Quantitation of the dissolution of battery-grade copper foils in lithium-ion battery electrolytes by flame atomic absorption spectroscopy

Atomic absorption spectroscopy (AAS) was shown to be an effective method to quantitatively evaluate the stability of battery-grade copper foils in lithium-ion battery electrolytes at open-circuit. The results showed that copper stability was different between 'fresh' electrolyte and electrolytes that had been 'aged' for 6 months. In the 'fresh' electrolyte, the copper foils showed a small amount of dissolution (up to ∼50 ppm) during their storage for up to 20 weeks. In the 'aged' electrolyte, a large amount of copper dissolution (up to several hundred ppm) was found. The study showed that the condition of the electrolytes was critical to the stability of the copper foils