Prelithiation of electrodes is a new process step to avoid the nearly 20% lithium loss during the SEI formation. A thin lithium layer is applied to the electrode surface as a sacrificial top coating using a physical vapor deposition process. This lithium layer is designed to reduce the lithium loss in the first formation cycle of the SEI. In order to establish this new process step in existing production chains, a connection must be made to the subsequent process step – the separation of the electrodes.
Due to the fact that lithium has a strong adhesive character, a conventional separation process- such as a punching process – is not suitable. Laser cutting is a contactless process and thus suitable for lithium application. Nevertheless, the energy input of the laser leads to a heat influence on the electrode. This energy input could cause the applied lithium layer to react with the gas components of the ambient atmosphere or be directly ablated, thus losing the added value of the prelithiation.
In this research, the influence of the laser cutting on prelithiated electrodes is investigated. Graphite-Silicon anodes are coated with different lithium layer thicknesses and then cut afterwards by a ND:YAG laser under the variation of laser parameters in terms of frequency and cutting velocity. These electrodes are examined with regard to their cutting edge quality. Finally, the influences of the cutting edges with respect to electrochemical performance are investigated.