Three-dimensional structural Cu₆Sn₅/carbon nanotubes alloy thin-film electrodes fabricated by in situ electrodeposition from the leaching solution of waste-printed circuit boards

Tin-based materials are very attractive anodes because of their high theoretical capacity, but their rapid capacity fading from volume expansions limits their practical applications during alloying and dealloying processes. Herein, the improved binder-free tin-copper intermetallic/carbon nanotubes (Cu₆Sn₅/CNTs) alloy thin-film electrodes are directly fabricated through efficient in situ electrodeposition from the leaching solution of treated waste-printed circuit boards (WPCBs). The characterization results show that the easily agglomerated Cu₆Sn₅ alloy nanoparticles are uniformly dispersed across the three-dimensional network when the CNTs concentration in the electrodeposition solution is maintained at 0.2 g·L⁻¹. Moreover, the optimal Cu₆Sn₅/CNTs-0.2 alloy thin-film electrode can not only provide a decent discharge specific capacity of 458.35 mAh·g⁻¹ after 50 cycles at 100 mA·g⁻¹ within capacity retention of 82.58% but also deliver a relatively high reversible specific capacity of 518.24, 445.52, 418.18, 345.33, and 278.05 mAh·g⁻¹ at step-increased current density of 0.1, 0.2, 0.5, 1.0, and 2.0 A·g⁻¹, respectively. Therefore, the preparation process of the Cu₆Sn₅/CNTs-0.2 alloy thin-film electrode with improved electrochemical performance may provide a cost-effective strategy for the resource utilization of WPCBs to fabricate anode materials for lithium-ion batteries.