Cu catalized CVD of SiNWs for lithium-ion batteries

In the challenge to improve the charge capacity of lithium–ion batteries (LIBs), Si is considered a promising material to replace the conventional C-based anode, due to its highest known theoretical capacity 1 of 3800 mAhg-1 and a low delithiation potential, below 0.5 V against Li /Li+. However, its use has been hindered by the poor capacity retention upon cycling, due to electrode cracking and pulverization related to huge volume expansion (up to 400%) upon the repeated charge/discharge process. In order to overcome the volume change and enhance or maintain the electric contact between silicon and the electrode, nanostructured anodes have attracted particular attention. SiNWs offer direct one-dimensional electronic pathways for rapid charge transport and reduce stress relaxation, preventing material fragmentation. In this context, we have investigated the electrochemical performance of Si-NWs grown on carbon fibers (CP) by Cu-catalysed Chemical Vapour Deposition (CVD). In this work, we show the role of different SiNWs morphologies on the electrochemical performance of the cell. In particular, we have observed that the reduction of the SiNWs diameter improves strongly the stability of the cell and limits the capacity fading. This project is carried out within the framework "Ricerca di Sistema Elettrico" which is funded by the Italian Ministry of Economic Development (MISE).