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 cells 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 much better quick-charge capability compared to that of graphite cells. In this paper, a series of experiments was carried out in order to characterize the difference in quick-charge capability between graphite and coke anode cells. Lithium manganese oxide was used as the cathode material. A mathematical simulation model developed by Newman and Doyle [J. Newman and M. Doyle, J. Electrochem. Sec. 143 (1996) 1890.] was also used in order to explore the change of lithium distribution in the anode as the cells were charged and discharged. The simulation results supported the experimental observation that coke has a superior ability to quickly distribute the lithium into the anode during high-rate charging. (C) 1998 Elsevier Science S.A. All rights reserved.