Characteristics of carbon-coated graphite prepared from mixture of graphite and polyvinylchloride as anode materials for lithium ion batteries

A carbon-coated graphite is investigated as the negative electrode for Li-i on batteries. The carbon-coated graphite particles are prepared by simple h eat-treatment of mixtures, of graphite and poly(vinyl chloride), PVC, at 80 0-1000 degreesC in an argon flow. The carbon coating reduces significantly the initial irreversible capacity of the graphite in a propylene carbonate- based electrolyte, by suppressing the solvated lithium ion intercalation, a nd also improves the initial charge-discharge coulombic efficiency. By carb on coating, the specific surface area of graphite particles is greatly incr eased. These findings can be explained by assuming that a turbostratic stru cture of PVC-carbon resists irreversible side-reactions which are controlle d predominantly by active, edge surface sites. (C) 2001 Elsevier Science B. V. All rights reserved.