CN-120199905-B - Low-temperature sodium metal battery electrolyte and preparation method and application thereof

Abstract

The application discloses low-temperature sodium metal battery electrolyte, and a preparation method and application thereof, and belongs to the technical field of energy storage batteries. The low-temperature sodium metal battery electrolyte provided by the application is prepared by dissolving sodium salt in ethylene glycol diethyl ether (EGDEE) and cyclopentyl methyl ether (CPME). The ethyl chain at the EGDEE tail end in the electrolyte prepared by the application allows more anions to enter the first solvation sheath of the hybridization solvent, so that the ionic conductivity at the ultralow temperature of-40 ℃ is greatly improved. Meanwhile, the novel anion-rich solvation structure which can be spontaneously formed at low temperature accelerates the kinetic rate of Na + . Meanwhile, the application adopts two organic solvents with acyclic ether structures, solves the problem of easy ring opening in the prior art, simultaneously shows ultralow sodium nucleation overpotential, can uniformly deposit sodium, ensures that the sodium has excellent reversibility and cycle stability at room temperature and low temperature, has excellent electrochemical performance, and ensures that the prepared sodium metal battery has wide application prospect.

Inventors

• WU CHAO
• BAI YUN
• LIU HAOXUAN

Assignees

• 上海理工大学

Dates

Publication Date

20260512

Application Date

20250331

Claims (8)

1. 1. A low-temperature sodium metal battery electrolyte, which is characterized by comprising an organic solvent and sodium salt dissolved in the organic solvent; The organic solvent is prepared by mixing ethylene glycol diethyl ether and cyclopentyl methyl ether, and the cyclopentyl methyl ether accounts for 5-20% of the volume fraction of the organic solvent.
2. 2. The low temperature sodium metal battery electrolyte according to claim 1, wherein the sodium salt is sodium hexafluorophosphate.
3. 3. The low temperature sodium metal battery electrolyte according to claim 2, wherein the sodium salt concentration is 0.8-1.2mol/L.
4. 4. The low temperature sodium metal battery electrolyte according to claim 3, wherein the sodium salt concentration is 1mol/L.
5. 5. The low temperature sodium metal battery electrolyte according to claim 1, wherein the volume fraction of the cyclopentyl methyl ether in the organic solvent is 10%.
6. 6. A method for preparing the low-temperature sodium metal battery electrolyte according to any one of claims 1 to 5, comprising: and dissolving sodium salt in a mixed solvent prepared from ethylene glycol diethyl ether and cyclopentyl methyl ether to obtain the low-temperature sodium metal battery electrolyte.
7. 7. Use of the low temperature sodium metal battery electrolyte according to any one of claims 1-5 or the low temperature sodium metal battery electrolyte made by the preparation method according to claim 6 for the preparation of sodium metal batteries.
8. 8. A sodium metal battery comprising the low temperature sodium metal battery electrolyte of any one of claims 1-5 or made by the method of making of claim 6.

Description

Low-temperature sodium metal battery electrolyte and preparation method and application thereof Technical Field The application belongs to the technical field of energy storage batteries, and particularly relates to a low-temperature sodium metal battery electrolyte, a preparation method and application thereof. Background The sodium metal battery has the advantages of higher theoretical capacity (1166 mAh g -1), relatively lower oxidation-reduction potential (2.71V), long cycle life, environmental friendliness, high cost effectiveness and the like, and has large-scale application potential in the field of energy storage. In order to meet the requirement of robust and safe operation under low temperature conditions in practical application, the electrolyte plays a vital role. Ester and ether solvents are generally used in the existing electrolyte, the growth of dendrites is promoted by ester groups, serious side reactions occur, and ether electrolytes are widely used due to excellent oxidation stability and fewer side reactions. However, the prior art generally adopts cyclic ether solvents, which are easy to carry out ring-opening reaction with sodium salt, so that the electrochemical stability is reduced. Therefore, development of an electrolyte excellent in combination properties is required to enhance the wide application of sodium metal batteries at low temperatures. For example, the prior art with the application publication number of CN 117613395A discloses a high-performance sodium/potassium ion battery electrolyte which comprises 0.5mol/L-5mol/L electrolyte (sodium hexafluorophosphate), 10-50% of weak polar solvent (1, 3-dioxolane) accounting for the volume fraction of the solvent and 90-50% of nonpolar solvent (ethylene glycol dibutyl ether) accounting for the volume fraction of the solvent, so that the rate performance and the battery cycle life of a sodium battery can be effectively improved. However, the existing sodium ion battery electrolyte has the following problems that firstly, in a system, sodium salt plays a role of Lewis base, cyclic ether ring opening is easy to cause, and the stability of a battery is reduced, and secondly, the use of a solvent under a low-temperature environment is limited due to the selection of the solvent. Disclosure of Invention The application discloses low-temperature sodium metal battery electrolyte and a preparation method and application thereof, and aims to solve the technical problems that the existing electrolyte is poor in circulation stability, does not have low-temperature usability and the like. In order to achieve the above object, the technical scheme of the present application is as follows: the first aspect of the application provides a low-temperature sodium metal battery electrolyte, which comprises an organic solvent and sodium salt dissolved in the organic solvent; the organic solvent is prepared by mixing ethylene glycol diethyl ether and cyclopentyl methyl ether. With reference to the first aspect, preferably, the sodium salt is sodium hexafluorophosphate. Preferably in combination with the first aspect, the sodium salt concentration is 0.8-1.2mol/L. With reference to the first aspect, preferably, the sodium salt concentration is 1mol/L. With reference to the first aspect, preferably, the volume fraction of the cyclopentyl methyl ether in the organic solvent is 5-20%. With reference to the first aspect, preferably, the volume fraction of the cyclopentyl methyl ether in the organic solvent is 10%. A second aspect of the present application provides a method for preparing the low-temperature sodium metal battery electrolyte according to the first aspect, the method comprising: and dissolving sodium salt in a mixed solvent prepared from ethylene glycol diethyl ether and cyclopentyl methyl ether to obtain the low-temperature sodium metal battery electrolyte. The third aspect of the application provides the low-temperature sodium metal battery electrolyte of the first aspect or the application of the low-temperature sodium metal battery electrolyte prepared by the preparation method of the second aspect in sodium metal batteries. According to a fourth aspect of the application, there is provided a sodium metal battery comprising the low temperature sodium metal battery electrolyte of the first aspect or the low temperature sodium metal battery electrolyte produced by the method of production of the second aspect. Compared with the prior art, the embodiment of the application has the advantages or beneficial effects that at least the advantages or beneficial effects comprise: The low-temperature sodium metal battery electrolyte provided by the application is prepared by dissolving sodium salt in ethylene glycol diethyl ether (EGDEE) and cyclopentyl methyl ether (CPME), on one hand, an ethyl chain at the end of EGDEE allows more anions to enter a first solvation sheath of a hybrid solvent, so that cation-solvent coordination is reduced, sodium ion-