Observation of Component Distribution in Lithium-Ion Battery
Raman Imaging of positive electrode in lithium-ion secondary battery
Only 20 minutes shows the imaging of component distribution on the surface of electrode
The image above shows an imaging of positive electrode in lithium-ion secondary battery by Raman microscope. Active material-lithium cobalt oxide (LiCoO2) and electric conduction addition agent-carbon (acetylene black) are shown in red and blue respectively. Only 20 minutes can do the Raman imaging of component distribution over a wide range with the high spatial resolution of 350nm.
About the sample used for measurement
Mix N-CH3pyrrolidone with lithium cobalt oxide, acetylene black and PVDF, and spread them on both sides of Aluminum foils until dry.
Observation of component distribution on the surface of positive electrode
The graph below shows the averaged Raman spectra in the selected rectangular regions (red frame, blue frame in the bottom-right image). In the spectrum of red frame, two peaks of lithium cobalt oxide (485cm-1,597cm-1) can be seen. Besides, in the spectrum of blue frame, two peaks of carbon (1350cm-1, 1590cm-1) also can be seen.
Averaged Raman spectra in the selected rectangular regions (red frame, blue frame in the top-right image)
Observation of component distribution on the surface of deteriorated positive electrode
Raman imaging of deteriorated positive electrode in a lithium-ion battery after laser irradiation
The image above shows the Raman imaging of deteriorated positive electrode in a lithium-ion battery after laser irradiation. As a result, we can find out cobalt oxide (green) in addition to lithium cobalt oxide (red) and acetylene black (blue).
The graphs below show the averaged Raman spectra in the selected rectangular regions (red frame, blue frame and green frame in the bottom-right image). As a result of electrode damage, we can find that new components which have some peaks of low wavenumber region in the green frame were produced. When we enlarge the Raman spectra of low wavenumber region, we can see there’re peaks of cobalt oxide (482,522,691cm-1) in the spectra of green frame.
(upper)Averaged Raman spectra in the selected rectangular regions (red frame, blue frame and green frame)
(below)Enlarged averaged Raman spectra(red frame and green frame) of low wavenumber region
An overlap of optical microscope image and Raman image
An overlap of optical microscope image and Raman image (From the left,the transparency of Raman image is 100%、75%、50%、0%)
In the Raman-11, it can show that the Raman image acquired from Raman measurement overlaps the optical microscope image. The transparency of Raman image can be freely adjusted by dragging the slider right or left on software.
In this way, Raman-11, only 20 minutes can do the imaging of element distribution of electrode material, analyzes secondary battery material and becomes a highly evaluated strong tool.
