COKE VS GRAPHITE AS ANODES FOR LITHIUM-ION BATTERIES

The respective rapid charge capabilities for graphite and coke for use in lithium-ion electrochemical cells were investigated. Lithium-ion c ells with graphite anodes showed a poor ability to be rapidly charged due to the nature of the lithium intercalation process associated with graphite. By contrast, lithium-ion cells with coke anodes showed a mu ch better quick-charge capability compared to that of graphite cells. In this paper, a series of experiments was carried out in order to cha racterize the difference in quick-charge capability between graphite a nd coke anode cells. Lithium manganese oxide was used as the cathode m aterial. A mathematical simulation model developed by Newman and Doyle [J. Newman and M. Doyle, J. Electrochem. Sec. 143 (1996) 1890.] was a lso used in order to explore the change of lithium distribution in the anode as the cells were charged and discharged. The simulation result s supported the experimental observation that coke has a superior abil ity to quickly distribute the lithium into the anode during high-rate charging. (C) 1998 Elsevier Science S.A. All rights reserved.