A sustainable approach to cathode delamination using a green solvent

Area of Science:

• Materials Science
• Green Chemistry
• Sustainable Energy

Background:

• Direct cathode recycling is essential for end-of-life (EoL) Li-ion batteries.
• Current methods often use toxic solvents like N-methylpyrrolidone (NMP).
• Developing environmentally friendly delamination processes is critical.

Purpose of the Study:

• To investigate dimethyl isosorbide (DMI) as a green solvent for cathode delamination.
• To understand the mechanism of polyvinylidene fluoride (PVDF) binder removal by DMI.
• To assess the preservation of cathode active materials (AMs) and aluminum foil.

Main Methods:

• Extraction of cathode AMs using DMI as a solvent for PVDF binder.
• Mechanistic studies involving polymer-solvent interactions and hydrogen bonding.
• Analytical characterization using 1H NMR, FTIR, XRD, and SEM-EDS.

Main Results:

• DMI effectively dissolves PVDF binder, enabling delamination of AMs from Al current collectors.
• The mechanism involves DMI penetrating PVDF crystalline regions and forming hydrogen bonds.
• Recovered AMs, PVDF, and Al foil maintain their molecular, micro, and crystal structures.

Conclusions:

• DMI offers a sustainable and effective alternative to toxic NMP for direct cathode recycling.
• This green solvent facilitates environmentally friendly delamination of battery cathodes.
• The preserved integrity of materials supports a circular economy approach for Li-ion batteries.