Publications Details
Corrosion of current-collector materials in Li-ion cells
The primary current-collector materials being used in lithium-ion cells are susceptible to environmental degradation: aluminum to pitting corrosion and copper to environmentally assisted cracking. Pitting occurs at the highly oxidizing potentials associated with the positive-electrode charge condition. However, the pitting mechanism is more complex than that typically observed in aqueous systems in that the pits are filled with a mixed metal/oxide product and exist as mounds or nodules on the surface. Electrochemical impedance was shown to be an effective analytical tool for quantification and verification of visual observations and trends. Two fluorocarbon-based coatings were shown to improve the resistance of Al to localized pitting. Finally, environmental cracking of copper can occur at or near the lithium potential and only if specific metallurgical conditions exist (work hardening and large grain size).