Introduction

Lithium Ion Battery

Separator – Orientation Distribution Analysis of Polypropylene

In general, polyolefin porous material such as polyethylene and polypropylene is used for the separator of  lithium ion battery. IR spectroscopy is widely used for evaluation of such materials in molecular size level.

Here the molecular orientation distribution of stretched polypropylene was evaluated by transmission method using the IRT-7000 IR Imaging System with optional polarizer. Ratio of peak at 809 cm^-1 due to vertical vibration to  peak at 1304 cm^-1 due to horizontal vibration is utilized to show the orientation distribution in imaging profiles. By polarization imaging method using the IRT-7000, the orientation distribution of sample can be seen clearly.

FTIR Imaging Microscopy

Cathode Evaluation

Transition metal oxide such as LiCoO₂ is used as material for cathode electrode.  Raman spectroscopy is an effective method for analysis of material deterioration.

Anode Evaluation

Raman spectrum of carbon nanotube depends on excitation wavelength due to its diameter and helicity. It is possible to measure carbon nanotubes with different diameters selectively by changing excitation wavelength and to evaluate crystallinity by D-band.

JASCO NRS-5000/7000 series with multi laser mounting capability can provide optimum method for carbon nanotube evaluation.

Raman Spectroscopy for Carbon Nanotube (CNT) with Different Excitation

Raman Imaging Microscopy

Binder Evaluation

PVDF (polyvinylidene difluoride) is one of the materials used for binder of lithium ion battery. The material quality and distribution condition of the binder are closely related to lifetime and performance of battery.

Raman imaging can analyze the distribution condition of both active materials and binder.

Chirality Analysis of Carbon Nanotube

JASCO NIR Spectrofluorometer is the upgraded system based on FP-8600 with NIR Photomultiplier tube, which has wider measurement range up to 1700 nm.

This system can measure fluorescence spectra of materials which have fluorescence in NIR region such as rare earth materials and Carbon nanotube. The evaluation method by 3D fluorescence spectrum measurement using of excitation / fluorescence wavelength scanning function is very useful especially for carbon nanotube sample since its characteristics depends very much on tube diameter and chiral angle.

NIR Spectrofluorometer