A team of Brazilian researchers have created biodiesel using old cooking oil and waste from lithium batteries, in a breakthrough which could provide a global use for spent electric car batteries.
The team used waste cooking oil collected from fast food restaurants and homes, combining it with metal hydroxides including lithium from old batteries, to produce the fuel.
Waste-based biofuels made from old oils are seen as a more sustainable alternative to biofuels made with crops such as rapeseed, which can take land away from agriculture or nature reserves.
The experiment produced chemically sound biodiesel as well as glycerol, which can be used to produce food sweeteners or skin treatments.
“We were surprised that what came out was not only some results, but actually very good results related to the yield production,” study author Gilberto Maia de Brito said. “The fast phase separation and the main chemistry and physics properties of that biodiesel produced from lithium were also surprising.”
The number of lithium ion batteries in operation is set to soar in the coming years, as global electricity systems adopt battery energy storage and drivers around the world switch to electric cars.
But lithium batteries have a finite shelf life, and experts are worried about how to ensure old batteries don’t end up as huge waste mountains. Only around five per cent of lithium-ion batteries are recycled.
If it could be scaled up, lithium biodiesel could open up a new market for waste batteries, the researchers hope. “The recycling process not only removes Li-ion battery wastes and oily contaminants from the environment but also enables the generation of a green power source,” the study, published in the Journal of Renewable and Sustainable Energy, says.