A kind of liquid leakage self-repairing lithium metal battery electrolyte and preparation method and application thereof

Abstract

The invention relates to an electrolyte solution for a leaking self-repairing lithium metal battery, including an organic solvent and a lithium salt. The organic solvent includes a first solvent and a second solvent, and the first solvent is selected from carbonate solvents, ether solvents, and carboxylates solvent, one or two of sulfone solvent and nitrile solvent, and the second solvent is cyanoacrylate solvent. In the present invention, by mixing cyanoacrylate solvent with common liquid electrolyte and lithium salt, when the battery is damaged, the electrolyte exposed to the air at the damaged part can undergo rapid polymerization, stop the continuous occurrence of leakage, and prevent liquid electrolysis The continuous oxidation and volatilization of the liquid; it can not only maintain high ionic conductivity and affinity to the electrode, but also improve the safety of the battery and prevent the continuous leakage of the electrolyte; it helps to form a uniform and stable SEI on the surface of lithium metal, Promote the uniform deposition of lithium, effectively inhibit the growth of dendrites, and increase the actual cycle life of the battery; the preparation method is simple, the performance is excellent, and the cycle performance of the battery is effectively improved.

Description

technical field [0001] The invention belongs to the field of lithium-ion batteries, and in particular relates to an electrolyte of a leakage self-repairing lithium metal battery and a preparation method and application thereof. Background technique [0002] The invention and use of lithium-ion batteries have promoted rapid progress in all aspects of modern society and brought great convenience to people's daily life. However, with the rise of new technology industries such as electric vehicles and drones, higher energy density requirements have been put forward for lithium-ion batteries. The use of lithium metal instead of traditional negative electrode materials (such as graphite materials, silicon materials, etc.) can greatly increase the energy density of the battery, and can increase the energy density of existing lithium-ion batteries by 5 to 10 times, so lithium metal batteries have attracted a wide range of applications. focus on. However, the nature of metallic lit...

AI Technical Summary

Problems solved by technology

However, the nature of metal lithium is extremely active, and the traditional liquid electrolyte will have at least the following problems in lithium metal batteries: (1) The battery is always in danger of potential leakage

Poor sealing effect, battery aging, overcharging, internal pressure rise, physical damage, etc. may cause leakage of liquid electrolyte in the battery; once leakage occurs, the electrolyte will quickly volatilize or oxidize, and the battery capacity will rapidly decay and cause battery failure

(2) The ion transport in the liquid state is uneven, and the electric field distribution is chaotic, which can easily lead to the growth of dendrites, lead to short circuit of the battery, and cause fire, combustion and explosion hazards

(3) The parasitic reaction between the extremely active Li metal and the liquid electrolyte produces an unstable and inhomogeneous solid electrolyte interfacial film (SEI), leading to irreversible consumption of Li metal and electrolyte

(4) The flammability of organic liquid electrolytes induces potential safety hazards, such as frequent electric vehicle fire incidents, which have aroused widespread concern from all walks of life

However, the ionic conductivity of solid electrolytes is generally low, which cannot meet the normal cycle of lithium metal batteries at room temperature, and the contact between solid electrolytes and electrodes is not good, and the interface impedance is large, which seriously affects the cycle capacity and cycle life of batteries.

At the same time, the difficulty of electron / ion transfer inside the electrode also makes it difficult for the electrode active material to achieve high load, and it is difficult to increase the energy density of the battery to a large extent.

In addition, the difficulty of processing and the high cost are also serious limitations of the solid electrolyte itself.

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