Ultrasonic Delamination Could Make Battery Recovery Quick & Green

Researchers from the universities of Birmingham and Leicester, working at Faraday Institution on ‘ReLiB’, a battery recycling research project, claim that ultrasonic delamination is a fast, sustainable, and less energy-intensive method to recycle batteries.

While old batteries are usually shredded and treated with fire or aqueous solvents to recover precious metals, a process that uses a lot of energy and releases toxic waste, these U.K. scientists have advocated the use of ultrasonic sound waves for battery recovery in their paper “Lithium-ion Battery Recycling Using High-intensity Ultrasonication,” recently published in the journal Green Chemistry.

The paper, which argues that this process could also yield higher-purity materials, was co-authored by Chunhong Lei, Iain Aldous, Jennifer Hartley, Dana Thompson, Sean Scott , Rowan Hanson, Paul Anderson, Emma Kendrick, Rob Sommerville, Karl Ryder, and Andrew Abbott.

According to the scientists, decarbonisation of energy will rely heavily, at least initially, on the use of lithium ion batteries for automotive transportation. The projected volumes of batteries necessitate the development of fast and efficient recycling protocols. Current methods are based on either hydrometallurgical or pyrometallurgical methods. The development of efficient separation techniques of waste lithium ion batteries into processable waste streams is needed to reduce material loss during recycling.

In their paper, they show a rapid and simple method for removing the active material from composite electrodes using high powered ultrasound in a continuous flow process. Cavitation at the electrode interface enables rapid and selective breaking of the adhesive bond, enabling an electrode to be delaminated in a matter of seconds. This enables the amount of material that can be processed in a given time and volume to be increased by a factor of approximately 100. It also produces a material of higher purity and value that can potentially be directly recycled into new electrodes.

The researchers say that the efficiency of the delamination process is strongly affected by the type of polymer binder with water-dispersible binders such as SBR/CMC being more rapidly stripped. Delamination could thus be further optimised using wetting agents and pH modification. Production scrap from the batteries could be rapidly recycled by simply wetting the active material/binder mixture with an organic solvent.

High rates of material recovery and throughput coupled with the ease of process scale up make high-powered ultrasonic delamination a step-change in battery recycling, the scientists conclude.