Laser Porosificated Silicon Anodes for Lithium Ion Batteries

This study presents the first laser porosificated silicon anode for lithium‐ion batteries. The pulsed laser induced pore creation improves the cycling stability of the d = 210 nm thick sputtered thin film anodes compared to plain Si. Galvanostatic cycling with a charge capacity limited to C = 932 mAh g−1 and a 2C current rate shows a stable cycling for more than N = 600 cycles. After N = 3000 cycles the laser porosificated and crystallized Si has a remaining capacity of C3000 > 120 mAh g−1. Postmortem scanning electron microscopy images after N = 3000 cycles prove that the laser porosification reduces cracks in the active layer. In lithium batteries, silicon anodes expand up to 250% in volume during lithium insertion, which mechanically damages the silicon. The morphology of silicon must be adjusted for this volume expansion. Laser porosification uses single laser pulses to produce porous structured silicon films, which improves the cycling stability of the silicon anodes.