Quantitative Fracture Strength of Lithiated Tin Oxide Nanowires by In-Situ SEM Tensile Experiments

The quantitative fracture strength of lithiated and pristine tin oxide (SnO2) nanowires was gathered from in situ scanning electron microscope (SEM) mechanical tests using a micro electromechanical system (MEMS) uniaxial tensile testing device. Stress values were calculated from load and displacement data from an inSEM nanoindenter tip while strain values were obtained using digital image correlation (DIC) from in situ SEM test images. The SnO2 nanowires were synthesized using the vapor-liquid-solid (VLS) growth mechanism on stainless steel substrates using a gold (Au) catalyst. Ex-situ lithiation of the SnO2 nanowires was performed directly using the stainless steel growth substrates by the electrochemical half-cell method which did not involve the use of binders or conductive agents. The fracture strength decreased from 2.4 GPa +/- 0.2 GPa for the pristine SnO2 nanowires to 814.8 MPa +/- 429.7 MPa for the lithiated SnO2 nanowires. This study provides the first quantitative mechanical data for pristine and lithiated SnO2 nanowires.