Researchers at the Korea Institute of Energy Research who conducted the study. From left: Song Jin-ju, principal researcher; Woo Jung-je, center director; and Song Jeong-hwan, student researcher. [Korea Institute of Energy Research]
Researchers at the Korea Institute of Energy Research who conducted the study. From left: Song Jin-ju, principal researcher; Woo Jung-je, center director; and Song Jeong-hwan, student researcher. [Korea Institute of Energy Research]

South Korean researchers have developed an eco-friendly technology that recycles spent electric vehicle batteries while significantly reducing the generation of heavy-metal-laden wastewater.

A team led by Woo Jung-je at the Korea Institute of Energy Research's Gwangju Clean Energy Research Center announced Tuesday that it had developed a solution-based process that resolves a longstanding obstacle in direct battery recycling — separating the current collector from the cathode — while simultaneously restoring degraded cathode materials to near-original condition.

Wastewater produced during conventional EV battery recycling can contain heavy metals that, if not properly treated, risk contaminating soil and groundwater. Cathode materials, which largely determine battery capacity, contain costly rare metals such as cobalt, making efficient recovery and reuse a critical technological goal.

The team focused on "direct recycling," an approach that restores cathode materials while preserving as much of the battery's original structure as possible. The central challenge is detaching the current collector, which adheres tightly to the cathode, without causing damage. Conventional methods required special solutions containing hazardous chemicals to overcome the strong bonding, and residues left inside the regenerated electrode degraded performance.

To solve this, the researchers turned to diethylene glycol. When spent cathode material is submerged in a diethylene glycol solution and heated to 130 degrees Celsius, an oxidation reaction produces glycolaldehyde, which weakens the adhesion between the cathode and the current collector, allowing effective separation.

Performance recovered to levels nearly matching new materials. NCM (nickel-cobalt-manganese) cathode material, commonly used in electric vehicles, recovered 99.1% of its original capacity, while LFP (lithium iron phosphate) cathode material recovered 99.7%.

When degraded cathode material extracted from a 50 Ah EV battery was restored and applied to a small test cell, discharge capacity increased from 30.6 mAh to 34.6 mAh — confirming the process's potential for real-world application beyond the laboratory.

Song Jin-ju, the principal researcher who led the study, said the process recycles spent battery cathode materials without dissolving them, reducing environmental pollution from wastewater and cutting the energy required for processing. "The process is simple and does not require a separate sealed environment, making it highly applicable to industrial settings," she said.

The findings were published in the September issue of the international journal Advanced Science.


nbgkoo@heraldcorp.com