Lithium battery negative electrode and method for preparing the negative electrode by solid-state electrochemical corrosion method

Abstract

The invention relates to a lithium battery negative pole and a method for preparing the negative pole by a solid-state electrochemical corrosion method. The method includes: establishing a solid-state electrochemical corrosion system; the solid-state electrochemical corrosion system includes: an initial pole piece composed of three layers: an electrode active layer, a solid electrolyte layer and a lithium-containing metal layer; wherein the solid electrolyte layer is located The middle of the electrode active layer and the lithium-containing metal layer; the electrode active layer is in direct contact with a part of the lithium-containing metal layer to form an internal short circuit to form an electronic channel; the electrode active layer and the rest of the lithium-containing metal layer The regions are respectively in contact with the solid electrolyte layer to form ion channels; the initial pole piece is placed in an inert gas or vacuum environment, and the initial pole piece is electrochemically corroded, and the lithium-containing metal layer The electrode active layer is pre-lithiated to obtain a pre-lithiated lithium battery negative electrode sheet.

Description

technical field [0001] The invention relates to the field of material technology, in particular to a lithium battery negative electrode and a method for preparing the negative electrode by a solid-state electrochemical corrosion method. Background technique [0002] Traditional lithium-ion batteries usually use embedded reaction negative electrodes, such as graphite, silicon-carbon composite electrodes, etc., but these electrode materials will consume lithium ions due to the formation of a solid electrolyte interface (SEI) film during the first charge and discharge process, resulting in a large irreversible capacity. Loss, thereby restricting the energy density and cycle life of lithium-ion batteries. [0003] Lithium supplementation through the contact reaction between metal lithium and the negative electrode is the most simple and effective pre-lithiation method that has been proven so far. [0004] The common pre-lithiation method is to contact the metal lithium with the...

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Problems solved by technology

However, there are many side reactions between metal lithium and electrolyte in this method, which makes the utilization rate of metal lithium low, and the by-products will also increase the polarization of the negative electrode, which will affect the performance of the battery.

[0005] In addition, in the absence of an electrolyte, metal lithium and the negative electrode itself can react after direct contact, that is, pre-lithiation is carried out by chemically corroding metal lithium, but the surface of the electrode exists due to the adsorption of impurities in the environment. Oxygen-containing functional groups will react with lithium metal to form an oxide layer, hindering the full progress of the pre-lithiation reaction

Under such circumstances, metal lithium cannot be fully utilized, and the residual metal lithium after battery assembly will further undergo side reactions with the electrolyte, resulting in a large negative electrode polarization.

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