Selective lithium recovery from leachates of spent NMC cathodes using deep eutectic solvent-impregnated activated...

Area of Science:

• Materials Science
• Chemical Engineering
• Electrochemistry

Background:

• Spent lithium-ion batteries pose environmental challenges.
• Efficient recovery of critical metals like lithium is crucial for sustainable recycling.
• Conventional methods for lithium extraction often lack selectivity and efficiency.

Purpose of the Study:

• To develop a selective adsorbent for lithium recovery from complex aqueous streams.
• To investigate the performance of deep eutectic solvent-impregnated activated carbon (AC-DES) for lithium extraction.
• To demonstrate the application of AC-DES in recycling spent lithium-ion batteries.

Main Methods:

• Immobilization of a functional deep eutectic solvent (DES) phase onto activated carbon (AC).
• Optimization of adsorption conditions including pH, adsorbent dosage, and time.
• Application of AC-DES for lithium extraction from ethylenediaminetetraacetic acid (EDTA) leachates of spent NMC532 cathodes.
• Characterization using kinetic, isotherm, pH-dependent analyses, material characterization, and density functional theory (DFT) calculations.

Main Results:

• AC-DES achieved up to 99% lithium removal with high selectivity over transition metals.
• The adsorbent demonstrated excellent stability and reusability over four cycles with minimal performance loss.
• Efficient lithium recovery was achieved using a mild acid solution (0.7 M HCl).
• Successful selective lithium extraction from complex leachates of spent battery cathodes was demonstrated.

Conclusions:

• AC-DES provides a tunable coordination environment for preferential Li+ binding.
• The developed adsorbent offers an effective and selective platform for lithium recovery from complex streams.
• This approach presents a promising alternative to conventional solvent-based extraction systems for battery recycling.