Preparation method of lithium ion battery solid electrolyte interphase, and lithium ion battery

Abstract

Disclosed is a preparation method of a lithium ion battery solid electrolyte interphase. The preparation method comprises the following steps of 1, preparation of negative electrode uniform paste: weighing graphite, a conductive agent and a binder based on a certain mass ratio, then adding deionized water, and performing dispersion on the negative electrode uniform paste by a mechanical stirring disperser; 2, preparation of an organic solution electroplating tank: weighing a lithium salt, an organic solvent and an additive based on a certain mass ratio, and preparing an organic solvent electrolytic tank; 3, performing screening on the negative electrode uniform paste obtained in the step 1 and the coating the surface of a current collector copper foil with the screened negative electrode uniform paste, and then performing drying to prepare a primary negative electrode plate; and 4, enabling the primary negative electrode plate obtained in the step 3 to be immersed into the organic solution electroplating tank obtained in the step 2, and electroplating the primary negative electrode plate with a layer of organic film at a low current, and finally taking out and performing drying. The invention also provides the lithium ion battery, wherein the lithium ion battery is prepared by the working procedures of rolling, plate making, assembling, electrolyte injecting and sealing on thenegative electrode plate of the solid electrolyte interphase prepared by the steps 1-4, and a diaphragm, a positive electrode plate and an electrolyte.

Description

【Technical field】 [0001] The invention relates to the technical field of batteries, in particular to a preparation method of a lithium-ion battery solid electrolyte membrane and the lithium-ion battery. 【Background technique】 [0002] Formation is an important process in the production process of lithium-ion batteries. The so-called formation is the process in which the electrolyte and the electrolyte react on the negative electrode of the battery to form a solid electrolyte (Solid electrolyte interphase, SEI) film. The SEI film is an electronic insulator, but it is an excellent conductor of lithium ions. A uniform and stable SEI film can exist stably in the organic electrolyte, which can prevent solvent molecules from directly contacting the electrode material, thereby avoiding the co-intercalation of solvent molecules. The damage caused to electrode materials, thus forming a uniform and stable SEI film plays a crucial role in various electrochemical performances (such as c...

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Problems solved by technology

[0003] However, in the traditional chemical formation process, the formation of the SEI film consumes part of the lithium ions, which increases the irreversible capacity of the first charge and discharge, reduces the first charge and discharge efficiency of the electrode material, the utilization rate of the positive and negative electrode materials is low, and the battery manufacturing cost increases accordingly; At the same time, during this process, the electrolyte and the electrolyte react to produce ethylene, diethylene, phosphorus fluoride, hydrogen fluoride, carbon dioxide, carbon monoxide and other gases. The accumulation of these gases inside the lithium-ion battery will cause the pouch battery to bulge, deform or steel shell The battery is disconnected and turned on, which has a negative impact on the performance of the lithium-ion battery

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