Quantitative Mass Transport Limits of Depleted Salt Solutions in Severe Thermal Swings
Dynamic current derating derived from localized salt diffusion kinetics prevents sub-zero lithium plating and costly field warranty failures.
Non-Destructive Stripping
Meaning
Separation techniques in lithium-ion battery recycling detach active electrode coatings from metallic current collector foils without damaging underlying aluminum or copper substrates. The non-destructive stripping process uses mild aqueous solutions or selective green solvents to weaken binder adhesion while leaving foil surfaces intact. Intact current collector foils command higher market value and permit direct recycling of intact cathode powders.
The method operates on uncalendered or lightly bound electrode stock, losing efficiency when cross-linked polymer binders resist chemical dissolution.
Delamination Mechanism
Selective solvent penetration targets polyvinylidene fluoride binders at the foil interface. Liquid swelling reduces interfacial shear strength, allowing active coating layers to peel off cleanly under gentle fluid shearing forces. Water-based processing utilizing temperature-controlled washing tanks avoids hazardous organic emissions while stripping cathode coatings efficiently.
Material Yield
High-purity recovery streams prevent contamination between aluminum substrates and transition metal oxide powders. Intact active particles preserve original crystal structures, allowing direct re-synthesis into new battery electrodes without energy-intensive pyrometallurgical smelting. Recovered copper and aluminum foils return directly to metal refining streams without contamination from black mass residues.
Process Boundary
Strongly bound or aged electrodes require chemical pretreatments that increase process fluid consumption. High solvent residence times slow continuous recycling lines, forcing operators to balance stripping selectivity against mechanical throughput demands. Thermal degradation during prior cell operating life creates stubborn binder residue that requires elevated wash temperatures.