Nanostructured Silicon on Stainless Steel as a Binder-free and Carbon-free Anode for Lithium-ion Batteries

The chemical vapor deposition method with an Au thin film as the catalyst and SiCl4 as the Si-containing precursors was used to fabricate nanostructured Si, including Si nanowires, on stainless-steel substrates. All samples synthesized at 750−1000 °C and 15−60 min showed Si deposition, with Si nanowires obtained at 1000 °C for the duration of 25−30 min. The nanostructured Si produced on the conductive stainless-steel substrates was used directly as a working electrode in a Li-ion battery (LIB) cell, enabling a simple binder-free and carbon-free cell assembly. The electrochemical performance of the nanostructured Si electrode materials in LIB, including specific capacity, capacity retention, Coulombic efficiency, and rate capability, was investigated. The nanostructured Si sample prepared at 1000 °C and 20 min (SiNS-20) showed the best electrochemical performance, delivering 3379 mAh g-1 for the second discharge specific capacity when cycled at a rate of 0.5 C, corresponding to the highest possible Li-Si phase of Li15Si4. The discharge capacity remained at 2197 mAh g-1 after 50 cycles with a high Coulombic efficiency of 97%, showing promising performance as LIB electrodes. More importantly, the synthetic approach of nanostructured Si directly on a conductive substrate provides a method towards the binder-free and carbon-free electrode design for use in LIBs.