Recycling Lithium-ion Battery Cathodes Using Deep Eutectic Solvents
As the consumption of lithium-ion batteries (LIBs) for the transportation and consumer electronics sectors continues to grow, so does the pile of battery waste. Lithium-ion battery waste retains value particularly in the form of metal ions in the cathode part of the device, but few standardised methods exist to extract, recover, and reuse these precious metals. Such metals can be extracted using environmentally-friendly deep eutectic solvents which is safer than other corrosive hydrometallurgical methods which typically use strong acids, or high-energy pyrometallurgical methods which incinerate and grind waste battery material at temperatures beyond 1000˚C. The deep eutectic solvents (DES) can be made from commercially available commodities such as choline chloride and ethylene glycol which makes them good candidates for industrial scales. The battery recycling industries could benefit from the use of safer solvents that can still effectively extract and recover precious metals from spent lithium-ion batteries for reuse in other applications.
Starting with disassembly of the LIB, cathode waste is inserted into a DES, which is then heated and stirred. Extraction of cobalt and lithiumm ions occurs through dissolution, and at this step, aluminium foil, binder and conductive carbon can be recovered separately when the leachate is filtered. Cobalt compounds can then be recovered either through precipitation or electrodeposition, allowing reutilization of these valuable materials.