Shearing-enhanced mechanical exfoliation with mild-temperature pretreatment for cathode active material recovery from spent LIBs

Abstract

The conventional approaches for recovering valuable metals from spent lithium-ion batteries (LIBs) suffer from heavy dependence on chemical reagents, high energy consumption, and low recovery efficiencies. In this study, we developed a shearing-enhanced mechanical exfoliation combined with mild-temperature pretreatment (SMEMP) method. The method achieves high-efficiency exfoliation of the cathode active materials that remain strongly adhered to polyvinylidene fluoride after it melts during mild pretreatment. The pretreatment temperature was decreased from 500–550 °C to 250 °C, the duration was decreased to 1/4–1/6 of the traditional pretreatment duration, and the exfoliation efficiency and product purity reached 96.88% and 99.93%, respectively. Despite the weakening thermal stress, the cathode materials could be exfoliated by strengthened shear forces. Compared with other traditional methods, the superiority of this method in temperature reduction and energy saving was established. The proposed SMEMP method is environmentally friendly and economical, and it offers a new route for the recovery of cathode active materials from spent LIBs.