The carbon-electrolyte interface at high cathodic voltages

Abstract

Different carbon materials (graphitic and carbon black) were investigated with respect to their electrochemical stability at high voltages in organic electrolytes typically used for Li-ion batteries. The materials were characterized with respect to crystallinity, surface area and surface structure. Electrodes were fabricated from all materials, and characterized by electrochemical techniques, including galvanostatic cycling, cyclic voltammetry, as well as by in-situ XRD. The results from galvanostatic cycling show that the first cycle irreversible loss correlates with the edge surface area, and that the decomposition products are limiting intercalation and de-intercalation after multiple cycles. Structural damage is observed for both graphitic materials by in-situ XRD during the first cycle, no further damage was observed upon repeated cycling. A means of improving reversibility and preventing structural damage of the carbon materials is finally suggested, based on results obtained with an anion receptor additive.