COINAGE METAL-SILICON COMPOSITE FOR LITHIUM ION BATTERY

Today, a great deal of attention is concentrated on silicon (Si) as future anode material for Li-ion batteries, mainly due to its highest known theoretical capacity. However, Si-based anodes face significant challenges such as large volume expansion upon lithium insertion, which can result in electrode fracture and loss of electrical contact. Therefore, free standing silicon as an anode material is still insufficient for the practical use in Li-ion batteries. One of the recently explored routes toward overcoming these issues is Si based nanostructured composites.¹ Furthermore, in order to better understand the mechanisms of the Silicon anode evolution upon lithium intercalation during battery cycling, real time measurements are required.

Surface-enhanced Raman spectroscopy (SERS) is a technique that enhances Raman scattering by moleculs adsorbed on rough metal surfaces or by nanostructures, allowing the detection of single molecules. Moreover, coinage metals (Cu, Ag, and Au) are known to be Raman active and allow the SERS effect to take place.²

In this research, several coinage metals decorated silicon composites are prepared by a galvanic displacement reaction. We have found that the as prepared materials are electrochemically active and can be suitable to perform as anodes in Li-ion batteries. Moreover, the incorporation of coinage metals grants silicon surface optical properties. Consequently, by using a specially designed Raman cell,³ it is possible to follow the processes in silicon- coinage metal based battery trough an in situ surface enhanced Raman measurements.

1. Y. Miroshnikov, G. Grinbom, G. Gershinsky, G. D. Nessim, and D. Zitoun, Faraday Discuss., 2014, 173, 391–402.
2. S. Schlücker, Angew. Chemie - Int. Ed., 2014, 53, 4756–4795.
3. J. Yang, A. Kraytsberg, and Y. Ein-Eli, J. Power Sources, 2015, 282, 294–298.