Silicon Nano Wires Anodes for High-Performance Lithium Ion Batteries

Abstract

We report on the scalable synthesis and characterization of novel architecture three-dimensional high-capacity amorphous Silicon Nanowires (SiNWs)-based anodes, with a quarter of the thickness of common graphite anode. The SiNWs were grown in a novel, catalyst free process, on a thin stainless steel (SS) net. With the use of two and three electrodes coin cells we focus on studying their electrochemical performance and degradation mechanisms. By using our novel, low cost and high mass loading chemical vapor deposition (CVD) procedure we synthesized anodes that have shown stable cycle life for over 600 cycles and provided capacities of up to 6mAh/cm2, very low (<10%) irreversible capacity and good compatibility with commercial cathodes. Notably, it was found that the growth of the solid electrolyte interphase (SEI) thickness and its concomitant increase in resistivity, represents the major reason for the observed capacity loss of the SiNWs-based anodes. Our anodes have been coupled with commercial cathodes (LFP and NCA), and have the potential to increase the energy density of LIBs by over 40%. In order to prove the scalability of our anodes, they have been successfully incorporated in industrial hardware cylindrical cells, proving they are a viable candidate for anodes of the next generation lithium ion batteries for portable applications and electric vehicles. Most recently, these anodes have successfully been cycled in all solid state cells consisting of solid polymer electrolytes, paving the way for safer, more durable LIBs.