High voltage-resistant multi-stage structure composite solid-state electrolyte for lithium battery

Abstract

The invention discloses a high voltage-resistant multi-stage structure composite solid-state electrolyte and its preparation method and use in a solid-state lithium battery. The lithium battery utilizes a multi-stage structure solid-state electrolyte containing different components. A polymer electrolyte with excellent electrode interface compatibility is used as an electrolyte in the negative electrode side. A high voltage-resistant polymer electrolyte is used as an electrolyte in the positive electrode side. A polymer electrolyte or an inorganic electrolyte with high ionic conductivity is used as a middle layer. The multi-stage structure solid-state electrolyte has advantages such as high mechanical properties, high ionic conductivity, a wide electrochemical window, excellent electrode interfacial compatibility and lithium dendrite growth inhibition of different components. Compared with the traditional liquid lithium ion battery, the battery with the multi-stage composite solid-state electrolyte has higher safety and higher energy density.

Description

technical field [0001] The invention relates to battery technology, in particular to a composite solid electrolyte with a multi-level structure and a preparation method thereof, as well as its application in lithium batteries. Background technique [0002] At present, large-scale commercial lithium-ion batteries generally use organic carbonate-based liquid electrolytes. There are dangers of leakage, burning, explosion and so on. Therefore, safety issues have become a key factor restricting the development of lithium-ion batteries. Replacing the original liquid electrolyte with a solid electrolyte can effectively improve the safety performance of lithium-ion batteries. Lithium-ion batteries using solid-state electrolytes have good safety performance, high energy density, and wide operating temperature, and have become one of the research hotspots. At the same time, the solid electrolyte has a high Young's modulus, which can inhibit the formation of lithium dendrites and re...

AI Technical Summary

Problems solved by technology

[0003] So far, most solid-state electrolytes use a single component as the electrolyte. Although it can improve the safety performance and energy density of lithium-ion batteries, there are often some disadvantages in a single electrolyte.

As one of the most widely studied electrolyte matrices, polyoxyethylene (PEO) matrix has low ionic conductivity, which is difficult to meet the requirements of lithium-ion batteries at room temperature.

201410378107.X and 200680012628.7 disclosed the preparation of PEO-containing electrolytes. Although the ionic conductivity has been improved, the electrochemical stability window of PEO decomposition voltage is lower than 4.2 V, which is difficult to match with high-voltage cathode materials.

201510078309.7 discloses a solid electrolyte with polypropylene carbonate (PPC) as the matrix, which has high ionic conductivity at room temperature, however, at low potential, PPC is easily decomposed into small molecules, which affects the performance of the battery

Inorganic solid electrolytes have high ionic conductivity, however, their preparation process and interfacial compatibility with electrodes inhibit their commercial application

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