1-1, 1-2, 1-3, and 1-4 are 89%, 94%, 96%, and 94%, respectively.

[0059] exist Figure 4 As can be seen, at -40℃, the capacity release of Examples 1, 1-1, 1-2, 1-3, and 1-4 were 293 mAh / g, 213 mAh / g, 279 mAh / g, 258 mAh / g, and 214 mAh / g, respectively. This indicates that when the diluent concentration is within the range of 10% to 50%, the lithium metal battery still exhibits good low-temperature performance (compared to room temperature capacity, the retention rate is all >60%), with the optimal effect observed when the diluent concentration is within the range of 25% to 40%. This is because a suitable concentration of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether not only lowers the melting point of the overall system but also reduces intermolecular interactions, accelerates ion transport at low temperatures, and keeps the decrease in conductivity caused by the diluent within an acceptable range.

[0060] Figure 5 and Figure 6The charge-discharge curves of lithium metal batteries prepared using Examples 1, 1-5, 1-6, 1-7, and 1-8 as electrolytes are presented at room temperature (25°C) and low temperature (-40°C). The influence of the relative content of tetrahydrofuran and 1,3-dioxolane in the electrolyte on performance is discussed. It can be seen that for Examples 1, 1-5, 1-6, 1-7, and 1-8, the capacity release at low temperature relative to room temperature is close to 85%, 74%, 77%, 78%, and 70%, respectively, all achieving good results (with Example 1 showing the best performance). This may be mainly due to the competition for coordination between tetrahydrofuran and 1,3-dioxolane and lithium ions at low temperatures. From the perspective of solvent molecular structure, tetrahydrofuran, with its monooxygen structure, has greater molecular polarity and exhibits a stronger coordination ability with lithium ions, resulting in higher ionic conductivity at room temperature (as shown in Table 2). However, as the temperature decreases, the slowdown in kinetics makes it more difficult for lithium ions to desolvate. Therefore, when designing wide-temperature-range electrolytes, it is necessary to consider not only the ionic conductivity at room temperature, but also the ionic conductivity at low temperatures.

[0061] Table 2: Electrolyte conductivity at different relative contents of tetrahydrofuran and 1,3-dioxolane

[0062] Figure 7 and Figure 8 The charge-discharge capacity curves of lithium metal batteries prepared using the electrolyte in Examples 1, 1-9, 1-10, 1-11, and 1-12 are presented at room temperature (25°C) and low temperature (-40°C). Figure 7 It can be observed that the difference in concentration at room temperature will result in a slight difference in battery capacity, but this effect will be amplified at low temperatures. This is because the increase in salt concentration will lead to an increase in viscosity, and more lithium ions will participate in the coordination with the solvent, increasing the barrier to desolvation.

[0063] Example 2 Fabrication of a lithium metal battery adaptable to a wide temperature range. The cathode is 2,3,7,8-tetraaminophenazine-1,4,6,9-tetraone, with a loading of 1 mg / cm³. 2The negative electrode is lithium metal, and the electrolyte is the electrolyte described in Example 1. 2,3,7,8-Tetraaminophenazine-1,4,6,9-tetraone (active material), carbon black (conductive additive), and polytetrafluoroethylene (binder) were weighed in a mass ratio of 6:3:1, ground uniformly in a mortar, and anhydrous ethanol was added as a dispersant for further grinding to form a uniform film. The film was dried in an oven at 80°C for 12 hours, cut into 12 mm diameter discs, and pressed onto stainless steel to obtain the positive electrode sheet. The positive electrode sheet was assembled in the following order: positive electrode shell, positive electrode sheet, separator, negative electrode, gasket, spring, and negative electrode shell. The electrolyte volume was 80 μL, and the separator consisted of one layer of Celgard 2500 and one layer of glass fiber separator.

[0064] Example 2-1: Referring to Example 2, the mass ratio of active material, conductive additive, and binder is 9:0.5:0.5.

[0065] Example 2-2: Refer to Example 2-1, except that the loading of the active material is 5 mg / cm³. 2 .

[0066] Examples 2-3: Refer to Example 2-1, except that the loading of the active material is 20 mg / cm³. 2 .

[0067] Examples 2-4: Refer to Example 2-1, except that the loading of the active material is 30 mg / cm³. 2 .

[0068] Examples 2-5: Refer to Example 2-1, except that the loading of the active material is 40 mg / cm³. 2 .

[0069] Examples 2-6: Refer to Example 2-1, except that the loading of the active material is 50 mg / cm³. 2 .

[0070] Figure 9 and Figure 10The charge-discharge curves of the lithium metal battery in Example 2 are presented in the range of -120 to 60°C. At different temperatures of 60°C, 25°C, -40°C, -55°C, -60°C, -65°C, -70°C, -80°C, -85°C, -100°C, -110°C, and -120°C, the discharge capacities are 351 mAh / g, 352 mAh / g, 307 mAh / g, 203 mAh / g, 181 mAh / g, 170 mAh / g, 165 mAh / g, 127 mAh / g, 114 mAh / g, 82 mAh / g, 35 mAh / g, and 24 mAh / g, respectively. This indicates that the battery can achieve normal charge-discharge within a wide temperature range of -120 to 60°C. Meanwhile, Figure 11 The lithium metal battery in Example 2 can also power LED bulbs with the letter "HUST" connected at a temperature of ~-130°C (the relevant parameters of the LED bulbs are shown in Table 3; these 25 LED bulbs are connected in parallel across the lithium metal battery obtained in Example 2, wherein the 7 LEDs for "H", the 6 LEDs for "U", the 7 LEDs for "S", and the 5 LEDs for "T" are all connected in parallel; "H", "U", "S", and "T" are connected in parallel with each other). Figure 11 (As shown, the red wire is connected to the positive terminal and the black wire is connected to the negative terminal). The LED bulb was successfully lit, indicating that the lithium metal battery in Example 2 can withstand a temperature range of -130°C to 60°C.

[0071] Table 3: Relevant parameters of the LED lights on the "HUST" circuit board

[0072] Figure 12 Battery test data at 25°C for Examples 2 and 2-1, 2-2, 2-3, 2-4, 2-5, and 2-6 are provided. It can be seen that even at 50 mg / cm³... 2 Under high load conditions, the battery can still release a specific capacity of 222 mAh / g, achieving a retention rate of 62% relative to the theoretical capacity. It is evident that the wide-temperature-range electrolyte obtained by this invention, which can adapt to a wide temperature range, is expected to realize a battery with high energy density.

[0073] Figure 13Long-cycle test data of the lithium metal battery in Example 2 at 60°C, 25°C, -40°C, and -70°C are provided. It can be seen that after 50 cycles at all temperatures, the battery still maintains a high capacity release level, with capacity retention rates of 82%, 88%, 98%, and 93% at each temperature. This indicates that the lithium metal battery adapted to a wide temperature range obtained based on this invention has good temperature tolerance and cycle stability.

[0074] In addition, the lithium metal battery obtained in Example 2 has a leading wide temperature range tolerance in the field, exhibiting a temperature range of nearly 190°C, as shown in Table 4.

[0075] Table 4: Performance Comparison Table between Example 2 and Existing Reports

[0076] Note: References [1]-

[21] are as follows: [1]Zhao R , Gao Y , Qin Z ,et al.Regulating electric double layer innon-fluorinated ether electrolyte enables high-voltage and low-temperaturelithium metal batteries[J].Advanced Powder Materials, 2025, 4(3).DOI:10.1016 / j.apmate.2025.100296. [2]Zhang [3]Liang, P., Hu, H., Dong, Y., Wang, Z., Liu, K., Ding, G.,&Cheng,F. (2024). Competitive Coordination of Ternary Anions Enabling Fast Li‐IonDesolvation for Low‐Temperature Lithium Metal Batteries. Advanced FunctionalMaterials, 34(16). https: / / doi.org / 10.1002 / adfm.202309858 [4]Liu K , Zhang W , Feng Q ,et al.Multifunctional electrolyteadditive for high power lithium metal batteries at ultra-low temperatures[J].2024.DOI:10.21203 / rs.3.rs-5474223 / v1. [5]Jin C B , Yao N , Xiao Y ,et al.Taming Solvent–Solute InteractionAccelerates Interfacial Kinetics in Low‐Temperature Lithium‐Metal Batteries[J].Advanced Materials, 2022, 35.DOI:10.1002 / adma.202208340. [6]Lai P , Deng X , Zhang Y .Bifunctional Localized High-Concentration Electrolyte for the Fast Kinetics of Lithium Batteries at LowTemperatures[J].ACS applied materials&interfaces, 2023.DOI:10.1021 / acsami.3c04747. [7]Li C , Zhang J , Sun J ,et al.Electronic effect tuned ion-dipoleinteractions for low-temperature electrolyte design of LiFePO4-based lithium-ion batteries[J].Journal of Energy Storage, 2024(Nov. Pt.B):102.DOI:10.1016 / j.est.2024.114207. [8]Li X , Li M , Liu Y ,et al.Fast Interfacial DefluorinationKinetics Enables Stable Cycling of Low-Temperature Lithium Metal Batteries[J].[2025-12-11]. [9]Wang K H , Ma P , Kim J ,et al.Monofluorinated Cyclic EthersEnable Fast Ion Transport in Low-Temperature Lithium Metal Batteries[J].[2025-12-11].

[10] Zhao Z , Wang A , Chen A ,et al.Leveraging Ion Pairing andTransport in Localized High-Concentration Electrolytes for Reversible LithiumMetal Anodes at Low Temperatures[J].Angewandte Chemie International Edition,2024, 63(45):10.DOI:10.1002 / anie.202412239.

[11] Jiang, H., Yang, C., Chen, M., Liu, X., Yin, L., You, Y.,&Lu, J.(2023). Electrophilically Trapping Water for Preventing Polymerization ofCyclic Ether Towards Low‐Temperature Li Metal Battery. Angewandte Chemie, 135(14). https: / / doi.org / 10.1002 / ange.202300238

[12] Ma, T., Ni, Y., Wang, Q., Zhang, W., Jin, S., Zheng, S., Yang,X., Hou, Y., Tao, Z.,&Chen, J. (2022). Optimize Lithium Deposition at LowTemperature by Weakly Solvating Power Solvent. Angewandte Chemie, 134(39).https: / / doi.org / 10.1002 / ange.202207927

[13] Liu X , Zhang J , Yun X ,et al.Anchored Weakly‐SolvatedElectrolytes for High‐Voltage and Low‐Temperature Lithium‐ion Batteries[J].Angewandte Chemie, 2024, 136(36).DOI:10.1002 / ange.202406596.

[14] Cheng, L., Wang, Y., Yang, J., Tang, M., Zhang, C., Zhu, Q.,Wang, S., Li, Y., Hu, P.,&Wang, H. (2022). An Ultrafast and Stable Li‐MetalBattery Cycled at -40 °C. Advanced Functional Materials, 33(11). https: / / doi.org / 10.1002 / adfm.202212349

[15] Han Z, Li S, Sun M, et al. Fluorobenzene diluted low-density electrolyte for high-energy density and high-performance lithium-sulfur batteries[J]. Journal of Energy Chemistry: English Edition, 2022(5):752-761.

[16] Wang, Z., Wang, Y., He, X., Geng, M., & Zhang, B. (2025). Designing bi-layer electrode-electrolyte interfaces with an asymmetric ether to enable wide-temperature lithium metal batteries. Nature Communications, 16(1). https: / / doi.org / 10.1038 / s41467-025-65938-y

[17] Cai G, Holoubek J, Li M, et al. Solvent selection criteria for temperature-resilient lithium-sulfur batteries[J]. Proceedings of the National Academy of Sciences of the United States of America. 2022(28):119.

[18] Holoubek J, Liu H, Wu Z, et al. Tailoring Electrolyte Solvation for Li Metal Batteries Cycled at Ultra-Low Temperature[J]. Nature Energy, 2021, 2021(3). DOI:10.1038 / s41560-021-00783-z.

[19] Wang, J., Li, G., Wang, Q., Huang, L., Gan, https: / / doi.org / 10.1016 / j.ensm.2023.102956

[20] Sun T , Zhang W , Shi M ,et al.Intramolecular Hydrogen BondsWeaken Interaction Between Solvents and Small Organic Molecules TowardsSuperior Lithium‐Organic Batteries[J].Angewandte Chemie, 2025, 137(5).DOI:10.1002 / ange.202416845.

[21] Zheng Y , Qian T , Ji H ,et al.Accelerating Ion Dynamics UnderCryogenic Conditions by the Amorphization of Crystalline Cathodes[J].AdvancedMaterials, 2021.DOI:10.1002 / adma.202102634. Example 3 Fabrication of a lithium-ion battery capable of operating over a wide temperature range.

[0077] The positive electrode sheet was prepared according to Example 2.

[0078] Preparation of the negative electrode: 2,3,7,8-tetraaminophenazine-1,4,6,9-tetraone (active material) (loading amount 5 mg / cm³) 2The carbon black (conductive additive) and polytetrafluoroethylene (binder) were weighed in a mass ratio of 6:3:1, ground evenly in a mortar, and anhydrous ethanol was added as a dispersant and ground again to form a uniform film. The film was dried in an oven at 80°C for 12 hours, cut into round pieces with a diameter of 12 mm, and pressed onto a copper grid.

[0079] Pre-lithiation of the negative electrode: The lithium metal battery was assembled in the following order: positive electrode shell, negative electrode, separator, lithium metal, gasket, spring sheet, and negative electrode shell. The electrolyte was the electrolyte described in Example 1, with a dosage of 80 μL. The separator consisted of one layer of Celgard 2500 and one layer of glass fiber separator. The assembled lithium metal battery was subjected to constant current charge-discharge testing at 25°C and a current density of 0.2 A / g, with a voltage range of 0.01 V-1.9 V, for 3 cycles. The final cycle was constant current discharge to 0.01 V, at which point the negative electrode was in a lithium-intercalated state. The battery was then disassembled, the negative electrode was removed, and placed in the electrolyte described in Example 1. It was washed three times and then allowed to dry under an argon atmosphere.

[0080] Assembly of the full battery: The assembly is carried out in the following order: positive electrode shell, positive electrode sheet, separator, pre-lithiated negative electrode sheet, gasket, spring sheet, and negative electrode shell. The electrolyte is the electrolyte described in Example 1, with a dosage of 80 μL, and the separator consists of one layer of Celgard 2500 and one layer of glass fiber separator.

[0081] Figure 14 Cycling data for the lithium-ion battery in Example 3 at 25°C and -70°C are presented. It can be seen that the initial capacity release of the lithium-ion battery at 25°C is 328 mAh / g, compared to 345 mAh / g for the lithium metal battery in Example 1, representing a capacity loss of less than 5%, demonstrating good compatibility between the positive and negative electrodes and the electrolyte of this lithium-ion battery. Furthermore, after 50 cycles, the capacity retention rate is 88.5% at 25°C and 98.7% at -70°C. This indicates that the lithium-ion battery constructed using the electrolyte of this invention, which can adapt to a wide temperature range, exhibits good cycle stability at both room temperature and low temperatures.

[0082] The above embodiments are merely examples. For instance, when the lithium battery is a lithium metal battery, the positive electrode active material used can be one or more of lithium cobalt oxide, lithium iron phosphate, binary and ternary electrode materials based on nickel cobalt manganese, organic electrode materials, hard carbon, carbon black, lithium titanate, silicon, bismuth, and tin; when the lithium battery is a lithium-ion battery, the positive electrode active material used can be one of lithium cobalt oxide, lithium iron phosphate, binary and ternary electrode materials based on nickel cobalt manganese, and organic electrode materials, and the negative electrode active material can be one of organic electrode materials, hard carbon, carbon black, lithium titanate, silicon, bismuth, and tin; taking organic electrode materials as an example, they can be organic electrode materials already reported in the prior art, such as quinone organic electrode materials (e.g.: Benzoquinone, o-benzoquinone, 1,2-naphthoquinone, 1,4-naphthoquinone, 2,6-naphthoquinone, 1,4,5,8-naphthodione, anthraquinone, phenanthrenequinone, 1,4,9,10-anthratrione, 1,4,5,8-anthratrione, 1,4,5,8,9,10-anthrahexane, 4aH-anthra-2,9,10-trione, tetraphenyl-1,4-dione, tetrabenzoquinone, 1,4,6,11-naphthoquinone tetraone, 5a,11alpha-dihydrotetraphenyl-5,6,11,12-tetraone, pyrene-4,5,9,10-tetraone, benzophenanthrene-1,4-dione, 6,13-pentabenzoquinone, perylene-3,10-dione, hexahexanecycloketone), organic sulfur electrode materials (such as: poly(pentabenzotrione sulfur)). Organic electrode materials include: compounds, poly(hexaazatriphenylene sulfide), phenazine-based organic electrode materials (e.g., phenazine), aniline-based organic electrode materials (e.g., polyaniline), aza-fused-ring organic electrode materials (e.g., quinoline, 1,4,6,9-phenylazinetetraone, hexaazanaphthoquinone), carboxylic acid derivative organic electrode materials (e.g., lithium terephthalate, lithium 4,4′-dicarboxystyrene anhydride, 1,4,5,8-naphthalenetetracarboxylic anhydride, 3,4,9,10-tetracarboxylic anhydride, 3,4,9,10-tetracarboxylic acid diimide, N,N'-dimethyl-1,4,5,8-naphthalenetetracarboxylic acid diimide), and conjugated aromatic ketone organic electrode materials (e.g., anthrone, 9-fluorenone, 5,6,7,9,14,16,1...). 7,18-Heptane-Octanone, 5,6,7,9,10,11,16,17,18,20,21,22-Nonane-Dodecanone), free radical polymer organic electrode materials (e.g., poly(2,2,6,6-tetramethylpiperidin-1-oxy-4-ylmethacrylate)), conjugated polymer organic electrode materials (e.g., 2,7-bis(9H-carbazol-9-yl)pyrene-4,5,9,10-tetraone), metal-organic framework electrode materials (e.g., coordination polymers of copper-2,3,7,8-tetraaminophenazine-1,4,6,9-tetraone, coordination polymers of nickel-2,3,5,6-tetraaminobenzene, and coordination polymers of copper-2,3,5,6-tetraaminobenzoquinone).

[0083] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. The application of a mixed organic solvent as a solvent for an energy storage battery electrolyte, characterized in that, The mixed organic solvent is composed of tetrahydrofuran, 1,3-dioxolane, and 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether, wherein the volume percentage content of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether in the mixed organic solvent is 10% to 50%.

2. The application as described in claim 1, characterized in that, The electrolyte can operate in a wide temperature range of -130 to 60°C; Preferably, the electrolyte is capable of operating at a temperature of -130 to -40°C; more preferably, the electrolyte is capable of operating at a temperature of -130 to -80°C.

3. The application as described in claim 1, characterized in that, In the mixed organic solvent, the volume ratio of tetrahydrofuran to 1,3-dioxolane is (1~5):(1~5).

4. The application as described in claim 1, characterized in that, The electrolyte is obtained by dissolving lithium salt in the mixed organic solvent.

5. The application as described in claim 4, characterized in that, The lithium salt is one or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium difluorophosphate, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium bis(oxalateborate), lithium difluorooxalateborate, lithium trifluoromethanesulfonate, lithium hexafluoroarsenate, lithium perchlorate, lithium nitrate, lithium fluoride, lithium chloride, lithium bromide, lithium carbonate, and lithium sulfate.

6. The application as described in claim 4, characterized in that, The concentration of lithium salt in the electrolyte is 0.5 ~ 3 M.

7. An electrolyte, characterized in that, The solvent is a mixed organic solvent composed of tetrahydrofuran, 1,3-dioxolane and 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether; the volume percentage content of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether in the mixed organic solvent is 10% to 50%.

8. A lithium battery, characterized in that, Its electrolyte is a mixed organic solvent composed of tetrahydrofuran, 1,3-dioxolane and 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether; the volume percentage content of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether in the mixed organic solvent is 10% to 50%.

9. The lithium battery as described in claim 8, characterized in that, The lithium battery is a lithium metal battery or a lithium-ion battery. Preferably, when the lithium battery is a lithium metal battery, the positive electrode active material used is one or more of lithium cobalt oxide, lithium iron phosphate, binary and ternary electrode materials based on nickel cobalt manganese, organic electrode materials, hard carbon, carbon black, lithium titanate, silicon, bismuth, and tin, and the negative electrode is lithium metal. When the lithium battery is a lithium-ion battery, the positive electrode active material used is one of lithium cobalt oxide, lithium iron phosphate, binary and ternary electrode materials based on nickel cobalt manganese, and organic electrode materials, and the negative electrode active material is one of organic electrode materials, hard carbon, carbon black, lithium titanate, silicon, bismuth, and tin. More preferably, in the lithium metal battery, the areal loading of the positive electrode active material in the positive electrode sheet is 0.2~200 mg / cm². 2 ; In the lithium-ion battery, the areal loading of the positive electrode active material in the positive electrode sheet is 0.2~200 mg / cm². 2 The areal loading of the negative electrode active material in the negative electrode sheet is 0.2~200 mg / cm². 2 ; The organic electrode material is selected from quinone organic electrode materials, organosulfur electrode materials, phenazine organic electrode materials, aniline organic electrode materials, nitrogen-containing fused ring organic electrode materials, carboxylic acid derivative organic electrode materials, conjugated aromatic ketone organic electrode materials, free radical polymer electrode materials, conjugated polymer organic electrode materials, and metal-organic framework electrode materials.

10. The application of the lithium battery as described in claim 8 or 9 in a wide temperature range of -130 to 60°C; Preferably, the application is performed at a temperature of -130 to -40°C; more preferably, the application is performed at a temperature of -130 to -80°C.

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