The possibility of using low-purity natural graphite as an anode active material for lithium-ion batteries has been investigated. Pristine and modified natural graphites showed different degrees of crystallinity based on XRD and Raman measurements. Whereas the reversible capacities of pristine and modified natural graphites were similar, the latter had better cycle performance. The dissolution of impurities from the natural graphite into the electrolyte was found to be negligible based on ICP-MS analysis.

Keywords: Lithium-ion batteries, Natural graphite, Soft carbon, Impurity, Dissolution.