Comparison of Cycling Performance of Lithium Ion Cell Anode Graphites

Abstract

Battery grade graphite products from major suppliers to the battery industry were evaluated in 2325 coin cells with lithium counter electrodes. First and subsequent cycle efficiency, discharge capacity, and discharge rate performance were measured to compare these anode materials. A formula has been developed to utilize lithium ion battery cycling performance data to estimate the overall battery cost, relative to the cost of a battery using MCMB. This analysis indicates that replacing MCMB with CPG-8 (Conoco Phillips) would reduce battery cost (including consideration of a replacement frequency driven by the anode) by 40% (assuming equal graphite prices), whereas use of each of the other graphites would lead to a more costly battery. Therefore we chose CPG-8 as the new baseline graphite for the BATT Program. Significant or strong correlations were found between graphite particle surface area and first cycle irreversible capacity, particle size and rate capacity, and rhombohedral fraction and discharge capacity.