Composite solid electrolyte and preparation method thereof

Abstract

The present invention discloses a composite solid electrolyte and a preparation method thereof. The composite solid electrolyte comprises an inorganic solid electrolyte and a polymer electrolyte. Theinorganic solid electrolyte is of a porous structure; the porosity of the inorganic solid electrolyte is less than 30%; and the inside of the inorganic solid electrolyte is provided with a continuouslithium ion channel composed of particles communicating with each other. The polymer electrolyte is arranged between the inorganic solid electrolytes for filling gaps, and account for less than 30% ofthe composite solid electrolyte. The porous inorganic solid electrolyte of the invention constitutes a main frame structure, which has a porosity below 30% and is the main bearer of lithium ion transportation. The polymer electrolyte is a gap filling material, which is mainly used for improving the overall flexibility of the composite solid electrolyte and reducing the impedance of the solid-solid contact interface between the positive electrode plate and negative electrode plate.

Description

technical field [0001] The invention belongs to the technical field of new energy, and in particular relates to a composite solid electrolyte and a preparation method thereof. Background technique [0002] The use of solid electrolytes instead of liquid organic electrolytes to assemble solid-state lithium batteries is expected to essentially solve the safety problems of existing liquid lithium-ion batteries. At the same time, the solid-state electrolyte has a wider operating voltage window and better chemical compatibility with the electrode. After using the solid-state electrolyte, the lithium battery can use a positive electrode material with a higher operating voltage, and the negative electrode can directly use metal lithium. Therefore, the energy density of solid-state lithium batteries may reach 2 to 5 times that of existing lithium-ion batteries, and the cycle and service life are longer, making them a candidate technology for next-generation battery energy storage wi...

AI Technical Summary

Problems solved by technology

However, after replacing the organic electrolyte with an inorganic solid electrolyte, the solid-liquid interface of the electrode material / electrolyte in the lithium battery system is also replaced by the solid-solid interface of the electrode material / solid electrolyte, and the wettability between the solid-solid interface is extremely low. Poor, resulting in high interface impedance

Although solid-state electrolytes composed solely of inorganic substances have high mechanical strength, their flexibility is poor, which means that solid-state batteries are prone to damage and fracture when subjected to deformation such as bending, and even lead to safety accidents.

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