For years, Lithium-ion batteries have been of great interest as the rechargeable counterpart to traditional Lithium batteries. They are used in portable electronic devices and newly developed electric cars. Performance, however, is key to the ubiquitous use of this technology. Chiefly, this performance is influenced by many factors including the state of the cathode and anode. During the charge and discharge process, the lithium ions travel from one electrode to the other (through the electrolyte), which induces structural changes of both materials. While some of these observed changes are fully reversible in the cathode and anode, others are not.
Raman spectroscopy gives a direct answer about structural changes occurring in analyzed materials. Being contactless and fast, it does not influence the samples and, in the case of batteries, allows real-time analysis during the charge/discharge cycle.
In addition to Raman, we will briefly discuss a couple of other applicable spectroscopy techniques – GD-OES and XRF. Glow Discharge (GD-OES) technology provides information about elemental distribution/depth profile of the materials used in the Li-battery industry. Micro-XRF, as a non-destructive technique, allows one to inspect internal parts of batteries without disassembly. Several application examples will be presented in detail.