Preparation of Cu_xSb/Ti Electrodes by Electrodeposition and their Sodium Storage Performance

Abstract To explore a simple and green synthesis method for constructing high‐performance Sb‐based electrodes for sodium‐ion batteries, four Cu_xSb alloy films with different compositions are deposited on Ti substrates through constant current step technique using SbCl₃ and CuCl₂ ⋅ 2H₂O as raw materials (referred to as Cu_xSb/Ti). Among them, the prepared Cu_1.33Sb/Ti electrode exhibits the best comprehensive electrochemical performance. At a current density of 0.2 A g⁻¹, the electrode has a first reversible capacity of 385.2 mAh g⁻¹ with a coulombic efficiency of 76.7%. After 150 cycles, the reversible capacity remains at 343.5 mAh g⁻¹ with a capacity retention of 89.2%. A stable discharge capacity of 290.5 mAh g⁻¹ can be obtained at a current density of 2 A g⁻¹. The excellent electrochemical performance is attributed to the introduction of inactive Cu, which alleviates the destruction of the volume variation during charging and discharging and improves the conductivity of the electrode. At the same time, CuTi alloy formed from Cu with Ti substrate enhances the bonding force between the alloy film and the substrate. This work provides a new approach for the preparation of Sb‐based alloy anodes for sodium‐ion batteries with low cost, high performance, and free of adhesives and conductive agents.