The effect of metallic coatings and crystallinity on the volume expansion of silicon during electrochemical lithiation/delithiation

► We use in-situ and ex-situ TEM to study the reaction of silicon nanowires with lithium. ► Conformal copper coatings fracture during NW expansion. ► Copper coatings play a role in suppressing volume expansion. ► Lithiation of single-crystal, polycrystalline, and amorphous nanowires is compared.