Plasma and lemon juice: Milder method retrieves nearly 95% of critical minerals in battery waste

Critical minerals such as those used in lithium-ion batteries come in limited supply and are concentrated in specific regions around the world. Securing a reliable supply of these materials is a priority for governments worldwide, yet most spent batteries end up in landfills, leeching toxic chemicals into the environment.

The researchers used a brief microwave-induced plasma treatment to recover nearly all of the valuable metals in battery waste using room-temperature, comparatively mild solvents, including citric acid. The process also regenerated graphite — the main material in a battery’s anode. “With plasma pretreatment, almost 95% of metals, including lithium, can be recovered from battery black mass using nothing harsher than the acid found in a lemon,” said Chandrasekhar, who is part of Pulickel Ajayan’s research group at Rice.

Current recycling protocols involve shredding battery waste down to a substance known as black mass, which contains minerals such as lithium, cobalt, nickel, graphite, manganese, aluminum and more. Processing black mass for mineral extraction typically requires energy-intensive industrial processes involving high temperatures and strong acids, and recovery rates are uneven. Lithium can be particularly difficult to capture efficiently, and graphite — which makes up roughly 22% of the battery’s weight — is rarely returned to batteries because it gets damaged during conventional recycling processes.

Source: Eurek Alert!