Nanoscale Electrochemistry via Lithium Focused Ion Beam

We report progress in developing Li+ focused ion beams (FIB) as a novel probe for exploring nanoscale electrochemistry in battery-relevant materials. This work focuses on implantation of lithium ions in crystalline silicon to benchmark this technique and builds on recent, qualitative studies of FIB implantation in Sn microspheres [Takeuchi et al. JES 163 (6), A1010-A1012]. FIB implantation opens the possibility of precise spatial control of nanoscale lithium concentration though variation of the beam positioning and current. Experiments are performed in vacuo without the presence of electrolytes or associated solid-electrolyte interface. The Li+ ion beam operates with energies ranging from 0.5 to 5 keV, currents up to 15 pA, and minimum spot size of 27 nm using a magneto-optical trap ion source (MOTIS).