Method for large-area representation of graphite/silicon/amorphous carbon composite structure silicon-carbon cathode powder body

Abstract

The invention discloses a method for large-area representation of a graphite / silicon / amorphous carbon composite structure silicon-carbon cathode powder body. The method comprises the following steps: placing the graphite / silicon / amorphous carbon composite structure silicon-carbon cathode powder body in the middle of a glass sheet with two flat surfaces, and compacting and flattening the powder body; testing the powder body with a laser Raman spectrometer, adjusting the peak of an obtained common Raman single spectrum to appear at positions near to 520 cm<-1>, 1,350 cm<-1> and 1,590 cm<-1>, and obtaining a test condition; obtaining a Raman imaging spectrum according to the test condition; respectively forming Raman imaged pictures for the intensities of a silicon peak, a carbon D peak and a carbon G peak, respectively imaging a ratio of the carbon D peak to the carbon G peak and a ratio of the carbon G peak to the carbon D peak, and judging whether the components and the structures in the powder body are consistent. The representation method disclosed by the invention is simple and quick, and can realize large-area representation of the distribution of silicon-carbon cathode components and research the structure consistency, so that the method has extremely high application prospect.

Description

technical field [0001] The invention relates to a method for characterizing negative electrode powders of lithium ion batteries, in particular to a method for characterizing graphite / silicon / amorphous carbon composite structure silicon-carbon negative electrode powders in a large area. Background technique [0002] Due to its high theoretical lithium storage capacity (4200mAh / g), silicon-based anode materials have aroused the research enthusiasm of many scientists. However, due to the huge volume change of the silicon-based material during the charge and discharge process, the electrode material of the battery will be cracked, pulverized, and structurally collapsed during the cycle. Therefore, the silicon material is mainly compounded with graphite (graphite sheet, spherical graphite, etc.), and then coated with a layer of amorphous carbon to prepare a silicon carbon material with a composite structure of graphite / silicon / amorphous carbon, which is used as the negative ele...

AI Technical Summary

Problems solved by technology

However, these methods generally have the problem of single characterization and the inability to simultaneously characterize the powder components and structure in a large area.

For example, XRD can analyze the silicon-carbon composition in the negative electrode powder, but it cannot give the distribution of the silicon-carbon composition; scanning electron microscopy can analyze the surface morphology of the powder particles, but it cannot give a large area of ​​the silicon-carbon composition. Partition distribution and its structural information; transmission electron microscopy can characterize the internal structure and component distribution of small particles, but it cannot simultaneously characterize the component distribution and structural consistency of silicon-carbon anodes in a large area; elemental imaging based on X-ray spectroscopy (EDX) Analytical methods can give the elemental distribution of silicon-carbon anodes, but it is time-consuming to use this method to characterize large-area silicon-carbon anode materials

In addition, both amorphous carbon and graphite are carbon-based materials, and the elemental analysis imaging method cannot distinguish the distribution of the two materials

Images