Operando Micro-Raman Study Revealing Enhanced Connectivity of Plasmonic Metals Decorated Silicon Anodes for Lithium-Ion Batteries

The efficient formulation of silicon based, high-loading electrode with good capacity retention and cycling stability remains challenging. To gain a better understanding of the ongoing processes and failure mechanisms occurring during battery performance, operando micro-Raman spectroscopy is helpful to map the active silicon sites. Herein, we present the investigation of the electrochemical performance of anodes composed of plasmonic metal (Ag and Au) decorated silicon, designed for enhancing Raman signal. Following the discovery that only a partial amount of the electroactive material undergoes lithiation in the first cycle, we show that the plasmonic metal tips can enhance the connectivity of the Si particles. The micro-Raman mapping of electroactive silicon material reveals how the plasmonic metals influence the distribution of silicon active sites during battery cycling. The ratio of electroactive Si is found to increase from Si to Si/Au and Si/Ag electrodes, and the results are explained in terms of interconnectivity of the particles.