ZnSnSb2 anode: A solid solution behavior enabling high rate capability in Li-ion batteries

Abstract

ZnSnSb2 intermetallic alloy as anode material for Li-ion batteries has been investigated for the first time in this work. This material is able to deliver a high capacity of 615 mAh/g for 200 cycles at 4C (a current density of 0.25 A/g) with a good a coulombic efficiency exceeding 99.3%. Furthermore, the electrode material exhibits a high rate capability between C/5 (12.6 mA/g) and 10C (630 mA/g), with a reversible capacity loss of 19% and a polarization increasing of only 0.05 V. Among all reported MSnSb (with M = Ag, Ti, Cu…) alloys, ZnSnSb2 exhibits the most outstanding rate capability and long cycling life. The observed behavior can be linked not only to the quasi-topotactic de/lithiation reaction between the ZnSnSb2 and Li3Sb but also to the solid solution mechanism evidenced from operando X-ray diffraction analysis. This suggests that the electrode exhibits a great resistance to the volume expansion and the mechanical stress during cycling even at high cycling rates (10C).