Mounting demand for lithium-ion batteries to power electric vehicles and consumer electronics underscores the need for critical minerals as well as sustainable recycling technologies. As available recycling methods are often energy-intensive processes that generate substantial volumes of wastewater, a more sustainable technology for recovering battery materials was devised by Rice University researchers.

The two-step flash Joule heating-chlorination and oxidation process eliminates the use of strong acids to separate lithium, cobalt and graphite with purities exceeding 95% from spent lithium-ion batteries; recovery yields are in the 85% to 97% range. Battery materials are briefly heated with chlorine gas, which breaks them down. They then undergo a second heating in air, transforming most of the metals into forms that can be separated from lithium. Because lithium does not form an oxide as easily as other metals, it remains as the chloride, which can be easily extracted using water in a closed-loop condenser system.

The scalable, acid-free recycling approach described in Advanced Materials consumes about half as much energy, 95% fewer chemicals and significantly lower costs compared to existing methods.