Feasible preparation of Cu6Sn5 alloy thin-film anode materials for lithium-ion batteries from waste printed circuit boards by electrodeposition

Abstract Homogeneous and three-dimensional structural Cu6Sn5 alloy thin-film composite materials are successfully fabricated by efficiently electrodepositing the acidic leaching solution of waste printed circuit boards with the pH value adjusted to 10 at different current densities, which are confirmed by inductive coupled plasma-optical emission spectrometer, scanning electron microscope, and X-ray diffraction. When the Cu6Sn5 alloy thin-film composite materials electrodeposited at 5 mA/cm2 are employed as anode materials for lithium-ions batteries, the assembled coin cells can deliver initial discharge and charge specific capacity of about 617 and 502 mAh/g at 100 mA/g, respectively, and can retain a discharge specific capacity of 448 mAh/g after 25 cycles. Moreover, the cells assembled with Cu6Sn5 alloy anodes can exhibit an enhanced lithium-ion diffusion coefficient of 5.045 × 10−16 cm2/s with a lower transfer resistance of 63.43 Ω. Those results may provide an effective strategy for the resource utilization of low-value wastes into copper‑tin alloy thin-film electrode materials.