Solid polymer electrolyte containing boron-fluorine structure as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of lithium ion batteries, and particularly relates to a solid polymer electrolyte containing a boron-fluorine structure as well as a preparation method andapplication of the solid polymer electrolyte. The preparation method of the solid polymer electrolyte comprises the following steps of S1, adding a vinyl boron-fluorine monomer, a vinyl polyether monomer, a modified monomer and a functional polymer into a solvent, adding an initiator for reaction, and performing purification treatment to obtain a polymer system B; S2, adding the polymer system B,a lithium salt, a filler and an auxiliary agent into the solvent, adding a cross-linking agent to obtain a mixed solution, uniformly coating a mold with the mixed solution, and then reacting; S3, obtaining the solid polymer electrolyte; assembling the obtained solid polymer electrolyte, a positive pole piece and a negative pole piece into a solid battery cell, then welding tabs, and carrying outheat treatment and packaging treatment to obtain the lithium ion battery. The solid polymer electrolyte containing the boron-fluorine structure has good high voltage resistance, high conductivity andlithium metal compatibility.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a solid polymer electrolyte containing a boron-fluorine structure and a preparation method and application thereof. Background technique [0002] Lithium-ion batteries have been widely used in digital, power and other energy storage fields. Lithium-ion batteries are mainly composed of positive electrode materials, negative electrode materials, electrolytes, diaphragms and other main materials. In the use of lithium-ion batteries, thermal runaway is prone to occur, which can lead to safety issues such as fire and explosion. As the most likely next-generation lithium-ion battery, solid-state batteries have the characteristics of high-quality energy density and high safety. Solid-state batteries are mainly composed of positive electrode materials, negative electrode materials and solid electrolytes, of which solid electrolytes mainly include sulfide electr...

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Problems solved by technology

Although sulfide electrolytes have high conductivity, they have problems such as poor processability and high cost; oxide electrolytes have problems such as poor interface contact and poor flexibility; polymer electrolytes are currently mainly represented by polyethylene oxide (PEO), although There are disadvantages such as low conductivity and high voltage resistance, but the electrochemical performance can be improved by improving the polymer structure

[0003] In order to improve the electrochemical performance of solid polymer electrolytes, the Chinese invention patent application with application number 201711049442.5 discloses a non-combustible polymer electrolyte. The polymer electrolyte is mainly composed of a polyether structure and a phosphate ester structure. The polymer electrolyte is due to the Contains a large amount of phosphorus-containing structure, which has non-combustible properties, but the introduction of an epoxy structure that is not resistant to high voltage will lead to partial oxidation and decomposition of the polymer electrolyte

The Chinese invention patent application with the application number 201810950307.6 discloses a composite high-voltage resistant solid polymer electrolyte prepared by polyethylene oxide, lithium salt and inorganic additives, wherein the inorganic additive is a boron-containing inorganic additive, but the composite solid-state polymer electrolyte prepared by the patent The boron-containing structure of the material electrolyte and the lithium-conducting polyether structure are simply physically mixed, and the lithium ion conductivity at room temperature is low, which will directly affect its performance.

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