High-performance and sodiation mechanism of a pulse potential-electrodeposited Sb-Zn alloy as an anode for sodium-ion batteries

Antimony-based alloys have attracted extensive attention as promising anode materials in sodium-ion batteries (SIBs) due to their high theoretical capacity. However, the current process used to fabricate Sb-based alloys results in an almost powdery product, which leads to inadequate ion penetration and impedes electron transport when the alloys mix with nonconductive binders. Here, we have developed an advanced pulse potential electrodeposition method to prepare binder-free Sb-Zn alloys on copper foil and form a self-supported anode of SIBs. The Sb-Zn alloy anodes exhibited remarkably stable and robust Na-ion storage performance. Compared with the constant potential electrodeposition method, the Sb-Zn composite prepared using pulse potential electrodeposition exhibits higher charge/discharge capacities, a higher rate capability and superior cycle performance. The initial charge/discharge capacities of the Sb-Zn alloy anode are 377 mAh·g−1/453 mAh·g−1, and the first coulombic efficiency reaches to 83%. The specific capacity retention is 70% after 320 cycles at a charge/discharge current density of 300 mA·g−1. The reaction mechanism and reaction kinetics were determined by performing operando X-ray diffraction spectroscopy and cyclic voltammetry investigations. This work provides a potential new starting point for large scalable manufacturing of high-performance Sb-based anodes for SIBs.