Development of In Situ Cross-Sectional Raman Imaging of LiCoO2 Cathode for Li-ion Battery

A novel in situ Raman imaging technique has been developed to visualize the Li-ion battery reaction during the charge/discharge operation. A specially designed cell enables to measure Raman spectra at high speed so that the in situ measurements are carried out during the reaction. The distribution of the state of charge in cross-section of LiCoO2 cathode has been visualized as a demonstration. Inhomogeneous state of charge distribution is observed and there are some active materials where Li+ does not completely return after discharging. This technique enables to evaluate not only the electrode performance but also battery degradation, and thus may promote the realization of the next generation batteries. (C) The Electrochemical Society of Japan, All rights reserved.