Vegetable Oil is being used by Scientists to recycle Lithium-Ion batteries

Researchers based at the University of Leicester have recently developed a nanoemulsion method which utilises water and cooking oil in order to recover metals from battery waste. This method sustainably extracts valuable metals from a waste product that is made up of used batteries.

This innovative patent pending technology works through allowing lithium-ion battery black mass, to be directly purified whilst at room temperature, within a matter of minutes. This black mass is a low-value mixture of anode and cathode, as well as other materials.

This research was conducted and led by Professor Andy Abbott, as well as, Dr Jake Yang and it all occurred at the University of Leicester, under the Faraday Institution’s ReLiB project.

It is common knowledge that oil and water do not mix until soap is also involved, however recent research has proven that using ultrasound makes it possible to create nano-droplets of oil which remain stable for weeks. Discovering this became a huge stepping stone in the journey to discovering that oil nano-droplets have the ability to purify battery waste, which is more commonly known as ‘black-mass’. This is the usual name for battery waste, because it ‘contains a mixture of carbon (graphite) and valuable lithium, nickel and cobalt metal oxides (NMC).’ Throughout this process, the oil nano-droplets are able to stick to the surface of the carbon and act as a kind of glue, in order to ‘bind hydrophobic graphite particles together.’ Doing this will lead to the formation of large oil-graphite conglomerates which then float on water, resulting in the valuable and hydrophobic lithium metal oxides being left untouched. Once this process is complete, it is possible to skim off the oil-graphite conglomerate and just leave the pure metal oxides behind.

Whilst ‘normal’ recycling techniques that are currently in use within the market, operate with furnace heat treatment and therefore increase the carbon footprint of the EV value chain, the new emulsion technique developed by the researchers, opens the door to short-loop recycling of lithium-ion batteries. This new technique is a huge step forwards for the battery recycling industry and it means that the battery-grade crystalline structure of the recovered materials is no longer destroyed within the process. Furthermore, the new process also allows the ‘remanufacturing of the recovered material directly back into new battery cells’ which is a large improvement on the pyro/ hydrometallurgical methods. Not only is this better for the individual batteries and pieces of material, but the updated method could also mean that the battery supply chain becomes more sustainable, as well as cheaper.

Dr Jake Yang from the University of Leicester School of Chemistry commented, “This quick, simple and inexpensive method could revolutionise how batteries are recycled at scale. We now hope to work with a variety of stakeholders to scale up this technology and create a circular economy for lithium-ion batteries.”