Quantitation of the dissolution of the graphite-coated copper foil in lithium-ion battery electrolytes by flame atomic absorption spectroscopy

Atomic absorption spectroscopy (AAS) was used to quantitatively evaluate the stability of copper foils coated with graphite and binder in lithium (Li)-ion battery electrolytes at open-circuit. The results showed that copper dissolution was extremely small in fresh electrolyte. However, atmospheric exposure markedly influenced the stability of copper and caused large amounts of dissolution. In addition, copper dissolution was found to increase (up to several hundred ppm) in electrolyte that had been aged for 6 months. The study showed that the condition of the electrolytes was critical to the stability of the graphite-coated copper foils.