Cu-doped Sb-Zn alloy anodes tailored by novel pulse electrodeposition achieving robust sodium storage

Abstract

Sodium-ion batteries (SIBs) have garnered significant attention as cost-efficient and expandable energy conversion devices. Nonetheless, their further utilization is impeded by the rapid deterioration in the capacity of anode materials during cycling. Herein, we have successfully introduced both active (Zn) and non-active (Cu) metal components into Sb by fabricating Cu-doped Sb-Zn (SZC-N) anodes through a template-free novel pulse potential electrodeposition (NPPED) approach. The introduction of Cu demonstrated a crucial role in directing the formation of the uniform structure. On the other hand, active “Zn” increases overall capacity and serves as a cushion against the volume expansion of Sb. Notably, the SZC-N exhibits enhanced charge diffusion while maintaining the structural integrity of the electrode, making it a promising choice for SIBs. Interestingly, the SZC-N electrode demonstrated remarkable cycling and rate performance, manifesting an excellent reversible capacity of 380.9 mAh·g−1 after 250 cycles, with an outstanding capacity retention of 80 % when operated at 1 C. Furthermore, it achieved a noteworthy capacity of 454.1 mAh·g−1 at a high current density of 10 C. In contrast, both the SZC-R and SZ-C anodes only yielded 52.9 and 3.9 mAh·g−1 (after 250 cycles), moreover, delivering inferior rate performance. The increased cyclic performance of the SZC-N electrode can be ascribed to the presence of a Cu network, which facilitates charge transport and promotes the stabilization of the electrode structure. The findings suggest that binder-free anode materials produced through the NPPED method present a promising opportunity for SIBs.