The increasing global market size of high-energy storage devices due to the boom in electric vehicles and portable electronics has caused the battery industry to produce a lot of waste lithium-ion batteries. The liberation and de-agglomeration of cathode material are the necessary procedures to improve the recycling derived from spent lithium-ion batteries, as well as enabling the direct recycling pathway. In this study, the supercritical (SC) CO2 was innovatively adapted to enable the recycling of spent lithium-ion batteries (LIBs) based on facilitating the interaction with a binder and dimethyl sulfoxide (DMSO) co-solvent. The results show that the optimum experimental conditions to liberate the cathode particles are processing at a temperature of 70 °C and 80 bar pressure for a duration of 20 min. During the treatment, polyvinylidene fluoride (PVDF) was dissolved in the SC fluid system and collected in the dimethyl sulfoxide (DMSO), as detected by the Fourier Transform Infrared Spectrometer (FTIR). The liberation yield of the cathode from the current collector reaches 96.7% under optimal conditions and thus, the cathode particles are dispersed into smaller fragments. Afterwards, PVDF can be precipitated and reused. In addition, there is no hydrogen fluoride (HF) gas emission due to binder decomposition in the suggested process. The proposed SC-CO2 and co-solvent system effectively separate the PVDF from Li-ion battery electrodes. Thus, this approach is promising as an alternative pre-treatment method due to its efficiency, relatively low energy consumption, and environmental benign features.

The efficient recycling of spent anode material (SAM) from spent lithium-ion batteries (LIBs) is generally critical in terms of electronic waste recyclingas well as increasing resource shortage and environmental problems. This research reported a novel and green method to recycle lithium, copper foil, and graphite from SAM by water leaching treatment. The results indicated that 100% of graphite was exfoliated from the anode material and 92.82% leaching efficiency of lithium was obtained under the optimal conditions of 80 °C, 60 g/L, 300 rpm, and 60 min, respectively. This finding revealed that the SAM got a full liberation characteristic due to the removal of binder, which produced an ideal leaching lithium efficiency rivaling the acids\' performance. The mechanism of the liberation of SAM and lithium leaching is presented based on the analysis of results. The graphite was purified and recovered after water leaching treatment. Besides, lithium was recovered in the form of lithium carbonate (Li2CO3), and the copper foil was recovered in a sheet. This study endeavors to develop an economical and environmentally feasible plan to recycle graphite, copper, and lithium from SAM.

Proper disposal of spent lithium-ion batteries is beneficial for the resource recycling and pollution elimination. Full liberation of electrode materials, including the liberation between electrode material and current collector (copper/aluminum foils) and the liberation among electrode material particles, is the pivotal precondition for improving the recovery efficiency of electrode materials. In this article, authors attempt to carry out a summary of current technologies used in the liberation of electrode materials derived from spent lithium-ion batteries. However, specialized studies about the liberation of electrode materials are insufficient at present. This research clearly shows that: (1) Organic binder must be removed so as to improve the liberation and metallurgy efficiency of electrode materials; (2) A collaboration of varied technologies is the necessary process to achieve high liberation efficiency between electrode materials and copper/aluminum foils; (3) Pyrolysis may be a recommended technology for removal of organic binder because part of pyrolysis products can be recovered. Finally, an alternative recycling flowchart of spent LIBs is proposed.

Liberation and reduction of cathode material are the necessary procedures for improving the recycling efficiency of cathode material derived from spent lithium-ion batteries. In this research work, a pyrolysis technology was utilized to remove the organic binder and enhance liberation of electrode materials. At the same time, pyrolysis treatment can facilitate the thermal-reduction of Co3+ in LiCoO2 to Co2+ with surface organics, which lays a foundation for the subsequent reductant-free acid leaching. Results indicate that the crystal structure of pure LiCoO2 is not changed at a pyrolysis temperature of 600 °C, but LiCoO2 transforms to CoO, Li2CO3, LiF, and Li2O under the reduction action of HF, pyrolytic carbon, and additive carbon black. Water-impact crushing is synchronized with water-leaching to separate electrode materials from aluminum foil and recover Li element. Afterwards, reductant-free acid leaching technology can be utilized to recycle Li and Co from spent LiCoO2 batteries. Recovery efficiency of Li element in water-leaching process was up to 92.17% while the remaining 7.83% of Li and all Co elements were recovered during reductant-free acid leaching process. Based on the foundation analysis, the green chemical process for recovering valuable metals from spent lithium-ion batteries was proposed.

The metal in the waste printed circuit boards (WPCBs) is an excellent secondary metal resource. WPCBs were ground to dissociate, and impurities in the dissociated product were removed by gradient flotation to recover valuable metals in this study. The effects of crushing methods on size composition and dissociation state of the crushed products were studied. Then the gradient flotation experiment was designed to verify the natural floatability of ground materials. Grinding test shows that impact crushing has greater grinding fineness (-0.074 mm) than shear crushing, which is 42.14% and 26.18% respectively with 5 min grinding. The flotation test results illustrate that the natural floatability of impurities increases with the grinding fineness, that is, the yield of floats increases without flotation reagents. For impact crushing and shear crushing, the floats yields are 38.48% and 31.75% respectively, accompanied by 70.53% and 65.46% impurity removal for ground materials with 5 min grinding. Subsequently, 21.61% and 26.35% of impurities can be further removed with the aid of collector. Finally, the recovery of Cu in concentrate reaches 67.84% and 65.75%, respectively. FT-IR proves that the excellent floatability of particles is caused by the significant hydrophobic group. Mechanical grinding has been proved to have double effects of improving dissociation and natural floatability.