Two dimensional silicon nanowalls for lithium ion batteries

One-dimensional (1-D) nanostructures such as nanowires and nanotubes have been widely explored for anodes with high specific capacity in Li-ion batteries, which effectively release the mechanical stress to avoid structure pulverization. However, 1-D nanostructures typically have a high surface area, which leads to a large irreversible capacity in the first cycle due to a solid electrolyte interface (SEI) formation. Two dimensional (2-D) nanowalls can address the same challenges as 1-D nanostructures, with a much lower surface area. For the first time, we demonstrated a 2-D nanowall structure with silicon for Li-ion batteries. Excellent performance for the first Coulombic efficiency (CE) has been achieved. Such a 2-D nanowall structure can also be applied in other devices with improved performance where nanostructures are needed but a high surface area is problematic.