Lithium ion battery and preparation method thereof

Abstract

The invention provides a lithium ion battery and a preparation method thereof. The lithium ion battery comprises a battery shell body and an electrical core located in the battery shell body; the electrical core includes a positive electrode, a negative electrode and an electrolyte located between the positive electrode and the negative electrode; the electrolyte is characterized in that the electrolyte comprises a first solid electrolyte layer located on the positive electrode surface and a second solid electrolyte layer located on the negative electrode surface, and the first solid electrolyte layer makes contact with the second solid electrolyte layer; the first solid electrolyte layer comprises a first binder and first inorganic electrolyte particles, the first inorganic electrolyte particles are an NASICON type inorganic electrolyte and / or a perovskite type inorganic electrolyte; the second solid electrolyte layer comprises a second binder and second inorganic electrolyte particles, and the second inorganic electrolyte particles are an sulfide based solid electrolyte. The lithium ion battery prepared by the method has the advantages of high safety, relatively high capacity and good cycle performance.

Description

technical field [0001] The invention belongs to the field of lithium ion batteries, in particular to a lithium ion battery and a preparation method thereof. Background technique [0002] Compared with other batteries, lithium-ion batteries have the advantages of light weight, small size, high working voltage, high energy density, high output power, high charging efficiency, no memory effect, long cycle life, etc., not only in mobile phones, notebook computers and other fields It has been widely used, and is also considered to be one of the best choices for electric vehicles and large-scale energy storage devices. At present, commercial lithium-ion batteries widely use liquid electrolytes; however, organic liquid electrolytes are volatile and flammable, resulting in Lithium-ion batteries have always had the risk of leakage, combustion, and explosion. Due to the volatility and flammability of organic liquid electrolytes, lithium-ion batteries with electrolyte systems cannot co...

AI Technical Summary

Problems solved by technology

At present, there is no such commercial product, and the high cost is also a major barrier to the further large-scale promotion and application of all-solid-state thin-film lithium batteries; the sulfide-based solids used in bulk-type all-solid-state lithium batteries The electrolyte also has problems such as high cost and poor process operability; more importantly, there is an interface effect between the sulfide-based solid electrolyte and the positive electrode material, which greatly affects the performance of the all-solid-state battery

Surface coating of positive electrode materials is one of the strategies to alleviate this problem. However, due to factors such as volume changes in the process of deintercalating lithium from electrode materials, the coating layer is often broken, so it still cannot solve the performance degradation of all-solid-state lithium batteries during cycling. The problem