Safe low-concentration electrolyte for lithium battery and application of safe low-concentration electrolyte

Abstract

The invention discloses a safe low-concentration electrolyte for a lithium battery and application of the safe low-concentration electrolyte, and belongs to the field of secondary batteries. The electrolyte contains lithium salt, a solvent for dissolving the lithium salt and a non-solvated cosolvent, the lithium salt is a mixed lithium salt rich in fluorine element, the overall concentration of the lithium salt does not exceed 0.6 mol / L, the solvent is a single solvent or a mixed solvent, the cosolvent is a fluorinated solvent, and the electrolyte has a flame-retardant effect. The problem that in the prior art, a low-concentration electrolyte cannot give consideration to high performance and high safety at the same time is solved, the low-concentration electrolyte capable of enabling a lithium battery to stably circulate and be safe is achieved by reasonably designing the components of the lithium salt, the solvent and the cosolvent, and compared with a traditional electrolyte, the electrolyte has the advantages that the lithium salt concentration is lower, the cost of the electrolyte can be remarkably reduced, and the electrolyte for the lithium battery, which is low in cost, high in performance and high in safety, is finally obtained.

Description

technical field [0001] The invention relates to the technical field of secondary batteries, in particular to a safe low-concentration electrolyte for lithium batteries and its application. Background technique [0002] Metal lithium has the highest theoretical specific capacity (3860mAh / g) and the lowest redox potential (-3.04V vs. standard hydrogen electrode), so lithium metal batteries that directly use metal lithium as the negative electrode are regarded as the next generation of high energy density batteries. However, the large-scale application of lithium metal batteries is facing severe challenges. On the one hand, the uneven deposition and unstable interface of the lithium anode during cycling will lead to a rapid decline in the capacity of the anode and potential safety issues. On the other hand, the structure of the cathode The destruction of the active material will lead to the loss of active material and the failure of the battery. [0003] The electrolyte is in ...

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Problems solved by technology

[0007] The purpose of the present invention is to overcome the problem that the low-concentration electrolyte in the prior art cannot take into account high performance and high safety. It intends to provide a safe low-concentration electrolyte for lithium batteries and its application. The idea is to adjust the solvation structure, interface structure and physical and chemical properties of the electrolyte at the same time. The present invention achieves a low-concentration electrolyte that can make the lithium battery stable and safe by rationally designing the composition of lithium salts, solvents and co-solvents. Compared with the traditional electrolyte, the electrolyte has a lower lithium salt concentration, which can significantly reduce the cost of the electrolyte, and finally obtain a low-cost, high-performance, high-safety electrolyte for lithium batteries

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