Engineers at Rice University have developed a new method to extract purified active materials from lithium-ion battery waste.

“With the surge in battery use, particularly in EVs, the need for developing sustainable recycling methods is pressing,” says James Tour, Ph.D., professor of materials science and nanoengineering at Rice University.

According to Tour, traditional recycling techniques typically involve breaking down battery materials into their elemental forms through energy-intensive thermal or chemical processes that are costly and have significant environmental impacts.

Tour and his colleagues discovered that magnetic properties can facilitate the separation and purification of spent battery materials. They use a method known as solvent-free flash Joule heating (FJH). This technique involves passing a current through a moderately resistive material to rapidly heat and transform it into other substances.

Using FJH, the Rice engineers heated battery waste to 2,500 Kelvin within seconds, creating unique features with magnetic shells and stable core structures. The magnetic separation allowed for efficient purification.

During the process, cobalt-based battery cathodes—commonly used in EVs and associated with high financial, environmental and social costs—unexpectedly showed magnetism in the outer spinel cobalt oxide layers, allowing for easy separation. This approach resulted in a high battery metal recovery yield of 98 percent, with the value of battery structure maintained.

“Notably, the metal impurities were significantly reduced after separation, while preserving the structure and functionality of the materials,” explains Tour. “The bulk structure of battery materials remains stable and is ready to be reconstituted into new cathodes.”