Electrochemistry and in-situ X-ray diffraction of InSb in lithium batteries

The electrochemical reactions of lithium with the intermetallic compound, InSb, were studied in lithium coin cells using laminate electrodes fabricated from either singlecrystal InSb wafers or ball-milled samples. In-situ X-ray diffraction data show that the InSb zinc-blende framework is unstable to extensive reaction with lithium; In is extruded from a fixed Sb lattice during `dischargeʹ and is partially incorporated back into the lattice during `chargeʹ. Despite the loss of some In from the structure, the indium antimonide electrode provides capacities in excess of 300 mAh/g with excellent reversibility. Cyclic voltammetry was used to study the electrochemical processes in greater detail. Lithiated indium products are formed below ~600 mV versus Li. The electrode can be discharged at high rates, delivering 150 mAh/g at 3.6 mA/cm2 between 1.2 and 0.2 V versus Li. These data hold exciting prospects for the development of intermetallic insertion electrodes for practical room-temperature Li-ion cells.