Sodium ion electrolyte, secondary battery, preparation method and application

Abstract

The invention discloses a sodium ion electrolyte, a secondary battery, a preparation method and an application. This electrolytic solution comprises basic electrolytic solution and additive, and described basic electrolytic solution comprises sodium salt and flame retardant solvent; Described flame retardant solvent comprises phosphoric acid ester and fluorinated ether; Described additive comprises fluorine-containing additive; Described sodium salt is relative to The concentration of the basic electrolyte is 1-2mol/L; the concentration of the sodium salt relative to the phosphoric acid ester is 1.5-3mol/L; the volume ratio of the phosphoric acid ester to the fluoroether is 1:1 ~2:1; the content of the additive in the mass percentage of the basic electrolyte is greater than 0 and less than or equal to 5 wt%. The sodium ion battery prepared by the electrolyte of the present invention has good thermal stability, can form a stable SEI film and hinder the reaction between the electrode and the electrolyte, and has a charge-discharge performance equivalent to that of an electrolyte with carbonate as a solvent. low cost.

Description

technical field [0001] The invention relates to a sodium ion electrolyte, a secondary battery, a preparation method and an application. Background technique [0002] In recent years, due to the abundant sodium resources and low cost, it can be applied in large-scale energy storage in the future, and it has become a new hotspot in battery research. With the application of batteries in mobile phones, computers, electric vehicles and large-scale energy storage, the safety of battery systems has become the focus of the industry. Therefore, the safety of sodium ion electrolytes has also attracted the attention of researchers. [0003] The thermal stability of the electrolyte system and the non-flammability of the electrolyte solvent are the main factors affecting the safety of the battery. It can be seen that to improve the safety of batteries, developing a high-safety electrolyte system is the most effective measure. For example, the onset of battery thermal runaway is due to...

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Problems solved by technology

[0008] The actual technical problem to be solved in the present invention is to overcome the poor thermal stability of the electrolyte in which carbonate is the solvent in the prior art, the SEI film is easy to decompose, and there will be a reaction between the electrode and the electrolyte, and adding a large amount of flame retardants leads to The problem of electrochemical performance decline provides a sodium ion electrolyte, a secondary battery and its preparation method and application

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