Preparation method of in-situ polymerized solid electrolyte

Abstract

The invention relates to the field of polymer materials, and discloses a preparation method of an in-situ polymerized solid electrolyte, which aims at the problems of shuttle effect and loss of activesubstances caused by diffusion of discharge products in the prior art. The preparation method comprises the following steps: (1) dissolving lithium bis(trifluoromethanesulfonyl)imide into a mixed solution of ethylene glycol dimethyl ether and 1,3-dioxolane; (2) dissolving pentaerythritol tetraacrylate and 2-hydroxyethyl acrylate in the electrolyte, adding azodiisobutyronitrile, and uniformly stirring the electrolyte at room temperature; and (3) assembling the polymer slurry, a sulfur positive electrode and a lithium negative electrode into a button battery, and heating the button battery to cure the polymer slurry in situ in the battery to obtain a finished product. According to the present invention, the polysulfide shuttle effect in the lithium-sulfur battery is effectively reduced, theinterface problem of the negative electrode lithium dendrites and the battery is significantly improved, and the hydroxyl-containing polymer structure unit is introduced to prepare the in-situ polymerization type multi-block polymer electrolyte, such that the solid polymer lithium-sulfur battery has excellent electrochemical performance.

Description

technical field [0001] The invention relates to the field of polymer materials, in particular to a method for preparing an in-situ polymerized solid electrolyte. Background technique [0002] Currently, lithium-sulfur batteries using liquid electrolytes and lithium anodes are favored due to their high energy density. The lithium-sulfur battery with elemental sulfur as the positive electrode and metal lithium as the negative electrode has a high specific energy density (2600 Wh kg-1), and has become the focus of research in the field of secondary batteries today. In addition, the sulfur cathode also has the characteristics of low price, abundant resources, and environmental protection, making lithium-sulfur batteries one of the most promising high-energy-density secondary batteries. However, there are still various problems in lithium-sulfur batteries at present: the sulfur positive electrode and the discharge product (Li 2 S and Li 2 S 2 ) Low electron and ion conduction...

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Problems solved by technology

[0005] The present invention aims to overcome the shuttle effect and the loss of active materials caused by the easy diffusion of discharge products in the prior art, and provides a method for preparing an in-situ polymerized solid electrolyte, which significantly improves the polysulfide shuttle effect in lithium-sulfur batteries , the interface problem between negative electrode lithium dendrite and battery, from the perspective of molecular microstructure, design the structure of functional groups and chain segments of polymers, introduce hydroxyl-containing polymer structural units, and prepare in-situ polymerized multi-block polymer electrolytes ;Through the determination of the kinetic parameters and battery cycle performance parameters of the lithium-sulfur battery, the interface characteristics of the electrode and the polymer electrolyte can be adjusted in a targeted manner, so that the solid-state polymer lithium-sulfur battery has excellent electrochemical performance

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