Three-dimensional imaging method for realizing dendritic crystals in lithium metal battery by using photoacoustic imaging

Abstract

The invention discloses a three-dimensional imaging method for realizing dendritic crystals in a lithium metal battery by using photoacoustic imaging. Sample preparation comprises: cutting out a portion having a flat cross section on a symmetric battery sample, wherein the side surface of the portion is a photoacoustic imaging observation surface; cutting off one corner of a cathode lithium sheetfor marking a relative position of the sample; placing the portion into a stainless steel button battery shell for electrochemical test, and performing charging test by using set current intensity; and after charging is completed, disassembling a button battery, and taking out the battery sample to complete the sample preparation. Image acquisition comprises: putting the sample on a sample platform, and fixing the sample; ensuring that the sample is located on a focal plane of laser by adjusting the height of the sample and observing the intensity of an ultrasonic signal; and performing two-dimensional scanning on the sample. The three-dimensional imaging method disclosed by the invention realizes three-dimensional imaging of the dendritic crystals in the lithium metal battery by using thephotoacoustic imaging, so that the method has an extremely large penetrating depth; metal features can also be directly observed even in a membrane; and the three-dimensional imaging method has the advantages of relatively low cost and easy operation.

Description

technical field [0001] The invention relates to the technical field of dendrite imaging in metal batteries, in particular to a three-dimensional imaging method for realizing dendrites in lithium metal batteries by using photoacoustic imaging. Background technique [0002] A quantitative understanding of Li metal dendrite growth in both conventional liquid electrolytes and current solid-state electrolytes, and the exploration of conditions that can achieve smooth Li deposition with a thickness of tens of micrometers are extremely important. Imaging techniques have proven to be powerful tools for studying dendrite growth. For example, scanning and transmission electron microscopy have been widely used to acquire images of lithium dendrites with high resolution and high quality. Although electron microscopy has the potential to provide insight into dendrite formation, its sample preparation requirements are very demanding. Therefore, it is very challenging for in situ observa...

AI Technical Summary

Problems solved by technology

[0004] i), unable to realize three-dimensional imaging; ii), low spatial resolution, not reaching the micron level; iii), unable to observe the dendrite growth in the diaphragm; iv), unable to observe the microstructure of "bulk lithium dendrite"; v), Very demanding sample preparation requirements, making it unsuitable for in situ observation; vi), slow imaging speed and low temporal resolution

Specifically: a), the disadvantages of the electron microscope are iv and v; b), the disadvantages of the X-ray tomography scanner are iv and vi; c), the disadvantages of the magnetic resonance imaging are ii; d), the disadvantages of the optical microscope are i

Furthermore, all these 4 techniques have disadvantages iii

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