ELECTROCHEMICAL INTERCALATION OF SODIUM-IONS INTO FULLERENE

Electrochemical intercalation of sodium ions into C60 or C60/C70 mixtu res has been obtained in solid state cells working with a ionic conduc ting polymeric electrolyte. Low speed cyclic voltammetry and low inten sity galvanostatic charge experiments give evidence for five successiv e redox states, as previously noticed for lithium ion intercalation. R eduction potentials of fullerene are strongly dependent on the experim ental elaboration conditions of the composite working electrode (fulle rene associated with a binding material) and on the open circuit volta ge of the cell before intercalation. Preliminary X-ray and electron di ffraction studies have allowed the identification of different NaxC60 phases.