FOLIATED NATURAL GRAPHITE AS THE ANODE MATERIAL FOR RECHARGEABLE LITHIUM-ION CELLS

Natural graphite with a high capacity for lithium-ion cells is obtaine d by the chemical flaking of natural graphite along cleavage planes. F laking of graphite (foliated graphite) is obtained via: (i) formation of expanded graphite from natural graphite by acid treatment, and (ii) mechanical and ultrasonic powdering of expanded graphite. This treatm ent is useful even for natural graphite, that contains a large ash con tent, which shows very poor capacity and large polarization. (C) 1997 Elsevier Science S.A.