Selective Electrodeposition for Lithium-Ion Battery Recycling—Tuning Interfacial Chemistry for Selective Cobalt and Nickel Recovery

The recovery of transition metals from battery recycling streams is a critical challenge for materials circularity in the future, especially with the growing demand on battery-related critical elements. Electrochemical separation approaches have been gaining traction as a modular and electrified platform for ion-selective recovery. However, key transition metals in batteries such as cobalt and nickel often possess close reduction potentials in aqueous media, thus impeding selective recovery by electrodeposition. Here, we overcome this challenge by combining electrolyte design with interfacial control, to enhance the selectivity between cobalt and nickel. First, through highly concentrated chloride solutions, we can discriminate between the two metals by charge, and through the application of charged polyelectrolytes, we can further enhance separation factor during electrodeposition. We implement this strategy for the recovery of cobalt, nickel, and manganese from commercially-sourced lithium ion batteries, and demonstrate the recovery of high purity transition metals. Finally, we discuss parallel directions in developing continuous electrochemical approaches for the selective recovery of lithium. Overall, we believe that electrochemical separations can play an important role in enabling sustainable and energy-efficient battery recycling technologies.