Low-temperature sodium ion battery
By using ultra-low-temperature electrolyte containing sodium salt, non-aqueous solvent and film-forming additives in sodium ion batteries, the problem of difficult sodium ion batteries to charge normally in low-temperature environments is solved, and the battery can operate at extremely low-temperature conditions is achieved.
Patent Information
- Application Number
- CN202411714570.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-27
- Publication Date
- 2025-02-28
AI Technical Summary
Sodium ion batteries are difficult to charge normally in low temperature environments, resulting in slowing down the kinetics of electrochemical reactions, challenging the interface stability between electrodes and electrolytes, and reducing the diffusion rate of sodium ions, which in turn leads to a decline in the overall performance of the battery.
An ultra-low-temperature charged electrolyte is used, which includes sodium salts, non-aqueous solvents (such as nitriles and chain carboxylic acid esters) and film-forming additives, and improves the performance of the battery in a low-temperature environment by optimizing the composition of the electrolyte.
At -40℃, -30℃ and -20℃, the capacity retention rate of sodium ion batteries reaches more than 45%, more than 65% and more than 85%, respectively, which significantly improves the charging performance of the battery in low-temperature environments.
Smart Images
Figure CN119542549A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of sodium ion batteries, and in particular to the preparation and application of a sodium ion battery suitable for ultra-low temperature charging. Background Art
[0002] As an ideal candidate for the next generation of large-scale energy storage technology, sodium-ion batteries have attracted widespread attention from the industry due to their cost advantages. However, their performance in practical applications is severely limited by geographical factors. Under certain extreme conditions, the low-temperature performance problems faced by sodium-ion batteries have become an urgent technical obstacle, which urgently needs major technological innovations to overcome. Under low-temperature conditions, the electrochemical reaction kinetics of SIBs slow down significantly, the stability of the electrode and electrolyte interface is challenged, and the diffusion rate of sodium ions in the electrode material is reduced, which together lead to the decline of the overall performance of the battery. Therefore, optimizing the low-temperature performance of sodium-ion batteries and rationally designing and optimizing the electrolyte system and electrode materials have become a crucial task, which has far-reaching significance for promoting their widespread application. Summary of the invention
[0003] The object of the present invention is to provide a sodium ion battery suitable for ultra-low temperature charging, thereby solving the problems existing in the above-mentioned technology.
[0004] In order to solve the problem that sodium ion batteries are difficult to charge normally at low temperatures, the technical solution adopted by the present invention is as follows:
[0005] The present invention discloses a low-temperature sodium ion battery, comprising a positive electrode, a negative electrode, a separator, and an electrolyte, characterized in that the electrolyte is an electrolyte for ultra-low temperature charging, and the low-temperature electrolyte comprises a sodium salt, a non-aqueous solvent, and a film-forming additive; wherein the non-aqueous solvent is composed of one of the nitrile substances shown in the following formula I and one or more of the chain carboxylic acid esters shown in the following formula II.
[0006]
[0007] Preferably, in terms of mass percentage, the sodium salt in the low-temperature electrolyte is 10% to 30%, the nitrile solvent is 10% to 30%, the chain carboxylic acid ester solvent is 30% to 80%, and the film-forming additive is 1% to 10%.
[0008] Further preferably, the electrolyte comprises sodium salt, non-aqueous solvent and film-forming additive, wherein, by mass percentage, sodium salt is 15% to 20%, nitrile solvent is 15% to 18%, and chain carboxylic acid ester solvent is 35% to 70%.
[0009] 0%, and film-forming additives are 1% to 7%.
[0010] Preferably, the sodium salt is selected from one or more of sodium tetrafluoroborate, sodium hexafluorophosphate, sodium bis(trifluoromethylsulfonyl)imide and sodium bis(trifluoromethylsulfonyl)imide.
[0011] More preferably, the sodium salt is selected from bis(trifluoromethylsulfonyl)imide sodium salt.
[0012] Preferably, the film-forming additive is one or more of 3-(2-methoxyethoxy)tetrahydrothiophene 1,1-dioxide, 3-ethoxytetrahydrothiophene 1,1-dioxide, 3-isopropoxytetrahydrothiophene 1,1-dioxide, and 3-methoxytetrahydrothiophene 1,1-dioxide, and its chemical formula is shown in Formula III below.
[0013]
[0014] More preferably, the film-forming additive is 3-(2-methoxyethoxy)tetrahydrothiophene 1,1-dioxide, and its content is controlled at 2% to 6%.
[0015] The beneficial effects of the present invention are as follows: the present invention discloses a low-temperature sodium ion battery, comprising a positive electrode, a negative electrode, a separator, and an electrolyte. The electrolyte is an electrolyte for ultra-low temperature charging, and the electrolyte comprises a sodium salt, a non-aqueous solvent, and a film-forming additive. The low-temperature electrolyte for ultra-low temperature charging comprises a lithium salt, a non-aqueous solvent, and a film-forming additive, wherein the non-aqueous solvent comprises a nitrile substance and one or more chain carboxylate substances. Compared with ordinary sodium ion batteries, the low-temperature sodium ion battery of the present invention can achieve a capacity retention rate of more than 45% at -40 degrees Celsius, a capacity retention rate of more than 65% at -30°C, and more than 85% at -20°C. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 is the capacity-voltage curve of Example 1 of the present invention at -40°C and 0.2c;
[0017] Figure 2 is the capacity-voltage curve of Example 1 of the present invention at -30°C and 0.2C;
[0018] Figure 3 This is the capacity-voltage curve of Example 1 of the present invention at -20°C and 0.2C. DETAILED DESCRIPTION
[0019] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation methods described herein are only used to explain the present invention and are not used to limit the present invention.
[0020] Example 1
[0021] A low-temperature sodium ion battery comprises a positive electrode, a negative electrode, a diaphragm, and an electrolyte. The electrolyte is an electrolyte for ultra-low temperature charging, and the electrolyte comprises a sodium salt, a non-aqueous solvent, and a film-forming additive. The preparation method of the electrolyte is as follows: in a standard glove box, high-purity argon gas is filled (water, oxygen content ≤1ppm), butyronitrile (AN) and ethyl acetate (EA) are used as non-aqueous solvents, sodium salt of bistrifluoromethylsulfonyl imide (NaTFSI) is used as a sodium salt, and methyl (3-(methylsulfonyl)propyl) carbonate and 3-(methylsulfonyl)propyl acetate are used as film-forming additives. The preparation method is as follows: 4.5 g of butyronitrile and 19.5 g of ethyl acetate (EA) are mixed, and then 1 g of 3-(2-methoxyethoxy)tetrahydrothiophene 1,1-dioxide, 0.5 g of 3-ethoxytetrahydrothiophene 1,1-dioxide, and 4.5 g of sodium bistrifluoromethylsulfonyl imide (NaTFSI) are added to the solution, and the mixture is stirred evenly to obtain a low-temperature electrolyte NB888.
[0022] Using the above-configured NB888 as the electrolyte, sodium nickel iron manganese oxide as the positive electrode, and hard carbon as the negative electrode, a 1.1Ah soft-pack sodium ion battery was configured for electrochemical testing. Figure 1 The capacity-voltage curve of the sodium-ion battery at -40°C is shown. When discharged at a constant current of 0.2c, its charging capacity is 45.2% of its normal temperature capacity. Its -30°C low temperature capacity-voltage curve is shown in Figure 1. Figure 2 As shown, when discharged at a current of 0.2c, the NB888 electrolyte can still release 71.1% of its normal temperature capacity at a low temperature of -30°C. Figure 3 The -20°C capacity-voltage curve of NB888 electrolyte is shown, and the capacity retention is 87.2%.
[0023] Example 2
[0024] A low-temperature sodium ion battery comprises a positive electrode, a negative electrode, a diaphragm, and an electrolyte. The electrolyte is an electrolyte for ultra-low temperature charging, and the electrolyte comprises a sodium salt, a non-aqueous solvent, and a film-forming additive. The preparation method of the electrolyte is as follows: in a standard glove box, high-purity argon gas is filled (water, oxygen content ≤1ppm), succinonitrile (SN) and ethylene carbonate (EC) are used as non-aqueous solvents, sodium hexafluorophosphate is used as sodium salt, and 3-(2-methoxyethoxy)tetrahydrothiophene 1,1-dioxide and 3-isopropoxytetrahydrothiophene 1,1-dioxide are used as film-forming additives. The preparation method is as follows: 3.5 g of succinonitrile and 20.5 g of ethylene carbonate are mixed, and then 1 g of 3-(2-methoxyethoxy)tetrahydrothiophene 1,1-dioxide, 0.5 g of 3-isopropoxytetrahydrothiophene 1,1-dioxide, and 7.5 g of sodium hexafluorophosphate are added to the solution, and the mixture is stirred well to obtain a low-temperature electrolyte NB887.
[0025] The above-configured NB887 was used as the electrolyte, sodium nickel iron manganese oxide was used as the positive electrode, and hard carbon was used as the negative electrode to configure a 1.1Ah sodium ion battery for electrochemical testing. At -40°C, the constant current discharge was 0.2c, and its charging capacity was 43.2% of the normal temperature capacity. At -30°C, the NB887 electrolyte was discharged at a current of 0.2c, and it could still release 70.5% of the normal temperature capacity at a low temperature of -30°C. At -20°C, the capacity remained at 85.8%.
[0026] Example 3
[0027] A low-temperature sodium ion battery comprises a positive electrode, a negative electrode, a diaphragm and an electrolyte. The electrolyte is an electrolyte for ultra-low temperature charging, and the electrolyte comprises a sodium salt, a non-aqueous solvent and a film-forming additive. The preparation method of the electrolyte is as follows: in a standard glove box, high-purity argon gas is filled (water, oxygen content ≤1ppm), succinonitrile (SN) and ethyl acetate (EA) are used as non-aqueous solvents, sodium bis(fluorosulfonyl)imide is used as sodium salt, and 3-isopropoxytetrahydrothiophene 1,1-dioxide and 3-methoxytetrahydrothiophene 1,1-dioxide are used as film-forming additives. The preparation method is as follows: 5.5g of succinonitrile (SN) and 17.5g of ethyl acetate (EA) are mixed, and then 1.5g of 3-isopropoxytetrahydrothiophene 1,1-dioxide, 0.8g of 3-methoxytetrahydrothiophene 1,1-dioxide, and 4.5g of sodium bis(fluorosulfonyl)imide are added to the solution, and the mixture is stirred well to obtain a low-temperature electrolyte NB886.
[0028] The above-configured NB886 was used as the electrolyte, sodium nickel iron manganese oxide was used as the positive electrode, and hard carbon was used as the negative electrode. A 1.1Ah sodium ion battery was configured for electrochemical testing. At -40°C, the constant current discharge was 0.2c, and its charging capacity was 44.3% of the normal temperature capacity. At -30°C, the NB886 electrolyte was discharged at a current of 0.2c, and it could still release 68.9% of the normal temperature capacity at a low temperature of -30°C. At -20°C, the capacity remained at 86.2%.
Claims
1. A low-temperature sodium ion battery, comprising a positive electrode, a negative electrode, a separator, and an electrolyte, characterized in that: The electrolyte is an ultra-low temperature charging electrolyte, comprising a sodium salt, a non-aqueous solvent and a film-forming additive; wherein the non-aqueous solvent is composed of one of the nitrile substances shown in the following formula I and one or more of the chain carboxylic acid esters shown in the following formula II:
2. A low-temperature sodium ion battery according to claim 1, characterized in that: The electrolyte comprises sodium salt, non-aqueous solvent and film-forming additive, wherein, by mass percentage, sodium salt is 10% to 30%, nitrile solvent is 10% to 30%, chain carboxylic acid ester solvent is 30% to 80%, and film-forming additive is 1% to 10%.
3. A low-temperature sodium ion battery according to claim 2, characterized in that: The electrolyte comprises sodium salt, non-aqueous solvent and film-forming additive, wherein, by mass percentage, sodium salt accounts for 15% to 20%, nitrile solvent accounts for 15% to 18%, chain carboxylic acid ester solvent accounts for 35% to 70%, and film-forming additive accounts for 1% to 7%.
4. A low-temperature sodium ion battery according to claim 1 or 2, characterized in that: The sodium salt is selected from one or more of sodium tetrafluoroborate, sodium hexafluorophosphate, sodium bis(trifluoromethylsulfonyl)imide and sodium bis(trifluoromethylsulfonyl)imide.
5. A low-temperature sodium ion battery according to claim 4, characterized in that: The sodium salt is selected from bis(trifluoromethylsulfonyl)imide sodium salt.
6. A low-temperature sodium ion battery according to claim 1 or 2, characterized in that: The film-forming additive is one or more of 3-(2-methoxyethoxy)tetrahydrothiophene 1,1-dioxide, 3-ethoxytetrahydrothiophene 1,1-dioxide, 3-isopropoxytetrahydrothiophene 1,1-dioxide, and 3-methoxytetrahydrothiophene 1,1-dioxide, and its chemical formula is shown in the following formula III:
7. A low-temperature sodium ion battery according to claim 6, characterized in that: The film-forming additive is 3-(2-methoxyethoxy)tetrahydrothiophene 1,1-dioxide, and its content is controlled at 2% to 6%.