Polyether sulfur ether-based polymer electrolyte and preparation method thereof

Abstract

The invention discloses a polyether sulfur ether-based polymer electrolyte and a preparation method thereof. Bi-sulfydryl-containing 1, 2-dithioglycol, a diene-structure-containing diethylene glycol divinyl ether, and a tetra-sulfydryl-containing cross-linking agent tetra(3-mercaptopropionic acid) pentaerythritol are adopted, and a lithium salt, a photoinitiator and a plasticizer are added to perform an alkene-mercapto click chemistry reaction to prepare the polyether sulfur ether-based polymer electrolyte with the cross-linked network structure through a one-step method. The obtained polymerelectrolyte is high in mechanical property, high in ionic conductivity and stable in electrochemical window; and a lithium ion battery assembled by using the polymer electrolyte has the characteristics of being high in safety performance and stable in circulation.

Description

technical field [0001] The invention belongs to the field of lithium-ion battery electrolyte materials, and relates to a polyether sulfide-based polymer electrolyte and a preparation method thereof. Background technique [0002] Lithium-ion batteries are widely used in electronic products, mobile devices, electric vehicles and other fields due to their advantages such as high specific energy density, high working voltage, low self-discharge rate, long life, and no memory effect. At present, lithium-ion batteries mainly use liquid electrolyte systems, but their thermal stability is not good, and they are prone to safety hazards such as liquid leakage and short circuits caused by heat shrinkage of the diaphragm. The use of polymer electrolytes instead of liquid electrolytes not only overcomes the problem of poor safety of liquid electrolytes, but also effectively inhibits the growth of lithium dendrites in the negative electrode, and is easy to process and shape, which provide...

AI Technical Summary

Problems solved by technology

Polymer electrolytes mainly include polyethylene oxide (PEO), polyacrylonitrile (PAN), polymethyl methacrylate (PMMA) and polyvinylidene fluoride (PVDF) according to different substrates, among which polyethylene oxide ( PEO) is currently the most suitable matrix material for the preparation of polymer electrolytes. Its advantage is that it can form a stable complex with lithium salts, and realize the migration of Li+ by means of the movement of PEO chain segments, but it is easy to crystallize, which makes the ion conductivity at room temperature relatively low. low (at 10 -6 S / cm below), and the mechanical properties are not good

However, the modification (blending, copolymerization, grafting, crosslinking) and compounding of PEO failed to solve the problems of low room temperature ion conductivity and poor mechanical properties at the same time.

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