Utilization of underwater electrical pulses in separation process for recycling of positive electrode materials in lithium-ion batteries: Role of sample size

The amount of generated waste of lithium-ion batteries (LiBs) that are used in automobiles is expected to increase because of increases in EV usage. Thus, it is required to recover strategic elements, such as lithium, cobalt, nickel, and manganese in the positive electrodes (PEs) found within LiB. In recent years, a direct application of electrical pulsed power to PEs has been reported to separate the active material layer from the aluminum foil in PEs. The electrical pulsed-discharge treatment enables the separation of the active materials from the aluminum foil without changing in a significant manner the chemical composition of the materials. In this study, we investigated the influence of length of rolled PE samples on the separation of active material from the aluminum foil of PE via the electrical pulsed-discharge treatment. Calculated energy and charging voltage for specific sample sizes were applied to PE samples installed in discharging electrodes in water. After the electrical pulsed-discharge treatment, up to 98.8% cobalt and 6.7% aluminum were recovered from liberated particles of 8 mm or less. For a longer length of PE sample, the separation efficiency of cobalt for aluminum was higher, and the aluminum contamination for active material particles was lower. The internal circuit resistance should be reduced as much as possible to reduce the circuit energy consumption. In terms of energy efficiency, a longer, narrower, and thinner aluminum foil had positive effects in the separation of the positive electrode by the electrical pulsed-discharge treatment.