Prospects for fully recycling all components of rechargeable solid-state lithium batteries improve with a reconfigured device design developed at Pennsylvania State University.

Recycling of these batteries has primarily focused on metals recovery while other components are ultimately discarded because they mix during the recycling process and form a black mass. This formation contains essential battery materials, such as solid electrolytes, but are difficult to recover. To facilitate capture of these otherwise wasted ingredients, researchers inserted two polymer layers at the interfaces between the electrode and the electrolyte prior to the start of the recycling process.

“We proposed that by dissolving the polymer layer during the recycling process, you can easily separate the electrode from the electrolyte,” explained researcher Yi-Chen Lan. “Without the polymer layer separating them, you would have the electrode and electrolyte mixed together, which makes them hard to recycle.”

The interfacial layers of flexible lithium bis(fluorosulfonyl)imide doped polypropylene carbonate function as sacrificial materials to enable clean separation and direct recycling. Cold sintering was applied to the recovered metals and electrodes to form a composite, which was then used to reconstruct the battery with the addition of polymer layers. As reported in ACS Energy Letters, the battery constructed with recycled components demonstrated 92.5% to 93.8% of its original discharge capacity.