Influence of Tin (Sn) Dispersion on the Synthesis of Silicon Nanowires on Graphite Substrates for Li-Ion Batteries Anodes

Abstract

In recent years, because of a more prominent power electrification, lithium-ion batteries (LIBs) have attracted more and more interest in the scientific community. The desire to increase the battery performance, capacity, and power density has led to the development of new electrode materials. Silicon has emerged as a prominent anode material for next-generation lithium-ion batteries because of its high capacity [1] (10 times higher than graphite) and energy density. However, its utilization is limited by poor electronic conductivity and significant volume changes (up to 400%) observed during the lithiation-delithiation alloying process [1]. To address these challenges and promote wider adoption of silicon as an anode material, several strategies are being explored. Among these, one of the most promising approaches involves the use of silicon in nanowire form (SiNWs) [2,3] . SiNWs help to mitigate the volume expansion during cycling due to their nanostructure, hence giving higher capacity retention to the anode. In this study, SiNWs were directly grown on graphite flakes using tin (Sn) metal as seed through a straightforward and scalable synthesis method previously developed in our lab. This poster focused on the aim of achieving good homogeneity and dispersion of all the materials in order to optimize the SiNWs synthesis. To achieve this goal, an in-depth study has been performed on ball-mill mixing, investigating different milling times and speeds, and revealing the significant influence of these parameters on the final product. A comparative analysis between the ball-milled samples and those mixed using standard agitators demonstrates a reduced tendency for the formation of tin clusters in the ball-milled sample. Consequently, the ball-milled samples exhibit higher homogeneity in the distribution of the nanowires. These results have been confirmed by electrochemical tests performed in half-cells, that show the comparison of the performances for SNWs growth with different parameters.