One-step chemical dealloying synthesis of a multi-structured Cu2Sb/Sb2O3/Cu/Cu2O nanocomposite anode for advanced sodium-ion batteries

While Sb-based anodes for sodium-ion batteries (SIBs) are attractive for their high gravimetric capacities, they suffer from poor cyclability and sluggish charge storage kinetics due to large volume changes and multiple phase transformations. In this study, we developed a multi-structured Cu₂Sb/Sb₂O₃/Cu/Cu₂O nanocomposite by a simple one-step dealloying strategy. As an anode material for SIBs, this nanocomposite exhibits good cycling performance, maintaining a reversible capacity of 223 mAh g⁻¹ for over 200 cycles at a current density of 0.2 A g⁻¹. Furthermore, the Cu₂Sb/Sb₂O₃/Cu/Cu₂O nanocomposite demonstrates twice the sodium-ion diffusion rate compared to pure Sb. The improved electrochemical performance can be attributed to the synergistic effects of the layered NP-Cu₂Sb, Sb₂O₃ nanoparticles and NP-Cu/Cu₂O, which provide efficient pathways for ion and electron transport, thereby enhancing the rate capability of the electrode. Additionally, the inactive Cu within the Cu₂Sb and the formation of Na₂O as an intermediate product effectively accommodate the volume changes that occur during (de)sodiation, preventing the pulverization of the nanocomposite. These findings highlight the potential of Sb-based materials with unique architectures and composite systems as rechargeable SIBs anodes, and this work serves as inspiration for the further development of novel alloy-type electrodes through the facile dealloying method.

Graphical abstract

Sb-based anodes for sodium-ion batteries have high capacities but poor cyclability. This study introduces a multi-structured Cu₂Sb/Sb₂O₃/Cu/Cu₂O nanocomposite with improved cycling performance and double the sodium-ion diffusion rate, inspiring further electrode development.