Researchers Develop "Relithiation" Technique to Recycle, Restore Old Lithium-Ion Batteries

Formerly-depleted electrodes show a charge capacity close to that of brand new equivalents, and could solve the battery waste problem.

A team of researchers from Washington University, Virginia Polytechnic, and Shanghai Jiao Tong University have developed a technique for turning spent lithium-ion battery electrodes back into new lithium-ion batteries — potentially solving their waste problem.

Lithium-ion batteries are ubiquitous thanks to their high energy density, but their ubiquity is a problem: They frequently end up in landfill, polluting the environment, despite the fact that the batteries still contain useful materials — but simply no longer hold a charge thanks to a depleted electrode. While recycling programs do exist, the low cost of fresh lithium-ion batteries and the expense of processing means uptake hovers at around five percent — a figure the researchers aim to dramatically improve.

"Since 95 percent of the materials are still there and usable, we wanted to see if we could regenerate the complete lithium cobalt oxide compounds directly instead of recovering individual elements and then putting them together to be a useful compound," explains Zhen He, co-author on the paper. "We used an electrodeposition process where we deposited the lithium ions on the waste electrodes driven by the electricity that creates the electric field to absorb the ion onto the electrode. We can add an additional amount of lithium-ion into the waste electrode, and you get a complete formula that allows you to reuse those materials."

The team's process directly regenerates the cathode material in lithium-ion batteries, adding fresh lithium ions in a process called "relithiation." Once treated, the regenerated electrode had a charge capacity of 136mAh/g⁻¹ — extremely close to the 136mAh/g⁻¹ of a brand new commercial electrode.

The team's work has been published under closed-access terms in the journal ACS Sustainable Chemistry & Engineering, while the team is going to build on the initial feasibility study ahead of hopeful commercialization of the technique.