Lithium sheet for reducing interfacial impedance of solid electrolyte/lithium negative electrode, preparation method and application

Abstract

The invention discloses a preparation method of a lithium sheet that reduces the interface impedance of a solid electrolyte / lithium negative electrode, comprising the following steps: S1, weighing a small molecule solid solvent and a lithium salt respectively, for use; wherein, the small molecule solid solvent and the lithium salt The mass ratio is 70‑95:5‑30; S2, dissolve the small molecule solid solvent weighed in S1 in an organic solvent, stir at room temperature for 24 hours to obtain a mixed solution, and then add the lithium salt weighed in S1 to mix Dissolve in the solution to obtain a small molecule electrolyte solution; S3, apply the small molecule electrolyte solution obtained in S2 to the surface of the lithium sheet, and then dry it in vacuum at a certain temperature to obtain the described method for reducing the interface impedance of the solid electrolyte / lithium negative electrode. Lithium flakes. The invention also discloses the application of the lithium sheet to an all-solid lithium battery. During the charging and discharging process of the all-solid lithium battery, the lithium sheet can reduce the interface impedance between the solid electrolyte and the lithium sheet and improve the cycle performance of the battery.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a lithium sheet for reducing the interfacial impedance of a solid electrolyte / lithium negative electrode, a preparation method and an application thereof. Background technique [0002] As a material with high specific capacity (3861mAh / g) and low electrode potential (-3.04V vs SHE), lithium metal can significantly improve the energy density of the battery as the negative electrode material of the battery. The growth of dendrites can pierce the separator and cause a short circuit in the battery, which poses a safety hazard. The excellent mechanical properties of solid-state electrolytes can protect batteries from lithium dendrite puncture, which provides the possibility for the application of lithium metal in solid-state batteries. However, during the charging and discharging process of all-solid-state lithium batteries, the physical solid-solid contact ...

AI Technical Summary

Problems solved by technology

Commonly used methods include electrolyte surface modification, metal lithium surface modification, and adding polymer films. For example, by introducing a polymer buffer layer to construct a double-layer electrolyte structure, constructing Li y -M (M=Sn, Si, Ge) alloy negative electrode, or deposit a functional layer on the surface of the electrolyte by PECVD, magnetron sputtering, ALD and other techniques to reduce the interface impedance between the inorganic solid electrolyte and the lithium metal negative electrode, however These modification methods or operating conditions are demanding, or will affect the energy density of the battery

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