Preparation method and application of succinonitrile-based double-layer composite polymer electrolyte

Abstract

The invention discloses a preparation method and application of a succinonitrile-based double-layer composite polymer electrolyte, succinonitrile has good ionic conductivity and high oxidation stability, and electrolyte taking succinonitrile as a matrix can keep good stability with a metal lithium negative electrode. And high lithium ion conductivity can be maintained at the interface of the electrode, so that the charge-discharge efficiency can be ensured. The ionic conductivity of the composite polymer electrolyte at room temperature can reach 4.27 * 10 <-4 > S cm <-1 >, the electrochemical window width is 0-5.1 V (relative to Li < + > / Li), no short circuit phenomenon exists after the assembled metal lithium symmetrical battery is circulated for more than 250 hours, and the good flexibility of the polymer can enable all interfaces in the battery to be in close contact, so that the interface resistance is reduced. The electrolyte with the double-layer structure is a promising solid-state battery candidate electrolyte, a high-voltage positive electrode and a low-voltage metal negative electrode can coexist in the battery by utilizing the double-layer structure, and the development and commercialization of the solid-state secondary battery can be greatly accelerated by the brand new solid-state electrolyte design.

Description

technical field [0001] The invention belongs to the technical field of solid electrolytes, and in particular relates to a method for preparing a succinonitrile-based double-layer composite polymer electrolyte and an application thereof. Background technique [0002] With the continuous development of science and technology and the market, people's demand for large-capacity, high-density and miniaturized batteries is increasing. Traditional lithium-ion battery electrode materials have been difficult to meet people's needs in the field of electric vehicles and digital products. Therefore, scientific researchers High specific energy battery materials are being actively explored. Due to its high energy density and high safety, solid-state batteries are very suitable to meet the rapidly growing demand for higher battery capacity and stricter safety performance. Therefore, solid-state batteries have become the focus of the next generation of batteries and have attracted much atten...

AI Technical Summary

Problems solved by technology

However, low ion conductivity at room temperature, low lithium ion transfer number and narrow electrochemical window severely limit its practical application. In order to solve the above shortcomings, people have adopted various additives to reduce the crystallinity of PEO. It is worth noting that What is interesting is that although the presence of the additive can improve the poor interfacial contact with the electrode, it also leads to poor mechanical strength and unstable compatibility with Li metal.

Therefore, although metal lithium solid-state batteries based on polymer electrolytes have the advantages of high energy density and high safety performance, the electrochemical window of the polymer electrolyte is narrow, and it is easy to be catalyzed by high-voltage positive electrodes and reduced by metal lithium negative electrodes. Reduce the energy density and cycle performance of the battery

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