High Anode Performance of in Situ Formed Cu₂Sb Nanoparticles Integrated on Cu Foil via Replacement Reaction for Sodium-Ion Batteries

A scalable and binder-free Cu 2 Sb/Cu electrode has been synthesized via replacement reaction as an anode for sodium-ion batteries (SIBs). The thickness of Cu 2 Sb formed on Cu foil can be facilely tuned by adjusting the concentration of Sb 3+ and reaction time. A high capacity of 318.4 mAh g –1 is obtained at 0.08 A g –1, and a capacity retention of 98.5% is also maintained after 200 cycles at 0.8 A g –1 . The reaction mechanism of the as-synthesized Cu 2 Sb/Cu is investigated by using ex situ X-ray diffraction and transmission electron microscopy. The porous Cu 2 Sb nanoparticle film and its intrinsic contact with the Cu foil result in the good electrochemical performance. This facile synthetic route for the integrity of Cu 2 Sb nanoparticles and Cu foil allow for simplifying the preparation processes of SIBs in large-scale applications and is applicable for advanced material design and synthesis.