In Situ, Time-Resolved Raman Spectromicrotopography of an Operating Lithium-Ion Battery

A Raman microscope has been coupled to a sealed optical chamber mounted on a two-dimensional linear translator to allow in situ acquisition of space-, and time-resolved spectra from a sharply defined edge of thin operating graphite/LiCoO₂ Li-ion battery exposing the anode (A), separator (S), and cathode (C), during charge and discharge along an axis normal to the layered A!S!C plane. Clear evidence was obtained for changes in the amount of Li⁺ within particles of graphite, and, to a lesser extent, of LiCoO₂, during battery discharge both as a function of position and time. Such time-resolved Raman spectromicrotopography measurements can provide means of assessing the validity of theoretical models aimed at simulating the flow of Li⁺ within Li⁺-batteries under operating conditions.