Charge/discharge efficiency improvement by the incorporation of conductive carbons in the carbon anode of Li-ion batteries

Influence of the conductive additive loading on the anode performance of Li-ion battery was investigated for the coated anode where graphitized mesophase carbon fiber (MCF) was used as an active material, and loaded with natural graphite (NG), acetylene black (AB) or Ketjen black (KB). Incorporation of the conductive additive was quite effective to improve not only the cycle life, but also the rate of the electrochemical reaction. In addition, we found that the initial irreversible charging capacity (IICC) of MCF was suppressed to a great extent. The effectiveness was dependent on the kind of material loaded. On the other hand, making a homogeneous slurry for coating was found to be a key factor for the performance improvement. The most preferable choice of the preparation condition gave rise to a dramatic improvement. In contrast to these advantages, the carbon blacks showed a large IICC inherent to the materials which is an issue to be solved for actual use. (C) 2000 Elsevier Science S.A. All rights reserved.