In situ x-ray absorption studies of electrochemically induced phase changes in lithium-doped InSb

We report a comprehensive analysis of in situ x-ray absorption spectroscopy data that provide detailed information about phase transformations of the III-V semiconductor InSb, induced by electrochemical insertion of Li and extrusion of indium. Upon discharging a Li/InSb cell, In is extruded from the zinc-blende-type InSb structure and replaced by Li. Although more than 90% of the In is displaced from the structure, the Sb fcc sublattice remains stable at all degrees of lithiation. This process is reversible. However, in the fully charged state, about 40% of the In remains outside the matrix as In metal, leaving a corresponding number of Schottky vacancies in a ${\mathrm{In}}_{1\ensuremath{-}y}\mathrm{Sb}$ defect structure. The discussion of this paper focuses on the ease and reversibility of the phase changes in InSb electrodes, which is attributed to the stability of the Sb fcc sublattice at all states of discharge and charge, to the lattice compatibility of the different phases, and to the absence of significant charge gradients.