Development of High Rate Capable Graphite Anode Materials For Large High Power Lithium Ion Batteries

摘要

Development of large lithium ion batteries for high power applications such as hybrid electrical vehicles demands low cost and high rate capable electrode materials. However, significant obstacles exist in developing graphite anode materials to meet such demands. These obstacles include: a) Rapid decrease of first cycle coulombic efficiency when the particle size of graphite powders is reduced to meet high rate requirements; b) Significant reduction of thermal stability of graphite anode materials due to increased surface area and irreversible capacity loss; and c) High cost of manufacturing fine graphite particles ( < 10 μm) with specialized shapes required to mitigate the drawback of low efficiency. Leveraging extensive corporate knowledge of petroleum carbons and complex coking technology, ConocoPhillips Company (COP) has developed a process to produce very fine graphite powders for competitive cost, high rate capable anode applications. The accompanying poster demonstrates that graphite powders made with the ConocoPhillips proprietary process have high capacity and very low initial irreversible capacity loss. Electrodes made with the ConocoPhillips materials, are specifically designed to be high rate capable. The COP graphite powders generate significantly less heat than comparable graphite powders at elevated temperatures for the same charged state. Therefore, these powders are particularly suited as the anode material for large, high power lithium ion batteries.