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 Cu2Sb/Cu electrode has been synthesized via replacement reaction as an anode for sodium-ion batteries (SIBs). The thickness of Cu2Sb formed on Cu foil can be facilely tuned by adjusting the concentration of Sb3+ 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 Cu2Sb/Cu is investigated by using ex situ X-ray diffraction and transmission electron microscopy. The porous Cu2Sb nanoparticle film and its intrinsic contact with the Cu foil result in the good electrochemical performance. This facile synthetic route for the integrity of Cu2Sb 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.