Preparation method and application of electrolyte for high-performance sodium-ion primary battery
By optimizing the composition and preparation method of the electrolyte for sodium-ion primary batteries, the problems of electrolyte explosion hazard and insufficient electrochemical performance have been solved, resulting in a high-safety and high-performance battery electrolyte suitable for sodium-ion primary batteries.
Patent Information
- Application Number
- CN202610742956.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-05-27
- Publication Date
- 2026-07-31
AI Technical Summary
Existing sodium-ion primary battery electrolytes pose a safety risk of explosion and have insufficient electrochemical performance, making it difficult to meet the requirements of high-performance batteries.
A combination of sodium perchlorate as sodium salt, ethylene carbonate and propylene carbonate as solvents, and fluorinated benzene as film-forming additive was used to optimize the electrolyte formulation. The electrolyte was prepared in an anhydrous environment, and appropriate amounts of other organic solvents and additives were added to form a high-performance sodium-ion primary battery electrolyte.
It significantly reduces the risk of sodium perchlorate explosion, improves the open-circuit voltage and discharge capacity of the battery, enhances low-temperature performance and rate characteristics, meets the pulse discharge requirements of primary batteries in a wide temperature range, and provides a highly safe and high-performance electrolyte.
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Figure CN122494692A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of sodium-ion primary battery electrolyte technology, and specifically to a method for preparing and applying a high-performance sodium-ion primary battery electrolyte. Background Technology
[0002] Currently, primary batteries hold an irreplaceable position in scenarios such as the Internet of Things, medical electronics, and automotive assistance systems. Their wide range of applications and huge demand make them an important consumer market. Taking China's button battery industry as an example, the annual output exceeds 10 billion units, with Yiwu accounting for 7% of the country's total small commodity trade, corresponding to an annual demand of approximately 300-500 million units. Compared to lithium batteries, sodium-ion batteries have a significant advantage in cost control—both the cathode material and the anode metallic sodium have lower production costs, which will strongly promote the large-scale development of primary batteries. Especially in sodium-ion battery systems, layered oxide cathode materials show outstanding potential: their core advantages are concentrated in four aspects: cost-effectiveness, low-temperature performance, safety performance, and application scenarios.
[0003] Due to the low desolvation energy of sodium ions and the high ionic conductivity of the electrolyte, sodium-ion batteries can still discharge stably in cold environments (such as high-altitude regions and outdoor equipment in winter), meeting the low-temperature performance requirements of primary batteries after long-term storage. Layered oxides, with their open two-dimensional ion channel structure, can achieve rapid ion diffusion, supporting high-rate discharge above 5C, making them particularly suitable for scenarios requiring pulsed discharge. Furthermore, this material system combines high operating voltage and energy density, fully meeting the capacity release requirements of primary batteries.
[0004] The core requirement for electrolytes in primary batteries lies in their high voltage characteristics, because under the same system conditions, the higher the voltage, the greater the capacity the battery can release. Therefore, compared to sodium hexafluorophosphate, sodium perchlorate has a greater advantage in primary battery applications due to its higher open-circuit voltage. However, sodium perchlorate itself poses a safety risk of explosion. Therefore, preparing a safe and electrochemically effective electrolyte for high-performance sodium-ion primary batteries is a technical problem to be solved in this field. Summary of the Invention
[0005] The first objective of this application is to prepare an electrolyte for high-performance sodium-ion primary batteries, which improves electrochemical performance while ensuring safe production, thereby enabling the effective use of primary batteries.
[0006] To achieve the above objectives, this application adopts the following technical solution: An electrolyte for high-performance sodium-ion primary batteries comprises a sodium salt, an organic solvent, and a film-forming additive. The sodium salt includes at least sodium perchlorate, the organic solvent includes at least ethylene carbonate and propylene carbonate, and the mass ratio of ethylene carbonate to propylene carbonate is 1:1. The film-forming additive includes at least fluorinated benzene.
[0007] Further settings are as follows: In addition to sodium perchlorate, the sodium salt may also contain one or more of sodium hexafluorophosphate, sodium tetrafluoroborate, sodium difluorooxalate borate, and sodium difluorophosphate.
[0008] Based on the total mass of the electrolyte, the sodium salt content in the electrolyte is between 0.1% and 25% by mass.
[0009] The film-forming additive may include, in addition to fluorinated benzene, other additives such as one or more of fluoroethylene carbonate and vinylene carbonate.
[0010] Based on the total mass of the electrolyte, the mass content of the film-forming additive in the electrolyte is between 0.1% and 10%.
[0011] The organic solvent, in addition to ethylene carbonate and propylene carbonate, may also include other organic solvents, which may be selected from any one or more of chain carbonates, carboxylic acid esters, and ether solvents.
[0012] Preferably, the chain carbonate is selected from one or more of methyl ethyl carbonate, methyl propyl carbonate, dimethyl carbonate, and diethyl carbonate.
[0013] Preferably, the carboxylic acid ester is selected from one or more of ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, and propyl propionate.
[0014] Preferably, the ether solvent is selected from one or more of ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, and triethylene glycol dimethyl ether.
[0015] Based on the total mass of the electrolyte, the organic solvent contains 70%-90% by mass in the electrolyte.
[0016] The second aspect of this application aims to provide a method for preparing a high-performance sodium-ion primary battery electrolyte, comprising the following steps: (1) Prepare sodium perchlorate solution: In a glove box filled with argon and with a water content of less than 1 ppm, the mixture is cooled to below 15°C. Ethyl carbonate and propylene carbonate are mixed in a mass ratio of 1:1. Sodium perchlorate is added, and the mixture is shaken to dissolve the precipitate, resulting in a liquid sodium perchlorate solution. (2) Prepare the electrolyte: Adding other organic solvents and film-forming additives to the aforementioned prepared sodium perchlorate solution yields an electrolyte for high-performance sodium-ion primary batteries.
[0017] The applicant discovered through research that by mixing ethylene carbonate and propylene carbonate in a 1:1 mass ratio as a solvent to prepare sodium perchlorate electrolyte, the risk of sodium perchlorate being prone to explosion can be significantly reduced, and the solution is easy to store.
[0018] The third objective of this application is to provide an application of the aforementioned prepared electrolyte in a sodium-ion primary battery, specifically: using a layered oxide as the positive electrode material and a metallic sodium sheet as the negative electrode material to construct a sodium-ion primary battery with the electrolyte.
[0019] Compared with the prior art, the beneficial effects of this application are as follows: (1) This application uses sodium perchlorate instead of the conventional sodium hexafluorophosphate system, and its higher open circuit voltage can effectively improve the battery discharge capacity.
[0020] (2) This application uses a 1:1 mass ratio of ethylene carbonate and propylene carbonate as a solvent to prepare sodium perchlorate electrolyte, which can significantly reduce the risk of easy explosion and simplify the preparation and storage of electrolyte.
[0021] (3) This application introduces fluorinated benzene and fluoroethylene carbonate as additives to synergistically improve the wettability of the electrolyte to the cathode material; among them, fluorinated benzene shows outstanding performance in optimizing low-temperature performance, rate characteristics and safety performance, which can meet the needs of primary batteries for pulse discharge in a wide temperature range. This electrolyte design combines high performance and high safety, providing material support for the large-scale market application of primary batteries. Attached Figure Description
[0022] Figure 1 The discharge capacity of the electrolytes prepared for the examples and comparative examples is compared when applied to sodium-ion primary batteries. Detailed Implementation
[0023] The present application will be further explained below with reference to the accompanying drawings and embodiments. Unless otherwise specified, the raw materials and reagents used in the embodiments are all existing technologies in the field or commercially available products.
[0024] The mass percentages in the examples are based on the total mass of the electrolyte, representing the percentage of the electrolyte by mass of this component.
[0025] Example 1
[0026] An electrolyte for high-performance sodium-ion primary batteries has the following composition: Sodium perchlorate 10%.
[0027] Ethylene carbonate 20%.
[0028] 20% propylene carbonate.
[0029] 18% methyl ethyl carbonate.
[0030] Ethyl propionate 25%.
[0031] 5% fluoroethylene carbonate.
[0032] 2% fluorinated benzene.
[0033] Preparation method: In a glove box filled with argon and with a water content of less than 1 ppm, the mixture is cooled to below 15°C. Ethyl carbonate and propylene carbonate are mixed in a certain proportion, sodium perchlorate is added, and the mixture is placed in a drum mixer and shaken to dissolve the solution, resulting in a liquid sodium perchlorate solution.
[0034] Add ethyl methyl carbonate and ethyl propionate to the aforementioned sodium perchlorate solution; finally, add fluoroethylene carbonate and fluorinated benzene to the solution to obtain a high-performance sodium-ion primary battery electrolyte.
[0035] Example 2
[0036] An electrolyte for high-performance sodium-ion primary batteries has the following composition: Sodium perchlorate 10%.
[0037] Ethylene carbonate 20%.
[0038] 20% propylene carbonate.
[0039] 25% methyl ethyl carbonate.
[0040] Ethyl propionate 18%.
[0041] 5% fluoroethylene carbonate.
[0042] 2% fluorinated benzene.
[0043] Preparation method: Same as in Example 1 Example 3
[0044] An electrolyte for high-performance sodium-ion primary batteries has the following composition: Sodium perchlorate 15%.
[0045] Ethylene carbonate 20%.
[0046] 20% propylene carbonate.
[0047] 10% methyl ethyl carbonate.
[0048] Ethyl propionate 15%.
[0049] Dimethyl carbonate 10%.
[0050] 5% fluoroethylene carbonate.
[0051] 2% fluorinated benzene.
[0052] Preparation method: Same as in Example 1 Example 4
[0053] An electrolyte for high-performance sodium-ion primary batteries has the following composition: Sodium perchlorate 10%.
[0054] Ethylene carbonate 20%.
[0055] 20% propylene carbonate.
[0056] 15% methyl ethyl carbonate.
[0057] Ethyl acetate 20%.
[0058] 10% fluoroethylene carbonate.
[0059] 5% fluorinated benzene.
[0060] Preparation method: Same as in Example 1 Example 5
[0061] An electrolyte for high-performance sodium-ion primary batteries has the following composition: Sodium perchlorate 10%.
[0062] Ethylene carbonate 25%.
[0063] 25% propylene carbonate.
[0064] 10% methyl ethyl carbonate.
[0065] Ethyl propionate 10%.
[0066] Diethyl carbonate 10%.
[0067] 7% fluoroethylene carbonate.
[0068] 3% fluorinated benzene.
[0069] Preparation method: Same as in Example 1 An electrolyte for high-performance sodium-ion primary batteries prepared in Examples 1-5 was applied to a sodium-ion primary battery (O3 type oxygen layer), and its electrochemical performance was tested as shown in Examples 6-10.
[0070] Example 6
[0071] Battery Assembly: Using the electrolyte prepared in Example 1, batteries were assembled. O3-type layered oxide was used as the sodium-ion positive electrode material. The positive electrode sheet was formed by slurry preparation, coating, rolling, and cutting. A metallic sodium sheet was used as the negative electrode. The CR2032 button cell was fabricated in the following order: positive electrode shell – positive electrode sheet – separator – electrolyte – sodium sheet – nickel foam – negative electrode shell. The open-circuit voltage of the coin cell was first tested, and then discharged at 25°C at a 1C rate to 1.5V, and the discharge capacity was recorded.
[0072] Example 7
[0073] The preparation method is the same as in Example 6, except that the electrolyte prepared in Example 2 is used for battery assembly.
[0074] Example 8
[0075] The preparation method is the same as in Example 6, except that the electrolyte prepared in Example 3 is used for battery assembly.
[0076] Example 9
[0077] The preparation method is the same as in Example 6, except that the electrolyte prepared in Example 4 is used for battery assembly.
[0078] Example 10
[0079] The preparation method is the same as in Example 6, except that the electrolyte prepared in Example 5 is used for battery assembly.
[0080] Comparative Example 1 A sodium-ion primary battery electrolyte has the following composition: Sodium perchlorate 10%.
[0081] Ethylene carbonate 20%.
[0082] 20% propylene carbonate.
[0083] 20% methyl ethyl carbonate.
[0084] Ethyl propionate 25%.
[0085] 7% fluoroethylene carbonate.
[0086] Preparation method: Same as in Example 1, except that fluorinated benzene was not added.
[0087] Comparative Example 2 A sodium-ion primary battery electrolyte has the following composition: Sodium hexafluorophosphate 10%.
[0088] Ethylene carbonate 20%.
[0089] 20% propylene carbonate.
[0090] 18% methyl ethyl carbonate.
[0091] Ethyl propionate 25%.
[0092] 7% fluoroethylene carbonate.
[0093] 3% fluorinated benzene.
[0094] Preparation method: Same as in Example 1, except that sodium perchlorate is replaced with sodium hexafluorophosphate.
[0095] Comparative Example 3 A sodium-ion primary battery electrolyte has the following composition: Sodium perchlorate 10%.
[0096] Propylene carbonate 40%.
[0097] 18% methyl ethyl carbonate.
[0098] Ethyl propionate 25%.
[0099] 7% fluoroethylene carbonate.
[0100] 3% fluorinated benzene.
[0101] Preparation method: Same as in Example 1, except that 20% ethylene carbonate and 20% propylene carbonate are replaced with 40% propylene carbonate.
[0102] The sodium-ion primary battery electrolytes prepared in Comparative Examples 1-3 were applied to sodium-ion primary batteries (O3 type oxygen layer), and their electrochemical performance was tested, as shown in Comparative Examples 4-6.
[0103] Comparative Example 4 Battery Assembly: Using the electrolyte prepared in Comparative Example 1, batteries were assembled. O3-type layered oxide was used as the sodium-ion positive electrode material. The positive electrode sheet was formed by slurry preparation, coating, rolling, and cutting. A metallic sodium sheet was used as the negative electrode. The CR2032 button cell was fabricated in the following order: positive electrode shell – positive electrode sheet – separator – electrolyte – sodium sheet – nickel foam – negative electrode shell. The open-circuit voltage of the coin cell was first tested, and then discharged at 25℃ at a 1C rate to 1.5V, and the discharge capacity was recorded.
[0104] Comparative Example 5 The preparation method is the same as that of Comparative Example 4, except that the electrolyte prepared in Comparative Example 2 is used for battery assembly.
[0105] Comparative Example 6 The preparation method is the same as that of Comparative Example 4, except that the electrolyte prepared in Comparative Example 3 is used for battery assembly.
[0106] Performance testing: The batteries assembled in Examples 6-10 and Comparative Examples 4-6 were subjected to discharge capacity testing. The discharge capacity retention rate at 25°C and 1C was as follows: Figure 1 As shown: 1. A comparison of Examples 1-5 shows that when the electrolyte composition is (NaClO4 / EC / PC=10:25:25), it is more beneficial to the electrochemical performance. From the perspective of additives, the contents of FB and FEC show a parabolic linear change. The contents of FEC at 7% and FB at 3% are more beneficial to the performance. Excessive addition will lead to performance degradation.
[0107] 2. Comparing the electrolytes of Examples 1-5 with those of Comparative Examples 1-3, it can be seen that: (1) FB significantly improves open-circuit voltage and discharge capacity.
[0108] (2) NaPF6 has a significant disadvantage in capacity utilization compared to NaClO4.
[0109] (3) From the perspective of electrolyte formulation, the solvent capacity of (NaClO4 / EC / PC) is far superior to that of a single solvent, which also reflects the superiority of the electrolyte ratio in this application.
[0110] The above description is merely a preferred embodiment of this application and is used to illustrate this application. It does not limit the implementation of this application in any way. Therefore, equivalent substitutions, improvements, and modifications made without departing from the principles of this application are still included within the scope of the claims of this application.
Claims
1. An electrolyte for high-performance sodium-ion primary batteries, characterized in that: The film contains a sodium salt, an organic solvent, and a film-forming additive. The sodium salt includes at least sodium perchlorate, the organic solvent includes at least ethylene carbonate and propylene carbonate in a mass ratio of 1:1, and the film-forming additive includes at least fluorinated benzene.
2. The electrolyte for high-performance sodium-ion primary batteries according to claim 1, characterized in that: In addition to sodium perchlorate, the sodium salt also includes one or more of sodium hexafluorophosphate, sodium tetrafluoroborate, sodium difluorooxalate borate, and sodium difluorophosphate.
3. The electrolyte for high-performance sodium-ion primary batteries according to claim 1, characterized in that: Based on the total mass of the electrolyte, the sodium salt content in the electrolyte is between 0.1% and 25% by mass.
4. The electrolyte for high-performance sodium-ion primary batteries according to claim 1, characterized in that: In addition to fluorinated benzene, the film-forming additives also include one or more of fluoroethylene carbonate and vinylene carbonate.
5. The electrolyte for high-performance sodium-ion primary batteries according to claim 1, characterized in that: Based on the total mass of the electrolyte, the mass content of the film-forming additive in the electrolyte is between 0.1% and 10%.
6. The electrolyte for high-performance sodium-ion primary batteries according to claim 1, characterized in that: In addition to ethylene carbonate and propylene carbonate, the organic solvents also include any one or more of chain carbonates, carboxylic acid esters, and ether solvents.
7. The electrolyte for high-performance sodium-ion primary batteries according to claim 6, characterized in that: The chain carbonate is selected from one or more of methyl ethyl carbonate, methyl propyl carbonate, dimethyl carbonate, and diethyl carbonate; the carboxylic acid ester is selected from one or more of ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, and propyl propionate; the ether solvent is selected from one or more of ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, and triethylene glycol dimethyl ether.
8. The electrolyte for high-performance sodium-ion primary batteries according to claim 1, characterized in that: Based on the total mass of the electrolyte, the organic solvent contains 70%-90% by mass in the electrolyte.
9. A method for preparing the electrolyte for a high-performance sodium-ion primary battery as described in claim 1, characterized in that, Includes the following steps: (1) Prepare sodium perchlorate solution In a glove box filled with argon and with a water content of less than 1 ppm, the mixture is cooled to below 15°C. Ethyl carbonate and propylene carbonate are mixed in a mass ratio of 1:
1. Sodium perchlorate is added, and the mixture is shaken to dissolve the precipitate, resulting in a liquid sodium perchlorate solution. (2) Prepare electrolyte Adding other organic solvents and film-forming additives to the aforementioned prepared sodium perchlorate solution yields an electrolyte for high-performance sodium-ion primary batteries.
10. The application of the high-performance sodium-ion primary battery electrolyte of claim 1 in a sodium-ion primary battery.