Lithium-Ion Battery Cathode Recycling through a Closed-Loop Process Using a Choline Chloride-Ethylene Glycol-Based...

Area of Science:

• Materials Science
• Electrochemistry
• Green Chemistry

Background:

• Lithium cobalt oxide (LCO) is a key cathode material in Li-ion batteries.
• Efficient recycling of spent Li-ion batteries is crucial for sustainability.
• Deep eutectic solvents (DES) offer a promising alternative for battery material recovery.

Purpose of the Study:

• To evaluate a choline chloride:ethylene glycol-based DES for dissolving LCO.
• To investigate the effect of hydrochloric acid (HCl) on LCO dissolution.
• To assess the recovery and reuse potential of the DES system.

Main Methods:

• Dissolution of commercial LCO powder and spent battery cathodes using a DES.
• Addition of HCl to facilitate LCO dissolution.
• Precipitation of cobalt (Co) and lithium (Li) using lithium carbonate (Li2CO3).
• Multiple cycles of DES reuse.

Main Results:

• Rapid and efficient LCO dissolution achieved within 2 hours at 80°C with optimal HCl addition.
• Complete dissolution observed when adding >3 protons per cobalt atom.
• Co and Li successfully precipitated without DES degradation (pH < 10).
• DES demonstrated efficiency over two reuse cycles with no detected degradation products.

Conclusions:

• The DES system with HCl is a viable and efficient method for LCO dissolution from Li-ion batteries.
• This approach offers advantages over traditional methods in terms of reaction time and temperature.
• The DES can be reused, supporting sustainable battery recycling processes.