Electrode structure for in situ observation of lithium ion diffusion process

Abstract

The invention relates to an electrode structure for in situ observation of a lithium ion diffusion mode in a graphite material. A circular working electrode structure and an annular counter electrodestructure are used to form an edge-to-edge structure in which two electrodes are distributed in the in-plane concentric circle position. The lithium ion diffusion form in the electrodes is in the radial direction of the electrodes. The working electrode thereof is circular, and the counter electrode is annular. The inner diameter of the annular electrode is larger than the outer diameter of the circular electrode. A conductive device uses a copper metal pin with a flange. The upper part is pressed on the electrode material. The lower part is connected with a conductive copper ring to realize the communication between the electrode material and an external wire. According to the invention, the lithium ion diffusion process of the working electrode during an insertion / de-lithium cyclic process can be directly observed in situ; the difficulty of unable measurement caused by a conventional face-to-face electrode method is overcome; the design of the circular electrode is more in line withthe structural design of a commercial electrode; and diffusion evolution in all directions can be studied.

Description

technical field [0001] The invention belongs to the field of electrochemistry, and in particular relates to an electrode structure for in-situ observation of the diffusion mode of lithium ions in graphite materials. Background technique [0002] With the development of new energy technologies such as lithium-ion batteries, graphite electrode materials, which are typical representatives of commercial electrodes, are widely used in various electronic devices, electric vehicles and other fields. The back-and-forth migration of lithium ions will lead to alternate volume expansion and contraction of the electrode, which will generate corresponding strain / stress accumulation, resulting in capacity degradation and lifetime attenuation of graphite materials. Therefore, the diffusion process of lithium ions has a great influence on the mechanical-electrochemical performance of electrodes, and even relates to the development trend of lithium batteries in the future. For the inherent ...

AI Technical Summary

Problems solved by technology

At present, there are methods for in-situ observation of the electrode reaction of lithium-ion batteries. The electrode structure used is still a face-to-face up-and-down structure. The lithium ion diffusion method is actually along the normal direction of the working electrode, and the electrode structure is not strictly limited. The opposite side form, and the constraint form is relatively complicated, which is not very convenient for diffusion research[1]

There are other studies that design the working electrode as a square, and form an arrangement form with one side of the square working electrode and the counter electrode, but they only study the diffusion of the electrode along the one-dimensional direction [2], and the shape of the square working electrode There are also certain differences from the circular electrodes used in real life, which cannot more closely reflect the diffusion process of lithium ions.

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