A kind of composite solid electrolyte and its preparation method and application in solid secondary battery

Abstract

The invention discloses a conductive coated composite solid electrolyte, a preparation method thereof and an application in a solid secondary battery. The composite solid electrolyte of the present invention is composed of inorganic solid electrolyte particles and a polymer electrolyte coating layer formed on the surface thereof. The preparation method of the composite solid electrolyte includes: uniformly mixing the polymer / polymer monomer, cationic compound salt, and inorganic solid electrolyte powder in a certain proportion to obtain a precursor solution, and initiating the polymer monomer on the surface of the solid electrolyte particle by adding an initiator. In-situ polymerization, or adding a precipitating agent to precipitate the polymer on the surface of the solid electrolyte particles, thereby preparing a composite solid electrolyte. Further, the composite solid electrolyte prepared above is mixed with a solvent in a certain proportion to obtain a uniform and stable slurry, and a solid electrolyte film is prepared on the substrate or electrode surface by using a casting coating process for the production of solid secondary batteries.

Description

Technical field: [0001] The invention relates to a composite solid electrolyte, its preparation method and its application in solid secondary batteries. Background technique: [0002] At present, secondary batteries based on liquid organic electrolytes have safety problems such as dendrite growth, electrolyte leakage, and battery thermal runaway, which severely limit the application of secondary batteries in the field of long-cycle, high-safety energy storage. The use of solid electrolytes instead of organic electrolytes is expected to significantly improve the safety of secondary batteries under operating conditions. Solid electrolytes can be divided into two categories according to their chemical nature: polymer electrolytes and inorganic solid electrolytes (such as ceramic electrolytes, glass electrolytes, and glass-ceramic electrolytes, etc.). Polymer electrolytes have lower electrode / electrolyte interface resistance and wettability, lower cost and better processability...

AI Technical Summary

Problems solved by technology

However, the rigid interface formed between the electrolyte and the electrode material hinders the conduction of working ions

In order to obtain higher ionic conductivity, the electrolyte sheet usually requires high-temperature heat treatment to obtain higher density, which will increase the brittleness of the electrolyte sheet and make it difficult to process

Therefore, it is difficult for a single polymer electrolyte or inorganic solid electrolyte to meet the application requirements of secondary batteries.

[0003] Although there are currently studies that combine the advantages of organic and inorganic solid electrolytes, mixing and hybridizing the two to improve the overall performance of the solid electrolyte, the type, amount, and particle size of the inorganic solid electrolyte are all important to the performance of the composite solid electrolyte. The conductivity has a certain influence, and because the two only have a specific ion conduction enhancement phenomenon at the organic-inorganic composite interface, the conduction enhancement effect on lithium ions is limited.

At present, there is no research involving the selection, morphology, and structure of polymer solid electrolytes and inorganic solid electrolytes on the effect of improving conductivity.

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