An electrode structure for in situ observation of lithium ion diffusion process

Abstract

The invention relates to an electrode structure for in-situ observation of the diffusion mode of lithium ions in graphite materials. It uses a circular working electrode structure and a ring-shaped counter electrode structure to form an edge-to-edge structure in which the two electrodes are distributed according to the positions of concentric circles in the plane; the diffusion form of lithium ions in the electrodes is along the radial direction of the electrodes. The shape of the working electrode is circular, and the shape of the counter electrode is ring-shaped. The inner diameter of the ring electrode is larger than the outer diameter of the circular electrode; the conductive device is a copper metal pin with a flange, the upper part is pressed on the electrode material, and the lower part is connected The conductive copper ring is connected to realize the communication between the electrode material and the external wire. The invention can directly observe the diffusion process of lithium ions in the working electrode during the intercalation / delithiation cycle process, and overcomes the difficulty that the traditional electrode cannot be measured due to the face-to-face method. At the same time, the design of the circular electrode is more in line with commercial The structural design of the electrodes also enables the study of diffusion evolution in all directions.

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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