Researchers at Penn State have innovated a new method to improve the recycling of solid-state lithium batteries.
The team has reconfigured the design of solid-state lithium batteries so that all of their components can be recycled efficiently.
Rechargeable solid-state lithium batteries are a disruptive technology in the battery sector that could one-day power consumer electronics with a single charge.
These batteries offer greater energy density than traditional lithium-ion batteries; however, recycling them is a major challenge.
Current recycling methods focus on the limited recovery of metals in the cathodes, with the rest ending up as battery waste.
The leader of the study, Enrique Gomez, believes the team’s innovation could prove pivotal in improving recyclability.
He explained: “As the need for rechargeable batteries grows, we need to think about the end-of-life of this technology.
“We hope our work highlights the possibilities in recycling solid-state batteries, with the help of some key design elements.”
Simplifying battery recycling
Recycling battery components typically results in a “black mass,” a mixture of valuable materials that are hard to separate.
Solid-state batteries exacerbate this issue as their solid electrolytes mix with the black mass during the recycling process.
Innovative polymer layer solution
To overcome this issue, the researchers inserted polymer layers between the electrode and electrolyte of coin cell batteries to simplify the recycling process.
These layers dissolve during recycling, allowing easy separation of the electrode from the electrolyte.
“We proposed that by dissolving the polymer layer during the recycling process, you can easily separate the electrode from the electrolyte,” said Yi-Chen Lan, doctoral student in chemical engineering and first author of the paper.
“Without the polymer layer separating them, you would have the electrode and electrolyte mixed together, which makes them hard to recycle.”
Using cold sintering, a method developed at Penn State, the team created a composite from the recovered materials.
This approach enabled the reconstruction and subsequent re-recycling of the entire battery.
Promising results
The recycled battery retained 92.5%-93.8% of its original capacity. While commercial use of all-solid-state lithium batteries is still developing, this research paves the way for designing recyclable batteries for future applications in devices like phones and laptops.
