Eco-friendly strategy for advanced recycling waste copper from spent lithium-ion batteries: Preparation of micro-nano copper powder

Massive spent lithium-ion batteries (LIBs) were emerged worldwide as a consequence of the extensive use in energy storage applications. The recovery of cathode electrode materials from spent LIBs has received great attention due to economic benefits, which has led to the neglect of the deep utilization of low-value copper current. The present study focuses on the selective crushing of copper foil and the preparation of micro-nano copper powders through eco-friendly leaching and reduction processes. The occurrence characteristics of copper in the anode material obtained by disassembling the battery after discharge pretreatment were first analyzed, SEM + EDS detection shows that graphite with thickness of tens of microns is attached to the surface of copper foil. Subsequently, the application of mechanical force promoted the graphite to detach from the collector, and the results indicate that significant selective crushing leads to the enrichment of copper foil in coarse-grained particles. Further, an ammonia leaching method was used to leach copper gently. The leaching kinetic behavior of copper foil particles with different particle sizes was analyzed. The diffusion controlled shrinking core model can accurately describe the leaching behavior of copper foil particles in leaching process. The activation energies of +2 mm, 2–1 mm, and 1–0.5 mm are 15.04 kJ/mol, 11.61 kJ/mol, and 8.21 kJ/mol, respectively. Undissociated graphite has negative impact on the leaching behavior, and reduction in the particle size of the copper foil can enhance the leaching behavior. Finally, the glucose and ascorbic acid system reducing reaction promotes the transformation of the copper ions in the leaching solution into regular shaped copper nanoparticles. SEM and XRD results show that high purity copper nanoparticles with hundreds of nanometers was successfully prepared. This study provides an eco-strategy and value-added recovery approach to address the challenges of full component utilization of spent LIBs.